[PATCH] libarchive: add a function to unpack embedded data
Ron Yorston
rmy at pobox.com
Fri Nov 2 08:34:16 UTC 2018
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 at pobox.com>
---
archival/libarchive/decompress_bunzip2.c | 38 +++++++++--
include/bb_archive.h | 7 +-
libbb/appletlib.c | 81 +++++-------------------
miscutils/bbconfig.c | 27 ++------
4 files changed, 54 insertions(+), 99 deletions(-)
diff --git a/archival/libarchive/decompress_bunzip2.c b/archival/libarchive/decompress_bunzip2.c
index 7ef4e035f..3deb213a8 100644
--- a/archival/libarchive/decompress_bunzip2.c
+++ b/archival/libarchive/decompress_bunzip2.c
@@ -107,7 +107,7 @@ struct bunzip_data {
uint8_t selectors[32768]; /* nSelectors=15 bits */
struct group_data groups[MAX_GROUPS]; /* Huffman coding tables */
};
-/* typedef struct bunzip_data bunzip_data; -- done in .h file */
+typedef struct bunzip_data bunzip_data;
/* Return the next nnn bits of input. All reads from the compressed input
@@ -575,7 +575,7 @@ static int get_next_block(bunzip_data *bd)
in outbuf. IOW: on EOF returns len ("all bytes are not filled"), not 0.
(Why? This allows to get rid of one local variable)
*/
-int FAST_FUNC read_bunzip(bunzip_data *bd, char *outbuf, int len)
+static int FAST_FUNC read_bunzip(bunzip_data *bd, char *outbuf, int len)
{
const uint32_t *dbuf;
int pos, current, previous;
@@ -699,7 +699,7 @@ int FAST_FUNC read_bunzip(bunzip_data *bd, char *outbuf, int len)
/* Because bunzip2 is used for help text unpacking, and because bb_show_usage()
should work for NOFORK applets too, we must be extremely careful to not leak
any allocations! */
-int FAST_FUNC start_bunzip(
+static int FAST_FUNC start_bunzip(
void *jmpbuf,
bunzip_data **bdp,
int in_fd,
@@ -759,7 +759,7 @@ int FAST_FUNC start_bunzip(
return RETVAL_OK;
}
-void FAST_FUNC dealloc_bunzip(bunzip_data *bd)
+static void FAST_FUNC dealloc_bunzip(bunzip_data *bd)
{
free(bd->dbuf);
free(bd);
@@ -847,6 +847,36 @@ unpack_bz2_stream(transformer_state_t *xstate)
return i ? i : IF_DESKTOP(total_written) + 0;
}
+const char * FAST_FUNC
+unpack_bz2_data(const char *packed, int packed_len, int unpacked_len)
+{
+ char *outbuf = NULL;
+ 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: */ packed,
+ /* len: */ packed_len
+ );
+ }
+ /* 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! */
+ outbuf = malloc_or_warn(unpacked_len);
+ if (outbuf)
+ read_bunzip(bd, outbuf, unpacked_len);
+ }
+ dealloc_bunzip(bd);
+ return outbuf;
+}
+
#ifdef TESTING
static char *const bunzip_errors[] = {
diff --git a/include/bb_archive.h b/include/bb_archive.h
index d2022336b..0dbe17496 100644
--- a/include/bb_archive.h
+++ b/include/bb_archive.h
@@ -214,12 +214,7 @@ const llist_t *find_list_entry(const llist_t *list, const char *filename) FAST_F
const llist_t *find_list_entry2(const llist_t *list, const char *filename) FAST_FUNC;
/* A bit of bunzip2 internals are exposed for compressed help support: */
-typedef struct bunzip_data bunzip_data;
-int start_bunzip(void *, bunzip_data **bdp, int in_fd, const void *inbuf, int len) FAST_FUNC;
-/* NB: read_bunzip returns < 0 on error, or the number of *unfilled* bytes
- * in outbuf. IOW: on EOF returns len ("all bytes are not filled"), not 0: */
-int read_bunzip(bunzip_data *bd, char *outbuf, int len) FAST_FUNC;
-void dealloc_bunzip(bunzip_data *bd) FAST_FUNC;
+const char *unpack_bz2_data(const char *packed, int packed_len, int unpacked_len) FAST_FUNC;
/* Meaning and direction (input/output) of the fields are transformer-specific */
typedef struct transformer_state_t {
diff --git a/libbb/appletlib.c b/libbb/appletlib.c
index d48b2ea60..6dfaf1f41 100644
--- a/libbb/appletlib.c
+++ b/libbb/appletlib.c
@@ -107,34 +107,8 @@ static const char usage_messages[] ALIGN1 = UNPACKED_USAGE;
static const char packed_usage[] ALIGN1 = { PACKED_USAGE };
# include "bb_archive.h"
-static const char *unpack_usage_messages(void)
-{
- char *outbuf = NULL;
- 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: */ packed_usage,
- /* len: */ sizeof(packed_usage)
- );
- }
- /* 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! */
- outbuf = malloc_or_warn(sizeof(UNPACKED_USAGE));
- if (outbuf)
- read_bunzip(bd, outbuf, sizeof(UNPACKED_USAGE));
- }
- dealloc_bunzip(bd);
- return outbuf;
-}
+# define unpack_usage_messages() \
+ unpack_bz2_data(packed_usage, sizeof(packed_usage), sizeof(UNPACKED_USAGE))
# define dealloc_usage_messages(s) free(s)
#else
@@ -152,21 +126,23 @@ void FAST_FUNC bb_show_usage(void)
/* Imagine that this applet is "true". Dont suck in printf! */
const char *usage_string = unpack_usage_messages();
- if (*usage_string == '\b') {
- full_write2_str("No help available.\n\n");
- } else {
- full_write2_str("Usage: "SINGLE_APPLET_STR" ");
- full_write2_str(usage_string);
- full_write2_str("\n\n");
+ if (usage_string) {
+ if (*usage_string == '\b') {
+ full_write2_str("No help available.\n\n");
+ } else {
+ full_write2_str("Usage: "SINGLE_APPLET_STR" ");
+ full_write2_str(usage_string);
+ full_write2_str("\n\n");
+ }
+ if (ENABLE_FEATURE_CLEAN_UP)
+ dealloc_usage_messages((char*)usage_string);
}
- if (ENABLE_FEATURE_CLEAN_UP)
- dealloc_usage_messages((char*)usage_string);
#else
const char *p;
const char *usage_string = p = unpack_usage_messages();
int ap = find_applet_by_name(applet_name);
- if (ap < 0) /* never happens, paranoia */
+ if (ap < 0 || usage_string == NULL)
xfunc_die();
while (ap) {
while (*p++) continue;
@@ -986,38 +962,11 @@ find_script_by_name(const char *name)
return -0x10000; /* make it so that NUM_APPLETS + <error> is still < 0 */
}
-static char *
-unpack_scripts(void)
-{
- char *outbuf = NULL;
- 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: */ packed_scripts,
- /* len: */ sizeof(packed_scripts)
- );
- }
- /* read_bunzip can longjmp and end up here with i != 0
- * on read data errors! Not trivial */
- if (i == 0) {
- outbuf = xmalloc(UNPACKED_SCRIPTS_LENGTH);
- read_bunzip(bd, outbuf, UNPACKED_SCRIPTS_LENGTH);
- }
- dealloc_bunzip(bd);
- return outbuf;
-}
-
char* FAST_FUNC
get_script_content(unsigned n)
{
- char *t = unpack_scripts();
+ char *t = unpack_bz2_data(packed_scripts, sizeof(packed_scripts),
+ UNPACKED_SCRIPTS_LENGTH);
if (t) {
while (n != 0) {
while (*t++ != '\0')
diff --git a/miscutils/bbconfig.c b/miscutils/bbconfig.c
index 501349548..11698de94 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);
--
2.19.1
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