lxc-user-nic: simplify

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 9026bc425b4d379adf116009a0f836b2997d6c98..0f79451d13293be7d39175b7ea0f743235fc2e4b 100644 (file)
--- a/src/lxc/lxc_user_nic.c
+++ b/src/lxc/lxc_user_nic.c
@@ -61,8 +61,8 @@ static void usage(char *me, bool fail)
 {
        fprintf(stderr, "Usage: %s create {lxcpath} {name} {pid} {type} "
                        "{bridge} {nicname}\n", me);
-       fprintf(stderr, "Usage: %s delete {lxcpath} {name} {pid} {type} "
-                       "{bridge} {nicname}\n", me);
+       fprintf(stderr, "Usage: %s delete {lxcpath} {name} "
+                       "{/proc/<pid>/ns/net} {type} {bridge} {nicname}\n", me);
        fprintf(stderr, "{nicname} is the name to use inside the container\n");
 
        if (fail)
@@ -450,32 +450,26 @@ static char *find_line(char *buf_start, char *buf_end, char *name,
        return NULL;
 }
 
-static int instantiate_veth(char *n1, char **n2)
+static int instantiate_veth(char *veth1, char *veth2)
 {
-       int err;
-
-       err = snprintf(*n2, IFNAMSIZ, "%sp", n1);
-       if (err < 0 || err >= IFNAMSIZ) {
-               usernic_error("%s\n", "Could not create nic name");
-               return -1;
-       }
+       int ret;
 
-       err = lxc_veth_create(n1, *n2);
-       if (err) {
-               usernic_error("Failed to create %s-%s : %s.\n", n1, *n2,
-                             strerror(-err));
+       ret = lxc_veth_create(veth1, veth2);
+       if (ret < 0) {
+               usernic_error("Failed to create %s-%s : %s.\n", veth1, veth2,
+                             strerror(-ret));
                return -1;
        }
 
        /* Changing the high byte of the mac address to 0xfe, the bridge
         * interface will always keep the host's mac address and not take the
         * mac address of a container. */
-       err = setup_private_host_hw_addr(n1);
-       if (err)
+       ret = setup_private_host_hw_addr(veth1);
+       if (ret < 0)
                usernic_error("Failed to change mac address of host interface "
-                             "%s : %s\n", n1, strerror(-err));
+                             "%s : %s\n", veth1, strerror(-ret));
 
-       return netdev_set_flag(n1, IFF_UP);
+       return netdev_set_flag(veth1, IFF_UP);
 }
 
 static int get_mtu(char *name)
@@ -488,28 +482,27 @@ static int get_mtu(char *name)
        return netdev_get_mtu(idx);
 }
 
-static bool create_nic(char *nic, char *br, int pid, char **cnic)
+static int create_nic(char *nic, char *br, int pid, char **cnic)
 {
-       char *veth1buf, *veth2buf;
+       char veth1buf[IFNAMSIZ], veth2buf[IFNAMSIZ];
        int mtu, ret;
 
-       veth1buf = alloca(IFNAMSIZ);
-       veth2buf = alloca(IFNAMSIZ);
-       if (!veth1buf || !veth2buf) {
-               usernic_error("Failed allocate memory: %s\n", strerror(errno));
-               return false;
-       }
-
        ret = snprintf(veth1buf, IFNAMSIZ, "%s", nic);
        if (ret < 0 || ret >= IFNAMSIZ) {
                usernic_error("%s", "Could not create nic name\n");
-               return false;
+               return -1;
        }
 
+       ret = snprintf(veth2buf, IFNAMSIZ, "%sp", veth1buf);
+       if (ret < 0 || ret >= IFNAMSIZ) {
+               usernic_error("%s\n", "Could not create nic name");
+               return -1;
+       }
        /* create the nics */
-       if (instantiate_veth(veth1buf, &veth2buf) < 0) {
+       ret = instantiate_veth(veth1buf, veth2buf);
+       if (ret < 0) {
                usernic_error("%s", "Error creating veth tunnel\n");
-               return false;
+               return -1;
        }
 
        if (strcmp(br, "none")) {
@@ -550,36 +543,14 @@ static bool create_nic(char *nic, char *br, int pid, char **cnic)
        *cnic = strdup(veth2buf);
        if (!*cnic) {
                usernic_error("Failed to copy string \"%s\"\n", veth2buf);
-               return false;
+               return -1;
        }
 
-       return true;
+       return 0;
 
 out_del:
        lxc_netdev_delete_by_name(veth1buf);
-       return false;
-}
-
-/* get_new_nicname() will return the name (vethXXXXXX) which is attached on the
- * host to the lxc bridge. The returned string must be freed by caller.
- */
-static char *get_new_nicname(char *br, int pid, char **cnic)
-{
-       int ret;
-       char nicname[IFNAMSIZ];
-
-       ret = snprintf(nicname, sizeof(nicname), "vethXXXXXX");
-       if (ret < 0 || (size_t)ret >= sizeof(nicname))
-               return NULL;
-
-       if (!lxc_mkifname(nicname))
-               return NULL;
-
-       if (!create_nic(nicname, br, pid, cnic)) {
-               return NULL;
-       }
-
-       return strdup(nicname);
+       return -1;
 }
 
 struct entry_line {
@@ -688,7 +659,8 @@ static char *get_nic_if_avail(int fd, struct alloted_s *names, int pid,
 {
        int ret;
        size_t slen;
-       char *newline, *nicname, *owner;
+       char *newline, *owner;
+       char nicname[IFNAMSIZ];
        struct stat sb;
        struct alloted_s *n;
        int count = 0;
@@ -733,9 +705,16 @@ static char *get_nic_if_avail(int fd, struct alloted_s *names, int pid,
        if (owner == NULL)
                return NULL;
 
-       nicname = get_new_nicname(br, pid, cnic);
-       if (!nicname) {
-               usernic_error("%s", "Failed to get new nic name\n");
+       ret = snprintf(nicname, sizeof(nicname), "vethXXXXXX");
+       if (ret < 0 || (size_t)ret >= sizeof(nicname))
+               return NULL;
+
+       if (!lxc_mkifname(nicname))
+               return NULL;
+
+       ret = create_nic(nicname, br, pid, cnic);
+       if (ret < 0) {
+               usernic_error("%s", "Failed to create new nic\n");
                return NULL;
        }
 
@@ -760,7 +739,6 @@ static char *get_nic_if_avail(int fd, struct alloted_s *names, int pid,
        slen = strlen(owner) + strlen(intype) + strlen(br) + strlen(nicname) + 4;
        newline = malloc(slen + 1);
        if (!newline) {
-               free(nicname);
                free(newline);
                usernic_error("Failed allocate memory: %s\n", strerror(errno));
                return NULL;
@@ -770,7 +748,6 @@ static char *get_nic_if_avail(int fd, struct alloted_s *names, int pid,
        if (ret < 0 || (size_t)ret >= (slen + 1)) {
                if (lxc_netdev_delete_by_name(nicname) != 0)
                        usernic_error("Error unlinking %s\n", nicname);
-               free(nicname);
                free(newline);
                return NULL;
        }
@@ -789,7 +766,6 @@ static char *get_nic_if_avail(int fd, struct alloted_s *names, int pid,
                              strerror(errno));
                if (lxc_netdev_delete_by_name(nicname) != 0)
                        usernic_error("Error unlinking %s\n", nicname);
-               free(nicname);
                free(newline);
                return NULL;
        }
@@ -801,7 +777,7 @@ static char *get_nic_if_avail(int fd, struct alloted_s *names, int pid,
        free(newline);
        lxc_strmunmap(buf, sb.st_size + slen);
 
-       return nicname;
+       return strdup(nicname);
 }
 
 static bool create_db_dir(char *fnam)
@@ -1252,6 +1228,7 @@ int main(int argc, char *argv[])
                free(nicname);
                exit(EXIT_FAILURE);
        }
+
        host_veth_ifidx = if_nametoindex(nicname);
        if (!host_veth_ifidx) {
                free(newname);