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swapon/swapoff: size reduction, cleanup, fixes, improvements

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1) real swapon/swapoff handles also devices on the commandline with -a;
2) xstat(device)  in  swap_enable_disable aborts on error when cycling through
   fstab so some devices  are not handled;
3) duplicated code for ENABLE_FEATURE_SWAPON_DISCARD and
   ENABLE_FEATURE_SWAPON_PRI was moved to functions.
4) silence some error messages with -a;
5) minor cleanups and code refactoring reduced the size as per bloat-check:
6) I also added support for /proc/swaps handling to swapoff:
"When the -a flag is given, swapping is disabled on all known  swap  devices
 and  files  (as  found  in  /proc/swaps  or /etc/fstab)."
So now swapoff first cycles through  /proc/swaps and then through fstab
to swapoff all devices.

function                                             old     new   delta
set_discard_flag                                       -     106    +106
swap_enable_disable                                  147     238     +91
set_priority_flag                                      -      79     +79
retrieve_file_data                                   470     467      -3
swap_on_off_main                                     638     418    -220
------------------------------------------------------------------------------
(add/remove: 2/0 grow/shrink: 1/2 up/down: 276/-223)           Total: 53 bytes

Signed-off-by: Tito Ragusa <farmatito@tiscali.it>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Tito Ragusa 2014-03-31 16:39:26 +02:00 committed by Denys Vlasenko
parent faa9e94db6
commit a3f326cd66
1 changed files with 165 additions and 119 deletions
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278
util-linux/swaponoff.c
View File

@ -63,90 +63,142 @@ struct globals {
} FIX_ALIASING; } FIX_ALIASING;
#define G (*(struct globals*)&bb_common_bufsiz1) #define G (*(struct globals*)&bb_common_bufsiz1)
#define g_flags (G.flags) #define g_flags (G.flags)
#define save_g_flags() int save_g_flags = g_flags
#define restore_g_flags() g_flags = save_g_flags
#else #else
#define g_flags 0 #define g_flags 0
#define save_g_flags() ((void)0)
#define restore_g_flags() ((void)0)
#endif #endif
#define INIT_G() do { } while (0) #define INIT_G() do { } while (0)
#define do_swapoff (applet_name[5] == 'f')
/* Command line options */
enum {
OPTBIT_a, /* -a all */
IF_FEATURE_SWAPON_DISCARD( OPTBIT_d ,) /* -d discard */
IF_FEATURE_SWAPON_PRI ( OPTBIT_p ,) /* -p priority */
OPT_a = 1 << OPTBIT_a,
OPT_d = IF_FEATURE_SWAPON_DISCARD((1 << OPTBIT_d)) + 0,
OPT_p = IF_FEATURE_SWAPON_PRI ((1 << OPTBIT_p)) + 0,
};
#define OPT_ALL (option_mask32 & OPT_a)
#define OPT_DISCARD (option_mask32 & OPT_d)
#define OPT_PRIO (option_mask32 & OPT_p)
static int swap_enable_disable(char *device) static int swap_enable_disable(char *device)
{ {
int status; int err = 0;
int quiet = 0;
struct stat st; struct stat st;
resolve_mount_spec(&device); resolve_mount_spec(&device);
xstat(device, &st);
#if ENABLE_DESKTOP if (do_swapoff) {
/* test for holes */ err = swapoff(device);
if (S_ISREG(st.st_mode)) /* Don't complain on OPT_ALL if not a swap device or if it doesn't exist */
if (st.st_blocks * (off_t)512 < st.st_size) quiet = (OPT_ALL && (errno == EINVAL || errno == ENOENT));
bb_error_msg("warning: swap file has holes"); } else {
#endif /* swapon */
err = stat(device, &st);
if (!err) {
if (ENABLE_DESKTOP && S_ISREG(st.st_mode)) {
if (st.st_blocks * (off_t)512 < st.st_size) {
bb_error_msg("%s: file has holes", device);
return 1;
}
}
err = swapon(device, g_flags);
/* Don't complain on swapon -a if device is already in use */
quiet = (OPT_ALL && errno == EBUSY);
}
}
if (applet_name[5] == 'n') if (err) {
status = swapon(device, g_flags); if (!quiet)
else
status = swapoff(device);
if (status != 0) {
bb_simple_perror_msg(device); bb_simple_perror_msg(device);
return 1; return 1;
} }
return 0; return 0;
} }
static int do_em_all(void)
{
struct mntent *m;
FILE *f;
int err;
#ifdef G
int cl_flags = g_flags;
#endif
f = setmntent("/etc/fstab", "r");
if (f == NULL)
bb_perror_msg_and_die("/etc/fstab");
err = 0;
while ((m = getmntent(f)) != NULL) {
if (strcmp(m->mnt_type, MNTTYPE_SWAP) == 0) {
/* swapon -a should ignore entries with noauto,
* but swapoff -a should process them */
if (applet_name[5] != 'n'
|| hasmntopt(m, MNTOPT_NOAUTO) == NULL
) {
#if ENABLE_FEATURE_SWAPON_DISCARD || ENABLE_FEATURE_SWAPON_PRI
char *p;
g_flags = cl_flags; /* each swap space might have different flags */
#if ENABLE_FEATURE_SWAPON_DISCARD #if ENABLE_FEATURE_SWAPON_DISCARD
p = hasmntopt(m, "discard"); static void set_discard_flag(char *s)
if (p) { {
if (p[7] == '=') { /* Unset the flag first to allow fstab options to override */
if (strncmp(p + 8, "once", 4) == 0 && (p[12] == ',' || p[12] == '\0')) /* options set on the command line */
g_flags = (g_flags & ~SWAP_FLAG_DISCARD_MASK) | SWAP_FLAG_DISCARD | SWAP_FLAG_DISCARD_ONCE;
else if (strncmp(p + 8, "pages", 5) == 0 && (p[13] == ',' || p[13] == '\0'))
g_flags = (g_flags & ~SWAP_FLAG_DISCARD_MASK) | SWAP_FLAG_DISCARD | SWAP_FLAG_DISCARD_PAGES;
}
else if (p[7] == ',' || p[7] == '\0')
g_flags = (g_flags & ~SWAP_FLAG_DISCARD_MASK) | SWAP_FLAG_DISCARD; g_flags = (g_flags & ~SWAP_FLAG_DISCARD_MASK) | SWAP_FLAG_DISCARD;
}
if (!s) /* No optional policy value on the commandline */
return;
/* Skip prepended '=' */
if (*s == '=')
s++;
/* For fstab parsing: remove other appended options */
*strchrnul(s, ',') = '\0';
if (strcmp(s, "once") == 0)
g_flags |= SWAP_FLAG_DISCARD_ONCE;
if (strcmp(s, "pages") == 0)
g_flags |= SWAP_FLAG_DISCARD_PAGES;
}
#else
#define set_discard_flag(s) ((void)0)
#endif #endif
#if ENABLE_FEATURE_SWAPON_PRI #if ENABLE_FEATURE_SWAPON_PRI
p = hasmntopt(m, "pri"); static void set_priority_flag(char *s)
if (p) { {
unsigned prio;
/* For fstab parsing: remove other appended options */
*strchrnul(s, ',') = '\0';
/* Max allowed 32767 (== SWAP_FLAG_PRIO_MASK) */ /* Max allowed 32767 (== SWAP_FLAG_PRIO_MASK) */
unsigned prio = bb_strtou(p + 4, NULL, 10); prio = bb_strtou(s, NULL, 10);
/* We want to allow "NNNN,foo", thus errno == EINVAL is allowed too */ if (!errno) {
if (errno != ERANGE) { /* Unset the flag first to allow fstab options to override */
/* options set on the command line */
g_flags = (g_flags & ~SWAP_FLAG_PRIO_MASK) | SWAP_FLAG_PREFER | g_flags = (g_flags & ~SWAP_FLAG_PRIO_MASK) | SWAP_FLAG_PREFER |
MIN(prio, SWAP_FLAG_PRIO_MASK); MIN(prio, SWAP_FLAG_PRIO_MASK);
} }
}
#else
#define set_priority_flag(s) ((void)0)
#endif
static int do_em_all_in_fstab(void)
{
struct mntent *m;
int err = 0;
FILE *f = xfopen_for_read("/etc/fstab");
while ((m = getmntent(f)) != NULL) {
if (strcmp(m->mnt_type, MNTTYPE_SWAP) == 0) {
/* swapon -a should ignore entries with noauto,
* but swapoff -a should process them
*/
if (do_swapoff || hasmntopt(m, MNTOPT_NOAUTO) == NULL) {
/* each swap space might have different flags */
/* save global flags for the next round */
save_g_flags();
if (ENABLE_FEATURE_SWAPON_DISCARD) {
char *p = hasmntopt(m, "discard");
if (p) {
/* move to '=' or to end of string */
p += 7;
set_discard_flag(p);
} }
#endif }
#endif if (ENABLE_FEATURE_SWAPON_PRI) {
err += swap_enable_disable(m->mnt_fsname); char *p = hasmntopt(m, "pri");
if (p) {
set_priority_flag(p + 4);
}
}
err |= swap_enable_disable(m->mnt_fsname);
restore_g_flags();
} }
} }
} }
@ -157,74 +209,68 @@ static int do_em_all(void)
return err; return err;
} }
static int do_all_in_proc_swaps(void)
{
char *line;
int err = 0;
FILE *f = fopen_for_read("/proc/swaps");
/* Don't complain if missing */
if (f) {
while ((line = xmalloc_fgetline(f)) != NULL) {
if (line[0] == '/') {
*strchrnul(line, ' ') = '\0';
err |= swap_enable_disable(line);
}
free(line);
}
if (ENABLE_FEATURE_CLEAN_UP)
fclose(f);
}
return err;
}
#define OPTSTR_SWAPON "a" \
IF_FEATURE_SWAPON_DISCARD("d::") \
IF_FEATURE_SWAPON_PRI("p:")
int swap_on_off_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; int swap_on_off_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int swap_on_off_main(int argc UNUSED_PARAM, char **argv) int swap_on_off_main(int argc UNUSED_PARAM, char **argv)
{ {
int ret; IF_FEATURE_SWAPON_PRI(char *prio;)
#if ENABLE_FEATURE_SWAPON_DISCARD IF_FEATURE_SWAPON_DISCARD(char *discard = NULL;)
char *discard = NULL; int ret = 0;
#endif
#if ENABLE_FEATURE_SWAPON_PRI
unsigned prio;
#endif
INIT_G(); INIT_G();
#if !ENABLE_FEATURE_SWAPON_DISCARD && !ENABLE_FEATURE_SWAPON_PRI getopt32(argv, do_swapoff ? "a" : OPTSTR_SWAPON
ret = getopt32(argv, "a"); IF_FEATURE_SWAPON_DISCARD(, &discard)
#else IF_FEATURE_SWAPON_PRI(, &prio)
#if ENABLE_FEATURE_SWAPON_PRI
if (applet_name[5] == 'n')
opt_complementary = "p+";
#endif
ret = getopt32(argv, (applet_name[5] == 'n') ?
#if ENABLE_FEATURE_SWAPON_DISCARD
"d::"
#endif
#if ENABLE_FEATURE_SWAPON_PRI
"p:"
#endif
"a" : "a"
#if ENABLE_FEATURE_SWAPON_DISCARD
, &discard
#endif
#if ENABLE_FEATURE_SWAPON_PRI
, &prio
#endif
); );
#endif
#if ENABLE_FEATURE_SWAPON_DISCARD
if (ret & 1) { // -d
if (!discard)
g_flags |= SWAP_FLAG_DISCARD;
else if (strcmp(discard, "once") == 0)
g_flags |= SWAP_FLAG_DISCARD | SWAP_FLAG_DISCARD_ONCE;
else if (strcmp(discard, "pages") == 0)
g_flags |= SWAP_FLAG_DISCARD | SWAP_FLAG_DISCARD_PAGES;
else
bb_show_usage();
}
ret >>= 1;
#endif
#if ENABLE_FEATURE_SWAPON_PRI
if (ret & 1) // -p
g_flags |= SWAP_FLAG_PREFER |
MIN(prio, SWAP_FLAG_PRIO_MASK);
ret >>= 1;
#endif
if (ret /* & 1: not needed */) // -a
return do_em_all();
argv += optind; argv += optind;
if (!*argv)
if (OPT_DISCARD) {
set_discard_flag(discard);
}
if (OPT_PRIO) {
set_priority_flag(prio);
}
if (OPT_ALL) {
/* swapoff -a does also /proc/swaps */
if (do_swapoff)
ret = do_all_in_proc_swaps();
ret |= do_em_all_in_fstab();
} else if (!*argv) {
/* if not -a we need at least one arg */
bb_show_usage(); bb_show_usage();
}
/* ret = 0; redundant */ /* Unset -a now to allow for more messages in swap_enable_disable */
do { option_mask32 = option_mask32 & ~OPT_a;
ret += swap_enable_disable(*argv); /* Now process devices on the commandline if any */
} while (*++argv); while (*argv) {
ret |= swap_enable_disable(*argv++);
}
return ret; return ret;
} }