apply zhaolei updates

[ltt-control.git] / trunk / ltt-control / liblttctl / liblttctl.c

diff --git a/trunk/ltt-control/liblttctl/liblttctl.c b/trunk/ltt-control/liblttctl/liblttctl.c
index ca5ba08b153717ba6cee872505f5af91a08200b6..e866d73be9758fd37826ecfb7570e2fdea0cadc8 100644 (file)
--- a/trunk/ltt-control/liblttctl/liblttctl.c
+++ b/trunk/ltt-control/liblttctl/liblttctl.c
@@ -39,53 +39,60 @@ static char debugfsmntdir[PATH_MAX];
 
 static int initdebugfsmntdir(void)
 {
-       char mnt_dir[PATH_MAX];
-       char mnt_type[PATH_MAX];
+       return getdebugfsmntdir(debugfsmntdir);
+}
 
-       FILE *fp = fopen("/proc/mounts", "r");
-       if (!fp) {
-               fprintf(stderr, "%s: Can't open /proc/mounts\n", __func__);
-               return 1;
+/*
+ * This function must called posterior to initdebugfsmntdir(),
+ * because it need to use debugfsmntdir[] which is inited in initdebugfsmntdir()
+ */
+static int initmodule(void)
+{
+       char controldirname[PATH_MAX];
+       DIR *dir;
+       int tryload_done = 0;
+
+       sprintf(controldirname, "%s/ltt/control/", debugfsmntdir);
+
+check_again:
+       /*
+        * Check ltt control's debugfs dir
+        *
+        * We don't check is ltt-trace-control module exist, because it maybe
+        * compiled into kernel.
+        */
+       dir = opendir(controldirname);
+       if (dir) {
+               closedir(dir);
+               return 0;
        }
 
-       while (1) {
-               if (fscanf(fp, "%*s %s %s %*s %*s %*s", mnt_dir, mnt_type)
-                       <= 0) {
-                       fprintf(stderr, "%s: debugfs mountpoint not found\n",
-                               __func__);
-                       return 1;
-               }
-               if (!strcmp(mnt_type, "debugfs")) {
-                       strcpy(debugfsmntdir, mnt_dir);
-                       return 0;
-               }
+       if (!tryload_done) {
+               system("modprobe ltt-trace-control");
+               tryload_done = 1;
+               goto check_again;
        }
+
+       return -ENOENT;
 }
 
 int lttctl_init(void)
 {
        int ret;
-       DIR *dir;
-       char controldirname[PATH_MAX];
+
 
        ret = initdebugfsmntdir();
        if (ret) {
-               fprintf(stderr, "Debugfs mount point not found\n");
+               fprintf(stderr, "Get debugfs mount point failed\n");
                return 1;
        }
 
-       /* check ltt control's debugfs dir */
-       sprintf(controldirname, "%s/ltt/control/", debugfsmntdir);
-
-       dir = opendir(controldirname);
-       if (!dir) {
-               fprintf(stderr, "ltt-trace-control's debugfs dir not found\n");
-               closedir(dir);
-               return -errno;
+       ret = initmodule();
+       if (ret) {
+               fprintf(stderr, "Control module seems not work\n");
+               return 1;
        }
 
-       closedir(dir);
-
        return 0;
 }
 
@@ -664,3 +671,33 @@ op_err:
 arg_error:
        return ret;
 }
+
+int getdebugfsmntdir(char *mntdir)
+{
+       char mnt_dir[PATH_MAX];
+       char mnt_type[PATH_MAX];
+       int trymount_done = 0;
+
+       FILE *fp = fopen("/proc/mounts", "r");
+       if (!fp)
+               return -EINVAL;
+
+find_again:
+       while (1) {
+               if (fscanf(fp, "%*s %s %s %*s %*s %*s", mnt_dir, mnt_type) <= 0)
+                       break;
+
+               if (!strcmp(mnt_type, "debugfs")) {
+                       strcpy(mntdir, mnt_dir);
+                       return 0;
+               }
+       }
+
+       if (!trymount_done) {
+               mount("debugfs", "/sys/kernel/debug/", "debugfs", 0, NULL);
+               trymount_done = 1;
+               goto find_again;
+       }
+
+       return -ENOENT;
+}