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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 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;

}

/** @}

 */