source: mainline/uspace/srv/loader/main.c@ fe86d9d

/*
 * 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
 * @{
 */
/**
 * @file
 *
 * The program loader is a special init binary. Its image is used
 * to create a new task upon a @c task_spawn syscall. It has a phone connected
 * to the caller of te syscall. The formal caller (taskman) performs a
 * handshake with loader so that apparent caller can communicate with the
 * loader.
 *
 * The apparent caller uses his 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 <as.h>
#include <async.h>
#include <elf/elf.h>
#include <elf/elf_load.h>
#include <entry_point.h>
#include <errno.h>
#include <fcntl.h>
#include <fibril_synch.h>
#include <ipc/loader.h>
#include <loader/pcb.h>
#include <str.h>
#include <sys/types.h>
#include <taskman.h>
#include <unistd.h>
#include <vfs/vfs.h>
#include <vfs/inbox.h>
#include <libc.h>

#ifdef CONFIG_RTLD
#include <rtld/rtld.h>
#endif

#define DPRINTF(...) ((void) 0)

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

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

/** Primary IPC session */
static async_sess_t *session_primary = NULL;

/** 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;

/** Ensure synchronization of handshake and connection fibrils. */
static bool handshake_complete = false;
FIBRIL_MUTEX_INITIALIZE(handshake_mtx);
FIBRIL_CONDVAR_INITIALIZE(handshake_cv);

static void ldr_get_taskid(ipc_call_t *req)
{
        ipc_call_t call;
        task_id_t task_id;
        size_t len;

        task_id = task_get_id();

        if (!async_data_read_receive(&call, &len)) {
                async_answer_0(&call, EINVAL);
                async_answer_0(req, EINVAL);
                return;
        }

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

        DPRINTF("LOADER_GET_TASKID() = %lu\n", (unsigned long) task_id);
        async_data_read_finalize(&call, &task_id, len);
        async_answer_0(req, EOK);
}

/** Receive a call setting the current working directory.
 *
 */
static void ldr_set_cwd(ipc_call_t *req)
{
        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;
        }

        DPRINTF("LOADER_SET_CWD('%s')\n", cwd);
        async_answer_0(req, rc);
}

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

        char *name = malloc(namesize);
        // FIXME: check return value

        errno_t rc = async_data_write_finalize(&call, name, namesize);
        if (rc != EOK) {
                async_answer_0(req, EINVAL);
                return;
        }

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

        DPRINTF("LOADER_SET_PROGRAM('%s')\n", name);

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

/** Receive a call setting arguments of the program to execute.
 *
 */
static void ldr_set_args(ipc_call_t *req)
{
        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, 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);

                for (int i = 0; i < count; i++)
                        DPRINTF("LOADER_SET_ARGS('%s')\n", _argv[i]);

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

        async_answer_0(req, rc);
}

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

        ipc_call_t call;
        size_t namesize;
        if (!async_data_write_receive(&call, &namesize)) {
                async_answer_0(req, EINVAL);
                return;
        }

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

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

        DPRINTF("LOADER_ADD_INBOX('%s')\n", name);

        /*
         * 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, EOK);
}

/** Load the previously selected program.
 *
 * @return 0 on success, !0 on error.
 *
 */
static int ldr_load(ipc_call_t *req)
{
        DPRINTF("LOADER_LOAD()\n");

        errno_t rc = elf_load(program_fd, &prog_info);
        if (rc != EOK) {
                DPRINTF("Failed to load executable for '%s'.\n", progname);
                async_answer_0(req, EINVAL);
                return 1;
        }

        DPRINTF("Loaded.\n");

#ifdef CONFIG_RTLD
        if (prog_info.env) {
                pcb.tcb = rtld_tls_make(prog_info.env);
        } else {
                pcb.tcb = tls_make(prog_info.finfo.base);
        }
#else
        pcb.tcb = tls_make(prog_info.finfo.base);
#endif

        if (!pcb.tcb) {
                DPRINTF("Failed to make TLS for '%s'.\n", progname);
                async_answer_0(req, ENOMEM);
                return 1;
        }

        elf_set_pcb(&prog_info, &pcb);

        DPRINTF("PCB set.\n");

        pcb.session_primary = session_primary;

        pcb.cwd = cwd;

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

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

        DPRINTF("Answering.\n");
        async_answer_0(req, EOK);
        return 0;
}

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

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

        /* Run program */
        DPRINTF("Reply OK\n");
        async_answer_0(req, EOK);

        /*
         * Wait for the hangup from the other side in order not to leave any
         * unanswered IPC_M_PHONE_HUNGUP messages behind.
         */
        async_get_call(req);
        assert(!ipc_get_imethod(req));
        async_answer_0(req, EOK);

        DPRINTF("Jump to entry point at %p\n", pcb.entry);

        __libc_fini();
        __tcb_reset();
        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(ipc_call_t *icall, void *arg)
{
        /* Wait for handshake */
        fibril_mutex_lock(&handshake_mtx);
        while (!handshake_complete) {
                fibril_condvar_wait(&handshake_cv, &handshake_mtx);
        }
        fibril_mutex_unlock(&handshake_mtx);

        /* Already have a connection? */
        if (connected) {
                async_answer_0(icall, ELIMIT);
                return;
        }

        connected = true;

        /* Accept the connection */
        async_accept_0(icall);

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

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

                if (!ipc_get_imethod(&call)) {
                        async_answer_0(&call, EOK);
                        exit(0);
                }

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

                async_answer_0(&call, retval);
        }
}

static errno_t ldr_taskman_handshake(void)
{
        errno_t retval = EOK;

        fibril_mutex_lock(&handshake_mtx);
        session_primary = taskman_handshake();
        if (session_primary == NULL) {
                retval = errno;
                goto finish;
        }

        async_sess_t *session_tm = async_session_primary_swap(session_primary);
        (void)async_hangup(session_tm);

        handshake_complete = true;

finish:
        fibril_condvar_signal(&handshake_cv);
        fibril_mutex_unlock(&handshake_mtx);

        return retval;
}

/** Program loader main function.
 */
int main(int argc, char *argv[])
{
        /* Set a handler of incomming connections. */
        async_set_fallback_port_handler(ldr_connection, NULL);
        
        /* Handshake with taskman */
        int rc = ldr_taskman_handshake();
        if (rc != EOK) {
                DPRINTF("Failed taskman handshake (%i).\n", errno);
                return rc;
        }

        /* Handle client connections */
        async_manager();
        //TODO retval?
        
        /* Never reached */
        return 0;
}

/** @}
 */