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-rw-r--r--doc/examples/daemon-depedencies/await-started.c123
1 files changed, 123 insertions, 0 deletions
diff --git a/doc/examples/daemon-depedencies/await-started.c b/doc/examples/daemon-depedencies/await-started.c
new file mode 100644
index 0000000..152f02c
--- /dev/null
+++ b/doc/examples/daemon-depedencies/await-started.c
@@ -0,0 +1,123 @@
+#include <bus.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <unistd.h>
+#include <string.h>
+#include <sys/wait.h>
+
+#define t(stmt) if (stmt) goto fail
+
+
+static char arg[4098];
+static int argc;
+static char **argv;
+static int remaining = 0;
+static char *started = NULL;
+static char msg[BUS_MEMORY_SIZE];
+
+
+static void announce_wait(pid_t pid)
+{
+ bus_t bus;
+ int i;
+ t(bus_open(&bus, getenv("BUS_INIT"), BUS_WRONLY));
+ for (i = 1; i < argc; i++) {
+ if (!started[i]) {
+ sprintf(arg, "%ji awaiting-started %s", (intmax_t)pid, argv[i]);
+ t(bus_write(&bus, arg));
+ }
+ }
+ t(bus_close(&bus));
+ return;
+
+fail:
+ perror("await-started");
+}
+
+
+static int callback(const char *message, void *user_data)
+{
+ int i;
+ char *arg2;
+ char *arg3;
+ pid_t pid;
+ pid_t ppid;
+
+ if (!message) {
+ ppid = getppid();
+ pid = fork();
+ if (pid == 0) {
+ announce_wait(ppid);
+ exit(0);
+ } else {
+ (void) waitpid(pid, NULL, 0); /* Let's pretend everything will go swimmingly. */
+ }
+ return 1;
+ }
+
+ strncpy(msg, message, BUS_MEMORY_SIZE - 1);
+ msg[BUS_MEMORY_SIZE - 1] = 0;
+
+ arg2 = strchr(message, ' ');
+ if (!arg2)
+ return 1;
+ arg3 = strchr(++arg2, ' ');
+ if (!arg3)
+ return 1;
+ *arg3++ = 0;
+
+ if (strcmp(arg2, "started") && strcmp(arg2, "ready"))
+ return 1;
+
+ for (i = 1; i < argc; i++)
+ if (!started[i] && !strcmp(argv[i], arg3))
+ started[i] = 1, remaining--;
+
+ return !!remaining;
+ (void) user_data;
+}
+
+
+int main(int argc_, char *argv_[])
+{
+ bus_t bus;
+ int i;
+
+ argc = argc_;
+ argv = argv_;
+
+ if (argc < 2)
+ return fprintf(stderr, "USAGE: %s daemon...", *argv), 2;
+ t(bus_open(&bus, getenv("BUS_INIT"), BUS_WRONLY));
+ started = calloc(argc - 1, sizeof(char));
+ t(started == NULL);
+
+ started[0] = 1;
+ for (i = 1; i < argc; i++) {
+ sprintf(arg, "grep '^%s$' < \"${XDG_RUNTIME_DIR}/started-daemons\" >/dev/null", argv[i]);
+ if (!WEXITSTATUS(system(arg))) {
+ started[i] = 1;
+ } else {
+ sprintf(arg, "grep '^%s$' < \"${XDG_RUNTIME_DIR}/ready-daemons\" >/dev/null", argv[i]);
+ if (!WEXITSTATUS(system(arg)))
+ started[i] = 1;
+ else
+ remaining++;
+ }
+ }
+
+ if (remaining)
+ bus_read(&bus, callback, NULL);
+
+ bus_close(&bus);
+ free(started);
+ return 0;
+
+fail:
+ perror("await-started");
+ bus_close(&bus);
+ free(started);
+ return 1;
+}
+