add reapd

Signed-off-by: Mattias Andrée <maandree@operamail.com>

1 files changed, 108 insertions, 0 deletions

diff --git a/src/reapd.c b/src/reapd.c
new file mode 100644
index 0000000..5ffecd5
--- /dev/null
+++ b/src/reapd.c
@@ -0,0 +1,108 @@
+/**
+ * orphan-reaper — Place subreapers in your process tree to keep it structured
+ * Copyright © 2014  Mattias Andrée (maandree@member.fsf.org)
+ * 
+ * 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 3 of the License, 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, see <http://www.gnu.org/licenses/>.
+ */
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <errno.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <sys/prctl.h>
+
+
+
+static void usage(void)
+{
+  printf("USAGE: reapd [--fatal] [--] <command...>\n");
+  printf("\n");
+  printf("Unless `--fatal` is used, the program will run <command>\n");
+  printf("even if the process cound not be marked as a child subreaper.\n");
+  printf("\n");
+}
+
+
+int main(int argc, char** argv)
+{
+  int i, j, r, fatal = 0;
+  char** exec_argv;
+  pid_t pid;
+  
+  if ((argc < 2) || !strcmp(argv[1], "--help"))
+    return usage(), argc < 2 ? 1 : 0;
+  
+  for (i = 1; i < argc; i++)
+    if (!strcmp(argv[i], "--fatal"))
+      fatal = 1;
+    else if (!strcmp(argv[i], "--"))
+      {
+	i++;
+	break;
+      }
+    else if (strstr(argv[i], "-") == argv[i])
+      return usage(), 1;
+    else
+      break;
+  
+  if (i == argc)
+    return usage(), 1;
+  
+  exec_argv = malloc((argc - i + 1) * sizeof(char*));
+  if (exec_argv == NULL)
+    return perror(*argv), 2;
+  exec_argv[argc - i] = NULL;
+  for (j = 0; i < argc; j++, i++)
+    exec_argv[j] = argv[i];
+  
+  r = prctl(PR_SET_CHILD_SUBREAPER, 1);
+  if (r < 0)
+    goto error;
+  
+  pid = fork();
+  if (pid == -1)
+    goto error;
+  
+  if (pid == 0)
+    goto exec;
+  else
+    {
+      free(exec_argv);
+      for (;;)
+	if (pid = wait(NULL), pid == -1)
+	  {
+	    if (errno == ECHILD)
+	      return 0;
+	    else if (errno != EINTR)
+	      return perror(*argv), 2;
+	  }
+    }
+  
+ exec:
+  (void) prctl(PR_SET_CHILD_SUBREAPER, 0);
+  execvp(*exec_argv, exec_argv);
+  perror(*argv);
+ fail:
+  free(exec_argv);
+  return 2;
+  
+ error:
+  perror(*argv);
+  if (fatal)
+    goto fail;
+  goto exec;
+}
+