busybox/util-linux/mkswap.c
Denys Vlasenko e6a2f4cc5a libbb: make bb_common_bufsiz1 1 kbyte, add capability to use bss tail for it
The config item is FEATURE_USE_BSS_TAIL. When it is off (default):

function                                             old     new   delta
read_config                                          210     228     +18
doCommands                                          2279    2294     +15
ipneigh_list_or_flush                                763     772      +9
ipaddr_list_or_flush                                1256    1261      +5
display_process_list                                1301    1306      +5
conspy_main                                         1378    1383      +5
do_lzo_compress                                      352     355      +3
do_lzo_decompress                                    565     567      +2
push                                                  46      44      -2
inetd_main                                          2136    2134      -2
uevent_main                                          421     418      -3
addLines                                              97      92      -5
bb_common_bufsiz1                                   8193    1024   -7169
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 8/5 up/down: 62/-7181)        Total: -7119 bytes
   text	   data	    bss	    dec	    hex	filename
 829850	   4086	   9080	 843016	  cdd08	busybox_old
 829901	   4086	   1904	 835891	  cc133	busybox_unstripped

FEATURE_USE_BSS_TAIL=y:

read_config                                          210     228     +18
doCommands                                          2279    2294     +15
ipneigh_list_or_flush                                763     772      +9
ipaddr_list_or_flush                                1256    1261      +5
display_process_list                                1301    1306      +5
conspy_main                                         1378    1383      +5
do_lzo_compress                                      352     355      +3
do_lzo_decompress                                    565     567      +2
inetd_main                                          2136    2134      -2
bb_common_bufsiz1                                   8193       -   -8193
------------------------------------------------------------------------------
(add/remove: 0/1 grow/shrink: 8/1 up/down: 62/-8195)        Total: -8133 bytes
   text	   data	    bss	    dec	    hex	filename
 829850	   4086	   9080	 843016	  cdd08	busybox_old
 829911	   4086	    880	 834877	  cbd3d	busybox_unstripped

FIXME: setup_common_bufsiz() calls are missing.

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
2016-04-21 17:39:11 +02:00

151 lines
4.0 KiB
C

/* vi: set sw=4 ts=4: */
/* mkswap.c - format swap device (Linux v1 only)
*
* Copyright 2006 Rob Landley <rob@landley.net>
*
* Licensed under GPLv2, see file LICENSE in this source tree.
*/
//usage:#define mkswap_trivial_usage
//usage: "[-L LBL] BLOCKDEV [KBYTES]"
//usage:#define mkswap_full_usage "\n\n"
//usage: "Prepare BLOCKDEV to be used as swap partition\n"
//usage: "\n -L LBL Label"
#include "libbb.h"
#include "common_bufsiz.h"
#if ENABLE_SELINUX
static void mkswap_selinux_setcontext(int fd, const char *path)
{
struct stat stbuf;
if (!is_selinux_enabled())
return;
xfstat(fd, &stbuf, path);
if (S_ISREG(stbuf.st_mode)) {
security_context_t newcon;
security_context_t oldcon = NULL;
context_t context;
if (fgetfilecon(fd, &oldcon) < 0) {
if (errno != ENODATA)
goto error;
if (matchpathcon(path, stbuf.st_mode, &oldcon) < 0)
goto error;
}
context = context_new(oldcon);
if (!context || context_type_set(context, "swapfile_t"))
goto error;
newcon = context_str(context);
if (!newcon)
goto error;
/* fsetfilecon_raw is hidden */
if (strcmp(oldcon, newcon) != 0 && fsetfilecon(fd, newcon) < 0)
goto error;
if (ENABLE_FEATURE_CLEAN_UP) {
context_free(context);
freecon(oldcon);
}
}
return;
error:
bb_perror_msg_and_die("SELinux relabeling failed");
}
#else
# define mkswap_selinux_setcontext(fd, path) ((void)0)
#endif
/* from Linux 2.6.23 */
/*
* Magic header for a swap area. ... Note that the first
* kilobyte is reserved for boot loader or disk label stuff.
*/
struct swap_header_v1 {
/* char bootbits[1024]; Space for disklabel etc. */
uint32_t version; /* second kbyte, word 0 */
uint32_t last_page; /* 1 */
uint32_t nr_badpages; /* 2 */
char sws_uuid[16]; /* 3,4,5,6 */
char sws_volume[16]; /* 7,8,9,10 */
uint32_t padding[117]; /* 11..127 */
uint32_t badpages[1]; /* 128 */
/* total 129 32-bit words in 2nd kilobyte */
} FIX_ALIASING;
#define NWORDS 129
#define hdr ((struct swap_header_v1*)bb_common_bufsiz1)
struct BUG_sizes {
char swap_header_v1_wrong[sizeof(*hdr) != (NWORDS * 4) ? -1 : 1];
char bufsiz1_is_too_small[COMMON_BUFSIZE < (NWORDS * 4) ? -1 : 1];
};
/* Stored without terminating NUL */
static const char SWAPSPACE2[sizeof("SWAPSPACE2")-1] ALIGN1 = "SWAPSPACE2";
int mkswap_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int mkswap_main(int argc UNUSED_PARAM, char **argv)
{
int fd;
unsigned pagesize;
off_t len;
const char *label = "";
opt_complementary = "-1"; /* at least one param */
/* TODO: -p PAGESZ, -U UUID */
getopt32(argv, "L:", &label);
argv += optind;
fd = xopen(argv[0], O_WRONLY);
/* Figure out how big the device is */
len = get_volume_size_in_bytes(fd, argv[1], 1024, /*extend:*/ 1);
pagesize = getpagesize();
len -= pagesize;
/* Announce our intentions */
printf("Setting up swapspace version 1, size = %"OFF_FMT"u bytes\n", len);
mkswap_selinux_setcontext(fd, argv[0]);
/* hdr is zero-filled so far. Clear the first kbyte, or else
* mkswap-ing former FAT partition does NOT erase its signature.
*
* util-linux-ng 2.17.2 claims to erase it only if it does not see
* a partition table and is not run on whole disk. -f forces it.
*/
xwrite(fd, hdr, 1024);
/* Fill the header. */
hdr->version = 1;
hdr->last_page = (uoff_t)len / pagesize;
if (ENABLE_FEATURE_MKSWAP_UUID) {
char uuid_string[32];
generate_uuid((void*)hdr->sws_uuid);
bin2hex(uuid_string, hdr->sws_uuid, 16);
/* f.e. UUID=dfd9c173-be52-4d27-99a5-c34c6c2ff55f */
printf("UUID=%.8s" "-%.4s-%.4s-%.4s-%.12s\n",
uuid_string,
uuid_string+8,
uuid_string+8+4,
uuid_string+8+4+4,
uuid_string+8+4+4+4
);
}
safe_strncpy(hdr->sws_volume, label, 16);
/* Write the header. Sync to disk because some kernel versions check
* signature on disk (not in cache) during swapon. */
xwrite(fd, hdr, NWORDS * 4);
xlseek(fd, pagesize - 10, SEEK_SET);
xwrite(fd, SWAPSPACE2, 10);
fsync(fd);
if (ENABLE_FEATURE_CLEAN_UP)
close(fd);
return 0;
}