unsquashfs: add code to unpack the entire file system

Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>

1 files changed, 105 insertions, 0 deletions

diff --git a/unpack/restore_fstree.c b/unpack/restore_fstree.c
new file mode 100644
index 0000000..56c3cc5
--- /dev/null
+++ b/unpack/restore_fstree.c
@@ -0,0 +1,105 @@
+/* SPDX-License-Identifier: GPL-3.0-or-later */
+#include "unsquashfs.h"
+
+static int restore_directory(int dirfd, tree_node_t *n, compressor_t *cmp,
+			     size_t block_size, frag_reader_t *frag,
+			     int sqfsfd)
+{
+	int fd;
+
+	for (n = n->data.dir->children; n != NULL; n = n->next) {
+		switch (n->mode & S_IFMT) {
+		case S_IFDIR:
+			if (mkdirat(dirfd, n->name, n->mode) &&
+			    errno != EEXIST) {
+				fprintf(stderr, "mkdir %s: %s\n",
+					n->name, strerror(errno));
+				return -1;
+			}
+
+			fd = openat(dirfd, n->name, O_RDONLY | O_DIRECTORY);
+			if (fd < 0) {
+				fprintf(stderr, "open dir %s: %s\n",
+					n->name, strerror(errno));
+				return -1;
+			}
+
+			if (restore_directory(fd, n, cmp, block_size,
+					      frag, sqfsfd)) {
+				close(fd);
+				return -1;
+			}
+
+			close(fd);
+			break;
+		case S_IFLNK:
+			if (symlinkat(n->data.slink_target, dirfd, n->name)) {
+				fprintf(stderr, "ln -s %s %s: %s\n",
+					n->data.slink_target, n->name,
+					strerror(errno));
+				return -1;
+			}
+			break;
+		case S_IFSOCK:
+		case S_IFIFO:
+			if (mknodat(dirfd, n->name, n->mode, 0)) {
+				fprintf(stderr, "creating %s: %s\n",
+					n->name, strerror(errno));
+				return -1;
+			}
+			break;
+		case S_IFBLK:
+		case S_IFCHR:
+			if (mknodat(dirfd, n->name, n->mode, n->data.devno)) {
+				fprintf(stderr, "creating device %s: %s\n",
+					n->name, strerror(errno));
+				return -1;
+			}
+			break;
+		case S_IFREG:
+			fd = openat(dirfd, n->name,
+				    O_WRONLY | O_CREAT | O_EXCL, n->mode);
+			if (fd < 0) {
+				fprintf(stderr, "creating %s: %s\n",
+					n->name, strerror(errno));
+				return -1;
+			}
+
+			if (extract_file(n->data.file, cmp, block_size,
+					 frag, sqfsfd, fd)) {
+				close(fd);
+				return -1;
+			}
+
+			close(fd);
+			break;
+		default:
+			break;
+		}
+	}
+
+	return 0;
+}
+
+int restore_fstree(const char *rootdir, tree_node_t *root, compressor_t *cmp,
+		   size_t block_size, frag_reader_t *frag, int sqfsfd)
+{
+	int dirfd;
+
+	if (mkdir_p(rootdir))
+		return -1;
+
+	dirfd = open(rootdir, O_RDONLY | O_DIRECTORY);
+	if (dirfd < 0) {
+		perror(rootdir);
+		return -1;
+	}
+
+	if (restore_directory(dirfd, root, cmp, block_size, frag, sqfsfd)) {
+		close(dirfd);
+		return -1;
+	}
+
+	close(dirfd);
+	return 0;
+}