lxc-user-nic: keep lines from other {users,links}

Assume the db contained the following entries:

    chb veth lxcbr0 veth1
    chb veth lxcbr0 veth2
    chb veth lxdbr0 veth3
    chb veth lxdbr0 veth2
    didi veth lxcbr0 veth4

And you request

    cull_entries("chb", "veth", "lxdbr0", "veth3");

lxc-user-nic would wipe any entries that did not match irrespective of whether
they existed or not. Let's fix that.

Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

diff --git a/src/lxc/lxc_user_nic.c b/src/lxc/lxc_user_nic.c
index 39c7daabffad611851b20f402dfc6d5d3de7c4b9..c4388a74135593ce362dfaf50f25219c209f3b8e 100644 (file)
--- a/src/lxc/lxc_user_nic.c
+++ b/src/lxc/lxc_user_nic.c
@@ -370,27 +370,24 @@ static char *find_line(char *p, char *e, char *u, char *t, char *l)
                        p++;
 
                p2 = get_eow(p, e);
-               if (!p2 || ((size_t)(p2 - p)) != strlen(u) ||
-                   strncmp(p, u, strlen(u)))
-                       goto next;
+               if (!p2 || ((size_t)(p2 - p)) != strlen(u) || strncmp(p, u, strlen(u)))
+                       return ret;
 
                p = p2 + 1;
                while ((p < e) && isblank(*p))
                        p++;
 
                p2 = get_eow(p, e);
-               if (!p2 || ((size_t)(p2 - p)) != strlen(t) ||
-                   strncmp(p, t, strlen(t)))
-                       goto next;
+               if (!p2 || ((size_t)(p2 - p)) != strlen(t) || strncmp(p, t, strlen(t)))
+                       return ret;
 
                p = p2 + 1;
                while ((p < e) && isblank(*p))
                        p++;
 
                p2 = get_eow(p, e);
-               if (!p2 || ((size_t)(p2 - p)) != strlen(l) ||
-                   strncmp(p, l, strlen(l)))
-                       goto next;
+               if (!p2 || ((size_t)(p2 - p)) != strlen(l) || strncmp(p, l, strlen(l)))
+                       return ret;
 
                return ret;
        next:
@@ -410,7 +407,7 @@ static bool nic_exists(char *nic)
                return true;
 
        ret = snprintf(path, MAXPATHLEN, "/sys/class/net/%s", nic);
-       if (ret < 0 || ret >= MAXPATHLEN)
+       if (ret < 0 || (size_t)ret >= MAXPATHLEN)
                return false;
 
        ret = stat(path, &sb);
@@ -562,8 +559,10 @@ static bool get_nic_from_line(char *p, char **nic)
 
        ret = sscanf(p, "%99[^ \t\n] %99[^ \t\n] %99[^ \t\n] %99[^ \t\n]", user,
                     type, br, *nic);
-       if (ret != 4)
+       if (ret != 4) {
+               *nic[0] = '\0';
                return false;
+       }
 
        return true;
 }
@@ -609,6 +608,7 @@ static bool cull_entries(int fd, char *me, char *t, char *br, char *nicname,
        e = buf + len;
        while ((p = find_line(p, e, me, t, br))) {
                struct entry_line *newe;
+               bool exists = false;
 
                newe = realloc(entry_lines, sizeof(*entry_lines) * (n + 1));
                if (!newe) {
@@ -624,10 +624,13 @@ static bool cull_entries(int fd, char *me, char *t, char *br, char *nicname,
                if (!get_nic_from_line(p, &nic))
                        continue;
 
-               if (nic && !nic_exists(nic))
+               if (nic[0] != '\0')
+                       exists = nic_exists(nic);
+
+               if (!exists)
                        entry_lines[n - 1].keep = false;
 
-               if (nicname)
+               if (exists && nicname)
                        if (!strcmp(nic, nicname))
                                *found_nicname = true;
 
@@ -1206,8 +1209,8 @@ int main(int argc, char *argv[])
                free_alloted(&alloted);
 
                if (!found_nicname) {
-                       usernic_error("%s", "Caller is not allowed to delete "
-                                     "network device\n");
+                       usernic_error("Caller is not allowed to delete network "
+                                     "device \"%s\"\n", args.veth_name);
                        exit(EXIT_FAILURE);
                }