svn commit: trunk/busybox: archival docs
vda at busybox.net
vda at busybox.net
Wed Mar 14 00:07:52 UTC 2007
Author: vda
Date: 2007-03-13 17:07:51 -0700 (Tue, 13 Mar 2007)
New Revision: 18093
Log:
gzip: use common bbunzip infrastructure - ~700 bytes code less
Added:
trunk/busybox/docs/keep_data_small.txt
Modified:
trunk/busybox/archival/Kbuild
trunk/busybox/archival/bbunzip.c
trunk/busybox/archival/gzip.c
Changeset:
Modified: trunk/busybox/archival/Kbuild
===================================================================
--- trunk/busybox/archival/Kbuild 2007-03-14 00:06:51 UTC (rev 18092)
+++ trunk/busybox/archival/Kbuild 2007-03-14 00:07:51 UTC (rev 18093)
@@ -14,7 +14,7 @@
lib-$(CONFIG_DPKG) += dpkg.o
lib-$(CONFIG_DPKG_DEB) += dpkg_deb.o
lib-$(CONFIG_GUNZIP) += bbunzip.o
-lib-$(CONFIG_GZIP) += gzip.o
+lib-$(CONFIG_GZIP) += gzip.o bbunzip.o
lib-$(CONFIG_RPM2CPIO) += rpm2cpio.o
lib-$(CONFIG_RPM) += rpm.o
lib-$(CONFIG_TAR) += tar.o
Modified: trunk/busybox/archival/bbunzip.c
===================================================================
--- trunk/busybox/archival/bbunzip.c 2007-03-14 00:06:51 UTC (rev 18092)
+++ trunk/busybox/archival/bbunzip.c 2007-03-14 00:07:51 UTC (rev 18093)
@@ -9,12 +9,12 @@
#include "unarchive.h"
enum {
- OPT_STDOUT = 1,
- OPT_FORCE = 2,
+ OPT_STDOUT = 0x1,
+ OPT_FORCE = 0x2,
/* gunzip only: */
- OPT_TEST = 4,
- OPT_DECOMPRESS = 8,
- OPT_VERBOSE = 0x10,
+ OPT_VERBOSE = 0x4,
+ OPT_DECOMPRESS = 0x8,
+ OPT_TEST = 0x10,
};
static
@@ -33,8 +33,7 @@
return 0;
}
-static
-int unpack(char **argv,
+int bbunpack(char **argv,
char* (*make_new_name)(char *filename),
USE_DESKTOP(long long) int (*unpacker)(void)
)
@@ -173,7 +172,7 @@
if (applet_name[2] == 'c')
option_mask32 |= OPT_STDOUT;
- return unpack(argv, make_new_name_bunzip2, unpack_bunzip2);
+ return bbunpack(argv, make_new_name_bunzip2, unpack_bunzip2);
}
#endif
@@ -267,13 +266,13 @@
int gunzip_main(int argc, char **argv);
int gunzip_main(int argc, char **argv)
{
- getopt32(argc, argv, "cftdv");
+ getopt32(argc, argv, "cfvdt");
argv += optind;
/* if called as zcat */
if (applet_name[1] == 'c')
option_mask32 |= OPT_STDOUT;
- return unpack(argv, make_new_name_gunzip, unpack_gunzip);
+ return bbunpack(argv, make_new_name_gunzip, unpack_gunzip);
}
#endif
@@ -311,7 +310,7 @@
if (applet_name[4] == 'c')
option_mask32 |= OPT_STDOUT;
- return unpack(argv, make_new_name_unlzma, unpack_unlzma);
+ return bbunpack(argv, make_new_name_unlzma, unpack_unlzma);
}
#endif
@@ -350,7 +349,7 @@
getopt32(argc, argv, "cf");
argv += optind;
- return unpack(argv, make_new_name_uncompress, unpack_uncompress);
+ return bbunpack(argv, make_new_name_uncompress, unpack_uncompress);
}
#endif
Modified: trunk/busybox/archival/gzip.c
===================================================================
--- trunk/busybox/archival/gzip.c 2007-03-14 00:06:51 UTC (rev 18092)
+++ trunk/busybox/archival/gzip.c 2007-03-14 00:07:51 UTC (rev 18093)
@@ -2074,6 +2074,7 @@
/* ======================================================================== */
+#if 0
static void abort_gzip(int ATTRIBUTE_UNUSED ignored)
{
exit(1);
@@ -2082,93 +2083,7 @@
int gzip_main(int argc, char **argv);
int gzip_main(int argc, char **argv)
{
- enum {
- OPT_tostdout = 0x1,
- OPT_force = 0x2,
- };
- unsigned opt;
- int inFileNum;
- int outFileNum;
- int i;
- struct stat statBuf;
-
- opt = getopt32(argc, argv, "cf123456789qv" USE_GUNZIP("d"));
- //if (opt & 0x1) // -c
- //if (opt & 0x2) // -f
- /* Ignore 1-9 (compression level) options */
- //if (opt & 0x4) // -1
- //if (opt & 0x8) // -2
- //if (opt & 0x10) // -3
- //if (opt & 0x20) // -4
- //if (opt & 0x40) // -5
- //if (opt & 0x80) // -6
- //if (opt & 0x100) // -7
- //if (opt & 0x200) // -8
- //if (opt & 0x400) // -9
- //if (opt & 0x800) // -q
- //if (opt & 0x1000) // -v
-#if ENABLE_GUNZIP /* gunzip_main may not be visible... */
- if (opt & 0x2000) { // -d
- /* FIXME: getopt32 should not depend on optind */
- optind = 1;
- return gunzip_main(argc, argv);
- }
-#endif
-
- /* Comment?? */
- if (signal(SIGINT, SIG_IGN) != SIG_IGN) {
- signal(SIGINT, abort_gzip);
- }
-#ifdef SIGTERM
- if (signal(SIGTERM, SIG_IGN) != SIG_IGN) {
- signal(SIGTERM, abort_gzip);
- }
-#endif
-#ifdef SIGHUP
- if (signal(SIGHUP, SIG_IGN) != SIG_IGN) {
- signal(SIGHUP, abort_gzip);
- }
-#endif
-
- ptr_to_globals = xzalloc(sizeof(struct global1) + sizeof(struct global2));
- ptr_to_globals++;
- G2.l_desc.dyn_tree = G2.dyn_ltree;
- G2.l_desc.static_tree = G2.static_ltree;
- G2.l_desc.extra_bits = extra_lbits;
- G2.l_desc.extra_base = LITERALS + 1;
- G2.l_desc.elems = L_CODES;
- G2.l_desc.max_length = MAX_BITS;
- //G2.l_desc.max_code = 0;
-
- G2.d_desc.dyn_tree = G2.dyn_dtree;
- G2.d_desc.static_tree = G2.static_dtree;
- G2.d_desc.extra_bits = extra_dbits;
- //G2.d_desc.extra_base = 0;
- G2.d_desc.elems = D_CODES;
- G2.d_desc.max_length = MAX_BITS;
- //G2.d_desc.max_code = 0;
-
- G2.bl_desc.dyn_tree = G2.bl_tree;
- //G2.bl_desc.static_tree = NULL;
- G2.bl_desc.extra_bits = extra_blbits,
- //G2.bl_desc.extra_base = 0;
- G2.bl_desc.elems = BL_CODES;
- G2.bl_desc.max_length = MAX_BL_BITS;
- //G2.bl_desc.max_code = 0;
-
- /* Allocate all global buffers (for DYN_ALLOC option) */
- ALLOC(uch, G1.l_buf, INBUFSIZ);
- ALLOC(uch, G1.outbuf, OUTBUFSIZ);
- ALLOC(ush, G1.d_buf, DIST_BUFSIZE);
- ALLOC(uch, G1.window, 2L * WSIZE);
- ALLOC(ush, G1.prev, 1L << BITS);
-
- /* Initialise the CRC32 table */
- G1.crc_32_tab = crc32_filltable(0);
-
- clear_bufs();
-
if (optind == argc) {
G1.time_stamp = 0;
zip(STDIN_FILENO, STDOUT_FILENO);
@@ -2240,3 +2155,87 @@
return 0; //##G1.exit_code;
}
+#endif
+
+int bbunpack(char **argv,
+ char* (*make_new_name)(char *filename),
+ USE_DESKTOP(long long) int (*unpacker)(void)
+);
+
+static
+char* make_new_name_gzip(char *filename)
+{
+ return xasprintf("%s.gz", filename);
+}
+
+static
+USE_DESKTOP(long long) int pack_gzip(void)
+{
+ struct stat s;
+
+ G1.time_stamp = 0;
+ if (!fstat(STDIN_FILENO, &s))
+ G1.time_stamp = s.st_ctime;
+ zip(STDIN_FILENO, STDOUT_FILENO);
+ return 0;
+}
+
+int gzip_main(int argc, char **argv);
+int gzip_main(int argc, char **argv)
+{
+ unsigned opt;
+
+ /* Must match bbunzip's constants OPT_STDOUT, OPT_FORCE! */
+ opt = getopt32(argc, argv, "cfv" USE_GUNZIP("d") "q123456789" );
+ option_mask32 &= 0x7; /* Clear -d, ignore -q, -0..9 */
+ //if (opt & 0x1) // -c
+ //if (opt & 0x2) // -f
+ //if (opt & 0x4) // -v
+#if ENABLE_GUNZIP /* gunzip_main may not be visible... */
+ if (opt & 0x8) { // -d
+ /* FIXME: getopt32 should not depend on optind */
+ optind = 1;
+ return gunzip_main(argc, argv);
+ }
+#endif
+
+ ptr_to_globals = xzalloc(sizeof(struct global1) + sizeof(struct global2));
+ ptr_to_globals++;
+ G2.l_desc.dyn_tree = G2.dyn_ltree;
+ G2.l_desc.static_tree = G2.static_ltree;
+ G2.l_desc.extra_bits = extra_lbits;
+ G2.l_desc.extra_base = LITERALS + 1;
+ G2.l_desc.elems = L_CODES;
+ G2.l_desc.max_length = MAX_BITS;
+ //G2.l_desc.max_code = 0;
+
+ G2.d_desc.dyn_tree = G2.dyn_dtree;
+ G2.d_desc.static_tree = G2.static_dtree;
+ G2.d_desc.extra_bits = extra_dbits;
+ //G2.d_desc.extra_base = 0;
+ G2.d_desc.elems = D_CODES;
+ G2.d_desc.max_length = MAX_BITS;
+ //G2.d_desc.max_code = 0;
+
+ G2.bl_desc.dyn_tree = G2.bl_tree;
+ //G2.bl_desc.static_tree = NULL;
+ G2.bl_desc.extra_bits = extra_blbits,
+ //G2.bl_desc.extra_base = 0;
+ G2.bl_desc.elems = BL_CODES;
+ G2.bl_desc.max_length = MAX_BL_BITS;
+ //G2.bl_desc.max_code = 0;
+
+ /* Allocate all global buffers (for DYN_ALLOC option) */
+ ALLOC(uch, G1.l_buf, INBUFSIZ);
+ ALLOC(uch, G1.outbuf, OUTBUFSIZ);
+ ALLOC(ush, G1.d_buf, DIST_BUFSIZE);
+ ALLOC(uch, G1.window, 2L * WSIZE);
+ ALLOC(ush, G1.prev, 1L << BITS);
+
+ /* Initialise the CRC32 table */
+ G1.crc_32_tab = crc32_filltable(0);
+
+ clear_bufs();
+
+ return bbunpack(argv, make_new_name_gzip, pack_gzip);
+}
Added: trunk/busybox/docs/keep_data_small.txt
===================================================================
--- trunk/busybox/docs/keep_data_small.txt (rev 0)
+++ trunk/busybox/docs/keep_data_small.txt 2007-03-14 00:07:51 UTC (rev 18093)
@@ -0,0 +1,88 @@
+ Keeping data small
+
+When many applets are compiled into busybox, all rw data and
+bss for each applet are concatenated. Including those from libc,
+if static bbox is built. When bbox is started, _all_ this data
+is allocated, not just that one part for selected applet.
+
+What "allocated" exactly means, depends on arch.
+On nommu it's probably bites the most, actually using real
+RAM for rwdata and bss. On i386, bss is lazily allocated
+by COWed zero pages. Not sure about rwdata - also COW?
+
+Small experiment measures "parasitic" bbox memory consumption.
+Here we start 1000 "busybox sleep 10" in parallel.
+bbox binary is practically allyesconfig static one,
+built against uclibc:
+
+bash-3.2# nmeter '%t %c %b %m %p %[pn]'
+23:17:28 .......... 0 0 168M 0 147
+23:17:29 .......... 0 0 168M 0 147
+23:17:30 U......... 0 0 168M 1 147
+23:17:31 SU........ 0 188k 181M 244 391
+23:17:32 SSSSUUU... 0 0 223M 757 1147
+23:17:33 UUU....... 0 0 223M 0 1147
+23:17:34 U......... 0 0 223M 1 1147
+23:17:35 .......... 0 0 223M 0 1147
+23:17:36 .......... 0 0 223M 0 1147
+23:17:37 S......... 0 0 223M 0 1147
+23:17:38 .......... 0 0 223M 1 1147
+23:17:39 .......... 0 0 223M 0 1147
+23:17:40 .......... 0 0 223M 0 1147
+23:17:41 .......... 0 0 210M 0 906
+23:17:42 .......... 0 0 168M 1 147
+23:17:43 .......... 0 0 168M 0 147
+
+This requires 55M of memory. Thus 1 trivial busybox applet
+takes 55k of userspace memory (nmeter doesn't account for kernel-side
+allocations). Definitely can be improved.
+
+Thus we should avoid large global data in our applets,
+and should minimize usage of libc functions which implicitly use
+such structures in libc.
+
+ Example 1
+
+One example how to reduce global data usage is in
+archival/libunarchive/decompress_unzip.c:
+
+/* This is somewhat complex-looking arrangement, but it allows
+ * to place decompressor state either in bss or in
+ * malloc'ed space simply by changing #defines below.
+ * Sizes on i386:
+ * text data bss dec hex
+ * 5256 0 108 5364 14f4 - bss
+ * 4915 0 0 4915 1333 - malloc
+ */
+#define STATE_IN_BSS 0
+#define STATE_IN_MALLOC 1
+
+This example completely eliminates globals in that module.
+Required memory is allocated in inflate_gunzip() [its main module]
+and then passed down to all subroutines which need to access globals
+as a parameter.
+
+ Example 2
+
+In case you don't want to pass this additional parameter everywhere,
+take a look at archival/gzip.c. Here all global data is replaced by
+singe global pointer (ptr_to_globals) to allocated storage.
+
+In order to not duplicate ptr_to_globals in every applet, you can
+reuse single common one. It is defined in libbb/messages.c
+as void *ptr_to_globals, but is NOT declared in libbb.h.
+You first define a struct:
+
+struct my_globals { int a; char buf[1000]; };
+
+and then declare that ptr_to_globals is a pointer to it:
+
+extern struct my_globals *ptr_to_globals;
+#define G (*ptr_to_globals)
+
+Linker magic enures that these two merge into single pointer object.
+Now initialize it in <applet>_main():
+
+ ptr_to_globals = xzalloc(sizeof(G));
+
+and you can reference "globals" by G.a, G.buf and so on, in any function.
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