git/compat/mmap.c
René Scharfe 95b4ff3931 compat: let git_mmap use malloc(3) directly
xmalloc() dies on error, allows zero-sized allocations and enforces
GIT_ALLOC_LIMIT for testing.  Our mmap replacement doesn't need any of
that.  Let's cut out the wrapper, reject zero-sized requests as required
by POSIX and use malloc(3) directly.  Allocation errors were needlessly
handled by git_mmap() before; this code becomes reachable now.

Signed-off-by: René Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-08-24 14:43:45 -07:00

45 lines
773 B
C

#include "../git-compat-util.h"
void *git_mmap(void *start, size_t length, int prot, int flags, int fd, off_t offset)
{
size_t n = 0;
if (start != NULL || flags != MAP_PRIVATE || prot != PROT_READ)
die("Invalid usage of mmap when built with NO_MMAP");
if (length == 0) {
errno = EINVAL;
return MAP_FAILED;
}
start = malloc(length);
if (start == NULL) {
errno = ENOMEM;
return MAP_FAILED;
}
while (n < length) {
ssize_t count = xpread(fd, (char *)start + n, length - n, offset + n);
if (count == 0) {
memset((char *)start+n, 0, length-n);
break;
}
if (count < 0) {
free(start);
errno = EACCES;
return MAP_FAILED;
}
n += count;
}
return start;
}
int git_munmap(void *start, size_t length)
{
free(start);
return 0;
}