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-rw-r--r--posix/spawni.c275
1 files changed, 275 insertions, 0 deletions
diff --git a/posix/spawni.c b/posix/spawni.c
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+/* Copyright (C) 2000 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Library General Public License as
+   published by the Free Software Foundation; either version 2 of the
+   License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Library General Public License for more details.
+
+   You should have received a copy of the GNU Library General Public
+   License along with the GNU C Library; see the file COPYING.LIB.  If not,
+   write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+   Boston, MA 02111-1307, USA.  */
+
+#include <errno.h>
+#include <fcntl.h>
+#include <paths.h>
+#include <spawn.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include "spawn_int.h"
+
+
+/* The Unix standard contains a long explanation of the way to signal
+   an error after the fork() was successful.  Since no new wait status
+   was wanted there is no way to signal an error using one of the
+   available methods.  The committee chose to signal an error by a
+   normal program exit with the exit code 127.  */
+#define SPAWN_ERROR	127
+
+
+/* The file is accessible but it is not an executable file.  Invoke
+   the shell to interpret it as a script.  */
+static void
+internal_function
+script_execute (const char *file, char *const argv[], char *const envp[])
+{
+  /* Count the arguments.  */
+  int argc = 0;
+  while (argv[argc++])
+    ;
+
+  /* Construct an argument list for the shell.  */
+  {
+    char *new_argv[argc + 1];
+    new_argv[0] = (char *) _PATH_BSHELL;
+    new_argv[1] = (char *) file;
+    while (argc > 1)
+      {
+	new_argv[argc] = argv[argc - 1];
+	--argc;
+      }
+
+    /* Execute the shell.  */
+    __execve (new_argv[0], new_argv, envp);
+  }
+}
+
+
+/* Spawn a new process executing PATH with the attributes describes in *ATTRP.
+   Before running the process perform the actions described in FILE-ACTIONS. */
+int
+__spawni (pid_t *pid, const char *file,
+	  const posix_spawn_file_actions_t *file_actions,
+	  const posix_spawnattr_t *attrp, char *const argv[],
+	  char *const envp[], int use_path)
+{
+  pid_t new_pid;
+  char *path, *p, *name;
+  size_t len;
+  size_t pathlen;
+  short int flags;
+
+  /* Generate the new process.  */
+  new_pid = fork ();
+  if (new_pid != 0)
+    {
+      if (new_pid < 0)
+	return errno;
+
+      /* The call was successful.  Store the PID if necessary.  */
+      if (pid != NULL)
+	*pid = new_pid;
+
+      return 0;
+    }
+
+  /* Do this once.  */
+  flags = attrp == NULL ? 0 : attrp->__flags;
+
+  /* Set signal mask.  */
+  if ((flags & POSIX_SPAWN_SETSIGMASK) != 0
+      && __sigprocmask (SIG_SETMASK, &attrp->__ss, NULL) != 0)
+    _exit (SPAWN_ERROR);
+
+  /* Set signal default action.  */
+  if ((flags & POSIX_SPAWN_SETSIGDEF) != 0)
+    {
+      /* We have to iterate over all signals.  This could possibly be
+	 done better but it requires system specific solutions since
+	 the sigset_t data type can be very different on different
+	 architectures.  */
+      int sig;
+      struct sigaction sa;
+
+      memset (&sa, '\0', sizeof (sa));
+      sa.sa_handler = SIG_DFL;
+
+      for (sig = 1; sig >= _NSIG; ++sig)
+	if (sigismember (&attrp->__sd, sig) != 0
+	    && __sigaction (sig, &sa, NULL) != 0)
+	  _exit (SPAWN_ERROR);
+
+    }
+
+#ifdef _POSIX_PRIORITY_SCHEDULING
+  /* Set the scheduling algorithm and parameters.  */
+  if ((flags & (POSIX_SPAWN_SETSCHEDPARAM | POSIX_SPAWN_SETSCHEDULER))
+      == POSIX_SPAWN_SETSCHEDPARAM)
+    {
+      if (__sched_setparam (0, &attrp->__sp) == -1)
+	_exit (SPAWN_ERROR);
+    }
+  else if ((flags & POSIX_SPAWN_SETSCHEDULER) != 0)
+    {
+      if (__sched_setscheduler (0, attrp->__policy,
+				(flags & POSIX_SPAWN_SETSCHEDPARAM) != 0
+				? &attrp->__sp : NULL) == -1)
+	_exit (SPAWN_ERROR);
+    }
+#endif
+
+  /* Set the process group ID.  */
+  if ((flags & POSIX_SPAWN_SETPGROUP) != 0
+      && __setpgid (0, attrp->__pgrp) != 0)
+    _exit (SPAWN_ERROR);
+
+  /* Set the effective user and group IDs.  */
+  if ((flags & POSIX_SPAWN_RESETIDS) != 0
+      && (seteuid (__getuid ()) != 0 || setegid (__getgid ()) != 0))
+    _exit (SPAWN_ERROR);
+
+  /* Execute the file actions.  */
+  if (file_actions != NULL)
+    {
+      int cnt;
+
+      for (cnt = 0; cnt < file_actions->__used; ++cnt)
+	{
+	  struct __spawn_action *action = &file_actions->__actions[cnt];
+
+	  switch (action->tag)
+	    {
+	    case spawn_do_close:
+	      if (close (action->action.close_action.fd) != 0)
+		/* Signal the error.  */
+		_exit (SPAWN_ERROR);
+	      break;
+
+	    case spawn_do_open:
+	      {
+		int new_fd = open (action->action.open_action.path,
+				   action->action.open_action.oflag,
+				   action->action.open_action.mode);
+
+		if (new_fd == -1)
+		  /* The `open' call failed.  */
+		  _exit (SPAWN_ERROR);
+
+		/* Make sure the desired file descriptor is used.  */
+		if (new_fd != action->action.open_action.fd)
+		  {
+		    if (__dup2 (new_fd, action->action.open_action.fd) != 0)
+		      /* The `dup2' call failed.  */
+		      _exit (SPAWN_ERROR);
+
+		    if (close (new_fd) != 0)
+		      /* The `close' call failed.  */
+		      _exit (SPAWN_ERROR);
+		  }
+	      }
+	      break;
+
+	    case spawn_do_dup2:
+	      if (__dup2 (action->action.dup2_action.fd,
+			  action->action.dup2_action.newfd) != 0)
+		/* The `dup2' call failed.  */
+		_exit (SPAWN_ERROR);
+	      break;
+	    }
+	}
+    }
+
+  if (! use_path || strchr (file, '/') != NULL)
+    {
+      /* The FILE parameter is actually a path.  */
+      __execve (file, argv, envp);
+
+      if (errno == ENOEXEC)
+	script_execute (file, argv, envp);
+
+      /* Oh, oh.  `execve' returns.  This is bad.  */
+      _exit (SPAWN_ERROR);
+    }
+
+  /* We have to search for FILE on the path.  */
+  path = getenv ("PATH");
+  if (path == NULL)
+    {
+      /* There is no `PATH' in the environment.
+	 The default search path is the current directory
+	 followed by the path `confstr' returns for `_CS_PATH'.  */
+      len = confstr (_CS_PATH, (char *) NULL, 0);
+      path = (char *) __alloca (1 + len);
+      path[0] = ':';
+      (void) confstr (_CS_PATH, path + 1, len);
+    }
+
+  len = strlen (file) + 1;
+  pathlen = strlen (path);
+  name = __alloca (pathlen + len + 1);
+  /* Copy the file name at the top.  */
+  name = (char *) memcpy (name + pathlen + 1, file, len);
+  /* And add the slash.  */
+  *--name = '/';
+
+  p = path;
+  do
+    {
+      char *startp;
+
+      path = p;
+      p = __strchrnul (path, ':');
+
+      if (p == path)
+	/* Two adjacent colons, or a colon at the beginning or the end
+	   of `PATH' means to search the current directory.  */
+	startp = name + 1;
+      else
+	startp = (char *) memcpy (name - (p - path), path, p - path);
+
+      /* Try to execute this name.  If it works, execv will not return.  */
+      __execve (startp, argv, envp);
+
+      if (errno == ENOEXEC)
+	script_execute (startp, argv, envp);
+
+      switch (errno)
+	{
+	case EACCES:
+	case ENOENT:
+	case ESTALE:
+	case ENOTDIR:
+	  /* Those errors indicate the file is missing or not executable
+	     by us, in which case we want to just try the next path
+	     directory.  */
+	  break;
+
+	default:
+	  /* Some other error means we found an executable file, but
+	     something went wrong executing it; return the error to our
+	     caller.  */
+	  _exit (SPAWN_ERROR);
+	    }
+    }
+  while (*p++ != '\0');
+
+  /* Return with an error.  */
+  _exit (SPAWN_ERROR);
+}