rpm2cpio: handle bz2 too; code shrink

function                                             old     new   delta
skip_header                                          142      99     -43
rpm2cpio_main                                        321     183    -138
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 0/2 up/down: 0/-181)           Total: -181 bytes

Signed-off-by: Pascal Bellard <pascal.bellard@ads-lu.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

2 files changed, 49 insertions, 30 deletions

diff --git a/archival/rpm2cpio.c b/archival/rpm2cpio.c
index ee938716f..566a9f213 100644
--- a/archival/rpm2cpio.c
+++ b/archival/rpm2cpio.c
@@ -9,11 +9,11 @@
 #include "libbb.h"
 #include "unarchive.h"
 
-#define RPM_MAGIC "\355\253\356\333"
-#define RPM_HEADER_MAGIC "\216\255\350"
+#define RPM_MAGIC            0xedabeedb
+#define RPM_MAGIC_STR        "\355\253\356\333"
 
 struct rpm_lead {
-	unsigned char magic[4];
+	uint32_t magic;
 	uint8_t major, minor;
 	uint16_t type;
 	uint16_t archnum;
@@ -23,67 +23,86 @@ struct rpm_lead {
 	char reserved[16];
 };
 
+#define RPM_HEADER_VERnMAGIC 0x8eade801
+#define RPM_HEADER_MAGIC_STR "\216\255\350"
+
 struct rpm_header {
-	char magic[3]; /* 3 byte magic: 0x8e 0xad 0xe8 */
-	uint8_t version; /* 1 byte version number */
+	uint32_t magic_and_ver; /* 3 byte magic: 0x8e 0xad 0xe8; 1 byte version */
 	uint32_t reserved; /* 4 bytes reserved */
 	uint32_t entries; /* Number of entries in header (4 bytes) */
 	uint32_t size; /* Size of store (4 bytes) */
 };
 
-static void skip_header(int rpm_fd)
+static off_t skip_header(int rpm_fd)
 {
 	struct rpm_header header;
 
-	xread(rpm_fd, &header, sizeof(struct rpm_header));
-	if (strncmp((char *) &header.magic, RPM_HEADER_MAGIC, 3) != 0) {
-		bb_error_msg_and_die("invalid RPM header magic"); /* Invalid magic */
-	}
-	if (header.version != 1) {
-		bb_error_msg_and_die("unsupported RPM header version"); /* This program only supports v1 headers */
+	xread(rpm_fd, &header, sizeof(header));
+//	if (strncmp((char *) &header.magic, RPM_HEADER_MAGIC_STR, 3) != 0) {
+//		bb_error_msg_and_die("invalid RPM header magic");
+//	}
+//	if (header.version != 1) {
+//		bb_error_msg_and_die("unsupported RPM header version");
+//	}
+	if (header.magic_and_ver != htonl(RPM_HEADER_VERnMAGIC)) {
+		bb_error_msg_and_die("invalid RPM header magic or unsupported version");
+		// ": %x != %x", header.magic_and_ver, htonl(RPM_HEADER_VERnMAGIC));
 	}
-	header.entries = ntohl(header.entries);
-	header.size = ntohl(header.size);
-	lseek (rpm_fd, 16 * header.entries, SEEK_CUR); /* Seek past index entries */
-	lseek (rpm_fd, header.size, SEEK_CUR); /* Seek past store */
+	/* Seek past index entries */
+	lseek(rpm_fd, 16 * ntohl(header.entries), SEEK_CUR);
+	/* Seek past store */
+	return lseek(rpm_fd, ntohl(header.size), SEEK_CUR);
 }
 
 /* No getopt required */
 int rpm2cpio_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
-int rpm2cpio_main(int argc, char **argv)
+int rpm2cpio_main(int argc UNUSED_PARAM, char **argv)
 {
 	struct rpm_lead lead;
 	int rpm_fd;
+	off_t pos;
 	unsigned char magic[2];
+	IF_DESKTOP(long long) int FAST_FUNC (*unpack)(int src_fd, int dst_fd);
 
-	if (argc == 1) {
+	if (!argv[1]) {
 		rpm_fd = STDIN_FILENO;
 	} else {
 		rpm_fd = xopen(argv[1], O_RDONLY);
 	}
+	xread(rpm_fd, &lead, sizeof(lead));
 
-	xread(rpm_fd, &lead, sizeof(struct rpm_lead));
-	if (strncmp((char *) &lead.magic, RPM_MAGIC, 4) != 0) {
-		bb_error_msg_and_die("invalid RPM magic"); /* Just check the magic, the rest is irrelevant */
+	/* Just check the magic, the rest is irrelevant */
+	if (lead.magic != htonl(RPM_MAGIC)) {
+		bb_error_msg_and_die("invalid RPM magic");
 	}
 
-	/* Skip the signature header */
-	skip_header(rpm_fd);
-	lseek(rpm_fd, (8 - (lseek(rpm_fd, 0, SEEK_CUR) % 8)) % 8, SEEK_CUR);
+	/* Skip the signature header, align to 8 bytes */
+	pos = skip_header(rpm_fd);
+	lseek(rpm_fd, (8 - (unsigned)pos) & 7, SEEK_CUR);
 
 	/* Skip the main header */
 	skip_header(rpm_fd);
 
 	xread(rpm_fd, &magic, 2);
-	if ((magic[0] != 0x1f) || (magic[1] != 0x8b)) {
-		bb_error_msg_and_die("invalid gzip magic");
+	unpack = unpack_gz_stream;
+	if (magic[0] != 0x1f || magic[1] != 0x8b) {
+		if (!ENABLE_FEATURE_SEAMLESS_BZ2
+		 || magic[0] != 'B' || magic[1] != 'Z'
+		) {
+			bb_error_msg_and_die("invalid gzip"
+					IF_FEATURE_SEAMLESS_BZ2("/bzip2")
+					" magic");
+		}
+		unpack = unpack_bz2_stream;
 	}
 
-	if (unpack_gz_stream(rpm_fd, STDOUT_FILENO) < 0) {
-		bb_error_msg("error inflating");
+	if (unpack(rpm_fd, STDOUT_FILENO) < 0) {
+		bb_error_msg_and_die("error unpacking");
 	}
 
-	close(rpm_fd);
+	if (ENABLE_FEATURE_CLEAN_UP) {
+		close(rpm_fd);
+	}
 
 	return 0;
 }
diff --git a/libbb/read.c b/libbb/read.c
index b58982b32..b93a695b5 100644
--- a/libbb/read.c
+++ b/libbb/read.c
@@ -336,7 +336,7 @@ int FAST_FUNC open_zipped(const char *fname)
 		 || (ENABLE_FEATURE_SEAMLESS_BZ2 && strcmp(sfx, ".bz2") == 0)
 		) {
 			/* .gz and .bz2 both have 2-byte signature, and their
-			 * unpack_XXX_stream want this header skipped. */
+			 * unpack_XXX_stream wants this header skipped. */
 			xread(fd, &magic, 2);
 #if ENABLE_FEATURE_SEAMLESS_GZ
 #if BB_MMU