sha1: allow limiting the size of the data passed to SHA1_Update()

Using the previous commit's inredirection mechanism for SHA1,
support a chunked implementation of SHA1_Update() that limits the
amount of data in the chunk passed to SHA1_Update().

This is enabled by using the Makefile variable SHA1_MAX_BLOCK_SIZE
to specify chunk size.  When using Apple's CommonCrypto library this
is set to 1GiB (the implementation cannot handle more 4GiB).

Signed-off-by: Atousa Pahlevan Duprat <apahlevan@ieee.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/Makefile b/Makefile
index 7482a4dbab458b1b82a7cb683ce7dc6f41fd4145..8ffcf37d5f2e765f8f6460eb3c67ff11d7bad7d1 100644 (file)
--- a/Makefile
+++ b/Makefile
@@ -141,6 +141,10 @@ all::
 # Define PPC_SHA1 environment variable when running make to make use of
 # a bundled SHA1 routine optimized for PowerPC.
 #
+# Define SHA1_MAX_BLOCK_SIZE to limit the amount of data that will be hashed
+# in one call to the platform's SHA1_Update(). e.g. APPLE_COMMON_CRYPTO
+# wants 'SHA1_MAX_BLOCK_SIZE=1024L*1024L*1024L' defined.
+#
 # Define NEEDS_CRYPTO_WITH_SSL if you need -lcrypto when using -lssl (Darwin).
 #
 # Define NEEDS_SSL_WITH_CRYPTO if you need -lssl when using -lcrypto (Darwin).
@@ -1276,6 +1280,11 @@ ifdef NO_POSIX_GOODIES
        BASIC_CFLAGS += -DNO_POSIX_GOODIES
 endif
 
+ifdef APPLE_COMMON_CRYPTO
+       # Apple CommonCrypto requires chunking
+       SHA1_MAX_BLOCK_SIZE = 1024L*1024L*1024L
+endif
+
 ifdef BLK_SHA1
        SHA1_HEADER = "block-sha1/sha1.h"
        LIB_OBJS += block-sha1/sha1.o
@@ -1294,6 +1303,10 @@ endif
 endif
 endif
 
+ifdef SHA1_MAX_BLOCK_SIZE
+       LIB_OBJS += compat/sha1-chunked.o
+       BASIC_CFLAGS += -DSHA1_MAX_BLOCK_SIZE="$(SHA1_MAX_BLOCK_SIZE)"
+endif
 ifdef NO_PERL_MAKEMAKER
        export NO_PERL_MAKEMAKER
 endif

diff --git a/cache.h b/cache.h
index 0d89ad8a3a9eedb0b3af5ffdb6d74c08fa714c38..0adc7ef7f7c628db3e7b36da30f3f555f7d12ded 100644 (file)
--- a/cache.h
+++ b/cache.h
@@ -30,6 +30,12 @@
 #define git_SHA1_Update                platform_SHA1_Update
 #define git_SHA1_Final         platform_SHA1_Final
 
+#ifdef SHA1_MAX_BLOCK_SIZE
+#include "compat/sha1-chunked.h"
+#undef git_SHA1_Update
+#define git_SHA1_Update                git_SHA1_Update_Chunked
+#endif
+
 #include <zlib.h>
 typedef struct git_zstream {
        z_stream z;

diff --git a/compat/apple-common-crypto.h b/compat/apple-common-crypto.h
index c8b9b0e1a6ce63d16aec142611d03fbe24784b43..d3fb2641813404a95709d2b219b9ab1fa1434296 100644 (file)
--- a/compat/apple-common-crypto.h
+++ b/compat/apple-common-crypto.h
@@ -16,6 +16,10 @@
 #undef TYPE_BOOL
 #endif
 
+#ifndef SHA1_MAX_BLOCK_SIZE
+#error Using Apple Common Crypto library requires setting SHA1_MAX_BLOCK_SIZE
+#endif
+
 #ifdef APPLE_LION_OR_NEWER
 #define git_CC_error_check(pattern, err) \
        do { \

diff --git a/compat/sha1-chunked.c b/compat/sha1-chunked.c
new file mode 100644 (file)
index 0000000..6adfcfd
--- /dev/null
+++ b/compat/sha1-chunked.c
@@ -0,0 +1,19 @@
+#include "cache.h"
+
+int git_SHA1_Update_Chunked(platform_SHA_CTX *c, const void *data, size_t len)
+{
+       size_t nr;
+       size_t total = 0;
+       const char *cdata = (const char*)data;
+
+       while (len) {
+               nr = len;
+               if (nr > SHA1_MAX_BLOCK_SIZE)
+                       nr = SHA1_MAX_BLOCK_SIZE;
+               platform_SHA1_Update(c, cdata, nr);
+               total += nr;
+               cdata += nr;
+               len -= nr;
+       }
+       return total;
+}

diff --git a/compat/sha1-chunked.h b/compat/sha1-chunked.h
new file mode 100644 (file)
index 0000000..7b2df28
--- /dev/null
+++ b/compat/sha1-chunked.h
@@ -0,0 +1,2 @@
+
+int git_SHA1_Update_Chunked(platform_SHA_CTX *c, const void *data, size_t len);