afs-supervisor: Add discovery mechanic

Change-Id: Icfcdcc16d0433454c9bb0785d0690f7f173980ae
Signed-off-by: José Bollo <jose.bollo@iot.bzh>

1 files changed, 66 insertions, 0 deletions

diff --git a/src/afs-discover.c b/src/afs-discover.c
new file mode 100644
index 00000000..cad95574
--- /dev/null
+++ b/src/afs-discover.c
@@ -0,0 +1,66 @@
+/*
+ * Copyright (C) 2016, 2017 "IoT.bzh"
+ * Author José Bollo <jose.bollo@iot.bzh>
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#define _GNU_SOURCE
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <stdint.h>
+#include <string.h>
+#include <ctype.h>
+#include <dirent.h>
+#include <unistd.h>
+#include <sys/types.h>
+
+void afs_discover(const char *pattern, void (*callback)(void *closure, pid_t pid), void *closure)
+{
+	intmax_t n;
+	DIR *dir;
+	struct dirent *ent;
+	char *name;
+	char exe[PATH_MAX], lnk[PATH_MAX];
+
+	dir = opendir("/proc");
+	while ((ent = readdir(dir))) {
+		name = ent->d_name;
+		while (isdigit(*name))
+			name++;
+		if (*name)
+			continue;
+		n = snprintf(exe, sizeof exe, "/proc/%s/exe", ent->d_name);
+		if (n < 0 || (size_t)n >= sizeof exe)
+			continue;
+		n = readlink(exe, lnk, sizeof lnk);
+		if (n < 0 || (size_t)n >= sizeof lnk)
+			continue;
+		lnk[n] = 0;
+		name = lnk;
+		while(*name) {
+			while(*name == '/')
+				name++;
+			if (*name) {
+				if (!strcmp(name, pattern)) {
+					callback(closure, (pid_t)atoi(ent->d_name));
+					break;
+				}
+				while(*++name && *name != '/');
+			}
+		}
+	}
+	closedir(dir);
+}
+