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[PATCH v2 7/9] bsd-user/mmap.c: Don't mmap fd == -1 independently from M
From: |
Warner Losh |
Subject: |
[PATCH v2 7/9] bsd-user/mmap.c: Don't mmap fd == -1 independently from MAP_ANON flag |
Date: |
Tue, 21 Sep 2021 22:56:34 -0600 |
From: Guy Yur <guyyur@gmail.com>
Switch checks for !(flags & MAP_ANONYMOUS) with checks for fd != -1.
MAP_STACK and MAP_GUARD both require fd == -1 and don't require mapping
the fd either.
Signed-off-by: Guy Yur <guyyur@gmail.com>
[ partially merged before, finishing the job and documenting origin]
Signed-off-by: Warner Losh <imp@bsdimp.com>
---
bsd-user/mmap.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/bsd-user/mmap.c b/bsd-user/mmap.c
index 8b763fffc3..347d314aa9 100644
--- a/bsd-user/mmap.c
+++ b/bsd-user/mmap.c
@@ -154,7 +154,7 @@ static int mmap_frag(abi_ulong real_start,
if (prot1 == 0) {
/* no page was there, so we allocate one */
void *p = mmap(host_start, qemu_host_page_size, prot,
- flags | MAP_ANON, -1, 0);
+ flags | ((fd != -1) ? MAP_ANON : 0), -1, 0);
if (p == MAP_FAILED)
return -1;
prot1 = prot;
@@ -162,7 +162,7 @@ static int mmap_frag(abi_ulong real_start,
prot1 &= PAGE_BITS;
prot_new = prot | prot1;
- if (!(flags & MAP_ANON)) {
+ if (fd != -1) {
/* msync() won't work here, so we return an error if write is
possible while it is a shared mapping */
if ((flags & TARGET_BSD_MAP_FLAGMASK) == MAP_SHARED &&
@@ -571,7 +571,7 @@ abi_long target_mmap(abi_ulong start, abi_ulong len, int
prot,
* worst case: we cannot map the file because the offset is not
* aligned, so we read it
*/
- if (!(flags & MAP_ANON) &&
+ if (fd != -1 &&
(offset & ~qemu_host_page_mask) != (start & ~qemu_host_page_mask))
{
/*
* msync() won't work here, so we return an error if write is
--
2.32.0
- Re: [PATCH v2 4/9] bsd-user/mmap.c: mmap return ENOMEM on overflow, (continued)
[PATCH v2 9/9] bsd-user/mmap.c: assert that target_mprotect cannot fail, Warner Losh, 2021/09/22