/* $NetBSD: nlist_elf32.c,v 1.19 2010/08/28 21:30:03 joerg Exp $ */

/*
 * Copyright (c) 1996 Christopher G. Demetriou
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *          This product includes software developed for the
 *          NetBSD Project.  See http://www.NetBSD.org/ for
 *          information about NetBSD.
 * 4. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 * 
 * <<Id: LICENSE,v 1.2 2000/06/14 15:57:33 cgd Exp>>
 */

#include <sys/cdefs.h>
#ifndef lint
__RCSID("$NetBSD: nlist_elf32.c,v 1.19 2010/08/28 21:30:03 joerg Exp $");
#endif /* not lint */

/* If not included by nlist_elf64.c, ELFSIZE won't be defined. */
#ifndef ELFSIZE
#define ELFSIZE         32
#endif

#include <sys/param.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <sys/sysctl.h>
#include <sys/ioctl.h>
#include <sys/ksyms.h>

#include <a.out.h>
#include <db.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <kvm.h>
#include <limits.h>
#include <paths.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "extern.h"

#if defined(NLIST_ELF32) || defined(NLIST_ELF64)
#include <sys/exec_elf.h>
#endif

#if (defined(NLIST_ELF32) && (ELFSIZE == 32)) || \
    (defined(NLIST_ELF64) && (ELFSIZE == 64))

typedef struct nlist NLIST;
#define _strx   n_un.n_strx
#define _name   n_un.n_name

#define badfmt(str)                                                     \
        do {                                                            \
                warnx("%s: %s: %s", kfile, str, strerror(EFTYPE));      \
                punt();                                                 \
        } while (0)

#define check(off, size)        ((off < 0) || (off + size > mappedsize))
#define BAD                     do { rv = -1; goto out; } while (0)
#define BADUNMAP                do { rv = -1; goto unmap; } while (0)

static const char *kfile;

int
ELFNAMEEND(create_knlist)(name, db)
        const char *name;
        DB *db;
{
        struct stat st;
        struct nlist nbuf;
        DBT key, data;
        char *mappedfile, *symname, *nsymname, *fsymname, *tmpcp, *strtab;
        size_t mappedsize, symnamesize, fsymnamesize;
        Elf_Ehdr *ehdrp;
        Elf_Shdr *shdrp, *symshdrp, *symstrshdrp;
        Elf_Sym *symp;
        Elf_Off shdr_off;
        Elf_Word shdr_size;
#if (ELFSIZE == 32)
        Elf32_Half nshdr;
#elif (ELFSIZE == 64)
        Elf64_Word nshdr;
#endif
        unsigned long i, nsyms;
        int fd, rv, malloced = 0, isksyms;

        rv = -1;
#ifdef __GNUC__
        /* fix compiler warnings */
        symshdrp = NULL;
        symstrshdrp = NULL;
#endif

        /*
         * Open and map the whole file.  If we can't open/stat it,
         * something bad is going on so we punt.
         */
        kfile = name;
        if ((fd = open(name, O_RDONLY, 0)) < 0) {
                warn("%s", kfile);
                punt();
        }
        if (fstat(fd, &st) < 0) {
                warn("%s", kfile);
                punt();
        }
        if (st.st_size > SIZE_T_MAX)
                BAD;


        /*
         * Map the file in its entirety.
         */
        mappedfile = MAP_FAILED;
        mappedsize = st.st_size;
        isksyms = S_ISCHR(st.st_mode) &&
            strncmp(name, _PATH_KSYMS, sizeof(_PATH_KSYMS)) == 0;

        if (mappedsize == 0) {
                /* if it's a character device, stat returns size 0 */
                if (!isksyms)
                        BAD;
        } else {
                mappedfile = mmap(NULL, mappedsize, PROT_READ,
                    MAP_PRIVATE|MAP_FILE, fd, 0);
        }

        /*
         * If mmap failed, try to read the file instead.
         */
        if (mappedfile == MAP_FAILED) {
                int allocsiz, readsz;

                if (isksyms != 0) {
                        if (ioctl(fd, KIOCGSIZE, &allocsiz) < 0)
                                BAD;
                        mappedsize = allocsiz;
                } else
                        allocsiz = mappedsize;

                if ((mappedfile = malloc(mappedsize)) == NULL)
                        BAD;
                malloced = 1;
                if ((readsz = read(fd, mappedfile, mappedsize)) < 0)
                        BADUNMAP;

                if (readsz != mappedsize) /* Sanity */
                        BADUNMAP;
        }
        /*
         * Make sure we can access the executable's header
         * directly, and make sure the recognize the executable
         * as an ELF binary.
         */
        if (check(0, sizeof *ehdrp))
                BADUNMAP;
        ehdrp = (Elf_Ehdr *)&mappedfile[0];

        if (memcmp(ehdrp->e_ident, ELFMAG, SELFMAG) != 0 ||
            ehdrp->e_ident[EI_CLASS] != ELFCLASS)
                BADUNMAP;

        switch (ehdrp->e_machine) {
        ELFDEFNNAME(MACHDEP_ID_CASES)

        default:
                BADUNMAP;
        }

        /*
         * We've recognized it as an ELF binary.  From here
         * on out, all errors are fatal.
         */

        /*
         * Find the symbol list and string table.
         */
        nshdr = ehdrp->e_shnum;
        shdr_off = ehdrp->e_shoff;
        shdr_size = ehdrp->e_shentsize * nshdr;

        if (check(shdr_off, shdr_size) ||
            (sizeof *shdrp != ehdrp->e_shentsize))
                badfmt("bogus section header table");
        shdrp = (Elf_Shdr *)&mappedfile[shdr_off];

        for (i = 0; i < nshdr; i++) {
                if (shdrp[i].sh_type == SHT_SYMTAB) {
                        symshdrp = &shdrp[i];
                        symstrshdrp = &shdrp[shdrp[i].sh_link];
                }
        }

        if (symshdrp == NULL)
                badfmt("no symbol section header found");
        if (symshdrp->sh_offset == 0)
                badfmt("stripped");
        if (check(symshdrp->sh_offset, symshdrp->sh_size))
                badfmt("bogus symbol section header");
        if (check(symstrshdrp->sh_offset, symstrshdrp->sh_size))
                badfmt("bogus symbol string section header");

        symp = (Elf_Sym *)&mappedfile[symshdrp->sh_offset];
        nsyms = symshdrp->sh_size / sizeof(*symp);
        strtab = &mappedfile[symstrshdrp->sh_offset];

        /*
         * Set up the data item, pointing to a nlist structure.
         * which we fill in for each symbol.
         */
        data.data = (u_char *)&nbuf;
        data.size = sizeof(nbuf);

        /*
         * Create a buffer (to be expanded later, if necessary)
         * to hold symbol names after we've added underscores
         * to them.
         */
        symnamesize = 1024;
        if ((symname = malloc(symnamesize)) == NULL) {
                warn("malloc");
                punt();
        }

        /*
         * Read each symbol and enter it into the database.
         */
        for (i = 0; i < nsyms; i++) {

                /*
                 * No symbol name; ignore this symbol.
                 */
                if (symp[i].st_name == 0)
                        continue;

                /*
                 * Find symbol name, copy it (with added underscore) to
                 * temporary buffer, and prepare the database key for
                 * insertion.
                 */
                fsymname = &strtab[symp[i].st_name];
                fsymnamesize = strlen(fsymname) + 1;
                while (symnamesize < fsymnamesize + 1) {
                        if ((nsymname = realloc(symname, symnamesize * 2)) == NULL) {
                                warn("malloc");
                                punt();
                        }
                        symname = nsymname;
                        symnamesize *= 2;
                }
                strlcpy(symname, "_", symnamesize);
                strlcat(symname, fsymname, symnamesize);

                key.data = symname;
                key.size = strlen((char *)key.data);

                /*
                 * Convert the symbol information into an nlist structure,
                 * as best we can.
                 */
                nbuf.n_value = symp[i].st_value;
                switch (ELFDEFNNAME(ST_TYPE)(symp[i].st_info)) {
                default:
                case STT_NOTYPE:
                        nbuf.n_type = N_UNDF;
                        break;
                case STT_OBJECT:
                        nbuf.n_type = N_DATA;
                        break;
                case STT_FUNC:
                        nbuf.n_type = N_TEXT;
                        break;
                case STT_FILE:
                        nbuf.n_type = N_FN;
                        break;
                }
                if (ELFDEFNNAME(ST_BIND)(symp[i].st_info) != STB_LOCAL)
                        nbuf.n_type |= N_EXT;
                nbuf.n_desc = 0;                                /* XXX */
                nbuf.n_other = 0;                               /* XXX */

                /*
                 * Enter the symbol into the database.
                 */
                if (db->put(db, &key, &data, 0)) {
                        warn("record enter");
                        punt();
                }

                /*
                 * If it's the kernel version string, we've gotta keep
                 * some extra data around.  Under a separate key,
                 * we enter the first line (i.e. up to the first newline,
                 * with the newline replaced by a NUL to terminate the
                 * entered string) of the version string.
                 */
                if (strcmp((char *)key.data, VRS_SYM) == 0) {
                        key.data = (u_char *)VRS_KEY;
                        key.size = sizeof(VRS_KEY) - 1;
                        /* Find the version string, relative to its section */
                        if (isksyms) {
                                /* reading from /dev/ksyms, use sysctl */
                                size_t sz;
                                int mib[2];
                                char *kv;

                                mib[0] = CTL_KERN;
                                mib[1] = KERN_VERSION;
                                if (sysctl(mib, 2, NULL, &sz, NULL, 0) == -1) {
                                        warn("sysctl version size");
                                        punt();
                                }
                                if ((kv = malloc(sz)) == NULL) {
                                        warn("malloc version string");
                                        punt();
                                }
                                if (sysctl(mib, 2, kv, &sz, NULL, 0) == -1) {
                                        warn("sysctl version string");
                                        punt();
                                }
                                data.data = kv;
                        } else
                                data.data = strdup(&mappedfile[nbuf.n_value -
                                    shdrp[symp[i].st_shndx].sh_addr +
                                    shdrp[symp[i].st_shndx].sh_offset]);
                        /* assumes newline terminates version. */
                        if ((tmpcp = strchr(data.data, '\n')) != NULL)
                                *tmpcp = '\0';
                        data.size = strlen((char *)data.data);

                        if (db->put(db, &key, &data, 0)) {
                                warn("record enter");
                                punt();
                        }

                        /* free pointer created by strdup(). */
                        free(data.data);

                        /* Restore to original values */
                        data.data = (u_char *)&nbuf;
                        data.size = sizeof(nbuf);
                }
        }

        rv = 0;

unmap:
        if (malloced)
                free(mappedfile);
        else
                munmap(mappedfile, mappedsize);
out:
        return (rv);
}

#endif