tree-wide: port to fd_wait_for_event()

Prompted by the discussion on #16110, let's migrate more code to
fd_wait_for_event().

This only leaves 7 places where we call into poll()/poll() directly in
our entire codebase. (one of which is fd_wait_for_event() itself)

11 files changed, 63 insertions, 163 deletions

diff --git a/src/basic/io-util.c b/src/basic/io-util.c
index 4b3d1c814f..18baadb1fe 100644
--- a/src/basic/io-util.c
+++ b/src/basic/io-util.c
@@ -11,10 +11,6 @@
 #include "time-util.h"
 
 int flush_fd(int fd) {
-        struct pollfd pollfd = {
-                .fd = fd,
-                .events = POLLIN,
-        };
         int count = 0;
 
         /* Read from the specified file descriptor, until POLLIN is not set anymore, throwing away everything
@@ -27,22 +23,18 @@ int flush_fd(int fd) {
                 ssize_t l;
                 int r;
 
-                r = poll(&pollfd, 1, 0);
+                r = fd_wait_for_event(fd, POLLIN, 0);
                 if (r < 0) {
-                        if (errno == EINTR)
+                        if (r == -EINTR)
                                 continue;
 
-                        return -errno;
+                        return r;
                 }
                 if (r == 0)
                         return count;
 
-                if (pollfd.revents & POLLNVAL)
-                        return -EBADF;
-
                 l = read(fd, buf, sizeof(buf));
                 if (l < 0) {
-
                         if (errno == EINTR)
                                 continue;
 
@@ -158,24 +150,15 @@ int loop_write(int fd, const void *buf, size_t nbytes, bool do_poll) {
 }
 
 int pipe_eof(int fd) {
-        struct pollfd pollfd = {
-                .fd = fd,
-                .events = POLLIN|POLLHUP,
-        };
-
         int r;
 
-        r = poll(&pollfd, 1, 0);
+        r = fd_wait_for_event(fd, POLLIN, 0);
         if (r < 0)
-                return -errno;
-
+                return r;
         if (r == 0)
                 return 0;
 
-        if (pollfd.revents & POLLNVAL)
-                return -EBADF;
-
-        return pollfd.revents & POLLHUP;
+        return !!(r & POLLHUP);
 }
 
 int fd_wait_for_event(int fd, int event, usec_t t) {
diff --git a/src/basic/socket-util.c b/src/basic/socket-util.c
index 2c990047fc..07f534f34d 100644
--- a/src/basic/socket-util.c
+++ b/src/basic/socket-util.c
@@ -21,6 +21,7 @@
 #include "fd-util.h"
 #include "fileio.h"
 #include "format-util.h"
+#include "io-util.h"
 #include "log.h"
 #include "macro.h"
 #include "memory-util.h"
@@ -968,10 +969,6 @@ fallback:
 
 int flush_accept(int fd) {
 
-        struct pollfd pollfd = {
-                .fd = fd,
-                .events = POLLIN,
-        };
         int r, b;
         socklen_t l = sizeof(b);
 
@@ -992,19 +989,16 @@ int flush_accept(int fd) {
         for (unsigned iteration = 0;; iteration++) {
                 int cfd;
 
-                r = poll(&pollfd, 1, 0);
+                r = fd_wait_for_event(fd, POLLIN, 0);
                 if (r < 0) {
-                        if (errno == EINTR)
+                        if (r == -EINTR)
                                 continue;
 
-                        return -errno;
+                        return r;
                 }
                 if (r == 0)
                         return 0;
 
-                if (pollfd.revents & POLLNVAL)
-                        return -EBADF;
-
                 if (iteration >= MAX_FLUSH_ITERATIONS)
                         return log_debug_errno(SYNTHETIC_ERRNO(EBUSY),
                                                "Failed to flush connections within " STRINGIFY(MAX_FLUSH_ITERATIONS) " iterations.");
diff --git a/src/libsystemd/sd-bus/bus-socket.c b/src/libsystemd/sd-bus/bus-socket.c
index 778f80377f..fc7e8e844a 100644
--- a/src/libsystemd/sd-bus/bus-socket.c
+++ b/src/libsystemd/sd-bus/bus-socket.c
@@ -1262,23 +1262,15 @@ int bus_socket_read_message(sd_bus *bus) {
 }
 
 int bus_socket_process_opening(sd_bus *b) {
-        int error = 0;
+        int error = 0, events, r;
         socklen_t slen = sizeof(error);
-        struct pollfd p = {
-                .fd = b->output_fd,
-                .events = POLLOUT,
-        };
-        int r;
 
         assert(b->state == BUS_OPENING);
 
-        r = poll(&p, 1, 0);
-        if (r < 0)
-                return -errno;
-        if (p.revents & POLLNVAL)
-                return -EBADF;
-
-        if (!(p.revents & (POLLOUT|POLLERR|POLLHUP)))
+        events = fd_wait_for_event(b->output_fd, POLLOUT, 0);
+        if (events < 0)
+                return events;
+        if (!(events & (POLLOUT|POLLERR|POLLHUP)))
                 return 0;
 
         r = getsockopt(b->output_fd, SOL_SOCKET, SO_ERROR, &error, &slen);
@@ -1286,7 +1278,7 @@ int bus_socket_process_opening(sd_bus *b) {
                 b->last_connect_error = errno;
         else if (error != 0)
                 b->last_connect_error = error;
-        else if (p.revents & (POLLERR|POLLHUP))
+        else if (events & (POLLERR|POLLHUP))
                 b->last_connect_error = ECONNREFUSED;
         else
                 return bus_socket_start_auth(b);
diff --git a/src/libsystemd/sd-daemon/sd-daemon.c b/src/libsystemd/sd-daemon/sd-daemon.c
index 0bc0fc16ae..bbe7cd76d5 100644
--- a/src/libsystemd/sd-daemon/sd-daemon.c
+++ b/src/libsystemd/sd-daemon/sd-daemon.c
@@ -555,7 +555,6 @@ finish:
 
 _public_ int sd_notify_barrier(int unset_environment, uint64_t timeout) {
         _cleanup_close_pair_ int pipe_fd[2] = { -1, -1 };
-        struct timespec ts;
         int r;
 
         if (pipe2(pipe_fd, O_CLOEXEC) < 0)
@@ -567,18 +566,11 @@ _public_ int sd_notify_barrier(int unset_environment, uint64_t timeout) {
 
         pipe_fd[1] = safe_close(pipe_fd[1]);
 
-        struct pollfd pfd = {
-                .fd = pipe_fd[0],
-                /* POLLHUP is implicit */
-                .events = 0,
-        };
-        r = ppoll(&pfd, 1, timeout == UINT64_MAX ? NULL : timespec_store(&ts, timeout), NULL);
+        r = fd_wait_for_event(pipe_fd[0], 0 /* POLLHUP is implicit */, timeout);
         if (r < 0)
-                return -errno;
+                return r;
         if (r == 0)
                 return -ETIMEDOUT;
-        if (pfd.revents & POLLNVAL)
-                return -EBADF;
 
         return 1;
 }
diff --git a/src/libsystemd/sd-netlink/sd-netlink.c b/src/libsystemd/sd-netlink/sd-netlink.c
index ddeb4a7992..91670ee324 100644
--- a/src/libsystemd/sd-netlink/sd-netlink.c
+++ b/src/libsystemd/sd-netlink/sd-netlink.c
@@ -7,6 +7,7 @@
 #include "alloc-util.h"
 #include "fd-util.h"
 #include "hashmap.h"
+#include "io-util.h"
 #include "macro.h"
 #include "netlink-internal.h"
 #include "netlink-slot.h"
@@ -462,7 +463,6 @@ static usec_t calc_elapse(uint64_t usec) {
 }
 
 static int rtnl_poll(sd_netlink *rtnl, bool need_more, uint64_t timeout_usec) {
-        struct timespec ts;
         usec_t m = USEC_INFINITY;
         int r, e;
 
@@ -491,23 +491,15 @@ static int rtnl_poll(sd_netlink *rtnl, bool need_more, uint64_t timeout_usec) {
                 }
         }
 
-        if (timeout_usec != (uint64_t) -1 && (m == (uint64_t) -1 || timeout_usec < m))
+        if (timeout_usec != (uint64_t) -1 && (m == USEC_INFINITY || timeout_usec < m))
                 m = timeout_usec;
 
-        struct pollfd p = {
-                .fd = rtnl->fd,
-                .events = e,
-        };
-
-        r = ppoll(&p, 1, m == (uint64_t) -1 ? NULL : timespec_store(&ts, m), NULL);
+        r = fd_wait_for_event(rtnl->fd, e, m);
         if (r < 0)
-                return -errno;
+                return r;
         if (r == 0)
                 return 0;
 
-        if (p.revents & POLLNVAL)
-                return -EBADF;
-
         return 1;
 }
 
diff --git a/src/libudev/libudev-monitor.c b/src/libudev/libudev-monitor.c
index bf23021b53..5bec7418b8 100644
--- a/src/libudev/libudev-monitor.c
+++ b/src/libudev/libudev-monitor.c
@@ -9,6 +9,7 @@
 #include "device-monitor-private.h"
 #include "device-private.h"
 #include "device-util.h"
+#include "io-util.h"
 #include "libudev-device-internal.h"
 #include "string-util.h"
 
@@ -191,17 +192,11 @@ _public_ int udev_monitor_get_fd(struct udev_monitor *udev_monitor) {
 }
 
 static int udev_monitor_receive_sd_device(struct udev_monitor *udev_monitor, sd_device **ret) {
-        struct pollfd pfd;
         int r;
 
         assert(udev_monitor);
         assert(ret);
 
-        pfd = (struct pollfd) {
-                .fd = device_monitor_get_fd(udev_monitor->monitor),
-                .events = POLLIN,
-        };
-
         for (;;) {
                 /* r == 0 means a device is received but it does not pass the current filter. */
                 r = device_monitor_receive_device(udev_monitor->monitor, ret);
@@ -209,20 +204,18 @@ static int udev_monitor_receive_sd_device(struct udev_monitor *udev_monitor, sd_
                         return r;
 
                 for (;;) {
-                        /* wait next message */
-                        r = poll(&pfd, 1, 0);
+                        /* Wait for next message */
+                        r = fd_wait_for_event(device_monitor_get_fd(udev_monitor->monitor), POLLIN, 0);
                         if (r < 0) {
-                                if (IN_SET(errno, EINTR, EAGAIN))
+                                if (IN_SET(r, -EINTR, -EAGAIN))
                                         continue;
 
-                                return -errno;
+                                return r;
                         }
                         if (r == 0)
                                 return -EAGAIN;
-                        if (pfd.revents & POLLNVAL)
-                                return -EBADF;
 
-                        /* receive next message */
+                        /* Receive next message */
                         break;
                 }
         }
diff --git a/src/shared/utmp-wtmp.c b/src/shared/utmp-wtmp.c
index 7d0d90247c..9debb54390 100644
--- a/src/shared/utmp-wtmp.c
+++ b/src/shared/utmp-wtmp.c
@@ -14,6 +14,7 @@
 #include "alloc-util.h"
 #include "fd-util.h"
 #include "hostname-util.h"
+#include "io-util.h"
 #include "macro.h"
 #include "memory-util.h"
 #include "path-util.h"
@@ -297,7 +298,7 @@ int utmp_put_runlevel(int runlevel, int previous) {
         return write_entry_both(&store);
 }
 
-#define TIMEOUT_MSEC 50
+#define TIMEOUT_USEC (50 * USEC_PER_MSEC)
 
 static int write_to_terminal(const char *tty, const char *message) {
         _cleanup_close_ int fd = -1;
@@ -315,14 +316,10 @@ static int write_to_terminal(const char *tty, const char *message) {
         p = message;
         left = strlen(message);
 
-        end = now(CLOCK_MONOTONIC) + TIMEOUT_MSEC*USEC_PER_MSEC;
+        end = now(CLOCK_MONOTONIC) + TIMEOUT_USEC;
 
         while (left > 0) {
                 ssize_t n;
-                struct pollfd pollfd = {
-                        .fd = fd,
-                        .events = POLLOUT,
-                };
                 usec_t t;
                 int k;
 
@@ -331,13 +328,11 @@ static int write_to_terminal(const char *tty, const char *message) {
                 if (t >= end)
                         return -ETIME;
 
-                k = poll(&pollfd, 1, (end - t) / USEC_PER_MSEC);
+                k = fd_wait_for_event(fd, POLLOUT, end - t);
                 if (k < 0)
-                        return -errno;
+                        return k;
                 if (k == 0)
                         return -ETIME;
-                if (pollfd.revents & POLLNVAL)
-                        return -EBADF;
 
                 n = write(fd, p, left);
                 if (n < 0) {
diff --git a/src/shared/varlink.c b/src/shared/varlink.c
index c0b5874225..1f4d5a614c 100644
--- a/src/shared/varlink.c
+++ b/src/shared/varlink.c
@@ -6,6 +6,7 @@
 #include "errno-util.h"
 #include "fd-util.h"
 #include "hashmap.h"
+#include "io-util.h"
 #include "list.h"
 #include "process-util.h"
 #include "set.h"
@@ -1003,8 +1004,6 @@ static void handle_revents(Varlink *v, int revents) {
 }
 
 int varlink_wait(Varlink *v, usec_t timeout) {
-        struct timespec ts;
-        struct pollfd pfd;
         int r, fd, events;
         usec_t t;
 
@@ -1038,23 +1037,13 @@ int varlink_wait(Varlink *v, usec_t timeout) {
         if (events < 0)
                 return events;
 
-        pfd = (struct pollfd) {
-                .fd = fd,
-                .events = events,
-        };
-
-        r = ppoll(&pfd, 1,
-                  t == USEC_INFINITY ? NULL : timespec_store(&ts, t),
-                  NULL);
+        r = fd_wait_for_event(fd, events, t);
         if (r < 0)
-                return -errno;
+                return r;
         if (r == 0)
                 return 0;
 
-        if (pfd.revents & POLLNVAL)
-                return -EBADF;
-
-        handle_revents(v, pfd.revents);
+        handle_revents(v, r);
         return 1;
 }
 
@@ -1123,8 +1112,6 @@ int varlink_flush(Varlink *v) {
                 return -ENOTCONN;
 
         for (;;) {
-                struct pollfd pfd;
-
                 if (v->output_buffer_size == 0)
                         break;
                 if (v->write_disconnected)
@@ -1138,20 +1125,13 @@ int varlink_flush(Varlink *v) {
                         continue;
                 }
 
-                pfd = (struct pollfd) {
-                        .fd = v->fd,
-                        .events = POLLOUT,
-                };
-
-                r = poll(&pfd, 1, -1);
+                r = fd_wait_for_event(v->fd, POLLOUT, USEC_INFINITY);
                 if (r < 0)
-                        return -errno;
+                        return r;
 
-                assert(r > 0);
-                if (pfd.revents & POLLNVAL)
-                        return -EBADF;
+                assert(r != 0);
 
-                handle_revents(v, pfd.revents);
+                handle_revents(v, r);
         }
 
         return ret;
diff --git a/src/sleep/sleep.c b/src/sleep/sleep.c
index 4f9c23099a..11c51fb32b 100644
--- a/src/sleep/sleep.c
+++ b/src/sleep/sleep.c
@@ -23,6 +23,7 @@
 #include "fd-util.h"
 #include "fileio.h"
 #include "format-util.h"
+#include "io-util.h"
 #include "log.h"
 #include "main-func.h"
 #include "parse-util.h"
@@ -239,7 +240,6 @@ static int execute_s2h(const SleepConfig *sleep_config) {
         _cleanup_close_ int tfd = -1;
         char buf[FORMAT_TIMESPAN_MAX];
         struct itimerspec ts = {};
-        struct pollfd fds;
         int r;
 
         assert(sleep_config);
@@ -261,34 +261,25 @@ static int execute_s2h(const SleepConfig *sleep_config) {
         if (r < 0)
                 return r;
 
-        fds = (struct pollfd) {
-                .fd = tfd,
-                .events = POLLIN,
-        };
-        r = poll(&fds, 1, 0);
+        r = fd_wait_for_event(tfd, POLLIN, 0);
         if (r < 0)
-                return log_error_errno(errno, "Error polling timerfd: %m");
+                return log_error_errno(r, "Error polling timerfd: %m");
+        if (!FLAGS_SET(r, POLLIN)) /* We woke up before the alarm time, we are done. */
+                return 0;
 
         tfd = safe_close(tfd);
 
-        if (FLAGS_SET(fds.revents, POLLNVAL))
-                return log_error_errno(SYNTHETIC_ERRNO(EBADF), "Invalid timer fd to sleep on?");
-
-        if (!FLAGS_SET(fds.revents, POLLIN)) /* We woke up before the alarm time, we are done. */
-                return 0;
-
         /* If woken up after alarm time, hibernate */
         log_debug("Attempting to hibernate after waking from %s timer",
                   format_timespan(buf, sizeof(buf), sleep_config->hibernate_delay_sec, USEC_PER_SEC));
 
         r = execute(sleep_config->hibernate_modes, sleep_config->hibernate_states);
         if (r < 0) {
-                log_notice("Couldn't hibernate, will try to suspend again.");
+                log_notice_errno(r, "Couldn't hibernate, will try to suspend again.");
+
                 r = execute(sleep_config->suspend_modes, sleep_config->suspend_states);
-                if (r < 0) {
-                        log_notice("Could neither hibernate nor suspend again, giving up.");
-                        return r;
-                }
+                if (r < 0)
+                        return log_notice_errno(r, "Could neither hibernate nor suspend again, giving up.");
         }
 
         return 0;
diff --git a/src/udev/udevadm-settle.c b/src/udev/udevadm-settle.c
index 1fa267c831..5730349ba5 100644
--- a/src/udev/udevadm-settle.c
+++ b/src/udev/udevadm-settle.c
@@ -15,6 +15,7 @@
 #include "sd-bus.h"
 #include "sd-login.h"
 
+#include "io-util.h"
 #include "libudev-util.h"
 #include "string-util.h"
 #include "strv.h"
@@ -141,9 +142,8 @@ static int emit_deprecation_warning(void) {
 
 int settle_main(int argc, char *argv[], void *userdata) {
         _cleanup_(udev_queue_unrefp) struct udev_queue *queue = NULL;
-        struct pollfd pfd;
         usec_t deadline;
-        int r;
+        int r, fd;
 
         r = parse_argv(argc, argv);
         if (r <= 0)
@@ -177,17 +177,12 @@ int settle_main(int argc, char *argv[], void *userdata) {
         if (!queue)
                 return log_error_errno(errno, "Failed to get udev queue: %m");
 
-        r = udev_queue_get_fd(queue);
-        if (r < 0) {
-                log_debug_errno(r, "Queue is empty, nothing to watch.");
+        fd = udev_queue_get_fd(queue);
+        if (fd < 0) {
+                log_debug_errno(fd, "Queue is empty, nothing to watch: %m");
                 return 0;
         }
 
-        pfd = (struct pollfd) {
-                .events = POLLIN,
-                .fd = r,
-        };
-
         (void) emit_deprecation_warning();
 
         for (;;) {
@@ -202,12 +197,10 @@ int settle_main(int argc, char *argv[], void *userdata) {
                         return -ETIMEDOUT;
 
                 /* wake up when queue becomes empty */
-                r = poll(&pfd, 1, MSEC_PER_SEC);
+                r = fd_wait_for_event(fd, POLLIN, MSEC_PER_SEC);
                 if (r < 0)
-                        return -errno;
-                if (pfd.revents & POLLNVAL)
-                        return -EBADF;
-                if (r > 0 && pfd.revents & POLLIN) {
+                        return r;
+                if (r & POLLIN) {
                         r = udev_queue_flush(queue);
                         if (r < 0)
                                 return log_error_errno(r, "Failed to flush queue: %m");
diff --git a/src/userdb/userwork.c b/src/userdb/userwork.c
index 4a8c98384d..732063f6c7 100644
--- a/src/userdb/userwork.c
+++ b/src/userdb/userwork.c
@@ -9,6 +9,7 @@
 #include "fd-util.h"
 #include "group-record-nss.h"
 #include "group-record.h"
+#include "io-util.h"
 #include "main-func.h"
 #include "process-util.h"
 #include "strv.h"
@@ -747,20 +748,14 @@ static int run(int argc, char *argv[]) {
                         return log_error_errno(fd, "Failed to accept() from listening socket: %m");
 
                 if (now(CLOCK_MONOTONIC) <= usec_add(n, PRESSURE_SLEEP_TIME_USEC)) {
-                        struct pollfd pfd = {
-                                .fd = listen_fd,
-                                .events = POLLIN,
-                        };
-
                         /* We only slept a very short time? If so, let's see if there are more sockets
                          * pending, and if so, let's ask our parent for more workers */
 
-                        if (poll(&pfd, 1, 0) < 0)
-                                return log_error_errno(errno, "Failed to test for POLLIN on listening socket: %m");
-                        if (FLAGS_SET(pfd.revents, POLLNVAL))
-                                return log_error_errno(SYNTHETIC_ERRNO(EBADF), "Listening socket dead?");
+                        r = fd_wait_for_event(listen_fd, POLLIN, 0);
+                        if (r < 0)
+                                return log_error_errno(r, "Failed to test for POLLIN on listening socket: %m");
 
-                        if (FLAGS_SET(pfd.revents, POLLIN)) {
+                        if (FLAGS_SET(r, POLLIN)) {
                                 pid_t parent;
 
                                 parent = getppid();