Merge pull request #10747 from poettering/machinectl-list-fix

properly acquire os-release file from containers

src/basic/process-util.c

@@ -1409,6 +1409,60 @@ int safe_fork_full(
         return 0;
 }
 
+int namespace_fork(
+                const char *outer_name,
+                const char *inner_name,
+                const int except_fds[],
+                size_t n_except_fds,
+                ForkFlags flags,
+                int pidns_fd,
+                int mntns_fd,
+                int netns_fd,
+                int userns_fd,
+                int root_fd,
+                pid_t *ret_pid) {
+
+        int r;
+
+        /* This is much like safe_fork(), but forks twice, and joins the specified namespaces in the middle
+         * process. This ensures that we are fully a member of the destination namespace, with pidns an all, so that
+         * /proc/self/fd works correctly. */
+
+        r = safe_fork_full(outer_name, except_fds, n_except_fds, (flags|FORK_DEATHSIG) & ~(FORK_REOPEN_LOG|FORK_NEW_MOUNTNS|FORK_MOUNTNS_SLAVE), ret_pid);
+        if (r < 0)
+                return r;
+        if (r == 0) {
+                pid_t pid;
+
+                /* Child */
+
+                r = namespace_enter(pidns_fd, mntns_fd, netns_fd, userns_fd, root_fd);
+                if (r < 0) {
+                        log_full_errno(FLAGS_SET(flags, FORK_LOG) ? LOG_ERR : LOG_DEBUG, r, "Failed to join namespace: %m");
+                        _exit(EXIT_FAILURE);
+                }
+
+                /* We mask a few flags here that either make no sense for the grandchild, or that we don't have to do again */
+                r = safe_fork_full(inner_name, except_fds, n_except_fds, flags & ~(FORK_WAIT|FORK_RESET_SIGNALS|FORK_CLOSE_ALL_FDS|FORK_NULL_STDIO), &pid);
+                if (r < 0)
+                        _exit(EXIT_FAILURE);
+                if (r == 0) {
+                        /* Child */
+                        if (ret_pid)
+                                *ret_pid = pid;
+                        return 0;
+                }
+
+                r = wait_for_terminate_and_check(inner_name, pid, FLAGS_SET(flags, FORK_LOG) ? WAIT_LOG : 0);
+                if (r < 0)
+                        _exit(EXIT_FAILURE);
+
+                _exit(r);
+        }
+
+        return 1;
+}
+
 int fork_agent(const char *name, const int except[], size_t n_except, pid_t *ret_pid, const char *path, ...) {
         bool stdout_is_tty, stderr_is_tty;
         size_t n, i;

src/basic/process-util.h

@@ -159,6 +159,8 @@ static inline int safe_fork(const char *name, ForkFlags flags, pid_t *ret_pid) {
         return safe_fork_full(name, NULL, 0, flags, ret_pid);
 }
 
+int namespace_fork(const char *outer_name, const char *inner_name, const int except_fds[], size_t n_except_fds, ForkFlags flags, int pidns_fd, int mntns_fd, int netns_fd, int userns_fd, int root_fd, pid_t *ret_pid);
+
 int fork_agent(const char *name, const int except[], size_t n_except, pid_t *pid, const char *path, ...) _sentinel_;
 
 int set_oom_score_adjust(int value);

src/basic/terminal-util.c

@@ -1095,7 +1095,8 @@ int openpt_in_namespace(pid_t pid, int flags) {
         if (socketpair(AF_UNIX, SOCK_DGRAM, 0, pair) < 0)
                 return -errno;
 
-        r = safe_fork("(sd-openpt)", FORK_RESET_SIGNALS|FORK_DEATHSIG, &child);
+        r = namespace_fork("(sd-openptns)", "(sd-openpt)", NULL, 0, FORK_RESET_SIGNALS|FORK_DEATHSIG,
+                           pidnsfd, mntnsfd, -1, usernsfd, rootfd, &child);
         if (r < 0)
                 return r;
         if (r == 0) {
@@ -1103,10 +1104,6 @@ int openpt_in_namespace(pid_t pid, int flags) {
 
                 pair[0] = safe_close(pair[0]);
 
-                r = namespace_enter(pidnsfd, mntnsfd, -1, usernsfd, rootfd);
-                if (r < 0)
-                        _exit(EXIT_FAILURE);
-
                 master = posix_openpt(flags|O_NOCTTY|O_CLOEXEC);
                 if (master < 0)
                         _exit(EXIT_FAILURE);
@@ -1122,7 +1119,7 @@ int openpt_in_namespace(pid_t pid, int flags) {
 
         pair[1] = safe_close(pair[1]);
 
-        r = wait_for_terminate_and_check("(sd-openpt)", child, 0);
+        r = wait_for_terminate_and_check("(sd-openptns)", child, 0);
         if (r < 0)
                 return r;
         if (r != EXIT_SUCCESS)
@@ -1144,7 +1141,8 @@ int open_terminal_in_namespace(pid_t pid, const char *name, int mode) {
         if (socketpair(AF_UNIX, SOCK_DGRAM, 0, pair) < 0)
                 return -errno;
 
-        r = safe_fork("(sd-terminal)", FORK_RESET_SIGNALS|FORK_DEATHSIG, &child);
+        r = namespace_fork("(sd-terminalns)", "(sd-terminal)", NULL, 0, FORK_RESET_SIGNALS|FORK_DEATHSIG,
+                           pidnsfd, mntnsfd, -1, usernsfd, rootfd, &child);
         if (r < 0)
                 return r;
         if (r == 0) {
@@ -1152,10 +1150,6 @@ int open_terminal_in_namespace(pid_t pid, const char *name, int mode) {
 
                 pair[0] = safe_close(pair[0]);
 
-                r = namespace_enter(pidnsfd, mntnsfd, -1, usernsfd, rootfd);
-                if (r < 0)
-                        _exit(EXIT_FAILURE);
-
                 master = open_terminal(name, mode|O_NOCTTY|O_CLOEXEC);
                 if (master < 0)
                         _exit(EXIT_FAILURE);
@@ -1168,7 +1162,7 @@ int open_terminal_in_namespace(pid_t pid, const char *name, int mode) {
 
         pair[1] = safe_close(pair[1]);
 
-        r = wait_for_terminate_and_check("(sd-terminal)", child, 0);
+        r = wait_for_terminate_and_check("(sd-terminalns)", child, 0);
         if (r < 0)
                 return r;
         if (r != EXIT_SUCCESS)