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--- src/wayland-shm.c.orig 2016-03-09 00:55:02 UTC
+++ src/wayland-shm.c
@@ -30,6 +30,8 @@
#define _GNU_SOURCE
+#include "../config.h"
+
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
@@ -57,6 +59,9 @@ struct wl_shm_pool {
char *data;
int32_t size;
int32_t new_size;
+#ifdef HAVE_SYS_UCRED_H
+ int fd;
+#endif
};
struct wl_shm_buffer {
@@ -74,15 +79,24 @@ struct wl_shm_sigbus_data {
int fallback_mapping_used;
};
+static void *mremap_compat_maymove(void *, size_t, size_t, int, int, int);
+
static void
shm_pool_finish_resize(struct wl_shm_pool *pool)
{
void *data;
+ int fd = -1;
if (pool->size == pool->new_size)
return;
- data = mremap(pool->data, pool->size, pool->new_size, MREMAP_MAYMOVE);
+#ifdef HAVE_SYS_UCRED_H
+ fd = pool->fd;
+#endif
+
+ data = mremap_compat_maymove(pool->data, pool->size, pool->new_size,
+ PROT_READ | PROT_WRITE, MAP_SHARED, fd);
+
if (data == MAP_FAILED) {
wl_resource_post_error(pool->resource,
WL_SHM_ERROR_INVALID_FD,
@@ -108,6 +122,10 @@ shm_pool_unref(struct wl_shm_pool *pool,
if (pool->internal_refcount + pool->external_refcount)
return;
+#ifdef HAVE_SYS_UCRED_H
+ close(pool->fd);
+#endif
+
munmap(pool->data, pool->size);
free(pool);
}
@@ -221,6 +239,73 @@ shm_pool_destroy(struct wl_client *clien
wl_resource_destroy(resource);
}
+#ifdef HAVE_MREMAP
+static void *
+mremap_compat_maymove(void *old_address, size_t old_size, size_t new_size,
+ int old_prot, int old_flags, int old_fd)
+{
+ return mremap(old_address, old_size, new_size, MREMAP_MAYMOVE);
+}
+#else
+static void *
+mremap_compat_maymove(void *old_address, size_t old_size, size_t new_size,
+ int old_prot, int old_flags, int old_fd)
+{
+ /* FreeBSD doesn't support mremap() yet, so we have to emulate it.
+ * This assumes MREMAP_MAYMOVE is the only flag in use. */
+ if (new_size == old_size) {
+ return old_address;
+ } else if (new_size < old_size) {
+ /* Shrinking: munmap() the spare region. */
+ munmap(old_address + old_size, new_size - old_size);
+ return old_address;
+ } else {
+ void *ret;
+
+ /* Growing. Try and mmap() the extra region at the end of
+ * our existing allocation. If that gets mapped in the
+ * wrong place, fall back to mmap()ing an entirely new
+ * region of new_size and copying the data across. */
+ ret = mmap(old_address + old_size, new_size - old_size,
+ old_prot, old_flags, old_fd, 0);
+
+/* FIXME TODO: msync() before munmap()? */
+ if (ret == MAP_FAILED) {
+ /* Total failure! */
+ return ret;
+ } else if (ret == old_address + old_size) {
+ /* Success. */
+ return old_address;
+ } else if (ret != old_address + old_size) {
+ /* Partial failure. Fall back to mapping an
+ * entirely new region. Unmap the region we
+ * just mapped first. */
+ munmap(ret, new_size - old_size);
+
+ /* Map an entirely new region. */
+ ret = mmap(NULL, new_size,
+ old_prot, old_flags, old_fd, 0);
+ if (ret == MAP_FAILED) {
+ /* Total failure! */
+ return ret;
+ }
+
+ /* Copy the old data across. Implicit assumption
+ * that the old and new regions don't overlap. */
+ memcpy(ret, old_address, old_size);
+
+ /* Unmap the old region. */
+ munmap(old_address, old_size);
+
+ return ret;
+ }
+ }
+
+ /* Unreachable. */
+ return MAP_FAILED;
+}
+#endif
+
static void
shm_pool_resize(struct wl_client *client, struct wl_resource *resource,
int32_t size)
@@ -282,7 +367,14 @@ shm_create_pool(struct wl_client *client
"failed mmap fd %d", fd);
goto err_free;
}
+
+#ifdef HAVE_SYS_UCRED_H
+ /* We need to keep the FD around on FreeBSD so we can implement
+ * mremap(). See: mremap_compat_maymove(). */
+ pool->fd = fd;
+#else
close(fd);
+#endif
pool->resource =
wl_resource_create(client, &wl_shm_pool_interface, 1, id);
|
