chiark / gitweb /
nspawn: allow passing socket activation fds through nspawn
[elogind.git] / src / nspawn / nspawn.c
index 5cac32cd8c84312ce28b97cfd515ecab1c2a7dba..f5fb59d2d4affb7f07713aa6ff1ce5a9c4a57193 100644 (file)
@@ -55,6 +55,7 @@
 #include "loopback-setup.h"
 #include "sd-id128.h"
 #include "dev-setup.h"
+#include "fdset.h"
 
 typedef enum LinkJournal {
         LINK_NO,
@@ -668,58 +669,58 @@ static int setup_hostname(void) {
 
 static int setup_journal(const char *directory) {
         sd_id128_t machine_id;
-        char *p = NULL, *b = NULL, *l, *q = NULL, *d = NULL;
+        char _cleanup_free_ *p = NULL, *b = NULL, *q = NULL, *d = NULL;
+        char *id;
         int r;
 
         if (arg_link_journal == LINK_NO)
                 return 0;
 
         p = strappend(directory, "/etc/machine-id");
-        if (!p) {
-                r = log_oom();
-                goto finish;
-        }
+        if (!p)
+                return log_oom();
 
         r = read_one_line_file(p, &b);
-        if (r == -ENOENT && arg_link_journal == LINK_AUTO) {
-                r = 0;
-                goto finish;
-        } else if (r < 0) {
-                log_error("Failed to read machine ID: %s", strerror(-r));
+        if (r == -ENOENT && arg_link_journal == LINK_AUTO)
+                return 0;
+        else if (r < 0) {
+                log_error("Failed to read machine ID from %s: %s", p, strerror(-r));
                 return r;
         }
 
-        l = strstrip(b);
-        if (isempty(l) && arg_link_journal == LINK_AUTO) {
-                r = 0;
-                goto finish;
-        }
+        id = strstrip(b);
+        if (isempty(id) && arg_link_journal == LINK_AUTO)
+                return 0;
 
-        /* Verify validaty */
-        r = sd_id128_from_string(l, &machine_id);
+        /* Verify validity */
+        r = sd_id128_from_string(id, &machine_id);
         if (r < 0) {
-                log_error("Failed to parse machine ID: %s", strerror(-r));
-                goto finish;
+                log_error("Failed to parse machine ID from %s: %s", p, strerror(-r));
+                return r;
         }
 
         free(p);
-        p = strappend("/var/log/journal/", l);
-        q = strjoin(directory, "/var/log/journal/", l, NULL);
-        if (!p || !q) {
-                r = log_oom();
-                goto finish;
+        p = strappend("/var/log/journal/", id);
+        q = strjoin(directory, "/var/log/journal/", id, NULL);
+        if (!p || !q)
+                return log_oom();
+
+        if (path_is_mount_point(p, false) > 0) {
+                if (arg_link_journal != LINK_AUTO) {
+                        log_error("%s: already a mount point, refusing to use for journal", p);
+                        return -EEXIST;
+                }
+
+                return 0;
         }
 
-        if (path_is_mount_point(p, false) > 0 ||
-            path_is_mount_point(q, false) > 0) {
+        if (path_is_mount_point(q, false) > 0) {
                 if (arg_link_journal != LINK_AUTO) {
-                        log_error("Journal already a mount point, refusing.");
-                        r = -EEXIST;
-                        goto finish;
+                        log_error("%s: already a mount point, refusing to use for journal", q);
+                        return -EEXIST;
                 }
 
-                r = 0;
-                goto finish;
+                return 0;
         }
 
         r = readlink_and_make_absolute(p, &d);
@@ -728,89 +729,74 @@ static int setup_journal(const char *directory) {
                      arg_link_journal == LINK_AUTO) &&
                     path_equal(d, q)) {
 
-                        mkdir_p(q, 0755);
-
-                        r = 0;
-                        goto finish;
+                        r = mkdir_p(q, 0755);
+                        if (r < 0)
+                                log_warning("failed to create directory %s: %m", q);
+                        return 0;
                 }
 
                 if (unlink(p) < 0) {
                         log_error("Failed to remove symlink %s: %m", p);
-                        r = -errno;
-                        goto finish;
+                        return -errno;
                 }
         } else if (r == -EINVAL) {
 
                 if (arg_link_journal == LINK_GUEST &&
                     rmdir(p) < 0) {
 
-                        if (errno == ENOTDIR)
-                                log_error("%s already exists and is neither symlink nor directory.", p);
-                        else {
+                        if (errno == ENOTDIR) {
+                                log_error("%s already exists and is neither a symlink nor a directory", p);
+                                return r;
+                        } else {
                                 log_error("Failed to remove %s: %m", p);
-                                r = -errno;
+                                return -errno;
                         }
-
-                        goto finish;
                 }
         } else if (r != -ENOENT) {
                 log_error("readlink(%s) failed: %m", p);
-                goto finish;
+                return r;
         }
 
         if (arg_link_journal == LINK_GUEST) {
 
                 if (symlink(q, p) < 0) {
                         log_error("Failed to symlink %s to %s: %m", q, p);
-                        r = -errno;
-                        goto finish;
+                        return -errno;
                 }
 
-                mkdir_p(q, 0755);
-
-                r = 0;
-                goto finish;
+                r = mkdir_p(q, 0755);
+                if (r < 0)
+                        log_warning("failed to create directory %s: %m", q);
+                return 0;
         }
 
         if (arg_link_journal == LINK_HOST) {
                 r = mkdir_p(p, 0755);
                 if (r < 0) {
                         log_error("Failed to create %s: %m", p);
-                        goto finish;
+                        return r;
                 }
 
-        } else if (access(p, F_OK) < 0) {
-                r = 0;
-                goto finish;
-        }
+        } else if (access(p, F_OK) < 0)
+                return 0;
 
         if (dir_is_empty(q) == 0) {
                 log_error("%s not empty.", q);
-                r = -ENOTEMPTY;
-                goto finish;
+                return -ENOTEMPTY;
         }
 
         r = mkdir_p(q, 0755);
         if (r < 0) {
                 log_error("Failed to create %s: %m", q);
-                goto finish;
+                return r;
         }
 
         if (mount(p, q, "bind", MS_BIND, NULL) < 0) {
                 log_error("Failed to bind mount journal from host into guest: %m");
-                r = -errno;
-                goto finish;
+                return -errno;
         }
 
-        r = 0;
-
-finish:
-        free(p);
-        free(q);
-        free(d);
-        free(b);
-        return r;
-
+        return 0;
 }
 
 static int drop_capabilities(void) {
@@ -857,9 +843,19 @@ static int process_pty(int master, sigset_t *mask) {
                 goto finish;
         }
 
-        zero(stdin_ev);
-        stdin_ev.events = EPOLLIN|EPOLLET;
-        stdin_ev.data.fd = STDIN_FILENO;
+        /* We read from STDIN only if this is actually a TTY,
+         * otherwise we assume non-interactivity. */
+        if (isatty(STDIN_FILENO)) {
+                zero(stdin_ev);
+                stdin_ev.events = EPOLLIN|EPOLLET;
+                stdin_ev.data.fd = STDIN_FILENO;
+
+                if (epoll_ctl(ep, EPOLL_CTL_ADD, STDIN_FILENO, &stdin_ev) < 0) {
+                        log_error("Failed to register STDIN in epoll: %m");
+                        r = -errno;
+                        goto finish;
+                }
+        }
 
         zero(stdout_ev);
         stdout_ev.events = EPOLLOUT|EPOLLET;
@@ -873,11 +869,10 @@ static int process_pty(int master, sigset_t *mask) {
         signal_ev.events = EPOLLIN;
         signal_ev.data.fd = signal_fd;
 
-        if (epoll_ctl(ep, EPOLL_CTL_ADD, STDIN_FILENO, &stdin_ev) < 0 ||
-            epoll_ctl(ep, EPOLL_CTL_ADD, STDOUT_FILENO, &stdout_ev) < 0 ||
+        if (epoll_ctl(ep, EPOLL_CTL_ADD, STDOUT_FILENO, &stdout_ev) < 0 ||
             epoll_ctl(ep, EPOLL_CTL_ADD, master, &master_ev) < 0 ||
             epoll_ctl(ep, EPOLL_CTL_ADD, signal_fd, &signal_ev) < 0) {
-                log_error("Failed to regiser fds in epoll: %m");
+                log_error("Failed to register fds in epoll: %m");
                 r = -errno;
                 goto finish;
         }
@@ -1047,13 +1042,14 @@ int main(int argc, char *argv[]) {
         int r = EXIT_FAILURE, k;
         char *oldcg = NULL, *newcg = NULL;
         char **controller = NULL;
-        int master = -1;
+        int master = -1, n_fd_passed;
         const char *console = NULL;
         struct termios saved_attr, raw_attr;
         sigset_t mask;
         bool saved_attr_valid = false;
         struct winsize ws;
         int kmsg_socket_pair[2] = { -1, -1 };
+        FDSet *fds = NULL;
 
         log_parse_environment();
         log_open();
@@ -1098,6 +1094,18 @@ int main(int argc, char *argv[]) {
                 goto finish;
         }
 
+        log_close();
+        n_fd_passed = sd_listen_fds(false);
+        if (n_fd_passed > 0) {
+                k = fdset_new_listen_fds(&fds, false);
+                if (k < 0) {
+                        log_error("Failed to collect file descriptors: %s", strerror(-k));
+                        goto finish;
+                }
+        }
+        fdset_close_others(fds);
+        log_open();
+
         k = cg_get_by_pid(SYSTEMD_CGROUP_CONTROLLER, 0, &oldcg);
         if (k < 0) {
                 log_error("Failed to determine current cgroup: %s", strerror(-k));
@@ -1143,16 +1151,13 @@ int main(int argc, char *argv[]) {
                 goto finish;
         }
 
-        if (tcgetattr(STDIN_FILENO, &saved_attr) < 0) {
-                log_error("Failed to get terminal attributes: %m");
-                goto finish;
-        }
-
-        saved_attr_valid = true;
+        if (tcgetattr(STDIN_FILENO, &saved_attr) >= 0) {
+                saved_attr_valid = true;
 
-        raw_attr = saved_attr;
-        cfmakeraw(&raw_attr);
-        raw_attr.c_lflag &= ~ECHO;
+                raw_attr = saved_attr;
+                cfmakeraw(&raw_attr);
+                raw_attr.c_lflag &= ~ECHO;
+        }
 
         if (socketpair(AF_UNIX, SOCK_DGRAM|SOCK_NONBLOCK|SOCK_CLOEXEC, 0, kmsg_socket_pair) < 0) {
                 log_error("Failed to create kmsg socket pair");
@@ -1166,9 +1171,11 @@ int main(int argc, char *argv[]) {
         for (;;) {
                 siginfo_t status;
 
-                if (tcsetattr(STDIN_FILENO, TCSANOW, &raw_attr) < 0) {
-                        log_error("Failed to set terminal attributes: %m");
-                        goto finish;
+                if (saved_attr_valid) {
+                        if (tcsetattr(STDIN_FILENO, TCSANOW, &raw_attr) < 0) {
+                                log_error("Failed to set terminal attributes: %m");
+                                goto finish;
+                        }
                 }
 
                 pid = syscall(__NR_clone, SIGCHLD|CLONE_NEWIPC|CLONE_NEWNS|CLONE_NEWPID|CLONE_NEWUTS|(arg_private_network ? CLONE_NEWNET : 0), NULL);
@@ -1187,6 +1194,7 @@ int main(int argc, char *argv[]) {
                         const char *home = NULL;
                         uid_t uid = (uid_t) -1;
                         gid_t gid = (gid_t) -1;
+                        unsigned n_env = 0;
                         const char *envp[] = {
                                 "PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin",
                                 "container=systemd-nspawn", /* LXC sets container=lxc, so follow the scheme here */
@@ -1195,28 +1203,45 @@ int main(int argc, char *argv[]) {
                                 NULL, /* USER */
                                 NULL, /* LOGNAME */
                                 NULL, /* container_uuid */
+                                NULL, /* LISTEN_FDS */
+                                NULL, /* LISTEN_PID */
                                 NULL
                         };
 
                         envp[2] = strv_find_prefix(environ, "TERM=");
+                        n_env = 3;
 
                         close_nointr_nofail(master);
+                        master = -1;
 
                         close_nointr(STDIN_FILENO);
                         close_nointr(STDOUT_FILENO);
                         close_nointr(STDERR_FILENO);
 
-                        close_all_fds(&kmsg_socket_pair[1], 1);
+                        close_nointr_nofail(kmsg_socket_pair[0]);
+                        kmsg_socket_pair[0] = -1;
 
                         reset_all_signal_handlers();
 
                         assert_se(sigemptyset(&mask) == 0);
                         assert_se(sigprocmask(SIG_SETMASK, &mask, NULL) == 0);
 
-                        if (open_terminal(console, O_RDWR) != STDIN_FILENO ||
-                            dup2(STDIN_FILENO, STDOUT_FILENO) != STDOUT_FILENO ||
-                            dup2(STDIN_FILENO, STDERR_FILENO) != STDERR_FILENO)
+                        k = open_terminal(console, O_RDWR);
+                        if (k != STDIN_FILENO) {
+                                if (k >= 0) {
+                                        close_nointr_nofail(k);
+                                        k = -EINVAL;
+                                }
+
+                                log_error("Failed to open console: %s", strerror(-k));
                                 goto child_fail;
+                        }
+
+                        if (dup2(STDIN_FILENO, STDOUT_FILENO) != STDOUT_FILENO ||
+                            dup2(STDIN_FILENO, STDERR_FILENO) != STDERR_FILENO) {
+                                log_error("Failed to duplicate console: %m");
+                                goto child_fail;
+                        }
 
                         if (setsid() < 0) {
                                 log_error("setsid() failed: %m");
@@ -1263,6 +1288,7 @@ int main(int argc, char *argv[]) {
                                 goto child_fail;
 
                         close_nointr_nofail(kmsg_socket_pair[1]);
+                        kmsg_socket_pair[1] = -1;
 
                         if (setup_boot_id(arg_directory) < 0)
                                 goto child_fail;
@@ -1342,17 +1368,48 @@ int main(int argc, char *argv[]) {
                                         log_error("setreuid() failed: %m");
                                         goto child_fail;
                                 }
+                        } else {
+                                /* Reset everything fully to 0, just in case */
+
+                                if (setgroups(0, NULL) < 0) {
+                                        log_error("setgroups() failed: %m");
+                                        goto child_fail;
+                                }
+
+                                if (setresgid(0, 0, 0) < 0) {
+                                        log_error("setregid() failed: %m");
+                                        goto child_fail;
+                                }
+
+                                if (setresuid(0, 0, 0) < 0) {
+                                        log_error("setreuid() failed: %m");
+                                        goto child_fail;
+                                }
                         }
 
-                        if ((asprintf((char**)(envp + 3), "HOME=%s", home ? home: "/root") < 0) ||
-                            (asprintf((char**)(envp + 4), "USER=%s", arg_user ? arg_user : "root") < 0) ||
-                            (asprintf((char**)(envp + 5), "LOGNAME=%s", arg_user ? arg_user : "root") < 0)) {
+                        if ((asprintf((char**)(envp + n_env++), "HOME=%s", home ? home: "/root") < 0) ||
+                            (asprintf((char**)(envp + n_env++), "USER=%s", arg_user ? arg_user : "root") < 0) ||
+                            (asprintf((char**)(envp + n_env++), "LOGNAME=%s", arg_user ? arg_user : "root") < 0)) {
                                 log_oom();
                                 goto child_fail;
                         }
 
                         if (arg_uuid) {
-                                if (asprintf((char**)(envp + 6), "container_uuid=%s", arg_uuid) < 0) {
+                                if (asprintf((char**)(envp + n_env++), "container_uuid=%s", arg_uuid) < 0) {
+                                        log_oom();
+                                        goto child_fail;
+                                }
+                        }
+
+                        if (fdset_size(fds) > 0) {
+                                k = fdset_cloexec(fds, false);
+                                if (k < 0) {
+                                        log_error("Failed to unset O_CLOEXEC for file descriptors.");
+                                        goto child_fail;
+                                }
+
+                                if ((asprintf((char **)(envp + n_env++), "LISTEN_FDS=%u", n_fd_passed) < 0) ||
+                                    (asprintf((char **)(envp + n_env++), "LISTEN_PID=%lu", (unsigned long) getpid()) < 0)) {
                                         log_oom();
                                         goto child_fail;
                                 }
@@ -1391,10 +1448,12 @@ int main(int argc, char *argv[]) {
                         _exit(EXIT_FAILURE);
                 }
 
+                fdset_free(fds);
+                fds = NULL;
+
                 if (process_pty(master, &mask) < 0)
                         goto finish;
 
-
                 if (saved_attr_valid)
                         tcsetattr(STDIN_FILENO, TCSANOW, &saved_attr);
 
@@ -1455,5 +1514,7 @@ finish:
         free(oldcg);
         free(newcg);
 
+        fdset_free(fds);
+
         return r;
 }