sha256: Switch to GPLv2+ code

There's no need to use a GPLv3+ licensed sha256 implementation when a GPLv2+
licensed implementation exists in coreutils-6.9.

Signed-off-by: Paul Barker <paul@paulbarker.me.uk>

git-svn-id: http://opkg.googlecode.com/svn/trunk@652 e8e0d7a0-c8d9-11dd-a880-a1081c7ac358

3 files changed, 39 insertions, 50 deletions

diff --git a/configure.ac b/configure.ac
index 7b38116..fb38df7 100644
--- a/configure.ac
+++ b/configure.ac
@@ -7,7 +7,7 @@ AC_CONFIG_MACRO_DIR([m4])
 AC_CONFIG_MACRO_DIR([shave])
 
 AM_INIT_AUTOMAKE
-AC_CONFIG_HEADERS(libopkg/config.h)
+AC_CONFIG_HEADERS(config.h)
 
 AC_CANONICAL_HOST
 AC_GNU_SOURCE 
@@ -66,7 +66,7 @@ fi
 # check for sha256
 AC_ARG_ENABLE(sha256,
               AC_HELP_STRING([--enable-sha256], [Enable sha256sum check
-      (sha256.{c,h} are GPLv3 licensed) [[default=no]] ]),
+      [[default=no]] ]),
     [want_sha256="$enableval"], [want_sha256="no"])
 
 if test "x$want_sha256" = "xyes"; then
diff --git a/libopkg/sha256.c b/libopkg/sha256.c
index 0ad9444..d23c509 100644
--- a/libopkg/sha256.c
+++ b/libopkg/sha256.c
@@ -1,12 +1,12 @@
 /* sha256.c - Functions to compute SHA256 and SHA224 message digest of files or
    memory blocks according to the NIST specification FIPS-180-2.
 
-   Copyright (C) 2005, 2006, 2008 Free Software Foundation, Inc.
+   Copyright (C) 2005, 2006 Free Software Foundation, Inc.
 
-   This program is free software: you can redistribute it and/or modify
-   it under the terms of the GNU General Public License as published by
-   the Free Software Foundation, either version 3 of the License, or
-   (at your option) any later version.
+   This program is free software; you can redistribute it and/or modify it
+   under the terms of the GNU General Public License as published by the
+   Free Software Foundation; either version 2, or (at your option) any
+   later version.
 
    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ -14,7 +14,8 @@
    GNU General Public License for more details.
 
    You should have received a copy of the GNU General Public License
-   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+   along with this program; if not, write to the Free Software Foundation,
+   Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
 
 /* Written by David Madore, considerably copypasting from
    Scott G. Miller's sha1.c
@@ -85,25 +86,18 @@ sha224_init_ctx (struct sha256_ctx *ctx)
   ctx->buflen = 0;
 }
 
-/* Copy the value from v into the memory location pointed to by *cp,
-   If your architecture allows unaligned access this is equivalent to
-   * (uint32_t *) cp = v  */
-static inline void
-set_uint32 (char *cp, uint32_t v)
-{
-  memcpy (cp, &v, sizeof v);
-}
-
 /* Put result from CTX in first 32 bytes following RESBUF.  The result
-   must be in little endian byte order.  */
+   must be in little endian byte order.
+
+   IMPORTANT: On some systems it is required that RESBUF is correctly
+   aligned for a 32-bit value.  */
 void *
 sha256_read_ctx (const struct sha256_ctx *ctx, void *resbuf)
 {
   int i;
-  char *r = resbuf;
 
   for (i = 0; i < 8; i++)
-    set_uint32 (r + i * sizeof ctx->state[0], SWAP (ctx->state[i]));
+    ((uint32_t *) resbuf)[i] = SWAP (ctx->state[i]);
 
   return resbuf;
 }
@@ -112,21 +106,23 @@ void *
 sha224_read_ctx (const struct sha256_ctx *ctx, void *resbuf)
 {
   int i;
-  char *r = resbuf;
 
   for (i = 0; i < 7; i++)
-    set_uint32 (r + i * sizeof ctx->state[0], SWAP (ctx->state[i]));
+    ((uint32_t *) resbuf)[i] = SWAP (ctx->state[i]);
 
   return resbuf;
 }
 
 /* Process the remaining bytes in the internal buffer and the usual
-   prolog according to the standard and write the result to RESBUF.  */
+   prolog according to the standard and write the result to RESBUF.
+
+   IMPORTANT: On some systems it is required that RESBUF is correctly
+   aligned for a 32-bit value.  */
 static void
 sha256_conclude_ctx (struct sha256_ctx *ctx)
 {
   /* Take yet unprocessed bytes into account.  */
-  size_t bytes = ctx->buflen;
+  uint32_t bytes = ctx->buflen;
   size_t size = (bytes < 56) ? 64 / 4 : 64 * 2 / 4;
 
   /* Now count remaining bytes.  */
@@ -134,13 +130,9 @@ sha256_conclude_ctx (struct sha256_ctx *ctx)
   if (ctx->total[0] < bytes)
     ++ctx->total[1];
 
-  /* Put the 64-bit file length in *bits* at the end of the buffer.
-     Use set_uint32 rather than a simple assignment, to avoid risk of
-     unaligned access.  */
-  set_uint32 ((char *) &ctx->buffer[size - 2],
-	      SWAP ((ctx->total[1] << 3) | (ctx->total[0] >> 29)));
-  set_uint32 ((char *) &ctx->buffer[size - 1],
-	      SWAP (ctx->total[0] << 3));
+  /* Put the 64-bit file length in *bits* at the end of the buffer.  */
+  ctx->buffer[size - 2] = SWAP ((ctx->total[1] << 3) | (ctx->total[0] >> 29));
+  ctx->buffer[size - 1] = SWAP (ctx->total[0] << 3);
 
   memcpy (&((char *) ctx->buffer)[bytes], fillbuf, (size - 2) * 4 - bytes);
 
diff --git a/libopkg/sha256.h b/libopkg/sha256.h
index 6a9aed4..ccbe6cf 100644
--- a/libopkg/sha256.h
+++ b/libopkg/sha256.h
@@ -1,11 +1,11 @@
 /* Declarations of functions and data types used for SHA256 and SHA224 sum
    library functions.
-   Copyright (C) 2005, 2006, 2008, 2009 Free Software Foundation, Inc.
+   Copyright (C) 2005, 2006 Free Software Foundation, Inc.
 
-   This program is free software: you can redistribute it and/or modify
-   it under the terms of the GNU General Public License as published by
-   the Free Software Foundation, either version 3 of the License, or
-   (at your option) any later version.
+   This program is free software; you can redistribute it and/or modify it
+   under the terms of the GNU General Public License as published by the
+   Free Software Foundation; either version 2, or (at your option) any
+   later version.
 
    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ -13,7 +13,8 @@
    GNU General Public License for more details.
 
    You should have received a copy of the GNU General Public License
-   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+   along with this program; if not, write to the Free Software Foundation,
+   Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
 
 #ifndef SHA256_H
 # define SHA256_H 1
@@ -21,22 +22,16 @@
 # include <stdio.h>
 # include <stdint.h>
 
-# ifdef __cplusplus
-extern "C" {
-# endif
-
 /* Structure to save state of computation between the single steps.  */
 struct sha256_ctx
 {
   uint32_t state[8];
 
   uint32_t total[2];
-  size_t buflen;
+  uint32_t buflen;
   uint32_t buffer[32];
 };
 
-enum { SHA224_DIGEST_SIZE = 224 / 8 };
-enum { SHA256_DIGEST_SIZE = 256 / 8 };
 
 /* Initialize structure containing state of computation. */
 extern void sha256_init_ctx (struct sha256_ctx *ctx);
@@ -59,14 +54,20 @@ extern void sha256_process_bytes (const void *buffer, size_t len,
 /* Process the remaining bytes in the buffer and put result from CTX
    in first 32 (28) bytes following RESBUF.  The result is always in little
    endian byte order, so that a byte-wise output yields to the wanted
-   ASCII representation of the message digest.  */
+   ASCII representation of the message digest.
+
+   IMPORTANT: On some systems it is required that RESBUF be correctly
+   aligned for a 32 bits value.  */
 extern void *sha256_finish_ctx (struct sha256_ctx *ctx, void *resbuf);
 extern void *sha224_finish_ctx (struct sha256_ctx *ctx, void *resbuf);
 
 
 /* Put result from CTX in first 32 (28) bytes following RESBUF.  The result is
    always in little endian byte order, so that a byte-wise output yields
-   to the wanted ASCII representation of the message digest.  */
+   to the wanted ASCII representation of the message digest.
+
+   IMPORTANT: On some systems it is required that RESBUF is correctly
+   aligned for a 32 bits value.  */
 extern void *sha256_read_ctx (const struct sha256_ctx *ctx, void *resbuf);
 extern void *sha224_read_ctx (const struct sha256_ctx *ctx, void *resbuf);
 
@@ -84,8 +85,4 @@ extern int sha224_stream (FILE *stream, void *resblock);
 extern void *sha256_buffer (const char *buffer, size_t len, void *resblock);
 extern void *sha224_buffer (const char *buffer, size_t len, void *resblock);
 
-# ifdef __cplusplus
-}
-# endif
-
 #endif