Cleanup: try to split sqfs2tar.c in a reasonable way

This comit breaks sqfs2tar into multiple files:
 - options.c contains the command line argument processing
 - write_tree.c contains the code for generating the actual tar archive
 - sqfs2tar.c contains what is left
 - A header is added for glueing it all together.

No actual code is changed.

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

1 files changed, 192 insertions, 0 deletions

diff --git a/bin/sqfs2tar/options.c b/bin/sqfs2tar/options.c
new file mode 100644
index 0000000..e5c8319
--- /dev/null
+++ b/bin/sqfs2tar/options.c
@@ -0,0 +1,192 @@
+/* SPDX-License-Identifier: GPL-3.0-or-later */
+/*
+ * options.c
+ *
+ * Copyright (C) 2019 David Oberhollenzer <goliath@infraroot.at>
+ */
+#include "sqfs2tar.h"
+
+static struct option long_opts[] = {
+	{ "subdir", required_argument, NULL, 'd' },
+	{ "keep-as-dir", no_argument, NULL, 'k' },
+	{ "root-becomes", required_argument, NULL, 'r' },
+	{ "no-skip", no_argument, NULL, 's' },
+	{ "no-xattr", no_argument, NULL, 'X' },
+	{ "no-hard-links", no_argument, NULL, 'L' },
+	{ "help", no_argument, NULL, 'h' },
+	{ "version", no_argument, NULL, 'V' },
+	{ NULL, 0, NULL, 0 },
+};
+
+static const char *short_opts = "d:kr:sXLhV";
+
+static const char *usagestr =
+"Usage: sqfs2tar [OPTIONS...] <sqfsfile>\n"
+"\n"
+"Read an input squashfs archive and turn it into a tar archive, written\n"
+"to stdout.\n"
+"\n"
+"Possible options:\n"
+"\n"
+"  --subdir, -d <dir>        Unpack the given sub directory instead of the\n"
+"                            filesystem root. Can be specified more than\n"
+"                            once to select multiple directories. If only\n"
+"                            one is specified, it becomes the new root of\n"
+"                            node of the archive file system tree.\n"
+"\n"
+"  --root-becomes, -r <dir>  Turn the root inode into a directory with the\n"
+"                            specified name. Everything else will be stored\n"
+"                            inside this directory. The special value '.' is\n"
+"                            allowed to prefix all tar paths with './' and\n"
+"                            add an entry named '.' for the root inode.\n"
+"                            If this option isn't used, all meta data stored\n"
+"                            in the root inode IS LOST!\n"
+"\n"
+"  --keep-as-dir, -k         If --subdir is used only once, don't make the\n"
+"                            subdir the archive root, instead keep it as\n"
+"                            prefix for all unpacked files.\n"
+"                            Using --subdir more than once implies\n"
+"                            --keep-as-dir.\n"
+"  --no-xattr, -X            Do not copy extended attributes.\n"
+"  --no-hard-links, -L       Do not generate hard links. Produce duplicate\n"
+"                            entries instead.\n"
+"\n"
+"  --no-skip, -s             Abort if a file cannot be stored in a tar\n"
+"                            archive. By default, it is simply skipped\n"
+"                            and a warning is written to stderr.\n"
+"\n"
+"  --help, -h                Print help text and exit.\n"
+"  --version, -V             Print version information and exit.\n"
+"\n"
+"Examples:\n"
+"\n"
+"\tsqfs2tar rootfs.sqfs > rootfs.tar\n"
+"\tsqfs2tar rootfs.sqfs | gzip > rootfs.tar.gz\n"
+"\tsqfs2tar rootfs.sqfs | xz > rootfs.tar.xz\n"
+"\n";
+
+bool dont_skip = false;
+bool keep_as_dir = false;
+bool no_xattr = false;
+bool no_links = false;
+
+char *root_becomes = NULL;
+char **subdirs = NULL;
+size_t num_subdirs = 0;
+static size_t max_subdirs = 0;
+
+const char *filename = NULL;
+
+void process_args(int argc, char **argv)
+{
+	size_t idx, new_count;
+	int i, ret;
+	void *new;
+
+	for (;;) {
+		i = getopt_long(argc, argv, short_opts, long_opts, NULL);
+		if (i == -1)
+			break;
+
+		switch (i) {
+		case 'd':
+			if (num_subdirs == max_subdirs) {
+				new_count = max_subdirs ? max_subdirs * 2 : 16;
+				new = realloc(subdirs,
+					      new_count * sizeof(subdirs[0]));
+				if (new == NULL)
+					goto fail_errno;
+
+				max_subdirs = new_count;
+				subdirs = new;
+			}
+
+			subdirs[num_subdirs] = strdup(optarg);
+			if (subdirs[num_subdirs] == NULL)
+				goto fail_errno;
+
+			if (canonicalize_name(subdirs[num_subdirs])) {
+				perror(optarg);
+				goto fail;
+			}
+
+			++num_subdirs;
+			break;
+		case 'r':
+			free(root_becomes);
+			root_becomes = strdup(optarg);
+			if (root_becomes == NULL)
+				goto fail_errno;
+
+			if (strcmp(root_becomes, "./") == 0)
+				root_becomes[1] = '\0';
+
+			if (strcmp(root_becomes, ".") == 0)
+				break;
+
+			if (canonicalize_name(root_becomes) != 0 ||
+			    strlen(root_becomes) == 0) {
+				fprintf(stderr,
+					"Invalid root directory '%s'.\n",
+					optarg);
+				goto fail_arg;
+			}
+			break;
+		case 'k':
+			keep_as_dir = true;
+			break;
+		case 's':
+			dont_skip = true;
+			break;
+		case 'X':
+			no_xattr = true;
+			break;
+		case 'L':
+			no_links = true;
+			break;
+		case 'h':
+			fputs(usagestr, stdout);
+			goto out_success;
+		case 'V':
+			print_version("sqfs2tar");
+			goto out_success;
+		default:
+			goto fail_arg;
+		}
+	}
+
+	if (optind >= argc) {
+		fputs("Missing argument: squashfs image\n", stderr);
+		goto fail_arg;
+	}
+
+	filename = argv[optind++];
+
+	if (optind < argc) {
+		fputs("Unknown extra arguments\n", stderr);
+		goto fail_arg;
+	}
+
+	if (num_subdirs > 1)
+		keep_as_dir = true;
+
+	return;
+fail_errno:
+	perror("parsing options");
+	goto fail;
+fail_arg:
+	fputs("Try `sqfs2tar --help' for more information.\n", stderr);
+	goto fail;
+fail:
+	ret = EXIT_FAILURE;
+	goto out_exit;
+out_success:
+	ret = EXIT_SUCCESS;
+	goto out_exit;
+out_exit:
+	for (idx = 0; idx < num_subdirs; ++idx)
+		free(subdirs[idx]);
+	free(root_becomes);
+	free(subdirs);
+	exit(ret);
+}