src/process.h

   1 /* process.h -- header for child process routines for vlock,
   2  *              the VT locking program for linux
   3  *
   4  * This program is copyright (C) 2007 Frank Benkstein, and is free
   5  * software which is freely distributable under the terms of the
   6  * GNU General Public License version 2, included as the file COPYING in this
   7  * distribution.  It is NOT public domain software, and any
   8  * redistribution not permitted by the GNU General Public License is
   9  * expressly forbidden without prior written permission from
  10  * the author.
  11  *
  12  */
  13
  14 #pragma once
  15
  16 #include <stdbool.h>
  17 #include <sys/types.h>
  18 #include <glib.h>
  19
  20 /* Errors */
  21 #define VLOCK_PROCESS_ERROR vlock_process_error_quark()
  22 GQuark vlock_process_error_quark(void);
  23
  24 enum {
  25   VLOCK_PROCESS_ERROR_FAILED,
  26   VLOCK_PROCESS_ERROR_NOT_FOUND,
  27 };
  28
  29 /* Wait for the given amount of time for the death of the given child process.
  30  * If the child process dies in the given amount of time or already was dead
  31  * true is returned and false otherwise. */
  32 bool wait_for_death(pid_t pid, long sec, long usec);
  33
  34 /* Try hard to kill the given child process. */
  35 void ensure_death(pid_t pid);
  36
  37 #define NO_REDIRECT (-2)
  38 #define REDIRECT_DEV_NULL (-3)
  39 #define REDIRECT_PIPE (-4)
  40
  41 struct child_process
  42 {
  43   /* Function that will be run in the child. */
  44   int (*function)(void *argument);
  45   /* Argument for the function. */
  46   void *argument;
  47   /* First argument to execv. */
  48   const char *path;
  49   /* Second argument to execv. */
  50   const char *const *argv;
  51   /* The child's stdin. */
  52   int stdin_fd;
  53   /* The child's stdout. */
  54   int stdout_fd;
  55   /* The child's stderr. */
  56   int stderr_fd;
  57   /* The child's PID. */
  58   pid_t pid;
  59 };
  60
  61 /* Create a new child process.  All file descriptors except stdin, stdout and
  62  * stderr are closed and privileges are dropped.  All fields of the child
  63  * struct except pid must be set.  If a stdio file descriptor field has the
  64  * special value of REDIRECT_DEV_NULL it is redirected from or to /dev/null.
  65  * If it has the value REDIRECT_PIPE a pipe will be created and one end will be
  66  * connected to the respective descriptor of the child.  The file descriptor of
  67  * the other end is stored in the field after the call.  It is up to the caller
  68  * to close the pipe descriptor(s). */
  69 bool create_child(struct child_process *child, GError **error);