From 7ce66edc572eb3c47c890bfe3ce5d37cc2b0f346 Mon Sep 17 00:00:00 2001
From: Enno Boland <g@s01.de>
Date: Wed, 15 Jun 2016 23:21:29 +0200
Subject: [PATCH] lib/util_hash.c: add xbps_file_hash_raw method
this function does not mmap the target file and therefore
avoids out of memory exceptions on 32bit systems.
---
include/xbps.h.in | 11 +++++++++++
lib/util_hash.c | 33 ++++++++++++++++++++++++---------
2 files changed, 35 insertions(+), 9 deletions(-)
diff --git a/include/xbps.h.in b/include/xbps.h.in
index 6f707cb9..6c1a7964 100644
--- a/include/xbps.h.in
+++ b/include/xbps.h.in
@@ -1795,6 +1795,17 @@ bool xbps_mmap_file(const char *file, void **mmf, size_t *mmflen, size_t *filele
*/
char *xbps_file_hash(const char *file);
+/**
+ * Returns a raw byte buffer with the sha256 hash for the file specified
+ * by \a file.
+ *
+ * @param[in] file Path to a file.
+ * @return A pointer to a malloc(3)ed buffer, NULL otherwise and errno
+ * is set appropiately. The pointer should be free(3)d when it's no
+ * longer needed.
+ */
+unsigned char *xbps_file_hash_raw(const char *file);
+
/**
* Compares the sha256 hash of the file \a file with the sha256
* string specified by \a sha256.
diff --git a/lib/util_hash.c b/lib/util_hash.c
index 0c03c3c0..b170b432 100644
--- a/lib/util_hash.c
+++ b/lib/util_hash.c
@@ -108,24 +108,39 @@ xbps_mmap_file(const char *file, void **mmf, size_t *mmflen, size_t *filelen)
return true;
}
+unsigned char *
+xbps_file_hash_raw(const char *file)
+{
+ int fd;
+ ssize_t len;
+ unsigned char *digest, buf[65536];
+ SHA256_CTX sha256;
+
+ if ((fd = open(file, O_RDONLY)) < 0)
+ return NULL;
+ digest = malloc(SHA256_DIGEST_LENGTH);
+ assert(digest);
+ SHA256_Init(&sha256);
+ while ((len = read(fd, buf, sizeof(buf))) > 0)
+ SHA256_Update(&sha256, buf, len);
+ SHA256_Final(digest, &sha256);
+ close(fd);
+
+ return digest;
+}
+
char *
xbps_file_hash(const char *file)
{
char *res, hash[SHA256_DIGEST_LENGTH * 2 + 1];
- unsigned char digest[SHA256_DIGEST_LENGTH];
- unsigned char *mmf = NULL;
- size_t mmflen, filelen;
+ unsigned char *digest;
- if (!xbps_mmap_file(file, (void *)&mmf, &mmflen, &filelen))
+ if (!(digest = xbps_file_hash_raw(file)))
return NULL;
- if (SHA256(mmf, filelen, digest) == NULL) {
- (void)munmap(mmf, mmflen);
- return NULL;
- }
digest2string(digest, hash, SHA256_DIGEST_LENGTH);
res = strdup(hash);
- (void)munmap(mmf, mmflen);
+ free(digest);
return res;
}