source: mainline/uspace/srv/loader/main.c@ 3bacee1

/*
 * 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 <stdbool.h>
#include <stddef.h>
#include <ipc/services.h>
#include <ipc/loader.h>
#include <ns.h>
#include <loader/pcb.h>
#include <entry_point.h>
#include <errno.h>
#include <async.h>
#include <str.h>
#include <as.h>
#include <elf/elf.h>
#include <elf/elf_load.h>
#include <vfs/vfs.h>
#include <vfs/inbox.h>

#define DPRINTF(...)

/** File that will be loaded */
static char *progname = NULL;
static int program_fd = -1;

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

/** Current working directory */
static char *cwd = NULL;

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

/** Inbox entries. */
static struct pcb_inbox_entry inbox[INBOX_MAX_ENTRIES];
static int inbox_entries = 0;

static elf_info_t prog_info;

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

static void ldr_get_taskid(cap_call_handle_t req_handle, ipc_call_t *request)
{
        cap_call_handle_t chandle;
        task_id_t task_id;
        size_t len;

        task_id = task_get_id();

        if (!async_data_read_receive(&chandle, &len)) {
                async_answer_0(chandle, EINVAL);
                async_answer_0(req_handle, EINVAL);
                return;
        }

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

        async_data_read_finalize(chandle, &task_id, len);
        async_answer_0(req_handle, EOK);
}

/** Receive a call setting the current working directory.
 *
 * @param req_handle
 * @param request
 */
static void ldr_set_cwd(cap_call_handle_t req_handle, ipc_call_t *request)
{
        char *buf;
        errno_t rc = async_data_write_accept((void **) &buf, true, 0, 0, 0, NULL);

        if (rc == EOK) {
                if (cwd != NULL)
                        free(cwd);

                cwd = buf;
        }

        async_answer_0(req_handle, rc);
}

/** Receive a call setting the program to execute.
 *
 * @param req_handle
 * @param request
 */
static void ldr_set_program(cap_call_handle_t req_handle, ipc_call_t *request)
{
        cap_call_handle_t write_chandle;
        size_t namesize;
        if (!async_data_write_receive(&write_chandle, &namesize)) {
                async_answer_0(req_handle, EINVAL);
                return;
        }

        char *name = malloc(namesize);
        errno_t rc = async_data_write_finalize(write_chandle, name, namesize);
        if (rc != EOK) {
                async_answer_0(req_handle, EINVAL);
                return;
        }

        int file;
        rc = vfs_receive_handle(true, &file);
        if (rc != EOK) {
                async_answer_0(req_handle, EINVAL);
                return;
        }

        progname = name;
        program_fd = file;
        async_answer_0(req_handle, EOK);
}

/** Receive a call setting arguments of the program to execute.
 *
 * @param req_handle
 * @param request
 */
static void ldr_set_args(cap_call_handle_t req_handle, ipc_call_t *request)
{
        char *buf;
        size_t buf_size;
        errno_t rc = async_data_write_accept((void **) &buf, true, 0, 0, 0, &buf_size);

        if (rc == EOK) {
                /*
                 * Count number of arguments
                 */
                char *cur = buf;
                int count = 0;

                while (cur < buf + buf_size) {
                        size_t arg_size = str_size(cur);
                        cur += arg_size + 1;
                        count++;
                }

                /*
                 * Allocate new argv
                 */
                char **_argv = (char **) malloc((count + 1) * sizeof(char *));
                if (_argv == NULL) {
                        free(buf);
                        async_answer_0(req_handle, ENOMEM);
                        return;
                }

                /*
                 * Fill the new argv with argument pointers
                 */
                cur = buf;
                count = 0;
                while (cur < buf + buf_size) {
                        _argv[count] = cur;

                        size_t arg_size = str_size(cur);
                        cur += arg_size + 1;
                        count++;
                }
                _argv[count] = NULL;

                /*
                 * Copy temporary data to global variables
                 */
                if (arg_buf != NULL)
                        free(arg_buf);

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

                argc = count;
                arg_buf = buf;
                argv = _argv;
        }

        async_answer_0(req_handle, rc);
}

/** Receive a call setting inbox files of the program to execute.
 *
 * @param req_handle
 * @param request
 */
static void ldr_add_inbox(cap_call_handle_t req_handle, ipc_call_t *request)
{
        if (inbox_entries == INBOX_MAX_ENTRIES) {
                async_answer_0(req_handle, ERANGE);
                return;
        }

        cap_call_handle_t write_chandle;
        size_t namesize;
        if (!async_data_write_receive(&write_chandle, &namesize)) {
                async_answer_0(req_handle, EINVAL);
                return;
        }

        char *name = malloc(namesize);
        errno_t rc = async_data_write_finalize(write_chandle, name, namesize);
        if (rc != EOK) {
                async_answer_0(req_handle, EINVAL);
                return;
        }

        int file;
        rc = vfs_receive_handle(true, &file);
        if (rc != EOK) {
                async_answer_0(req_handle, EINVAL);
                return;
        }

        /*
         * We need to set the root early for dynamically linked binaries so
         * that the loader can use it too.
         */
        if (str_cmp(name, "root") == 0)
                vfs_root_set(file);

        inbox[inbox_entries].name = name;
        inbox[inbox_entries].file = file;
        inbox_entries++;
        async_answer_0(req_handle, EOK);
}

/** Load the previously selected program.
 *
 * @param req_handle
 * @param request
 * @return 0 on success, !0 on error.
 */
static int ldr_load(cap_call_handle_t req_handle, ipc_call_t *request)
{
        int rc = elf_load(program_fd, &prog_info);
        if (rc != EE_OK) {
                DPRINTF("Failed to load executable for '%s'.\n", progname);
                async_answer_0(req_handle, EINVAL);
                return 1;
        }

        elf_set_pcb(&prog_info, &pcb);

        pcb.cwd = cwd;

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

        pcb.inbox = inbox;
        pcb.inbox_entries = inbox_entries;

        async_answer_0(req_handle, EOK);
        return 0;
}

/** Run the previously loaded program.
 *
 * @param req_handle
 * @param request
 * @return 0 on success, !0 on error.
 */
static __attribute__((noreturn)) void ldr_run(cap_call_handle_t req_handle,
    ipc_call_t *request)
{
        DPRINTF("Set task name\n");

        /* Set the task name. */
        task_set_name(progname);

        /* Run program */
        DPRINTF("Reply OK\n");
        async_answer_0(req_handle, EOK);
        DPRINTF("Jump to entry point at %p\n", pcb.entry);
        entry_point_jmp(prog_info.finfo.entry, &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 ldr_connection(cap_call_handle_t icall_handle, ipc_call_t *icall,
    void *arg)
{
        /* Already have a connection? */
        if (connected) {
                async_answer_0(icall_handle, ELIMIT);
                return;
        }

        connected = true;

        /* Accept the connection */
        async_answer_0(icall_handle, EOK);

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

        while (true) {
                errno_t retval;
                ipc_call_t call;
                cap_call_handle_t chandle = async_get_call(&call);

                if (!IPC_GET_IMETHOD(call))
                        exit(0);

                switch (IPC_GET_IMETHOD(call)) {
                case LOADER_GET_TASKID:
                        ldr_get_taskid(chandle, &call);
                        continue;
                case LOADER_SET_CWD:
                        ldr_set_cwd(chandle, &call);
                        continue;
                case LOADER_SET_PROGRAM:
                        ldr_set_program(chandle, &call);
                        continue;
                case LOADER_SET_ARGS:
                        ldr_set_args(chandle, &call);
                        continue;
                case LOADER_ADD_INBOX:
                        ldr_add_inbox(chandle, &call);
                        continue;
                case LOADER_LOAD:
                        ldr_load(chandle, &call);
                        continue;
                case LOADER_RUN:
                        ldr_run(chandle, &call);
                        /* Not reached */
                default:
                        retval = EINVAL;
                        break;
                }

                async_answer_0(chandle, retval);
        }
}

/** Program loader main function.
 */
int main(int argc, char *argv[])
{
        async_set_fallback_port_handler(ldr_connection, NULL);

        /* Introduce this task to the NS (give it our task ID). */
        task_id_t id = task_get_id();
        errno_t rc = ns_intro(id);
        if (rc != EOK)
                return rc;

        /* Create port */
        port_id_t port;
        rc = async_create_port(INTERFACE_LOADER, ldr_connection, NULL, &port);
        if (rc != EOK)
                return rc;

        /* Register at naming service. */
        rc = service_register(SERVICE_LOADER);
        if (rc != EOK)
                return rc;

        async_manager();

        /* Never reached */
        return 0;
}

/** @}
 */