util: add a bit of syntactic sugar to run short code fragments with a different umask

6 files changed, 75 insertions, 71 deletions

diff --git a/src/core/machine-id-setup.c b/src/core/machine-id-setup.c
index 51074fea44..fbba3aab78 100644
--- a/src/core/machine-id-setup.c
+++ b/src/core/machine-id-setup.c
@@ -155,31 +155,27 @@ int machine_id_setup(void) {
         bool writable;
         struct stat st;
         char id[34]; /* 32 + \n + \0 */
-        mode_t m;
 
-        m = umask(0000);
-
-        /* We create this 0444, to indicate that this isn't really
-         * something you should ever modify. Of course, since the file
-         * will be owned by root it doesn't matter much, but maybe
-         * people look. */
+        RUN_WITH_UMASK(0000) {
+                /* We create this 0444, to indicate that this isn't really
+                 * something you should ever modify. Of course, since the file
+                 * will be owned by root it doesn't matter much, but maybe
+                 * people look. */
+
+                fd = open("/etc/machine-id", O_RDWR|O_CREAT|O_CLOEXEC|O_NOCTTY, 0444);
+                if (fd >= 0)
+                        writable = true;
+                else {
+                        fd = open("/etc/machine-id", O_RDONLY|O_CLOEXEC|O_NOCTTY);
+                        if (fd < 0) {
+                                log_error("Cannot open /etc/machine-id: %m");
+                                return -errno;
+                        }
 
-        fd = open("/etc/machine-id", O_RDWR|O_CREAT|O_CLOEXEC|O_NOCTTY, 0444);
-        if (fd >= 0)
-                writable = true;
-        else {
-                fd = open("/etc/machine-id", O_RDONLY|O_CLOEXEC|O_NOCTTY);
-                if (fd < 0) {
-                        umask(m);
-                        log_error("Cannot open /etc/machine-id: %m");
-                        return -errno;
+                        writable = false;
                 }
-
-                writable = false;
         }
 
-        umask(m);
-
         if (fstat(fd, &st) < 0) {
                 log_error("fstat() failed: %m");
                 r = -errno;
@@ -215,10 +211,9 @@ int machine_id_setup(void) {
         /* Hmm, we couldn't write it? So let's write it to
          * /run/machine-id as a replacement */
 
-        m = umask(0022);
-        r = write_string_file("/run/machine-id", id);
-        umask(m);
-
+        RUN_WITH_UMASK(0022) {
+                r = write_string_file("/run/machine-id", id);
+        }
         if (r < 0) {
                 log_error("Cannot write /run/machine-id: %s", strerror(-r));
 
diff --git a/src/core/manager.c b/src/core/manager.c
index f90ccd5b5f..e26522a4dd 100644
--- a/src/core/manager.c
+++ b/src/core/manager.c
@@ -1984,7 +1984,6 @@ void manager_dispatch_bus_query_pid_done(
 
 int manager_open_serialization(Manager *m, FILE **_f) {
         char *path = NULL;
-        mode_t saved_umask;
         int fd;
         FILE *f;
 
@@ -1998,9 +1997,9 @@ int manager_open_serialization(Manager *m, FILE **_f) {
         if (!path)
                 return -ENOMEM;
 
-        saved_umask = umask(0077);
-        fd = mkostemp(path, O_RDWR|O_CLOEXEC);
-        umask(saved_umask);
+        RUN_WITH_UMASK(0077) {
+                fd = mkostemp(path, O_RDWR|O_CLOEXEC);
+        }
 
         if (fd < 0) {
                 free(path);
@@ -2515,7 +2514,6 @@ void manager_run_generators(Manager *m) {
         DIR *d = NULL;
         const char *generator_path;
         const char *argv[5];
-        mode_t u;
         int r;
 
         assert(m);
@@ -2549,9 +2547,9 @@ void manager_run_generators(Manager *m) {
         argv[3] = m->generator_unit_path_late;
         argv[4] = NULL;
 
-        u = umask(0022);
-        execute_directory(generator_path, d, (char**) argv);
-        umask(u);
+        RUN_WITH_UMASK(0022) {
+                execute_directory(generator_path, d, (char**) argv);
+        }
 
         trim_generator_dir(m, &m->generator_unit_path);
         trim_generator_dir(m, &m->generator_unit_path_early);
diff --git a/src/shared/ask-password-api.c b/src/shared/ask-password-api.c
index 85530660dc..277efd302e 100644
--- a/src/shared/ask-password-api.c
+++ b/src/shared/ask-password-api.c
@@ -251,7 +251,6 @@ static int create_socket(char **name) {
         } sa;
         int one = 1, r;
         char *c;
-        mode_t u;
 
         assert(name);
 
@@ -265,9 +264,9 @@ static int create_socket(char **name) {
         sa.un.sun_family = AF_UNIX;
         snprintf(sa.un.sun_path, sizeof(sa.un.sun_path)-1, "/run/systemd/ask-password/sck.%llu", random_ull());
 
-        u = umask(0177);
-        r = bind(fd, &sa.sa, offsetof(struct sockaddr_un, sun_path) + strlen(sa.un.sun_path));
-        umask(u);
+        RUN_WITH_UMASK(0177) {
+                r = bind(fd, &sa.sa, offsetof(struct sockaddr_un, sun_path) + strlen(sa.un.sun_path));
+        }
 
         if (r < 0) {
                 r = -errno;
@@ -317,7 +316,6 @@ int ask_password_agent(
         int socket_fd = -1, signal_fd = -1;
         sigset_t mask, oldmask;
         struct pollfd pollfd[_FD_MAX];
-        mode_t u;
 
         assert(_passphrases);
 
@@ -327,9 +325,9 @@ int ask_password_agent(
 
         mkdir_p_label("/run/systemd/ask-password", 0755);
 
-        u = umask(0022);
-        fd = mkostemp(temp, O_CLOEXEC|O_CREAT|O_WRONLY);
-        umask(u);
+        RUN_WITH_UMASK(0022) {
+                fd = mkostemp(temp, O_CLOEXEC|O_CREAT|O_WRONLY);
+        }
 
         if (fd < 0) {
                 log_error("Failed to create password file: %m");
diff --git a/src/shared/util.c b/src/shared/util.c
index d861ca9f09..1bffd84d1f 100644
--- a/src/shared/util.c
+++ b/src/shared/util.c
@@ -5732,12 +5732,12 @@ int search_and_fopen_nulstr(const char *path, const char *mode, const char *sear
 int create_tmp_dir(char template[], char** dir_name) {
         int r = 0;
         char *d, *dt;
-        mode_t _cleanup_umask_ u;
 
         assert(dir_name);
 
-        u = umask(0077);
-        d = mkdtemp(template);
+        RUN_WITH_UMASK(0077) {
+                d = mkdtemp(template);
+        }
         if (!d) {
                 log_error("Can't create directory %s: %m", template);
                 return -errno;
@@ -5749,9 +5749,10 @@ int create_tmp_dir(char template[], char** dir_name) {
                 goto fail3;
         }
 
-        umask(0000);
-        r = mkdir(dt, 0777);
-        if (r) {
+        RUN_WITH_UMASK(0000) {
+                r = mkdir(dt, 0777);
+        }
+        if (r < 0) {
                 log_error("Can't create directory %s: %m", dt);
                 r = -errno;
                 goto fail2;
diff --git a/src/shared/util.h b/src/shared/util.h
index 7f050758a0..69a47653aa 100644
--- a/src/shared/util.h
+++ b/src/shared/util.h
@@ -616,8 +616,22 @@ char *strrep(const char *s, unsigned n);
 
 void* greedy_realloc(void **p, size_t *allocated, size_t need);
 
-static inline void reset_errno(int *saved_errno) {
+static inline void _reset_errno_(int *saved_errno) {
         errno = *saved_errno;
 }
 
-#define PROTECT_ERRNO __attribute__((cleanup(reset_errno))) int _saved_errno_ = errno
+#define PROTECT_ERRNO __attribute__((cleanup(_reset_errno_))) int _saved_errno_ = errno
+
+struct umask_struct {
+        mode_t mask;
+        bool quit;
+};
+
+static inline void _reset_umask_(struct umask_struct *s) {
+        umask(s->mask);
+};
+
+#define RUN_WITH_UMASK(mask)                                            \
+        for (__attribute__((cleanup(_reset_umask_))) struct umask_struct _saved_umask_ = { umask(mask), false }; \
+             !_saved_umask_.quit ;                                      \
+             _saved_umask_.quit = true)
diff --git a/src/tmpfiles/tmpfiles.c b/src/tmpfiles/tmpfiles.c
index 84f4986503..4e2519d1b5 100644
--- a/src/tmpfiles/tmpfiles.c
+++ b/src/tmpfiles/tmpfiles.c
@@ -454,18 +454,17 @@ static int item_set_perms(Item *i, const char *path) {
 static int write_one_file(Item *i, const char *path) {
         int r, e, fd, flags;
         struct stat st;
-        mode_t u;
 
         flags = i->type == CREATE_FILE ? O_CREAT|O_APPEND :
                 i->type == TRUNCATE_FILE ? O_CREAT|O_TRUNC : 0;
 
-        u = umask(0);
-        label_context_set(path, S_IFREG);
-        fd = open(path, flags|O_NDELAY|O_CLOEXEC|O_WRONLY|O_NOCTTY|O_NOFOLLOW, i->mode);
-        e = errno;
-        label_context_clear();
-        umask(u);
-        errno = e;
+        RUN_WITH_UMASK(0) {
+                label_context_set(path, S_IFREG);
+                fd = open(path, flags|O_NDELAY|O_CLOEXEC|O_WRONLY|O_NOCTTY|O_NOFOLLOW, i->mode);
+                e = errno;
+                label_context_clear();
+                errno = e;
+        }
 
         if (fd < 0) {
                 if (i->type == WRITE_FILE && errno == ENOENT)
@@ -629,7 +628,6 @@ static int glob_item(Item *i, int (*action)(Item *, const char *)) {
 
 static int create_item(Item *i) {
         int r, e;
-        mode_t u;
         struct stat st;
 
         assert(i);
@@ -658,10 +656,10 @@ static int create_item(Item *i) {
         case TRUNCATE_DIRECTORY:
         case CREATE_DIRECTORY:
 
-                u = umask(0);
-                mkdir_parents_label(i->path, 0755);
-                r = mkdir(i->path, i->mode);
-                umask(u);
+                RUN_WITH_UMASK(0000) {
+                        mkdir_parents_label(i->path, 0755);
+                        r = mkdir(i->path, i->mode);
+                }
 
                 if (r < 0 && errno != EEXIST) {
                         log_error("Failed to create directory %s: %m", i->path);
@@ -686,9 +684,9 @@ static int create_item(Item *i) {
 
         case CREATE_FIFO:
 
-                u = umask(0);
-                r = mkfifo(i->path, i->mode);
-                umask(u);
+                RUN_WITH_UMASK(0000) {
+                        r = mkfifo(i->path, i->mode);
+                }
 
                 if (r < 0 && errno != EEXIST) {
                         log_error("Failed to create fifo %s: %m", i->path);
@@ -757,13 +755,13 @@ static int create_item(Item *i) {
 
                 file_type = (i->type == CREATE_BLOCK_DEVICE ? S_IFBLK : S_IFCHR);
 
-                u = umask(0);
-                label_context_set(i->path, file_type);
-                r = mknod(i->path, i->mode | file_type, i->major_minor);
-                e = errno;
-                label_context_clear();
-                umask(u);
-                errno = e;
+                RUN_WITH_UMASK(0000) {
+                        label_context_set(i->path, file_type);
+                        r = mknod(i->path, i->mode | file_type, i->major_minor);
+                        e = errno;
+                        label_context_clear();
+                        errno = e;
+                }
 
                 if (r < 0 && errno != EEXIST) {
                         log_error("Failed to create device node %s: %m", i->path);