Merge pull request #25266 from poettering/dissect-fsck-fix

dissect: fix fsck invocation

src/basic/fd-util.c

@@ -174,12 +174,35 @@ int fd_cloexec(int fd, bool cloexec) {
         return RET_NERRNO(fcntl(fd, F_SETFD, nflags));
 }
 
+int fd_cloexec_many(const int fds[], size_t n_fds, bool cloexec) {
+        int ret = 0, r;
+
+        assert(n_fds == 0 || fds);
+
+        for (size_t i = 0; i < n_fds; i++) {
+                if (fds[i] < 0) /* Skip gracefully over already invalidated fds */
+                        continue;
+
+                r = fd_cloexec(fds[i], cloexec);
+                if (r < 0 && ret >= 0) /* Continue going, but return first error */
+                        ret = r;
+                else
+                        ret = 1; /* report if we did anything */
+        }
+
+        return ret;
+}
+
 _pure_ static bool fd_in_set(int fd, const int fdset[], size_t n_fdset) {
         assert(n_fdset == 0 || fdset);
 
-        for (size_t i = 0; i < n_fdset; i++)
+        for (size_t i = 0; i < n_fdset; i++) {
+                if (fdset[i] < 0)
+                        continue;
+
                 if (fdset[i] == fd)
                         return true;
+        }
 
         return false;
 }
@@ -252,6 +275,10 @@ static int close_all_fds_special_case(const int except[], size_t n_except) {
         if (!have_close_range)
                 return 0;
 
+        if (n_except == 1 && except[0] < 0) /* Minor optimization: if we only got one fd, and it's invalid,
+                                             * we got none */
+                n_except = 0;
+
         switch (n_except) {
 
         case 0:

src/basic/fd-util.h

@@ -56,6 +56,7 @@ DEFINE_TRIVIAL_CLEANUP_FUNC_FULL(DIR*, closedir, NULL);
 
 int fd_nonblock(int fd, bool nonblock);
 int fd_cloexec(int fd, bool cloexec);
+int fd_cloexec_many(const int fds[], size_t n_fds, bool cloexec);
 
 int get_max_fd(void);
 

src/basic/process-util.c

@@ -1372,6 +1372,14 @@ int safe_fork_full(
                 }
         }
 
+        if (flags & FORK_CLOEXEC_OFF) {
+                r = fd_cloexec_many(except_fds, n_except_fds, false);
+                if (r < 0) {
+                        log_full_errno(prio, r, "Failed to turn off O_CLOEXEC on file descriptors: %m");
+                        _exit(EXIT_FAILURE);
+                }
+        }
+
         /* When we were asked to reopen the logs, do so again now */
         if (flags & FORK_REOPEN_LOG) {
                 log_open();

src/basic/process-util.h

@@ -150,6 +150,7 @@ typedef enum ForkFlags {
         FORK_STDOUT_TO_STDERR   = 1 << 11, /* Make stdout a copy of stderr */
         FORK_FLUSH_STDIO        = 1 << 12, /* fflush() stdout (and stderr) before forking */
         FORK_NEW_USERNS         = 1 << 13, /* Run child in its own user namespace */
+        FORK_CLOEXEC_OFF        = 1 << 14, /* In the child: turn off O_CLOEXEC on all fds in except_fds[] */
 } ForkFlags;
 
 int safe_fork_full(const char *name, const int except_fds[], size_t n_except_fds, ForkFlags flags, pid_t *ret_pid);

src/shared/dissect-image.c

@@ -1327,11 +1327,11 @@ static int is_loop_device(const char *path) {
         return true;
 }
 
-static int run_fsck(const char *node, const char *fstype) {
+static int run_fsck(int node_fd, const char *fstype) {
         int r, exit_status;
         pid_t pid;
 
-        assert(node);
+        assert(node_fd >= 0);
         assert(fstype);
 
         r = fsck_exists_for_fstype(fstype);
@@ -1340,16 +1340,20 @@ static int run_fsck(const char *node, const char *fstype) {
                 return 0;
         }
         if (r == 0) {
-                log_debug("Not checking partition %s, as fsck for %s does not exist.", node, fstype);
+                log_debug("Not checking partition %s, as fsck for %s does not exist.", FORMAT_PROC_FD_PATH(node_fd), fstype);
                 return 0;
         }
 
-        r = safe_fork("(fsck)", FORK_RESET_SIGNALS|FORK_CLOSE_ALL_FDS|FORK_RLIMIT_NOFILE_SAFE|FORK_DEATHSIG|FORK_NULL_STDIO, &pid);
+        r = safe_fork_full(
+                        "(fsck)",
+                        &node_fd, 1, /* Leave the node fd open */
+                        FORK_RESET_SIGNALS|FORK_CLOSE_ALL_FDS|FORK_RLIMIT_NOFILE_SAFE|FORK_DEATHSIG|FORK_NULL_STDIO|FORK_CLOEXEC_OFF,
+                        &pid);
         if (r < 0)
                 return log_debug_errno(r, "Failed to fork off fsck: %m");
         if (r == 0) {
                 /* Child */
-                execl("/sbin/fsck", "/sbin/fsck", "-aT", node, NULL);
+                execl("/sbin/fsck", "/sbin/fsck", "-aT", FORMAT_PROC_FD_PATH(node_fd), NULL);
                 log_open();
                 log_debug_errno(errno, "Failed to execl() fsck: %m");
                 _exit(FSCK_OPERATIONAL_ERROR);
@@ -1439,7 +1443,7 @@ static int mount_partition(
         rw = m->rw && !(flags & DISSECT_IMAGE_MOUNT_READ_ONLY);
 
         if (FLAGS_SET(flags, DISSECT_IMAGE_FSCK) && rw) {
-                r = run_fsck(node, fstype);
+                r = run_fsck(m->mount_node_fd, fstype);
                 if (r < 0)
                         return r;
         }