util: introduce CMSG_FOREACH() macro and make use of it everywhere

It's only marginally shorter then the usual for() loop, but certainly
more readable.

diff --git a/src/libelogind/sd-bus/bus-container.c b/src/libelogind/sd-bus/bus-container.c
index f157c25bbab83cfa9c3a37b7307bfb7ced80c9ae..fa7a207448806f8e5cc3e5efd2a3a5217d05a7e3 100644 (file)
--- a/src/libelogind/sd-bus/bus-container.c
+++ b/src/libelogind/sd-bus/bus-container.c
@@ -222,7 +222,7 @@ int bus_container_connect_kernel(sd_bus *b) {
         if (recvmsg(pair[0], &mh, MSG_NOSIGNAL|MSG_CMSG_CLOEXEC) < 0)
                 return -errno;
 
-        for (cmsg = CMSG_FIRSTHDR(&mh); cmsg; cmsg = CMSG_NXTHDR(&mh, cmsg))
+        CMSG_FOREACH(cmsg, &mh)
                 if (cmsg->cmsg_level == SOL_SOCKET && cmsg->cmsg_type == SCM_RIGHTS) {
                         int *fds;
                         unsigned n_fds;

diff --git a/src/libelogind/sd-bus/bus-socket.c b/src/libelogind/sd-bus/bus-socket.c
index 9f3756f0c2628b1ea961a0484d06e59afc21f015..322d57ddbba43437348b713b36a72454d3081591 100644 (file)
--- a/src/libelogind/sd-bus/bus-socket.c
+++ b/src/libelogind/sd-bus/bus-socket.c
@@ -502,7 +502,6 @@ static int bus_socket_read_auth(sd_bus *b) {
                 struct cmsghdr cmsghdr;
                 uint8_t buf[CMSG_SPACE(sizeof(int) * BUS_FDS_MAX)];
         } control;
-        struct cmsghdr *cmsg;
         bool handle_cmsg = false;
 
         assert(b);
@@ -552,8 +551,10 @@ static int bus_socket_read_auth(sd_bus *b) {
 
         b->rbuffer_size += k;
 
-        if (handle_cmsg)
-                for (cmsg = CMSG_FIRSTHDR(&mh); cmsg; cmsg = CMSG_NXTHDR(&mh, cmsg))
+        if (handle_cmsg) {
+                struct cmsghdr *cmsg;
+
+                CMSG_FOREACH(cmsg, &mh)
                         if (cmsg->cmsg_level == SOL_SOCKET &&
                             cmsg->cmsg_type == SCM_RIGHTS) {
                                 int j;
@@ -567,6 +568,7 @@ static int bus_socket_read_auth(sd_bus *b) {
                         } else
                                 log_debug("Got unexpected auxiliary data with level=%d and type=%d",
                                           cmsg->cmsg_level, cmsg->cmsg_type);
+        }
 
         r = bus_socket_auth_verify(b);
         if (r != 0)
@@ -916,7 +918,6 @@ int bus_socket_read_message(sd_bus *bus) {
                 struct cmsghdr cmsghdr;
                 uint8_t buf[CMSG_SPACE(sizeof(int) * BUS_FDS_MAX)];
         } control;
-        struct cmsghdr *cmsg;
         bool handle_cmsg = false;
 
         assert(bus);
@@ -961,8 +962,10 @@ int bus_socket_read_message(sd_bus *bus) {
 
         bus->rbuffer_size += k;
 
-        if (handle_cmsg)
-                for (cmsg = CMSG_FIRSTHDR(&mh); cmsg; cmsg = CMSG_NXTHDR(&mh, cmsg))
+        if (handle_cmsg) {
+                struct cmsghdr *cmsg;
+
+                CMSG_FOREACH(cmsg, &mh)
                         if (cmsg->cmsg_level == SOL_SOCKET &&
                             cmsg->cmsg_type == SCM_RIGHTS) {
                                 int n, *f;
@@ -990,6 +993,7 @@ int bus_socket_read_message(sd_bus *bus) {
                         } else
                                 log_debug("Got unexpected auxiliary data with level=%d and type=%d",
                                           cmsg->cmsg_level, cmsg->cmsg_type);
+        }
 
         r = bus_socket_read_message_need(bus, &need);
         if (r < 0)

diff --git a/src/libelogind/sd-rtnl/rtnl-message.c b/src/libelogind/sd-rtnl/rtnl-message.c
index bab2a4ff08d7e589bd33ece935c66c6a6266aa7a..9dcf7df55972fbc09a01927ca366f357960c96d9 100644 (file)
--- a/src/libelogind/sd-rtnl/rtnl-message.c
+++ b/src/libelogind/sd-rtnl/rtnl-message.c
@@ -1442,7 +1442,7 @@ static int socket_recv_message(int fd, struct iovec *iov, uint32_t *_group, bool
                 return (errno == EAGAIN || errno == EINTR) ? 0 : -errno;
         }
 
-        for (cmsg = CMSG_FIRSTHDR(&msg); cmsg; cmsg = CMSG_NXTHDR(&msg, cmsg)) {
+        CMSG_FOREACH(cmsg, &msg) {
                 if (cmsg->cmsg_level == SOL_SOCKET &&
                     cmsg->cmsg_type == SCM_CREDENTIALS &&
                     cmsg->cmsg_len == CMSG_LEN(sizeof(struct ucred))) {

diff --git a/src/shared/macro.h b/src/shared/macro.h
index 7ae1ed80b6d0d9658672e3bc58d0f6084ad1d7f7..cc1c9e73c08bddcbe39ebee5ac221a14b6d547f1 100644 (file)
--- a/src/shared/macro.h
+++ b/src/shared/macro.h
@@ -467,4 +467,7 @@ do {                                                                    \
         }                                                       \
         struct __useless_struct_to_allow_trailing_semicolon__
 
+#define CMSG_FOREACH(cmsg, mh)                                          \
+        for ((cmsg) = CMSG_FIRSTHDR(mh); (cmsg); (cmsg) = CMSG_NXTHDR((mh), (cmsg)))
+
 #include "log.h"