source: mainline/uspace/srv/loader/main.c@ c98e6ee

/*
 * 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 <unistd.h>
#include <fcntl.h>
#include <sys/types.h>
#include <ipc/ipc.h>
#include <ipc/loader.h>
#include <loader/pcb.h>
#include <errno.h>
#include <async.h>
#include <as.h>

#include <elf.h>
#include <elf_load.h>

/** 
 * Bias used for loading the dynamic linker. This will be soon replaced
 * by automatic placement.
 */
#define RTLD_BIAS 0x80000

/** Pathname of the file that will be loaded */
static char *pathname = NULL;

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

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

/** Receive a call setting pathname of the program to execute.
 *
 * @param rid
 * @param request
 */
static void loader_set_pathname(ipc_callid_t rid, ipc_call_t *request)
{
        ipc_callid_t callid;
        size_t len;
        char *name_buf;

        if (!ipc_data_write_receive(&callid, &len)) {
                ipc_answer_0(callid, EINVAL);
                ipc_answer_0(rid, EINVAL);
                return;
        }

        name_buf = malloc(len + 1);
        if (!name_buf) {
                ipc_answer_0(callid, ENOMEM);
                ipc_answer_0(rid, ENOMEM);
                return;
        }

        ipc_data_write_finalize(callid, name_buf, len);
        ipc_answer_0(rid, EOK);

        if (pathname != NULL) {
                free(pathname);
                pathname = NULL;
        }

        name_buf[len] = '\0';
        pathname = name_buf;
}

/** Receive a call setting arguments of the program to execute.
 *
 * @param rid
 * @param request
 */
static void loader_set_args(ipc_callid_t rid, ipc_call_t *request)
{
        ipc_callid_t callid;
        size_t buf_len, arg_len;
        char *p;
        int n;

        if (!ipc_data_write_receive(&callid, &buf_len)) {
                ipc_answer_0(callid, EINVAL);
                ipc_answer_0(rid, EINVAL);
                return;
        }

        if (arg_buf != NULL) {
                free(arg_buf);
                arg_buf = NULL;
        }

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

        arg_buf = malloc(buf_len + 1);
        if (!arg_buf) {
                ipc_answer_0(callid, ENOMEM);
                ipc_answer_0(rid, ENOMEM);
                return;
        }

        ipc_data_write_finalize(callid, arg_buf, buf_len);
        ipc_answer_0(rid, EOK);

        arg_buf[buf_len] = '\0';

        /*
         * Count number of arguments
         */
        p = arg_buf;
        n = 0;
        while (p < arg_buf + buf_len) {
                arg_len = strlen(p);
                p = p + arg_len + 1;
                ++n;
        }

        /* Allocate argv */
        argv = malloc((n + 1) * sizeof(char *));

        if (argv == NULL) {
                free(arg_buf);
                ipc_answer_0(callid, ENOMEM);
                ipc_answer_0(rid, ENOMEM);
                return;
        }

        /*
         * Fill argv with argument pointers
         */
        p = arg_buf;
        n = 0;
        while (p < arg_buf + buf_len) {
                argv[n] = p;

                arg_len = strlen(p);
                p = p + arg_len + 1;
                ++n;
        }

        argc = n;
        argv[n] = NULL;
}


/** Load and run the previously selected program.
 *
 * @param rid
 * @param request
 * @return 0 on success, !0 on error.
 */
static int loader_run(ipc_callid_t rid, ipc_call_t *request)
{
        int rc;

        elf_info_t prog_info;
        elf_info_t interp_info;

//      printf("Load program '%s'\n", pathname);

        rc = elf_load_file(pathname, 0, &prog_info);
        if (rc < 0) {
                printf("failed to load program\n");
                ipc_answer_0(rid, EINVAL);
                return 1;
        }

//      printf("Create PCB\n");
        elf_create_pcb(&prog_info, &pcb);

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

        if (prog_info.interp == NULL) {
                /* Statically linked program */
//              printf("Run statically linked program\n");
//              printf("entry point: 0x%llx\n", prog_info.entry);
                ipc_answer_0(rid, EOK);
                close_console();
                elf_run(&prog_info, &pcb);
                return 0;
        }

        printf("Load dynamic linker '%s'\n", prog_info.interp);
        rc = elf_load_file("/rtld.so", RTLD_BIAS, &interp_info);
        if (rc < 0) {
                printf("failed to load dynamic linker\n");
                ipc_answer_0(rid, EINVAL);
                return 1;
        }

        /*
         * Provide dynamic linker with some useful data
         */
        pcb.rtld_dynamic = interp_info.dynamic;
        pcb.rtld_bias = RTLD_BIAS;

        printf("run dynamic linker\n");
        printf("entry point: 0x%llx\n", interp_info.entry);
        close_console();

        ipc_answer_0(rid, EOK);
        elf_run(&interp_info, &pcb);

        /* Not reached */
        return 0;
}

/** Handle loader connection.
 *
 * Receive and carry out commands (of which the last one should be
 * to execute the loaded program).
 */
static void loader_connection(ipc_callid_t iid, ipc_call_t *icall)
{
        ipc_callid_t callid;
        ipc_call_t call;
        int retval;

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

        while (1) {
                callid = async_get_call(&call);
//              printf("received call from phone %d, method=%d\n",
//                      call.in_phone_hash, IPC_GET_METHOD(call));
                switch (IPC_GET_METHOD(call)) {
                case LOADER_SET_PATHNAME:
                        loader_set_pathname(callid, &call);
                        continue;
                case LOADER_SET_ARGS:
                        loader_set_args(callid, &call);
                case LOADER_RUN:
                        loader_run(callid, &call);
                        exit(0);
                        continue;
                default:
                        retval = ENOENT;
                        break;
                }
                if ((callid & IPC_CALLID_NOTIFICATION) == 0 &&
                    IPC_GET_METHOD(call) != IPC_M_PHONE_HUNGUP) {
                        printf("responding EINVAL to method %d\n", 
                            IPC_GET_METHOD(call));
                        ipc_answer_0(callid, EINVAL);
                }
        }
}

/** Program loader main function.
 */
int main(int argc, char *argv[])
{
        ipc_callid_t callid;
        ipc_call_t call;
        ipcarg_t phone_hash;

        /* The first call only communicates the incoming phone hash */
        callid = ipc_wait_for_call(&call);

        if (IPC_GET_METHOD(call) != LOADER_HELLO) {
                if (IPC_GET_METHOD(call) != IPC_M_PHONE_HUNGUP)
                        ipc_answer_0(callid, EINVAL);
                return 1;
        }

        ipc_answer_0(callid, EOK);
        phone_hash = call.in_phone_hash;

        /* 
         * Up until now async must not be used as it couldn't
         * handle incoming requests. (Which means e.g. printf() 
         * cannot be used)
         */
        async_new_connection(phone_hash, 0, NULL, loader_connection);
        async_manager();

        /* not reached */
        return 0;
}

/** @}
 */