From f7c1ad4fd4190bee32db0aa26c8e9fe7e19d8816 Mon Sep 17 00:00:00 2001
From: Lennart Poettering <lennart@poettering.net>
Date: Wed, 10 Dec 2014 01:45:43 +0100
Subject: core: unify how we iterate over inotify events

Let's add some syntactic sugar for iterating through inotify events, and
use it everywhere.
---
 src/core/mount.c | 48 ++++++++++++++++++++++++++++++------------------
 src/core/path.c  | 32 ++++++++------------------------
 2 files changed, 38 insertions(+), 42 deletions(-)

(limited to 'src/core')

diff --git a/src/core/mount.c b/src/core/mount.c
index 5f268c6ddc..66de85b578 100644
--- a/src/core/mount.c
+++ b/src/core/mount.c
@@ -1616,14 +1616,18 @@ static int mount_enumerate(Manager *m) {
 
         if (m->utab_inotify_fd < 0) {
                 m->utab_inotify_fd = inotify_init1(IN_NONBLOCK|IN_CLOEXEC);
-                if (m->utab_inotify_fd < 0)
-                        goto fail_with_errno;
+                if (m->utab_inotify_fd < 0) {
+                        r = -errno;
+                        goto fail;
+                }
 
                 (void) mkdir_p_label("/run/mount", 0755);
 
                 r = inotify_add_watch(m->utab_inotify_fd, "/run/mount", IN_MOVED_TO);
-                if (r < 0)
-                        goto fail_with_errno;
+                if (r < 0) {
+                        r = -errno;
+                        goto fail;
+                }
 
                 r = sd_event_add_io(m->event, &m->mount_utab_event_source, m->utab_inotify_fd, EPOLLIN, mount_dispatch_io, m);
                 if (r < 0)
@@ -1640,8 +1644,6 @@ static int mount_enumerate(Manager *m) {
 
         return 0;
 
-fail_with_errno:
-        r = -errno;
 fail:
         mount_shutdown(m);
         return r;
@@ -1661,22 +1663,32 @@ static int mount_dispatch_io(sd_event_source *source, int fd, uint32_t revents,
          * for mount options. */
 
         if (fd == m->utab_inotify_fd) {
-                char inotify_buffer[sizeof(struct inotify_event) + NAME_MAX + 1];
-                struct inotify_event *event;
-                char *p;
                 bool rescan = false;
 
-                while ((r = read(fd, inotify_buffer, sizeof(inotify_buffer))) > 0)
-                        for (p = inotify_buffer; p < inotify_buffer + r; ) {
-                                event = (struct inotify_event *) p;
-                                /* only care about changes to utab, but we have
-                                 * to monitor the directory to reliably get
-                                 * notifications about when utab is replaced
-                                 * using rename(2) */
-                                if ((event->mask & IN_Q_OVERFLOW) || streq(event->name, "utab"))
+                for (;;) {
+                        uint8_t buffer[INOTIFY_EVENT_MAX] _alignas_(struct inotify_event);
+                        struct inotify_event *e;
+                        ssize_t l;
+
+                        l = read(fd, buffer, sizeof(buffer));
+                        if (l < 0) {
+                                if (errno == EAGAIN || errno == EINTR)
+                                        break;
+
+                                log_error_errno(errno, "Failed to read utab inotify: %m");
+                                break;
+                        }
+
+                        FOREACH_INOTIFY_EVENT(e, buffer, l) {
+                                /* Only care about changes to utab,
+                                 * but we have to monitor the
+                                 * directory to reliably get
+                                 * notifications about when utab is
+                                 * replaced using rename(2) */
+                                if ((e->mask & IN_Q_OVERFLOW) || streq(e->name, "utab"))
                                         rescan = true;
-                                p += sizeof(struct inotify_event) + event->len;
                         }
+                }
 
                 if (!rescan)
                         return 0;
diff --git a/src/core/path.c b/src/core/path.c
index 3624bfcac7..656ed6941d 100644
--- a/src/core/path.c
+++ b/src/core/path.c
@@ -157,10 +157,9 @@ void path_spec_unwatch(PathSpec *s) {
 }
 
 int path_spec_fd_event(PathSpec *s, uint32_t revents) {
-        _cleanup_free_ uint8_t *buf = NULL;
+        uint8_t buffer[INOTIFY_EVENT_MAX] _alignas_(struct inotify_event);
         struct inotify_event *e;
-        ssize_t k;
-        int l;
+        ssize_t l;
         int r = 0;
 
         if (revents != EPOLLIN) {
@@ -168,33 +167,18 @@ int path_spec_fd_event(PathSpec *s, uint32_t revents) {
                 return -EINVAL;
         }
 
-        if (ioctl(s->inotify_fd, FIONREAD, &l) < 0)
-                return log_error_errno(errno, "FIONREAD failed: %m");
+        l = read(s->inotify_fd, buffer, sizeof(buffer));
+        if (l < 0) {
+                if (errno == EAGAIN || errno == EINTR)
+                        return 0;
 
-        assert(l > 0);
-
-        buf = malloc(l);
-        if (!buf)
-                return log_oom();
-
-        k = read(s->inotify_fd, buf, l);
-        if (k < 0)
                 return log_error_errno(errno, "Failed to read inotify event: %m");
+        }
 
-        e = (struct inotify_event*) buf;
-
-        while (k > 0) {
-                size_t step;
-
+        FOREACH_INOTIFY_EVENT(e, buffer, l) {
                 if ((s->type == PATH_CHANGED || s->type == PATH_MODIFIED) &&
                     s->primary_wd == e->wd)
                         r = 1;
-
-                step = sizeof(struct inotify_event) + e->len;
-                assert(step <= (size_t) k);
-
-                e = (struct inotify_event*) ((uint8_t*) e + step);
-                k -= step;
         }
 
         return r;
-- 
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