util: fix strict aliasing violations in use of struct inotify_event v5

There is alot of cleanup that will have to happen to turn on
-fstrict-aliasing, but I think our code should be "correct" to the rule.

2 files changed, 10 insertions, 5 deletions

diff --git a/src/shared/util.c b/src/shared/util.c
index 97ff320bc8..e95f6ed247 100644
--- a/src/shared/util.c
+++ b/src/shared/util.c
@@ -39,7 +39,6 @@
 #include <linux/tiocl.h>
 #include <termios.h>
 #include <stdarg.h>
-#include <sys/inotify.h>
 #include <sys/poll.h>
 #include <ctype.h>
 #include <sys/prctl.h>
@@ -2106,7 +2105,7 @@ int acquire_terminal(
                 assert(notify >= 0);
 
                 for (;;) {
-                        uint8_t buffer[INOTIFY_EVENT_MAX] _alignas_(struct inotify_event);
+                        union inotify_event_buffer buffer;
                         struct inotify_event *e;
                         ssize_t l;
 
@@ -2129,7 +2128,7 @@ int acquire_terminal(
                                 }
                         }
 
-                        l = read(notify, buffer, sizeof(buffer));
+                        l = read(notify, &buffer, sizeof(buffer));
                         if (l < 0) {
                                 if (errno == EINTR || errno == EAGAIN)
                                         continue;
diff --git a/src/shared/util.h b/src/shared/util.h
index ec0a6639ca..7f02f42c61 100644
--- a/src/shared/util.h
+++ b/src/shared/util.h
@@ -42,6 +42,7 @@
 #include <locale.h>
 #include <mntent.h>
 #include <sys/socket.h>
+#include <sys/inotify.h>
 
 #if SIZEOF_PID_T == 4
 #  define PID_FMT "%" PRIu32
@@ -1047,10 +1048,15 @@ int sethostname_idempotent(const char *s);
 #define INOTIFY_EVENT_MAX (sizeof(struct inotify_event) + NAME_MAX + 1)
 
 #define FOREACH_INOTIFY_EVENT(e, buffer, sz) \
-        for ((e) = (struct inotify_event*) (buffer);    \
-             (uint8_t*) (e) < (uint8_t*) (buffer) + (sz); \
+        for ((e) = &buffer.ev;                                \
+             (uint8_t*) (e) < (uint8_t*) (buffer.raw) + (sz); \
              (e) = (struct inotify_event*) ((uint8_t*) (e) + sizeof(struct inotify_event) + (e)->len))
 
+union inotify_event_buffer {
+        struct inotify_event ev;
+        uint8_t raw[INOTIFY_EVENT_MAX];
+};
+
 #define laccess(path, mode) faccessat(AT_FDCWD, (path), (mode), AT_SYMLINK_NOFOLLOW)
 
 int ptsname_malloc(int fd, char **ret);