libarchive: add a function to unpack embedded data

Similar code to unpack embedded data is used to decompress usage
messages, embedded scripts and the config file (in the non-default
bbconfig applet).

Moving this code to a common function reduces the size of the default
build and hides more of the internals of libarchive.

function                                             old     new   delta
unpack_bz2_data                                        -     135    +135
bb_show_usage                                        137     157     +20
get_script_content                                    32      47     +15
unpack_scripts                                       119       -    -119
unpack_usage_messages                                124       -    -124
------------------------------------------------------------------------------
(add/remove: 1/2 grow/shrink: 2/0 up/down: 170/-243)          Total: -73 bytes

Signed-off-by: Ron Yorston <rmy@pobox.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 4 insertions, 23 deletions

diff --git a/miscutils/bbconfig.c b/miscutils/bbconfig.c
index 501349548..fe02516a8 100644
--- a/miscutils/bbconfig.c
+++ b/miscutils/bbconfig.c
@@ -43,29 +43,10 @@ int bbconfig_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 int bbconfig_main(int argc UNUSED_PARAM, char **argv UNUSED_PARAM)
 {
 #if ENABLE_FEATURE_COMPRESS_BBCONFIG
-        bunzip_data *bd;
-        int i;
-        jmp_buf jmpbuf;
-
-        /* Setup for I/O error handling via longjmp */
-        i = setjmp(jmpbuf);
-        if (i == 0) {
-                i = start_bunzip(&jmpbuf,
-                        &bd,
-                        /* src_fd: */ -1,
-                        /* inbuf:  */ bbconfig_config_bz2,
-                        /* len:    */ sizeof(bbconfig_config_bz2)
-                );
-        }
-        /* read_bunzip can longjmp and end up here with i != 0
-         * on read data errors! Not trivial */
-        if (i == 0) {
-                /* Cannot use xmalloc: will leak bd in NOFORK case! */
-                char *outbuf = malloc_or_warn(sizeof(bbconfig_config));
-                if (outbuf) {
-                        read_bunzip(bd, outbuf, sizeof(bbconfig_config));
-                        full_write1_str(outbuf);
-                }
+        const char *outbuf = unpack_bz2_data(bbconfig_config_bz2,
+                        sizeof(bbconfig_config_bz2), sizeof(bbconfig_config));
+        if (outbuf) {
+                full_write1_str(outbuf);
         }
 #else
         full_write1_str(bbconfig_config);