Merge pull request #27890 from bluca/executor

core: add systemd-executor binary

src/basic/cgroup-util.h

@@ -36,7 +36,7 @@ typedef enum CGroupController {
         CGROUP_CONTROLLER_BPF_SOCKET_BIND,
         CGROUP_CONTROLLER_BPF_RESTRICT_NETWORK_INTERFACES,
         /* The BPF hook implementing RestrictFileSystems= is not defined here.
-         * It's applied as late as possible in exec_child() so we don't block
+         * It's applied as late as possible in exec_invoke() so we don't block
          * our own unit setup code. */
 
         _CGROUP_CONTROLLER_MAX,

src/basic/env-util.c

@@ -1074,3 +1074,22 @@ int getenv_steal_erase(const char *name, char **ret) {
 
         return 1;
 }
+
+int set_full_environment(char **env) {
+        int r;
+
+        clearenv();
+
+        STRV_FOREACH(e, env) {
+                _cleanup_free_ char *k = NULL, *v = NULL;
+
+                r = split_pair(*e, "=", &k, &v);
+                if (r < 0)
+                        return r;
+
+                if (setenv(k, v, /* overwrite= */ true) < 0)
+                        return -errno;
+        }
+
+        return 0;
+}

src/basic/env-util.h

@@ -77,3 +77,5 @@ int setenv_systemd_exec_pid(bool update_only);
 int getenv_path_list(const char *name, char ***ret_paths);
 
 int getenv_steal_erase(const char *name, char **ret);
+
+int set_full_environment(char **env);

src/basic/process-util.c

@@ -5,6 +5,7 @@
 #include <limits.h>
 #include <linux/oom.h>
 #include <pthread.h>
+#include <spawn.h>
 #include <stdbool.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -1732,6 +1733,51 @@ int make_reaper_process(bool b) {
         return 0;
 }
 
+int posix_spawn_wrapper(const char *path, char *const *argv, char *const *envp, pid_t *ret_pid) {
+        posix_spawnattr_t attr;
+        sigset_t mask;
+        pid_t pid;
+        int r;
+
+        /* Forks and invokes 'path' with 'argv' and 'envp' using CLONE_VM and CLONE_VFORK, which means the
+         * caller will be blocked until the child either exits or exec's. The memory of the child will be
+         * fully shared with the memory of the parent, so that there are no copy-on-write or memory.max
+         * issues. */
+
+        assert(path);
+        assert(argv);
+        assert(ret_pid);
+
+        assert_se(sigfillset(&mask) >= 0);
+
+        r = posix_spawnattr_init(&attr);
+        if (r != 0)
+                return -r; /* These functions return a positive errno on failure */
+        r = posix_spawnattr_setflags(&attr, POSIX_SPAWN_SETSIGMASK);
+        if (r != 0)
+                goto fail;
+        r = posix_spawnattr_setflags(&attr, POSIX_SPAWN_SETSIGDEF); /* Set all signals to SIG_DFL */
+        if (r != 0)
+                goto fail;
+        r = posix_spawnattr_setsigmask(&attr, &mask);
+        if (r != 0)
+                goto fail;
+
+        r = posix_spawn(&pid, path, NULL, &attr, argv, envp);
+        if (r != 0)
+                goto fail;
+
+        *ret_pid = pid;
+
+        posix_spawnattr_destroy(&attr);
+        return 0;
+
+fail:
+        assert(r > 0);
+        posix_spawnattr_destroy(&attr);
+        return -r;
+}
+
 static const char *const sigchld_code_table[] = {
         [CLD_EXITED] = "exited",
         [CLD_KILLED] = "killed",

src/basic/process-util.h

@@ -210,3 +210,5 @@ int get_process_threads(pid_t pid);
 
 int is_reaper_process(void);
 int make_reaper_process(bool b);
+
+int posix_spawn_wrapper(const char *path, char *const *argv, char *const *envp, pid_t *ret_pid);