cgroups: adjust previous commit

[mirror_lxc.git] / src / lxc / cgroup.c

diff --git a/src/lxc/cgroup.c b/src/lxc/cgroup.c
index 87d1bb75cb9173c61b6b2c783637e3acfc62146e..fd6015539b6ed90e54d11c90dd16ead004856bf1 100644 (file)
--- a/src/lxc/cgroup.c
+++ b/src/lxc/cgroup.c
@@ -2026,6 +2026,8 @@ static int handle_cgroup_settings(struct cgroup_mount_point *mp,
        int r, saved_errno = 0;
        char buf[2];
 
+       mp->need_cpuset_init = false;
+
        /* If this is the memory cgroup, we want to enforce hierarchy.
         * But don't fail if for some reason we can't.
         */
@@ -2058,6 +2060,7 @@ static int handle_cgroup_settings(struct cgroup_mount_point *mp,
                 * was created
                 */
                if (stat(cc_path, &sb) != 0 && errno == ENOENT) {
+                       mp->need_cpuset_init = true;
                        free(cc_path);
                        return 0;
                }
@@ -2075,75 +2078,85 @@ static int handle_cgroup_settings(struct cgroup_mount_point *mp,
        return 0;
 }
 
-static bool cgroup_read_from_file(const char *fn, char buf[], size_t bufsize)
+static int cgroup_read_from_file(const char *fn, char buf[], size_t bufsize)
 {
        int ret = lxc_read_from_file(fn, buf, bufsize);
        if (ret < 0) {
                SYSERROR("failed to read %s", fn);
-               return false;
+               return ret;
        }
        if (ret == bufsize) {
-               ERROR("too much data in %s", fn);
-               return false;
+               if (bufsize > 0) {
+                       /* obviously this wasn't empty */
+                       buf[bufsize-1] = '\0';
+                       return ret;
+               }
+               /* Callers don't do this, but regression/sanity check */
+               ERROR("%s: was not expecting 0 bufsize", __func__);
+               return -1;
        }
        buf[ret] = '\0';
-       return true;
+       return ret;
 }
 
 static bool do_init_cpuset_file(struct cgroup_mount_point *mp,
                                const char *path, const char *name)
 {
-       char value[128];
-       char *childfile, *parentfile, *tmp;
-       bool ok;
+       char value[1024];
+       char *childfile, *parentfile = NULL, *tmp;
+       int ret;
+       bool ok = false;
+
+       if (!mp->need_cpuset_init)
+               return true;
 
        childfile = cgroup_to_absolute_path(mp, path, name);
        if (!childfile)
                return false;
 
        /* don't overwrite a non-empty value in the file */
-       if (!cgroup_read_from_file(childfile, value, sizeof(value))) {
-               free(childfile);
-               return false;
-       }
+       ret = cgroup_read_from_file(childfile, value, sizeof(value));
+       if (ret < 0)
+               goto out;
        if (value[0] != '\0' && value[0] != '\n') {
-               free(childfile);
-               return true;
+               ok = true;
+               goto out;
        }
 
        /* path to the same name in the parent cgroup */
        parentfile = strdup(path);
        if (!parentfile)
-               return false;
+               goto out;
+
        tmp = strrchr(parentfile, '/');
-       if (!tmp) {
-               free(childfile);
-               free(parentfile);
-               return false;
-       }
+       if (!tmp)
+               goto out;
        if (tmp == parentfile)
                tmp++; /* keep the '/' at the start */
        *tmp = '\0';
        tmp = parentfile;
        parentfile = cgroup_to_absolute_path(mp, tmp, name);
        free(tmp);
-       if (!parentfile) {
-               free(childfile);
-               return false;
-       }
+       if (!parentfile)
+               goto out;
 
        /* copy from parent to child cgroup */
-       if (!cgroup_read_from_file(parentfile, value, sizeof(value))) {
-               free(parentfile);
-               free(childfile);
-               return false;
+       ret = cgroup_read_from_file(parentfile, value, sizeof(value));
+       if (ret < 0)
+               goto out;
+       if (ret == sizeof(value)) {
+               /* If anyone actually sees this error, we can address it */
+               ERROR("parent cpuset value too long");
+               goto out;
        }
        ok = (lxc_write_to_file(childfile, value, strlen(value), false) >= 0);
+
+out:
        if (!ok)
                SYSERROR("failed writing %s", childfile);
-       free(parentfile);
+       if (parentfile)
+               free(parentfile);
        free(childfile);
-
        return ok;
 }