tree-wide: drop support for kernels without pidfd_open() and pidfd_send_signal()

Our baseline is v5.4 now.

diff --git a/src/basic/missing_syscall.h b/src/basic/missing_syscall.h
index 75f4b8d81e2605a9270986868731c77e44a4fc8e..7db340095299a5446d854186314df1d2a9109085 100644 (file)
--- a/src/basic/missing_syscall.h
+++ b/src/basic/missing_syscall.h
@@ -299,12 +299,7 @@ static inline long missing_get_mempolicy(int *mode, unsigned long *nodemask,
 
 #if !HAVE_PIDFD_SEND_SIGNAL
 static inline int missing_pidfd_send_signal(int fd, int sig, siginfo_t *info, unsigned flags) {
-#  ifdef __NR_pidfd_send_signal
         return syscall(__NR_pidfd_send_signal, fd, sig, info, flags);
-#  else
-        errno = ENOSYS;
-        return -1;
-#  endif
 }
 
 #  define pidfd_send_signal missing_pidfd_send_signal
@@ -312,12 +307,7 @@ static inline int missing_pidfd_send_signal(int fd, int sig, siginfo_t *info, un
 
 #if !HAVE_PIDFD_OPEN
 static inline int missing_pidfd_open(pid_t pid, unsigned flags) {
-#  ifdef __NR_pidfd_open
         return syscall(__NR_pidfd_open, pid, flags);
-#  else
-        errno = ENOSYS;
-        return -1;
-#  endif
 }
 
 #  define pidfd_open missing_pidfd_open

diff --git a/src/basic/pidfd-util.c b/src/basic/pidfd-util.c
index 204439e4447590cd3fdef0930bd93c8b199491b0..c90699d066ee10d5c731f05fad5cb2aa6650d1df 100644 (file)
--- a/src/basic/pidfd-util.c
+++ b/src/basic/pidfd-util.c
@@ -24,12 +24,8 @@ static int pidfd_check_pidfs(void) {
                 return have_pidfs;
 
         _cleanup_close_ int fd = pidfd_open(getpid_cached(), 0);
-        if (fd < 0) {
-                if (ERRNO_IS_NOT_SUPPORTED(errno))
-                        return (have_pidfs = false);
-
+        if (fd < 0)
                 return -errno;
-        }
 
         return (have_pidfs = fd_is_fs_type(fd, PID_FS_MAGIC));
 }

diff --git a/src/basic/pidref.c b/src/basic/pidref.c
index bc3e96f4266b42288041f95afc78d01c0eb99671..a275f77b5697ffa648c49d86ecf61d3f0b7f5c04 100644 (file)
--- a/src/basic/pidref.c
+++ b/src/basic/pidref.c
@@ -84,8 +84,8 @@ int pidref_set_pid(PidRef *pidref, pid_t pid) {
 
         fd = pidfd_open(pid, 0);
         if (fd < 0) {
-                /* Graceful fallback in case the kernel doesn't support pidfds or is out of fds */
-                if (!ERRNO_IS_NOT_SUPPORTED(errno) && !ERRNO_IS_PRIVILEGE(errno) && !ERRNO_IS_RESOURCE(errno))
+                /* Graceful fallback in case the kernel is out of fds */
+                if (!ERRNO_IS_RESOURCE(errno))
                         return log_debug_errno(errno, "Failed to open pidfd for pid " PID_FMT ": %m", pid);
 
                 fd = -EBADF;

diff --git a/src/libsystemd/sd-event/sd-event.c b/src/libsystemd/sd-event/sd-event.c
index 563b7626fb8b4b4100cde8b74389035d66a16e20..3d1b6fb2285a96722c836f352ee0cd2fe504f4ac 100644 (file)
--- a/src/libsystemd/sd-event/sd-event.c
+++ b/src/libsystemd/sd-event/sd-event.c
@@ -25,6 +25,7 @@
 #include "missing_magic.h"
 #include "missing_syscall.h"
 #include "missing_threads.h"
+#include "missing_wait.h"
 #include "origin-id.h"
 #include "path-util.h"
 #include "prioq.h"
@@ -1074,6 +1075,8 @@ static void source_disconnect(sd_event_source *s) {
 }
 
 static sd_event_source* source_free(sd_event_source *s) {
+        int r;
+
         assert(s);
 
         source_disconnect(s);
@@ -1087,31 +1090,23 @@ static sd_event_source* source_free(sd_event_source *s) {
                 if (s->child.process_owned) {
 
                         if (!s->child.exited) {
-                                bool sent = false;
-
-                                if (s->child.pidfd >= 0) {
-                                        if (pidfd_send_signal(s->child.pidfd, SIGKILL, NULL, 0) < 0) {
-                                                if (errno == ESRCH) /* Already dead */
-                                                        sent = true;
-                                                else if (!ERRNO_IS_NOT_SUPPORTED(errno))
-                                                        log_debug_errno(errno, "Failed to kill process " PID_FMT " via pidfd_send_signal(), re-trying via kill(): %m",
-                                                                        s->child.pid);
-                                        } else
-                                                sent = true;
-                                }
-
-                                if (!sent)
-                                        if (kill(s->child.pid, SIGKILL) < 0)
-                                                if (errno != ESRCH) /* Already dead */
-                                                        log_debug_errno(errno, "Failed to kill process " PID_FMT " via kill(), ignoring: %m",
-                                                                        s->child.pid);
+                                if (s->child.pidfd >= 0)
+                                        r = RET_NERRNO(pidfd_send_signal(s->child.pidfd, SIGKILL, NULL, 0));
+                                else
+                                        r = RET_NERRNO(kill(s->child.pid, SIGKILL));
+                                if (r < 0 && r != -ESRCH)
+                                        log_debug_errno(r, "Failed to kill process " PID_FMT ", ignoring: %m",
+                                                        s->child.pid);
                         }
 
                         if (!s->child.waited) {
                                 siginfo_t si = {};
 
                                 /* Reap the child if we can */
-                                (void) waitid(P_PID, s->child.pid, &si, WEXITED);
+                                if (s->child.pidfd >= 0)
+                                        (void) waitid(P_PIDFD, s->child.pidfd, &si, WEXITED);
+                                else
+                                        (void) waitid(P_PID, s->child.pid, &si, WEXITED);
                         }
                 }
 
@@ -1578,11 +1573,6 @@ static int child_exit_callback(sd_event_source *s, const siginfo_t *si, void *us
         return sd_event_exit(sd_event_source_get_event(s), PTR_TO_INT(userdata));
 }
 
-static bool shall_use_pidfd(void) {
-        /* Mostly relevant for debugging, i.e. this is used in test-event.c to test the event loop once with and once without pidfd */
-        return secure_getenv_bool("SYSTEMD_PIDFD") != 0;
-}
-
 _public_ int sd_event_add_child(
                 sd_event *e,
                 sd_event_source **ret,
@@ -1630,34 +1620,29 @@ _public_ int sd_event_add_child(
         if (!s)
                 return -ENOMEM;
 
+        /* We always take a pidfd here if we can, even if we wait for anything else than WEXITED, so that we
+         * pin the PID, and make regular waitid() handling race-free. */
+
+        s->child.pidfd = pidfd_open(pid, 0);
+        if (s->child.pidfd < 0)
+                return -errno;
+
+        s->child.pidfd_owned = true; /* If we allocate the pidfd we own it by default */
+
         s->wakeup = WAKEUP_EVENT_SOURCE;
         s->child.options = options;
         s->child.callback = callback;
         s->userdata = userdata;
         s->enabled = SD_EVENT_ONESHOT;
 
-        /* We always take a pidfd here if we can, even if we wait for anything else than WEXITED, so that we
-         * pin the PID, and make regular waitid() handling race-free. */
-
-        if (shall_use_pidfd()) {
-                s->child.pidfd = pidfd_open(pid, 0);
-                if (s->child.pidfd < 0) {
-                        /* Propagate errors unless the syscall is not supported or blocked */
-                        if (!ERRNO_IS_NOT_SUPPORTED(errno) && !ERRNO_IS_PRIVILEGE(errno))
-                                return -errno;
-                } else
-                        s->child.pidfd_owned = true; /* If we allocate the pidfd we own it by default */
-        } else
-                s->child.pidfd = -EBADF;
-
         if (EVENT_SOURCE_WATCH_PIDFD(s)) {
-                /* We have a pidfd and we only want to watch for exit */
+                /* We only want to watch for exit */
                 r = source_child_pidfd_register(s, s->enabled);
                 if (r < 0)
                         return r;
 
         } else {
-                /* We have no pidfd or we shall wait for some other event than WEXITED */
+                /* We shall wait for some other event than WEXITED */
                 r = event_make_signal_data(e, SIGCHLD, NULL);
                 if (r < 0)
                         return r;
@@ -3239,12 +3224,10 @@ _public_ int sd_event_source_send_child_signal(sd_event_source *s, int sig, cons
                 if (si)
                         copy = *si;
 
-                if (pidfd_send_signal(s->child.pidfd, sig, si ? &copy : NULL, 0) < 0) {
-                        /* Let's propagate the error only if the system call is not implemented or prohibited */
-                        if (!ERRNO_IS_NOT_SUPPORTED(errno) && !ERRNO_IS_PRIVILEGE(errno))
-                                return -errno;
-                } else
-                        return 0;
+                if (pidfd_send_signal(s->child.pidfd, sig, si ? &copy : NULL, 0) < 0)
+                        return -errno;
+
+                return 0;
         }
 
         /* Flags are only supported for pidfd_send_signal(), not for rt_sigqueueinfo(), hence let's refuse

diff --git a/src/libsystemd/sd-event/test-event.c b/src/libsystemd/sd-event/test-event.c
index 57dee392d74fd178f7910f6945b2278bf097eb9a..6394507994fba68b8797f0ec7d8bdd84ac70e376 100644 (file)
--- a/src/libsystemd/sd-event/test-event.c
+++ b/src/libsystemd/sd-event/test-event.c
@@ -198,7 +198,7 @@ static int post_handler(sd_event_source *s, void *userdata) {
         return 2;
 }
 
-static void test_basic_one(bool with_pidfd) {
+TEST(basic) {
         sd_event *e = NULL;
         sd_event_source *w = NULL, *x = NULL, *y = NULL, *z = NULL, *q = NULL, *t = NULL;
         static const char ch = 'x';
@@ -207,10 +207,6 @@ static void test_basic_one(bool with_pidfd) {
         uint64_t event_now;
         int64_t priority;
 
-        log_info("/* %s(pidfd=%s) */", __func__, yes_no(with_pidfd));
-
-        assert_se(setenv("SYSTEMD_PIDFD", yes_no(with_pidfd), 1) >= 0);
-
         assert_se(pipe(a) >= 0);
         assert_se(pipe(b) >= 0);
         assert_se(pipe(d) >= 0);
@@ -301,13 +297,6 @@ static void test_basic_one(bool with_pidfd) {
         safe_close_pair(b);
         safe_close_pair(d);
         safe_close_pair(k);
-
-        assert_se(unsetenv("SYSTEMD_PIDFD") >= 0);
-}
-
-TEST(basic) {
-        test_basic_one(true);   /* test with pidfd */
-        test_basic_one(false);  /* test without pidfd */
 }
 
 TEST(sd_event_now) {
@@ -583,13 +572,7 @@ TEST(pidfd) {
 
         assert_se(pid > 1);
 
-        pidfd = pidfd_open(pid, 0);
-        if (pidfd < 0) {
-                /* No pidfd_open() supported or blocked? */
-                assert_se(ERRNO_IS_NOT_SUPPORTED(errno) || ERRNO_IS_PRIVILEGE(errno));
-                (void) wait_for_terminate(pid, NULL);
-                return;
-        }
+        ASSERT_OK(pidfd = pidfd_open(pid, 0));
 
         pid2 = fork();
         if (pid2 == 0)

diff --git a/src/login/pam_systemd.c b/src/login/pam_systemd.c
index e0861f934c8208e5e6a48c1099ccde3fbe6d421e..ed08eb6cf831bb26105b2d2f347ed55127318fba 100644 (file)
--- a/src/login/pam_systemd.c
+++ b/src/login/pam_systemd.c
@@ -876,7 +876,7 @@ static int create_session_message(
 
         if (!avoid_pidfd) {
                 pidfd = pidfd_open(getpid_cached(), 0);
-                if (pidfd < 0 && !ERRNO_IS_NOT_SUPPORTED(errno) && !ERRNO_IS_PRIVILEGE(errno))
+                if (pidfd < 0)
                         return -errno;
         }