Copy and use fd_nonblock and RET_NERRNO from systemd source.

Author: someguy

src/netlog/netlog-network.c

@@ -220,7 +220,7 @@ int manager_open_network_socket(Manager *m) {
                         return r;
         }
 
-        r = fd_status_flag(m->socket, O_NONBLOCK, 1);
+        r = fd_nonblock(m->socket, 1);
         if (r < 0)
                 goto fail;
 

src/share/fd-util.c

@@ -121,7 +121,7 @@ int fd_cloexec(int fd, bool cloexec) {
         return 0;
 }
 
-int fd_status_flag(int fd, int flag, bool new_value) {
+int fd_nonblock(int fd, bool nonblock) {
         int flags, nflags;
 
         assert(fd >= 0);
@@ -130,18 +130,11 @@ int fd_status_flag(int fd, int flag, bool new_value) {
         if (flags < 0)
                 return -errno;
 
-        if (new_value)
-                nflags = flags | flag;
-        else
-                nflags = flags & ~flag;
-
+        nflags = UPDATE_FLAG(flags, O_NONBLOCK, nonblock);
         if (nflags == flags)
                 return 0;
 
-        if (fcntl(fd, F_SETFL, nflags) < 0)
-                return -errno;
-
-        return 0;
+        return RET_NERRNO(fcntl(fd, F_SETFL, nflags));
 }
 
 void stdio_unset_cloexec(void) {

src/share/fd-util.h

@@ -38,7 +38,7 @@ DEFINE_TRIVIAL_CLEANUP_FUNC(DIR*, closedir);
 #define _cleanup_close_pair_ _cleanup_(close_pairp)
 
 int fd_cloexec(int fd, bool cloexec);
-int fd_status_flag(int fd, int flag, bool new_value);
+int fd_nonblock(int fd, bool nonblock);
 void stdio_unset_cloexec(void);
 
 

src/share/macro.h

@@ -312,8 +312,12 @@ static inline unsigned long ALIGN_POWER2(unsigned long u) {
                 ans;                                    \
         })
 
+#define UPDATE_FLAG(orig, flag, b)                      \
+        ((b) ? ((orig) | (flag)) : ((orig) & ~(flag)))
 #define SET_FLAG(v, flag, b) \
-        (v) = (b) ? ((v) | (flag)) : ((v) & ~(flag))
+        (v) = UPDATE_FLAG(v, flag, b)
+#define FLAGS_SET(v, flags) \
+        ((~(v) & (flags)) == 0)
 
 #define CASE_F(X) case X:
 #define CASE_F_1(CASE, X) CASE_F(X)

src/share/util.h

@@ -103,6 +103,29 @@ static inline int negative_errno(void) {
         return -errno;
 }
 
+static inline int RET_NERRNO(int ret) {
+
+        /* Helper to wrap system calls in to make them return negative errno errors. This brings system call
+         * error handling in sync with how we usually handle errors in our own code, i.e. with immediate
+         * returning of negative errno. Usage is like this:
+         *
+         *     …
+         *     r = RET_NERRNO(unlink(t));
+         *     …
+         *
+         * or
+         *
+         *     …
+         *     fd = RET_NERRNO(open("/etc/fstab", O_RDONLY|O_CLOEXEC));
+         *     …
+         */
+
+        if (ret < 0)
+                return negative_errno();
+
+        return ret;
+}
+
 static inline unsigned u64log2(uint64_t n) {
 #if __SIZEOF_LONG_LONG__ == 8
         return (n > 1) ? (unsigned) __builtin_clzll(n) ^ 63U : 0;