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Yank writing-back support from gitfakemmap.
We do not write through our use of mmap(), so make sure callers pass MAP_PRIVATE and remove support for writing changes back. Signed-off-by: Junio C Hamano <junkio@cox.net>
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730d48a2ef
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@ -4,43 +4,33 @@
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#include <errno.h>
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#include "../cache.h"
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typedef struct fakemmapwritable {
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void *start;
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size_t length;
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int fd;
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off_t offset;
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struct fakemmapwritable *next;
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} fakemmapwritable;
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static fakemmapwritable *writablelist = NULL;
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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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if(start != NULL)
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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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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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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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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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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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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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@ -49,65 +39,12 @@ void *gitfakemmap(void *start, size_t length, int prot , int flags, int fd, off_
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n += count;
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}
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if(prot & PROT_WRITE) {
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fakemmapwritable *next = xmalloc(sizeof(fakemmapwritable));
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next->start = start;
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next->length = length;
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next->fd = dup(fd);
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next->offset = offset;
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next->next = writablelist;
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writablelist = next;
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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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fakemmapwritable *writable = writablelist, *before = NULL;
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while(writable && (writable->start > start + length
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|| writable->start + writable->length < start)) {
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before = writable;
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writable = writable->next;
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}
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if(writable) {
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/* need to write back the contents */
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int n = 0;
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if(writable->start != start || writable->length != length)
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die("fakemmap does not support partial write back.");
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if(lseek(writable->fd, writable->offset, SEEK_SET) < 0) {
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free(start);
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errno = EBADF;
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return -1;
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}
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while(n < length) {
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int count = write(writable->fd, start + n, length - n);
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if(count < 0) {
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errno = EINVAL;
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return -1;
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}
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n += count;
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}
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close(writable->fd);
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if(before)
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before->next = writable->next;
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else
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writablelist = writable->next;
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free(writable);
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}
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free(start);
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return 0;
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}
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