source: mainline/uspace/srv/loader/main.c@ 561db3f

/*
 * 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 <bool.h>
#include <fcntl.h>
#include <sys/types.h>
#include <ipc/ipc.h>
#include <ipc/services.h>
#include <ipc/loader.h>
#include <loader/pcb.h>
#include <errno.h>
#include <async.h>
#include <as.h>

#include <elf.h>
#include <elf_load.h>

#define DPRINTF(...)

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

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

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

static elf_info_t prog_info;
static elf_info_t interp_info;

static bool is_dyn_linked;

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

static void loader_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 (!ipc_data_read_receive(&callid, &len)) {
                ipc_answer_0(callid, EINVAL);
                ipc_answer_0(rid, EINVAL);
                return;
        }

        if (len > sizeof(task_id)) len = sizeof(task_id);

        ipc_data_read_finalize(callid, &task_id, len);
        ipc_answer_0(rid, EOK);
}


/** Receive a call setting pathname of the program to execute.
 *
 * @param rid
 * @param request
 */
static void loader_set_pathname(ipc_callid_t rid, ipc_call_t *request)
{
        ipc_callid_t callid;
        size_t len;
        char *name_buf;

        if (!ipc_data_write_receive(&callid, &len)) {
                ipc_answer_0(callid, EINVAL);
                ipc_answer_0(rid, EINVAL);
                return;
        }

        name_buf = malloc(len + 1);
        if (!name_buf) {
                ipc_answer_0(callid, ENOMEM);
                ipc_answer_0(rid, ENOMEM);
                return;
        }

        ipc_data_write_finalize(callid, name_buf, len);
        ipc_answer_0(rid, EOK);

        if (pathname != NULL) {
                free(pathname);
                pathname = NULL;
        }

        name_buf[len] = '\0';
        pathname = name_buf;
}

/** Receive a call setting arguments of the program to execute.
 *
 * @param rid
 * @param request
 */
static void loader_set_args(ipc_callid_t rid, ipc_call_t *request)
{
        ipc_callid_t callid;
        size_t buf_len, arg_len;
        char *p;
        int n;

        if (!ipc_data_write_receive(&callid, &buf_len)) {
                ipc_answer_0(callid, EINVAL);
                ipc_answer_0(rid, EINVAL);
                return;
        }

        if (arg_buf != NULL) {
                free(arg_buf);
                arg_buf = NULL;
        }

        if (argv != NULL) {
                free(argv);
                argv = NULL;
        }

        arg_buf = malloc(buf_len + 1);
        if (!arg_buf) {
                ipc_answer_0(callid, ENOMEM);
                ipc_answer_0(rid, ENOMEM);
                return;
        }

        ipc_data_write_finalize(callid, arg_buf, buf_len);
        ipc_answer_0(rid, EOK);

        arg_buf[buf_len] = '\0';

        /*
         * Count number of arguments
         */
        p = arg_buf;
        n = 0;
        while (p < arg_buf + buf_len) {
                arg_len = strlen(p);
                p = p + arg_len + 1;
                ++n;
        }

        /* Allocate argv */
        argv = malloc((n + 1) * sizeof(char *));

        if (argv == NULL) {
                free(arg_buf);
                ipc_answer_0(callid, ENOMEM);
                ipc_answer_0(rid, ENOMEM);
                return;
        }

        /*
         * Fill argv with argument pointers
         */
        p = arg_buf;
        n = 0;
        while (p < arg_buf + buf_len) {
                argv[n] = p;

                arg_len = strlen(p);
                p = p + arg_len + 1;
                ++n;
        }

        argc = n;
        argv[n] = NULL;
}

/** Load the previously selected program.
 *
 * @param rid
 * @param request
 * @return 0 on success, !0 on error.
 */
static int loader_load(ipc_callid_t rid, ipc_call_t *request)
{
        int rc;

        rc = elf_load_file(pathname, 0, &prog_info);
        if (rc < 0) {
                DPRINTF("Failed to load executable '%s'.\n", pathname);
                ipc_answer_0(rid, EINVAL);
                return 1;
        }

        elf_create_pcb(&prog_info, &pcb);

        pcb.argc = argc;
        pcb.argv = argv;

        if (prog_info.interp == NULL) {
                /* Statically linked program */
                is_dyn_linked = false;
                ipc_answer_0(rid, EOK);
                return 0;
        }

        rc = elf_load_file(prog_info.interp, 0, &interp_info);
        if (rc < 0) {
                DPRINTF("Failed to load interpreter '%s.'\n",
                    prog_info.interp);
                ipc_answer_0(rid, EINVAL);
                return 1;
        }

        is_dyn_linked = true;
        ipc_answer_0(rid, EOK);

        return 0;
}


/** Run the previously loaded program.
 *
 * @param rid
 * @param request
 * @return 0 on success, !0 on error.
 */
static void loader_run(ipc_callid_t rid, ipc_call_t *request)
{
        const char *cp;

        /* Set the task name. */
        cp = strrchr(pathname, '/');
        cp = (cp == NULL) ? pathname : (cp + 1);
        task_set_name(cp);

        if (is_dyn_linked == true) {
                /* Dynamically linked program */
                DPRINTF("Run ELF interpreter.\n");
                DPRINTF("Entry point: 0x%lx\n", interp_info.entry);
                close_console();

                ipc_answer_0(rid, EOK);
                elf_run(&interp_info, &pcb);

        } else {
                /* Statically linked program */
                close_console();
                ipc_answer_0(rid, EOK);
                elf_run(&prog_info, &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 loader_connection(ipc_callid_t iid, ipc_call_t *icall)
{
        ipc_callid_t callid;
        ipc_call_t call;
        int retval;

        /* Already have a connection? */
        if (connected) {
                ipc_answer_0(iid, ELIMIT);
                return;
        }

        connected = true;
        
        /* Accept the connection */
        ipc_answer_0(iid, EOK);

        /* Ignore parameters, the connection is already open */
        (void)iid; (void)icall;

        while (1) {
                callid = async_get_call(&call);

                switch (IPC_GET_METHOD(call)) {
                case IPC_M_PHONE_HUNGUP:
                        exit(0);
                case LOADER_GET_TASKID:
                        loader_get_taskid(callid, &call);
                        continue;
                case LOADER_SET_PATHNAME:
                        loader_set_pathname(callid, &call);
                        continue;
                case LOADER_SET_ARGS:
                        loader_set_args(callid, &call);
                        continue;
                case LOADER_LOAD:
                        loader_load(callid, &call);
                        continue;
                case LOADER_RUN:
                        loader_run(callid, &call);
                        /* Not reached */
                default:
                        retval = ENOENT;
                        break;
                }
                if ((callid & IPC_CALLID_NOTIFICATION) == 0 &&
                    IPC_GET_METHOD(call) != IPC_M_PHONE_HUNGUP) {
                        DPRINTF("Responding EINVAL to method %d.\n",
                            IPC_GET_METHOD(call));
                        ipc_answer_0(callid, EINVAL);
                }
        }
}

/** Program loader main function.
 */
int main(int argc, char *argv[])
{
        ipcarg_t phonead;

        connected = false;
        
        /* Set a handler of incomming connections. */
        async_set_client_connection(loader_connection);

        /* Register at naming service. */
        if (ipc_connect_to_me(PHONE_NS, SERVICE_LOAD, 0, 0, &phonead) != 0) 
                return -1;
        
        async_manager();

        /* Never reached */
        return 0;
}

/** @}
 */