New file. Rewrite of nohup.sh in C.

This solves a portability problem: on at least Solaris systems,
when nohup.sh used the vendor /bin/sh, it would exit with status
of `1' rather than the required 126 or 127 upon failure to exec
the specified program.

diff --git a/src/nohup.c b/src/nohup.c
new file mode 100644 (file)
index 0000000..9c7aeff
--- /dev/null
+++ b/src/nohup.c
@@ -0,0 +1,183 @@
+/* nohup -- run a command immume to hangups, with output to a non-tty
+   Copyright (C) 2003 Free Software Foundation, Inc.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 2, or (at your option)
+   any later version.
+
+   This program 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 General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software Foundation,
+   Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
+
+/* Written by Jim Meyering  */
+
+#include <config.h>
+#include <stdio.h>
+#include <sys/types.h>
+#include <signal.h>
+
+#include "system.h"
+
+#include "closeout.h"
+#include "error.h"
+#include "long-options.h"
+#include "path-concat.h"
+#include "quote.h"
+
+#define PROGRAM_NAME "nohup"
+
+#define AUTHORS "Jim Meyering"
+
+char *program_name;
+
+void
+usage (int status)
+{
+  if (status != 0)
+    fprintf (stderr, _("Try `%s --help' for more information.\n"),
+            program_name);
+  else
+    {
+      printf (_("\
+Usage: %s COMMAND [ARG]...\n\
+  or:  %s OPTION\n\
+"),
+             program_name, program_name);
+
+      fputs (_("\
+Run COMMAND, ignoring hangup signals.\n\
+\n\
+"), stdout);
+      fputs (HELP_OPTION_DESCRIPTION, stdout);
+      fputs (VERSION_OPTION_DESCRIPTION, stdout);
+      printf (_("\nReport bugs to <%s>.\n"), PACKAGE_BUGREPORT);
+    }
+  exit (status);
+}
+
+int
+main (int argc, char **argv)
+{
+  int fd;
+  int saved_stderr_fd = -1;
+  int stderr_isatty;
+
+  initialize_main (&argc, &argv);
+  program_name = argv[0];
+  setlocale (LC_ALL, "");
+  bindtextdomain (PACKAGE, LOCALEDIR);
+  textdomain (PACKAGE);
+
+  atexit (close_stdout);
+
+  parse_long_options (argc, argv, PROGRAM_NAME, GNU_PACKAGE, VERSION,
+                     AUTHORS, usage);
+
+  /* The above handles --help and --version.
+     Now, handle `--'.  */
+  if (argc > 1 && STREQ (argv[1], "--"))
+    {
+      --argc;
+      ++argv;
+    }
+
+  if (argc <= 1)
+    {
+      error (0, 0, _("too few arguments"));
+      usage (EXIT_FAILURE);
+    }
+
+  /* If standard output is a tty, redirect it (appending) to a file.
+     First try nohup.out, then $HOME/nohup.out.  */
+  if (isatty (STDOUT_FILENO))
+    {
+      char *in_home = NULL;
+      char const *file = "nohup.out";
+      int flags = O_CREAT | O_WRONLY | O_APPEND;
+      mode_t mode = S_IRUSR | S_IWUSR;
+      int saved_errno;
+
+      fd = open (file, flags, mode);
+      if (fd == -1)
+       {
+         saved_errno = errno;
+         in_home = path_concat (getenv ("HOME"), file, NULL);
+         fd = open (in_home, flags, mode);
+         if (fd == -1)
+           {
+             int saved_errno2 = errno;
+             error (0, saved_errno, _("failed to open %s"), quote (file));
+             error (0, saved_errno2, _("failed to open %s"), quote (in_home));
+             exit (EXIT_FAILURE);
+           }
+         file = in_home;
+       }
+
+      /* Redirect standard output to the file.  */
+      if (dup2 (fd, STDOUT_FILENO) == -1)
+       error (EXIT_FAILURE, errno, _("failed to redirect standard output"));
+
+      error (0, 0, _("appending output to %s"), quote (file));
+      if (in_home)
+       free (in_home);
+    }
+  else
+    {
+      fd = STDOUT_FILENO;
+    }
+
+  /* If stderr is on a tty, redirect it to stdout.  */
+  if ((stderr_isatty = isatty (STDERR_FILENO)))
+    {
+      /* Save a copy of stderr before redirecting, so we can use the original
+        if execve fails.  It's no big deal if this dup fails.  It might
+        not change anything, and at worst, it'll lead to suppression of
+        the post-failed-execve diagnostic.  */
+      saved_stderr_fd = dup (STDERR_FILENO);
+
+      if (dup2 (fd, STDERR_FILENO) == -1)
+       error (EXIT_FAILURE, errno, _("failed to redirect standard error"));
+    }
+
+  /* Ignore hang-up signals.  */
+  {
+#ifdef _POSIX_SOURCE
+    struct sigaction sigact;
+    sigact.sa_handler = SIG_IGN;
+    sigemptyset (&sigact.sa_mask);
+    sigact.sa_flags = 0;
+    sigaction (SIGHUP, &sigact, NULL);
+#else
+    signal (SIGHUP, SIG_IGN);
+#endif
+  }
+
+  {
+    int exit_status;
+    int saved_errno;
+    char **cmd = argv + 1;
+
+    execvp (*cmd, cmd);
+    exit_status = (errno == ENOENT ? 127 : 126);
+    saved_errno = errno;
+
+    /* The execve failed.  Output a diagnostic to stderr only if:
+       - stderr was initially redirected to a non-tty, or
+       - stderr was initially directed to a tty, and we've
+        just dup2'd it to point back to that same tty.
+       In other words, output the diagnostic if possible, but not if
+       it'd go to nohup.out.  */
+    if ( ! stderr_isatty
+       || (saved_stderr_fd != -1
+           && dup2 (saved_stderr_fd, STDERR_FILENO) != -1))
+      error (0, saved_errno, _("cannot run command %s"), quote (*cmd));
+
+    exit (exit_status);
+  }
+}