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/*

 * Copyright (c) 2008 Jiri Svoboda

 * All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 *

 * - Redistributions of source code must retain the above copyright

 *   notice, this list of conditions and the following disclaimer.

 * - 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.

 * - 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.

 */

/** @addtogroup rtld rtld

 * @brief

 * @{

 */

/**

 * @file

 */

#include <stdio.h>

#include <stdlib.h>

#include <unistd.h>

#include <fcntl.h>

#include <libadt/list.h>

#include <loader/pcb.h>

#include <rtld.h>

#include <dynamic.h>

#include <elf_load.h>

#include <rtld_arch.h>

#include <module.h>

/** (Eagerly) process all relocation tables in a module.

 *

 * Currently works as if LD_BIND_NOW was specified.

 */

void module_process_relocs(module_t *m)

{

    DPRINTF("module_process_relocs('%s')\n", m->dyn.soname);

    /* Do not relocate twice. */

    if (m->relocated) return;

    module_process_pre_arch(m);

    if (m->dyn.plt_rel == DT_REL) {

        DPRINTF("table type DT_REL\n");

        if (m->dyn.rel != NULL) {

            DPRINTF("non-empty\n");

            rel_table_process(m, m->dyn.rel, m->dyn.rel_sz);

        }

        /* FIXME: this seems wrong */

        if (m->dyn.jmp_rel != NULL) {

        DPRINTF("table type jmp-rel\n");

            DPRINTF("non-empty\n");

            rel_table_process(m, m->dyn.jmp_rel, m->dyn.plt_rel_sz);

        }

    } else { /* (m->dyn.plt_rel == DT_RELA) */

        DPRINTF("table type DT_RELA\n");

        if (m->dyn.rela != NULL) {

            DPRINTF("non-empty\n");

            rela_table_process(m, m->dyn.rela, m->dyn.rela_sz);

        }

    }

    m->relocated = true;

}

/** Find module structure by soname/pathname.

 *

 * Used primarily to see if a module has already been loaded.

 * Modules are compared according to their soname, i.e. possible

 * path components are ignored.

 */

module_t *module_find(char *name)

{

    link_t *head = &runtime_env->modules_head;

    link_t *cur;

    module_t *m;

    char *p, *soname;

    /*

     * If name contains slashes, treat it as a pathname and

     * construct soname by chopping off the path. Otherwise

     * treat it as soname.

     */

    p = strrchr(name, '/');

    soname = p ? (p + 1) : name;

    /* Traverse list of all modules. Not extremely fast, but simple */

    for (cur = head->next; cur != head; cur = cur->next) {

        m = list_get_instance(cur, module_t, modules_link);

        if (strcmp(m->dyn.soname, soname) == 0) {

            return m; /* Found */

        }

    }

    return NULL; /* Not found */

}

#define NAME_BUF_SIZE 64

/** Load a module.

 *

 * Currently this trivially tries to load '/<name>'.

 */

module_t *module_load(char *name)

{

    elf_info_t info;

    char name_buf[NAME_BUF_SIZE];

    module_t *m;

    int rc;

    m = malloc(sizeof(module_t));

    if (!m) {

        printf("malloc failed\n");

        exit(1);

    }

    if (strlen(name) > NAME_BUF_SIZE - 2) {

        printf("soname too long. increase NAME_BUF_SIZE\n");

        exit(1);

    }

    /* Prepend soname with '/lib/' */

    name_buf[0] = '/';

    strcpy(name_buf, "/lib/");

    strcpy(name_buf + 5, name);

    /* FIXME: need to real allocation of address space */

    m->bias = runtime_env->next_bias;

    runtime_env->next_bias += 0x100000;

    DPRINTF("filename:'%s'\n", name_buf);

    printf("load '%s' at 0x%x\n", name_buf, m->bias);

    rc = elf_load_file(name_buf, m->bias, ELDF_RW, &info);

    if (rc != EE_OK) {

        printf("Failed to load '%s'\n", name_buf);

        exit(1);

    }

    if (info.dynamic == NULL) {

        printf("Error: '%s' is not a dynamically-linked object.\n",

            name_buf);

        exit(1);

    }

    /* Pending relocation. */

    m->relocated = false;

    DPRINTF("parse dynamic section\n");

    /* Parse ELF .dynamic section. Store info to m->dyn. */

    dynamic_parse(info.dynamic, m->bias, &m->dyn);

    /* Insert into the list of loaded modules */

    list_append(&m->modules_link, &runtime_env->modules_head);

    return m;

}

/** Load all modules on which m (transitively) depends.

 */

void module_load_deps(module_t *m)

{

    elf_dyn_t *dp;

    char *dep_name;

    module_t *dm;

    size_t n, i;

    /* Count direct dependencies */

    dp = m->dyn.dynamic;

    n = 0;

    while (dp->d_tag != DT_NULL) {

        if (dp->d_tag == DT_NEEDED) ++n;

        ++dp;

    }

    /* Create an array of pointers to direct dependencies */

    m->n_deps = n;

    if (n == 0) {

        /* There are no dependencies, so we are done. */

        m->deps = NULL;

        return;

    }

    m->deps = malloc(n * sizeof(module_t *));

    if (!m->deps) {

        printf("malloc failed\n");

        exit(1);

    }

    i = 0; /* Current dependency index */

    dp = m->dyn.dynamic;

    while (dp->d_tag != DT_NULL) {

        if (dp->d_tag == DT_NEEDED) {

            dep_name = m->dyn.str_tab + dp->d_un.d_val;

            DPRINTF("%s needs %s\n", m->dyn.soname, dep_name);

            dm = module_find(dep_name);

            if (!dm) {

                dm = module_load(dep_name);

                module_load_deps(dm);

            }

            /* Save into deps table */

            m->deps[i++] = dm;

        }

        ++dp;

    }

}

/** Process relocations in modules.

 *

 * Processes relocations in @a start and all its dependencies.

 * Modules that have already been relocated are unaffected.

 *

 * @param   start   The module where to start from.

 */

void modules_process_relocs(module_t *start)

{

    link_t *head = &runtime_env->modules_head;

    link_t *cur;

    module_t *m;

    for (cur = head->next; cur != head; cur = cur->next) {

        m = list_get_instance(cur, module_t, modules_link);

        /* Skip rtld, since it has already been processed */

        if (m != &runtime_env->rtld) {

            module_process_relocs(m);

        }

    }

}

/** Clear BFS tags of all modules.

 */

void modules_untag(void)

{

    link_t *head = &runtime_env->modules_head;

    link_t *cur;

    module_t *m;

    for (cur = head->next; cur != head; cur = cur->next) {

        m = list_get_instance(cur, module_t, modules_link);

        m->bfs_tag = false;

    }

}

/** @}

 */