12 files changed, 145 insertions, 193 deletions

diff --git a/archival/Config.in b/archival/Config.in
index b26be6486..d6332a2b2 100644
--- a/archival/Config.in
+++ b/archival/Config.in
@@ -5,6 +5,30 @@
 
 menu "Archival Utilities"
 
+config FEATURE_SEAMLESS_LZMA
+        bool "Make tar, rpm, man, modprobe etc understand .lzma data"
+        default n
+        help
+          Make tar, rpm, man, modprobe etc understand .lzma data.
+
+config FEATURE_SEAMLESS_BZ2
+        bool "Make tar, rpm, man, modprobe etc understand .bz2 data"
+        default n
+        help
+          Make tar, rpm, man, modprobe etc understand .bz2 data.
+
+config FEATURE_SEAMLESS_GZ
+        bool "Make tar, rpm, man, modprobe etc understand .gz data"
+        default n
+        help
+          Make tar, rpm, man, modprobe etc understand .gz data.
+
+config FEATURE_SEAMLESS_Z
+        bool "Make tar and gunzip understand .Z data"
+        default n
+        help
+          Make tar and gunzip understand .Z data.
+
 config AR
         bool "ar"
         default n
@@ -126,15 +150,6 @@ config GUNZIP
           You can use the `-t' option to test the integrity of
           an archive, without decompressing it.
 
-config FEATURE_GUNZIP_UNCOMPRESS
-        bool "Uncompress support"
-        default n
-        depends on GUNZIP
-        help
-          Enable if you want gunzip to have the ability to decompress
-          archives created by the program compress (not much
-          used anymore).
-
 config GZIP
         bool "gzip"
         default n
@@ -154,13 +169,6 @@ config RPM
         help
           Mini RPM applet - queries and extracts RPM packages.
 
-config FEATURE_RPM_BZ2
-        bool "Enable handling of rpms with bzip2-compressed data inside"
-        default n
-        depends on RPM
-        help
-          Enable handling of rpms with bzip2-compressed data inside.
-
 config TAR
         bool "tar"
         default n
@@ -179,42 +187,10 @@ config FEATURE_TAR_CREATE
           If you enable this option you'll be able to create
           tar archives using the `-c' option.
 
-config FEATURE_TAR_GZIP
-        bool "Enable -z option"
-        default y
-        depends on TAR
-        help
-          If you enable this option tar will be able to call gzip,
-          when creating or extracting tar gziped archives.
-
-config FEATURE_TAR_BZIP2
-        bool "Enable -j option to handle .tar.bz2 files"
-        default n
-        depends on TAR
-        help
-          If you enable this option you'll be able to extract
-          archives compressed with bzip2.
-
-config FEATURE_TAR_LZMA
-        bool "Enable -a option to handle .tar.lzma files"
-        default n
-        depends on TAR
-        help
-          If you enable this option you'll be able to extract
-          archives compressed with lzma.
-
-config FEATURE_TAR_COMPRESS
-        bool "Enable -Z option"
-        default n
-        depends on TAR
-        help
-          If you enable this option tar will be able to call uncompress,
-          when extracting .tar.Z archives.
-
 config FEATURE_TAR_AUTODETECT
-        bool "Autodetect gz/bz2 compresses tarballs"
+        bool "Autodetect gz/bz2 compressed tarballs"
         default n
-        depends on FEATURE_TAR_GZIP || FEATURE_TAR_BZIP2
+        depends on FEATURE_SEAMLESS_Z || FEATURE_SEAMLESS_GZ || FEATURE_SEAMLESS_BZ2 || FEATURE_SEAMLESS_LZMA
         help
           With this option tar can automatically detect gzip/bzip2 compressed
           tarballs. Currently it works only on files (not pipes etc).
@@ -312,42 +288,4 @@ config UNZIP
           current directory. Use the `-d' option to extract to a
           directory of your choice.
 
-comment "Common options for cpio and tar"
-        depends on CPIO || TAR
-
-comment "Common options for dpkg and dpkg_deb"
-        depends on DPKG || DPKG_DEB
-
-config FEATURE_DEB_TAR_GZ
-        bool "gzip debian packages (normal)"
-        default y if DPKG || DPKG_DEB
-        depends on DPKG || DPKG_DEB
-        help
-          This is the default compression method inside the debian ar file.
-
-          If you want compatibility with standard .deb's you should say yes
-          here.
-
-config FEATURE_DEB_TAR_BZ2
-        bool "bzip2 debian packages"
-        default n
-        depends on DPKG || DPKG_DEB
-        help
-          This allows dpkg and dpkg-deb to extract deb's that are compressed
-          internally with bzip2 instead of gzip.
-
-          You only want this if you are creating your own custom debian
-          packages that use an internal control.tar.bz2 or data.tar.bz2.
-
-config FEATURE_DEB_TAR_LZMA
-        bool "lzma debian packages"
-        default n
-        depends on DPKG || DPKG_DEB
-        help
-          This allows dpkg and dpkg-deb to extract deb's that are compressed
-          internally with lzma instead of gzip.
-
-          You only want this if you are creating your own custom debian
-          packages that use an internal control.tar.lzma or data.tar.lzma.
-
 endmenu
diff --git a/archival/bbunzip.c b/archival/bbunzip.c
index 65bb8b7f4..c7962058e 100644
--- a/archival/bbunzip.c
+++ b/archival/bbunzip.c
@@ -161,7 +161,7 @@ char* make_new_name_bunzip2(char *filename)
 static
 USE_DESKTOP(long long) int unpack_bunzip2(void)
 {
-        return unpack_bz2_stream(STDIN_FILENO, STDOUT_FILENO);
+        return unpack_bz2_stream_prime(STDIN_FILENO, STDOUT_FILENO);
 }
 
 int bunzip2_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
@@ -218,8 +218,8 @@ char* make_new_name_gunzip(char *filename)
 
         extension++;
         if (strcmp(extension, "tgz" + 1) == 0
-#if ENABLE_FEATURE_GUNZIP_UNCOMPRESS
-         || strcmp(extension, "Z") == 0
+#if ENABLE_FEATURE_SEAMLESS_Z
+         || (extension[0] == 'Z' && extension[1] == '\0')
 #endif
         ) {
                 extension[-1] = '\0';
@@ -244,8 +244,8 @@ USE_DESKTOP(long long) int unpack_gunzip(void)
                 unsigned char magic2;
 
                 magic2 = xread_char(STDIN_FILENO);
-                if (ENABLE_FEATURE_GUNZIP_UNCOMPRESS && magic2 == 0x9d) {
-                        status = uncompress(STDIN_FILENO, STDOUT_FILENO);
+                if (ENABLE_FEATURE_SEAMLESS_Z && magic2 == 0x9d) {
+                        status = unpack_Z_stream(STDIN_FILENO, STDOUT_FILENO);
                 } else if (magic2 == 0x8b) {
                         status = unpack_gz_stream(STDIN_FILENO, STDOUT_FILENO);
                 } else {
@@ -351,7 +351,7 @@ USE_DESKTOP(long long) int unpack_uncompress(void)
         if ((xread_char(STDIN_FILENO) != 0x1f) || (xread_char(STDIN_FILENO) != 0x9d)) {
                 bb_error_msg("invalid magic");
         } else {
-                status = uncompress(STDIN_FILENO, STDOUT_FILENO);
+                status = unpack_Z_stream(STDIN_FILENO, STDOUT_FILENO);
         }
         return status;
 }
diff --git a/archival/dpkg.c b/archival/dpkg.c
index 54e963233..f31a7f017 100644
--- a/archival/dpkg.c
+++ b/archival/dpkg.c
@@ -1438,10 +1438,10 @@ static void init_archive_deb_control(archive_handle_t *ar_handle)
         tar_handle->src_fd = ar_handle->src_fd;
 
         /* We don't care about data.tar.* or debian-binary, just control.tar.* */
-#if ENABLE_FEATURE_DEB_TAR_GZ
+#if ENABLE_FEATURE_SEAMLESS_GZ
         llist_add_to(&(ar_handle->accept), (char*)"control.tar.gz");
 #endif
-#if ENABLE_FEATURE_DEB_TAR_BZ2
+#if ENABLE_FEATURE_SEAMLESS_BZ2
         llist_add_to(&(ar_handle->accept), (char*)"control.tar.bz2");
 #endif
 
@@ -1458,10 +1458,10 @@ static void init_archive_deb_data(archive_handle_t *ar_handle)
         tar_handle->src_fd = ar_handle->src_fd;
 
         /* We don't care about control.tar.* or debian-binary, just data.tar.* */
-#if ENABLE_FEATURE_DEB_TAR_GZ
+#if ENABLE_FEATURE_SEAMLESS_GZ
         llist_add_to(&(ar_handle->accept), (char*)"data.tar.gz");
 #endif
-#if ENABLE_FEATURE_DEB_TAR_BZ2
+#if ENABLE_FEATURE_SEAMLESS_BZ2
         llist_add_to(&(ar_handle->accept), (char*)"data.tar.bz2");
 #endif
 
diff --git a/archival/dpkg_deb.c b/archival/dpkg_deb.c
index 9e6340fd3..f94c90c55 100644
--- a/archival/dpkg_deb.c
+++ b/archival/dpkg_deb.c
@@ -31,12 +31,12 @@ int dpkg_deb_main(int argc, char **argv)
         ar_archive->sub_archive = tar_archive;
         ar_archive->filter = filter_accept_list_reassign;
 
-#if ENABLE_FEATURE_DEB_TAR_GZ
+#if ENABLE_FEATURE_SEAMLESS_GZ
         llist_add_to(&(ar_archive->accept), (char*)"data.tar.gz");
         llist_add_to(&control_tar_llist, (char*)"control.tar.gz");
 #endif
 
-#if ENABLE_FEATURE_DEB_TAR_BZ2
+#if ENABLE_FEATURE_SEAMLESS_BZ2
         llist_add_to(&(ar_archive->accept), (char*)"data.tar.bz2");
         llist_add_to(&control_tar_llist, (char*)"control.tar.bz2");
 #endif
diff --git a/archival/libunarchive/Kbuild b/archival/libunarchive/Kbuild
index 468a7e82a..364f9174c 100644
--- a/archival/libunarchive/Kbuild
+++ b/archival/libunarchive/Kbuild
@@ -32,36 +32,20 @@ DPKG_FILES:= \
         get_header_tar.o \
         filter_accept_list_reassign.o
 
-lib-$(CONFIG_RPM)                       += open_transformer.o
-lib-$(CONFIG_FEATURE_TAR_BZIP2)         += open_transformer.o
-lib-$(CONFIG_FEATURE_TAR_LZMA)          += open_transformer.o
-lib-$(CONFIG_FEATURE_TAR_GZIP)          += open_transformer.o
-lib-$(CONFIG_FEATURE_TAR_COMPRESS)      += open_transformer.o
-lib-$(CONFIG_FEATURE_DEB_TAR_GZ)        += open_transformer.o
-lib-$(CONFIG_FEATURE_DEB_TAR_BZ2)       += open_transformer.o
-lib-$(CONFIG_FEATURE_DEB_TAR_LZMA)      += open_transformer.o
-
-lib-$(CONFIG_FEATURE_MODPROBE_SMALL_ZIPPED) += open_transformer.o decompress_unzip.o decompress_bunzip2.o
-
 lib-$(CONFIG_AR)                        += get_header_ar.o unpack_ar_archive.o
 lib-$(CONFIG_BUNZIP2)                   += decompress_bunzip2.o
 lib-$(CONFIG_UNLZMA)                    += decompress_unlzma.o
 lib-$(CONFIG_CPIO)                      += get_header_cpio.o
 lib-$(CONFIG_DPKG)                      += $(DPKG_FILES)
 lib-$(CONFIG_DPKG_DEB)                  += $(DPKG_FILES)
-lib-$(CONFIG_FEATURE_DEB_TAR_GZ)        += decompress_unzip.o get_header_tar_gz.o
-lib-$(CONFIG_FEATURE_DEB_TAR_BZ2)       += decompress_bunzip2.o get_header_tar_bz2.o
-lib-$(CONFIG_FEATURE_DEB_TAR_LZMA)      += decompress_unlzma.o get_header_tar_lzma.o
 lib-$(CONFIG_GUNZIP)                    += decompress_unzip.o
-lib-$(CONFIG_FEATURE_GUNZIP_UNCOMPRESS) += decompress_uncompress.o
 lib-$(CONFIG_RPM2CPIO)                  += decompress_unzip.o get_header_cpio.o
-lib-$(CONFIG_RPM)                       += decompress_unzip.o get_header_cpio.o
-lib-$(CONFIG_FEATURE_RPM_BZ2)           += decompress_bunzip2.o
+lib-$(CONFIG_RPM)                       += open_transformer.o decompress_unzip.o get_header_cpio.o
 lib-$(CONFIG_TAR)                       += get_header_tar.o
-lib-$(CONFIG_FEATURE_TAR_BZIP2)         += decompress_bunzip2.o get_header_tar_bz2.o
-lib-$(CONFIG_FEATURE_TAR_LZMA)          += decompress_unlzma.o get_header_tar_lzma.o
-lib-$(CONFIG_FEATURE_TAR_GZIP)          += decompress_unzip.o get_header_tar_gz.o
-lib-$(CONFIG_FEATURE_TAR_COMPRESS)      += decompress_uncompress.o
 lib-$(CONFIG_UNCOMPRESS)                += decompress_uncompress.o
 lib-$(CONFIG_UNZIP)                     += decompress_unzip.o
+lib-$(CONFIG_FEATURE_SEAMLESS_Z)        += open_transformer.o decompress_uncompress.o
+lib-$(CONFIG_FEATURE_SEAMLESS_GZ)       += open_transformer.o decompress_unzip.o get_header_tar_gz.o
+lib-$(CONFIG_FEATURE_SEAMLESS_BZ2)      += open_transformer.o decompress_bunzip2.o get_header_tar_bz2.o
+lib-$(CONFIG_FEATURE_SEAMLESS_LZMA)     += open_transformer.o decompress_unlzma.o get_header_tar_lzma.o
 lib-$(CONFIG_FEATURE_COMPRESS_USAGE)    += decompress_bunzip2.o
diff --git a/archival/libunarchive/decompress_bunzip2.c b/archival/libunarchive/decompress_bunzip2.c
index 654dc28a9..b53720f23 100644
--- a/archival/libunarchive/decompress_bunzip2.c
+++ b/archival/libunarchive/decompress_bunzip2.c
@@ -590,7 +590,8 @@ int FAST_FUNC start_bunzip(bunzip_data **bdp, int in_fd, const unsigned char *in
         bunzip_data *bd;
         unsigned i;
         enum {
-                BZh0 = ('B' << 24) + ('Z' << 16) + ('h' << 8) + '0'
+                BZh0 = ('B' << 24) + ('Z' << 16) + ('h' << 8) + '0',
+                h0 = ('h' << 8) + '0',
         };
 
         /* Figure out how much data to allocate */
@@ -617,12 +618,18 @@ int FAST_FUNC start_bunzip(bunzip_data **bdp, int in_fd, const unsigned char *in
         if (i) return i;
 
         /* Ensure that file starts with "BZh['1'-'9']." */
-        i = get_bits(bd, 32);
-        if ((unsigned)(i - BZh0 - 1) >= 9) return RETVAL_NOT_BZIP_DATA;
+        /* Update: now caller verifies 1st two bytes, makes .gz/.bz2
+         * integration easier */
+        /* was: */
+        /* i = get_bits(bd, 32); */
+        /* if ((unsigned)(i - BZh0 - 1) >= 9) return RETVAL_NOT_BZIP_DATA; */
+        i = get_bits(bd, 16);
+        if ((unsigned)(i - h0 - 1) >= 9) return RETVAL_NOT_BZIP_DATA;
 
         /* Fourth byte (ascii '1'-'9') indicates block size in units of 100k of
            uncompressed data.  Allocate intermediate buffer for block. */
-        bd->dbufSize = 100000 * (i - BZh0);
+        /* bd->dbufSize = 100000 * (i - BZh0); */
+        bd->dbufSize = 100000 * (i - h0);
 
         /* Cannot use xmalloc - may leak bd in NOFORK case! */
         bd->dbuf = malloc_or_warn(bd->dbufSize * sizeof(int));
@@ -682,6 +689,17 @@ unpack_bz2_stream(int src_fd, int dst_fd)
         return i ? i : USE_DESKTOP(total_written) + 0;
 }
 
+USE_DESKTOP(long long) int FAST_FUNC
+unpack_bz2_stream_prime(int src_fd, int dst_fd)
+{
+        unsigned char magic[2];
+        xread(src_fd, magic, 2);
+        if (magic[0] != 'B' || magic[1] != 'Z') {
+                bb_error_msg_and_die("invalid magic");
+        }
+        return unpack_bz2_stream(src_fd, dst_fd);
+}
+
 #ifdef TESTING
 
 static char *const bunzip_errors[] = {
@@ -693,9 +711,10 @@ static char *const bunzip_errors[] = {
 /* Dumb little test thing, decompress stdin to stdout */
 int main(int argc, char **argv)
 {
-        int i = unpack_bz2_stream(0, 1);
+        int i;
         char c;
 
+        int i = unpack_bz2_stream_prime(0, 1);
         if (i < 0)
                 fprintf(stderr, "%s\n", bunzip_errors[-i]);
         else if (read(STDIN_FILENO, &c, 1))
diff --git a/archival/libunarchive/decompress_uncompress.c b/archival/libunarchive/decompress_uncompress.c
index 161570040..fe1491e71 100644
--- a/archival/libunarchive/decompress_uncompress.c
+++ b/archival/libunarchive/decompress_uncompress.c
@@ -1,6 +1,4 @@
 /* vi: set sw=4 ts=4: */
-#include "libbb.h"
-
 /* uncompress for busybox -- (c) 2002 Robert Griebl
  *
  * based on the original compress42.c source
@@ -26,6 +24,10 @@
  *
  */
 
+#include "libbb.h"
+#include "unarchive.h"
+
+
 /* Default input buffer size */
 #define IBUFSIZ 2048
 
@@ -71,7 +73,7 @@
  */
 
 USE_DESKTOP(long long) int FAST_FUNC
-uncompress(int fd_in, int fd_out)
+unpack_Z_stream(int fd_in, int fd_out)
 {
         USE_DESKTOP(long long total_written = 0;)
         USE_DESKTOP(long long) int retval = -1;
diff --git a/archival/libunarchive/filter_accept_list_reassign.c b/archival/libunarchive/filter_accept_list_reassign.c
index 4dbc2d13e..f1de4e803 100644
--- a/archival/libunarchive/filter_accept_list_reassign.c
+++ b/archival/libunarchive/filter_accept_list_reassign.c
@@ -23,22 +23,25 @@ char FAST_FUNC filter_accept_list_reassign(archive_handle_t *archive_handle)
 
                 /* Find extension */
                 name_ptr = strrchr(archive_handle->file_header->name, '.');
+                if (!name_ptr)
+                        return EXIT_FAILURE;
+                name_ptr++;
 
                 /* Modify the subarchive handler based on the extension */
-                if (ENABLE_FEATURE_DEB_TAR_GZ
-                 && strcmp(name_ptr, ".gz") == 0
+                if (ENABLE_FEATURE_SEAMLESS_GZ
+                 && strcmp(name_ptr, "gz") == 0
                 ) {
                         archive_handle->action_data_subarchive = get_header_tar_gz;
                         return EXIT_SUCCESS;
                 }
-                if (ENABLE_FEATURE_DEB_TAR_BZ2
-                 && strcmp(name_ptr, ".bz2") == 0
+                if (ENABLE_FEATURE_SEAMLESS_BZ2
+                 && strcmp(name_ptr, "bz2") == 0
                 ) {
                         archive_handle->action_data_subarchive = get_header_tar_bz2;
                         return EXIT_SUCCESS;
                 }
-                if (ENABLE_FEATURE_DEB_TAR_LZMA
-                 && strcmp(name_ptr, ".lzma") == 0
+                if (ENABLE_FEATURE_SEAMLESS_LZMA
+                 && strcmp(name_ptr, "lzma") == 0
                 ) {
                         archive_handle->action_data_subarchive = get_header_tar_lzma;
                         return EXIT_SUCCESS;
diff --git a/archival/libunarchive/get_header_tar.c b/archival/libunarchive/get_header_tar.c
index 5310f3f7c..bf0f92b25 100644
--- a/archival/libunarchive/get_header_tar.c
+++ b/archival/libunarchive/get_header_tar.c
@@ -148,12 +148,12 @@ char FAST_FUNC get_header_tar(archive_handle_t *archive_handle)
                  * we can switch to get_header_tar_gz/bz2/lzma().
                  * Needs seekable fd. I wish recv(MSG_PEEK) works
                  * on any fd... */
-#if ENABLE_FEATURE_TAR_GZIP
+#if ENABLE_FEATURE_SEAMLESS_GZ
                 if (tar.name[0] == 0x1f && tar.name[1] == (char)0x8b) { /* gzip */
                         get_header_ptr = get_header_tar_gz;
                 } else
 #endif
-#if ENABLE_FEATURE_TAR_BZIP2
+#if ENABLE_FEATURE_SEAMLESS_BZ2
                 if (tar.name[0] == 'B' && tar.name[1] == 'Z'
                  && tar.name[2] == 'h' && isdigit(tar.name[3])
                 ) { /* bzip2 */
diff --git a/archival/libunarchive/get_header_tar_bz2.c b/archival/libunarchive/get_header_tar_bz2.c
index 035c10bfb..615bbba4a 100644
--- a/archival/libunarchive/get_header_tar_bz2.c
+++ b/archival/libunarchive/get_header_tar_bz2.c
@@ -11,7 +11,7 @@ char FAST_FUNC get_header_tar_bz2(archive_handle_t *archive_handle)
         /* Can't lseek over pipes */
         archive_handle->seek = seek_by_read;
 
-        open_transformer(archive_handle->src_fd, unpack_bz2_stream, "bunzip2");
+        open_transformer(archive_handle->src_fd, unpack_bz2_stream_prime, "bunzip2");
         archive_handle->offset = 0;
         while (get_header_tar(archive_handle) == EXIT_SUCCESS)
                 continue;
diff --git a/archival/rpm.c b/archival/rpm.c
index e6dd3d853..e1f3c8930 100644
--- a/archival/rpm.c
+++ b/archival/rpm.c
@@ -206,27 +206,27 @@ static void extract_cpio_gz(int fd)
         archive_handle->src_fd = fd;
         /*archive_handle->offset = 0; - init_handle() did it */
 
+// TODO: open_zipped does the same
+
         xread(archive_handle->src_fd, &magic, 2);
 #if BB_MMU
         xformer = unpack_gz_stream;
 #else
         xformer_prog = "gunzip";
 #endif
-        if ((magic[0] != 0x1f) || (magic[1] != 0x8b)) {
-                if (ENABLE_FEATURE_RPM_BZ2
-                 && (magic[0] == 0x42) && (magic[1] == 0x5a)) {
+        if (magic[0] != 0x1f || magic[1] != 0x8b) {
+                if (!ENABLE_FEATURE_SEAMLESS_BZ2
+                 || magic[0] != 'B' || magic[1] != 'Z'
+                ) {
+                        bb_error_msg_and_die("no gzip"
+                                USE_FEATURE_SEAMLESS_BZ2("/bzip2")
+                                " magic");
+                }
 #if BB_MMU
-                        xformer = unpack_bz2_stream;
+                xformer = unpack_bz2_stream;
 #else
-                        xformer_prog = "bunzip2";
+                xformer_prog = "bunzip2";
 #endif
-        /* We can do better, need modifying unpack_bz2_stream to not require
-         * first 2 bytes. Not very hard to do... I mean, TODO :) */
-                        xlseek(archive_handle->src_fd, -2, SEEK_CUR);
-                } else
-                        bb_error_msg_and_die("no gzip"
-                                USE_FEATURE_RPM_BZ2("/bzip")
-                                " magic");
         } else {
 #if !BB_MMU
                 /* NOMMU version of open_transformer execs an external unzipper that should
diff --git a/archival/tar.c b/archival/tar.c
index b2481b843..45701c985 100644
--- a/archival/tar.c
+++ b/archival/tar.c
@@ -36,7 +36,7 @@
 #define block_buf bb_common_bufsiz1
 
 
-#if !ENABLE_FEATURE_TAR_GZIP && !ENABLE_FEATURE_TAR_BZIP2
+#if !ENABLE_FEATURE_SEAMLESS_GZ && !ENABLE_FEATURE_SEAMLESS_BZ2
 /* Do not pass gzip flag to writeTarFile() */
 #define writeTarFile(tar_fd, verboseFlag, dereferenceFlag, include, exclude, gzip) \
         writeTarFile(tar_fd, verboseFlag, dereferenceFlag, include, exclude)
@@ -503,19 +503,19 @@ static int FAST_FUNC writeFileToTarball(const char *fileName, struct stat *statb
         return TRUE;
 }
 
-#if ENABLE_FEATURE_TAR_GZIP || ENABLE_FEATURE_TAR_BZIP2
-#if !(ENABLE_FEATURE_TAR_GZIP && ENABLE_FEATURE_TAR_BZIP2)
+#if ENABLE_FEATURE_SEAMLESS_GZ || ENABLE_FEATURE_SEAMLESS_BZ2
+#if !(ENABLE_FEATURE_SEAMLESS_GZ && ENABLE_FEATURE_SEAMLESS_BZ2)
 #define vfork_compressor(tar_fd, gzip) vfork_compressor(tar_fd)
 #endif
 /* Don't inline: vfork scares gcc and pessimizes code */
 static void NOINLINE vfork_compressor(int tar_fd, int gzip)
 {
         pid_t gzipPid;
-#if ENABLE_FEATURE_TAR_GZIP && ENABLE_FEATURE_TAR_BZIP2
+#if ENABLE_FEATURE_SEAMLESS_GZ && ENABLE_FEATURE_SEAMLESS_BZ2
         const char *zip_exec = (gzip == 1) ? "gzip" : "bzip2";
-#elif ENABLE_FEATURE_TAR_GZIP
+#elif ENABLE_FEATURE_SEAMLESS_GZ
         const char *zip_exec = "gzip";
-#else /* only ENABLE_FEATURE_TAR_BZIP2 */
+#else /* only ENABLE_FEATURE_SEAMLESS_BZ2 */
         const char *zip_exec = "bzip2";
 #endif
         // On Linux, vfork never unpauses parent early, although standard
@@ -579,7 +579,7 @@ static void NOINLINE vfork_compressor(int tar_fd, int gzip)
                 bb_perror_msg_and_die("cannot exec %s", zip_exec);
         }
 }
-#endif /* ENABLE_FEATURE_TAR_GZIP || ENABLE_FEATURE_TAR_BZIP2 */
+#endif /* ENABLE_FEATURE_SEAMLESS_GZ || ENABLE_FEATURE_SEAMLESS_BZ2 */
 
 
 /* gcc 4.2.1 inlines it, making code bigger */
@@ -601,7 +601,7 @@ static NOINLINE int writeTarFile(int tar_fd, int verboseFlag,
         if (fstat(tbInfo.tarFd, &tbInfo.statBuf) < 0)
                 bb_perror_msg_and_die("cannot stat tar file");
 
-#if ENABLE_FEATURE_TAR_GZIP || ENABLE_FEATURE_TAR_BZIP2
+#if ENABLE_FEATURE_SEAMLESS_GZ || ENABLE_FEATURE_SEAMLESS_BZ2
         if (gzip)
                 vfork_compressor(tbInfo.tarFd, gzip);
 #endif
@@ -637,7 +637,7 @@ static NOINLINE int writeTarFile(int tar_fd, int verboseFlag,
         if (errorFlag)
                 bb_error_msg("error exit delayed from previous errors");
 
-#if ENABLE_FEATURE_TAR_GZIP || ENABLE_FEATURE_TAR_BZIP2
+#if ENABLE_FEATURE_SEAMLESS_GZ || ENABLE_FEATURE_SEAMLESS_BZ2
         if (gzip) {
                 int status;
                 if (safe_waitpid(-1, &status, 0) == -1)
@@ -679,7 +679,7 @@ static llist_t *append_file_list_to_list(llist_t *list)
 #define append_file_list_to_list(x) 0
 #endif
 
-#if ENABLE_FEATURE_TAR_COMPRESS
+#if ENABLE_FEATURE_SEAMLESS_Z
 static char FAST_FUNC get_header_tar_Z(archive_handle_t *archive_handle)
 {
         /* Can't lseek over pipes */
@@ -692,7 +692,7 @@ static char FAST_FUNC get_header_tar_Z(archive_handle_t *archive_handle)
                 bb_error_msg_and_die("invalid magic");
         }
 
-        open_transformer(archive_handle->src_fd, uncompress, "uncompress");
+        open_transformer(archive_handle->src_fd, unpack_Z_stream, "uncompress");
         archive_handle->offset = 0;
         while (get_header_tar(archive_handle) == EXIT_SUCCESS)
                 continue;
@@ -729,14 +729,14 @@ static void handle_SIGCHLD(int status)
 
 enum {
         OPTBIT_KEEP_OLD = 7,
-        USE_FEATURE_TAR_CREATE(  OPTBIT_CREATE      ,)
-        USE_FEATURE_TAR_CREATE(  OPTBIT_DEREFERENCE ,)
-        USE_FEATURE_TAR_BZIP2(   OPTBIT_BZIP2       ,)
-        USE_FEATURE_TAR_LZMA(    OPTBIT_LZMA        ,)
-        USE_FEATURE_TAR_FROM(    OPTBIT_INCLUDE_FROM,)
-        USE_FEATURE_TAR_FROM(    OPTBIT_EXCLUDE_FROM,)
-        USE_FEATURE_TAR_GZIP(    OPTBIT_GZIP        ,)
-        USE_FEATURE_TAR_COMPRESS(OPTBIT_COMPRESS    ,)
+        USE_FEATURE_TAR_CREATE(   OPTBIT_CREATE      ,)
+        USE_FEATURE_TAR_CREATE(   OPTBIT_DEREFERENCE ,)
+        USE_FEATURE_SEAMLESS_BZ2( OPTBIT_BZIP2       ,)
+        USE_FEATURE_SEAMLESS_LZMA(OPTBIT_LZMA        ,)
+        USE_FEATURE_TAR_FROM(     OPTBIT_INCLUDE_FROM,)
+        USE_FEATURE_TAR_FROM(     OPTBIT_EXCLUDE_FROM,)
+        USE_FEATURE_SEAMLESS_GZ(  OPTBIT_GZIP        ,)
+        USE_FEATURE_SEAMLESS_Z(   OPTBIT_COMPRESS    ,)
         OPTBIT_NOPRESERVE_OWN,
         OPTBIT_NOPRESERVE_PERM,
         OPT_TEST         = 1 << 0, // t
@@ -747,14 +747,14 @@ enum {
         OPT_P            = 1 << 5, // p
         OPT_VERBOSE      = 1 << 6, // v
         OPT_KEEP_OLD     = 1 << 7, // k
-        OPT_CREATE       = USE_FEATURE_TAR_CREATE(  (1<<OPTBIT_CREATE      )) + 0, // c
-        OPT_DEREFERENCE  = USE_FEATURE_TAR_CREATE(  (1<<OPTBIT_DEREFERENCE )) + 0, // h
-        OPT_BZIP2        = USE_FEATURE_TAR_BZIP2(   (1<<OPTBIT_BZIP2       )) + 0, // j
-        OPT_LZMA         = USE_FEATURE_TAR_LZMA(    (1<<OPTBIT_LZMA        )) + 0, // a
-        OPT_INCLUDE_FROM = USE_FEATURE_TAR_FROM(    (1<<OPTBIT_INCLUDE_FROM)) + 0, // T
-        OPT_EXCLUDE_FROM = USE_FEATURE_TAR_FROM(    (1<<OPTBIT_EXCLUDE_FROM)) + 0, // X
-        OPT_GZIP         = USE_FEATURE_TAR_GZIP(    (1<<OPTBIT_GZIP        )) + 0, // z
-        OPT_COMPRESS     = USE_FEATURE_TAR_COMPRESS((1<<OPTBIT_COMPRESS    )) + 0, // Z
+        OPT_CREATE       = USE_FEATURE_TAR_CREATE(   (1 << OPTBIT_CREATE      )) + 0, // c
+        OPT_DEREFERENCE  = USE_FEATURE_TAR_CREATE(   (1 << OPTBIT_DEREFERENCE )) + 0, // h
+        OPT_BZIP2        = USE_FEATURE_SEAMLESS_BZ2( (1 << OPTBIT_BZIP2       )) + 0, // j
+        OPT_LZMA         = USE_FEATURE_SEAMLESS_LZMA((1 << OPTBIT_LZMA        )) + 0, // a
+        OPT_INCLUDE_FROM = USE_FEATURE_TAR_FROM(     (1 << OPTBIT_INCLUDE_FROM)) + 0, // T
+        OPT_EXCLUDE_FROM = USE_FEATURE_TAR_FROM(     (1 << OPTBIT_EXCLUDE_FROM)) + 0, // X
+        OPT_GZIP         = USE_FEATURE_SEAMLESS_GZ(  (1 << OPTBIT_GZIP        )) + 0, // z
+        OPT_COMPRESS     = USE_FEATURE_SEAMLESS_Z(   (1 << OPTBIT_COMPRESS    )) + 0, // Z
         OPT_NOPRESERVE_OWN  = 1 << OPTBIT_NOPRESERVE_OWN , // no-same-owner
         OPT_NOPRESERVE_PERM = 1 << OPTBIT_NOPRESERVE_PERM, // no-same-permissions
 };
@@ -772,20 +772,20 @@ static const char tar_longopts[] ALIGN1 =
         "create\0"              No_argument       "c"
         "dereference\0"         No_argument       "h"
 # endif
-# if ENABLE_FEATURE_TAR_BZIP2
+# if ENABLE_FEATURE_SEAMLESS_BZ2
         "bzip2\0"               No_argument       "j"
 # endif
-# if ENABLE_FEATURE_TAR_LZMA
+# if ENABLE_FEATURE_SEAMLESS_LZMA
         "lzma\0"                No_argument       "a"
 # endif
 # if ENABLE_FEATURE_TAR_FROM
         "files-from\0"          Required_argument "T"
         "exclude-from\0"        Required_argument "X"
 # endif
-# if ENABLE_FEATURE_TAR_GZIP
+# if ENABLE_FEATURE_SEAMLESS_GZ
         "gzip\0"                No_argument       "z"
 # endif
-# if ENABLE_FEATURE_TAR_COMPRESS
+# if ENABLE_FEATURE_SEAMLESS_Z
         "compress\0"            No_argument       "Z"
 # endif
         "no-same-owner\0"       No_argument       "\xfd"
@@ -834,12 +834,12 @@ int tar_main(int argc UNUSED_PARAM, char **argv)
 #endif
         opt = getopt32(argv,
                 "txC:f:Opvk"
-                USE_FEATURE_TAR_CREATE(  "ch"  )
-                USE_FEATURE_TAR_BZIP2(   "j"   )
-                USE_FEATURE_TAR_LZMA(    "a"   )
-                USE_FEATURE_TAR_FROM(    "T:X:")
-                USE_FEATURE_TAR_GZIP(    "z"   )
-                USE_FEATURE_TAR_COMPRESS("Z"   )
+                USE_FEATURE_TAR_CREATE(   "ch"  )
+                USE_FEATURE_SEAMLESS_BZ2( "j"   )
+                USE_FEATURE_SEAMLESS_LZMA("a"   )
+                USE_FEATURE_TAR_FROM(     "T:X:")
+                USE_FEATURE_SEAMLESS_GZ(  "z"   )
+                USE_FEATURE_SEAMLESS_Z(   "Z"   )
                 , &base_dir // -C dir
                 , &tar_filename // -f filename
                 USE_FEATURE_TAR_FROM(, &(tar_handle->accept)) // T
@@ -922,8 +922,7 @@ int tar_main(int argc UNUSED_PARAM, char **argv)
 
                         tar_stream = stdout;
                         /* Mimicking GNU tar 1.15.1: */
-                        flags = O_WRONLY|O_CREAT|O_TRUNC;
-                /* was doing unlink; open(O_WRONLY|O_CREAT|O_EXCL); why? */
+                        flags = O_WRONLY | O_CREAT | O_TRUNC;
                 } else {
                         tar_stream = stdin;
                         flags = O_RDONLY;
@@ -933,7 +932,14 @@ int tar_main(int argc UNUSED_PARAM, char **argv)
                         tar_handle->src_fd = fileno(tar_stream);
                         tar_handle->seek = seek_by_read;
                 } else {
-                        tar_handle->src_fd = xopen(tar_filename, flags);
+                        if (ENABLE_FEATURE_TAR_AUTODETECT && flags == O_RDONLY) {
+                                get_header_ptr = get_header_tar;
+                                tar_handle->src_fd = open_zipped(tar_filename);
+                                if (tar_handle->src_fd < 0)
+                                        bb_perror_msg_and_die("can't open '%s'", tar_filename);
+                        } else {
+                                tar_handle->src_fd = xopen(tar_filename, flags);
+                        }
                 }
         }
 
@@ -947,11 +953,11 @@ int tar_main(int argc UNUSED_PARAM, char **argv)
 
         /* create an archive */
         if (opt & OPT_CREATE) {
-#if ENABLE_FEATURE_TAR_GZIP || ENABLE_FEATURE_TAR_BZIP2
+#if ENABLE_FEATURE_SEAMLESS_GZ || ENABLE_FEATURE_SEAMLESS_BZ2
                 int zipMode = 0;
-                if (ENABLE_FEATURE_TAR_GZIP && (opt & OPT_GZIP))
+                if (ENABLE_FEATURE_SEAMLESS_GZ && (opt & OPT_GZIP))
                         zipMode = 1;
-                if (ENABLE_FEATURE_TAR_BZIP2 && (opt & OPT_BZIP2))
+                if (ENABLE_FEATURE_SEAMLESS_BZ2 && (opt & OPT_BZIP2))
                         zipMode = 2;
 #endif
                 /* NB: writeTarFile() closes tar_handle->src_fd */