[PATCH] libarchive: add a function to unpack embedded data
Sam Liddicott
sam at liddicott.com
Fri Nov 2 15:41:25 UTC 2018
Will that support an embedded .profile there as well?
Sam
On Fri, 2 Nov 2018 at 13:19, Denys Vlasenko <vda.linux at googlemail.com>
wrote:
> Applied, thanks!
> On Fri, Nov 2, 2018 at 9:34 AM Ron Yorston <rmy at pobox.com> wrote:
> >
> > 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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