ipc.c: Use ftok() instead of SuperFastHash.
[dss.git] / sig.c
diff --git a/sig.c b/sig.c
index d2d7e3b..99d3dd3 100644 (file)
--- a/sig.c
+++ b/sig.c
@@ -64,12 +64,27 @@ err_out:
        exit(EXIT_FAILURE);
 }
 
-/*
- * just write one integer to signal pipe
- */
+/* Write the signal number to the signal pipe, abort on errors. */
 static void generic_signal_handler(int s)
 {
-       write(signal_pipe[1], &s, sizeof(int));
+       /*
+        * Signal handlers that make system calls must save a copy of errno on
+        * entry to the handler and restore it on exit, to prevent the
+        * possibility of overwriting a errno value that had previously been
+        * set in the main program.
+        */
+       int save_errno = errno;
+       ssize_t ret = write(signal_pipe[1], &s, sizeof(int));
+
+       if (ret == sizeof(int)) {
+               errno = save_errno;
+               return;
+       }
+       if (ret < 0)
+               DSS_EMERG_LOG(("%s\n", strerror(errno)));
+       else
+               DSS_EMERG_LOG(("short write to signal pipe\n"));
+       exit(EXIT_FAILURE);
 }
 
 /**