xwayland-shm: fortify fallocate against EINTR

If posix_fallocate or ftruncate is interrupted by signal while working,
we return -1 as fd and the allocation process returns BadAlloc error.
That causes xwayland clients to abort with 'BadAlloc (insufficient
resources for operation)' even when there's a lot of resources
available.

Fix it by trying again when we get EINTR.

Signed-off-by: Marek Chalupa <mchqwerty@gmail.com>
Reviewed-by: Pekka Paalanen <pekka.paalanen@collabora.co.uk>

1 files changed, 8 insertions, 2 deletions

diff --git a/hw/xwayland/xwayland-shm.c b/hw/xwayland/xwayland-shm.c
index e8545b3be..c199e5efb 100644
--- a/hw/xwayland/xwayland-shm.c
+++ b/hw/xwayland/xwayland-shm.c
@@ -140,14 +140,20 @@ os_create_anonymous_file(off_t size)
         return -1;
 
 #ifdef HAVE_POSIX_FALLOCATE
-    ret = posix_fallocate(fd, 0, size);
+    do {
+        ret = posix_fallocate(fd, 0, size);
+    } while (ret == EINTR);
+
     if (ret != 0) {
         close(fd);
         errno = ret;
         return -1;
     }
 #else
-    ret = ftruncate(fd, size);
+    do {
+        ret = ftruncate(fd, size);
+    } while (ret == -1 && errno == EINTR);
+
     if (ret < 0) {
         close(fd);
         return -1;