Commit a9f57a8919f264fa184320d1f5c3ed7a35b7576a
2020-11-23T10:14:00
Remove broken support for write in emulated mmap * Emulated mmap based write without pagefault handling is not possible since IO happens outside of call to mmap and data is written to mapped memory * Potential emulation using userfaultfd() might be possible
diff --git a/src/posix.c b/src/posix.c
index 9cd96d2..debd8d2 100644
--- a/src/posix.c
+++ b/src/posix.c
@@ -240,14 +240,15 @@ int p_mmap(git_map *out, size_t len, int prot, int flags, int fd, off64_t offset
{
GIT_MMAP_VALIDATE(out, len, prot, flags);
- out->data = NULL;
- out->len = 0;
-
- if ((prot & GIT_PROT_WRITE) && ((flags & GIT_MAP_TYPE) == GIT_MAP_SHARED)) {
- git_error_set(GIT_ERROR_OS, "trying to map shared-writeable");
+ /* writes cannot be emulated without handling pagefaults since write happens by
+ * writing to mapped memory */
+ if (prot & GIT_PROT_WRITE) {
+ git_error_set(GIT_ERROR_OS, "trying to map %s-writeable",
+ ((flags & GIT_MAP_TYPE) == GIT_MAP_SHARED) ? "shared": "private");
return -1;
}
+ out->len = 0;
out->data = git__malloc(len);
GIT_ERROR_CHECK_ALLOC(out->data);