/*      $OpenBSD: dlfcn.c,v 1.117 2024/01/22 02:08:31 deraadt Exp $ */

/*
 * Copyright (c) 1998 Per Fogelstrom, Opsycon AB
 *
 * 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.
 *
 * 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.
 *
 */

#define _DYN_LOADER

#include <sys/types.h>
#include <link.h>
#include <dlfcn.h>
#include <unistd.h>

#include "syscall.h"
#include "util.h"
#include "resolve.h"
#include "archdep.h"

int _dl_errno;

static int _dl_real_close(void *handle);
static lock_cb *_dl_thread_fnc = NULL;
static elf_object_t *obj_from_addr(const void *addr);

#define OK_FLAGS        (0 \
        | RTLD_TRACE    \
        | RTLD_LAZY     \
        | RTLD_NOW      \
        | RTLD_GLOBAL   \
        | RTLD_NODELETE \
        | RTLD_NOLOAD   \
        )

void *
dlopen(const char *libname, int flags)
{
        elf_object_t *object;
        lock_cb *cb;
        int failed = 0;
        int obj_flags;

        if (flags & ~OK_FLAGS) {
                _dl_errno = DL_INVALID_MODE;
                return NULL;
        }

        if (libname == NULL)
                return RTLD_DEFAULT;

        if ((flags & RTLD_TRACE) == RTLD_TRACE) {
                _dl_traceld = 1;
        }

        DL_DEB(("dlopen: loading: %s\n", libname));

        cb = _dl_thread_kern_stop();

        if (_dl_debug_map && _dl_debug_map->r_brk) {
                _dl_debug_map->r_state = RT_ADD;
                (*((void (*)(void))_dl_debug_map->r_brk))();
        }

        _dl_loading_object = NULL;

        obj_flags = (flags & RTLD_NOW ? DF_1_NOW : 0)
            | (flags & RTLD_GLOBAL ? DF_1_GLOBAL : 0)
            | (flags & RTLD_NOLOAD ? DF_1_NOOPEN : 0)
            ;
        object = _dl_load_shlib(libname, _dl_objects, OBJTYPE_DLO, obj_flags, 0);
        if (object == 0) {
                DL_DEB(("dlopen: failed to open %s\n", libname));
                failed = 1;
                goto loaded;
        }

        if (flags & RTLD_NODELETE) {
                object->obj_flags |= DF_1_NODELETE;
                object->nodelete = 1;
        }

        _dl_link_dlopen(object);

        if (OBJECT_REF_CNT(object) > 1) {
                _dl_handle_nodelete(object);

                /* if opened but grpsym_vec has not been filled in */
                if (object->grpsym_vec.len == 0)
                        _dl_cache_grpsym_list_setup(object);
                if (_dl_traceld) {
                        _dl_show_objects(object);
                        _dl_unload_shlib(object);
                        _dl_exit(0);
                }
                goto loaded;
        }

        /* this add_object should not be here, XXX */
        _dl_add_object(object);

        DL_DEB(("head [%s]\n", object->load_name));

        if ((failed = _dl_load_dep_libs(object, obj_flags, 0)) == 1) {
                _dl_real_close(object);
                object = NULL;
                _dl_errno = DL_CANT_LOAD_OBJ;
        } else {
                int err;
                DL_DEB(("tail %s\n", object->load_name));
                if (_dl_traceld) {
                        _dl_show_objects(object);
                        _dl_unload_shlib(object);
                        _dl_exit(0);
                }
                err = _dl_rtld(object);
                if (err != 0) {
                        _dl_real_close(object);
                        _dl_errno = DL_CANT_LOAD_OBJ;
                        object = NULL;
                        failed = 1;
                } else {
                        _dl_call_init(object);
                }
        }

loaded:
        _dl_loading_object = NULL;

        if (_dl_debug_map && _dl_debug_map->r_brk) {
                _dl_debug_map->r_state = RT_CONSISTENT;
                (*((void (*)(void))_dl_debug_map->r_brk))();
        }

        _dl_thread_kern_go(cb);

        DL_DEB(("dlopen: %s: done (%s).\n", libname,
            failed ? "failed" : "success"));

        return((void *)object);
}

void *
dlsym(void *handle, const char *name)
{
        elf_object_t    *object;
        elf_object_t    *dynobj;
        struct sym_res  sr;
        int             flags;
        Elf_Addr        addr;

        if (handle == NULL || handle == RTLD_NEXT ||
            handle == RTLD_SELF || handle == RTLD_DEFAULT) {
                void *retaddr;

                retaddr = __builtin_return_address(0);  /* __GNUC__ only */

                if ((object = obj_from_addr(retaddr)) == NULL) {
                        _dl_errno = DL_CANT_FIND_OBJ;
                        return(0);
                }

                if (handle == RTLD_NEXT)
                        flags = SYM_SEARCH_NEXT|SYM_PLT;
                else if (handle == RTLD_SELF)
                        flags = SYM_SEARCH_SELF|SYM_PLT;
                else if (handle == RTLD_DEFAULT)
                        flags = SYM_SEARCH_ALL|SYM_PLT;
                else
                        flags = SYM_DLSYM|SYM_PLT;

        } else {
                object = (elf_object_t *)handle;
                flags = SYM_DLSYM|SYM_PLT;

                dynobj = _dl_objects;
                while (dynobj && dynobj != object)
                        dynobj = dynobj->next;

                if (!dynobj || object != dynobj) {
                        _dl_errno = DL_INVALID_HANDLE;
                        return(0);
                }
        }

        sr = _dl_find_symbol(name, flags|SYM_NOWARNNOTFOUND, NULL, object);
        if (sr.sym == NULL) {
                DL_DEB(("dlsym: failed to find symbol %s\n", name));
                _dl_errno = DL_NO_SYMBOL;
                return NULL;
        }

        addr = sr.obj->obj_base + sr.sym->st_value;
#ifdef __hppa__
        if (ELF_ST_TYPE(sr.sym->st_info) == STT_FUNC)
                addr = _dl_md_plabel(addr, sr.obj->dyn.pltgot);
#endif
        DL_DEB(("dlsym: %s in %s: %p\n",
            name, object->load_name, (void *)addr));
        return (void *)addr;
}

int
dlctl(void *handle, int command, void *data)
{
        int retval;

        switch (command) {
        case DL_SETTHREADLCK:
                DL_DEB(("dlctl: _dl_thread_fnc set to %p\n", data));
                _dl_thread_fnc = data;
                retval = 0;
                break;
        case DL_SETBINDLCK:
                /* made superfluous by kbind */
                retval = 0;
                break;
        case DL_REFERENCE:
        {
                elf_object_t *obj;

                obj = obj_from_addr(data);
                if (obj == NULL) {
                        _dl_errno = DL_CANT_FIND_OBJ;
                        retval = -1;
                        break;
                }
                if ((obj->status & STAT_NODELETE) == 0) {
                        obj->opencount++;
                        obj->status |= STAT_NODELETE;
                }
                retval = 0;
                break;
        }
        case 0x20:
                _dl_show_objects(NULL);
                retval = 0;
                break;
        case 0x21:
        {
                struct object_vector vec;
                struct dep_node *n, *m;
                elf_object_t *obj;
                int i;

                _dl_printf("Load Groups:\n");

                TAILQ_FOREACH(n, &_dlopened_child_list, next_sib) {
                        obj = n->data;
                        _dl_printf("%s\n", obj->load_name);

                        _dl_printf("  children\n");
                        for (vec = obj->child_vec, i = 0; i < vec.len; i++)
                                _dl_printf("\t[%s]\n", vec.vec[i]->load_name);

                        _dl_printf("  grpref\n");
                        TAILQ_FOREACH(m, &obj->grpref_list, next_sib)
                                _dl_printf("\t[%s]\n", m->data->load_name);
                        _dl_printf("\n");
                }
                retval = 0;
                break;
        }
        default:
                _dl_errno = DL_INVALID_CTL;
                retval = -1;
                break;
        }
        return (retval);
}
__strong_alias(_dlctl,dlctl);

int
dlclose(void *handle)
{
        lock_cb *cb;
        int retval;

        if (handle == RTLD_DEFAULT)
                return 0;

        cb = _dl_thread_kern_stop();

        if (_dl_debug_map && _dl_debug_map->r_brk) {
                _dl_debug_map->r_state = RT_DELETE;
                (*((void (*)(void))_dl_debug_map->r_brk))();
        }

        retval = _dl_real_close(handle);

        if (_dl_debug_map && _dl_debug_map->r_brk) {
                _dl_debug_map->r_state = RT_CONSISTENT;
                (*((void (*)(void))_dl_debug_map->r_brk))();
        }
        _dl_thread_kern_go(cb);
        return (retval);
}

int
_dl_real_close(void *handle)
{
        elf_object_t    *object;
        elf_object_t    *dynobj;

        object = (elf_object_t *)handle;

        dynobj = _dl_objects;
        while (dynobj && dynobj != object)
                dynobj = dynobj->next;

        if (!dynobj || object != dynobj) {
                _dl_errno = DL_INVALID_HANDLE;
                return (1);
        }

        if (object->opencount == 0) {
                _dl_errno = DL_INVALID_HANDLE;
                return (1);
        }

        object->opencount--;
        _dl_notify_unload_shlib(object);
        _dl_run_all_dtors();
        _dl_unload_shlib(object);
        _dl_cleanup_objects();
        return (0);
}


/*
 * Return a character string describing the last dl... error occurred.
 */
char *
dlerror(void)
{
        char *errmsg;

        switch (_dl_errno) {
        case 0: /* NO ERROR */
                errmsg = NULL;
                break;
        case DL_NOT_FOUND:
                errmsg = "File not found";
                break;
        case DL_CANT_OPEN:
                errmsg = "Can't open file";
                break;
        case DL_NOT_ELF:
                errmsg = "File not an ELF object";
                break;
        case DL_CANT_OPEN_REF:
                errmsg = "Can't open referenced object";
                break;
        case DL_CANT_MMAP:
                errmsg = "Can't map ELF object";
                break;
        case DL_INVALID_HANDLE:
                errmsg = "Invalid handle";
                break;
        case DL_NO_SYMBOL:
                errmsg = "Unable to resolve symbol";
                break;
        case DL_INVALID_CTL:
                errmsg = "Invalid dlctl() command";
                break;
        case DL_NO_OBJECT:
                errmsg = "No shared object contains address";
                break;
        case DL_CANT_FIND_OBJ:
                errmsg = "Cannot determine caller's shared object";
                break;
        case DL_CANT_LOAD_OBJ:
                errmsg = "Cannot load specified object";
                break;
        case DL_INVALID_MODE:
                errmsg = "Invalid mode";
                break;
        default:
                errmsg = "Unknown error";
        }

        _dl_errno = 0;
        return (errmsg);
}

static void
_dl_tracefmt(int fd, elf_object_t *object, const char *fmt1, const char *fmt2,
    const char *objtypename)
{
        const char *fmt;
        int i;

        fmt = object->sod.sod_library ? fmt1 : fmt2;

        for (i = 0; fmt[i]; i++) {
                if (fmt[i] != '%' && fmt[i] != '\\') {
                        _dl_dprintf(fd, "%c", fmt[i]);
                        continue;
                }
                if (fmt[i] == '%') {
                        i++;
                        switch (fmt[i]) {
                        case '\0':
                                return;
                        case '%':
                                _dl_dprintf(fd, "%c", '%');
                                break;
                        case 'A':
                                _dl_dprintf(fd, "%s", _dl_traceprog ?
                                    _dl_traceprog : "");
                                break;
                        case 'a':
                                _dl_dprintf(fd, "%s", __progname);
                                break;
                        case 'e':
                                _dl_dprintf(fd, "%lX",
                                    (void *)(object->load_base +
                                    object->load_size));
                                break;
                        case 'g':
                                _dl_dprintf(fd, "%d", object->grprefcount);
                                break;
                        case 'm':
                                _dl_dprintf(fd, "%d", object->sod.sod_major);
                                break;
                        case 'n':
                                _dl_dprintf(fd, "%d", object->sod.sod_minor);
                                break;
                        case 'O':
                                _dl_dprintf(fd, "%d", object->opencount);
                                break;
                        case 'o':
                                _dl_dprintf(fd, "%s", object->sod.sod_name);
                                break;
                        case 'p':
                                _dl_dprintf(fd, "%s", object->load_name);
                                break;
                        case 'r':
                                _dl_dprintf(fd, "%d", object->refcount);
                                break;
                        case 't':
                                _dl_dprintf(fd, "%s", objtypename);
                                break;
                        case 'x':
                                _dl_dprintf(fd, "%lX", object->load_base);
                                break;
                        }
                }
                if (fmt[i] == '\\') {
                        i++;
                        switch (fmt[i]) {
                        case '\0':
                                return;
                        case 'n':
                                _dl_dprintf(fd, "%c", '\n');
                                break;
                        case 'r':
                                _dl_dprintf(fd, "%c", '\r');
                                break;
                        case 't':
                                _dl_dprintf(fd, "%c", '\t');
                                break;
                        default:
                                _dl_dprintf(fd, "%c", fmt[i]);
                                break;
                        }
                }
        }
}

void
_dl_show_objects(elf_object_t *trace)
{
        elf_object_t *object;
        char *objtypename;
        int outputfd;
        char *pad;
        const char *fmt1, *fmt2;

        object = _dl_objects;
        if (_dl_traceld)
                outputfd = STDOUT_FILENO;
        else
                outputfd = STDERR_FILENO;

        if (sizeof(long) == 8)
                pad = "        ";
        else
                pad = "";

        fmt1 = _dl_tracefmt1 ? _dl_tracefmt1 :
            "\t%x %e %t %O    %r   %g      %p\n";
        fmt2 = _dl_tracefmt2 ? _dl_tracefmt2 :
            "\t%x %e %t %O    %r   %g      %p\n";

        if (_dl_tracefmt1 == NULL && _dl_tracefmt2 == NULL)
                _dl_dprintf(outputfd, "\tStart   %s End     %s Type  Open Ref GrpRef Name\n",
                    pad, pad);

        if (trace != NULL) {
                for (; object != NULL; object = object->next) {
                        if (object == trace)
                                break;
                        if (object->obj_type == OBJTYPE_LDR) {
                                object = object->next;
                                break;
                        }
                }
        }

        for (; object != NULL; object = object->next) {
                switch (object->obj_type) {
                case OBJTYPE_LDR:
                        objtypename = "ld.so";
                        break;
                case OBJTYPE_EXE:
                        objtypename = "exe  ";
                        break;
                case OBJTYPE_LIB:
                        objtypename = "rlib ";
                        break;
                case OBJTYPE_DLO:
                        objtypename = "dlib ";
                        break;
                default:
                        objtypename = "?????";
                        break;
                }
                _dl_tracefmt(outputfd, object, fmt1, fmt2, objtypename);
        }
}

lock_cb *
_dl_thread_kern_stop(void)
{
        lock_cb *cb = _dl_thread_fnc;

        if (cb != NULL)
                (*cb)(0);
        return cb;
}

void
_dl_thread_kern_go(lock_cb *cb)
{
        if (cb != NULL)
                (*cb)(1);
}

int
dl_iterate_phdr(int (*callback)(struct dl_phdr_info *, size_t, void *data),
        void *data)
{
        elf_object_t *object;
        struct dl_phdr_info info;
        int retval = -1;

        for (object = _dl_objects; object != NULL; object = object->next) {
                if (object->phdrp == NULL)
                        continue;

                info.dlpi_addr = object->obj_base;
                info.dlpi_name = object->load_name;
                info.dlpi_phdr = object->phdrp;
                info.dlpi_phnum = object->phdrc;
                retval = callback(&info, sizeof (struct dl_phdr_info), data);
                if (retval)
                        break;
        }

        return retval;
}

static elf_object_t *
obj_from_addr(const void *addr)
{
        elf_object_t *dynobj;
        Elf_Phdr *phdrp;
        int phdrc;
        Elf_Addr start;
        int i;

        for (dynobj = _dl_objects; dynobj != NULL; dynobj = dynobj->next) {
                if (dynobj->phdrp == NULL)
                        continue;

                phdrp = dynobj->phdrp;
                phdrc = dynobj->phdrc;

                for (i = 0; i < phdrc; i++, phdrp++) {
                        if (phdrp->p_type == PT_LOAD) {
                                start = dynobj->obj_base + phdrp->p_vaddr;
                                if ((Elf_Addr)addr >= start &&
                                    (Elf_Addr)addr < start + phdrp->p_memsz)
                                        return dynobj;
                        }
                }
        }

        return NULL;
}

int
dladdr(const void *addr, Dl_info *info)
{
        const elf_object_t *object;
        const Elf_Sym *sym;
        void *symbol_addr;
        u_int32_t symoffset;

        object = obj_from_addr(addr);

        if (object == NULL) {
                _dl_errno = DL_NO_OBJECT;
                return 0;
        }

        info->dli_fname = (char *)object->load_name;
        info->dli_fbase = (void *)object->load_base;
        info->dli_sname = NULL;
        info->dli_saddr = NULL;

        /*
         * Walk the symbol list looking for the symbol whose address is
         * closest to the address sent in.
         */
        for (symoffset = 0; symoffset < object->nchains; symoffset++) {
                sym = object->dyn.symtab + symoffset;

                /*
                 * For skip the symbol if st_shndx is either SHN_UNDEF or
                 * SHN_COMMON.
                 */
                if (sym->st_shndx == SHN_UNDEF || sym->st_shndx == SHN_COMMON)
                        continue;

                /*
                 * If the symbol is greater than the specified address, or if
                 * it is further away from addr than the current nearest
                 * symbol, then reject it.
                 */
                symbol_addr = (void *)(object->obj_base + sym->st_value);
                if (symbol_addr > addr || symbol_addr < info->dli_saddr)
                        continue;

                /* Update our idea of the nearest symbol. */
                info->dli_sname = object->dyn.strtab + sym->st_name;
                info->dli_saddr = symbol_addr;

                /* Exact match? */
                if (info->dli_saddr == addr)
                        break;
        }

        return 1;
}