Provide the fuse options we want ourselves

continue to allow the options which in the past we basically required
callers to provide ("-s -f -o allow_other"), exit on anything else.

Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>

diff --git a/lxcfs.c b/lxcfs.c
index 15adbaa19bd053913a0f6967a023e8bb57065953..020492d06c2961293690059f06203732690b0513 100644 (file)
--- a/lxcfs.c
+++ b/lxcfs.c
@@ -6,10 +6,6 @@
  * See COPYING file for details.
  */
 
-/*
- * NOTES - make sure to run this as -s to avoid threading.
- * TODO - can we enforce that here from the code?
- */
 #define FUSE_USE_VERSION 26
 
 #include <stdio.h>
@@ -2564,7 +2560,8 @@ static void usage(const char *me)
 {
        fprintf(stderr, "Usage:\n");
        fprintf(stderr, "\n");
-       fprintf(stderr, "%s [FUSE and mount options] mountpoint\n", me);
+       fprintf(stderr, "%s mountpoint\n", me);
+       fprintf(stderr, "%s -h\n", me);
        exit(1);
 }
 
@@ -2578,17 +2575,70 @@ static bool is_help(char *w)
        return false;
 }
 
+void swallow_arg(int *argcp, char *argv[], char *which)
+{
+       int i;
+
+       for (i = 1; argv[i]; i++) {
+               if (strcmp(argv[i], which) != 0)
+                       continue;
+               for (; argv[i]; i++) {
+                       argv[i] = argv[i+1];
+               }
+               (*argcp)--;
+               return;
+       }
+}
+
+void swallow_option(int *argcp, char *argv[], char *opt, char *v)
+{
+       int i;
+
+       for (i = 1; argv[i]; i++) {
+               if (!argv[i+1])
+                       continue;
+               if (strcmp(argv[i], opt) != 0)
+                       continue;
+               if (strcmp(argv[i+1], v) != 0) {
+                       fprintf(stderr, "Warning: unexpected fuse option %s\n", v);
+                       exit(1);
+               }
+               for (; argv[i+1]; i++) {
+                       argv[i] = argv[i+2];
+               }
+               (*argcp) -= 2;
+               return;
+       }
+}
+
 int main(int argc, char *argv[])
 {
        int ret;
        struct lxcfs_state *d;
+       /*
+        * what we pass to fuse_main is:
+        * argv[0] -s -f -o allow_other,directio argv[1] NULL
+        */
+#define NARGS 7
+       char *newargv[7];
 
-       if (argc < 2 || is_help(argv[1]))
+       /* accomodate older init scripts */
+       swallow_arg(&argc, argv, "-s");
+       swallow_arg(&argc, argv, "-f");
+       swallow_option(&argc, argv, "-o", "allow_other");
+
+       if (argc != 2 || is_help(argv[1]))
                usage(argv[0]);
 
-       d = malloc(sizeof(*d));
-       if (!d)
-               return -1;
+       d = NIH_MUST( malloc(sizeof(*d)) );
+
+       newargv[0] = argv[0];
+       newargv[1] = "-s";
+       newargv[2] = "-f";
+       newargv[3] = "-o";
+       newargv[4] = "allow_other";
+       newargv[5] = argv[1];
+       newargv[6] = NULL;
 
        if (!cgm_escape_cgroup())
                fprintf(stderr, "WARNING: failed to escape to root cgroup\n");
@@ -2596,7 +2646,7 @@ int main(int argc, char *argv[])
        if (!cgm_get_controllers(&d->subsystems))
                return -1;
 
-       ret = fuse_main(argc, argv, &lxcfs_ops, d);
+       ret = fuse_main(NARGS - 1, newargv, &lxcfs_ops, d);
 
        return ret;
 }