X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=blobdiff_plain;f=src%2Fcore%2Floopback-setup.c;h=aff24fa64295146311a4fe34048a42782b686bea;hp=46c1fc843a56ac8615588cd67efe2a20b349355f;hb=cac914e643a50c72893c5478f6886e0978f8fa18;hpb=08e1fb68d78b4adf26cce8387fc428b9e370bcf4

diff --git a/src/core/loopback-setup.c b/src/core/loopback-setup.c
index 46c1fc843..aff24fa64 100644
--- a/src/core/loopback-setup.c
+++ b/src/core/loopback-setup.c
@@ -61,7 +61,8 @@ static ssize_t sendto_loop(int fd, const void *buf, size_t buf_len, int flags, c
         for (;;) {
                 ssize_t l;
 
-                if ((l = sendto(fd, buf, buf_len, flags, sa, sa_len)) >= 0)
+                l = sendto(fd, buf, buf_len, flags, sa, sa_len);
+                if (l >= 0)
                         return l;
 
                 if (errno != EINTR)
@@ -74,7 +75,8 @@ static ssize_t recvfrom_loop(int fd, void *buf, size_t buf_len, int flags, struc
         for (;;) {
                 ssize_t l;
 
-                if ((l = recvfrom(fd, buf, buf_len, flags, sa, sa_len)) >= 0)
+                l = recvfrom(fd, buf, buf_len, flags, sa, sa_len);
+                if (l >= 0)
                         return l;
 
                 if (errno != EINTR)
@@ -86,25 +88,26 @@ static int add_adresses(int fd, int if_loopback, unsigned *requests) {
         union {
                 struct sockaddr sa;
                 struct sockaddr_nl nl;
-        } sa;
+        } sa = {
+                .nl.nl_family = AF_NETLINK,
+        };
+
         union {
                 struct nlmsghdr header;
                 uint8_t buf[NLMSG_ALIGN(sizeof(struct nlmsghdr)) +
                             NLMSG_ALIGN(sizeof(struct ifaddrmsg)) +
                             RTA_LENGTH(sizeof(struct in6_addr))];
-        } request;
+        } request = {
+                .header.nlmsg_len = NLMSG_LENGTH(sizeof(struct ifaddrmsg)),
+                .header.nlmsg_type = RTM_NEWADDR,
+                .header.nlmsg_flags = NLM_F_REQUEST|NLM_F_CREATE|NLM_F_ACK,
+                .header.nlmsg_seq = *requests + 1,
+        };
 
         struct ifaddrmsg *ifaddrmsg;
         uint32_t ipv4_address = htonl(INADDR_LOOPBACK);
         int r;
 
-        zero(request);
-
-        request.header.nlmsg_len = NLMSG_LENGTH(sizeof(struct ifaddrmsg));
-        request.header.nlmsg_type = RTM_NEWADDR;
-        request.header.nlmsg_flags = NLM_F_REQUEST|NLM_F_CREATE|NLM_F_ACK;
-        request.header.nlmsg_seq = *requests + 1;
-
         ifaddrmsg = NLMSG_DATA(&request.header);
         ifaddrmsg->ifa_family = AF_INET;
         ifaddrmsg->ifa_prefixlen = 8;
@@ -112,12 +115,11 @@ static int add_adresses(int fd, int if_loopback, unsigned *requests) {
         ifaddrmsg->ifa_scope = RT_SCOPE_HOST;
         ifaddrmsg->ifa_index = if_loopback;
 
-        if ((r = add_rtattr(&request.header, sizeof(request), IFA_LOCAL, &ipv4_address, sizeof(ipv4_address))) < 0)
+        r = add_rtattr(&request.header, sizeof(request), IFA_LOCAL,
+                       &ipv4_address, sizeof(ipv4_address));
+        if (r < 0)
                 return r;
 
-        zero(sa);
-        sa.nl.nl_family = AF_NETLINK;
-
         if (sendto_loop(fd, &request, request.header.nlmsg_len, 0, &sa.sa, sizeof(sa)) < 0)
                 return -errno;
         (*requests)++;
@@ -131,7 +133,9 @@ static int add_adresses(int fd, int if_loopback, unsigned *requests) {
         ifaddrmsg->ifa_family = AF_INET6;
         ifaddrmsg->ifa_prefixlen = 128;
 
-        if ((r = add_rtattr(&request.header, sizeof(request), IFA_LOCAL, &in6addr_loopback, sizeof(in6addr_loopback))) < 0)
+        r = add_rtattr(&request.header, sizeof(request), IFA_LOCAL,
+                       &in6addr_loopback, sizeof(in6addr_loopback));
+        if (r < 0)
                 return r;
 
         if (sendto_loop(fd, &request, request.header.nlmsg_len, 0, &sa.sa, sizeof(sa)) < 0)
@@ -145,31 +149,29 @@ static int start_interface(int fd, int if_loopback, unsigned *requests) {
         union {
                 struct sockaddr sa;
                 struct sockaddr_nl nl;
-        } sa;
+        } sa = {
+                .nl.nl_family = AF_NETLINK,
+        };
+
         union {
                 struct nlmsghdr header;
                 uint8_t buf[NLMSG_ALIGN(sizeof(struct nlmsghdr)) +
                             NLMSG_ALIGN(sizeof(struct ifinfomsg))];
-        } request;
+        } request = {
+                .header.nlmsg_len = NLMSG_LENGTH(sizeof(struct ifinfomsg)),
+                .header.nlmsg_type = RTM_NEWLINK,
+                .header.nlmsg_flags = NLM_F_REQUEST|NLM_F_ACK,
+                .header.nlmsg_seq = *requests + 1,
+        };
 
         struct ifinfomsg *ifinfomsg;
 
-        zero(request);
-
-        request.header.nlmsg_len = NLMSG_LENGTH(sizeof(struct ifinfomsg));
-        request.header.nlmsg_type = RTM_NEWLINK;
-        request.header.nlmsg_flags = NLM_F_REQUEST|NLM_F_ACK;
-        request.header.nlmsg_seq = *requests + 1;
-
         ifinfomsg = NLMSG_DATA(&request.header);
         ifinfomsg->ifi_family = AF_UNSPEC;
         ifinfomsg->ifi_index = if_loopback;
         ifinfomsg->ifi_flags = IFF_UP;
         ifinfomsg->ifi_change = IFF_UP;
 
-        zero(sa);
-        sa.nl.nl_family = AF_NETLINK;
-
         if (sendto_loop(fd, &request, request.header.nlmsg_len, 0, &sa.sa, sizeof(sa)) < 0)
                 return -errno;
 
@@ -193,7 +195,8 @@ static int read_response(int fd, unsigned requests_max) {
         socklen_t sa_len = sizeof(sa);
         struct nlmsgerr *nlmsgerr;
 
-        if ((l = recvfrom_loop(fd, &response, sizeof(response), 0, &sa.sa, &sa_len)) < 0)
+        l = recvfrom_loop(fd, &response, sizeof(response), 0, &sa.sa, &sa_len);
+        if (l < 0)
                 return -errno;
 
         if (sa_len != sizeof(sa.nl) ||
@@ -217,58 +220,89 @@ static int read_response(int fd, unsigned requests_max) {
 
         nlmsgerr = NLMSG_DATA(&response.header);
 
-        if (nlmsgerr->error < 0 && nlmsgerr->error != -EEXIST) {
-                log_warning("Netlink failure for request %i: %s", response.header.nlmsg_seq, strerror(-nlmsgerr->error));
+        if (nlmsgerr->error < 0 && nlmsgerr->error != -EEXIST)
                 return nlmsgerr->error;
-        }
 
         return response.header.nlmsg_seq;
 }
 
+static int check_loopback(void) {
+        int r;
+        _cleanup_close_ int fd;
+        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;
+}
+
 int loopback_setup(void) {
         int r, if_loopback;
         union {
                 struct sockaddr sa;
                 struct sockaddr_nl nl;
-                struct sockaddr_storage storage;
-        } sa;
+        } sa = {
+                .nl.nl_family = AF_NETLINK,
+        };
         unsigned requests = 0, i;
-        int fd;
+        _cleanup_close_ int fd = -1;
+        bool eperm = false;
 
         errno = 0;
-        if ((if_loopback = (int) if_nametoindex("lo")) <= 0)
+        if_loopback = (int) if_nametoindex("lo");
+        if (if_loopback <= 0)
                 return errno ? -errno : -ENODEV;
 
-        if ((fd = socket(PF_NETLINK, SOCK_RAW, NETLINK_ROUTE)) < 0)
+        fd = socket(PF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
+        if (fd < 0)
                 return -errno;
 
-        zero(sa);
-        sa.nl.nl_family = AF_NETLINK;
-
         if (bind(fd, &sa.sa, sizeof(sa)) < 0) {
                 r = -errno;
-                goto finish;
+                goto error;
         }
 
-        if ((r = add_adresses(fd, if_loopback, &requests)) < 0)
-                goto finish;
+        r = add_adresses(fd, if_loopback, &requests);
+        if (r < 0)
+                goto error;
 
-        if ((r = start_interface(fd, if_loopback, &requests)) < 0)
-                goto finish;
+        r = start_interface(fd, if_loopback, &requests);
+        if (r < 0)
+                goto error;
 
         for (i = 0; i < requests; i++) {
-                if ((r = read_response(fd, requests)) < 0)
-                        goto finish;
-        }
+                r = read_response(fd, requests);
 
-        r = 0;
+                if (r == -EPERM)
+                        eperm = true;
+                else if (r  < 0)
+                        goto error;
+        }
 
-finish:
-        if (r < 0)
-                log_warning("Failed to configure loopback device: %s", strerror(-r));
+        if (eperm && check_loopback() < 0) {
+                r = -EPERM;
+                goto error;
+        }
 
-        if (fd >= 0)
-                close_nointr_nofail(fd);
+        return 0;
 
+error:
+        log_warning("Failed to configure loopback device: %s", strerror(-r));
         return r;
 }