source: mainline/kernel/generic/src/proc/program.c@ d3109ff

/*
 * 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 kernel_generic_proc
 * @{
 */

/**
 * @file
 * @brief Running userspace programs.
 */

#include <main/uinit.h>
#include <proc/thread.h>
#include <proc/task.h>
#include <mm/as.h>
#include <stdlib.h>
#include <arch.h>
#include <adt/list.h>
#include <ipc/ipc.h>
#include <ipc/ipcrsc.h>
#include <security/perm.h>
#include <lib/elf_load.h>
#include <str.h>
#include <str_error.h>
#include <log.h>
#include <syscall/copy.h>
#include <proc/program.h>
#include <userspace.h>

/**
 * 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 prg        Buffer for storing program information.
 *
 * @return EOK on success or an error code.
 *
 */
errno_t program_create(as_t *as, uspace_addr_t entry_addr, char *name, program_t *prg)
{
        uinit_arg_t *kernel_uarg = malloc(sizeof(uinit_arg_t));
        if (!kernel_uarg)
                return ENOMEM;

        prg->loader_status = EOK;
        prg->task = task_create(as, name);
        if (!prg->task) {
                free(kernel_uarg);
                return ELIMIT;
        }

        /*
         * Create the stack address space area.
         */
        uintptr_t virt = (uintptr_t) AS_AREA_ANY;
        uintptr_t bound = USER_ADDRESS_SPACE_END - (STACK_SIZE_USER - 1);

        /* Adjust bound to create space for the desired guard page. */
        bound -= PAGE_SIZE;

        as_area_t *area = as_area_create(as,
            AS_AREA_READ | AS_AREA_WRITE | AS_AREA_CACHEABLE | AS_AREA_GUARD |
            AS_AREA_LATE_RESERVE, STACK_SIZE_USER, AS_AREA_ATTR_NONE,
            &anon_backend, NULL, &virt, bound);
        if (!area) {
                free(kernel_uarg);
                task_release(prg->task);
                prg->task = NULL;
                return ENOMEM;
        }

        kernel_uarg->pc = entry_addr;
        kernel_uarg->sp = arch_get_initial_sp(virt, STACK_SIZE_USER);

        /*
         * Create the main thread.
         */
        prg->main_thread = thread_create(uinit, kernel_uarg, prg->task,
            THREAD_FLAG_USPACE, "uinit");
        if (!prg->main_thread) {
                free(kernel_uarg);
                as_area_destroy(as, virt);
                task_release(prg->task);
                prg->task = NULL;
                return ELIMIT;
        }

        return EOK;
}

/** 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[in]  image_addr Address of an executable program image.
 * @param[in]  name       Name to set for the program's task.
 * @param[out] prg        Buffer for storing program info.
 *                        If image_addr points to a loader image,
 *                        prg->task will be set to NULL and EOK
 *                        will be returned.
 *
 * @return EOK on success or an error code.
 *
 */
errno_t program_create_from_image(void *image_addr, size_t image_size, char *name, program_t *prg)
{
        as_t *as = as_create(0);
        if (!as)
                return ENOMEM;

        prg->loader_status = elf_load((elf_header_t *) image_addr, as);
        if (prg->loader_status != EOK) {
                as_release(as);
                prg->task = NULL;
                prg->main_thread = NULL;
                return ENOTSUP;
        }

        errno_t rc = program_create(as, ((elf_header_t *) image_addr)->e_entry,
            name, prg);

        if (rc == EOK) {
                prg->task->debug_sections = calloc(1, sizeof(debug_sections_t));
                if (prg->task->debug_sections != NULL)
                        *prg->task->debug_sections = get_debug_sections(image_addr, image_size);
        }

        return rc;
}

/** Create a task from the program loader image.
 *
 * @param prg  Buffer for storing program info.
 * @param name Name to set for the program's task.
 *
 * @return EOK on success or an error code.
 *
 */
errno_t program_create_loader(program_t *prg, char *name)
{
        as_t *as = as_create(0);
        if (!as)
                return ENOMEM;

        void *loader = program_loader;
        if (!loader) {
                as_release(as);
                log(LF_OTHER, LVL_ERROR,
                    "Cannot spawn loader as none was registered");
                return ENOENT;
        }

        prg->loader_status = elf_load((elf_header_t *) program_loader, as);
        if (prg->loader_status != EOK) {
                as_release(as);
                log(LF_OTHER, LVL_ERROR, "Cannot spawn loader (%s)",
                    str_error(prg->loader_status));
                return prg->loader_status;
        }

        return program_create(as, ((elf_header_t *) program_loader)->e_entry,
            name, prg);
}

/** Make program ready.
 *
 * Switch program's main thread to the ready state.
 *
 * @param prg Program to make ready.
 *
 */
void program_ready(program_t *prg)
{
        thread_start(prg->main_thread);
        thread_detach(prg->main_thread);
        prg->main_thread = NULL;
}

/** Syscall for creating a new loader instance from userspace.
 *
 * Creates a new task from the program loader image and sets
 * the task name.
 *
 * @param uspace_name Name to set on the new task (typically the same
 *                    as the command used to execute it).
 * @param name_len    Length of the name.
 *
 * @return EOK on success or an error code from @ref errno.h.
 *
 */
sys_errno_t sys_program_spawn_loader(uspace_ptr_char uspace_name, size_t name_len)
{
        /* Cap length of name and copy it from userspace. */
        if (name_len > TASK_NAME_BUFLEN - 1)
                name_len = TASK_NAME_BUFLEN - 1;

        char namebuf[TASK_NAME_BUFLEN];
        errno_t rc = copy_from_uspace(namebuf, uspace_name, name_len);
        if (rc != EOK)
                return (sys_errno_t) rc;

        namebuf[name_len] = 0;

        /* Spawn the new task. */
        program_t prg;
        rc = program_create_loader(&prg, namebuf);
        if (rc != EOK)
                return rc;

        // FIXME: control the permissions
        perm_set(prg.task, perm_get(TASK));
        program_ready(&prg);

        task_release(prg.task);

        return EOK;
}

/** @}
 */