cramfs.patch

sm86xx rootfs来源包括补丁（ GPL ）的

+extern char *xreadlink(const char *path)
+{                       
+	static const int GROWBY = 80; /* how large we will grow strings by */
+
+	char *buf = NULL;   
+	int bufsize = 0, readsize = 0;
+
+	do {
+		buf = xrealloc(buf, bufsize += GROWBY);
+		readsize = readlink(path, buf, bufsize); /* 1st try */
+		if (readsize == -1) {
+		    perror_msg("%s:%s", progname, path);
+		    return NULL;
+		}
+	}           
+	while (bufsize < readsize + 1);
+
+	buf[readsize] = '\0';
+
+	return buf;
+}       
+
 static void map_entry(struct entry *entry)
 {
 	if (entry->path) {
 		entry->fd = open(entry->path, O_RDONLY);
 		if (entry->fd < 0) {
-			die(MKFS_ERROR, 1, "open failed: %s", entry->path);
+			error_msg_and_die("open failed: %s", entry->path);
 		}
 		entry->uncompressed = mmap(NULL, entry->size, PROT_READ, MAP_PRIVATE, entry->fd, 0);
 		if (entry->uncompressed == MAP_FAILED) {
-			die(MKFS_ERROR, 1, "mmap failed: %s", entry->path);
+			error_msg_and_die("mmap failed: %s", entry->path);
 		}
 	}
 }
@@ -174,8 +317,9 @@
 {
 	if (entry->path) {
 		if (munmap(entry->uncompressed, entry->size) < 0) {
-			die(MKFS_ERROR, 1, "munmap failed: %s", entry->path);
+			error_msg_and_die("munmap failed: %s", entry->path);
 		}
+		entry->uncompressed=NULL;
 		close(entry->fd);
 	}
 }
@@ -204,7 +348,8 @@
 		find_identical_file(orig->next, newfile));
 }
 
-static void eliminate_doubles(struct entry *root, struct entry *orig) {
+static void eliminate_doubles(struct entry *root, struct entry *orig) 
+{
 	if (orig) {
 		if (orig->size && (orig->path || orig->uncompressed))
 			find_identical_file(root, orig);
@@ -232,10 +377,7 @@
 
 	/* Set up the path. */
 	/* TODO: Reuse the parent's buffer to save memcpy'ing and duplication. */
-	path = malloc(len + 1 + MAX_INPUT_NAMELEN + 1);
-	if (!path) {
-		die(MKFS_ERROR, 1, "malloc failed");
-	}
+	path = xmalloc(len + 1 + MAX_INPUT_NAMELEN + 1);
 	memcpy(path, name, len);
 	endpath = path + len;
 	*endpath = '/';
@@ -245,7 +387,7 @@
 	dircount = scandir(name, &dirlist, 0, cramsort);
 
 	if (dircount < 0) {
-		die(MKFS_ERROR, 1, "scandir failed: %s", name);
+		error_msg_and_die("scandir failed: %s", name);
 	}
 
 	/* process directory */
@@ -269,25 +411,20 @@
 		}
 		namelen = strlen(dirent->d_name);
 		if (namelen > MAX_INPUT_NAMELEN) {
-			die(MKFS_ERROR, 0,
-				"very long (%u bytes) filename found: %s\n"
-				"please increase MAX_INPUT_NAMELEN in mkcramfs.c and recompile",
+			error_msg_and_die(
+				"Very long (%u bytes) filename `%s' found.\n"
+				" Please increase MAX_INPUT_NAMELEN in mkcramfs.c and recompile.  Exiting.\n",
 				namelen, dirent->d_name);
 		}
 		memcpy(endpath, dirent->d_name, namelen + 1);
 
 		if (lstat(path, &st) < 0) {
+			perror(endpath);
 			warn_skip = 1;
 			continue;
 		}
-		entry = calloc(1, sizeof(struct entry));
-		if (!entry) {
-			die(MKFS_ERROR, 1, "calloc failed");
-		}
-		entry->name = strdup(dirent->d_name);
-		if (!entry->name) {
-			die(MKFS_ERROR, 1, "strdup failed");
-		}
+		entry = xcalloc(1, sizeof(struct entry));
+		entry->name = xstrdup(dirent->d_name);
 		/* truncate multi-byte UTF-8 filenames on character boundary */
 		if (namelen > CRAMFS_MAXPATHLEN) {
 			namelen = CRAMFS_MAXPATHLEN;
@@ -297,24 +434,25 @@
 				namelen--;
 				/* are we reasonably certain it was UTF-8 ? */
 				if (entry->name[namelen] < 0x80 || !namelen) {
-					die(MKFS_ERROR, 0, "cannot truncate filenames not encoded in UTF-8");
+					error_msg_and_die("cannot truncate filenames not encoded in UTF-8");
 				}
 			}
 			entry->name[namelen] = '\0';
 		}
 		entry->mode = st.st_mode;
 		entry->size = st.st_size;
-		entry->uid = st.st_uid;
+		entry->uid = opt_squash ? 0 : st.st_uid;
 		if (entry->uid >= 1 << CRAMFS_UID_WIDTH)
 			warn_uid = 1;
-		entry->gid = st.st_gid;
-		if (entry->gid >= 1 << CRAMFS_GID_WIDTH)
+		entry->gid = opt_squash ? 0 : st.st_gid;
+		if (entry->gid >= 1 << CRAMFS_GID_WIDTH) {
 			/* TODO: We ought to replace with a default
 			   gid instead of truncating; otherwise there
 			   are security problems.  Maybe mode should
 			   be &= ~070.  Same goes for uid once Linux
 			   supports >16-bit uids. */
 			warn_gid = 1;
+		}
 		size = sizeof(struct cramfs_inode) + ((namelen + 3) & ~3);
 		*fslen_ub += size;
 		if (S_ISDIR(st.st_mode)) {
@@ -325,21 +463,15 @@
 					warn_skip = 1;
 					continue;
 				}
-				entry->path = strdup(path);
-				if (!entry->path) {
-					die(MKFS_ERROR, 1, "strdup failed");
-				}
+				entry->path = xstrdup(path);
 				if ((entry->size >= 1 << CRAMFS_SIZE_WIDTH)) {
 					warn_size = 1;
 					entry->size = (1 << CRAMFS_SIZE_WIDTH) - 1;
 				}
 			}
 		} else if (S_ISLNK(st.st_mode)) {
-			entry->uncompressed = malloc(entry->size);
+			entry->uncompressed = xreadlink(path);
 			if (!entry->uncompressed) {
-				die(MKFS_ERROR, 1, "malloc failed");
-			}
-			if (readlink(path, entry->uncompressed, entry->size) < 0) {
 				warn_skip = 1;
 				continue;
 			}
@@ -351,7 +483,7 @@
 			if (entry->size & -(1<<CRAMFS_SIZE_WIDTH))
 				warn_dev = 1;
 		} else {
-			die(MKFS_ERROR, 0, "bogus file type: %s", entry->name);
+			error_msg_and_die("bogus file type: %s", entry->name);
 		}
 
 		if (S_ISREG(st.st_mode) || S_ISLNK(st.st_mode)) {
@@ -378,7 +510,9 @@
 	struct cramfs_super *super = (struct cramfs_super *) base;
 	unsigned int offset = sizeof(struct cramfs_super) + image_length;
 
-	offset += opt_pad;	/* 0 if no padding */
+	if (opt_pad) {
+		offset += opt_pad;	/* 0 if no padding */
+	}
 
 	super->magic = CRAMFS_MAGIC;
 	super->flags = CRAMFS_FLAG_FSID_VERSION_2 | CRAMFS_FLAG_SORTED_DIRS;
@@ -414,10 +548,10 @@
 	struct cramfs_inode *inode = (struct cramfs_inode *) (base + entry->dir_offset);
 
 	if ((offset & 3) != 0) {
-		die(MKFS_ERROR, 0, "illegal offset of %lu bytes", offset);
+		error_msg_and_die("illegal offset of %lu bytes", offset);
 	}
 	if (offset >= (1 << (2 + CRAMFS_OFFSET_WIDTH))) {
-		die(MKFS_ERROR, 0, "filesystem too big");
+		error_msg_and_die("filesystem too big");
 	}
 	inode->offset = (offset >> 2);
 }
@@ -429,7 +563,7 @@
  */
 static void print_node(struct entry *e)
 {
-	char info[10];
+	char info[12];
 	char type = '?';
 
 	if (S_ISREG(e->mode)) type = 'f';
@@ -442,11 +576,11 @@
 
 	if (S_ISCHR(e->mode) || (S_ISBLK(e->mode))) {
 		/* major/minor numbers can be as high as 2^12 or 4096 */
-		snprintf(info, 10, "%4d,%4d", major(e->size), minor(e->size));
+		snprintf(info, 11, "%4d,%4d", major(e->size), minor(e->size));
 	}
 	else {
 		/* size be as high as 2^24 or 16777216 */
-		snprintf(info, 10, "%9d", e->size);
+		snprintf(info, 11, "%9d", e->size);
 	}
 
 	printf("%c %04o %s %5d:%-3d %s\n",
@@ -462,17 +596,9 @@
 {
 	int stack_entries = 0;
 	int stack_size = 64;
-	struct entry **entry_stack;
-
-	entry_stack = malloc(stack_size * sizeof(struct entry *));
-	if (!entry_stack) {
-		die(MKFS_ERROR, 1, "malloc failed");
-	}
-
-	if (opt_verbose) {
-		printf("root:\n");
-	}
+	struct entry **entry_stack = NULL;
 
+	entry_stack = xmalloc(stack_size * sizeof(struct entry *));
 	for (;;) {
 		int dir_start = stack_entries;
 		while (entry) {
@@ -506,10 +632,7 @@
 			if (entry->child) {
 				if (stack_entries >= stack_size) {
 					stack_size *= 2;
-					entry_stack = realloc(entry_stack, stack_size * sizeof(struct entry *));
-					if (!entry_stack) {
-						die(MKFS_ERROR, 1, "realloc failed");
-					}
+					entry_stack = xrealloc(entry_stack, stack_size * sizeof(struct entry *));
 				}
 				entry_stack[stack_entries] = entry;
 				stack_entries++;
@@ -543,7 +666,7 @@
 
 		set_data_offset(entry, base, offset);
 		if (opt_verbose) {
-			printf("%s:\n", entry->name);
+		    printf("'%s':\n", entry->name);
 		}
 		entry = entry->child;
 	}
@@ -553,16 +676,21 @@
 
 static int is_zero(char const *begin, unsigned len)
 {
-	/* Returns non-zero iff the first LEN bytes from BEGIN are all NULs. */
-	return (len-- == 0 ||
-		(begin[0] == '\0' &&
-		 (len-- == 0 ||
-		  (begin[1] == '\0' &&
-		   (len-- == 0 ||
-		    (begin[2] == '\0' &&
-		     (len-- == 0 ||
-		      (begin[3] == '\0' &&
-		       memcmp(begin, begin + 4, len) == 0))))))));
+	if (opt_holes)
+		/* Returns non-zero iff the first LEN bytes from BEGIN are
+		   all NULs. */
+		return (len-- == 0 ||
+			(begin[0] == '\0' &&
+			 (len-- == 0 ||
+			  (begin[1] == '\0' &&
+			   (len-- == 0 ||
+			    (begin[2] == '\0' &&
+			     (len-- == 0 ||
+			      (begin[3] == '\0' &&
+			       memcmp(begin, begin + 4, len) == 0))))))));
+	else
+		/* Never create holes. */
+		return 0;
 }
 
 /*
@@ -575,37 +703,34 @@
  * Note that size > 0, as a zero-sized file wouldn't ever
  * have gotten here in the first place.
  */
-static unsigned int do_compress(char *base, unsigned int offset, char const *name, char *uncompressed, unsigned int size)
+static unsigned int do_compress(char *base, unsigned int offset, struct entry *entry)
 {
+	unsigned int size = entry->size;
 	unsigned long original_size = size;
 	unsigned long original_offset = offset;
 	unsigned long new_size;
 	unsigned long blocks = (size - 1) / blksize + 1;
 	unsigned long curr = offset + 4 * blocks;
 	int change;
+	char *uncompressed = entry->uncompressed;
 
-	total_blocks += blocks;
+	total_blocks += blocks; 
 
 	do {
 		unsigned long len = 2 * blksize;
 		unsigned int input = size;
-		int err;
-
 		if (input > blksize)
 			input = blksize;
 		size -= input;
-		if (!(opt_holes && is_zero (uncompressed, input))) {
-			err = compress2(base + curr, &len, uncompressed, input, Z_BEST_COMPRESSION);
-			if (err != Z_OK) {
-				die(MKFS_ERROR, 0, "compression error: %s", zError(err));
-			}
+		if (!is_zero (uncompressed, input)) {
+			compress(base + curr, &len, uncompressed, input);
 			curr += len;
 		}
 		uncompressed += input;
 
 		if (len > blksize*2) {
 			/* (I don't think this can happen with zlib.) */
-			die(MKFS_ERROR, 0, "AIEEE: block \"compressed\" to > 2*blocklength (%ld)", len);
+			error_msg_and_die("AIEEE: block \"compressed\" to > 2*blocklength (%ld)\n", len);
 		}
 
 		*(u32 *) (base + offset) = curr;
@@ -618,10 +743,12 @@
 	   st_blocks * 512.  But if you say that then perhaps
 	   administrative data should also be included in both. */
 	change = new_size - original_size;
-	if (opt_verbose > 1) {
-		printf("%6.2f%% (%+d bytes)\t%s\n",
-		       (change * 100) / (double) original_size, change, name);
+#if 0
+	if (opt_verbose) {
+	    printf("%6.2f%% (%+d bytes)\t%s\n",
+		    (change * 100) / (double) original_size, change, entry->name);
 	}
+#endif
 
 	return curr;
 }
@@ -644,7 +771,7 @@
 				set_data_offset(entry, base, offset);
 				entry->offset = offset;
 				map_entry(entry);
-				offset = do_compress(base, offset, entry->name, entry->uncompressed, entry->size);
+				offset = do_compress(base, offset, entry);
 				unmap_entry(entry);
 			}
 		}
@@ -660,13 +787,10 @@
 	int fd;
 	char *buf;
 
-	fd = open(file, O_RDONLY);
-	if (fd < 0) {
-		die(MKFS_ERROR, 1, "open failed: %s", file);
-	}
+	fd = xopen(file, O_RDONLY, 0);
 	buf = mmap(NULL, image_length, PROT_READ, MAP_PRIVATE, fd, 0);
 	if (buf == MAP_FAILED) {
-		die(MKFS_ERROR, 1, "mmap failed");
+		error_msg_and_die("mmap failed");
 	}
 	memcpy(base + offset, buf, image_length);
 	munmap(buf, image_length);
@@ -679,6 +803,328 @@
 	return (offset + image_length);
 }
 
+static struct entry *find_filesystem_entry(struct entry *dir, char *name, mode_t type)
+{
+	struct entry *e = dir;
+
+	if (S_ISDIR(dir->mode)) {
+		e = dir->child;
+	}
+	while (e) {
+		/* Only bother to do the expensive strcmp on matching file types */
+		if (type == (e->mode & S_IFMT) && e->name) {
+			if (S_ISDIR(e->mode)) {
+				int len = strlen(e->name);
+
+				/* Check if we are a parent of the correct path */
+				if (strncmp(e->name, name, len) == 0) {
+					/* Is this an _exact_ match? */
+					if (strcmp(name, e->name) == 0) {
+						return (e);
+					}
+					/* Looks like we found a parent of the correct path */
+					if (name[len] == '/') {
+						if (e->child) {
+							return (find_filesystem_entry (e, name + len + 1, type));
+						} else {
+							return NULL;
+						}
+					}
+				}
+			} else {
+				if (strcmp(name, e->name) == 0) {
+					return (e);
+				}
+			}
+		}
+		e = e->next;
+	}
+	return (NULL);
+}
+
+void modify_entry(char *full_path, unsigned long uid, unsigned long gid,