[git commit] swapon/swapoff: size reduction, cleanup, fixes, improvements
Denys Vlasenko
vda.linux at googlemail.com
Mon Mar 31 14:39:26 UTC 2014
commit: http://git.busybox.net/busybox/commit/?id=a3f326cd6619cadb44cb4bb051b1d4e54bcd3477
branch: http://git.busybox.net/busybox/commit/?id=refs/heads/master
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 at tiscali.it>
Signed-off-by: Denys Vlasenko <vda.linux at googlemail.com>
---
util-linux/swaponoff.c | 276 ++++++++++++++++++++++++++++--------------------
1 files changed, 161 insertions(+), 115 deletions(-)
diff --git a/util-linux/swaponoff.c b/util-linux/swaponoff.c
index a7ad6db..acdb677 100644
--- a/util-linux/swaponoff.c
+++ b/util-linux/swaponoff.c
@@ -63,90 +63,142 @@ struct globals {
} FIX_ALIASING;
#define G (*(struct globals*)&bb_common_bufsiz1)
#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
#define g_flags 0
+#define save_g_flags() ((void)0)
+#define restore_g_flags() ((void)0)
#endif
#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)
{
- int status;
+ int err = 0;
+ int quiet = 0;
struct stat st;
resolve_mount_spec(&device);
- xstat(device, &st);
-
-#if ENABLE_DESKTOP
- /* test for holes */
- if (S_ISREG(st.st_mode))
- if (st.st_blocks * (off_t)512 < st.st_size)
- bb_error_msg("warning: swap file has holes");
-#endif
- if (applet_name[5] == 'n')
- status = swapon(device, g_flags);
- else
- status = swapoff(device);
+ if (do_swapoff) {
+ err = swapoff(device);
+ /* Don't complain on OPT_ALL if not a swap device or if it doesn't exist */
+ quiet = (OPT_ALL && (errno == EINVAL || errno == ENOENT));
+ } else {
+ /* 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 (status != 0) {
- bb_simple_perror_msg(device);
+ if (err) {
+ if (!quiet)
+ bb_simple_perror_msg(device);
return 1;
}
-
return 0;
}
-static int do_em_all(void)
+#if ENABLE_FEATURE_SWAPON_DISCARD
+static void set_discard_flag(char *s)
{
- struct mntent *m;
- FILE *f;
- int err;
-#ifdef G
- int cl_flags = g_flags;
+ /* Unset the flag first to allow fstab options to override */
+ /* options set on the command line */
+ 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
+
+#if ENABLE_FEATURE_SWAPON_PRI
+static void set_priority_flag(char *s)
+{
+ unsigned prio;
+
+ /* For fstab parsing: remove other appended options */
+ *strchrnul(s, ',') = '\0';
+ /* Max allowed 32767 (== SWAP_FLAG_PRIO_MASK) */
+ prio = bb_strtou(s, NULL, 10);
+ if (!errno) {
+ /* 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 |
+ MIN(prio, SWAP_FLAG_PRIO_MASK);
+ }
+}
+#else
+#define set_priority_flag(s) ((void)0)
#endif
- f = setmntent("/etc/fstab", "r");
- if (f == NULL)
- bb_perror_msg_and_die("/etc/fstab");
+static int do_em_all_in_fstab(void)
+{
+ struct mntent *m;
+ int err = 0;
+ FILE *f = xfopen_for_read("/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
- p = hasmntopt(m, "discard");
- if (p) {
- if (p[7] == '=') {
- if (strncmp(p + 8, "once", 4) == 0 && (p[12] == ',' || p[12] == '\0'))
- 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;
+ * 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);
}
- else if (p[7] == ',' || p[7] == '\0')
- g_flags = (g_flags & ~SWAP_FLAG_DISCARD_MASK) | SWAP_FLAG_DISCARD;
}
-#endif
-#if ENABLE_FEATURE_SWAPON_PRI
- p = hasmntopt(m, "pri");
- if (p) {
- /* Max allowed 32767 (== SWAP_FLAG_PRIO_MASK) */
- unsigned prio = bb_strtou(p + 4, NULL, 10);
- /* We want to allow "NNNN,foo", thus errno == EINVAL is allowed too */
- if (errno != ERANGE) {
- g_flags = (g_flags & ~SWAP_FLAG_PRIO_MASK) | SWAP_FLAG_PREFER |
- MIN(prio, SWAP_FLAG_PRIO_MASK);
+ if (ENABLE_FEATURE_SWAPON_PRI) {
+ char *p = hasmntopt(m, "pri");
+ if (p) {
+ set_priority_flag(p + 4);
}
}
-#endif
-#endif
- err += swap_enable_disable(m->mnt_fsname);
+ err |= swap_enable_disable(m->mnt_fsname);
+ restore_g_flags();
}
}
}
@@ -157,74 +209,68 @@ static int do_em_all(void)
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 UNUSED_PARAM, char **argv)
{
- int ret;
-#if ENABLE_FEATURE_SWAPON_DISCARD
- char *discard = NULL;
-#endif
-#if ENABLE_FEATURE_SWAPON_PRI
- unsigned prio;
-#endif
+ IF_FEATURE_SWAPON_PRI(char *prio;)
+ IF_FEATURE_SWAPON_DISCARD(char *discard = NULL;)
+ int ret = 0;
INIT_G();
-#if !ENABLE_FEATURE_SWAPON_DISCARD && !ENABLE_FEATURE_SWAPON_PRI
- ret = getopt32(argv, "a");
-#else
-#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();
+ getopt32(argv, do_swapoff ? "a" : OPTSTR_SWAPON
+ IF_FEATURE_SWAPON_DISCARD(, &discard)
+ IF_FEATURE_SWAPON_PRI(, &prio)
+ );
argv += optind;
- if (!*argv)
- bb_show_usage();
- /* ret = 0; redundant */
- do {
- ret += swap_enable_disable(*argv);
- } while (*++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();
+ }
+ /* Unset -a now to allow for more messages in swap_enable_disable */
+ option_mask32 = option_mask32 & ~OPT_a;
+ /* Now process devices on the commandline if any */
+ while (*argv) {
+ ret |= swap_enable_disable(*argv++);
+ }
return ret;
}
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