dev-util/bsdiff/files/4.3_bspatch-support-input-output-positioning.patch

--- bsdiff-4.3/bspatch.c	2005-08-16 15:14:00.000000000 -0700
+++ bsdiff-4.3-new/bspatch.c	2010-10-12 13:57:08.000000000 -0700
@@ -3,7 +3,7 @@
  * All rights reserved
  *
  * Redistribution and use in source and binary forms, with or without
- * modification, are permitted providing that the following conditions 
+ * modification, are permitted providing that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
@@ -29,6 +29,9 @@
 #endif
 
 #include <bzlib.h>
+#include <errno.h>
+#include <inttypes.h>
+#include <stdint.h>
 #include <stdlib.h>
 #include <stdio.h>
 #include <string.h>
@@ -36,6 +39,264 @@
 #include <unistd.h>
 #include <fcntl.h>
 
+#define JOIN(a, b) __JOIN(a, b)
+#define __JOIN(a, b) a ## b
+#define COMPILE_ASSERT(expr, message) \
+	typedef char JOIN(message, JOIN(_, __LINE__)) [(expr) ? 1 : -1]
+
+COMPILE_ASSERT(sizeof(int64_t) == 8, int64_t_64_bit);
+COMPILE_ASSERT(sizeof(off_t) == 8, off_t_64_bit);
+
+#define MIN(a, b) \
+	((a) < (b) ? (a) : (b))
+
+static const char kFdFilePrefix[] = "/dev/fd/";
+
+// Reads next int from *ints. The int should be terminated with a comma
+// or NULL char. *ints will be updated to the space right after the comma
+// or set to NULL if this was the last number. This assumes the input is
+// a valid string, as validated with PositionsStringIsValid().
+// Returns 1 on success.
+int NextInt64(const char** ints, int64_t *out) {
+	if (!ints[0])
+		return 0;
+	int r = sscanf(*ints, "%" PRIi64, out);
+	if (r == 1) {
+		const char* next_comma = strchr(*ints, ',');
+		const char* next_colon = strchr(*ints, ':');
+		if (!next_comma && !next_colon)
+			*ints = NULL;
+		else if (!next_comma)
+			*ints = next_colon + 1;
+		else if (!next_colon)
+			*ints = next_comma + 1;
+		else
+			*ints = MIN(next_comma, next_colon) + 1;
+		return 1;
+	}
+	return 0;
+}
+
+COMPILE_ASSERT(sizeof(intmax_t) == 8, intmax_t_not_64_bit);
+
+// Returns 1 if str can be converted to int64_t without over/underflowing.
+// str is assumed to point to an optional negative sign followed by numbers,
+// optionally followed by non-numeric characters, followed by '\0'.
+int IsValidInt64(const char* str) {
+	char* end_ptr = 0;
+	errno = 0;
+	intmax_t result = strtoimax(str, &end_ptr, /* base: */ 10);
+	return errno == 0;
+}
+
+// Input validator. Make sure the positions string is well formatted.
+// All numerical values are checked to make sure they don't over/underflow
+// int64_t. Returns 1 if valid.
+int PositionsStringIsValid(const char* positions) {
+	if (positions == NULL)
+		errx(1, "bad string");
+
+	// Special case: empty string is valid
+	if (!positions[0])
+		return 1;
+
+	// Use a state machine to determine if the string is valid.
+	// Key: (s): state, ((s)) valid end state.
+	// n (negative_valid) is a boolean that starts out as true.
+	// If n is true, ':' is the delimiter, otherwise ','.
+	//
+	//         .--------------------------.
+	//         |                          | n ? ':' : ',' ; n = !n
+	//         V  '-'&&n           0-9    |
+	// start->(0)------------->(1)----->((2))---.
+	//           `--------------------->     <--' 0-9
+	//              0-9
+	int state = 0;
+	int negative_valid = 1;
+	const char* number_start = positions;
+	for (;; positions++) {
+		char c = *positions;
+		switch (state) {
+			case 0:
+				if (c == '-' && negative_valid) {
+					state = 1;
+					continue;
+				}
+				if (isdigit(c)) {
+					state = 2;
+					continue;
+				}
+				return 0;
+			case 1:
+				if (isdigit(c)) {
+					state = 2;
+					continue;
+				}
+				return 0;
+			case 2:
+				if (isdigit(c))
+					continue;
+				// number_start must point to a valid number
+				if (!IsValidInt64(number_start)) {
+					return 0;
+				}
+				if ((negative_valid && c == ':') ||
+				    (!negative_valid && c == ',')) {
+					state = 0;
+					number_start = positions + 1;
+					negative_valid = !negative_valid;
+					continue;
+				}
+				return (c == '\0');
+		}
+	}
+}
+
+static const int64_t kMaxLength = sizeof(size_t) > 4 ? INT64_MAX : SIZE_MAX;
+
+// Reads into a buffer a series of byte ranges from filename.
+// Each range is a pair of comma-separated ints from positions.
+// -1 as an offset means a sparse-hole.
+// E.g. If positions were "1,5:23,4:-1,8:3,7", then we would return a buffer
+// consisting of 5 bytes from offset 1 of the file, followed by
+// 4 bytes from offset 23, then 8 bytes of all zeros, then 7 bytes from
+// offset 3 in the file.
+// Returns NULL on error.
+static char* PositionedRead(const char* filename,
+                            const char* positions,
+                            ssize_t* old_size) {
+	if (!PositionsStringIsValid(positions)) {
+		errx(1, "invalid positions string for read\n");
+	}
+
+	// Get length
+	const char* p = positions;
+	int64_t length = 0;
+	for (;;) {
+		int64_t value;
+		if (0 == NextInt64(&p, &value)) {
+			break;
+		}
+		int r = NextInt64(&p, &value);
+		if (r == 0) {
+			errx(1, "bad length parse\n");
+		}
+		if (value < 0) {
+			errx(1, "length can't be negative\n");
+		}
+		length += value;
+	}
+
+	// Malloc
+	if (length > 0x40000000) {  // 1 GiB; sanity check
+		errx(1, "Read length too long (exceeds 1 GiB)");
+	}
+	// Following bsdiff convention, allocate length + 1 to avoid malloc(0)
+	char* buf = malloc(length + 1);
+	if (buf == NULL) {
+		errx(1, "malloc failed\n");
+	}
+	char* buf_tail = buf;
+
+	int fd = -1;
+	int should_close = 1;
+	if (strlen(filename) > strlen(kFdFilePrefix) &&
+		!strncmp(filename, kFdFilePrefix, strlen(kFdFilePrefix))) {
+		sscanf(filename + strlen(kFdFilePrefix), "%d", &fd);
+		should_close = 0;
+	} else {
+		fd = open(filename, O_RDONLY);
+	}
+	if (fd < 0) {
+		errx(1, "open failed for read\n");
+	}
+
+	// Read bytes
+	p = positions;
+	for (;;) {
+		int64_t offset, read_length;
+		if (NextInt64(&p, &offset) == 0) {
+			break;
+		}
+		if (offset < 0) {
+			errx(1, "no support for sparse positions "
+			     "yet during read\n");
+		}
+		if (NextInt64(&p, &read_length) == 0) {
+			errx(1, "bad length parse (should never happen)\n");
+		}
+		if (read_length < 0) {
+			errx(1, "length can't be negative "
+			     "(should never happen)\n");
+		}
+		if (read_length > kMaxLength) {
+			errx(1, "read length too large\n");
+		}
+		ssize_t rc = pread(fd, buf_tail, (size_t)read_length, (off_t)offset);
+		if (rc != read_length) {
+			errx(1, "read failed\n");
+		}
+		buf_tail += rc;
+	}
+	if (should_close)
+		close(fd);
+	*old_size = length;
+	return buf;
+}
+
+static void PositionedWrite(const char* filename,
+                            const char* positions,
+                            const char* buf,
+                            ssize_t new_size) {
+	if (!PositionsStringIsValid(positions)) {
+		errx(1, "invalid positions string for write\n");
+	}
+	int fd = -1;
+	int should_close = 1;
+	if (strlen(filename) > strlen(kFdFilePrefix) &&
+		!strncmp(filename, kFdFilePrefix, strlen(kFdFilePrefix))) {
+		sscanf(filename + strlen(kFdFilePrefix), "%d", &fd);
+		should_close = 0;
+	} else {
+		fd = open(filename, O_WRONLY | O_CREAT, 0666);
+	}
+	if (fd < 0) {
+		errx(1, "open failed for write\n");
+	}
+
+	for (;;) {
+		int64_t offset, length;
+		if (NextInt64(&positions, &offset) == 0) {
+			break;
+		}
+		if (NextInt64(&positions, &length) == 0) {
+			errx(1, "bad length parse for write\n");
+		}
+		if (length < 0) {
+			errx(1, "length can't be negative for write\n");
+		}
+		if (length > kMaxLength) {
+			errx(1, "write length too large\n");
+		}
+
+		if (offset < 0) {
+			// Sparse hole. Skip.
+		} else {
+			ssize_t rc = pwrite(fd, buf, (size_t)length, (off_t)offset);
+			if (rc != length) {
+				errx(1, "write failed\n");
+			}
+		}
+		buf += length;
+		new_size -= length;
+	}
+	if (new_size != 0) {
+		errx(1, "output position length doesn't match new size\n");
+	}
+	if (should_close)
+		close(fd);
+}
+
 static off_t offtin(u_char *buf)
 {
 	off_t y;
@@ -69,7 +330,13 @@
 	off_t lenread;
 	off_t i;
 
-	if(argc!=4) errx(1,"usage: %s oldfile newfile patchfile\n",argv[0]);
+	if ((argc != 6) && (argc != 4)) {
+		errx(1,"usage: %s oldfile newfile patchfile \\\n"
+			"  [in_offset,in_length,in_offset,in_length,... \\\n"
+			"  out_offset,out_length,"
+			"out_offset,out_length,...]\n",argv[0]);
+	}
+	int using_positioning = (argc == 6);
 
 	/* Open patch file */
 	if ((f = fopen(argv[3], "r")) == NULL)
@@ -132,12 +399,18 @@
 	if ((epfbz2 = BZ2_bzReadOpen(&ebz2err, epf, 0, 0, NULL, 0)) == NULL)
 		errx(1, "BZ2_bzReadOpen, bz2err = %d", ebz2err);
 
-	if(((fd=open(argv[1],O_RDONLY,0))<0) ||
-		((oldsize=lseek(fd,0,SEEK_END))==-1) ||
-		((old=malloc(oldsize+1))==NULL) ||
-		(lseek(fd,0,SEEK_SET)!=0) ||
-		(read(fd,old,oldsize)!=oldsize) ||
-		(close(fd)==-1)) err(1,"%s",argv[1]);
+	// Read
+
+	if (!using_positioning) {
+		if(((fd=open(argv[1],O_RDONLY,0))<0) ||
+			((oldsize=lseek(fd,0,SEEK_END))==-1) ||
+			((old=malloc(oldsize+1))==NULL) ||
+			(lseek(fd,0,SEEK_SET)!=0) ||
+			(read(fd,old,oldsize)!=oldsize) ||
+			(close(fd)==-1)) err(1,"%s",argv[1]);
+	} else {
+		old = PositionedRead(argv[1], argv[4], &oldsize);
+	}
 	if((new=malloc(newsize+1))==NULL) err(1,NULL);
 
 	oldpos=0;newpos=0;
@@ -193,9 +466,13 @@
 		err(1, "fclose(%s)", argv[3]);
 
 	/* Write the new file */
-	if(((fd=open(argv[2],O_CREAT|O_TRUNC|O_WRONLY,0666))<0) ||
-		(write(fd,new,newsize)!=newsize) || (close(fd)==-1))
-		err(1,"%s",argv[2]);
+	if (!using_positioning) {
+		if(((fd=open(argv[2],O_CREAT|O_TRUNC|O_WRONLY,0666))<0) ||
+			(write(fd,new,newsize)!=newsize) || (close(fd)==-1))
+			err(1,"%s",argv[2]);
+	} else {
+		PositionedWrite(argv[2], argv[5], new, newsize);
+	}
 
 	free(new);
 	free(old);