source: mainline/uspace/lib/c/generic/task.c@ b8341bc

/*
 * Copyright (c) 2006 Jakub Jermar
 * Copyright (c) 2008 Jiri Svoboda
 * Copyright (c) 2014 Martin Sucha
 * Copyright (c) 2015 Michal Koutny
 * 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 libc
 * @{
 */
/** @file
 */

#include <assert.h>
#include <async.h>
#include <errno.h>
#include <ns.h>
#include <stdlib.h>
#include <ipc/taskman.h>
#include <libc.h>
#include <loader/loader.h>
#include <macros.h>
#include <malloc.h>
#include <stdarg.h>
#include <str.h>
#include <task.h>
#include <vfs/vfs.h>
#include "private/ns.h"
#include "private/task.h"

static async_sess_t *session_taskman = NULL;
static task_event_handler_t task_event_handler = NULL;

task_id_t task_get_id(void)
{
#ifdef __32_BITS__
        task_id_t task_id;
        (void) __SYSCALL1(SYS_TASK_GET_ID, (sysarg_t) &task_id);

        return task_id;
#endif  /* __32_BITS__ */

#ifdef __64_BITS__
        return (task_id_t) __SYSCALL0(SYS_TASK_GET_ID);
#endif  /* __64_BITS__ */
}

static async_exch_t *taskman_exchange_begin(void)
{
        /* Lazy connection */
        if (session_taskman == NULL) {
                // TODO unify exchange mgmt with taskman_handshake/__init
                session_taskman = service_connect_blocking(EXCHANGE_SERIALIZE,
                    SERVICE_TASKMAN,
                    TASKMAN_CONTROL,
                    0);
        }

        if (session_taskman == NULL) {
                return NULL;
        }

        async_exch_t *exch = async_exchange_begin(session_taskman);
        return exch;
}

static void taskman_exchange_end(async_exch_t *exch)
{
        async_exchange_end(exch);
}

/** Set the task name.
 *
 * @param name The new name, typically the command used to execute the
 *             program.
 *
 * @return Zero on success or an error code.
 */
errno_t task_set_name(const char *name)
{
        assert(name);

        return (errno_t) __SYSCALL2(SYS_TASK_SET_NAME, (sysarg_t) name, str_size(name));
}

/** Kill a task.
 *
 * @param task_id ID of task to kill.
 *
 * @return Zero on success or an error code.
 */

errno_t task_kill(task_id_t task_id)
{
        return (errno_t) __SYSCALL1(SYS_TASK_KILL, (sysarg_t) &task_id);
}

/** Setup waiting for a task.
 *
 * If the task finishes after this call succeeds, it is guaranteed that
 * task_wait(wait, &texit, &retval) will return correct return value for
 * the task.
 *
 * @param id   ID of the task to setup waiting for.
 * @param wait Information necessary for the later task_wait call is stored here.
 *
 * @return EOK on success, else error code.
 * @return TODO check this doesn't return EINVAL -- clash with task_wait
 */
static errno_t task_setup_wait(task_id_t id, task_wait_t *wait)
{
        assert(wait->flags);
        if (wait->flags & TASK_WAIT_BOTH) {
                wait->flags |= (TASK_WAIT_RETVAL | TASK_WAIT_EXIT);
        }
        wait->tid = id;
        async_exch_t *exch = taskman_exchange_begin();
        if (exch == NULL)
                        return EIO;

        wait->aid = async_send_3(exch, TASKMAN_WAIT, LOWER32(id), UPPER32(id),
            wait->flags, &wait->result);
        taskman_exchange_end(exch);

        return EOK;
}

/** Create a new task by running an executable from the filesystem.
 *
 * This is really just a convenience wrapper over the more complicated
 * loader API. Arguments are passed as a null-terminated array of strings.
 *
 * @param id   If not NULL, the ID of the task is stored here on success.
 * @param wait If not NULL, setup waiting for task's return value and store
 *             the information necessary for waiting here on success.
 * @param path Pathname of the binary to execute.
 * @param argv Command-line arguments.
 *
 * @return Zero on success or an error code.
 *
 */
errno_t task_spawnv(task_id_t *id, task_wait_t *wait, const char *path,
    const char *const args[])
{
        /* Send default files */

        int fd_stdin = -1;
        int fd_stdout = -1;
        int fd_stderr = -1;

        if (stdin != NULL) {
                (void) vfs_fhandle(stdin, &fd_stdin);
        }

        if (stdout != NULL) {
                (void) vfs_fhandle(stdout, &fd_stdout);
        }

        if (stderr != NULL) {
                (void) vfs_fhandle(stderr, &fd_stderr);
        }

        return task_spawnvf(id, wait, path, args, fd_stdin, fd_stdout,
            fd_stderr);
}

/** Create a new task by running an executable from the filesystem.
 *
 * This is really just a convenience wrapper over the more complicated
 * loader API. Arguments are passed as a null-terminated array of strings.
 * Files are passed as null-terminated array of pointers to fdi_node_t.
 *
 * @param id      If not NULL, the ID of the task is stored here on success.
 * @param wait    If not NULL, setup waiting for task's return value and store
 * @param path    Pathname of the binary to execute.
 * @param argv    Command-line arguments.
 * @param std_in  File to use as stdin.
 * @param std_out File to use as stdout.
 * @param std_err File to use as stderr.
 *
 * @return Zero on success or an error code.
 *
 */
errno_t task_spawnvf(task_id_t *id, task_wait_t *wait, const char *path,
    const char *const args[], int fd_stdin, int fd_stdout, int fd_stderr)
{
        /* Connect to a program loader. */
        loader_t *ldr = loader_connect();
        if (ldr == NULL)
                return EREFUSED;

        bool wait_initialized = false;

        /* Get task ID. */
        task_id_t task_id;
        errno_t rc = loader_get_task_id(ldr, &task_id);
        if (rc != EOK)
                goto error;

        /* Send spawner's current working directory. */
        rc = loader_set_cwd(ldr);
        if (rc != EOK)
                goto error;

        /* Send program binary. */
        rc = loader_set_program_path(ldr, path);
        if (rc != EOK)
                goto error;

        /* Send arguments. */
        rc = loader_set_args(ldr, args);
        if (rc != EOK)
                goto error;

        /* Send files */
        int root = vfs_root();
        if (root >= 0) {
                rc = loader_add_inbox(ldr, "root", root);
                vfs_put(root);
                if (rc != EOK)
                        goto error;
        }

        if (fd_stdin >= 0) {
                rc = loader_add_inbox(ldr, "stdin", fd_stdin);
                if (rc != EOK)
                        goto error;
        }

        if (fd_stdout >= 0) {
                rc = loader_add_inbox(ldr, "stdout", fd_stdout);
                if (rc != EOK)
                        goto error;
        }

        if (fd_stderr >= 0) {
                rc = loader_add_inbox(ldr, "stderr", fd_stderr);
                if (rc != EOK)
                        goto error;
        }

        /* Load the program. */
        rc = loader_load_program(ldr);
        if (rc != EOK)
                goto error;

        /* Setup waiting for return value if needed */
        if (wait) {
                rc = task_setup_wait(task_id, wait);
                if (rc != EOK)
                        goto error;
                wait_initialized = true;
        }

        /* Run it. */
        rc = loader_run(ldr);
        if (rc != EOK)
                goto error;

        /* Success */
        if (id != NULL)
                *id = task_id;

        return EOK;

error:
        if (wait_initialized)
                task_cancel_wait(wait);

        /* Error exit */
        loader_abort(ldr);
        return rc;
}

/** Create a new task by running an executable from the filesystem.
 *
 * This is really just a convenience wrapper over the more complicated
 * loader API. Arguments are passed in a va_list.
 *
 * @param id   If not NULL, the ID of the task is stored here on success.
 * @param wait If not NULL, setup waiting for task's return value and store
 *             the information necessary for waiting here on success.
 * @param path Pathname of the binary to execute.
 * @param cnt  Number of arguments.
 * @param ap   Command-line arguments.
 *
 * @return Zero on success or an error code.
 *
 */
errno_t task_spawn(task_id_t *task_id, task_wait_t *wait, const char *path,
    int cnt, va_list ap)
{
        /* Allocate argument list. */
        const char **arglist = malloc(cnt * sizeof(const char *));
        if (arglist == NULL)
                return ENOMEM;

        /* Fill in arguments. */
        const char *arg;
        cnt = 0;
        do {
                arg = va_arg(ap, const char *);
                arglist[cnt++] = arg;
        } while (arg != NULL);

        /* Spawn task. */
        errno_t rc = task_spawnv(task_id, wait, path, arglist);

        /* Free argument list. */
        free(arglist);
        return rc;
}

/** Create a new task by running an executable from the filesystem.
 *
 * This is really just a convenience wrapper over the more complicated
 * loader API. Arguments are passed as a null-terminated list of arguments.
 *
 * @param id   If not NULL, the ID of the task is stored here on success.
 * @param wait If not NULL, setup waiting for task's return value and store
 *             the information necessary for waiting here on success.
 * @param path Pathname of the binary to execute.
 * @param ...  Command-line arguments.
 *
 * @return Zero on success or an error code.
 *
 */
errno_t task_spawnl(task_id_t *task_id, task_wait_t *wait, const char *path, ...)
{
        /* Count the number of arguments. */

        va_list ap;
        const char *arg;
        int cnt = 0;

        va_start(ap, path);
        do {
                arg = va_arg(ap, const char *);
                cnt++;
        } while (arg != NULL);
        va_end(ap);

        va_start(ap, path);
        errno_t rc = task_spawn(task_id, wait, path, cnt, ap);
        va_end(ap);

        return rc;
}

/** Cancel waiting for a task.
 *
 * This can be called *instead of* task_wait if the caller is not interested
 * in waiting for the task anymore.
 *
 * This function cannot be called if the task_wait was already called.
 *
 * @param wait task_wait_t previously initialized by task_setup_wait.
 */
void task_cancel_wait(task_wait_t *wait)
{
        async_forget(wait->aid);
}

/** Wait for a task to finish.
 *
 * This function returns correct values even if the task finished in
 * between task_setup_wait and this task_wait call.
 *
 * This function cannot be called more than once with the same task_wait_t
 * (it can be reused, but must be reinitialized with task_setup_wait first)
 *
 * @param wait   task_wait_t previously initialized by task_setup_wait.
 * @param texit  Store type of task exit here.
 * @param retval Store return value of the task here.
 *
 * @return EOK on success
 * @return EINVAL on lost wait TODO other error codes
 */
errno_t task_wait(task_wait_t *wait, task_exit_t *texit, int *retval)
{
        errno_t rc;
        async_wait_for(wait->aid, &rc);

        if (rc == EOK || rc == EINVAL) {
                if (wait->flags & TASK_WAIT_EXIT && texit)
                        *texit = ipc_get_arg1(wait->result);
                if (wait->flags & TASK_WAIT_RETVAL && retval)
                        *retval = ipc_get_arg2(wait->result);
                
        }

        if (rc == EOK) {
                /* Is there another wait to be done? Wait for it! */
                int old_flags = wait->flags;
                wait->flags = ipc_get_arg3(wait->result);
                if (wait->flags != 0 && (old_flags & TASK_WAIT_BOTH)) {
                        rc = task_setup_wait(wait->tid, wait);
                }
        } else {
                wait->flags = 0;
        }

        return rc;
}

/** Wait for a task to finish by its id.
 *
 * Note that this will fail with ENOENT if the task id is not registered in ns
 * (e.g. if the task finished). If you are spawning a task and need to wait
 * for its completion, use wait parameter of the task_spawn* functions instead
 * to prevent a race where the task exits before you may have a chance to wait
 * wait for it.
 *
 * @param id ID of the task to wait for.
 * @param flags  Specify for which task output we wait
 * @param texit  Store type of task exit here.
 * @param retval Store return value of the task here.
 *
 * @return EOK on success, else error code.
 */
errno_t task_wait_task_id(task_id_t id, int flags, task_exit_t *texit, int *retval)
{
        task_wait_t wait;
        wait.flags = flags;
        errno_t rc = task_setup_wait(id, &wait);

        if (rc != EOK)
                return rc;

        return task_wait(&wait, texit, retval);
}

errno_t task_retval_internal(int val, bool wait_for_exit)
{
        async_exch_t *exch = taskman_exchange_begin();
        if (exch == NULL)
                return EIO;

        errno_t rc = (int) async_req_2_0(exch, TASKMAN_RETVAL, val, wait_for_exit);
        taskman_exchange_end(exch);
        
        return rc;
}

errno_t task_retval(int val)
{
        return task_retval_internal(val, false);
}

// TODO extract to separate module
static void taskman_task_event(ipc_callid_t iid, ipc_call_t *icall)
{
        task_id_t tid = (task_id_t)
            MERGE_LOUP32(IPC_GET_ARG1(*icall), IPC_GET_ARG2(*icall));
        int flags = IPC_GET_ARG3(*icall);
        task_exit_t texit = IPC_GET_ARG4(*icall);
        int retval = IPC_GET_ARG5(*icall);

        task_event_handler(tid, flags, texit, retval);

        async_answer_0(iid, EOK);
}

static void taskman_event_conn(ipc_callid_t iid, ipc_call_t *icall, void *arg)
{
        /* Accept connection */
        async_answer_0(iid, EOK);

        while (true) {
                ipc_call_t call;
                ipc_callid_t callid = async_get_call(&call);

                if (!IPC_GET_IMETHOD(call)) {
                        /* Hangup, TODO explain or handle differntly */
                        break;
                }

                switch (IPC_GET_IMETHOD(call)) {
                case TASKMAN_EV_TASK:
                        taskman_task_event(callid, &call);
                        break;
                default:
                        async_answer_0(callid, ENOTSUP);
                        break;
                }
        }
}

/**
 * Blocks, calls handler in another fibril
 */
int task_register_event_handler(task_event_handler_t handler)
{
        /*
         * so far support assign once, modification cannot be naïve due to
         * races
         */
        assert(task_event_handler == NULL);
        assert(handler != NULL); /* no support for "unregistration" */

        task_event_handler = handler;

        async_exch_t *exch = taskman_exchange_begin();
        aid_t req = async_send_0(exch, TASKMAN_EVENT_CALLBACK, NULL);

        int rc = async_connect_to_me(exch, 0, 0, 0, taskman_event_conn, NULL);
        taskman_exchange_end(exch);

        if (rc != EOK) {
                return rc;
        }

        sysarg_t retval;
        async_wait_for(req, &retval);
        return retval;
}

void __task_init(async_sess_t *sess)
{
        assert(session_taskman == NULL);
        session_taskman = sess;
}

/** @}
 */