@@ -128,6 +128,40 @@ error:
return ret;
}
+/*
+ * 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
*
@@ -190,7 +224,7 @@ static int mmap_frag(abi_ulong real_start,
mprotect(host_start, qemu_host_page_size, prot1 | PROT_WRITE);
/* read the corresponding file data */
- if (pread(fd, g2h_untagged(start), end - start, offset) == -1) {
+ if (!mmap_pread(fd, g2h_untagged(start), end - start, offset, true)) {
return -1;
}
@@ -565,7 +599,7 @@ abi_long target_mmap(abi_ulong start, abi_ulong len, int prot,
-1, 0);
if (retaddr == -1)
goto fail;
- if (pread(fd, g2h_untagged(start), len, offset) == -1) {
+ if (!mmap_pread(fd, g2h_untagged(start), len, offset, false)) {
goto fail;
}
if (!(prot & PROT_WRITE)) {
In particular, if an image has a large bss, we can hit EOF before reading all bytes of the mapping. Mirror the similar change to linux-user. Signed-off-by: Richard Henderson <richard.henderson@linaro.org> --- bsd-user/mmap.c | 38 ++++++++++++++++++++++++++++++++++++-- 1 file changed, 36 insertions(+), 2 deletions(-)