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/*
 * Copyright (c) 2006 Jakub Jermar
 * 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 libc
 * @{
 */
/** @file
 */ 

#include <task.h>
#include <ipc/ipc.h>
#include <ipc/loader.h>
#include <libc.h>
#include <string.h>
#include <stdlib.h>
#include <async.h>
#include <errno.h>
#include <vfs/vfs.h>

task_id_t task_get_id(void)
{
    task_id_t task_id;

    (void) __SYSCALL1(SYS_TASK_GET_ID, (sysarg_t) &task_id);

    return task_id;
}

static int task_spawn_loader(void)
{
    int phone_id, rc;

    rc = __SYSCALL1(SYS_PROGRAM_SPAWN_LOADER, (sysarg_t) &phone_id);
    if (rc != 0)
        return rc;

    return phone_id;
}

static int loader_set_args(int phone_id, const char *argv[])
{
    aid_t req;
    ipc_call_t answer;
    ipcarg_t rc;

    const char **ap;
    char *dp;
    char *arg_buf;
    size_t buffer_size;
    size_t len;

    /* 
     * Serialize the arguments into a single array. First
     * compute size of the buffer needed.
     */
    ap = argv;
    buffer_size = 0;
    while (*ap != NULL) {
        buffer_size += strlen(*ap) + 1;
        ++ap;
    }

    arg_buf = malloc(buffer_size);
    if (arg_buf == NULL) return ENOMEM;

    /* Now fill the buffer with null-terminated argument strings */
    ap = argv;
    dp = arg_buf;
    while (*ap != NULL) {
        strcpy(dp, *ap);
        dp += strlen(*ap) + 1;

        ++ap;
    }

    /* Send serialized arguments to the loader */

    req = async_send_0(phone_id, LOADER_SET_ARGS, &answer);
    rc = ipc_data_write_start(phone_id, (void *)arg_buf, buffer_size);
    if (rc != EOK) {
        async_wait_for(req, NULL);
        return rc;
    }

    async_wait_for(req, &rc);
    if (rc != EOK) return rc;

    /* Free temporary buffer */
    free(arg_buf);

    return EOK;
}

/** Create a new task by running an executable from VFS.
 *
 * @param path  pathname of the binary to execute
 * @param argv  command-line arguments
 * @return  ID of the newly created task or zero on error.
 */
task_id_t task_spawn(const char *path, const char *argv[])
{
    int phone_id;
    ipc_call_t answer;
    aid_t req;
    int rc;
    ipcarg_t retval;

    char *pa;
    size_t pa_len;
    task_id_t task_id;

    pa = absolutize(path, &pa_len);
    if (!pa)
        return 0;

    /* Spawn a program loader */    
    phone_id = task_spawn_loader();
    if (phone_id < 0)
        return 0;

    /*
     * Say hello so that the loader knows the incoming connection's
     * phone hash.
     */
    rc = async_req_0_0(phone_id, LOADER_HELLO);
    if (rc != EOK)
        return 0;

    /* Get task ID. */
    req = async_send_0(phone_id, LOADER_GET_TASKID, &answer);
    rc = ipc_data_read_start(phone_id, &task_id, sizeof(task_id));
    if (rc != EOK) {
        async_wait_for(req, NULL);
        goto error;
    }

    async_wait_for(req, &retval);
    if (retval != EOK)
        goto error;

    /* Send program pathname */
    req = async_send_0(phone_id, LOADER_SET_PATHNAME, &answer);
    rc = ipc_data_write_start(phone_id, (void *)pa, pa_len);
    if (rc != EOK) {
        async_wait_for(req, NULL);
        return 1;
    }

    async_wait_for(req, &retval);
    if (retval != EOK)
        goto error;

    /* Send arguments */
    rc = loader_set_args(phone_id, argv);
    if (rc != EOK)
        goto error;

    /* Request loader to start the program */   
    rc = async_req_0_0(phone_id, LOADER_RUN);
    if (rc != EOK)
        goto error;

    /* Success */
    ipc_hangup(phone_id);
    return task_id;

    /* Error exit */
error:
    ipc_hangup(phone_id);
    return 0;
}

/** @}
 */