util: replace close_nointr_nofail() by a more useful safe_close()

safe_close() automatically becomes a NOP when a negative fd is passed,
and returns -1 unconditionally. This makes it easy to write lines like
this:

        fd = safe_close(fd);

Which will close an fd if it is open, and reset the fd variable
correctly.

By making use of this new scheme we can drop a > 200 lines of code that
was required to test for non-negative fds or to reset the closed fd
variable afterwards.

9 files changed, 64 insertions, 89 deletions

diff --git a/src/shared/ask-password-api.c b/src/shared/ask-password-api.c
index a328f145e9..117f0c6687 100644
--- a/src/shared/ask-password-api.c
+++ b/src/shared/ask-password-api.c
@@ -226,8 +226,7 @@ int ask_password_tty(
         r = 0;
 
 finish:
-        if (notify >= 0)
-                close_nointr_nofail(notify);
+        safe_close(notify);
 
         if (ttyfd >= 0) {
 
@@ -236,7 +235,7 @@ finish:
                         tcsetattr(ttyfd, TCSADRAIN, &old_termios);
                 }
 
-                close_nointr_nofail(ttyfd);
+                safe_close(ttyfd);
         }
 
         return r;
@@ -290,7 +289,7 @@ static int create_socket(char **name) {
         return fd;
 
 fail:
-        close_nointr_nofail(fd);
+        safe_close(fd);
 
         return r;
 }
@@ -521,19 +520,15 @@ int ask_password_agent(
         r = 0;
 
 finish:
-        if (fd >= 0)
-                close_nointr_nofail(fd);
+        safe_close(fd);
 
         if (socket_name) {
                 unlink(socket_name);
                 free(socket_name);
         }
 
-        if (socket_fd >= 0)
-                close_nointr_nofail(socket_fd);
-
-        if (signal_fd >= 0)
-                close_nointr_nofail(signal_fd);
+        safe_close(socket_fd);
+        safe_close(signal_fd);
 
         if (f)
                 fclose(f);
diff --git a/src/shared/fdset.c b/src/shared/fdset.c
index fd27398ebb..a2c861de3f 100644
--- a/src/shared/fdset.c
+++ b/src/shared/fdset.c
@@ -82,7 +82,7 @@ int fdset_put_dup(FDSet *s, int fd) {
 
         r = fdset_put(s, copy);
         if (r < 0) {
-                close_nointr_nofail(copy);
+                safe_close(copy);
                 return r;
         }
 
diff --git a/src/shared/install.c b/src/shared/install.c
index f57b94d599..74090463d9 100644
--- a/src/shared/install.c
+++ b/src/shared/install.c
@@ -204,7 +204,7 @@ static int remove_marked_symlinks_fd(
 
         d = fdopendir(fd);
         if (!d) {
-                close_nointr_nofail(fd);
+                safe_close(fd);
                 return -errno;
         }
 
@@ -244,7 +244,7 @@ static int remove_marked_symlinks_fd(
 
                         p = path_make_absolute(de->d_name, path);
                         if (!p) {
-                                close_nointr_nofail(nfd);
+                                safe_close(nfd);
                                 return -ENOMEM;
                         }
 
@@ -344,7 +344,7 @@ static int remove_marked_symlinks(
                         r = q;
         } while (deleted);
 
-        close_nointr_nofail(fd);
+        safe_close(fd);
 
         return r;
 }
@@ -367,7 +367,7 @@ static int find_symlinks_fd(
 
         d = fdopendir(fd);
         if (!d) {
-                close_nointr_nofail(fd);
+                safe_close(fd);
                 return -errno;
         }
 
@@ -403,7 +403,7 @@ static int find_symlinks_fd(
 
                         p = path_make_absolute(de->d_name, path);
                         if (!p) {
-                                close_nointr_nofail(nfd);
+                                safe_close(nfd);
                                 return -ENOMEM;
                         }
 
@@ -1008,7 +1008,7 @@ static int unit_file_load(
 
         f = fdopen(fd, "re");
         if (!f) {
-                close_nointr_nofail(fd);
+                safe_close(fd);
                 return -ENOMEM;
         }
 
diff --git a/src/shared/log.c b/src/shared/log.c
index 5ea1e3a0e8..a4b3b68ef1 100644
--- a/src/shared/log.c
+++ b/src/shared/log.c
@@ -62,7 +62,7 @@ void log_close_console(void) {
 
         if (getpid() == 1) {
                 if (console_fd >= 3)
-                        close_nointr_nofail(console_fd);
+                        safe_close(console_fd);
 
                 console_fd = -1;
         }
@@ -84,12 +84,7 @@ static int log_open_console(void) {
 }
 
 void log_close_kmsg(void) {
-
-        if (kmsg_fd < 0)
-                return;
-
-        close_nointr_nofail(kmsg_fd);
-        kmsg_fd = -1;
+        kmsg_fd = safe_close(kmsg_fd);
 }
 
 static int log_open_kmsg(void) {
@@ -105,12 +100,7 @@ static int log_open_kmsg(void) {
 }
 
 void log_close_syslog(void) {
-
-        if (syslog_fd < 0)
-                return;
-
-        close_nointr_nofail(syslog_fd);
-        syslog_fd = -1;
+        syslog_fd = safe_close(syslog_fd);
 }
 
 static int create_log_socket(int type) {
@@ -152,7 +142,7 @@ static int log_open_syslog(void) {
         }
 
         if (connect(syslog_fd, &sa.sa, offsetof(struct sockaddr_un, sun_path) + strlen(sa.un.sun_path)) < 0) {
-                close_nointr_nofail(syslog_fd);
+                safe_close(syslog_fd);
 
                 /* Some legacy syslog systems still use stream
                  * sockets. They really shouldn't. But what can we
@@ -180,12 +170,7 @@ fail:
 }
 
 void log_close_journal(void) {
-
-        if (journal_fd < 0)
-                return;
-
-        close_nointr_nofail(journal_fd);
-        journal_fd = -1;
+        journal_fd = safe_close(journal_fd);
 }
 
 static int log_open_journal(void) {
diff --git a/src/shared/logs-show.c b/src/shared/logs-show.c
index f7d84fc723..df49375724 100644
--- a/src/shared/logs-show.c
+++ b/src/shared/logs-show.c
@@ -1171,8 +1171,7 @@ static int get_boot_id_for_machine(const char *machine, sd_id128_t *boot_id) {
         if (child == 0) {
                 int fd;
 
-                close_nointr_nofail(pair[0]);
-                pair[0] = -1;
+                pair[0] = safe_close(pair[0]);
 
                 r = namespace_enter(pidnsfd, mntnsfd, rootfd);
                 if (r < 0)
@@ -1183,7 +1182,7 @@ static int get_boot_id_for_machine(const char *machine, sd_id128_t *boot_id) {
                         _exit(EXIT_FAILURE);
 
                 k = loop_read(fd, buf, 36, false);
-                close_nointr_nofail(fd);
+                safe_close(fd);
                 if (k != 36)
                         _exit(EXIT_FAILURE);
 
@@ -1194,8 +1193,7 @@ static int get_boot_id_for_machine(const char *machine, sd_id128_t *boot_id) {
                 _exit(EXIT_SUCCESS);
         }
 
-        close_nointr_nofail(pair[1]);
-        pair[1] = -1;
+        pair[1] = safe_close(pair[1]);
 
         r = wait_for_terminate(child, &si);
         if (r < 0 || si.si_code != CLD_EXITED || si.si_status != EXIT_SUCCESS)
diff --git a/src/shared/spawn-polkit-agent.c b/src/shared/spawn-polkit-agent.c
index f9e52cdcbd..fccf1e9173 100644
--- a/src/shared/spawn-polkit-agent.c
+++ b/src/shared/spawn-polkit-agent.c
@@ -61,7 +61,7 @@ int polkit_agent_open(void) {
                        POLKIT_AGENT_BINARY_PATH, "--notify-fd", notify_fd, "--fallback", NULL);
 
         /* Close the writing side, because that's the one for the agent */
-        close_nointr_nofail(pipe_fd[1]);
+        safe_close(pipe_fd[1]);
 
         if (r < 0)
                 log_error("Failed to fork TTY ask password agent: %s", strerror(-r));
@@ -69,7 +69,7 @@ int polkit_agent_open(void) {
                 /* Wait until the agent closes the fd */
                 fd_wait_for_event(pipe_fd[0], POLLHUP, (usec_t) -1);
 
-        close_nointr_nofail(pipe_fd[0]);
+        safe_close(pipe_fd[0]);
 
         return r;
 }
diff --git a/src/shared/util.c b/src/shared/util.c
index 75870fcbe2..a8c4523905 100644
--- a/src/shared/util.c
+++ b/src/shared/util.c
@@ -183,13 +183,22 @@ int close_nointr(int fd) {
                 return -errno;
 }
 
-void close_nointr_nofail(int fd) {
-        PROTECT_ERRNO;
+int safe_close(int fd) {
+
+        /*
+         * Like close_nointr() but cannot fail. Guarantees errno is
+         * unchanged. Is a NOP with negative fds passed, and returns
+         * -1, so that it can be used in this syntax:
+         *
+         * fd = safe_close(fd);
+         */
 
-        /* like close_nointr() but cannot fail, and guarantees errno
-         * is unchanged */
+        if (fd >= 0) {
+                PROTECT_ERRNO;
+                assert_se(close_nointr(fd) == 0);
+        }
 
-        assert_se(close_nointr(fd) == 0);
+        return -1;
 }
 
 void close_many(const int fds[], unsigned n_fd) {
@@ -198,7 +207,7 @@ void close_many(const int fds[], unsigned n_fd) {
         assert(fds || n_fd <= 0);
 
         for (i = 0; i < n_fd; i++)
-                close_nointr_nofail(fds[i]);
+                safe_close(fds[i]);
 }
 
 int unlink_noerrno(const char *path) {
@@ -1693,16 +1702,13 @@ finish:
 }
 
 int reset_terminal(const char *name) {
-        int fd, r;
+        _cleanup_close_ int fd = -1;
 
         fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC);
         if (fd < 0)
                 return fd;
 
-        r = reset_terminal_fd(fd, true);
-        close_nointr_nofail(fd);
-
-        return r;
+        return reset_terminal_fd(fd, true);
 }
 
 int open_terminal(const char *name, int mode) {
@@ -1741,12 +1747,12 @@ int open_terminal(const char *name, int mode) {
 
         r = isatty(fd);
         if (r < 0) {
-                close_nointr_nofail(fd);
+                safe_close(fd);
                 return -errno;
         }
 
         if (!r) {
-                close_nointr_nofail(fd);
+                safe_close(fd);
                 return -ENOTTY;
         }
 
@@ -1935,11 +1941,10 @@ int acquire_terminal(
                  * ended our handle will be dead. It's important that
                  * we do this after sleeping, so that we don't enter
                  * an endless loop. */
-                close_nointr_nofail(fd);
+                safe_close(fd);
         }
 
-        if (notify >= 0)
-                close_nointr_nofail(notify);
+        safe_close(notify);
 
         r = reset_terminal_fd(fd, true);
         if (r < 0)
@@ -1948,11 +1953,8 @@ int acquire_terminal(
         return fd;
 
 fail:
-        if (fd >= 0)
-                close_nointr_nofail(fd);
-
-        if (notify >= 0)
-                close_nointr_nofail(notify);
+        safe_close(fd);
+        safe_close(notify);
 
         return r;
 }
@@ -2262,7 +2264,7 @@ int make_stdio(int fd) {
         t = dup3(fd, STDERR_FILENO, 0);
 
         if (fd >= 3)
-                close_nointr_nofail(fd);
+                safe_close(fd);
 
         if (r < 0 || s < 0 || t < 0)
                 return -errno;
@@ -2640,7 +2642,7 @@ int rm_rf_children_dangerous(int fd, bool only_dirs, bool honour_sticky, struct
 
         d = fdopendir(fd);
         if (!d) {
-                close_nointr_nofail(fd);
+                safe_close(fd);
 
                 return errno == ENOENT ? 0 : -errno;
         }
@@ -2736,7 +2738,7 @@ int rm_rf_children(int fd, bool only_dirs, bool honour_sticky, struct stat *root
         assert(fd >= 0);
 
         if (fstatfs(fd, &s) < 0) {
-                close_nointr_nofail(fd);
+                safe_close(fd);
                 return -errno;
         }
 
@@ -2745,7 +2747,7 @@ int rm_rf_children(int fd, bool only_dirs, bool honour_sticky, struct stat *root
          * non-state data */
         if (!is_temporary_fs(&s)) {
                 log_error("Attempted to remove disk file system, and we can't allow that.");
-                close_nointr_nofail(fd);
+                safe_close(fd);
                 return -EPERM;
         }
 
@@ -2791,13 +2793,13 @@ static int rm_rf_internal(const char *path, bool only_dirs, bool delete_root, bo
 
         if (!dangerous) {
                 if (fstatfs(fd, &s) < 0) {
-                        close_nointr_nofail(fd);
+                        safe_close(fd);
                         return -errno;
                 }
 
                 if (!is_temporary_fs(&s)) {
                         log_error("Attempted to remove disk file system, and we can't allow that.");
-                        close_nointr_nofail(fd);
+                        safe_close(fd);
                         return -EPERM;
                 }
         }
@@ -3318,7 +3320,7 @@ char *ellipsize(const char *s, size_t length, unsigned percent) {
 }
 
 int touch(const char *path) {
-        int fd;
+        _cleanup_close_ int fd;
 
         assert(path);
 
@@ -3330,7 +3332,6 @@ int touch(const char *path) {
         if (fd < 0)
                 return -errno;
 
-        close_nointr_nofail(fd);
         return 0;
 }
 
@@ -3493,7 +3494,7 @@ DIR *xopendirat(int fd, const char *name, int flags) {
 
         d = fdopendir(nfd);
         if (!d) {
-                close_nointr_nofail(nfd);
+                safe_close(nfd);
                 return NULL;
         }
 
@@ -3987,16 +3988,13 @@ int terminal_vhangup_fd(int fd) {
 }
 
 int terminal_vhangup(const char *name) {
-        int fd, r;
+        _cleanup_close_ int fd;
 
         fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC);
         if (fd < 0)
                 return fd;
 
-        r = terminal_vhangup_fd(fd);
-        close_nointr_nofail(fd);
-
-        return r;
+        return terminal_vhangup_fd(fd);
 }
 
 int vt_disallocate(const char *name) {
@@ -4023,7 +4021,7 @@ int vt_disallocate(const char *name) {
                            "\033[H"    /* move home */
                            "\033[2J",  /* clear screen */
                            10, false);
-                close_nointr_nofail(fd);
+                safe_close(fd);
 
                 return 0;
         }
@@ -4044,7 +4042,7 @@ int vt_disallocate(const char *name) {
                 return fd;
 
         r = ioctl(fd, VT_DISALLOCATE, u);
-        close_nointr_nofail(fd);
+        safe_close(fd);
 
         if (r >= 0)
                 return 0;
@@ -4063,7 +4061,7 @@ int vt_disallocate(const char *name) {
                    "\033[H"   /* move home */
                    "\033[3J", /* clear screen including scrollback, requires Linux 2.6.40 */
                    10, false);
-        close_nointr_nofail(fd);
+        safe_close(fd);
 
         return 0;
 }
@@ -5640,7 +5638,7 @@ int on_ac_power(void) {
                 if (n != 6 || memcmp(contents, "Mains\n", 6))
                         continue;
 
-                close_nointr_nofail(fd);
+                safe_close(fd);
                 fd = openat(device, "online", O_RDONLY|O_CLOEXEC|O_NOCTTY);
                 if (fd < 0) {
                         if (errno == ENOENT)
diff --git a/src/shared/util.h b/src/shared/util.h
index 7752b1e3df..70c20fdcf1 100644
--- a/src/shared/util.h
+++ b/src/shared/util.h
@@ -149,7 +149,8 @@ char *endswith(const char *s, const char *postfix) _pure_;
 bool first_word(const char *s, const char *word) _pure_;
 
 int close_nointr(int fd);
-void close_nointr_nofail(int fd);
+int safe_close(int fd);
+
 void close_many(const int fds[], unsigned n_fd);
 
 int parse_size(const char *t, off_t base, off_t *size);
@@ -620,8 +621,7 @@ static inline void freep(void *p) {
         struct __useless_struct_to_allow_trailing_semicolon__
 
 static inline void closep(int *fd) {
-        if (*fd >= 0)
-                close_nointr_nofail(*fd);
+        safe_close(*fd);
 }
 
 static inline void umaskp(mode_t *u) {
diff --git a/src/shared/watchdog.c b/src/shared/watchdog.c
index ddbe7afd3c..ba9ad9be97 100644
--- a/src/shared/watchdog.c
+++ b/src/shared/watchdog.c
@@ -164,6 +164,5 @@ void watchdog_close(bool disarm) {
                 }
         }
 
-        close_nointr_nofail(watchdog_fd);
-        watchdog_fd = -1;
+        watchdog_fd = safe_close(watchdog_fd);
 }