0a3881d4cf
"git-index-pack --fix-thin" relies on mmap() not changing the current file position (otherwise the pack will be corrupted when writing the final SHA1). Meet that expectation. Signed-off-by: Johannes Schindelin <Johannes.Schindelin@gmx.de> Signed-off-by: Junio C Hamano <junkio@cox.net>
57 lines
957 B
C
57 lines
957 B
C
#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <errno.h>
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#include "../git-compat-util.h"
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void *gitfakemmap(void *start, size_t length, int prot , int flags, int fd, off_t offset)
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{
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int n = 0;
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off_t current_offset = lseek(fd, 0, SEEK_CUR);
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if (start != NULL || !(flags & MAP_PRIVATE))
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die("Invalid usage of gitfakemmap.");
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if (lseek(fd, offset, SEEK_SET) < 0) {
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errno = EINVAL;
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return MAP_FAILED;
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}
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start = xmalloc(length);
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if (start == NULL) {
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errno = ENOMEM;
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return MAP_FAILED;
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}
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while (n < length) {
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int count = read(fd, start+n, length-n);
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if (count == 0) {
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memset(start+n, 0, length-n);
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break;
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}
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if (count < 0) {
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free(start);
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errno = EACCES;
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return MAP_FAILED;
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}
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n += count;
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}
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if (current_offset != lseek(fd, current_offset, SEEK_SET)) {
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errno = EINVAL;
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return MAP_FAILED;
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}
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return start;
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}
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int gitfakemunmap(void *start, size_t length)
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{
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free(start);
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return 0;
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}
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