@@ -282,6 +282,40 @@ static int do_munmap(void *addr, size_t len)
return munmap(addr, len);
}
+/*
+ * Perform a pread on behalf of target_mmap. We can reach EOF, we can be
+ * interrupted by signals, and in general there's no good error return path.
+ * If @zero, zero the rest of the block at EOF.
+ * Return true on success.
+ */
+static bool mmap_pread(int fd, void *p, size_t len, off_t offset, bool zero)
+{
+ while (1) {
+ ssize_t r = pread(fd, p, len, offset);
+
+ if (likely(r == len)) {
+ /* Complete */
+ return true;
+ }
+ if (r == 0) {
+ /* EOF */
+ if (zero) {
+ memset(p, 0, len);
+ }
+ return true;
+ }
+ if (r > 0) {
+ /* Short read */
+ p += r;
+ len -= r;
+ offset += r;
+ } else if (errno != EINTR) {
+ /* Error */
+ return false;
+ }
+ }
+}
+
/*
* Map an incomplete host page.
*
@@ -356,10 +390,9 @@ static bool mmap_frag(abi_ulong real_start, abi_ulong start, abi_ulong last,
/* Read or zero the new guest pages. */
if (flags & MAP_ANONYMOUS) {
memset(g2h_untagged(start), 0, last - start + 1);
- } else {
- if (pread(fd, g2h_untagged(start), last - start + 1, offset) == -1) {
- return false;
- }
+ } else if (!mmap_pread(fd, g2h_untagged(start), last - start + 1,
+ offset, true)) {
+ return false;
}
/* Put final protection */
@@ -852,8 +885,7 @@ static abi_long mmap_h_gt_g(abi_ulong start, abi_ulong len,
}
if (misaligned_offset) {
- /* TODO: The read could be short. */
- if (pread(fd, p, host_len, offset + real_start - start) != host_len) {
+ if (!mmap_pread(fd, p, host_len, offset + real_start - start, false)) {
do_munmap(p, host_len);
return -1;
}