sd-daemon: add reference implementation of various daemon apis

[elogind.git] / sd-daemon.c

diff --git a/sd-daemon.c b/sd-daemon.c
new file mode 100644 (file)
index 0000000..cc972da
--- /dev/null
+++ b/sd-daemon.c
@@ -0,0 +1,96 @@
+/*-*- Mode: C; c-basic-offset: 8 -*-*/
+
+/***
+  Copyright 2010 Lennart Poettering
+
+  Permission is hereby granted, free of charge, to any person
+  obtaining a copy of this software and associated documentation files
+  (the "Software"), to deal in the Software without restriction,
+  including without limitation the rights to use, copy, modify, merge,
+  publish, distribute, sublicense, and/or sell copies of the Software,
+  and to permit persons to whom the Software is furnished to do so,
+  subject to the following conditions:
+
+  The above copyright notice and this permission notice shall be
+  included in all copies or substantial portions of the Software.
+
+  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+  MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+  NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+  BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+  ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+  CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+  SOFTWARE.
+***/
+
+#include <stdlib.h>
+#include <errno.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include "sd-daemon.h"
+
+int sd_listen_fds(int unset_environment) {
+
+#ifdef DISABLE_SYSTEMD
+        return 0;
+#else
+        int r;
+        const char *e;
+        char *p = NULL;
+        unsigned long l;
+
+        if (!(e = getenv("LISTEN_PID"))) {
+                r = 0;
+                goto finish;
+        }
+
+        errno = 0;
+        l = strtoul(e, &p, 10);
+
+        if (errno != 0) {
+                r = -errno;
+                goto finish;
+        }
+
+        if (!p || *p || l <= 0) {
+                r = -EINVAL;
+                goto finish;
+        }
+
+        /* Is this for us? */
+        if (getpid() != (pid_t) l) {
+                r = 0;
+                goto finish;
+        }
+
+        if (!(e = getenv("LISTEN_FDS"))) {
+                r = 0;
+                goto finish;
+        }
+
+        errno = 0;
+        l = strtoul(e, &p, 10);
+
+        if (errno != 0) {
+                r = -errno;
+                goto finish;
+        }
+
+        if (!p || *p) {
+                r = -EINVAL;
+                goto finish;
+        }
+
+        r = (int) l;
+
+finish:
+        if (unset_environment) {
+                unsetenv("LISTEN_PID");
+                unsetenv("LISTEN_FDS");
+        }
+
+        return r;
+#endif
+}