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/*

 * Copyright (c) 2001-2004 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 genericproc

 * @{

 */

/**

 * @file

 * @brief   Running userspace programs.

 */

#include <main/uinit.h>

#include <proc/thread.h>

#include <proc/task.h>

#include <proc/uarg.h>

#include <mm/as.h>

#include <mm/slab.h>

#include <arch.h>

#include <adt/list.h>

#include <ipc/ipc.h>

#include <ipc/ipcrsc.h>

#include <security/cap.h>

#include <lib/elf.h>

#include <errno.h>

#include <syscall/copy.h>

#include <proc/program.h>

#ifndef LOADED_PROG_STACK_PAGES_NO

#define LOADED_PROG_STACK_PAGES_NO 1

#endif

/**

 * Points to the binary image used as the program loader. All non-initial

 * tasks are created from this executable image.

 */

void *program_loader = NULL;

/** Create a program using an existing address space.

 *

 * @param as        Address space containing a binary program image.

 * @param entry_addr    Program entry-point address in program address space.

 * @param name      Name to set for the program's task.

 * @param p     Buffer for storing program information.

 */

void program_create(as_t *as, uintptr_t entry_addr, char *name, program_t *p)

{

    as_area_t *a;

    uspace_arg_t *kernel_uarg;

    kernel_uarg = (uspace_arg_t *) malloc(sizeof(uspace_arg_t), 0);

    kernel_uarg->uspace_entry = (void *) entry_addr;

    kernel_uarg->uspace_stack = (void *) USTACK_ADDRESS;

    kernel_uarg->uspace_thread_function = NULL;

    kernel_uarg->uspace_thread_arg = NULL;

    kernel_uarg->uspace_uarg = NULL;

    p->task = task_create(as, name);

    ASSERT(p->task);

    /*

     * Create the data as_area.

     */

    a = as_area_create(as, AS_AREA_READ | AS_AREA_WRITE | AS_AREA_CACHEABLE,

        LOADED_PROG_STACK_PAGES_NO * PAGE_SIZE, USTACK_ADDRESS,

        AS_AREA_ATTR_NONE, &anon_backend, NULL);

    /*

     * Create the main thread.

     */

    p->main_thread = thread_create(uinit, kernel_uarg, p->task,

        THREAD_FLAG_USPACE, "uinit", false);

    ASSERT(p->main_thread);

}

/** Parse an executable image in the kernel memory.

 *

 * If the image belongs to a program loader, it is registered as such,

 * (and *task is set to NULL). Otherwise a task is created from the

 * executable image. The task is returned in *task.

 *

 * @param image_addr    Address of an executable program image.

 * @param name      Name to set for the program's task.

 * @param p     Buffer for storing program info. If image_addr

 *          points to a loader image, p->task will be set to

 *          NULL and EOK will be returned.

 *

 * @return EOK on success or negative error code.

 */

int program_create_from_image(void *image_addr, char *name, program_t *p)

{

    as_t *as;

    unsigned int rc;

    as = as_create(0);

    ASSERT(as);

    rc = elf_load((elf_header_t *) image_addr, as, 0);

    if (rc != EE_OK) {

        as_destroy(as);

        p->task = NULL;

        p->main_thread = NULL;

        if (rc != EE_LOADER)

            return ENOTSUP;

        /* Register image as the program loader */

        ASSERT(program_loader == NULL);

        program_loader = image_addr;

        return EOK;

    }

    program_create(as, ((elf_header_t *) image_addr)->e_entry, name, p);

    return EOK;

}

/** Create a task from the program loader image.

 *

 * @param p Buffer for storing program info.

 * @param name  Name to set for the program's task.

 *

 * @return EOK on success or negative error code.

 */

int program_create_loader(program_t *p, char *name)

{

    as_t *as;

    unsigned int rc;

    void *loader;

    as = as_create(0);

    ASSERT(as);

    loader = program_loader;

    if (!loader) return ENOENT;

    rc = elf_load((elf_header_t *) program_loader, as, ELD_F_LOADER);

    if (rc != EE_OK) {

        as_destroy(as);

        return ENOENT;

    }

    program_create(as, ((elf_header_t *) program_loader)->e_entry,

        name, p);

    return EOK;

}

/** Make program ready.

 *

 * Switch program's main thread to the ready state.

 *

 * @param p Program to make ready.

 */

void program_ready(program_t *p)

{

    thread_ready(p->main_thread);

}

/** Syscall for creating a new loader instance from userspace.

 *

 * Creates a new task from the program loader image, connects a phone

 * to it and stores the phone id into the provided buffer.

 *

 * @param uspace_phone_id   Userspace address where to store the phone id.

 * @param name          Name to set on the new task (typically the same

 *              as the command used to execute it).

 *

 * @return 0 on success or an error code from @ref errno.h.

 */

unative_t sys_program_spawn_loader(int *uspace_phone_id, char *uspace_name,

    size_t name_len)

{

    program_t p;

    int fake_id;

    int rc;

    int phone_id;

    char namebuf[TASK_NAME_BUFLEN];

    fake_id = 0;

    /* Before we even try creating the task, see if we can write the id */

    rc = (unative_t) copy_to_uspace(uspace_phone_id, &fake_id,

        sizeof(fake_id));

    if (rc != 0)

        return rc;

    /* Cap length of name and copy it from userspace. */

    if (name_len > THREAD_NAME_BUFLEN - 1)

        name_len = THREAD_NAME_BUFLEN - 1;

    rc = copy_from_uspace(namebuf, uspace_name, name_len);

    if (rc != 0)

        return (unative_t) rc;

    namebuf[name_len] = '\0';

    /* Allocate the phone for communicating with the new task. */

    phone_id = phone_alloc();

    if (phone_id < 0)

        return ELIMIT;

    /* Spawn the new task. */

    rc = program_create_loader(&p, namebuf);

    if (rc != 0)

        return rc;

    phone_connect(phone_id, &p.task->answerbox);

    /* No need to aquire lock before task_ready() */

    rc = (unative_t) copy_to_uspace(uspace_phone_id, &phone_id,

        sizeof(phone_id));

    if (rc != 0) {

        /* Ooops */

        ipc_phone_hangup(&TASK->phones[phone_id]);

        task_kill(p.task->taskid);

        return rc;

    }

    // FIXME: control the capabilities

    cap_set(p.task, cap_get(TASK));

    program_ready(&p);

    return EOK;

}

/** @}

 */