+
+ int callback (struct dirent *dirent, const char *pathname)
+ {
+ char buf[LINE_MAX];
+ ssize_t buf_len;
+
+ if ((dirent->d_type != DT_DIR && dirent->d_type != DT_LNK)
+ || (dirent->d_type == DT_DIR && strcmp (dirent->d_name, ".") != 0
+ && strcmp (dirent->d_name, "..") != 0)
+ || (dirent->d_type == DT_LNK && strspn (dirent->d_name, "0123456789")
+ != strlen (dirent->d_name)))
+ {
+ fprintf (stderr, "Unexpected entry \"%s\" (d_type %u)"
+ " on readdir (\"%s\"): %m\n",
+ dirent->d_name, (unsigned) dirent->d_type, dirname);
+ return 0;
+ }
+ if (dirent->d_type == DT_DIR)
+ return 0;
+ buf_len = readlink (pathname, buf, sizeof buf - 1);
+ if (buf_len <= 0 || buf_len >= (ssize_t) sizeof buf - 1)
+ {
+ if (errno != ENOENT && errno != EACCES)
+ fprintf (stderr, "Error reading link \"%s\": %m\n", pathname);
+ return 0;
+ }
+ buf[buf_len] = 0;
+ return (*func) (pid, buf);
+ }
+
+ return dir_scan (dirname, callback);
+}
+
+static void pid_fs_scan (void (*func) (pid_t pid, void *data), void *data)
+{
+ int callback (struct dirent *dirent, const char *pathname)
+ {
+ if (dirent->d_type != DT_DIR
+ || strspn (dirent->d_name, "0123456789") != strlen (dirent->d_name))
+ return 0;
+ (*func) (atoi (dirent->d_name), data);
+ return 0;
+ }
+
+ dir_scan ("/proc", callback);