tar: change -a from meaning "lzma" to mean "autodetect by extension"

function                                             old     new   delta
tar_main                                            1026    1100     +74
packed_usage                                       33311   33329     +18
tar_longopts                                         309     325     +16
vfork_compressor                                     246     210     -36
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 3/1 up/down: 108/-36)            Total: 72 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

diff --git a/archival/tar.c b/archival/tar.c
index f10781a581d0135c0fcc469f435002917b75d780..4f64d22861991aa44c8ad9edd67ae1298f5d2d9d 100644 (file)
--- a/archival/tar.c
+++ b/archival/tar.c
@@ -637,8 +637,14 @@ static void NOINLINE vfork_compressor(int tar_fd, const char *gzip)
                }
                xmove_fd(data.rd, 0);
                xmove_fd(tfd, 1);
-               /* exec gzip/bzip2 program/applet */
-               BB_EXECLP(gzip, gzip, "-f", (char *)0);
+
+               /* exec gzip/bzip2/... program */
+               //BB_EXECLP(gzip, gzip, "-f", (char *)0); - WRONG for "xz",
+               // if xz is an enabled applet, it'll be a version which
+               // can only decompress. We do need to execute external
+               // program, not applet.
+               execlp(gzip, gzip, "-f", (char *)0);
+
                vfork_exec_errno = errno;
                _exit(EXIT_FAILURE);
        }
@@ -762,7 +768,7 @@ static llist_t *append_file_list_to_list(llist_t *list)
 //usage:       IF_FEATURE_SEAMLESS_GZ("z")
 //usage:       IF_FEATURE_SEAMLESS_XZ("J")
 //usage:       IF_FEATURE_SEAMLESS_BZ2("j")
-//usage:       IF_FEATURE_SEAMLESS_LZMA("a")
+//usage:       "a"
 //usage:       IF_FEATURE_TAR_CREATE("h")
 //usage:       IF_FEATURE_TAR_NOPRESERVE_TIME("m")
 //usage:       "vokO] "
@@ -801,9 +807,7 @@ static llist_t *append_file_list_to_list(llist_t *list)
 //usage:       IF_FEATURE_SEAMLESS_BZ2(
 //usage:     "\n       -j      (De)compress using bzip2"
 //usage:       )
-//usage:       IF_FEATURE_SEAMLESS_LZMA(
-//usage:     "\n       -a      (De)compress using lzma"
-//usage:       )
+//usage:     "\n       -a      (De)compress based on extension"
 //usage:       IF_FEATURE_TAR_CREATE(
 //usage:     "\n       -h      Follow symlinks"
 //usage:       )
@@ -820,6 +824,7 @@ static llist_t *append_file_list_to_list(llist_t *list)
 //usage:       "$ tar -cf /tmp/tarball.tar /usr/local\n"
 
 // Supported but aren't in --help:
+//     lzma
 //     no-recursion
 //     numeric-owner
 //     no-same-permissions
@@ -833,15 +838,16 @@ enum {
        IF_FEATURE_TAR_CREATE(   OPTBIT_CREATE      ,)
        IF_FEATURE_TAR_CREATE(   OPTBIT_DEREFERENCE ,)
        IF_FEATURE_SEAMLESS_BZ2( OPTBIT_BZIP2       ,)
-       IF_FEATURE_SEAMLESS_LZMA(OPTBIT_LZMA        ,)
        IF_FEATURE_TAR_FROM(     OPTBIT_INCLUDE_FROM,)
        IF_FEATURE_TAR_FROM(     OPTBIT_EXCLUDE_FROM,)
        IF_FEATURE_SEAMLESS_GZ(  OPTBIT_GZIP        ,)
-       IF_FEATURE_SEAMLESS_XZ(  OPTBIT_XZ          ,) // 16th bit
-       IF_FEATURE_SEAMLESS_Z(   OPTBIT_COMPRESS    ,)
+       IF_FEATURE_SEAMLESS_XZ(  OPTBIT_XZ          ,)
+       IF_FEATURE_SEAMLESS_Z(   OPTBIT_COMPRESS    ,) // 16th bit
+       OPTBIT_AUTOCOMPRESS_BY_EXT,
        IF_FEATURE_TAR_NOPRESERVE_TIME(OPTBIT_NOPRESERVE_TIME,)
 #if ENABLE_FEATURE_TAR_LONG_OPTIONS
        OPTBIT_STRIP_COMPONENTS,
+       IF_FEATURE_SEAMLESS_LZMA(OPTBIT_LZMA        ,)
        OPTBIT_NORECURSION,
        IF_FEATURE_TAR_TO_COMMAND(OPTBIT_2COMMAND   ,)
        OPTBIT_NUMERIC_OWNER,
@@ -860,14 +866,15 @@ enum {
        OPT_CREATE       = IF_FEATURE_TAR_CREATE(   (1 << OPTBIT_CREATE      )) + 0, // c
        OPT_DEREFERENCE  = IF_FEATURE_TAR_CREATE(   (1 << OPTBIT_DEREFERENCE )) + 0, // h
        OPT_BZIP2        = IF_FEATURE_SEAMLESS_BZ2( (1 << OPTBIT_BZIP2       )) + 0, // j
-       OPT_LZMA         = IF_FEATURE_SEAMLESS_LZMA((1 << OPTBIT_LZMA        )) + 0, // a
        OPT_INCLUDE_FROM = IF_FEATURE_TAR_FROM(     (1 << OPTBIT_INCLUDE_FROM)) + 0, // T
        OPT_EXCLUDE_FROM = IF_FEATURE_TAR_FROM(     (1 << OPTBIT_EXCLUDE_FROM)) + 0, // X
        OPT_GZIP         = IF_FEATURE_SEAMLESS_GZ(  (1 << OPTBIT_GZIP        )) + 0, // z
        OPT_XZ           = IF_FEATURE_SEAMLESS_XZ(  (1 << OPTBIT_XZ          )) + 0, // J
        OPT_COMPRESS     = IF_FEATURE_SEAMLESS_Z(   (1 << OPTBIT_COMPRESS    )) + 0, // Z
+       OPT_AUTOCOMPRESS_BY_EXT = 1 << OPTBIT_AUTOCOMPRESS_BY_EXT,                   // a
        OPT_NOPRESERVE_TIME  = IF_FEATURE_TAR_NOPRESERVE_TIME((1 << OPTBIT_NOPRESERVE_TIME)) + 0, // m
        OPT_STRIP_COMPONENTS = IF_FEATURE_TAR_LONG_OPTIONS((1 << OPTBIT_STRIP_COMPONENTS)) + 0, // strip-components
+       OPT_LZMA             = IF_FEATURE_TAR_LONG_OPTIONS(IF_FEATURE_SEAMLESS_LZMA((1 << OPTBIT_LZMA))) + 0, // lzma
        OPT_NORECURSION      = IF_FEATURE_TAR_LONG_OPTIONS((1 << OPTBIT_NORECURSION    )) + 0, // no-recursion
        OPT_2COMMAND         = IF_FEATURE_TAR_TO_COMMAND(  (1 << OPTBIT_2COMMAND       )) + 0, // to-command
        OPT_NUMERIC_OWNER    = IF_FEATURE_TAR_LONG_OPTIONS((1 << OPTBIT_NUMERIC_OWNER  )) + 0, // numeric-owner
@@ -897,9 +904,6 @@ static const char tar_longopts[] ALIGN1 =
 # if ENABLE_FEATURE_SEAMLESS_BZ2
        "bzip2\0"               No_argument       "j"
 # endif
-# 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"
@@ -913,10 +917,14 @@ static const char tar_longopts[] ALIGN1 =
 # if ENABLE_FEATURE_SEAMLESS_Z
        "compress\0"            No_argument       "Z"
 # endif
+       "auto-compress\0"       No_argument       "a"
 # if ENABLE_FEATURE_TAR_NOPRESERVE_TIME
        "touch\0"               No_argument       "m"
 # endif
-       "strip-components\0"    Required_argument "\xf9"
+       "strip-components\0"    Required_argument "\xf8"
+# if ENABLE_FEATURE_SEAMLESS_LZMA
+       "lzma\0"                No_argument       "\xf9"
+# endif
        "no-recursion\0"        No_argument       "\xfa"
 # if ENABLE_FEATURE_TAR_TO_COMMAND
        "to-command\0"          Required_argument "\xfb"
@@ -1005,13 +1013,13 @@ int tar_main(int argc UNUSED_PARAM, char **argv)
                "txC:f:Oopvk"
                IF_FEATURE_TAR_CREATE(   "ch"    )
                IF_FEATURE_SEAMLESS_BZ2( "j"     )
-               IF_FEATURE_SEAMLESS_LZMA("a"     )
                IF_FEATURE_TAR_FROM(     "T:*X:*")
                IF_FEATURE_SEAMLESS_GZ(  "z"     )
                IF_FEATURE_SEAMLESS_XZ(  "J"     )
                IF_FEATURE_SEAMLESS_Z(   "Z"     )
+               "a"
                IF_FEATURE_TAR_NOPRESERVE_TIME("m")
-               IF_FEATURE_TAR_LONG_OPTIONS("\xf9:") // --strip-components
+               IF_FEATURE_TAR_LONG_OPTIONS("\xf8:") // --strip-components
                "\0"
                "tt:vv:" // count -t,-v
 #if ENABLE_FEATURE_TAR_LONG_OPTIONS && ENABLE_FEATURE_TAR_FROM
@@ -1040,7 +1048,7 @@ int tar_main(int argc UNUSED_PARAM, char **argv)
                );
 #if DBG_OPTION_PARSING
        bb_error_msg("opt: 0x%08x", opt);
-# define showopt(o) bb_error_msg("opt & %s(%x): %x", #o, o, opt & o);
+# define showopt(o) bb_error_msg("opt & %s(%x):\t%x", #o, o, opt & o);
        showopt(OPT_TEST            );
        showopt(OPT_EXTRACT         );
        showopt(OPT_BASEDIR         );
@@ -1053,14 +1061,15 @@ int tar_main(int argc UNUSED_PARAM, char **argv)
        showopt(OPT_CREATE          );
        showopt(OPT_DEREFERENCE     );
        showopt(OPT_BZIP2           );
-       showopt(OPT_LZMA            );
        showopt(OPT_INCLUDE_FROM    );
        showopt(OPT_EXCLUDE_FROM    );
        showopt(OPT_GZIP            );
        showopt(OPT_XZ              );
        showopt(OPT_COMPRESS        );
+       showopt(OPT_AUTOCOMPRESS_BY_EXT);
        showopt(OPT_NOPRESERVE_TIME );
        showopt(OPT_STRIP_COMPONENTS);
+       showopt(OPT_LZMA            );
        showopt(OPT_NORECURSION     );
        showopt(OPT_2COMMAND        );
        showopt(OPT_NUMERIC_OWNER   );
@@ -1179,6 +1188,21 @@ int tar_main(int argc UNUSED_PARAM, char **argv)
                                bb_perror_msg_and_die("can't open '%s'", tar_filename);
                } else {
                        tar_handle->src_fd = xopen(tar_filename, flags);
+#if ENABLE_FEATURE_TAR_CREATE
+                       if ((OPT_GZIP | OPT_BZIP2 | OPT_XZ | OPT_LZMA) != 0 /* at least one is config-enabled */
+                        && (opt & OPT_AUTOCOMPRESS_BY_EXT)
+                        && flags != O_RDONLY
+                       ) {
+                               if (OPT_GZIP != 0 && is_suffixed_with(tar_filename, "gz"))
+                                       opt |= OPT_GZIP;
+                               if (OPT_BZIP2 != 0 && is_suffixed_with(tar_filename, "bz2"))
+                                       opt |= OPT_BZIP2;
+                               if (OPT_XZ != 0 && is_suffixed_with(tar_filename, "xz"))
+                                       opt |= OPT_XZ;
+                               if (OPT_LZMA != 0 && is_suffixed_with(tar_filename, "lzma"))
+                                       opt |= OPT_LZMA;
+                       }
+#endif
                }
        }