source: mainline/uspace/srv/loader/main.c@ 3e6a98c5

/*
 * 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 loader
 * @brief Loads and runs programs from VFS.
 * @{
 */
/**
 * @file
 * @brief Loads and runs programs from VFS.
 *
 * The program loader is a special init binary. Its image is used
 * to create a new task upon a @c task_spawn syscall. The syscall
 * returns the id of a phone connected to the newly created task.
 *
 * The caller uses this phone to send the pathname and various other
 * information to the loader. This is normally done by the C library
 * and completely hidden from applications.
 */

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <stdbool.h>
#include <fcntl.h>
#include <sys/types.h>
#include <ipc/services.h>
#include <ipc/loader.h>
#include <ns.h>
#include <loader/pcb.h>
#include <entry_point.h>
#include <errno.h>
#include <async.h>
#include <str.h>
#include <as.h>
#include <elf/elf.h>
#include <elf/elf_load.h>
#include <vfs/vfs.h>

#ifdef CONFIG_RTLD
#include <rtld/rtld.h>
#include <rtld/dynamic.h>
#include <rtld/module.h>

static int ldr_load_dyn_linked(elf_info_t *p_info);
#endif

#define DPRINTF(...)

/** Pathname of the file that will be loaded */
static char *pathname = NULL;

/** The Program control block */
static pcb_t pcb;

/** Current working directory */
static char *cwd = NULL;

/** Number of arguments */
static int argc = 0;
/** Argument vector */
static char **argv = NULL;
/** Buffer holding all arguments */
static char *arg_buf = NULL;

/** Number of preset files */
static unsigned int filc = 0;

static elf_info_t prog_info;

/** Used to limit number of connections to one. */
static bool connected = false;

#ifdef CONFIG_RTLD
/** State structure of the dynamic linker. */
runtime_env_t dload_re;
static module_t prog_mod;
#endif

static void ldr_get_taskid(ipc_callid_t rid, ipc_call_t *request)
{
        ipc_callid_t callid;
        task_id_t task_id;
        size_t len;
        
        task_id = task_get_id();
        
        if (!async_data_read_receive(&callid, &len)) {
                async_answer_0(callid, EINVAL);
                async_answer_0(rid, EINVAL);
                return;
        }
        
        if (len > sizeof(task_id))
                len = sizeof(task_id);
        
        async_data_read_finalize(callid, &task_id, len);
        async_answer_0(rid, EOK);
}

/** Receive a call setting the current working directory.
 *
 * @param rid
 * @param request
 */
static void ldr_set_cwd(ipc_callid_t rid, ipc_call_t *request)
{
        char *buf;
        int rc = async_data_write_accept((void **) &buf, true, 0, 0, 0, NULL);
        
        if (rc == EOK) {
                if (cwd != NULL)
                        free(cwd);
                
                cwd = buf;
        }
        
        async_answer_0(rid, rc);
}

/** Receive a call setting pathname of the program to execute.
 *
 * @param rid
 * @param request
 */
static void ldr_set_pathname(ipc_callid_t rid, ipc_call_t *request)
{
        char *buf;
        int rc = async_data_write_accept((void **) &buf, true, 0, 0, 0, NULL);
        
        if (rc == EOK) {
                if (pathname != NULL)
                        free(pathname);
                
                pathname = buf;
        }
        
        async_answer_0(rid, rc);
}

/** Receive a call setting arguments of the program to execute.
 *
 * @param rid
 * @param request
 */
static void ldr_set_args(ipc_callid_t rid, ipc_call_t *request)
{
        char *buf;
        size_t buf_size;
        int rc = async_data_write_accept((void **) &buf, true, 0, 0, 0, &buf_size);
        
        if (rc == EOK) {
                /*
                 * Count number of arguments
                 */
                char *cur = buf;
                int count = 0;
                
                while (cur < buf + buf_size) {
                        size_t arg_size = str_size(cur);
                        cur += arg_size + 1;
                        count++;
                }
                
                /*
                 * Allocate new argv
                 */
                char **_argv = (char **) malloc((count + 1) * sizeof(char *));
                if (_argv == NULL) {
                        free(buf);
                        async_answer_0(rid, ENOMEM);
                        return;
                }
                
                /*
                 * Fill the new argv with argument pointers
                 */
                cur = buf;
                count = 0;
                while (cur < buf + buf_size) {
                        _argv[count] = cur;
                        
                        size_t arg_size = str_size(cur);
                        cur += arg_size + 1;
                        count++;
                }
                _argv[count] = NULL;
                
                /*
                 * Copy temporary data to global variables
                 */
                if (arg_buf != NULL)
                        free(arg_buf);
                
                if (argv != NULL)
                        free(argv);
                
                argc = count;
                arg_buf = buf;
                argv = _argv;
        }
        
        async_answer_0(rid, rc);
}

/** Receive a call setting preset files of the program to execute.
 *
 * @param rid
 * @param request
 */
static void ldr_set_files(ipc_callid_t rid, ipc_call_t *request)
{
        size_t count = IPC_GET_ARG1(*request);

        async_exch_t *vfs_exch = vfs_exchange_begin();

        for (filc = 0; filc < count; filc++) {
                ipc_callid_t callid;
                int fd;

                if (!async_state_change_receive(&callid, NULL, NULL, NULL)) {
                        async_answer_0(callid, EINVAL);
                        break;
                }
                async_state_change_finalize(callid, vfs_exch);
                fd = fd_wait();
                assert(fd == (int) filc);
        }

        vfs_exchange_end(vfs_exch);

        async_answer_0(rid, EOK);
}

/** Load the previously selected program.
 *
 * @param rid
 * @param request
 * @return 0 on success, !0 on error.
 */
static int ldr_load(ipc_callid_t rid, ipc_call_t *request)
{
        int rc;
        
        rc = elf_load_file(pathname, 0, 0, &prog_info);
        if (rc != EE_OK) {
                DPRINTF("Failed to load executable '%s'.\n", pathname);
                async_answer_0(rid, EINVAL);
                return 1;
        }
        
        elf_create_pcb(&prog_info, &pcb);
        
        pcb.cwd = cwd;
        
        pcb.argc = argc;
        pcb.argv = argv;
        
        pcb.filc = filc;
        
        if (prog_info.interp == NULL) {
                /* Statically linked program */
                async_answer_0(rid, EOK);
                return 0;
        }
        
        DPRINTF("Binary is dynamically linked.\n");
#ifdef CONFIG_RTLD
        DPRINTF(" - pcb address: %p\n", &pcb);
        DPRINTF( "- prog dynamic: %p\n", prog_info.dynamic);

        rc = ldr_load_dyn_linked(&prog_info);
#else
        rc = ENOTSUP;
#endif
        async_answer_0(rid, rc);
        return 0;
}

#ifdef CONFIG_RTLD

static int ldr_load_dyn_linked(elf_info_t *p_info)
{
        runtime_env = &dload_re;

        DPRINTF("Load dynamically linked program.\n");

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

        DPRINTF("Parse program .dynamic section at %p\n", p_info->dynamic);
        dynamic_parse(p_info->dynamic, 0, &prog_mod.dyn);
        prog_mod.bias = 0;
        prog_mod.dyn.soname = "[program]";

        /* Initialize list of loaded modules */
        list_initialize(&runtime_env->modules);
        list_append(&prog_mod.modules_link, &runtime_env->modules);

        /* Pointer to program module. Used as root of the module graph. */
        runtime_env->program = &prog_mod;

        /* Work around non-existent memory space allocation. */
        runtime_env->next_bias = 0x1000000;

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

        DPRINTF("Load all program dependencies\n");
        module_load_deps(&prog_mod);

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

        /* Process relocations in all modules */
        DPRINTF("Relocate all modules\n");
        modules_process_relocs(&prog_mod);

        /* Pass runtime evironment pointer through PCB. */
        pcb.rtld_runtime = (void *) runtime_env;

        return 0;
}
#endif

/** Run the previously loaded program.
 *
 * @param rid
 * @param request
 * @return 0 on success, !0 on error.
 */
static void ldr_run(ipc_callid_t rid, ipc_call_t *request)
{
        const char *cp;
        
        DPRINTF("Set task name\n");

        /* Set the task name. */
        cp = str_rchr(pathname, '/');
        cp = (cp == NULL) ? pathname : (cp + 1);
        task_set_name(cp);
        
        /* Run program */
        DPRINTF("Reply OK\n");
        async_answer_0(rid, EOK);
        DPRINTF("Jump to entry point at %p\n", pcb.entry);
        entry_point_jmp(prog_info.entry, &pcb);
        
        /* Not reached */
}

/** Handle loader connection.
 *
 * Receive and carry out commands (of which the last one should be
 * to execute the loaded program).
 */
static void ldr_connection(ipc_callid_t iid, ipc_call_t *icall, void *arg)
{
        /* Already have a connection? */
        if (connected) {
                async_answer_0(iid, ELIMIT);
                return;
        }
        
        connected = true;
        
        /* Accept the connection */
        async_answer_0(iid, EOK);
        
        /* Ignore parameters, the connection is already open */
        (void) icall;
        
        while (true) {
                int retval;
                ipc_call_t call;
                ipc_callid_t callid = async_get_call(&call);
                
                if (!IPC_GET_IMETHOD(call))
                        exit(0);
                
                switch (IPC_GET_IMETHOD(call)) {
                case LOADER_GET_TASKID:
                        ldr_get_taskid(callid, &call);
                        continue;
                case LOADER_SET_CWD:
                        ldr_set_cwd(callid, &call);
                        continue;
                case LOADER_SET_PATHNAME:
                        ldr_set_pathname(callid, &call);
                        continue;
                case LOADER_SET_ARGS:
                        ldr_set_args(callid, &call);
                        continue;
                case LOADER_SET_FILES:
                        ldr_set_files(callid, &call);
                        continue;
                case LOADER_LOAD:
                        ldr_load(callid, &call);
                        continue;
                case LOADER_RUN:
                        ldr_run(callid, &call);
                        /* Not reached */
                default:
                        retval = EINVAL;
                        break;
                }
                
                async_answer_0(callid, retval);
        }
}

/** Program loader main function.
 */
int main(int argc, char *argv[])
{
        /* Set a handler of incomming connections. */
        async_set_client_connection(ldr_connection);
        
        /* Introduce this task to the NS (give it our task ID). */
        task_id_t id = task_get_id();
        int rc = ns_intro(id);
        if (rc != EOK)
                return rc;
        
        /* Register at naming service. */
        rc = service_register(SERVICE_LOAD);
        if (rc != EOK)
                return rc;
        
        async_manager();
        
        /* Never reached */
        return 0;
}

/** @}
 */