Date: Fri, 16 Mar 2001 21:43:10 +0200 From: Peter Pentchev <roam@orbitel.bg> To: Poul-Henning Kamp <phk@critter.freebsd.dk> Cc: arch@FreeBSD.ORG Subject: Re: add MD5Chunk(filename, .., offset, length) to libmd Message-ID: <20010316214310.A8968@ringworld.oblivion.bg> In-Reply-To: <14989.984770783@critter>; from phk@critter.freebsd.dk on Fri, Mar 16, 2001 at 08:26:23PM %2B0100 References: <20010316210833.C8245@ringworld.oblivion.bg> <14989.984770783@critter>
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On Fri, Mar 16, 2001 at 08:26:23PM +0100, Poul-Henning Kamp wrote:
> In message <20010316210833.C8245@ringworld.oblivion.bg>, Peter Pentchev writes:
> >Hi,
> >
> >(I wonder if I'm starting another bikeshed, but oh well ;)
> >
> >As phk pointed out in the SITE MD5 thread, it is sometimes useful
> >to compute the MD5 hash over a range of a file. I agree this is trivial
> >to implement, but why not have it in our standard toolbox?
>
> If you include manpage patches I'll commit it.
Thanks! :)
OK, here's the libmd part. How about /sbin/md5? ALT_RFLAG or not?
Or not at all? :)
G'luck,
Peter
--
.siht ekil ti gnidaer eb d'uoy ,werbeH ni erew ecnetnes siht fI
Index: src/sys/sys/md5.h
===================================================================
RCS file: /home/ncvs/src/sys/sys/md5.h,v
retrieving revision 1.13
diff -u -r1.13 md5.h
--- src/sys/sys/md5.h 1999/12/29 04:24:44 1.13
+++ src/sys/sys/md5.h 2001/03/16 19:38:33
@@ -34,6 +34,7 @@
} MD5_CTX;
#include <sys/cdefs.h>
+#include <sys/types.h>
__BEGIN_DECLS
void MD5Init (MD5_CTX *);
@@ -42,6 +43,7 @@
void MD5Final (unsigned char [16], MD5_CTX *);
char * MD5End(MD5_CTX *, char *);
char * MD5File(const char *, char *);
+char * MD5Chunk(const char *, char *, off_t, off_t);
char * MD5Data(const unsigned char *, unsigned int, char *);
#ifdef _KERNEL
void MD5Transform __P((u_int32_t [4], const unsigned char [64]));
Index: src/lib/libmd/md2.h
===================================================================
RCS file: /home/ncvs/src/lib/libmd/md2.h,v
retrieving revision 1.8
diff -u -r1.8 md2.h
--- src/lib/libmd/md2.h 1999/08/28 00:05:04 1.8
+++ src/lib/libmd/md2.h 2001/03/16 19:38:33
@@ -31,6 +31,7 @@
} MD2_CTX;
#include <sys/cdefs.h>
+#include <sys/types.h>
__BEGIN_DECLS
void MD2Init(MD2_CTX *);
@@ -39,6 +40,7 @@
void MD2Final(unsigned char [16], MD2_CTX *);
char * MD2End(MD2_CTX *, char *);
char * MD2File(const char *, char *);
+char * MD2Chunk(const char *, char *, off_t, off_t);
char * MD2Data(const unsigned char *, unsigned int, char *);
__END_DECLS
Index: src/lib/libmd/md4.h
===================================================================
RCS file: /home/ncvs/src/lib/libmd/md4.h,v
retrieving revision 1.9
diff -u -r1.9 md4.h
--- src/lib/libmd/md4.h 1999/08/28 00:05:05 1.9
+++ src/lib/libmd/md4.h 2001/03/16 19:38:33
@@ -33,6 +33,7 @@
} MD4_CTX;
#include <sys/cdefs.h>
+#include <sys/types.h>
__BEGIN_DECLS
void MD4Init(MD4_CTX *);
@@ -41,6 +42,7 @@
void MD4Final(unsigned char [16], MD4_CTX *);
char * MD4End(MD4_CTX *, char *);
char * MD4File(const char *, char *);
+char * MD4Chunk(const char *, char *, off_t, off_t);
char * MD4Data(const unsigned char *, unsigned int, char *);
__END_DECLS
Index: src/lib/libmd/mdX.3
===================================================================
RCS file: /home/ncvs/src/lib/libmd/mdX.3,v
retrieving revision 1.18
diff -u -r1.18 mdX.3
--- src/lib/libmd/mdX.3 2000/12/14 11:45:18 1.18
+++ src/lib/libmd/mdX.3 2001/03/16 19:38:33
@@ -18,6 +18,7 @@
.Nm MDXFinal ,
.Nm MDXEnd ,
.Nm MDXFile ,
+.Nm MDXChunk ,
.Nm MDXData
.Nd calculate the RSA Data Security, Inc., ``MDX'' message digest
.Sh LIBRARY
@@ -38,6 +39,8 @@
.Ft "char *"
.Fn MDXFile "const char *filename" "char *buf"
.Ft "char *"
+.Fn MDXChunk "const char *filename" "char *buf" "off_t offset" "off_t length"
+.Ft "char *"
.Fn MDXData "const unsigned char *data" "unsigned int len" "char *buf"
.Sh DESCRIPTION
The MDX functions calculate a 128-bit cryptographic checksum (digest)
@@ -88,6 +91,23 @@
.Fn MDXEnd
to return the result.
If the file cannot be opened, a null pointer is returned.
+.Fn MDXChunk
+is similar to
+.Fn MDXFile ,
+but it only calculates the digest over a byte-range of the file specified,
+starting at
+.Ar offset
+and spanning
+.Ar length
+bytes.
+If the
+.Ar length
+parameter is specified as 0, or more than the length of the remaining part
+of the file,
+.Fn MDXChunk
+calculates the digest from
+.Ar offset
+to the end of file.
.Fn MDXData
calculates the digest of a chunk of data in memory, and uses
.Fn MDXEnd
Index: src/lib/libmd/mdXhl.c
===================================================================
RCS file: /home/ncvs/src/lib/libmd/mdXhl.c,v
retrieving revision 1.13
diff -u -r1.13 mdXhl.c
--- src/lib/libmd/mdXhl.c 1999/08/28 00:05:07 1.13
+++ src/lib/libmd/mdXhl.c 2001/03/16 19:38:33
@@ -11,6 +11,7 @@
*/
#include <sys/types.h>
+#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
@@ -53,6 +54,41 @@
while ((i = read(f,buffer,sizeof buffer)) > 0) {
MDXUpdate(&ctx,buffer,i);
}
+ j = errno;
+ close(f);
+ errno = j;
+ if (i < 0) return 0;
+ return MDXEnd(&ctx, buf);
+}
+
+char *
+MDXChunk(const char *filename, char *buf, off_t ofs, off_t len)
+{
+ unsigned char buffer[BUFSIZ];
+ MDX_CTX ctx;
+ struct stat stbuf;
+ int f, i, j;
+ off_t n;
+
+ MDXInit(&ctx);
+ f = open(filename, O_RDONLY);
+ if (f < 0) return 0;
+ if (fstat(f, &stbuf) < 0) return 0;
+ if (ofs > stbuf.st_size)
+ ofs = stbuf.st_size;
+ if ((len == 0) || (len > stbuf.st_size - ofs))
+ len = stbuf.st_size - ofs;
+ if (lseek(f, ofs, SEEK_SET) < 0) return 0;
+ n = len;
+ while (n > 0) {
+ if (n > sizeof(buffer))
+ i = read(f, buffer, sizeof(buffer));
+ else
+ i = read(f, buffer, n);
+ if (i < 0) break;
+ MDXUpdate(&ctx, buffer, i);
+ n -= i;
+ }
j = errno;
close(f);
errno = j;
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