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xbps_file_hash: simplify and use read(2).

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This commit is contained in:
Juan RP 2013-11-26 13:08:44 +01:00
parent a30623c65c
commit 4e427ded92
1 changed files with 9 additions and 27 deletions
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36
lib/util_hash.c
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@ -23,10 +23,6 @@
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#define _BSD_SOURCE /* for madvise(2) */
#include <sys/mman.h>
#undef _BSD_SOURCE
#include <stdio.h>
#include <stdbool.h>
#include <stdlib.h>
@ -65,12 +61,9 @@ char *
xbps_file_hash(const char *file)
{
struct stat st;
size_t pgsize = (size_t)sysconf(_SC_PAGESIZE);
size_t pgmask = pgsize - 1, mapsize;
char hash[SHA256_DIGEST_LENGTH * 2 + 1];
unsigned char *buf = NULL, digest[SHA256_DIGEST_LENGTH];
int fd;
bool need_guard = false;
assert(file != NULL);
@ -88,31 +81,20 @@ xbps_file_hash(const char *file)
return NULL;
}
mapsize = ((size_t)st.st_size + pgmask) & ~pgmask;
if (mapsize < (size_t)st.st_size) {
(void)close(fd);
return NULL;
}
/*
* If the file length is an integral number of pages, then we
* need to map a guard page at the end in order to provide the
* necessary NUL-termination of the buffer.
*/
if ((st.st_size & pgmask) == 0)
need_guard = true;
buf = malloc(st.st_size);
assert(buf);
buf = mmap(NULL, need_guard ? mapsize + pgsize : mapsize,
PROT_READ, MAP_PRIVATE, fd, 0);
if (read(fd, buf, st.st_size) != st.st_size) {
free(buf);
(void)close(fd);
return NULL;
}
(void)close(fd);
if (buf == MAP_FAILED)
return NULL;
if (SHA256(buf, st.st_size, digest) == NULL) {
munmap(buf, mapsize);
free(buf);
return NULL;
}
munmap(buf, mapsize);
free(buf);
digest2string(digest, hash, SHA256_DIGEST_LENGTH);
return strdup(hash);