--- /dev/null
+/*
+ * Copyright (c) 2009, Erik van der Kouwe
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ * this list of conditions and the following disclaimer.
+ * 2. 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.
+ * 3. 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.
+ */
+
+/*
+ * Functionality implemented according to this specification:
+ * http://www.opengroup.org/onlinepubs/000095399/utilities/nohup.html
+ */
+
+#include <errno.h>
+#include <fcntl.h>
+#include <limits.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+#define NOHUP_OUT_FILENAME "nohup.out"
+
+static void print_usage(const char *argv0)
+{
+ printf("Usage: %s command [arg...]\n", argv0);
+}
+
+static int redirect_tty(void)
+{
+ int fd;
+ char buffer[PATH_MAX + 1], *home;
+
+ /* redirect stdout to a file if needed */
+ if (isatty(STDOUT_FILENO))
+ {
+ /* first try: current directory */
+ fd = open(NOHUP_OUT_FILENAME, O_WRONLY | O_APPEND | O_CREAT, S_IRUSR | S_IWUSR);
+ if (fd < 0)
+ {
+ /* alternative: home directory */
+ home = getenv("HOME");
+ if (home)
+ {
+ snprintf(buffer, sizeof(buffer), "%s/%s", home, NOHUP_OUT_FILENAME);
+ buffer[sizeof(buffer) - 1] = 0;
+ fd = open(buffer, O_WRONLY | O_APPEND | O_CREAT, S_IRUSR | S_IWUSR);
+ }
+ }
+
+ if (fd < 0)
+ {
+ perror("cannot create " NOHUP_OUT_FILENAME " and $HOME/" NOHUP_OUT_FILENAME);
+ return -1;
+ }
+
+ /* move the fd to stdout */
+ if (dup2(fd, STDOUT_FILENO) < 0 || close(fd) < 0)
+ {
+ perror("cannot redirect stdout");
+ return -1;
+ }
+ }
+
+ /* redirect stderr to stdout if needed */
+ if (isatty(STDERR_FILENO))
+ {
+ if (dup2(STDOUT_FILENO, STDERR_FILENO) < 0)
+ {
+ perror("cannot redirect stderr");
+ return -1;
+ }
+ }
+
+ return 0;
+}
+
+int main(int argc, char **argv)
+{
+ struct sigaction sa;
+
+ /* check parameters */
+ if (argc < 2)
+ {
+ print_usage(argv[0]);
+ return 127;
+ }
+
+ /* ignore SIGHUP */
+ sa.sa_handler = SIG_IGN;
+ sigemptyset(&sa.sa_mask);
+ sa.sa_flags = 0;
+ if (sigaction(SIGHUP, &sa, NULL) < 0)
+ {
+ perror("cannot ignore SIGHUP");
+ return 127;
+ }
+
+ /* redirect TTY input and output */
+ if (redirect_tty() < 0)
+ return 127;
+
+ /* run the command */
+ execvp(argv[1], argv + 1);
+ perror("cannot execute");
+
+ /* exit code depends on whether the utility was found */
+ switch (errno)
+ {
+ case ELOOP:
+ case ENAMETOOLONG:
+ case ENOENT:
+ case ENOTDIR:
+ /* utility not found */
+ return 127;
+
+ default:
+ /* exec failed for other reason */
+ return 126;
+ }
+}