extract: new applet to extract v2 packages

1 files changed, 239 insertions, 0 deletions

diff --git a/src/app_extract.c b/src/app_extract.c
new file mode 100644
index 0000000..acee37b
--- /dev/null
+++ b/src/app_extract.c
@@ -0,0 +1,239 @@
+/* extract.c - Alpine Package Keeper (APK)
+ *
+ * Copyright (C) 2008-2021 Timo Teräs <timo.teras@iki.fi>
+ * All rights reserved.
+ *
+ * SPDX-License-Identifier: GPL-2.0-only
+ */
+
+#include <errno.h>
+#include <stdio.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <sys/stat.h>
+
+#include "apk_applet.h"
+#include "apk_print.h"
+#include "apk_adb.h"
+#include "apk_pathbuilder.h"
+
+struct extract_ctx {
+	const char *destination;
+	unsigned int extract_flags;
+
+	struct apk_ctx *ac;
+	struct adb db;
+	int root_fd;
+
+	struct adb_obj pkg, paths, path, files, file;
+	unsigned int cur_path, cur_file;
+
+	struct apk_pathbuilder pb;
+};
+
+
+#define EXTRACT_OPTIONS(OPT) \
+	OPT(OPT_EXTRACT_destination,	APK_OPT_ARG "destination") \
+	OPT(OPT_EXTRACT_no_chown,	"no-chown")
+
+APK_OPT_APPLET(option_desc, EXTRACT_OPTIONS);
+
+static int option_parse_applet(void *pctx, struct apk_ctx *ac, int opt, const char *optarg)
+{
+	struct extract_ctx *ctx = (struct extract_ctx *) pctx;
+
+	switch (opt) {
+	case OPT_EXTRACT_destination:
+		ctx->destination = optarg;
+		break;
+	case OPT_EXTRACT_no_chown:
+		ctx->extract_flags |= APK_EXTRACTF_NO_CHOWN;
+		break;
+	default:
+		return -ENOTSUP;
+	}
+	return 0;
+}
+
+static const struct apk_option_group optgroup_applet = {
+	.desc = option_desc,
+	.parse = option_parse_applet,
+};
+
+static void apk_extract_acl(struct apk_file_info *fi, struct adb_obj *o, struct apk_id_cache *idc)
+{
+	fi->mode = adb_ro_int(o, ADBI_ACL_MODE);
+	fi->uid = apk_id_cache_resolve_uid(idc, adb_ro_blob(o, ADBI_ACL_USER), 65534);
+	fi->gid = apk_id_cache_resolve_gid(idc, adb_ro_blob(o, ADBI_ACL_GROUP), 65534);
+}
+
+static int apk_extract_file(struct extract_ctx *ctx, off_t sz, struct apk_istream *is)
+{
+	struct apk_ctx *ac = ctx->ac;
+	struct apk_out *out = &ac->out;
+	struct apk_file_info fi = {
+		.name = apk_pathbuilder_cstr(&ctx->pb),
+		.size = adb_ro_int(&ctx->file, ADBI_FI_SIZE),
+		.mtime = adb_ro_int(&ctx->file, ADBI_FI_MTIME),
+	};
+	struct adb_obj acl;
+	struct apk_digest_ctx dctx;
+	struct apk_digest d;
+	int r;
+
+	apk_digest_from_blob(&fi.digest, adb_ro_blob(&ctx->file, ADBI_FI_HASHES));
+	if (fi.digest.alg == APK_DIGEST_NONE) return -EAPKFORMAT;
+	apk_extract_acl(&fi, adb_ro_obj(&ctx->file, ADBI_FI_ACL, &acl), apk_ctx_get_id_cache(ctx->ac));
+	fi.mode |= S_IFREG;
+
+	apk_digest_ctx_init(&dctx, fi.digest.alg);
+	r = apk_archive_entry_extract(
+		ctx->root_fd, &fi, 0, 0, is, 0, 0, &dctx,
+		ctx->extract_flags, out);
+	apk_digest_ctx_final(&dctx, &d);
+	apk_digest_ctx_free(&dctx);
+	if (r != 0) return r;
+	if (apk_digest_cmp(&fi.digest, &d) != 0) return -EAPKDBFORMAT;
+	return 0;
+}
+
+static int apk_extract_directory(struct extract_ctx *ctx)
+{
+	struct apk_ctx *ac = ctx->ac;
+	struct apk_out *out = &ac->out;
+	struct apk_file_info fi = {
+		.name = apk_pathbuilder_cstr(&ctx->pb),
+	};
+	struct adb_obj acl;
+
+	apk_extract_acl(&fi, adb_ro_obj(&ctx->path, ADBI_DI_ACL, &acl), apk_ctx_get_id_cache(ctx->ac));
+	fi.mode |= S_IFDIR;
+
+	return apk_archive_entry_extract(
+		ctx->root_fd, &fi, 0, 0, 0, 0, 0, 0,
+		ctx->extract_flags, out);
+}
+
+static int apk_extract_next_file(struct extract_ctx *ctx)
+{
+	apk_blob_t target;
+	int r;
+
+	if (!ctx->cur_path) {
+		// one time init
+		ctx->cur_path = ADBI_FIRST;
+		ctx->cur_file = 0;
+		adb_r_rootobj(&ctx->db, &ctx->pkg, &schema_package);
+		adb_ro_obj(&ctx->pkg, ADBI_PKG_PATHS, &ctx->paths);
+		adb_ro_obj(&ctx->paths, ctx->cur_path, &ctx->path);
+		adb_ro_obj(&ctx->path, ADBI_DI_FILES, &ctx->files);
+	}
+
+	do {
+		ctx->cur_file++;
+		while (ctx->cur_file > adb_ra_num(&ctx->files)) {
+			ctx->cur_path++;
+			ctx->cur_file = ADBI_FIRST;
+			if (ctx->cur_path > adb_ra_num(&ctx->paths)) return 1;
+			adb_ro_obj(&ctx->paths, ctx->cur_path, &ctx->path);
+			apk_pathbuilder_setb(&ctx->pb, adb_ro_blob(&ctx->path, ADBI_DI_NAME));
+			adb_ro_obj(&ctx->path, ADBI_DI_FILES, &ctx->files);
+			r = apk_extract_directory(ctx);
+			if (r != 0) return r;
+		}
+		adb_ro_obj(&ctx->files, ctx->cur_file, &ctx->file);
+		apk_pathbuilder_setb(&ctx->pb, adb_ro_blob(&ctx->path, ADBI_DI_NAME));
+		apk_pathbuilder_pushb(&ctx->pb, adb_ro_blob(&ctx->file, ADBI_FI_NAME));
+		target = adb_ro_blob(&ctx->file, ADBI_FI_TARGET);
+		if (adb_ro_int(&ctx->file, ADBI_FI_SIZE) != 0 &&
+		    APK_BLOB_IS_NULL(target)) {
+			return 0;
+		}
+		r = apk_extract_file(ctx, 0, 0);
+		if (r != 0) return r;
+	} while (1);
+}
+
+static int apk_extract_data_block(struct adb *db, size_t sz, struct apk_istream *is)
+{
+	struct extract_ctx *ctx = container_of(db, struct extract_ctx, db);
+	struct adb_data_package *hdr;
+	int r;
+
+	r = apk_extract_next_file(ctx);
+	if (r != 0) {
+		if (r > 0) r = -EAPKFORMAT;
+		return r;
+	}
+
+	hdr = apk_istream_get(is, sizeof *hdr);
+	sz -= sizeof *hdr;
+	if (IS_ERR(hdr)) return PTR_ERR(hdr);
+
+	if (hdr->path_idx != ctx->cur_path ||
+	    hdr->file_idx != ctx->cur_file ||
+	    sz != adb_ro_int(&ctx->file, ADBI_FI_SIZE)) {
+		// got data for some unexpected file
+		return -EAPKFORMAT;
+	}
+
+	return apk_extract_file(ctx, sz, is);
+}
+
+static int apk_extract_pkg(struct extract_ctx *ctx, const char *fn)
+{
+	struct apk_ctx *ac = ctx->ac;
+	struct apk_trust *trust = apk_ctx_get_trust(ac);
+	int r;
+
+	r = adb_m_stream(&ctx->db,
+		apk_istream_gunzip(apk_istream_from_fd_url(AT_FDCWD, fn, apk_ctx_since(ac, 0))),
+		ADB_SCHEMA_PACKAGE, trust, apk_extract_data_block);
+	if (r == 0) {
+		r = apk_extract_next_file(ctx);
+		if (r == 0) r = -EAPKFORMAT;
+		if (r == 1) r = 0;
+	}
+	adb_free(&ctx->db);
+	return r;
+}
+
+static int extract_main(void *pctx, struct apk_ctx *ac, struct apk_string_array *args)
+{
+	struct extract_ctx *ctx = pctx;
+	struct apk_out *out = &ac->out;
+	char **parg;
+	int r;
+
+	ctx->ac = ac;
+	ctx->extract_flags |= APK_EXTRACTF_NO_OVERWRITE;
+	if (!ctx->destination) ctx->destination = ".";
+	ctx->root_fd = openat(AT_FDCWD, ctx->destination, O_RDONLY);
+	if (ctx->root_fd < 0) {
+		r = -errno;
+		apk_err(out, "Error opening destination '%s': %s",
+			ctx->destination, apk_error_str(r));
+		return r;
+	}
+
+	foreach_array_item(parg, args) {
+		apk_out(out, "Extracting %s...", *parg);
+		r = apk_extract_pkg(ctx, *parg);
+		if (r != 0) {
+			apk_err(out, "%s: %s", *parg, apk_error_str(r));
+			break;
+		}
+	}
+	close(ctx->root_fd);
+	return r;
+}
+
+static struct apk_applet apk_extract = {
+	.name = "extract",
+	.context_size = sizeof(struct extract_ctx),
+	.optgroups = { &optgroup_global, &optgroup_applet },
+	.main = extract_main,
+};
+
+APK_DEFINE_APPLET(apk_extract);
+