source: mainline/uspace/lib/c/generic/rtld/rtld.c@ 31ea2a7

/*
 * 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
 * @brief
 * @{
 */
/**
 * @file
 */

#include <errno.h>
#include <rtld/module.h>
#include <rtld/rtld.h>
#include <rtld/rtld_debug.h>
#include <stdlib.h>
#include <str.h>

rtld_t *runtime_env;
static rtld_t rt_env_static;

/** Initialize a minimal runtime linker environment for use in executables loaded directly by kernel. */
errno_t rtld_init_static(void)
{
        errno_t rc;

        runtime_env = &rt_env_static;
        list_initialize(&runtime_env->modules);
        list_initialize(&runtime_env->imodules);
        runtime_env->program = NULL;
        runtime_env->next_id = 1;

        rc = module_create_static_exec(runtime_env, NULL);
        if (rc != EOK)
                return rc;

        modules_process_tls(runtime_env);

        return EOK;
}

/** Initialize and process an executable, static or dynamic.
 *
 * @param p_info Program info
 * @return EOK on success or non-zero error code
 */
errno_t rtld_prog_process(elf_finfo_t *p_info, rtld_t **rre)
{
        rtld_t *env;
        module_t *prog;

        DPRINTF("Load program with rtld.\n");

        /* Allocate new RTLD environment to pass to the loaded program */
        env = calloc(1, sizeof(rtld_t));
        if (env == NULL)
                return ENOMEM;

        env->next_id = 1;

        prog = calloc(1, sizeof(module_t));
        if (prog == NULL) {
                free(env);
                return ENOMEM;
        }

        /*
         * First we need to process dynamic sections of the executable
         * program and insert it into the module graph.
         */

        if (p_info->dynamic) {
                DPRINTF("Parse program .dynamic section at %p\n", p_info->dynamic);
                dynamic_parse(p_info->dynamic, 0, &prog->dyn);
        } else {
                DPRINTF("Program is statically linked\n");
        }
        prog->bias = 0;
        prog->dyn.soname = "[program]";
        prog->rtld = env;
        prog->id = rtld_get_next_id(env);
        prog->exec = true;
        prog->local = false;

        prog->tdata = p_info->tls.tdata;
        prog->tdata_size = p_info->tls.tdata_size;
        prog->tbss_size = p_info->tls.tbss_size;
        prog->tls_align = p_info->tls.tls_align;

        DPRINTF("prog tdata at %p size %zu, tbss size %zu\n",
            prog->tdata, prog->tdata_size, prog->tbss_size);

        /* Initialize list of loaded modules */
        list_initialize(&env->modules);
        list_initialize(&env->imodules);
        list_append(&prog->modules_link, &env->modules);

        /* Pointer to program module. Used as root of the module graph. */
        env->program = prog;

        /*
         * Now we can continue with loading all other modules.
         */

        if (p_info->dynamic) {
                DPRINTF("Load all program dependencies\n");
                errno_t rc = module_load_deps(prog, 0);
                if (rc != EOK) {
                        free(prog);
                        free(env);
                        return rc;
                }
        }

        /* Compute static TLS size */
        modules_process_tls(env);

        /*
         * Now relocate/link all modules together.
         */

        /* Process relocations in all modules */
        DPRINTF("Relocate all modules\n");
        modules_process_relocs(env, prog);

        *rre = env;
        return EOK;
}

/** Create TLS (Thread Local Storage) data structures.
 *
 * @return Pointer to TCB.
 */
tcb_t *rtld_tls_make(rtld_t *rtld)
{
        tcb_t *tcb;
        void **dtv;
        size_t nmods;
        size_t i;

        tcb = tls_alloc_arch(rtld->tls_size, rtld->tls_align);
        if (tcb == NULL)
                return NULL;

        /** Allocate dynamic thread vector */
        nmods = list_count(&rtld->imodules);
        dtv = malloc((nmods + 1) * sizeof(void *));
        if (dtv == NULL) {
                tls_free(tcb);
                return NULL;
        }

        /*
         * We define generation number to be equal to vector length.
         * We start with a vector covering the initially loaded modules.
         */
        DTV_GN(dtv) = nmods;

        /*
         * Copy thread local data from the initialization images of initial
         * modules. Zero out thread-local uninitialized data.
         */

        i = 1;
        list_foreach(rtld->imodules, imodules_link, module_t, m) {
                assert(i++ == m->id);

                dtv[m->id] = (void *) tcb + m->tpoff;

                assert(((uintptr_t) dtv[m->id]) % m->tls_align == 0);

                if (m->tdata)
                        memcpy(dtv[m->id], m->tdata, m->tdata_size);

                memset(dtv[m->id] + m->tdata_size, 0, m->tbss_size);
        }

        tcb->dtv = dtv;
        return tcb;
}

unsigned long rtld_get_next_id(rtld_t *rtld)
{
        return rtld->next_id++;
}

/** Get address of thread-local variable.
 *
 * @param rtld RTLD instance
 * @param tcb TCB of the thread whose instance to return
 * @param mod_id Module ID
 * @param offset Offset within TLS block of the module
 *
 * @return Address of thread-local variable
 */
void *rtld_tls_get_addr(rtld_t *rtld, tcb_t *tcb, unsigned long mod_id,
    unsigned long offset)
{
        module_t *m;
        size_t dtv_len;
        void *tls_block;

        dtv_len = DTV_GN(tcb->dtv);
        if (dtv_len < mod_id) {
                /* Vector is short */

                tcb->dtv = realloc(tcb->dtv, (1 + mod_id) * sizeof(void *));
                /* XXX This can fail if OOM */
                assert(tcb->dtv != NULL);
                /* Zero out new part of vector */
                memset(tcb->dtv + (1 + dtv_len), 0, (mod_id - dtv_len) *
                    sizeof(void *));
        }

        if (tcb->dtv[mod_id] == NULL) {
                /* TLS block is not allocated */

                m = module_by_id(rtld, mod_id);
                assert(m != NULL);
                /* Should not be initial module, those have TLS pre-allocated */
                assert(!link_used(&m->imodules_link));

                tls_block = memalign(m->tls_align, m->tdata_size + m->tbss_size);
                /* XXX This can fail if OOM */
                assert(tls_block != NULL);

                /* Copy tdata */
                memcpy(tls_block, m->tdata, m->tdata_size);
                /* Zero out tbss */
                memset(tls_block + m->tdata_size, 0, m->tbss_size);

                tcb->dtv[mod_id] = tls_block;
        }

        return (uint8_t *)(tcb->dtv[mod_id]) + offset;
}

/** @}
 */