// SPDX-License-Identifier: GPL-2.0
#include <fcntl.h>
#include <stdio.h>
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <inttypes.h>

#include "compress.h"
#include "dso.h"
#include "libbfd.h"
#include "map.h"
#include "maps.h"
#include "symbol.h"
#include "symsrc.h"
#include "machine.h"
#include "vdso.h"
#include "debug.h"
#include "util/copyfile.h"
#include <linux/ctype.h>
#include <linux/kernel.h>
#include <linux/zalloc.h>
#include <linux/string.h>
#include <symbol/kallsyms.h>
#include <internal/lib.h>

#ifndef EM_AARCH64
#define EM_AARCH64      183  /* ARM 64 bit */
#endif

#ifndef EM_LOONGARCH
#define EM_LOONGARCH    258
#endif

#ifndef ELF32_ST_VISIBILITY
#define ELF32_ST_VISIBILITY(o)  ((o) & 0x03)
#endif

/* For ELF64 the definitions are the same.  */
#ifndef ELF64_ST_VISIBILITY
#define ELF64_ST_VISIBILITY(o)  ELF32_ST_VISIBILITY (o)
#endif

/* How to extract information held in the st_other field.  */
#ifndef GELF_ST_VISIBILITY
#define GELF_ST_VISIBILITY(val) ELF64_ST_VISIBILITY (val)
#endif

typedef Elf64_Nhdr GElf_Nhdr;


#ifndef HAVE_ELF_GETPHDRNUM_SUPPORT
static int elf_getphdrnum(Elf *elf, size_t *dst)
{
        GElf_Ehdr gehdr;
        GElf_Ehdr *ehdr;

        ehdr = gelf_getehdr(elf, &gehdr);
        if (!ehdr)
                return -1;

        *dst = ehdr->e_phnum;

        return 0;
}
#endif

#ifndef HAVE_ELF_GETSHDRSTRNDX_SUPPORT
static int elf_getshdrstrndx(Elf *elf __maybe_unused, size_t *dst __maybe_unused)
{
        pr_err("%s: update your libelf to > 0.140, this one lacks elf_getshdrstrndx().\n", __func__);
        return -1;
}
#endif

#ifndef NT_GNU_BUILD_ID
#define NT_GNU_BUILD_ID 3
#endif

/**
 * elf_symtab__for_each_symbol - iterate thru all the symbols
 *
 * @syms: struct elf_symtab instance to iterate
 * @idx: uint32_t idx
 * @sym: GElf_Sym iterator
 */
#define elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) \
        for (idx = 0, gelf_getsym(syms, idx, &sym);\
             idx < nr_syms; \
             idx++, gelf_getsym(syms, idx, &sym))

static inline uint8_t elf_sym__type(const GElf_Sym *sym)
{
        return GELF_ST_TYPE(sym->st_info);
}

static inline uint8_t elf_sym__visibility(const GElf_Sym *sym)
{
        return GELF_ST_VISIBILITY(sym->st_other);
}

#ifndef STT_GNU_IFUNC
#define STT_GNU_IFUNC 10
#endif

static inline int elf_sym__is_function(const GElf_Sym *sym)
{
        return (elf_sym__type(sym) == STT_FUNC ||
                elf_sym__type(sym) == STT_GNU_IFUNC) &&
               sym->st_name != 0 &&
               sym->st_shndx != SHN_UNDEF;
}

static inline bool elf_sym__is_object(const GElf_Sym *sym)
{
        return elf_sym__type(sym) == STT_OBJECT &&
                sym->st_name != 0 &&
                sym->st_shndx != SHN_UNDEF;
}

static inline int elf_sym__is_label(const GElf_Sym *sym)
{
        return elf_sym__type(sym) == STT_NOTYPE &&
                sym->st_name != 0 &&
                sym->st_shndx != SHN_UNDEF &&
                sym->st_shndx != SHN_ABS &&
                elf_sym__visibility(sym) != STV_HIDDEN &&
                elf_sym__visibility(sym) != STV_INTERNAL;
}

static bool elf_sym__filter(GElf_Sym *sym)
{
        return elf_sym__is_function(sym) || elf_sym__is_object(sym);
}

static inline const char *elf_sym__name(const GElf_Sym *sym,
                                        const Elf_Data *symstrs)
{
        return symstrs->d_buf + sym->st_name;
}

static inline const char *elf_sec__name(const GElf_Shdr *shdr,
                                        const Elf_Data *secstrs)
{
        return secstrs->d_buf + shdr->sh_name;
}

static inline int elf_sec__is_text(const GElf_Shdr *shdr,
                                        const Elf_Data *secstrs)
{
        return strstr(elf_sec__name(shdr, secstrs), "text") != NULL;
}

static inline bool elf_sec__is_data(const GElf_Shdr *shdr,
                                    const Elf_Data *secstrs)
{
        return strstr(elf_sec__name(shdr, secstrs), "data") != NULL;
}

static bool elf_sec__filter(GElf_Shdr *shdr, Elf_Data *secstrs)
{
        return elf_sec__is_text(shdr, secstrs) ||
               elf_sec__is_data(shdr, secstrs);
}

static size_t elf_addr_to_index(Elf *elf, GElf_Addr addr)
{
        Elf_Scn *sec = NULL;
        GElf_Shdr shdr;
        size_t cnt = 1;

        while ((sec = elf_nextscn(elf, sec)) != NULL) {
                gelf_getshdr(sec, &shdr);

                if ((addr >= shdr.sh_addr) &&
                    (addr < (shdr.sh_addr + shdr.sh_size)))
                        return cnt;

                ++cnt;
        }

        return -1;
}

Elf_Scn *elf_section_by_name(Elf *elf, GElf_Ehdr *ep,
                             GElf_Shdr *shp, const char *name, size_t *idx)
{
        Elf_Scn *sec = NULL;
        size_t cnt = 1;

        /* ELF is corrupted/truncated, avoid calling elf_strptr. */
        if (!elf_rawdata(elf_getscn(elf, ep->e_shstrndx), NULL))
                return NULL;

        while ((sec = elf_nextscn(elf, sec)) != NULL) {
                char *str;

                gelf_getshdr(sec, shp);
                str = elf_strptr(elf, ep->e_shstrndx, shp->sh_name);
                if (str && !strcmp(name, str)) {
                        if (idx)
                                *idx = cnt;
                        return sec;
                }
                ++cnt;
        }

        return NULL;
}

bool filename__has_section(const char *filename, const char *sec)
{
        int fd;
        Elf *elf;
        GElf_Ehdr ehdr;
        GElf_Shdr shdr;
        bool found = false;

        fd = open(filename, O_RDONLY);
        if (fd < 0)
                return false;

        elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
        if (elf == NULL)
                goto out;

        if (gelf_getehdr(elf, &ehdr) == NULL)
                goto elf_out;

        found = !!elf_section_by_name(elf, &ehdr, &shdr, sec, NULL);

elf_out:
        elf_end(elf);
out:
        close(fd);
        return found;
}

static int elf_read_program_header(Elf *elf, u64 vaddr, GElf_Phdr *phdr)
{
        size_t i, phdrnum;
        u64 sz;

        if (elf_getphdrnum(elf, &phdrnum))
                return -1;

        for (i = 0; i < phdrnum; i++) {
                if (gelf_getphdr(elf, i, phdr) == NULL)
                        return -1;

                if (phdr->p_type != PT_LOAD)
                        continue;

                sz = max(phdr->p_memsz, phdr->p_filesz);
                if (!sz)
                        continue;

                if (vaddr >= phdr->p_vaddr && (vaddr < phdr->p_vaddr + sz))
                        return 0;
        }

        /* Not found any valid program header */
        return -1;
}

struct rel_info {
        u32             nr_entries;
        u32             *sorted;
        bool            is_rela;
        Elf_Data        *reldata;
        GElf_Rela       rela;
        GElf_Rel        rel;
};

static u32 get_rel_symidx(struct rel_info *ri, u32 idx)
{
        idx = ri->sorted ? ri->sorted[idx] : idx;
        if (ri->is_rela) {
                gelf_getrela(ri->reldata, idx, &ri->rela);
                return GELF_R_SYM(ri->rela.r_info);
        }
        gelf_getrel(ri->reldata, idx, &ri->rel);
        return GELF_R_SYM(ri->rel.r_info);
}

static u64 get_rel_offset(struct rel_info *ri, u32 x)
{
        if (ri->is_rela) {
                GElf_Rela rela;

                gelf_getrela(ri->reldata, x, &rela);
                return rela.r_offset;
        } else {
                GElf_Rel rel;

                gelf_getrel(ri->reldata, x, &rel);
                return rel.r_offset;
        }
}

static int rel_cmp(const void *a, const void *b, void *r)
{
        struct rel_info *ri = r;
        u64 a_offset = get_rel_offset(ri, *(const u32 *)a);
        u64 b_offset = get_rel_offset(ri, *(const u32 *)b);

        return a_offset < b_offset ? -1 : (a_offset > b_offset ? 1 : 0);
}

static int sort_rel(struct rel_info *ri)
{
        size_t sz = sizeof(ri->sorted[0]);
        u32 i;

        ri->sorted = calloc(ri->nr_entries, sz);
        if (!ri->sorted)
                return -1;
        for (i = 0; i < ri->nr_entries; i++)
                ri->sorted[i] = i;
        qsort_r(ri->sorted, ri->nr_entries, sz, rel_cmp, ri);
        return 0;
}

/*
 * For x86_64, the GNU linker is putting IFUNC information in the relocation
 * addend.
 */
static bool addend_may_be_ifunc(GElf_Ehdr *ehdr, struct rel_info *ri)
{
        return ehdr->e_machine == EM_X86_64 && ri->is_rela &&
               GELF_R_TYPE(ri->rela.r_info) == R_X86_64_IRELATIVE;
}

static bool get_ifunc_name(Elf *elf, struct dso *dso, GElf_Ehdr *ehdr,
                           struct rel_info *ri, char *buf, size_t buf_sz)
{
        u64 addr = ri->rela.r_addend;
        struct symbol *sym;
        GElf_Phdr phdr;

        if (!addend_may_be_ifunc(ehdr, ri))
                return false;

        if (elf_read_program_header(elf, addr, &phdr))
                return false;

        addr -= phdr.p_vaddr - phdr.p_offset;

        sym = dso__find_symbol_nocache(dso, addr);

        /* Expecting the address to be an IFUNC or IFUNC alias */
        if (!sym || sym->start != addr || (sym->type != STT_GNU_IFUNC && !sym->ifunc_alias))
                return false;

        snprintf(buf, buf_sz, "%s@plt", sym->name);

        return true;
}

static void exit_rel(struct rel_info *ri)
{
        zfree(&ri->sorted);
}

static bool get_plt_sizes(struct dso *dso, GElf_Ehdr *ehdr, GElf_Shdr *shdr_plt,
                          u64 *plt_header_size, u64 *plt_entry_size)
{
        switch (ehdr->e_machine) {
        case EM_ARM:
                *plt_header_size = 20;
                *plt_entry_size = 12;
                return true;
        case EM_AARCH64:
                *plt_header_size = 32;
                *plt_entry_size = 16;
                return true;
        case EM_LOONGARCH:
                *plt_header_size = 32;
                *plt_entry_size = 16;
                return true;
        case EM_SPARC:
                *plt_header_size = 48;
                *plt_entry_size = 12;
                return true;
        case EM_SPARCV9:
                *plt_header_size = 128;
                *plt_entry_size = 32;
                return true;
        case EM_386:
        case EM_X86_64:
                *plt_entry_size = shdr_plt->sh_entsize;
                /* Size is 8 or 16, if not, assume alignment indicates size */
                if (*plt_entry_size != 8 && *plt_entry_size != 16)
                        *plt_entry_size = shdr_plt->sh_addralign == 8 ? 8 : 16;
                *plt_header_size = *plt_entry_size;
                break;
        default: /* FIXME: s390/alpha/mips/parisc/poperpc/sh/xtensa need to be checked */
                *plt_header_size = shdr_plt->sh_entsize;
                *plt_entry_size = shdr_plt->sh_entsize;
                break;
        }
        if (*plt_entry_size)
                return true;
        pr_debug("Missing PLT entry size for %s\n", dso__long_name(dso));
        return false;
}

static bool machine_is_x86(GElf_Half e_machine)
{
        return e_machine == EM_386 || e_machine == EM_X86_64;
}

struct rela_dyn {
        GElf_Addr       offset;
        u32             sym_idx;
};

struct rela_dyn_info {
        struct dso      *dso;
        Elf_Data        *plt_got_data;
        u32             nr_entries;
        struct rela_dyn *sorted;
        Elf_Data        *dynsym_data;
        Elf_Data        *dynstr_data;
        Elf_Data        *rela_dyn_data;
};

static void exit_rela_dyn(struct rela_dyn_info *di)
{
        zfree(&di->sorted);
}

static int cmp_offset(const void *a, const void *b)
{
        const struct rela_dyn *va = a;
        const struct rela_dyn *vb = b;

        return va->offset < vb->offset ? -1 : (va->offset > vb->offset ? 1 : 0);
}

static int sort_rela_dyn(struct rela_dyn_info *di)
{
        u32 i, n;

        di->sorted = calloc(di->nr_entries, sizeof(di->sorted[0]));
        if (!di->sorted)
                return -1;

        /* Get data for sorting: the offset and symbol index */
        for (i = 0, n = 0; i < di->nr_entries; i++) {
                GElf_Rela rela;
                u32 sym_idx;

                gelf_getrela(di->rela_dyn_data, i, &rela);
                sym_idx = GELF_R_SYM(rela.r_info);
                if (sym_idx) {
                        di->sorted[n].sym_idx = sym_idx;
                        di->sorted[n].offset = rela.r_offset;
                        n += 1;
                }
        }

        /* Sort by offset */
        di->nr_entries = n;
        qsort(di->sorted, n, sizeof(di->sorted[0]), cmp_offset);

        return 0;
}

static void get_rela_dyn_info(Elf *elf, GElf_Ehdr *ehdr, struct rela_dyn_info *di, Elf_Scn *scn)
{
        GElf_Shdr rela_dyn_shdr;
        GElf_Shdr shdr;

        di->plt_got_data = elf_getdata(scn, NULL);

        scn = elf_section_by_name(elf, ehdr, &rela_dyn_shdr, ".rela.dyn", NULL);
        if (!scn || !rela_dyn_shdr.sh_link || !rela_dyn_shdr.sh_entsize)
                return;

        di->nr_entries = rela_dyn_shdr.sh_size / rela_dyn_shdr.sh_entsize;
        di->rela_dyn_data = elf_getdata(scn, NULL);

        scn = elf_getscn(elf, rela_dyn_shdr.sh_link);
        if (!scn || !gelf_getshdr(scn, &shdr) || !shdr.sh_link)
                return;

        di->dynsym_data = elf_getdata(scn, NULL);
        di->dynstr_data = elf_getdata(elf_getscn(elf, shdr.sh_link), NULL);

        if (!di->plt_got_data || !di->dynstr_data || !di->dynsym_data || !di->rela_dyn_data)
                return;

        /* Sort into offset order */
        sort_rela_dyn(di);
}

/* Get instruction displacement from a plt entry for x86_64 */
static u32 get_x86_64_plt_disp(const u8 *p)
{
        u8 endbr64[] = {0xf3, 0x0f, 0x1e, 0xfa};
        int n = 0;

        /* Skip endbr64 */
        if (!memcmp(p, endbr64, sizeof(endbr64)))
                n += sizeof(endbr64);
        /* Skip bnd prefix */
        if (p[n] == 0xf2)
                n += 1;
        /* jmp with 4-byte displacement */
        if (p[n] == 0xff && p[n + 1] == 0x25) {
                u32 disp;

                n += 2;
                /* Also add offset from start of entry to end of instruction */
                memcpy(&disp, p + n, sizeof(disp));
                return n + 4 + le32toh(disp);
        }
        return 0;
}

static bool get_plt_got_name(GElf_Shdr *shdr, size_t i,
                             struct rela_dyn_info *di,
                             char *buf, size_t buf_sz)
{
        struct rela_dyn vi, *vr;
        const char *sym_name;
        char *demangled;
        GElf_Sym sym;
        bool result;
        u32 disp;

        if (!di->sorted)
                return false;

        disp = get_x86_64_plt_disp(di->plt_got_data->d_buf + i);
        if (!disp)
                return false;

        /* Compute target offset of the .plt.got entry */
        vi.offset = shdr->sh_offset + di->plt_got_data->d_off + i + disp;

        /* Find that offset in .rela.dyn (sorted by offset) */
        vr = bsearch(&vi, di->sorted, di->nr_entries, sizeof(di->sorted[0]), cmp_offset);
        if (!vr)
                return false;

        /* Get the associated symbol */
        gelf_getsym(di->dynsym_data, vr->sym_idx, &sym);
        sym_name = elf_sym__name(&sym, di->dynstr_data);
        demangled = dso__demangle_sym(di->dso, /*kmodule=*/0, sym_name);
        if (demangled != NULL)
                sym_name = demangled;

        snprintf(buf, buf_sz, "%s@plt", sym_name);

        result = *sym_name;

        free(demangled);

        return result;
}

static int dso__synthesize_plt_got_symbols(struct dso *dso, Elf *elf,
                                           GElf_Ehdr *ehdr,
                                           char *buf, size_t buf_sz)
{
        struct rela_dyn_info di = { .dso = dso };
        struct symbol *sym;
        GElf_Shdr shdr;
        Elf_Scn *scn;
        int err = -1;
        size_t i;

        scn = elf_section_by_name(elf, ehdr, &shdr, ".plt.got", NULL);
        if (!scn || !shdr.sh_entsize)
                return 0;

        if (ehdr->e_machine == EM_X86_64)
                get_rela_dyn_info(elf, ehdr, &di, scn);

        for (i = 0; i < shdr.sh_size; i += shdr.sh_entsize) {
                if (!get_plt_got_name(&shdr, i, &di, buf, buf_sz))
                        snprintf(buf, buf_sz, "offset_%#" PRIx64 "@plt", (u64)shdr.sh_offset + i);
                sym = symbol__new(shdr.sh_offset + i, shdr.sh_entsize, STB_GLOBAL, STT_FUNC, buf);
                if (!sym)
                        goto out;
                symbols__insert(dso__symbols(dso), sym);
        }
        err = 0;
out:
        exit_rela_dyn(&di);
        return err;
}

/*
 * We need to check if we have a .dynsym, so that we can handle the
 * .plt, synthesizing its symbols, that aren't on the symtabs (be it
 * .dynsym or .symtab).
 * And always look at the original dso, not at debuginfo packages, that
 * have the PLT data stripped out (shdr_rel_plt.sh_type == SHT_NOBITS).
 */
int dso__synthesize_plt_symbols(struct dso *dso, struct symsrc *ss)
{
        uint32_t idx;
        GElf_Sym sym;
        u64 plt_offset, plt_header_size, plt_entry_size;
        GElf_Shdr shdr_plt, plt_sec_shdr;
        struct symbol *f, *plt_sym;
        GElf_Shdr shdr_rel_plt, shdr_dynsym;
        Elf_Data *syms, *symstrs;
        Elf_Scn *scn_plt_rel, *scn_symstrs, *scn_dynsym;
        GElf_Ehdr ehdr;
        char sympltname[1024];
        Elf *elf;
        int nr = 0, err = -1;
        struct rel_info ri = { .is_rela = false };
        bool lazy_plt;

        elf = ss->elf;
        ehdr = ss->ehdr;

        if (!elf_section_by_name(elf, &ehdr, &shdr_plt, ".plt", NULL))
                return 0;

        /*
         * A symbol from a previous section (e.g. .init) can have been expanded
         * by symbols__fixup_end() to overlap .plt. Truncate it before adding
         * a symbol for .plt header.
         */
        f = dso__find_symbol_nocache(dso, shdr_plt.sh_offset);
        if (f && f->start < shdr_plt.sh_offset && f->end > shdr_plt.sh_offset)
                f->end = shdr_plt.sh_offset;

        if (!get_plt_sizes(dso, &ehdr, &shdr_plt, &plt_header_size, &plt_entry_size))
                return 0;

        /* Add a symbol for .plt header */
        plt_sym = symbol__new(shdr_plt.sh_offset, plt_header_size, STB_GLOBAL, STT_FUNC, ".plt");
        if (!plt_sym)
                goto out_elf_end;
        symbols__insert(dso__symbols(dso), plt_sym);

        /* Only x86 has .plt.got */
        if (machine_is_x86(ehdr.e_machine) &&
            dso__synthesize_plt_got_symbols(dso, elf, &ehdr, sympltname, sizeof(sympltname)))
                goto out_elf_end;

        /* Only x86 has .plt.sec */
        if (machine_is_x86(ehdr.e_machine) &&
            elf_section_by_name(elf, &ehdr, &plt_sec_shdr, ".plt.sec", NULL)) {
                if (!get_plt_sizes(dso, &ehdr, &plt_sec_shdr, &plt_header_size, &plt_entry_size))
                        return 0;
                /* Extend .plt symbol to entire .plt */
                plt_sym->end = plt_sym->start + shdr_plt.sh_size;
                /* Use .plt.sec offset */
                plt_offset = plt_sec_shdr.sh_offset;
                lazy_plt = false;
        } else {
                plt_offset = shdr_plt.sh_offset;
                lazy_plt = true;
        }

        scn_plt_rel = elf_section_by_name(elf, &ehdr, &shdr_rel_plt,
                                          ".rela.plt", NULL);
        if (scn_plt_rel == NULL) {
                scn_plt_rel = elf_section_by_name(elf, &ehdr, &shdr_rel_plt,
                                                  ".rel.plt", NULL);
                if (scn_plt_rel == NULL)
                        return 0;
        }

        if (shdr_rel_plt.sh_type != SHT_RELA &&
            shdr_rel_plt.sh_type != SHT_REL)
                return 0;

        if (!shdr_rel_plt.sh_link)
                return 0;

        if (shdr_rel_plt.sh_link == ss->dynsym_idx) {
                scn_dynsym = ss->dynsym;
                shdr_dynsym = ss->dynshdr;
        } else if (shdr_rel_plt.sh_link == ss->symtab_idx) {
                /*
                 * A static executable can have a .plt due to IFUNCs, in which
                 * case .symtab is used not .dynsym.
                 */
                scn_dynsym = ss->symtab;
                shdr_dynsym = ss->symshdr;
        } else {
                goto out_elf_end;
        }

        if (!scn_dynsym)
                return 0;

        /*
         * Fetch the relocation section to find the idxes to the GOT
         * and the symbols in the .dynsym they refer to.
         */
        ri.reldata = elf_getdata(scn_plt_rel, NULL);
        if (!ri.reldata)
                goto out_elf_end;

        syms = elf_getdata(scn_dynsym, NULL);
        if (syms == NULL)
                goto out_elf_end;

        scn_symstrs = elf_getscn(elf, shdr_dynsym.sh_link);
        if (scn_symstrs == NULL)
                goto out_elf_end;

        symstrs = elf_getdata(scn_symstrs, NULL);
        if (symstrs == NULL)
                goto out_elf_end;

        if (symstrs->d_size == 0)
                goto out_elf_end;

        ri.nr_entries = shdr_rel_plt.sh_size / shdr_rel_plt.sh_entsize;

        ri.is_rela = shdr_rel_plt.sh_type == SHT_RELA;

        if (lazy_plt) {
                /*
                 * Assume a .plt with the same number of entries as the number
                 * of relocation entries is not lazy and does not have a header.
                 */
                if (ri.nr_entries * plt_entry_size == shdr_plt.sh_size)
                        dso__delete_symbol(dso, plt_sym);
                else
                        plt_offset += plt_header_size;
        }

        /*
         * x86 doesn't insert IFUNC relocations in .plt order, so sort to get
         * back in order.
         */
        if (machine_is_x86(ehdr.e_machine) && sort_rel(&ri))
                goto out_elf_end;

        for (idx = 0; idx < ri.nr_entries; idx++) {
                const char *elf_name = NULL;
                char *demangled = NULL;

                gelf_getsym(syms, get_rel_symidx(&ri, idx), &sym);

                elf_name = elf_sym__name(&sym, symstrs);
                demangled = dso__demangle_sym(dso, /*kmodule=*/0, elf_name);
                if (demangled)
                        elf_name = demangled;
                if (*elf_name)
                        snprintf(sympltname, sizeof(sympltname), "%s@plt", elf_name);
                else if (!get_ifunc_name(elf, dso, &ehdr, &ri, sympltname, sizeof(sympltname)))
                        snprintf(sympltname, sizeof(sympltname),
                                 "offset_%#" PRIx64 "@plt", plt_offset);
                free(demangled);

                f = symbol__new(plt_offset, plt_entry_size, STB_GLOBAL, STT_FUNC, sympltname);
                if (!f)
                        goto out_elf_end;

                plt_offset += plt_entry_size;
                symbols__insert(dso__symbols(dso), f);
                ++nr;
        }

        err = 0;
out_elf_end:
        exit_rel(&ri);
        if (err == 0)
                return nr;
        pr_debug("%s: problems reading %s PLT info.\n",
                 __func__, dso__long_name(dso));
        return 0;
}

/*
 * Align offset to 4 bytes as needed for note name and descriptor data.
 */
#define NOTE_ALIGN(n) (((n) + 3) & -4U)

static int elf_read_build_id(Elf *elf, void *bf, size_t size)
{
        int err = -1;
        GElf_Ehdr ehdr;
        GElf_Shdr shdr;
        Elf_Data *data;
        Elf_Scn *sec;
        Elf_Kind ek;
        void *ptr;

        if (size < BUILD_ID_SIZE)
                goto out;

        ek = elf_kind(elf);
        if (ek != ELF_K_ELF)
                goto out;

        if (gelf_getehdr(elf, &ehdr) == NULL) {
                pr_err("%s: cannot get elf header.\n", __func__);
                goto out;
        }

        /*
         * Check following sections for notes:
         *   '.note.gnu.build-id'
         *   '.notes'
         *   '.note' (VDSO specific)
         */
        do {
                sec = elf_section_by_name(elf, &ehdr, &shdr,
                                          ".note.gnu.build-id", NULL);
                if (sec)
                        break;

                sec = elf_section_by_name(elf, &ehdr, &shdr,
                                          ".notes", NULL);
                if (sec)
                        break;

                sec = elf_section_by_name(elf, &ehdr, &shdr,
                                          ".note", NULL);
                if (sec)
                        break;

                return err;

        } while (0);

        data = elf_getdata(sec, NULL);
        if (data == NULL)
                goto out;

        ptr = data->d_buf;
        while (ptr < (data->d_buf + data->d_size)) {
                GElf_Nhdr *nhdr = ptr;
                size_t namesz = NOTE_ALIGN(nhdr->n_namesz),
                       descsz = NOTE_ALIGN(nhdr->n_descsz);
                const char *name;

                ptr += sizeof(*nhdr);
                name = ptr;
                ptr += namesz;
                if (nhdr->n_type == NT_GNU_BUILD_ID &&
                    nhdr->n_namesz == sizeof("GNU")) {
                        if (memcmp(name, "GNU", sizeof("GNU")) == 0) {
                                size_t sz = min(size, descsz);
                                memcpy(bf, ptr, sz);
                                memset(bf + sz, 0, size - sz);
                                err = sz;
                                break;
                        }
                }
                ptr += descsz;
        }

out:
        return err;
}

static int read_build_id(const char *filename, struct build_id *bid)
{
        size_t size = sizeof(bid->data);
        int fd, err;
        Elf *elf;

        err = libbfd__read_build_id(filename, bid);
        if (err >= 0)
                goto out;

        if (size < BUILD_ID_SIZE)
                goto out;

        fd = open(filename, O_RDONLY);
        if (fd < 0)
                goto out;

        elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
        if (elf == NULL) {
                pr_debug2("%s: cannot read %s ELF file.\n", __func__, filename);
                goto out_close;
        }

        err = elf_read_build_id(elf, bid->data, size);
        if (err > 0)
                bid->size = err;

        elf_end(elf);
out_close:
        close(fd);
out:
        return err;
}

int filename__read_build_id(const char *filename, struct build_id *bid)
{
        struct kmod_path m = { .name = NULL, };
        char path[PATH_MAX];
        int err;

        if (!filename)
                return -EFAULT;

        errno = 0;
        if (!is_regular_file(filename))
                return errno == 0 ? -EWOULDBLOCK : -errno;

        err = kmod_path__parse(&m, filename);
        if (err)
                return -1;

        if (m.comp) {
                int error = 0, fd;

                fd = filename__decompress(filename, path, sizeof(path), m.comp, &error);
                if (fd < 0) {
                        pr_debug("Failed to decompress (error %d) %s\n",
                                 error, filename);
                        return -1;
                }
                close(fd);
                filename = path;
        }

        err = read_build_id(filename, bid);

        if (m.comp)
                unlink(filename);
        return err;
}

int sysfs__read_build_id(const char *filename, struct build_id *bid)
{
        size_t size = sizeof(bid->data);
        int fd, err = -1;

        fd = open(filename, O_RDONLY);
        if (fd < 0)
                goto out;

        while (1) {
                char bf[BUFSIZ];
                GElf_Nhdr nhdr;
                size_t namesz, descsz;

                if (read(fd, &nhdr, sizeof(nhdr)) != sizeof(nhdr))
                        break;

                namesz = NOTE_ALIGN(nhdr.n_namesz);
                descsz = NOTE_ALIGN(nhdr.n_descsz);
                if (nhdr.n_type == NT_GNU_BUILD_ID &&
                    nhdr.n_namesz == sizeof("GNU")) {
                        if (read(fd, bf, namesz) != (ssize_t)namesz)
                                break;
                        if (memcmp(bf, "GNU", sizeof("GNU")) == 0) {
                                size_t sz = min(descsz, size);
                                if (read(fd, bid->data, sz) == (ssize_t)sz) {
                                        memset(bid->data + sz, 0, size - sz);
                                        bid->size = sz;
                                        err = 0;
                                        break;
                                }
                        } else if (read(fd, bf, descsz) != (ssize_t)descsz)
                                break;
                } else {
                        int n = namesz + descsz;

                        if (n > (int)sizeof(bf)) {
                                n = sizeof(bf);
                                pr_debug("%s: truncating reading of build id in sysfs file %s: n_namesz=%u, n_descsz=%u.\n",
                                         __func__, filename, nhdr.n_namesz, nhdr.n_descsz);
                        }
                        if (read(fd, bf, n) != n)
                                break;
                }
        }
        close(fd);
out:
        return err;
}

int filename__read_debuglink(const char *filename, char *debuglink,
                             size_t size)
{
        int fd, err = -1;
        Elf *elf;
        GElf_Ehdr ehdr;
        GElf_Shdr shdr;
        Elf_Data *data;
        Elf_Scn *sec;
        Elf_Kind ek;

        err = libbfd_filename__read_debuglink(filename, debuglink, size);
        if (err >= 0)
                goto out;

        fd = open(filename, O_RDONLY);
        if (fd < 0)
                goto out;

        elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
        if (elf == NULL) {
                pr_debug2("%s: cannot read %s ELF file.\n", __func__, filename);
                goto out_close;
        }

        ek = elf_kind(elf);
        if (ek != ELF_K_ELF)
                goto out_elf_end;

        if (gelf_getehdr(elf, &ehdr) == NULL) {
                pr_err("%s: cannot get elf header.\n", __func__);
                goto out_elf_end;
        }

        sec = elf_section_by_name(elf, &ehdr, &shdr,
                                  ".gnu_debuglink", NULL);
        if (sec == NULL)
                goto out_elf_end;

        data = elf_getdata(sec, NULL);
        if (data == NULL)
                goto out_elf_end;

        /* the start of this section is a zero-terminated string */
        strncpy(debuglink, data->d_buf, size);

        err = 0;

out_elf_end:
        elf_end(elf);
out_close:
        close(fd);
out:
        return err;
}

bool symsrc__possibly_runtime(struct symsrc *ss)
{
        return ss->dynsym || ss->opdsec;
}

bool symsrc__has_symtab(struct symsrc *ss)
{
        return ss->symtab != NULL;
}

void symsrc__destroy(struct symsrc *ss)
{
        zfree(&ss->name);
        elf_end(ss->elf);
        close(ss->fd);
}

bool elf__needs_adjust_symbols(GElf_Ehdr ehdr)
{
        /*
         * Usually vmlinux is an ELF file with type ET_EXEC for most
         * architectures; except Arm64 kernel is linked with option
         * '-share', so need to check type ET_DYN.
         */
        return ehdr.e_type == ET_EXEC || ehdr.e_type == ET_REL ||
               ehdr.e_type == ET_DYN;
}

static Elf *read_gnu_debugdata(struct dso *dso, Elf *elf, const char *name, int *fd_ret)
{
        Elf *elf_embedded;
        GElf_Ehdr ehdr;
        GElf_Shdr shdr;
        Elf_Scn *scn;
        Elf_Data *scn_data;
        FILE *wrapped;
        size_t shndx;
        char temp_filename[] = "/tmp/perf.gnu_debugdata.elf.XXXXXX";
        int ret, temp_fd;

        if (gelf_getehdr(elf, &ehdr) == NULL) {
                pr_debug("%s: cannot read %s ELF file.\n", __func__, name);
                *dso__load_errno(dso) = DSO_LOAD_ERRNO__INVALID_ELF;
                return NULL;
        }

        scn = elf_section_by_name(elf, &ehdr, &shdr, ".gnu_debugdata", &shndx);
        if (!scn) {
                *dso__load_errno(dso) = -ENOENT;
                return NULL;
        }

        if (shdr.sh_type == SHT_NOBITS) {
                pr_debug("%s: .gnu_debugdata of ELF file %s has no data.\n", __func__, name);
                *dso__load_errno(dso) = DSO_LOAD_ERRNO__INVALID_ELF;
                return NULL;
        }

        scn_data = elf_rawdata(scn, NULL);
        if (!scn_data) {
                pr_debug("%s: error reading .gnu_debugdata of %s: %s\n", __func__,
                         name, elf_errmsg(-1));
                *dso__load_errno(dso) = DSO_LOAD_ERRNO__INVALID_ELF;
                return NULL;
        }

        wrapped = fmemopen(scn_data->d_buf, scn_data->d_size, "r");
        if (!wrapped) {
                pr_debug("%s: fmemopen: %m\n", __func__);
                *dso__load_errno(dso) = -errno;
                return NULL;
        }

        temp_fd = mkstemp(temp_filename);
        if (temp_fd < 0) {
                pr_debug("%s: mkstemp: %m\n", __func__);
                *dso__load_errno(dso) = -errno;
                fclose(wrapped);
                return NULL;
        }
        unlink(temp_filename);

        ret = lzma_decompress_stream_to_file(wrapped, temp_fd);
        fclose(wrapped);
        if (ret < 0) {
                *dso__load_errno(dso) = -errno;
                close(temp_fd);
                return NULL;
        }

        elf_embedded = elf_begin(temp_fd, PERF_ELF_C_READ_MMAP, NULL);
        if (!elf_embedded) {
                pr_debug("%s: error reading .gnu_debugdata of %s: %s\n", __func__,
                         name, elf_errmsg(-1));
                *dso__load_errno(dso) = DSO_LOAD_ERRNO__INVALID_ELF;
                close(temp_fd);
                return NULL;
        }
        pr_debug("%s: using .gnu_debugdata of %s\n", __func__, name);
        *fd_ret = temp_fd;
        return elf_embedded;
}

int symsrc__init(struct symsrc *ss, struct dso *dso, const char *name,
                 enum dso_binary_type type)
{
        GElf_Ehdr ehdr;
        Elf *elf;
        int fd;

        if (dso__needs_decompress(dso)) {
                fd = dso__decompress_kmodule_fd(dso, name);
                if (fd < 0)
                        return -1;

                type = dso__symtab_type(dso);
        } else {
                fd = open(name, O_RDONLY);
                if (fd < 0) {
                        *dso__load_errno(dso) = errno;
                        return -1;
                }
        }

        elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
        if (elf == NULL) {
                pr_debug("%s: cannot read %s ELF file.\n", __func__, name);
                *dso__load_errno(dso) = DSO_LOAD_ERRNO__INVALID_ELF;
                goto out_close;
        }

        if (type == DSO_BINARY_TYPE__GNU_DEBUGDATA) {
                int new_fd;
                Elf *embedded = read_gnu_debugdata(dso, elf, name, &new_fd);

                if (!embedded)
                        goto out_elf_end;

                elf_end(elf);
                close(fd);
                fd = new_fd;
                elf = embedded;
        }

        if (gelf_getehdr(elf, &ehdr) == NULL) {
                *dso__load_errno(dso) = DSO_LOAD_ERRNO__INVALID_ELF;
                pr_debug("%s: cannot get elf header.\n", __func__);
                goto out_elf_end;
        }

        if (dso__swap_init(dso, ehdr.e_ident[EI_DATA])) {
                *dso__load_errno(dso) = DSO_LOAD_ERRNO__INTERNAL_ERROR;
                goto out_elf_end;
        }

        /* Always reject images with a mismatched build-id: */
        if (dso__has_build_id(dso) && !symbol_conf.ignore_vmlinux_buildid) {
                u8 build_id[BUILD_ID_SIZE];
                struct build_id bid;
                int size;

                size = elf_read_build_id(elf, build_id, BUILD_ID_SIZE);
                if (size <= 0) {
                        *dso__load_errno(dso) = DSO_LOAD_ERRNO__CANNOT_READ_BUILDID;
                        goto out_elf_end;
                }

                build_id__init(&bid, build_id, size);
                if (!dso__build_id_equal(dso, &bid)) {
                        pr_debug("%s: build id mismatch for %s.\n", __func__, name);
                        *dso__load_errno(dso) = DSO_LOAD_ERRNO__MISMATCHING_BUILDID;
                        goto out_elf_end;
                }
        }

        ss->is_64_bit = (gelf_getclass(elf) == ELFCLASS64);

        ss->symtab_idx = 0;
        ss->symtab = elf_section_by_name(elf, &ehdr, &ss->symshdr, ".symtab",
                        &ss->symtab_idx);
        if (ss->symshdr.sh_type != SHT_SYMTAB)
                ss->symtab = NULL;

        ss->dynsym_idx = 0;
        ss->dynsym = elf_section_by_name(elf, &ehdr, &ss->dynshdr, ".dynsym",
                        &ss->dynsym_idx);
        if (ss->dynshdr.sh_type != SHT_DYNSYM)
                ss->dynsym = NULL;

        ss->opdidx = 0;
        ss->opdsec = elf_section_by_name(elf, &ehdr, &ss->opdshdr, ".opd",
                        &ss->opdidx);
        if (ss->opdshdr.sh_type != SHT_PROGBITS)
                ss->opdsec = NULL;

        if (dso__kernel(dso) == DSO_SPACE__USER)
                ss->adjust_symbols = true;
        else
                ss->adjust_symbols = elf__needs_adjust_symbols(ehdr);

        ss->name   = strdup(name);
        if (!ss->name) {
                *dso__load_errno(dso) = errno;
                goto out_elf_end;
        }

        ss->elf    = elf;
        ss->fd     = fd;
        ss->ehdr   = ehdr;
        ss->type   = type;

        return 0;

out_elf_end:
        elf_end(elf);
out_close:
        close(fd);
        return -1;
}

static bool is_exe_text(int flags)
{
        return (flags & (SHF_ALLOC | SHF_EXECINSTR)) == (SHF_ALLOC | SHF_EXECINSTR);
}

/*
 * Some executable module sections like .noinstr.text might be laid out with
 * .text so they can use the same mapping (memory address to file offset).
 * Check if that is the case. Refer to kernel layout_sections(). Return the
 * maximum offset.
 */
static u64 max_text_section(Elf *elf, GElf_Ehdr *ehdr)
{
        Elf_Scn *sec = NULL;
        GElf_Shdr shdr;
        u64 offs = 0;

        /* Doesn't work for some arch */
        if (ehdr->e_machine == EM_PARISC ||
            ehdr->e_machine == EM_ALPHA)
                return 0;

        /* ELF is corrupted/truncated, avoid calling elf_strptr. */
        if (!elf_rawdata(elf_getscn(elf, ehdr->e_shstrndx), NULL))
                return 0;

        while ((sec = elf_nextscn(elf, sec)) != NULL) {
                char *sec_name;

                if (!gelf_getshdr(sec, &shdr))
                        break;

                if (!is_exe_text(shdr.sh_flags))
                        continue;

                /* .init and .exit sections are not placed with .text */
                sec_name = elf_strptr(elf, ehdr->e_shstrndx, shdr.sh_name);
                if (!sec_name ||
                    strstarts(sec_name, ".init") ||
                    strstarts(sec_name, ".exit"))
                        break;

                /* Must be next to previous, assumes .text is first */
                if (offs && PERF_ALIGN(offs, shdr.sh_addralign ?: 1) != shdr.sh_offset)
                        break;

                offs = shdr.sh_offset + shdr.sh_size;
        }

        return offs;
}

/**
 * ref_reloc_sym_not_found - has kernel relocation symbol been found.
 * @kmap: kernel maps and relocation reference symbol
 *
 * This function returns %true if we are dealing with the kernel maps and the
 * relocation reference symbol has not yet been found.  Otherwise %false is
 * returned.
 */
static bool ref_reloc_sym_not_found(struct kmap *kmap)
{
        return kmap && kmap->ref_reloc_sym && kmap->ref_reloc_sym->name &&
               !kmap->ref_reloc_sym->unrelocated_addr;
}

/**
 * ref_reloc - kernel relocation offset.
 * @kmap: kernel maps and relocation reference symbol
 *
 * This function returns the offset of kernel addresses as determined by using
 * the relocation reference symbol i.e. if the kernel has not been relocated
 * then the return value is zero.
 */
static u64 ref_reloc(struct kmap *kmap)
{
        if (kmap && kmap->ref_reloc_sym &&
            kmap->ref_reloc_sym->unrelocated_addr)
                return kmap->ref_reloc_sym->addr -
                       kmap->ref_reloc_sym->unrelocated_addr;
        return 0;
}

void __weak arch__sym_update(struct symbol *s __maybe_unused,
                GElf_Sym *sym __maybe_unused) { }

static int dso__process_kernel_symbol(struct dso *dso, struct map *map,
                                      GElf_Sym *sym, GElf_Shdr *shdr,
                                      struct maps *kmaps, struct kmap *kmap,
                                      struct dso **curr_dsop,
                                      const char *section_name,
                                      bool adjust_kernel_syms, bool kmodule, bool *remap_kernel,
                                      u64 max_text_sh_offset)
{
        struct dso *curr_dso = *curr_dsop;
        struct map *curr_map;
        char dso_name[PATH_MAX];

        /* Adjust symbol to map to file offset */
        if (adjust_kernel_syms)
                sym->st_value -= shdr->sh_addr - shdr->sh_offset;

        if (strcmp(section_name, (dso__short_name(curr_dso) + dso__short_name_len(dso))) == 0)
                return 0;

        if (strcmp(section_name, ".text") == 0) {
                /*
                 * The initial kernel mapping is based on
                 * kallsyms and identity maps.  Overwrite it to
                 * map to the kernel dso.
                 */
                if (*remap_kernel && dso__kernel(dso) && !kmodule) {
                        *remap_kernel = false;
                        map__set_start(map, shdr->sh_addr + ref_reloc(kmap));
                        map__set_end(map, map__start(map) + shdr->sh_size);
                        map__set_pgoff(map, shdr->sh_offset);
                        map__set_mapping_type(map, MAPPING_TYPE__DSO);
                        /* Ensure maps are correctly ordered */
                        if (kmaps) {
                                int err;
                                struct map *tmp = map__get(map);

                                maps__remove(kmaps, map);
                                err = maps__insert(kmaps, map);
                                map__put(tmp);
                                if (err)
                                        return err;
                        }
                }

                /*
                 * The initial module mapping is based on
                 * /proc/modules mapped to offset zero.
                 * Overwrite it to map to the module dso.
                 */
                if (*remap_kernel && kmodule) {
                        *remap_kernel = false;
                        map__set_pgoff(map, shdr->sh_offset);
                }

                dso__put(*curr_dsop);
                *curr_dsop = dso__get(dso);
                return 0;
        }

        if (!kmap)
                return 0;

        /*
         * perf does not record module section addresses except for .text, but
         * some sections can use the same mapping as .text.
         */
        if (kmodule && adjust_kernel_syms && is_exe_text(shdr->sh_flags) &&
            shdr->sh_offset <= max_text_sh_offset) {
                dso__put(*curr_dsop);
                *curr_dsop = dso__get(dso);
                return 0;
        }

        snprintf(dso_name, sizeof(dso_name), "%s%s", dso__short_name(dso), section_name);

        curr_map = maps__find_by_name(kmaps, dso_name);
        if (curr_map == NULL) {
                u64 start = sym->st_value;

                if (kmodule)
                        start += map__start(map) + shdr->sh_offset;

                curr_dso = dso__new(dso_name);
                if (curr_dso == NULL)
                        return -1;
                dso__set_kernel(curr_dso, dso__kernel(dso));
                RC_CHK_ACCESS(curr_dso)->long_name = dso__long_name(dso);
                RC_CHK_ACCESS(curr_dso)->long_name_len = dso__long_name_len(dso);
                dso__set_binary_type(curr_dso, dso__binary_type(dso));
                dso__set_adjust_symbols(curr_dso, dso__adjust_symbols(dso));
                curr_map = map__new2(start, curr_dso);
                if (curr_map == NULL) {
                        dso__put(curr_dso);
                        return -1;
                }
                if (dso__kernel(curr_dso))
                        map__kmap(curr_map)->kmaps = kmaps;

                if (adjust_kernel_syms) {
                        map__set_start(curr_map, shdr->sh_addr + ref_reloc(kmap));
                        map__set_end(curr_map, map__start(curr_map) + shdr->sh_size);
                        map__set_pgoff(curr_map, shdr->sh_offset);
                } else {
                        map__set_mapping_type(curr_map, MAPPING_TYPE__IDENTITY);
                }
                dso__set_symtab_type(curr_dso, dso__symtab_type(dso));
                if (maps__insert(kmaps, curr_map)) {
                        dso__put(curr_dso);
                        map__put(curr_map);
                        return -1;
                }
                dsos__add(&maps__machine(kmaps)->dsos, curr_dso);
                dso__set_loaded(curr_dso);
                dso__put(*curr_dsop);
                *curr_dsop = curr_dso;
        } else {
                dso__put(*curr_dsop);
                *curr_dsop = dso__get(map__dso(curr_map));
        }
        map__put(curr_map);

        return 0;
}

static int
dso__load_sym_internal(struct dso *dso, struct map *map, struct symsrc *syms_ss,
                       struct symsrc *runtime_ss, int kmodule, int dynsym)
{
        struct kmap *kmap = dso__kernel(dso) ? map__kmap(map) : NULL;
        struct maps *kmaps = kmap ? map__kmaps(map) : NULL;
        struct dso *curr_dso = NULL;
        Elf_Data *symstrs, *secstrs, *secstrs_run, *secstrs_sym;
        uint32_t nr_syms;
        uint32_t idx;
        GElf_Ehdr ehdr;
        GElf_Shdr shdr;
        GElf_Shdr tshdr;
        Elf_Data *syms, *opddata = NULL;
        GElf_Sym sym;
        Elf_Scn *sec, *sec_strndx;
        Elf *elf;
        int nr = 0;
        bool remap_kernel = false, adjust_kernel_syms = false;
        u64 max_text_sh_offset = 0;

        if (kmap && !kmaps)
                return -1;

        elf = syms_ss->elf;
        ehdr = syms_ss->ehdr;
        if (dynsym) {
                sec  = syms_ss->dynsym;
                shdr = syms_ss->dynshdr;
        } else {
                sec =  syms_ss->symtab;
                shdr = syms_ss->symshdr;
        }

        if (elf_section_by_name(runtime_ss->elf, &runtime_ss->ehdr, &tshdr,
                                ".text", NULL)) {
                dso__set_text_offset(dso, tshdr.sh_addr - tshdr.sh_offset);
                dso__set_text_end(dso, tshdr.sh_offset + tshdr.sh_size);
        }

        if (runtime_ss->opdsec)
                opddata = elf_rawdata(runtime_ss->opdsec, NULL);

        syms = elf_getdata(sec, NULL);
        if (syms == NULL)
                goto out_elf_end;

        sec = elf_getscn(elf, shdr.sh_link);
        if (sec == NULL)
                goto out_elf_end;

        symstrs = elf_getdata(sec, NULL);
        if (symstrs == NULL)
                goto out_elf_end;

        sec_strndx = elf_getscn(runtime_ss->elf, runtime_ss->ehdr.e_shstrndx);
        if (sec_strndx == NULL)
                goto out_elf_end;

        secstrs_run = elf_getdata(sec_strndx, NULL);
        if (secstrs_run == NULL)
                goto out_elf_end;

        sec_strndx = elf_getscn(elf, ehdr.e_shstrndx);
        if (sec_strndx == NULL)
                goto out_elf_end;

        secstrs_sym = elf_getdata(sec_strndx, NULL);
        if (secstrs_sym == NULL)
                goto out_elf_end;

        nr_syms = shdr.sh_size / shdr.sh_entsize;

        memset(&sym, 0, sizeof(sym));

        /*
         * The kernel relocation symbol is needed in advance in order to adjust
         * kernel maps correctly.
         */
        if (ref_reloc_sym_not_found(kmap)) {
                elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) {
                        const char *elf_name = elf_sym__name(&sym, symstrs);

                        if (strcmp(elf_name, kmap->ref_reloc_sym->name))
                                continue;
                        kmap->ref_reloc_sym->unrelocated_addr = sym.st_value;
                        map__set_reloc(map, kmap->ref_reloc_sym->addr - kmap->ref_reloc_sym->unrelocated_addr);
                        break;
                }
        }

        /*
         * Handle any relocation of vdso necessary because older kernels
         * attempted to prelink vdso to its virtual address.
         */
        if (dso__is_vdso(dso))
                map__set_reloc(map, map__start(map) - dso__text_offset(dso));

        dso__set_adjust_symbols(dso, runtime_ss->adjust_symbols || ref_reloc(kmap));
        /*
         * Initial kernel and module mappings do not map to the dso.
         * Flag the fixups.
         */
        if (dso__kernel(dso)) {
                remap_kernel = true;
                adjust_kernel_syms = dso__adjust_symbols(dso);
        }

        if (kmodule && adjust_kernel_syms)
                max_text_sh_offset = max_text_section(runtime_ss->elf, &runtime_ss->ehdr);

        curr_dso = dso__get(dso);
        elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) {
                struct symbol *f;
                const char *elf_name = elf_sym__name(&sym, symstrs);
                char *demangled = NULL;
                int is_label = elf_sym__is_label(&sym);
                const char *section_name;
                bool used_opd = false;

                if (!is_label && !elf_sym__filter(&sym))
                        continue;

                /* Reject ARM ELF "mapping symbols": these aren't unique and
                 * don't identify functions, so will confuse the profile
                 * output: */
                if (ehdr.e_machine == EM_ARM || ehdr.e_machine == EM_AARCH64) {
                        if (elf_name[0] == '$' && strchr("adtx", elf_name[1])
                            && (elf_name[2] == '\0' || elf_name[2] == '.'))
                                continue;
                }

                /* Reject RISCV ELF "mapping symbols" */
                if (ehdr.e_machine == EM_RISCV) {
                        if (elf_name[0] == '$' && strchr("dx", elf_name[1]))
                                continue;
                }

                if (runtime_ss->opdsec && sym.st_shndx == runtime_ss->opdidx) {
                        u32 offset = sym.st_value - syms_ss->opdshdr.sh_addr;
                        u64 *opd = opddata->d_buf + offset;
                        sym.st_value = DSO__SWAP(dso, u64, *opd);
                        sym.st_shndx = elf_addr_to_index(runtime_ss->elf,
                                        sym.st_value);
                        used_opd = true;
                }

                /*
                 * When loading symbols in a data mapping, ABS symbols (which
                 * has a value of SHN_ABS in its st_shndx) failed at
                 * elf_getscn().  And it marks the loading as a failure so
                 * already loaded symbols cannot be fixed up.
                 *
                 * I'm not sure what should be done. Just ignore them for now.
                 * - Namhyung Kim
                 */
                if (sym.st_shndx == SHN_ABS)
                        continue;

                sec = elf_getscn(syms_ss->elf, sym.st_shndx);
                if (!sec)
                        goto out_elf_end;

                gelf_getshdr(sec, &shdr);

                /*
                 * If the attribute bit SHF_ALLOC is not set, the section
                 * doesn't occupy memory during process execution.
                 * E.g. ".gnu.warning.*" section is used by linker to generate
                 * warnings when calling deprecated functions, the symbols in
                 * the section aren't loaded to memory during process execution,
                 * so skip them.
                 */
                if (!(shdr.sh_flags & SHF_ALLOC))
                        continue;

                secstrs = secstrs_sym;

                /*
                 * We have to fallback to runtime when syms' section header has
                 * NOBITS set. NOBITS results in file offset (sh_offset) not
                 * being incremented. So sh_offset used below has different
                 * values for syms (invalid) and runtime (valid).
                 */
                if (shdr.sh_type == SHT_NOBITS) {
                        sec = elf_getscn(runtime_ss->elf, sym.st_shndx);
                        if (!sec)
                                goto out_elf_end;

                        gelf_getshdr(sec, &shdr);
                        secstrs = secstrs_run;
                }

                if (is_label && !elf_sec__filter(&shdr, secstrs))
                        continue;

                section_name = elf_sec__name(&shdr, secstrs);

                /* On ARM, symbols for thumb functions have 1 added to
                 * the symbol address as a flag - remove it */
                if ((ehdr.e_machine == EM_ARM) &&
                    (GELF_ST_TYPE(sym.st_info) == STT_FUNC) &&
                    (sym.st_value & 1))
                        --sym.st_value;

                if (dso__kernel(dso)) {
                        if (dso__process_kernel_symbol(dso, map, &sym, &shdr,
                                                       kmaps, kmap, &curr_dso,
                                                       section_name,
                                                       adjust_kernel_syms,
                                                       kmodule,
                                                       &remap_kernel,
                                                       max_text_sh_offset))
                                goto out_elf_end;
                } else if ((used_opd && runtime_ss->adjust_symbols) ||
                           (!used_opd && syms_ss->adjust_symbols)) {
                        GElf_Phdr phdr;

                        if (elf_read_program_header(runtime_ss->elf,
                                                    (u64)sym.st_value, &phdr)) {
                                pr_debug4("%s: failed to find program header for "
                                           "symbol: %s st_value: %#" PRIx64 "\n",
                                           __func__, elf_name, (u64)sym.st_value);
                                pr_debug4("%s: adjusting symbol: st_value: %#" PRIx64 " "
                                        "sh_addr: %#" PRIx64 " sh_offset: %#" PRIx64 "\n",
                                        __func__, (u64)sym.st_value, (u64)shdr.sh_addr,
                                        (u64)shdr.sh_offset);
                                /*
                                 * Fail to find program header, let's rollback
                                 * to use shdr.sh_addr and shdr.sh_offset to
                                 * calibrate symbol's file address, though this
                                 * is not necessary for normal C ELF file, we
                                 * still need to handle java JIT symbols in this
                                 * case.
                                 */
                                sym.st_value -= shdr.sh_addr - shdr.sh_offset;
                        } else {
                                pr_debug4("%s: adjusting symbol: st_value: %#" PRIx64 " "
                                        "p_vaddr: %#" PRIx64 " p_offset: %#" PRIx64 "\n",
                                        __func__, (u64)sym.st_value, (u64)phdr.p_vaddr,
                                        (u64)phdr.p_offset);
                                sym.st_value -= phdr.p_vaddr - phdr.p_offset;
                        }
                }

                demangled = dso__demangle_sym(dso, kmodule, elf_name);
                if (demangled != NULL)
                        elf_name = demangled;

                f = symbol__new(sym.st_value, sym.st_size,
                                GELF_ST_BIND(sym.st_info),
                                GELF_ST_TYPE(sym.st_info), elf_name);
                free(demangled);
                if (!f)
                        goto out_elf_end;

                arch__sym_update(f, &sym);

                __symbols__insert(dso__symbols(curr_dso), f, dso__kernel(dso));
                nr++;
        }
        dso__put(curr_dso);

        /*
         * For misannotated, zeroed, ASM function sizes.
         */
        if (nr > 0) {
                symbols__fixup_end(dso__symbols(dso), false);
                symbols__fixup_duplicate(dso__symbols(dso));
                if (kmap) {
                        /*
                         * We need to fixup this here too because we create new
                         * maps here, for things like vsyscall sections.
                         */
                        maps__fixup_end(kmaps);
                }
        }
        return nr;
out_elf_end:
        dso__put(curr_dso);
        return -1;
}

int dso__load_sym(struct dso *dso, struct map *map, struct symsrc *syms_ss,
                  struct symsrc *runtime_ss, int kmodule)
{
        int nr = 0;
        int err = -1;

        dso__set_symtab_type(dso, syms_ss->type);
        dso__set_is_64_bit(dso, syms_ss->is_64_bit);
        dso__set_rel(dso, syms_ss->ehdr.e_type == ET_REL);

        /*
         * Modules may already have symbols from kallsyms, but those symbols
         * have the wrong values for the dso maps, so remove them.
         */
        if (kmodule && syms_ss->symtab)
                symbols__delete(dso__symbols(dso));

        if (!syms_ss->symtab) {
                /*
                 * If the vmlinux is stripped, fail so we will fall back
                 * to using kallsyms. The vmlinux runtime symbols aren't
                 * of much use.
                 */
                if (dso__kernel(dso))
                        return err;
        } else  {
                err = dso__load_sym_internal(dso, map, syms_ss, runtime_ss,
                                             kmodule, 0);
                if (err < 0)
                        return err;
                nr = err;
        }

        if (syms_ss->dynsym) {
                err = dso__load_sym_internal(dso, map, syms_ss, runtime_ss,
                                             kmodule, 1);
                if (err < 0)
                        return err;
                nr += err;
        }

        /*
         * The .gnu_debugdata is a special situation: it contains a symbol
         * table, but the runtime file may also contain dynsym entries which are
         * not present there. We need to load both.
         */
        if (syms_ss->type == DSO_BINARY_TYPE__GNU_DEBUGDATA && runtime_ss->dynsym) {
                err = dso__load_sym_internal(dso, map, runtime_ss, runtime_ss,
                                             kmodule, 1);
                if (err < 0)
                        return err;
                nr += err;
        }

        return nr;
}

static int elf_read_maps(Elf *elf, bool exe, mapfn_t mapfn, void *data)
{
        GElf_Phdr phdr;
        size_t i, phdrnum;
        int err;
        u64 sz;

        if (elf_getphdrnum(elf, &phdrnum))
                return -1;

        for (i = 0; i < phdrnum; i++) {
                if (gelf_getphdr(elf, i, &phdr) == NULL)
                        return -1;
                if (phdr.p_type != PT_LOAD)
                        continue;
                if (exe) {
                        if (!(phdr.p_flags & PF_X))
                                continue;
                } else {
                        if (!(phdr.p_flags & PF_R))
                                continue;
                }
                sz = min(phdr.p_memsz, phdr.p_filesz);
                if (!sz)
                        continue;
                err = mapfn(phdr.p_vaddr, sz, phdr.p_offset, data);
                if (err)
                        return err;
        }
        return 0;
}

int file__read_maps(int fd, bool exe, mapfn_t mapfn, void *data,
                    bool *is_64_bit)
{
        int err;
        Elf *elf;

        elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
        if (elf == NULL)
                return -1;

        if (is_64_bit)
                *is_64_bit = (gelf_getclass(elf) == ELFCLASS64);

        err = elf_read_maps(elf, exe, mapfn, data);

        elf_end(elf);
        return err;
}

enum dso_type dso__type_fd(int fd)
{
        enum dso_type dso_type = DSO__TYPE_UNKNOWN;
        GElf_Ehdr ehdr;
        Elf_Kind ek;
        Elf *elf;

        elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
        if (elf == NULL)
                goto out;

        ek = elf_kind(elf);
        if (ek != ELF_K_ELF)
                goto out_end;

        if (gelf_getclass(elf) == ELFCLASS64) {
                dso_type = DSO__TYPE_64BIT;
                goto out_end;
        }

        if (gelf_getehdr(elf, &ehdr) == NULL)
                goto out_end;

        if (ehdr.e_machine == EM_X86_64)
                dso_type = DSO__TYPE_X32BIT;
        else
                dso_type = DSO__TYPE_32BIT;
out_end:
        elf_end(elf);
out:
        return dso_type;
}

static int copy_bytes(int from, off_t from_offs, int to, off_t to_offs, u64 len)
{
        ssize_t r;
        size_t n;
        int err = -1;
        char *buf = malloc(page_size);

        if (buf == NULL)
                return -1;

        if (lseek(to, to_offs, SEEK_SET) != to_offs)
                goto out;

        if (lseek(from, from_offs, SEEK_SET) != from_offs)
                goto out;

        while (len) {
                n = page_size;
                if (len < n)
                        n = len;
                /* Use read because mmap won't work on proc files */
                r = read(from, buf, n);
                if (r < 0)
                        goto out;
                if (!r)
                        break;
                n = r;
                r = write(to, buf, n);
                if (r < 0)
                        goto out;
                if ((size_t)r != n)
                        goto out;
                len -= n;
        }

        err = 0;
out:
        free(buf);
        return err;
}

struct kcore {
        int fd;
        int elfclass;
        Elf *elf;
        GElf_Ehdr ehdr;
};

static int kcore__open(struct kcore *kcore, const char *filename)
{
        GElf_Ehdr *ehdr;

        kcore->fd = open(filename, O_RDONLY);
        if (kcore->fd == -1)
                return -1;

        kcore->elf = elf_begin(kcore->fd, ELF_C_READ, NULL);
        if (!kcore->elf)
                goto out_close;

        kcore->elfclass = gelf_getclass(kcore->elf);
        if (kcore->elfclass == ELFCLASSNONE)
                goto out_end;

        ehdr = gelf_getehdr(kcore->elf, &kcore->ehdr);
        if (!ehdr)
                goto out_end;

        return 0;

out_end:
        elf_end(kcore->elf);
out_close:
        close(kcore->fd);
        return -1;
}

static int kcore__init(struct kcore *kcore, char *filename, int elfclass,
                       bool temp)
{
        kcore->elfclass = elfclass;

        if (temp)
                kcore->fd = mkstemp(filename);
        else
                kcore->fd = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0400);
        if (kcore->fd == -1)
                return -1;

        kcore->elf = elf_begin(kcore->fd, ELF_C_WRITE, NULL);
        if (!kcore->elf)
                goto out_close;

        if (!gelf_newehdr(kcore->elf, elfclass))
                goto out_end;

        memset(&kcore->ehdr, 0, sizeof(GElf_Ehdr));

        return 0;

out_end:
        elf_end(kcore->elf);
out_close:
        close(kcore->fd);
        unlink(filename);
        return -1;
}

static void kcore__close(struct kcore *kcore)
{
        elf_end(kcore->elf);
        close(kcore->fd);
}

static int kcore__copy_hdr(struct kcore *from, struct kcore *to, size_t count)
{
        GElf_Ehdr *ehdr = &to->ehdr;
        GElf_Ehdr *kehdr = &from->ehdr;

        memcpy(ehdr->e_ident, kehdr->e_ident, EI_NIDENT);
        ehdr->e_type      = kehdr->e_type;
        ehdr->e_machine   = kehdr->e_machine;
        ehdr->e_version   = kehdr->e_version;
        ehdr->e_entry     = 0;
        ehdr->e_shoff     = 0;
        ehdr->e_flags     = kehdr->e_flags;
        ehdr->e_phnum     = count;
        ehdr->e_shentsize = 0;
        ehdr->e_shnum     = 0;
        ehdr->e_shstrndx  = 0;

        if (from->elfclass == ELFCLASS32) {
                ehdr->e_phoff     = sizeof(Elf32_Ehdr);
                ehdr->e_ehsize    = sizeof(Elf32_Ehdr);
                ehdr->e_phentsize = sizeof(Elf32_Phdr);
        } else {
                ehdr->e_phoff     = sizeof(Elf64_Ehdr);
                ehdr->e_ehsize    = sizeof(Elf64_Ehdr);
                ehdr->e_phentsize = sizeof(Elf64_Phdr);
        }

        if (!gelf_update_ehdr(to->elf, ehdr))
                return -1;

        if (!gelf_newphdr(to->elf, count))
                return -1;

        return 0;
}

static int kcore__add_phdr(struct kcore *kcore, int idx, off_t offset,
                           u64 addr, u64 len)
{
        GElf_Phdr phdr = {
                .p_type         = PT_LOAD,
                .p_flags        = PF_R | PF_W | PF_X,
                .p_offset       = offset,
                .p_vaddr        = addr,
                .p_paddr        = 0,
                .p_filesz       = len,
                .p_memsz        = len,
                .p_align        = page_size,
        };

        if (!gelf_update_phdr(kcore->elf, idx, &phdr))
                return -1;

        return 0;
}

static off_t kcore__write(struct kcore *kcore)
{
        return elf_update(kcore->elf, ELF_C_WRITE);
}

struct phdr_data {
        off_t offset;
        off_t rel;
        u64 addr;
        u64 len;
        struct list_head node;
        struct phdr_data *remaps;
};

struct sym_data {
        u64 addr;
        struct list_head node;
};

struct kcore_copy_info {
        u64 stext;
        u64 etext;
        u64 first_symbol;
        u64 last_symbol;
        u64 first_module;
        u64 first_module_symbol;
        u64 last_module_symbol;
        size_t phnum;
        struct list_head phdrs;
        struct list_head syms;
};

#define kcore_copy__for_each_phdr(k, p) \
        list_for_each_entry((p), &(k)->phdrs, node)

static struct phdr_data *phdr_data__new(u64 addr, u64 len, off_t offset)
{
        struct phdr_data *p = zalloc(sizeof(*p));

        if (p) {
                p->addr   = addr;
                p->len    = len;
                p->offset = offset;
        }

        return p;
}

static struct phdr_data *kcore_copy_info__addnew(struct kcore_copy_info *kci,
                                                 u64 addr, u64 len,
                                                 off_t offset)
{
        struct phdr_data *p = phdr_data__new(addr, len, offset);

        if (p)
                list_add_tail(&p->node, &kci->phdrs);

        return p;
}

static void kcore_copy__free_phdrs(struct kcore_copy_info *kci)
{
        struct phdr_data *p, *tmp;

        list_for_each_entry_safe(p, tmp, &kci->phdrs, node) {
                list_del_init(&p->node);
                free(p);
        }
}

static struct sym_data *kcore_copy__new_sym(struct kcore_copy_info *kci,
                                            u64 addr)
{
        struct sym_data *s = zalloc(sizeof(*s));

        if (s) {
                s->addr = addr;
                list_add_tail(&s->node, &kci->syms);
        }

        return s;
}

static void kcore_copy__free_syms(struct kcore_copy_info *kci)
{
        struct sym_data *s, *tmp;

        list_for_each_entry_safe(s, tmp, &kci->syms, node) {
                list_del_init(&s->node);
                free(s);
        }
}

static int kcore_copy__process_kallsyms(void *arg, const char *name, char type,
                                        u64 start)
{
        struct kcore_copy_info *kci = arg;

        if (!kallsyms__is_function(type))
                return 0;

        if (strchr(name, '[')) {
                if (!kci->first_module_symbol || start < kci->first_module_symbol)
                        kci->first_module_symbol = start;
                if (start > kci->last_module_symbol)
                        kci->last_module_symbol = start;
                return 0;
        }

        if (!kci->first_symbol || start < kci->first_symbol)
                kci->first_symbol = start;

        if (!kci->last_symbol || start > kci->last_symbol)
                kci->last_symbol = start;

        if (!strcmp(name, "_stext")) {
                kci->stext = start;
                return 0;
        }

        if (!strcmp(name, "_etext")) {
                kci->etext = start;
                return 0;
        }

        if (is_entry_trampoline(name) && !kcore_copy__new_sym(kci, start))
                return -1;

        return 0;
}

static int kcore_copy__parse_kallsyms(struct kcore_copy_info *kci,
                                      const char *dir)
{
        char kallsyms_filename[PATH_MAX];

        scnprintf(kallsyms_filename, PATH_MAX, "%s/kallsyms", dir);

        if (symbol__restricted_filename(kallsyms_filename, "/proc/kallsyms"))
                return -1;

        if (kallsyms__parse(kallsyms_filename, kci,
                            kcore_copy__process_kallsyms) < 0)
                return -1;

        return 0;
}

static int kcore_copy__process_modules(void *arg,
                                       const char *name __maybe_unused,
                                       u64 start, u64 size __maybe_unused)
{
        struct kcore_copy_info *kci = arg;

        if (!kci->first_module || start < kci->first_module)
                kci->first_module = start;

        return 0;
}

static int kcore_copy__parse_modules(struct kcore_copy_info *kci,
                                     const char *dir)
{
        char modules_filename[PATH_MAX];

        scnprintf(modules_filename, PATH_MAX, "%s/modules", dir);

        if (symbol__restricted_filename(modules_filename, "/proc/modules"))
                return -1;

        if (modules__parse(modules_filename, kci,
                           kcore_copy__process_modules) < 0)
                return -1;

        return 0;
}

static int kcore_copy__map(struct kcore_copy_info *kci, u64 start, u64 end,
                           u64 pgoff, u64 s, u64 e)
{
        u64 len, offset;

        if (s < start || s >= end)
                return 0;

        offset = (s - start) + pgoff;
        len = e < end ? e - s : end - s;

        return kcore_copy_info__addnew(kci, s, len, offset) ? 0 : -1;
}

static int kcore_copy__read_map(u64 start, u64 len, u64 pgoff, void *data)
{
        struct kcore_copy_info *kci = data;
        u64 end = start + len;
        struct sym_data *sdat;

        if (kcore_copy__map(kci, start, end, pgoff, kci->stext, kci->etext))
                return -1;

        if (kcore_copy__map(kci, start, end, pgoff, kci->first_module,
                            kci->last_module_symbol))
                return -1;

        list_for_each_entry(sdat, &kci->syms, node) {
                u64 s = round_down(sdat->addr, page_size);

                if (kcore_copy__map(kci, start, end, pgoff, s, s + len))
                        return -1;
        }

        return 0;
}

static int kcore_copy__read_maps(struct kcore_copy_info *kci, Elf *elf)
{
        if (elf_read_maps(elf, true, kcore_copy__read_map, kci) < 0)
                return -1;

        return 0;
}

static void kcore_copy__find_remaps(struct kcore_copy_info *kci)
{
        struct phdr_data *p, *k = NULL;
        u64 kend;

        if (!kci->stext)
                return;

        /* Find phdr that corresponds to the kernel map (contains stext) */
        kcore_copy__for_each_phdr(kci, p) {
                u64 pend = p->addr + p->len - 1;

                if (p->addr <= kci->stext && pend >= kci->stext) {
                        k = p;
                        break;
                }
        }

        if (!k)
                return;

        kend = k->offset + k->len;

        /* Find phdrs that remap the kernel */
        kcore_copy__for_each_phdr(kci, p) {
                u64 pend = p->offset + p->len;

                if (p == k)
                        continue;

                if (p->offset >= k->offset && pend <= kend)
                        p->remaps = k;
        }
}

static void kcore_copy__layout(struct kcore_copy_info *kci)
{
        struct phdr_data *p;
        off_t rel = 0;

        kcore_copy__find_remaps(kci);

        kcore_copy__for_each_phdr(kci, p) {
                if (!p->remaps) {
                        p->rel = rel;
                        rel += p->len;
                }
                kci->phnum += 1;
        }

        kcore_copy__for_each_phdr(kci, p) {
                struct phdr_data *k = p->remaps;

                if (k)
                        p->rel = p->offset - k->offset + k->rel;
        }
}

static int kcore_copy__calc_maps(struct kcore_copy_info *kci, const char *dir,
                                 Elf *elf)
{
        if (kcore_copy__parse_kallsyms(kci, dir))
                return -1;

        if (kcore_copy__parse_modules(kci, dir))
                return -1;

        if (kci->stext)
                kci->stext = round_down(kci->stext, page_size);
        else
                kci->stext = round_down(kci->first_symbol, page_size);

        if (kci->etext) {
                kci->etext = round_up(kci->etext, page_size);
        } else if (kci->last_symbol) {
                kci->etext = round_up(kci->last_symbol, page_size);
                kci->etext += page_size;
        }

        if (kci->first_module_symbol &&
            (!kci->first_module || kci->first_module_symbol < kci->first_module))
                kci->first_module = kci->first_module_symbol;

        kci->first_module = round_down(kci->first_module, page_size);

        if (kci->last_module_symbol) {
                kci->last_module_symbol = round_up(kci->last_module_symbol,
                                                   page_size);
                kci->last_module_symbol += page_size;
        }

        if (!kci->stext || !kci->etext)
                return -1;

        if (kci->first_module && !kci->last_module_symbol)
                return -1;

        if (kcore_copy__read_maps(kci, elf))
                return -1;

        kcore_copy__layout(kci);

        return 0;
}

static int kcore_copy__copy_file(const char *from_dir, const char *to_dir,
                                 const char *name)
{
        char from_filename[PATH_MAX];
        char to_filename[PATH_MAX];

        scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name);
        scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name);

        return copyfile_mode(from_filename, to_filename, 0400);
}

static int kcore_copy__unlink(const char *dir, const char *name)
{
        char filename[PATH_MAX];

        scnprintf(filename, PATH_MAX, "%s/%s", dir, name);

        return unlink(filename);
}

static int kcore_copy__compare_fds(int from, int to)
{
        char *buf_from;
        char *buf_to;
        ssize_t ret;
        size_t len;
        int err = -1;

        buf_from = malloc(page_size);
        buf_to = malloc(page_size);
        if (!buf_from || !buf_to)
                goto out;

        while (1) {
                /* Use read because mmap won't work on proc files */
                ret = read(from, buf_from, page_size);
                if (ret < 0)
                        goto out;

                if (!ret)
                        break;

                len = ret;

                if (readn(to, buf_to, len) != (int)len)
                        goto out;

                if (memcmp(buf_from, buf_to, len))
                        goto out;
        }

        err = 0;
out:
        free(buf_to);
        free(buf_from);
        return err;
}

static int kcore_copy__compare_files(const char *from_filename,
                                     const char *to_filename)
{
        int from, to, err = -1;

        from = open(from_filename, O_RDONLY);
        if (from < 0)
                return -1;

        to = open(to_filename, O_RDONLY);
        if (to < 0)
                goto out_close_from;

        err = kcore_copy__compare_fds(from, to);

        close(to);
out_close_from:
        close(from);
        return err;
}

static int kcore_copy__compare_file(const char *from_dir, const char *to_dir,
                                    const char *name)
{
        char from_filename[PATH_MAX];
        char to_filename[PATH_MAX];

        scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name);
        scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name);

        return kcore_copy__compare_files(from_filename, to_filename);
}

/**
 * kcore_copy - copy kallsyms, modules and kcore from one directory to another.
 * @from_dir: from directory
 * @to_dir: to directory
 *
 * This function copies kallsyms, modules and kcore files from one directory to
 * another.  kallsyms and modules are copied entirely.  Only code segments are
 * copied from kcore.  It is assumed that two segments suffice: one for the
 * kernel proper and one for all the modules.  The code segments are determined
 * from kallsyms and modules files.  The kernel map starts at _stext or the
 * lowest function symbol, and ends at _etext or the highest function symbol.
 * The module map starts at the lowest module address and ends at the highest
 * module symbol.  Start addresses are rounded down to the nearest page.  End
 * addresses are rounded up to the nearest page.  An extra page is added to the
 * highest kernel symbol and highest module symbol to, hopefully, encompass that
 * symbol too.  Because it contains only code sections, the resulting kcore is
 * unusual.  One significant peculiarity is that the mapping (start -> pgoff)
 * is not the same for the kernel map and the modules map.  That happens because
 * the data is copied adjacently whereas the original kcore has gaps.  Finally,
 * kallsyms file is compared with its copy to check that modules have not been
 * loaded or unloaded while the copies were taking place.
 *
 * Return: %0 on success, %-1 on failure.
 */
int kcore_copy(const char *from_dir, const char *to_dir)
{
        struct kcore kcore;
        struct kcore extract;
        int idx = 0, err = -1;
        off_t offset, sz;
        struct kcore_copy_info kci = { .stext = 0, };
        char kcore_filename[PATH_MAX];
        char extract_filename[PATH_MAX];
        struct phdr_data *p;

        INIT_LIST_HEAD(&kci.phdrs);
        INIT_LIST_HEAD(&kci.syms);

        if (kcore_copy__copy_file(from_dir, to_dir, "kallsyms"))
                return -1;

        if (kcore_copy__copy_file(from_dir, to_dir, "modules"))
                goto out_unlink_kallsyms;

        scnprintf(kcore_filename, PATH_MAX, "%s/kcore", from_dir);
        scnprintf(extract_filename, PATH_MAX, "%s/kcore", to_dir);

        if (kcore__open(&kcore, kcore_filename))
                goto out_unlink_modules;

        if (kcore_copy__calc_maps(&kci, from_dir, kcore.elf))
                goto out_kcore_close;

        if (kcore__init(&extract, extract_filename, kcore.elfclass, false))
                goto out_kcore_close;

        if (kcore__copy_hdr(&kcore, &extract, kci.phnum))
                goto out_extract_close;

        offset = gelf_fsize(extract.elf, ELF_T_EHDR, 1, EV_CURRENT) +
                 gelf_fsize(extract.elf, ELF_T_PHDR, kci.phnum, EV_CURRENT);
        offset = round_up(offset, page_size);

        kcore_copy__for_each_phdr(&kci, p) {
                off_t offs = p->rel + offset;

                if (kcore__add_phdr(&extract, idx++, offs, p->addr, p->len))
                        goto out_extract_close;
        }

        sz = kcore__write(&extract);
        if (sz < 0 || sz > offset)
                goto out_extract_close;

        kcore_copy__for_each_phdr(&kci, p) {
                off_t offs = p->rel + offset;

                if (p->remaps)
                        continue;
                if (copy_bytes(kcore.fd, p->offset, extract.fd, offs, p->len))
                        goto out_extract_close;
        }

        if (kcore_copy__compare_file(from_dir, to_dir, "kallsyms"))
                goto out_extract_close;

        err = 0;

out_extract_close:
        kcore__close(&extract);
        if (err)
                unlink(extract_filename);
out_kcore_close:
        kcore__close(&kcore);
out_unlink_modules:
        if (err)
                kcore_copy__unlink(to_dir, "modules");
out_unlink_kallsyms:
        if (err)
                kcore_copy__unlink(to_dir, "kallsyms");

        kcore_copy__free_phdrs(&kci);
        kcore_copy__free_syms(&kci);

        return err;
}

int kcore_extract__create(struct kcore_extract *kce)
{
        struct kcore kcore;
        struct kcore extract;
        size_t count = 1;
        int idx = 0, err = -1;
        off_t offset = page_size, sz;

        if (kcore__open(&kcore, kce->kcore_filename))
                return -1;

        strcpy(kce->extract_filename, PERF_KCORE_EXTRACT);
        if (kcore__init(&extract, kce->extract_filename, kcore.elfclass, true))
                goto out_kcore_close;

        if (kcore__copy_hdr(&kcore, &extract, count))
                goto out_extract_close;

        if (kcore__add_phdr(&extract, idx, offset, kce->addr, kce->len))
                goto out_extract_close;

        sz = kcore__write(&extract);
        if (sz < 0 || sz > offset)
                goto out_extract_close;

        if (copy_bytes(kcore.fd, kce->offs, extract.fd, offset, kce->len))
                goto out_extract_close;

        err = 0;

out_extract_close:
        kcore__close(&extract);
        if (err)
                unlink(kce->extract_filename);
out_kcore_close:
        kcore__close(&kcore);

        return err;
}

void kcore_extract__delete(struct kcore_extract *kce)
{
        unlink(kce->extract_filename);
}

#ifdef HAVE_GELF_GETNOTE_SUPPORT

static void sdt_adjust_loc(struct sdt_note *tmp, GElf_Addr base_off)
{
        if (!base_off)
                return;

        if (tmp->bit32)
                tmp->addr.a32[SDT_NOTE_IDX_LOC] =
                        tmp->addr.a32[SDT_NOTE_IDX_LOC] + base_off -
                        tmp->addr.a32[SDT_NOTE_IDX_BASE];
        else
                tmp->addr.a64[SDT_NOTE_IDX_LOC] =
                        tmp->addr.a64[SDT_NOTE_IDX_LOC] + base_off -
                        tmp->addr.a64[SDT_NOTE_IDX_BASE];
}

static void sdt_adjust_refctr(struct sdt_note *tmp, GElf_Addr base_addr,
                              GElf_Addr base_off)
{
        if (!base_off)
                return;

        if (tmp->bit32 && tmp->addr.a32[SDT_NOTE_IDX_REFCTR])
                tmp->addr.a32[SDT_NOTE_IDX_REFCTR] -= (base_addr - base_off);
        else if (tmp->addr.a64[SDT_NOTE_IDX_REFCTR])
                tmp->addr.a64[SDT_NOTE_IDX_REFCTR] -= (base_addr - base_off);
}

/**
 * populate_sdt_note : Parse raw data and identify SDT note
 * @elf: elf of the opened file
 * @data: raw data of a section with description offset applied
 * @len: note description size
 * @type: type of the note
 * @sdt_notes: List to add the SDT note
 *
 * Responsible for parsing the @data in section .note.stapsdt in @elf and
 * if its an SDT note, it appends to @sdt_notes list.
 */
static int populate_sdt_note(Elf **elf, const char *data, size_t len,
                             struct list_head *sdt_notes)
{
        const char *provider, *name, *args;
        struct sdt_note *tmp = NULL;
        GElf_Ehdr ehdr;
        GElf_Shdr shdr;
        int ret = -EINVAL;

        union {
                Elf64_Addr a64[NR_ADDR];
                Elf32_Addr a32[NR_ADDR];
        } buf;

        Elf_Data dst = {
                .d_buf = &buf, .d_type = ELF_T_ADDR, .d_version = EV_CURRENT,
                .d_size = gelf_fsize((*elf), ELF_T_ADDR, NR_ADDR, EV_CURRENT),
                .d_off = 0, .d_align = 0
        };
        Elf_Data src = {
                .d_buf = (void *) data, .d_type = ELF_T_ADDR,
                .d_version = EV_CURRENT, .d_size = dst.d_size, .d_off = 0,
                .d_align = 0
        };

        tmp = (struct sdt_note *)calloc(1, sizeof(struct sdt_note));
        if (!tmp) {
                ret = -ENOMEM;
                goto out_err;
        }

        INIT_LIST_HEAD(&tmp->note_list);

        if (len < dst.d_size + 3)
                goto out_free_note;

        /* Translation from file representation to memory representation */
        if (gelf_xlatetom(*elf, &dst, &src,
                          elf_getident(*elf, NULL)[EI_DATA]) == NULL) {
                pr_err("gelf_xlatetom : %s\n", elf_errmsg(-1));
                goto out_free_note;
        }

        /* Populate the fields of sdt_note */
        provider = data + dst.d_size;

        name = (const char *)memchr(provider, '\0', data + len - provider);
        if (name++ == NULL)
                goto out_free_note;

        tmp->provider = strdup(provider);
        if (!tmp->provider) {
                ret = -ENOMEM;
                goto out_free_note;
        }
        tmp->name = strdup(name);
        if (!tmp->name) {
                ret = -ENOMEM;
                goto out_free_prov;
        }

        args = memchr(name, '\0', data + len - name);

        /*
         * There is no argument if:
         * - We reached the end of the note;
         * - There is not enough room to hold a potential string;
         * - The argument string is empty or just contains ':'.
         */
        if (args == NULL || data + len - args < 2 ||
                args[1] == ':' || args[1] == '\0')
                tmp->args = NULL;
        else {
                tmp->args = strdup(++args);
                if (!tmp->args) {
                        ret = -ENOMEM;
                        goto out_free_name;
                }
        }

        if (gelf_getclass(*elf) == ELFCLASS32) {
                memcpy(&tmp->addr, &buf, 3 * sizeof(Elf32_Addr));
                tmp->bit32 = true;
        } else {
                memcpy(&tmp->addr, &buf, 3 * sizeof(Elf64_Addr));
                tmp->bit32 = false;
        }

        if (!gelf_getehdr(*elf, &ehdr)) {
                pr_debug("%s : cannot get elf header.\n", __func__);
                ret = -EBADF;
                goto out_free_args;
        }

        /* Adjust the prelink effect :
         * Find out the .stapsdt.base section.
         * This scn will help us to handle prelinking (if present).
         * Compare the retrieved file offset of the base section with the
         * base address in the description of the SDT note. If its different,
         * then accordingly, adjust the note location.
         */
        if (elf_section_by_name(*elf, &ehdr, &shdr, SDT_BASE_SCN, NULL))
                sdt_adjust_loc(tmp, shdr.sh_offset);

        /* Adjust reference counter offset */
        if (elf_section_by_name(*elf, &ehdr, &shdr, SDT_PROBES_SCN, NULL))
                sdt_adjust_refctr(tmp, shdr.sh_addr, shdr.sh_offset);

        list_add_tail(&tmp->note_list, sdt_notes);
        return 0;

out_free_args:
        zfree(&tmp->args);
out_free_name:
        zfree(&tmp->name);
out_free_prov:
        zfree(&tmp->provider);
out_free_note:
        free(tmp);
out_err:
        return ret;
}

/**
 * construct_sdt_notes_list : constructs a list of SDT notes
 * @elf : elf to look into
 * @sdt_notes : empty list_head
 *
 * Scans the sections in 'elf' for the section
 * .note.stapsdt. It, then calls populate_sdt_note to find
 * out the SDT events and populates the 'sdt_notes'.
 */
static int construct_sdt_notes_list(Elf *elf, struct list_head *sdt_notes)
{
        GElf_Ehdr ehdr;
        Elf_Scn *scn = NULL;
        Elf_Data *data;
        GElf_Shdr shdr;
        size_t shstrndx, next;
        GElf_Nhdr nhdr;
        size_t name_off, desc_off, offset;
        int ret = 0;

        if (gelf_getehdr(elf, &ehdr) == NULL) {
                ret = -EBADF;
                goto out_ret;
        }
        if (elf_getshdrstrndx(elf, &shstrndx) != 0) {
                ret = -EBADF;
                goto out_ret;
        }

        /* Look for the required section */
        scn = elf_section_by_name(elf, &ehdr, &shdr, SDT_NOTE_SCN, NULL);
        if (!scn) {
                ret = -ENOENT;
                goto out_ret;
        }

        if ((shdr.sh_type != SHT_NOTE) || (shdr.sh_flags & SHF_ALLOC)) {
                ret = -ENOENT;
                goto out_ret;
        }

        data = elf_getdata(scn, NULL);

        /* Get the SDT notes */
        for (offset = 0; (next = gelf_getnote(data, offset, &nhdr, &name_off,
                                              &desc_off)) > 0; offset = next) {
                if (nhdr.n_namesz == sizeof(SDT_NOTE_NAME) &&
                    !memcmp(data->d_buf + name_off, SDT_NOTE_NAME,
                            sizeof(SDT_NOTE_NAME))) {
                        /* Check the type of the note */
                        if (nhdr.n_type != SDT_NOTE_TYPE)
                                goto out_ret;

                        ret = populate_sdt_note(&elf, ((data->d_buf) + desc_off),
                                                nhdr.n_descsz, sdt_notes);
                        if (ret < 0)
                                goto out_ret;
                }
        }
        if (list_empty(sdt_notes))
                ret = -ENOENT;

out_ret:
        return ret;
}

/**
 * get_sdt_note_list : Wrapper to construct a list of sdt notes
 * @head : empty list_head
 * @target : file to find SDT notes from
 *
 * This opens the file, initializes
 * the ELF and then calls construct_sdt_notes_list.
 */
int get_sdt_note_list(struct list_head *head, const char *target)
{
        Elf *elf;
        int fd, ret;

        fd = open(target, O_RDONLY);
        if (fd < 0)
                return -EBADF;

        elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
        if (!elf) {
                ret = -EBADF;
                goto out_close;
        }
        ret = construct_sdt_notes_list(elf, head);
        elf_end(elf);
out_close:
        close(fd);
        return ret;
}

/**
 * cleanup_sdt_note_list : free the sdt notes' list
 * @sdt_notes: sdt notes' list
 *
 * Free up the SDT notes in @sdt_notes.
 * Returns the number of SDT notes free'd.
 */
int cleanup_sdt_note_list(struct list_head *sdt_notes)
{
        struct sdt_note *tmp, *pos;
        int nr_free = 0;

        list_for_each_entry_safe(pos, tmp, sdt_notes, note_list) {
                list_del_init(&pos->note_list);
                zfree(&pos->args);
                zfree(&pos->name);
                zfree(&pos->provider);
                free(pos);
                nr_free++;
        }
        return nr_free;
}

/**
 * sdt_notes__get_count: Counts the number of sdt events
 * @start: list_head to sdt_notes list
 *
 * Returns the number of SDT notes in a list
 */
int sdt_notes__get_count(struct list_head *start)
{
        struct sdt_note *sdt_ptr;
        int count = 0;

        list_for_each_entry(sdt_ptr, start, note_list)
                count++;
        return count;
}
#endif

void symbol__elf_init(void)
{
        elf_version(EV_CURRENT);
}