/**************************************************************************** * apps/nshlib/nsh_builtin.c * * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. The * ASF licenses this file to you under the Apache License, Version 2.0 (the * "License"); you may not use this file except in compliance with the * License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the * License for the specific language governing permissions and limitations * under the License. * ****************************************************************************/ /**************************************************************************** * Included Files ****************************************************************************/ #include #ifdef CONFIG_SCHED_WAITPID # include # include #endif #include #include #include #include #include "builtin/builtin.h" #include "nsh.h" #include "nsh_console.h" #ifdef CONFIG_NSH_BUILTIN_APPS /**************************************************************************** * Public Functions ****************************************************************************/ /**************************************************************************** * Name: nsh_builtin * * Description: * Attempt to execute the application task whose name is 'cmd' * * Returned Value: * <0 If exec_builtin() fails, then the negated errno value * is returned. * -1 (ERROR) if the application task corresponding to 'cmd' could not * be started (possibly because it doesn not exist). * 0 (OK) if the application task corresponding to 'cmd' was * and successfully started. If CONFIG_SCHED_WAITPID is * defined, this return value also indicates that the * application returned successful status (EXIT_SUCCESS) * 1 If CONFIG_SCHED_WAITPID is defined, then this return value * indicates that the application task was spawned successfully * but returned failure exit status. * ****************************************************************************/ int nsh_builtin(FAR struct nsh_vtbl_s *vtbl, FAR const char *cmd, FAR char **argv, FAR const char *redirfile, int oflags) { #if !defined(CONFIG_NSH_DISABLEBG) && defined(CONFIG_SCHED_CHILD_STATUS) struct sigaction act; struct sigaction old; #endif int ret = OK; /* Lock the scheduler in an attempt to prevent the application from * running until waitpid() has been called. */ sched_lock(); #if !defined(CONFIG_NSH_DISABLEBG) && defined(CONFIG_SCHED_CHILD_STATUS) /* Ignore the child status if run the application on background. */ if (vtbl->np.np_bg == true) { act.sa_handler = SIG_DFL; act.sa_flags = SA_NOCLDWAIT; sigemptyset(&act.sa_mask); sigaction(SIGCHLD, &act, &old); } #endif /* CONFIG_NSH_DISABLEBG */ /* Try to find and execute the command within the list of builtin * applications. */ ret = exec_builtin(cmd, (FAR char * const *)argv, redirfile, oflags); if (ret >= 0) { /* The application was successfully started with pre-emption disabled. * In the simplest cases, the application will not have run because the * the scheduler is locked. But in the case where I/O was redirected, * a proxy task ran and broke our lock. As result, the application may * have aso ran if its priority was higher than than the priority of * this thread. * * If the application did not run to completion and if the application * was not backgrounded, then we need to wait here for the application * to exit. This only works works with the following options: * * - CONFIG_NSH_DISABLEBG - Do not run commands in background * - CONFIG_SCHED_WAITPID - Required to run external commands in * foreground */ #ifdef CONFIG_SCHED_WAITPID /* CONFIG_SCHED_WAITPID is selected, so we may run the command in * foreground unless we were specifically requested to run the command * in background (and running commands in background is enabled). */ # ifndef CONFIG_NSH_DISABLEBG if (vtbl->np.np_bg == false) # endif /* CONFIG_NSH_DISABLEBG */ { int rc = 0; int tc = 0; if (vtbl->isctty) { /* Setup up to receive SIGINT if control-C entered. */ tc = ioctl(stdout->fs_fd, TIOCSCTTY, ret); } /* Wait for the application to exit. We did lock the scheduler * above, but that does not guarantee that the application did not * already run to completion in the case where I/O was redirected. * Here the scheduler will be unlocked while waitpid is waiting * and if the application has not yet run, it will now be able to * do so. * * Also, if CONFIG_SCHED_HAVE_PARENT is defined waitpid() might * fail even if task is still active: If the I/O was re-directed * by a proxy task, then the ask is a child of the proxy, and not * this task. waitpid() fails with ECHILD in either case. * * NOTE: WUNTRACED does nothing in the default case, but in the * case the where CONFIG_SIG_SIGSTOP_ACTION=y, the built-in app * may also be stopped. In that case WUNTRACED will force * waitpid() to return with ECHILD. */ ret = waitpid(ret, &rc, WUNTRACED); if (ret < 0) { /* If the child thread does not exist, waitpid() will return * the error ECHLD. Since we know that the task was * successfully started, this must be one of the cases * described above; we have to assume that the task already * exit'ed. In this case, we have no idea if the application * ran successfully or not (because NuttX does not retain exit * status of child tasks). Let's assume that is did run * successfully. */ int errcode = errno; if (errcode == ECHILD) { ret = OK; } else { nsh_error(vtbl, g_fmtcmdfailed, cmd, "waitpid", NSH_ERRNO_OF(errcode)); } } /* Waitpid completed the wait successfully */ else { /* We can't return the exact status (nsh has nowhere to put it) * so just pass back zero/nonzero in a fashion that doesn't * look like an error. */ ret = (rc == 0) ? OK : 1; /* TODO: Set the environment variable '?' to a string * corresponding to WEXITSTATUS(rc) so that $? will expand to * the exit status of the most recently executed task. */ } if (vtbl->isctty && tc == 0) { ioctl(stdout->fs_fd, TIOCNOTTY); } } # ifndef CONFIG_NSH_DISABLEBG else # endif /* CONFIG_NSH_DISABLEBG */ #endif /* CONFIG_SCHED_WAITPID */ /* We get here if either: * * - CONFIG_SCHED_WAITPID is not selected meaning that all commands * have to be run in background, or * - CONFIG_SCHED_WAITPID and CONFIG_NSH_DISABLEBG are both selected, * but the user requested to run the command in background. * * NOTE that the case of a) CONFIG_SCHED_WAITPID is not selected and * b) CONFIG_NSH_DISABLEBG selected cannot be supported. In that * event, all commands will have to run in background. The waitpid() * API must be available to support running the command in foreground. */ #if !defined(CONFIG_SCHED_WAITPID) || !defined(CONFIG_NSH_DISABLEBG) { #if !defined(CONFIG_NSH_DISABLEBG) && defined(CONFIG_SCHED_CHILD_STATUS) /* Restore the old actions */ sigaction(SIGCHLD, &old, NULL); # endif struct sched_param param; sched_getparam(ret, ¶m); nsh_output(vtbl, "%s [%d:%d]\n", cmd, ret, param.sched_priority); /* Backgrounded commands always 'succeed' as long as we can start * them. */ ret = OK; } #endif /* !CONFIG_SCHED_WAITPID || !CONFIG_NSH_DISABLEBG */ } sched_unlock(); /* If exec_builtin() or waitpid() failed, then return -1 (ERROR) with the * errno value set appropriately. */ if (ret < 0) { return ERROR; } return ret; } #endif /* CONFIG_NSH_BUILTIN_APPS */