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linux-user: Implement MAP_FIXED_NOREPLACE

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Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20230707204054.8792-12-richard.henderson@linaro.org>
This commit is contained in:
Richard Henderson 2023-07-07 21:40:39 +01:00
parent 9c255cb53e
commit 037986053b
1 changed files with 11 additions and 3 deletions
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14
linux-user/mmap.c
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@ -509,7 +509,7 @@ abi_long target_mmap(abi_ulong start, abi_ulong len, int target_prot,
* If the user is asking for the kernel to find a location, do that * If the user is asking for the kernel to find a location, do that
* before we truncate the length for mapping files below. * before we truncate the length for mapping files below.
*/ */
if (!(flags & MAP_FIXED)) { if (!(flags & (MAP_FIXED | MAP_FIXED_NOREPLACE))) {
host_len = len + offset - host_offset; host_len = len + offset - host_offset;
host_len = HOST_PAGE_ALIGN(host_len); host_len = HOST_PAGE_ALIGN(host_len);
start = mmap_find_vma(real_start, host_len, TARGET_PAGE_SIZE); start = mmap_find_vma(real_start, host_len, TARGET_PAGE_SIZE);
@ -551,7 +551,7 @@ abi_long target_mmap(abi_ulong start, abi_ulong len, int target_prot,
} }
} }
if (!(flags & MAP_FIXED)) { if (!(flags & (MAP_FIXED | MAP_FIXED_NOREPLACE))) {
unsigned long host_start; unsigned long host_start;
void *p; void *p;
@ -600,6 +600,13 @@ abi_long target_mmap(abi_ulong start, abi_ulong len, int target_prot,
goto fail; goto fail;
} }
/* Validate that the chosen range is empty. */
if ((flags & MAP_FIXED_NOREPLACE)
&& !page_check_range_empty(start, end - 1)) {
errno = EEXIST;
goto fail;
}
/* /*
* worst case: we cannot map the file because the offset is not * worst case: we cannot map the file because the offset is not
* aligned, so we read it * aligned, so we read it
@ -615,7 +622,8 @@ abi_long target_mmap(abi_ulong start, abi_ulong len, int target_prot,
goto fail; goto fail;
} }
retaddr = target_mmap(start, len, target_prot | PROT_WRITE, retaddr = target_mmap(start, len, target_prot | PROT_WRITE,
MAP_FIXED | MAP_PRIVATE | MAP_ANONYMOUS, (flags & (MAP_FIXED | MAP_FIXED_NOREPLACE))
| MAP_PRIVATE | MAP_ANONYMOUS,
-1, 0); -1, 0);
if (retaddr == -1) { if (retaddr == -1) {
goto fail; goto fail;