chiark / gitweb /
unit: use weaker dependencies between mount and device units in --user mode
[elogind.git] / src / core / loopback-setup.c
index 7eb28fc..63b15c1 100644 (file)
   along with systemd; If not, see <http://www.gnu.org/licenses/>.
 ***/
 
-#include <errno.h>
-#include <sys/socket.h>
 #include <net/if.h>
-#include <asm/types.h>
-#include <netinet/in.h>
-#include <linux/rtnetlink.h>
-#include <string.h>
 #include <stdlib.h>
-#include <unistd.h>
 
-#include "util.h"
-#include "macro.h"
-#include "loopback-setup.h"
-#include "socket-util.h"
 #include "sd-rtnl.h"
 #include "rtnl-util.h"
+#include "missing.h"
+#include "loopback-setup.h"
 
-static int pipe_handler(sd_rtnl *rtnl, sd_rtnl_message *m, void *userdata) {
-        int *counter = userdata;
-        int r;
-
-        (*counter) --;
-
-        r = sd_rtnl_message_get_errno(m);
-
-        return r == -EEXIST ? 0 : r;
-}
-
-static int add_addresses(sd_rtnl *rtnl, int if_loopback, struct in_addr *ipv4_address, int *counter) {
-        _cleanup_sd_rtnl_message_unref_ sd_rtnl_message *ipv4 = NULL, *ipv6 = NULL;
+static int start_loopback(sd_rtnl *rtnl) {
+        _cleanup_rtnl_message_unref_ sd_rtnl_message *req = NULL;
         int r;
 
-        r = sd_rtnl_message_addr_new(RTM_NEWADDR, if_loopback, AF_INET, 8,
-                                     IFA_F_PERMANENT, RT_SCOPE_HOST, &ipv4);
-        if (r < 0)
-                return r;
-
-        r = sd_rtnl_message_append_in_addr(ipv4, IFA_LOCAL, ipv4_address);
-        if (r < 0)
-                return r;
-
-        r = sd_rtnl_call_async(rtnl, ipv4, &pipe_handler, counter, 0, NULL);
-        if (r < 0)
-                return r;
-
-        (*counter) ++;
-
-        if (!socket_ipv6_is_supported())
-                return 0;
-
-        r = sd_rtnl_message_addr_new(RTM_NEWADDR, if_loopback, AF_INET6, 128,
-                                     IFA_F_PERMANENT, RT_SCOPE_HOST, &ipv6);
+        r = sd_rtnl_message_new_link(rtnl, &req, RTM_SETLINK, LOOPBACK_IFINDEX);
         if (r < 0)
                 return r;
 
-        r = sd_rtnl_message_append_in6_addr(ipv6, IFA_LOCAL, &in6addr_loopback);
+        r = sd_rtnl_message_link_set_flags(req, IFF_UP, IFF_UP);
         if (r < 0)
                 return r;
 
-        r = sd_rtnl_call_async(rtnl, ipv6, &pipe_handler, counter, 0, NULL);
+        r = sd_rtnl_call(rtnl, req, 0, NULL);
         if (r < 0)
                 return r;
 
-        (*counter) ++;
-
         return 0;
 }
 
-static int start_interface(sd_rtnl *rtnl, int if_loopback, struct in_addr *ipv4_address, int *counter) {
-        _cleanup_sd_rtnl_message_unref_ sd_rtnl_message *req = NULL;
+static bool check_loopback(sd_rtnl *rtnl) {
+        _cleanup_rtnl_message_unref_ sd_rtnl_message *req = NULL, *reply = NULL;
+        unsigned flags;
         int r;
 
-        r = sd_rtnl_message_link_new(RTM_SETLINK, if_loopback, &req);
+        r = sd_rtnl_message_new_link(rtnl, &req, RTM_GETLINK, LOOPBACK_IFINDEX);
         if (r < 0)
-                return r;
+                return false;
 
-        r = sd_rtnl_message_link_set_flags(req, IFF_UP, IFF_UP);
+        r = sd_rtnl_call(rtnl, req, 0, &reply);
         if (r < 0)
-                return r;
+                return false;
 
-        r = sd_rtnl_call_async(rtnl, req, &pipe_handler, counter, 0, NULL);
+        r = sd_rtnl_message_link_get_flags(reply, &flags);
         if (r < 0)
-                return r;
+                return false;
 
-        (*counter) ++;
-
-        return 0;
-}
-
-static int check_loopback(void) {
-        int r;
-        _cleanup_close_ int fd = -1;
-        union {
-                struct sockaddr sa;
-                struct sockaddr_in in;
-        } sa = {
-                .in.sin_family = AF_INET,
-                .in.sin_addr.s_addr = INADDR_LOOPBACK,
-        };
-
-        /* If we failed to set up the loop back device, check whether
-         * it might already be set up */
-
-        fd = socket(AF_INET, SOCK_DGRAM|SOCK_NONBLOCK|SOCK_CLOEXEC, 0);
-        if (fd < 0)
-                return -errno;
-
-        if (bind(fd, &sa.sa, sizeof(sa.in)) >= 0)
-                r = 1;
-        else
-                r = errno == EADDRNOTAVAIL ? 0 : -errno;
-
-        return r;
+        return flags & IFF_UP;
 }
 
 int loopback_setup(void) {
-        _cleanup_sd_rtnl_unref_ sd_rtnl *rtnl = NULL;
-        int r, if_loopback, counter = 0;
-        bool eperm = false;
-        struct in_addr ipv4_address;
-
-        errno = 0;
-        if_loopback = (int) if_nametoindex("lo");
-        if (if_loopback <= 0)
-                return errno ? -errno : -ENODEV;
-
-        ipv4_address.s_addr = htonl(INADDR_LOOPBACK);
-
-        r = sd_rtnl_open(0, &rtnl);
-        if (r < 0)
-                return r;
+        _cleanup_rtnl_unref_ sd_rtnl *rtnl = NULL;
+        int r;
 
-        r = add_addresses(rtnl, if_loopback, &ipv4_address, &counter);
+        r = sd_rtnl_open(&rtnl, 0);
         if (r < 0)
                 return r;
 
-        r = start_interface(rtnl, if_loopback, &ipv4_address, &counter);
-        if (r < 0)
-                return r;
+        r = start_loopback(rtnl);
+        if (r < 0) {
 
-        while (counter > 0) {
-                r = sd_rtnl_wait(rtnl, 0);
-                if (r < 0)
-                        return r;
-
-                r = sd_rtnl_process(rtnl, 0);
-                if (r < 0) {
-                        if (r == -EPERM)
-                                eperm = true;
-                        else {
-                                log_warning("Failed to configure loopback device: %s", strerror(-r));
-                                return r;
-                        }
-                }
-        }
+                /* If we lack the permissions to configure the
+                 * loopback device, but we find it to be already
+                 * configured, let's exit cleanly, in order to
+                 * supported unprivileged containers. */
+                if (r == -EPERM && check_loopback(rtnl))
+                        return 0;
 
-        if (eperm && check_loopback() < 0) {
-                log_warning("Failed to configure loopback device: %s", strerror(EPERM));
-                return -EPERM;
+                return log_warning_errno(r, "Failed to configure loopback device: %m");
         }
 
         return 0;