From 603edc22d0516044b72b09ed94a696edd2de7f37 Mon Sep 17 00:00:00 2001

From: Lennart Poettering <lennart@poettering.net>

Date: Wed, 10 Jun 2015 19:10:47 +0200

Subject: [PATCH] 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.

Cherry-picked from: 2a1288ff89322a2f49c79f6d1832c8164c14a05c

Related: #1318994

---

 src/core/manager.c                      |  2 +-

 src/core/namespace.c                    |  3 +--

 src/import/importd.c                    |  8 ++------

 src/journal/journald-server.c           |  2 +-

 src/libsystemd-network/sd-dhcp-client.c |  2 +-

 src/libsystemd-network/sd-dhcp-server.c |  2 +-

 src/libsystemd/sd-bus/bus-container.c   |  2 +-

 src/libsystemd/sd-bus/bus-socket.c      | 16 ++++++++++------

 src/libsystemd/sd-rtnl/rtnl-message.c   |  2 +-

 src/resolve/resolved-dns-stream.c       |  3 ++-

 src/resolve/resolved-manager.c          |  2 +-

 src/shared/macro.h                      |  3 +++

 src/shared/util.c                       | 12 +++++++++++-

 src/shared/util.h                       |  2 ++

 src/timesync/timesyncd-manager.c        |  2 +-

 15 files changed, 39 insertions(+), 24 deletions(-)

diff --git a/src/core/manager.c b/src/core/manager.c

index c502199..71dd70c 100644

--- a/src/core/manager.c

+++ b/src/core/manager.c

@@ -1679,7 +1679,7 @@ static int manager_dispatch_notify_fd(sd_event_source *source, int fd, uint32_t

                 return -errno;

         }

-        for (cmsg = CMSG_FIRSTHDR(&msghdr); cmsg; cmsg = CMSG_NXTHDR(&msghdr, cmsg)) {

+        CMSG_FOREACH(cmsg, &msghdr) {

                 if (cmsg->cmsg_level == SOL_SOCKET && cmsg->cmsg_type == SCM_RIGHTS) {

                         fd_array = (int*) CMSG_DATA(cmsg);

diff --git a/src/core/namespace.c b/src/core/namespace.c

index ebd5fb3..00495c1 100644

--- a/src/core/namespace.c

+++ b/src/core/namespace.c

@@ -658,12 +658,11 @@ int setup_netns(int netns_storage_socket[2]) {

         } else {

                 /* Yay, found something, so let's join the namespace */

-                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) {

                                 assert(cmsg->cmsg_len == CMSG_LEN(sizeof(int)));

                                 netns = *(int*) CMSG_DATA(cmsg);

                         }

-                }

                 if (setns(netns, CLONE_NEWNET) < 0) {

                         r = -errno;

diff --git a/src/import/importd.c b/src/import/importd.c

index 9aaf991..a29630b 100644

--- a/src/import/importd.c

+++ b/src/import/importd.c

@@ -507,12 +507,8 @@ static int manager_on_notify(sd_event_source *s, int fd, uint32_t revents, void

                 return -errno;

         }

-        for (cmsg = CMSG_FIRSTHDR(&msghdr); cmsg; cmsg = CMSG_NXTHDR(&msghdr, cmsg)) {

-                if (cmsg->cmsg_level == SOL_SOCKET && cmsg->cmsg_type == SCM_RIGHTS) {

-                        close_many((int*) CMSG_DATA(cmsg), (cmsg->cmsg_len - CMSG_LEN(0)) / sizeof(int));

-                        log_warning("Somebody sent us unexpected fds, ignoring.");

-                        return 0;

-                } else if (cmsg->cmsg_level == SOL_SOCKET &&

+        CMSG_FOREACH(cmsg, &msghdr) {

+                if (cmsg->cmsg_level == SOL_SOCKET &&

                            cmsg->cmsg_type == SCM_CREDENTIALS &&

                            cmsg->cmsg_len == CMSG_LEN(sizeof(struct ucred))) {

diff --git a/src/journal/journald-server.c b/src/journal/journald-server.c

index 6a35ebb..1eb1394 100644

--- a/src/journal/journald-server.c

+++ b/src/journal/journald-server.c

@@ -1176,7 +1176,7 @@ int server_process_datagram(sd_event_source *es, int fd, uint32_t revents, void

                         return -errno;

                 }

-                for (cmsg = CMSG_FIRSTHDR(&msghdr); cmsg; cmsg = CMSG_NXTHDR(&msghdr, cmsg)) {

+                CMSG_FOREACH(cmsg, &msghdr) {

                         if (cmsg->cmsg_level == SOL_SOCKET &&

                             cmsg->cmsg_type == SCM_CREDENTIALS &&

diff --git a/src/libsystemd-network/sd-dhcp-client.c b/src/libsystemd-network/sd-dhcp-client.c

index 5f90617..870850e 100644

--- a/src/libsystemd-network/sd-dhcp-client.c

+++ b/src/libsystemd-network/sd-dhcp-client.c

@@ -1590,7 +1590,7 @@ static int client_receive_message_raw(sd_event_source *s, int fd,

         } else if ((size_t)len < sizeof(DHCPPacket))

                 return 0;

-        for (cmsg = CMSG_FIRSTHDR(&msg;; cmsg; cmsg = CMSG_NXTHDR(&msg, cmsg)) {

+        CMSG_FOREACH(cmsg, &msg) {

                 if (cmsg->cmsg_level == SOL_PACKET &&

                     cmsg->cmsg_type == PACKET_AUXDATA &&

                     cmsg->cmsg_len == CMSG_LEN(sizeof(struct tpacket_auxdata))) {

diff --git a/src/libsystemd-network/sd-dhcp-server.c b/src/libsystemd-network/sd-dhcp-server.c

index 0f284eb..c9d0ace 100644

--- a/src/libsystemd-network/sd-dhcp-server.c

+++ b/src/libsystemd-network/sd-dhcp-server.c

@@ -903,7 +903,7 @@ static int server_receive_message(sd_event_source *s, int fd,

         else if ((size_t)len < sizeof(DHCPMessage))

                 return 0;

-        for (cmsg = CMSG_FIRSTHDR(&msg;; cmsg; cmsg = CMSG_NXTHDR(&msg, cmsg)) {

+        CMSG_FOREACH(cmsg, &msg) {

                 if (cmsg->cmsg_level == IPPROTO_IP &&

                     cmsg->cmsg_type == IP_PKTINFO &&

                     cmsg->cmsg_len == CMSG_LEN(sizeof(struct in_pktinfo))) {

diff --git a/src/libsystemd/sd-bus/bus-container.c b/src/libsystemd/sd-bus/bus-container.c

index d29b98a..10ab714 100644

--- a/src/libsystemd/sd-bus/bus-container.c

+++ b/src/libsystemd/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/libsystemd/sd-bus/bus-socket.c b/src/libsystemd/sd-bus/bus-socket.c

index a3c3a45..ab56ef4 100644

--- a/src/libsystemd/sd-bus/bus-socket.c

+++ b/src/libsystemd/sd-bus/bus-socket.c

@@ -503,7 +503,6 @@ 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);

@@ -554,8 +553,10 @@ 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;

@@ -569,6 +570,7 @@ 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)

@@ -930,7 +932,6 @@ 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);

@@ -976,8 +977,10 @@ 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;

@@ -1005,6 +1008,7 @@ 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/libsystemd/sd-rtnl/rtnl-message.c b/src/libsystemd/sd-rtnl/rtnl-message.c

index 9276bbd..cc84253 100644

--- a/src/libsystemd/sd-rtnl/rtnl-message.c

+++ b/src/libsystemd/sd-rtnl/rtnl-message.c

@@ -1444,7 +1444,7 @@ 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/resolve/resolved-dns-stream.c b/src/resolve/resolved-dns-stream.c

index 4c0b557..7f47e72 100644

--- a/src/resolve/resolved-dns-stream.c

+++ b/src/resolve/resolved-dns-stream.c

@@ -113,7 +113,8 @@ static int dns_stream_identify(DnsStream *s) {

         mh.msg_control = &control;

         mh.msg_controllen = sl;

-        for (cmsg = CMSG_FIRSTHDR(&mh); cmsg; cmsg = CMSG_NXTHDR(&mh, cmsg)) {

+

+        CMSG_FOREACH(cmsg, &mh) {

                 if (cmsg->cmsg_level == IPPROTO_IPV6) {

                         assert(s->peer.sa.sa_family == AF_INET6);

diff --git a/src/resolve/resolved-manager.c b/src/resolve/resolved-manager.c

index 7c253aa..173ab8a 100644

--- a/src/resolve/resolved-manager.c

+++ b/src/resolve/resolved-manager.c

@@ -920,7 +920,7 @@ int manager_recv(Manager *m, int fd, DnsProtocol protocol, DnsPacket **ret) {

         } else

                 return -EAFNOSUPPORT;

-        for (cmsg = CMSG_FIRSTHDR(&mh); cmsg; cmsg = CMSG_NXTHDR(&mh, cmsg)) {

+        CMSG_FOREACH(cmsg, &mh) {

                 if (cmsg->cmsg_level == IPPROTO_IPV6) {

                         assert(p->family == AF_INET6);

diff --git a/src/shared/macro.h b/src/shared/macro.h

index 9d857dc..7a57f4e 100644

--- a/src/shared/macro.h

+++ b/src/shared/macro.h

@@ -471,4 +471,7 @@ static inline bool GID_IS_INVALID(gid_t gid) {

         }                                                       \

         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"

diff --git a/src/shared/util.c b/src/shared/util.c

index 4c441a5..357fbfe 100644

--- a/src/shared/util.c

+++ b/src/shared/util.c

@@ -7887,7 +7887,7 @@ int openpt_in_namespace(pid_t pid, int flags) {

         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;

@@ -8375,6 +8375,16 @@ ssize_t string_table_lookup(const char * const *table, size_t len, const char *k

         return -1;

 }

+void cmsg_close_all(struct msghdr *mh) {

+        struct cmsghdr *cmsg;

+

+        assert(mh);

+

+        CMSG_FOREACH(cmsg, mh)

+                if (cmsg->cmsg_level == SOL_SOCKET && cmsg->cmsg_type == SCM_RIGHTS)

+                        close_many((int*) CMSG_DATA(cmsg), (cmsg->cmsg_len - CMSG_LEN(0)) / sizeof(int));

+}

+

 char *shell_maybe_quote(const char *s) {

         const char *p;

         char *r, *t;

diff --git a/src/shared/util.h b/src/shared/util.h

index be04524..12afcc3 100644

--- a/src/shared/util.h

+++ b/src/shared/util.h

@@ -1082,6 +1082,8 @@ void sigkill_wait(pid_t *pid);

 int syslog_parse_priority(const char **p, int *priority, bool with_facility);

+void cmsg_close_all(struct msghdr *mh);

+

 char *shell_maybe_quote(const char *s);

 typedef enum ExtractFlags {

diff --git a/src/timesync/timesyncd-manager.c b/src/timesync/timesyncd-manager.c

index 73ac7ee..5cc1968 100644

--- a/src/timesync/timesyncd-manager.c

+++ b/src/timesync/timesyncd-manager.c

@@ -539,7 +539,7 @@ static int manager_receive_response(sd_event_source *source, int fd, uint32_t re

         }

         recv_time = NULL;

-        for (cmsg = CMSG_FIRSTHDR(&msghdr); cmsg; cmsg = CMSG_NXTHDR(&msghdr, cmsg)) {

+        CMSG_FOREACH(cmsg, &msghdr) {

                 if (cmsg->cmsg_level != SOL_SOCKET)

                         continue;