/*      $OpenBSD: library_subr.c,v 1.55 2023/04/27 12:27:56 robert Exp $ */

/*
 * Copyright (c) 2002 Dale Rahn
 * 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 <sys/queue.h>
#include <limits.h>
#include <dirent.h>

#include "util.h"
#include "resolve.h"
#include "dir.h"
#include "sod.h"

char * _dl_default_path[2] = { "/usr/lib", NULL };


/* STATIC DATA */
struct dlochld _dlopened_child_list;


/*
 * _dl_match_file()
 *
 * This function determines if a given name matches what is specified
 * in a struct sod. The major must match exactly, and the minor must
 * be same or larger.
 *
 * sodp is updated with the minor if this matches.
 */

int
_dl_match_file(struct sod *sodp, const char *name, int namelen)
{
        int match;
        struct sod lsod;
        const char *lname;

        lname = name;
        if (sodp->sod_library) {
                if (_dl_strncmp(name, "lib", 3))
                        return 0;
                lname += 3;
        }
        if (_dl_strncmp(lname, (char *)sodp->sod_name,
            _dl_strlen((char *)sodp->sod_name)))
                return 0;

        _dl_build_sod(name, &lsod);

        match = 0;
        if ((_dl_strcmp((char *)lsod.sod_name, (char *)sodp->sod_name) == 0) &&
            (lsod.sod_library == sodp->sod_library) &&
            ((sodp->sod_major == -1) || (sodp->sod_major == lsod.sod_major)) &&
            ((sodp->sod_minor == -1) ||
            (lsod.sod_minor >= sodp->sod_minor))) {
                match = 1;

                /* return version matched */
                sodp->sod_major = lsod.sod_major;
                sodp->sod_minor = lsod.sod_minor;
        }
        _dl_free((char *)lsod.sod_name);
        return match;
}

/*
 * _dl_cmp_sod()
 *
 * This function compares sod structs. The major must match exactly,
 * and the minor must be same or larger.
 *
 * sodp is updated with the minor if this matches.
 */

static int
_dl_cmp_sod(struct sod *sodp, const struct sod *lsod)
{
        int match;

        match = 1;
        if ((_dl_strcmp((char *)lsod->sod_name, (char *)sodp->sod_name) == 0) &&
            (lsod->sod_library == sodp->sod_library) &&
            ((sodp->sod_major == -1) || (sodp->sod_major == lsod->sod_major)) &&
            ((sodp->sod_minor == -1) ||
            (lsod->sod_minor >= sodp->sod_minor))) {
                match = 0;

                /* return version matched */
                sodp->sod_major = lsod->sod_major;
                sodp->sod_minor = lsod->sod_minor;
        }
        return match;
}

char _dl_hint_store[PATH_MAX];

char *
_dl_find_shlib(struct sod *sodp, char **searchpath, int nohints)
{
        char *hint, **pp;
        struct dirent *dp;
        int match, len;
        _dl_DIR *dd;
        struct sod tsod, bsod;          /* transient and best sod */

        /* if we are to search default directories, and hints
         * are not to be used, search the standard path from ldconfig
         * (_dl_hint_search_path) or use the default path
         */
        if (nohints)
                goto nohints;

        if (searchpath == NULL) {
                /* search 'standard' locations, find any match in the hints */
                hint = _dl_findhint((char *)sodp->sod_name, sodp->sod_major,
                    sodp->sod_minor, NULL);
                if (hint)
                        return hint;
        } else {
                /* search hints requesting matches for only
                 * the searchpath directories,
                 */
                for (pp = searchpath; *pp != NULL; pp++) {
                        hint = _dl_findhint((char *)sodp->sod_name,
                            sodp->sod_major, sodp->sod_minor, *pp);
                        if (hint != NULL)
                                return hint;
                }
        }

        /*
         * For each directory in the searchpath, read the directory
         * entries looking for a match to sod. filename compare is
         * done by _dl_match_file()
         */
nohints:
        if (searchpath == NULL) {
                if (_dl_hint_search_path != NULL)
                        searchpath = _dl_hint_search_path;
                else
                        searchpath = _dl_default_path;
        }
        _dl_memset(&bsod, 0, sizeof(bsod));
        for (pp = searchpath; *pp != NULL; pp++) {
                if ((dd = _dl_opendir(*pp)) != NULL) {
                        match = 0;
                        while ((dp = _dl_readdir(dd)) != NULL) {
                                tsod = *sodp;
                                if (_dl_match_file(&tsod, dp->d_name,
                                    dp->d_namlen)) {
                                        /*
                                         * When a match is found, tsod is
                                         * updated with the major+minor found.
                                         * This version is compared with the
                                         * largest so far (kept in bsod),
                                         * and saved if larger.
                                         */
                                        if (!match ||
                                            tsod.sod_major == -1 ||
                                            tsod.sod_major > bsod.sod_major ||
                                            ((tsod.sod_major ==
                                            bsod.sod_major) &&
                                            tsod.sod_minor > bsod.sod_minor)) {
                                                bsod = tsod;
                                                match = 1;
                                                len = _dl_strlcpy(
                                                    _dl_hint_store, *pp,
                                                    PATH_MAX);
                                                if (pp[0][len-1] != '/') {
                                                        _dl_hint_store[len] =
                                                            '/';
                                                        len++;
                                                }
                                                _dl_strlcpy(
                                                    &_dl_hint_store[len],
                                                    dp->d_name,
                                                    PATH_MAX-len);
                                                if (tsod.sod_major == -1)
                                                        break;
                                        }
                                }
                        }
                        _dl_closedir(dd);
                        if (match) {
                                *sodp = bsod;
                                return (_dl_hint_store);
                        }
                }
        }
        return NULL;
}

static elf_object_t *
_dl_lookup_object(const char *req_name, struct sod *req_sod)
{
        elf_object_t *object = _dl_objects;

        while (object) {
                char *soname;

                if (_dl_cmp_sod(req_sod, &object->sod) == 0)
                        return(object);

                soname = (char *)object->Dyn.info[DT_SONAME];
                if (soname != NULL) {
                        if (_dl_strcmp(req_name, soname) == 0)
                                return(object);
                }

                object = object->next;
        }

        return(NULL);
}

void
_dl_handle_already_loaded(elf_object_t *object, int flags)
{
        object->obj_flags |= flags & DF_1_GLOBAL;
        if (_dl_loading_object == NULL)
                _dl_loading_object = object;
        if (object->load_object != _dl_objects &&
            object->load_object != _dl_loading_object) {
                _dl_link_grpref(object->load_object, _dl_loading_object);
        }
}

static elf_object_t *
_dl_find_loaded_shlib(const char *req_name, struct sod req_sod, int flags)
{
        elf_object_t *object;

        object = _dl_lookup_object(req_name, &req_sod);

        /* if not found retry with any minor */
        if (object == NULL && req_sod.sod_library && req_sod.sod_minor != -1) {
                short orig_minor = req_sod.sod_minor;
                req_sod.sod_minor = -1;
                object = _dl_lookup_object(req_name, &req_sod);

                if (object != NULL && req_sod.sod_minor < orig_minor)
                        _dl_printf("warning: lib%s.so.%d.%d: "
                            "minor version >= %d expected, "
                            "using it anyway\n",
                            req_sod.sod_name, req_sod.sod_major,
                            req_sod.sod_minor, orig_minor);
        }

        if (object)
                _dl_handle_already_loaded(object, flags);

        return (object);
}

/*
 *  Load a shared object. Search order is:
 *      First check loaded objects for a matching shlib, otherwise:
 *
 *      If the name contains a '/' use only the path preceding the
 *      library name and do not continue on to other methods if not
 *      found.
 *         search hints for match in path preceding library name
 *           this will only match specific library version.
 *         search path preceding library name
 *           this will find largest minor version in path provided
 *
 *      Otherwise, the name doesn't contain a '/':
 *      search hints for the specific library version, trying in turn
 *      paths from the following:
 *        - the LD_LIBRARY_PATH environment variable (if set)
 *        - the library's own DT_RUNPATH
 *        - if DT_RUNPATH wasn't set, then:
 *          - the library's own DT_RPATH
 *          - the executable's own DT_RPATH
 *        - the default search path set by ldconfig, or /usr/lib if unset
 *
 *      If the hints doesn't have an exact match, then we search
 *      that exact same list of directories again, looking for a
 *      lib with the correct major version.  If we find a match on
 *      the major, then we take the match *in that directory* which
 *      has the largest minor version
 */

elf_object_t *
_dl_load_shlib(const char *libname, elf_object_t *parent, int type, int flags,
    int nodelete)
{
        int try_any_minor, ignore_hints;
        struct sod sod, req_sod;
        elf_object_t *object = NULL;
        char *hint;

        try_any_minor = 0;
        ignore_hints = 0;

        if (_dl_strchr(libname, '/')) {
                char *paths[2];
                char *lpath, *lname;
                lpath = _dl_strdup(libname);
                if (lpath == NULL)
                        _dl_oom();
                lname = _dl_strrchr(lpath, '/');
                if (lname == NULL) {
                        _dl_free(lpath);
                        _dl_errno = DL_NOT_FOUND;
                        return (object);
                }
                *lname = '\0';
                lname++;
                if (*lname  == '\0') {
                        _dl_free(lpath);
                        _dl_errno = DL_NOT_FOUND;
                        return (object);
                }

                _dl_build_sod(lname, &sod);
                req_sod = sod;

                paths[0] = lpath;
                paths[1] = NULL;
fullpathagain:
                hint = _dl_find_shlib(&req_sod, paths, ignore_hints);
                if (hint != NULL)
                        goto fullpathdone;

                if (try_any_minor == 0) {
                        try_any_minor = 1;
                        ignore_hints = 1;
                        req_sod.sod_minor = -1;
                        goto fullpathagain;
                }
                _dl_errno = DL_NOT_FOUND;
fullpathdone:
                _dl_free(lpath);
                goto done;
        }

        _dl_build_sod(libname, &sod);
        req_sod = sod;

        object = _dl_find_loaded_shlib(libname, req_sod, flags);
        if (object) {
                _dl_free((char *)sod.sod_name);
                return (object);
        }

again:
        /* No '/' in name. Scan the known places, LD_LIBRARY_PATH first.  */
        if (_dl_libpath != NULL) {
                hint = _dl_find_shlib(&req_sod, _dl_libpath, ignore_hints);
                if (hint != NULL)
                        goto done;
        }

        /* Check DT_RUNPATH */
        if (parent->runpath != NULL) {
                hint = _dl_find_shlib(&req_sod, parent->runpath, ignore_hints);
                if (hint != NULL)
                        goto done;
        } else {
                /*
                 * If DT_RUNPATH wasn't set then first check DT_RPATH,
                 * followed by the main program's DT_RPATH.
                 */
                if (parent->rpath != NULL) {
                        hint = _dl_find_shlib(&req_sod, parent->rpath,
                            ignore_hints);
                        if (hint != NULL)
                                goto done;
                }
                if (parent != _dl_objects && _dl_objects->rpath != NULL) {
                        hint = _dl_find_shlib(&req_sod, _dl_objects->rpath,
                            ignore_hints);
                        if (hint != NULL)
                                goto done;
                }
        }

        /* check 'standard' locations */
        hint = _dl_find_shlib(&req_sod, NULL, ignore_hints);
        if (hint != NULL)
                goto done;

        if (try_any_minor == 0) {
                try_any_minor = 1;
                ignore_hints = 1;
                req_sod.sod_minor = -1;
                goto again;
        }
        _dl_errno = DL_NOT_FOUND;
done:
        if (hint != NULL) {
                if (req_sod.sod_minor < sod.sod_minor)
                        _dl_printf("warning: lib%s.so.%d.%d: "
                            "minor version >= %d expected, "
                            "using it anyway\n",
                            sod.sod_name, sod.sod_major,
                            req_sod.sod_minor, sod.sod_minor);
                object = _dl_tryload_shlib(hint, type, flags, nodelete);
        }
        _dl_free((char *)sod.sod_name);
        return(object);
}


void
_dl_link_dlopen(elf_object_t *dep)
{
        struct dep_node *n;

        dep->opencount++;

        if (OBJECT_DLREF_CNT(dep) > 1)
                return;

        n = _dl_malloc(sizeof *n);
        if (n == NULL)
                _dl_oom();

        n->data = dep;
        TAILQ_INSERT_TAIL(&_dlopened_child_list, n, next_sib);

        DL_DEB(("linking %s as dlopen()ed\n", dep->load_name));
}

static void
_dl_child_refcnt_decrement(elf_object_t *object)
{
        struct object_vector vec;
        int i;

        object->refcount--;
        if (OBJECT_REF_CNT(object) == 0)
                for (vec = object->child_vec, i = 0; i < vec.len; i++)
                        _dl_child_refcnt_decrement(vec.vec[i]);
}

void
_dl_notify_unload_shlib(elf_object_t *object)
{
        struct object_vector vec;
        struct dep_node *n;
        int i;

        if (OBJECT_REF_CNT(object) == 0)
                for (vec = object->child_vec, i = 0; i < vec.len; i++)
                        _dl_child_refcnt_decrement(vec.vec[i]);

        if (OBJECT_DLREF_CNT(object) == 0) {
                while ((n = TAILQ_FIRST(&object->grpref_list)) != NULL) {
                        TAILQ_REMOVE(&object->grpref_list, n, next_sib);
                        n->data->grprefcount--;
                        _dl_notify_unload_shlib(n->data);
                        _dl_free(n);
                }
        }
}

void
_dl_unload_dlopen(void)
{
        struct dep_node *node;

        TAILQ_FOREACH_REVERSE(node, &_dlopened_child_list, dlochld, next_sib) {
                /* dont dlclose the main program */
                if (node->data == _dl_objects)
                        continue;

                while (node->data->opencount > 0) {
                        node->data->opencount--;
                        _dl_notify_unload_shlib(node->data);
                        _dl_run_all_dtors();
                }
        }
}

void
_dl_link_grpref(elf_object_t *load_group, elf_object_t *load_object)
{
        struct dep_node *n;

        n = _dl_malloc(sizeof *n);
        if (n == NULL)
                _dl_oom();
        n->data = load_group;
        TAILQ_INSERT_TAIL(&load_object->grpref_list, n, next_sib);
        load_group->grprefcount++;
}

void
_dl_link_child(elf_object_t *dep, elf_object_t *p)
{
        int i;

        i = p->child_vec.len++;
        if (i == p->child_vec.alloc)
                _dl_die("child appeared  %d > %d", p->child_vec.len,
                    p->child_vec.alloc);
        p->child_vec.vec[i] = dep;

        dep->refcount++;

        DL_DEB(("linking dep %s as child of %s\n", dep->load_name,
            p->load_name));
}

void
object_vec_grow(struct object_vector *vec, int more)
{
        vec->alloc += more;
        vec->vec = _dl_reallocarray(vec->vec, vec->alloc, sizeof(*vec->vec));
        if (vec->vec == NULL)
                _dl_oom();
}

/* Generation number of the current grpsym insertion/caching */
static unsigned int _dl_grpsym_gen = 0;

void
_dl_link_grpsym(elf_object_t *object)
{
        struct object_vector *vec;
        int len;

        if (object->grpsym_gen == _dl_grpsym_gen)
                return;
        object->grpsym_gen = _dl_grpsym_gen;

        vec = &_dl_loading_object->grpsym_vec;
        len = vec->len++;
        if (len >= vec->alloc)
                _dl_die("more grpsym than objects?!  %d > %d", vec->len,
                    vec->alloc);
        vec->vec[len] = object;
}

void
_dl_cache_grpsym_list_setup(elf_object_t *object)
{
        struct object_vector *vec;
        int next;

        _dl_grpsym_gen += 1;

        if (_dl_grpsym_gen == 0) {
                /*
                 * If the count rolls over, reset all counters so
                 * we don't get accidental collision.
                 */
                elf_object_t *walkobj;
                for (walkobj = _dl_objects;
                    walkobj != NULL;
                    walkobj = walkobj->next) {
                        walkobj->grpsym_gen = 0;
                }
                _dl_grpsym_gen = 1;
        }

        /*
         * grpsym_vec is a vector of all child libs of the
         * _dl_loading_object with no dups. The order is equivalent
         * to a breadth-first traversal of the child list without dups.
         */

        vec = &object->grpsym_vec;
        object_vec_grow(vec, object_count);
        next = 0;

        /* add first object manually */
        _dl_link_grpsym(object);

        while (next < vec->len) {
                struct object_vector child_vec;
                int i;

                child_vec = vec->vec[next++]->child_vec;
                for (i = 0; i < child_vec.len; i++)
                        _dl_link_grpsym(child_vec.vec[i]);
        }
}