dahdi_cfg: Allow dynamic spans to handle udev based span assignment.

Prior to this commit, if auto_assign_spans was set to 0, it was possible to
get in an endless loop creating and destroying spans. The primary reason was
that all dynamic spans are destroyed and recreated each time dahdi_cfg runs, BUT
dahdi_cfg was run each time a new span showed up in udev when auto_assign_spans
was set to 0.

Now dahdi_cfg will only destroy and recreate dynamic spans if dahdi_cfg is run
without a specifc span number. Also, while creating dynamic spans, dahdi_cfg
will pause for up to one second for the span to be assigned in order to ensure
that the spans are numbered consistently when auto span assignment is
configured.

Signed-off-by: Shaun Ruffell <sruffell@digium.com>
Signed-off-by: Russ Meyerriecks <rmeyerriecks@digium.com>

dahdi_cfg.c

@@ -219,6 +219,19 @@ static bool are_all_spans_assigned(void)
 	return res;
 }
 
+static bool wait_for_all_spans_assigned(unsigned long timeout_sec)
+{
+	bool all_assigned = are_all_spans_assigned();
+	unsigned int timeout = 10*timeout_sec;
+
+	while (!all_assigned && --timeout) {
+		usleep(100000);
+		all_assigned = are_all_spans_assigned();
+	}
+
+	return all_assigned;
+}
+
 static const char *sigtype_to_str(const int sig)
 {
 	switch (sig) {
@@ -1582,15 +1595,9 @@ int main(int argc, char *argv[])
 	}
 
 	if (!restrict_channels && !only_span) {
-		bool all_assigned = are_all_spans_assigned();
+		bool all_assigned = wait_for_all_spans_assigned(5);
-		unsigned int timeout = 4*5; /* We'll wait 5 seconds */
 
-		while (!all_assigned && --timeout) {
+		if (!all_assigned) {
-			usleep(250000);
-			all_assigned = are_all_spans_assigned();
-		}
-
-		if (0 == timeout) {
 			fprintf(stderr,
 				"Timeout waiting for all spans to be assigned.\n");
 		}
@@ -1673,13 +1680,16 @@ finish:
 	if (-1 == sem_wait(lock)) {
 		error("Failed to wait for dahdi_cfg mutex.\n");
 		exit_code = 1;
-		goto release_sem;
+		goto unlink_sem;
 	}
 
+	if (!restrict_channels && !only_span) {
 		for (x=0;x<numdynamic;x++) {
 			/* destroy them all */
 			ioctl(fd, DAHDI_DYNAMIC_DESTROY, &zds[x]);
 		}
+	}
+
 	if (stopmode) {
 		for (x=0;x<spans;x++) {
 			if (only_span && lc[x].span != only_span)
@@ -1704,6 +1714,11 @@ finish:
 			goto release_sem;
 		}
 	}
+
+	if (!restrict_channels && !only_span) {
+
+		sem_post(lock);
+
 		for (x=0;x<numdynamic;x++) {
 			if (ioctl(fd, DAHDI_DYNAMIC_CREATE, &zds[x])) {
 				fprintf(stderr, "DAHDI dynamic span creation failed: %s\n", strerror(errno));
@@ -1711,7 +1726,16 @@ finish:
 				exit_code = 1;
 				goto release_sem;
 			}
+			wait_for_all_spans_assigned(1);
 		}
+
+		if (-1 == sem_wait(lock)) {
+			error("Failed to wait for dahdi_cfg mutex after creating dynamic spans.\n");
+			exit_code = 1;
+			goto unlink_sem;
+		}
+	}
+
 	for (x=1;x<DAHDI_MAX_CHANNELS;x++) {
 		struct dahdi_params current_state;
 		int master;
@@ -1891,9 +1915,11 @@ finish:
 	exit_code = apply_fiftysix();
 
 release_sem:
-	if (SEM_FAILED != lock) {
+	if (SEM_FAILED != lock)
 		sem_post(lock);
+
+unlink_sem:
+	if (SEM_FAILED != lock)
 		sem_unlink(SEM_NAME);
-	}
 	exit(exit_code);
 }