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bsd-user: Handle short reads in mmap_h_gt_g
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> Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org> Message-Id: <20240820050848.165253-3-richard.henderson@linaro.org>
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@ -128,6 +128,40 @@ error:
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return ret;
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}
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/*
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* Perform a pread on behalf of target_mmap. We can reach EOF, we can be
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* interrupted by signals, and in general there's no good error return path.
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* If @zero, zero the rest of the block at EOF.
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* Return true on success.
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*/
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static bool mmap_pread(int fd, void *p, size_t len, off_t offset, bool zero)
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{
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while (1) {
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ssize_t r = pread(fd, p, len, offset);
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if (likely(r == len)) {
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/* Complete */
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return true;
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}
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if (r == 0) {
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/* EOF */
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if (zero) {
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memset(p, 0, len);
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}
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return true;
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}
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if (r > 0) {
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/* Short read */
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p += r;
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len -= r;
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offset += r;
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} else if (errno != EINTR) {
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/* Error */
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return false;
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}
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}
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}
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/*
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* map an incomplete host page
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*
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@ -190,7 +224,7 @@ static int mmap_frag(abi_ulong real_start,
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mprotect(host_start, qemu_host_page_size, prot1 | PROT_WRITE);
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/* read the corresponding file data */
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if (pread(fd, g2h_untagged(start), end - start, offset) == -1) {
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if (!mmap_pread(fd, g2h_untagged(start), end - start, offset, true)) {
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return -1;
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}
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@ -565,7 +599,7 @@ abi_long target_mmap(abi_ulong start, abi_ulong len, int prot,
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-1, 0);
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if (retaddr == -1)
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goto fail;
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if (pread(fd, g2h_untagged(start), len, offset) == -1) {
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if (!mmap_pread(fd, g2h_untagged(start), len, offset, false)) {
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goto fail;
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}
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if (!(prot & PROT_WRITE)) {
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