1 files changed, 95 insertions, 0 deletions
diff --git a/src/alarm.c b/src/alarm.c
new file mode 100644
index 0000000..f66af7d
--- /dev/null
+++ b/src/alarm.c
@@ -0,0 +1,95 @@
+/**
+ * alarm — Schedule an alarm for a program when starting it
+ * 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 <unistd.h>
+#include <stdlib.h>
+#include <stddef.h>
+
+
+int main(int argc, char** argv)
+{
+  char** cmdline = NULL;
+  long hours = 0;
+  long minutes = 0;
+  long seconds = 0;
+  long buf = 0;
+  int hms = 0;
+  char* time;
+  
+  if (argc < 3)
+    goto usage;
+  
+  time = argv[1];
+  while (*time)
+    {
+      char c = *time++;
+      if (('0' <= c) && (c <= '9'))
+	buf = buf * 10 - (c & 15);
+      else if (strchr("hms", c))
+	{
+	  if      (c == 'h')  hours   = -buf;
+	  else if (c == 'm')  minutes = -buf;
+	  else if (c == 's')  seconds = -buf;
+	  buf = 0, hms = 1;
+	}
+      else
+	goto usage;
+    }
+  if (!hms)
+    {
+      if (strlen(argv[1]) < 1)
+	return 0;
+      seconds = -buf;
+    }
+  
+  seconds += minutes * 60;
+  seconds += hours * 60 * 60;
+  if ((seconds < 1) || (65535 < seconds))
+    goto usage;
+  
+  cmdline = malloc((size_t)(argc - 1) * sizeof(char*));
+  if (cmdline == NULL)
+    goto fail;
+  memcpy(cmdline, argv + 2, (size_t)(argc - 2) * sizeof(char*));
+  cmdline[argc - 2] = NULL;
+  
+  alarm((unsigned)seconds);
+  execvp(argv[2], cmdline);
+  
+ fail:
+  perror(*argv);
+  free(cmdline);
+  return 1;
+  
+ usage:
+  printf("USAGE: %s <TIME> <COMMAND> <ARGS...>\n", *argv);
+  printf("\n");
+  printf("Recognised patterns for <TIME>:\n");
+  printf("\n");
+  printf("    <SECONDS>[s]\n");
+  printf("    <MINUTES>m[<SECONDS>s]\n");
+  printf("    <HOURS>h[<MINUTES>m][<SECONDS>s]\n");
+  printf("\n");
+  printf("    All values are non-negative integers, and");
+  printf("    the interal must be greater than zero and\n");
+  printf("    at most 18h12m15s.\n");
+  printf("\n");
+  return 1;
+}
+