swapon/swapoff: size reduction, cleanup, fixes, improvements
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
Denys Vlasenko
parent
faa9e94db6
commit
a3f326cd66
@ -63,90 +63,142 @@ struct globals {
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} FIX_ALIASING;
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#define G (*(struct globals*)&bb_common_bufsiz1)
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#define g_flags (G.flags)
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#define save_g_flags() int save_g_flags = g_flags
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#define restore_g_flags() g_flags = save_g_flags
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#else
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#define g_flags 0
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#define save_g_flags() ((void)0)
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#define restore_g_flags() ((void)0)
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#endif
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#define INIT_G() do { } while (0)
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#define do_swapoff (applet_name[5] == 'f')
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/* Command line options */
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enum {
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OPTBIT_a, /* -a all */
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IF_FEATURE_SWAPON_DISCARD( OPTBIT_d ,) /* -d discard */
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IF_FEATURE_SWAPON_PRI ( OPTBIT_p ,) /* -p priority */
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OPT_a = 1 << OPTBIT_a,
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OPT_d = IF_FEATURE_SWAPON_DISCARD((1 << OPTBIT_d)) + 0,
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OPT_p = IF_FEATURE_SWAPON_PRI ((1 << OPTBIT_p)) + 0,
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};
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#define OPT_ALL (option_mask32 & OPT_a)
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#define OPT_DISCARD (option_mask32 & OPT_d)
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#define OPT_PRIO (option_mask32 & OPT_p)
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static int swap_enable_disable(char *device)
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{
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int status;
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int err = 0;
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int quiet = 0;
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struct stat st;
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resolve_mount_spec(&device);
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xstat(device, &st);
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#if ENABLE_DESKTOP
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/* test for holes */
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if (S_ISREG(st.st_mode))
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if (st.st_blocks * (off_t)512 < st.st_size)
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bb_error_msg("warning: swap file has holes");
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#endif
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if (do_swapoff) {
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err = swapoff(device);
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/* Don't complain on OPT_ALL if not a swap device or if it doesn't exist */
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quiet = (OPT_ALL && (errno == EINVAL || errno == ENOENT));
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} else {
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/* swapon */
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err = stat(device, &st);
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if (!err) {
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if (ENABLE_DESKTOP && S_ISREG(st.st_mode)) {
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if (st.st_blocks * (off_t)512 < st.st_size) {
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bb_error_msg("%s: file has holes", device);
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return 1;
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}
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}
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err = swapon(device, g_flags);
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/* Don't complain on swapon -a if device is already in use */
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quiet = (OPT_ALL && errno == EBUSY);
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}
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}
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if (applet_name[5] == 'n')
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status = swapon(device, g_flags);
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else
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status = swapoff(device);
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if (status != 0) {
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if (err) {
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if (!quiet)
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bb_simple_perror_msg(device);
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return 1;
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}
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return 0;
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}
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static int do_em_all(void)
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{
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struct mntent *m;
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FILE *f;
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int err;
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#ifdef G
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int cl_flags = g_flags;
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#endif
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f = setmntent("/etc/fstab", "r");
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if (f == NULL)
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bb_perror_msg_and_die("/etc/fstab");
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err = 0;
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while ((m = getmntent(f)) != NULL) {
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if (strcmp(m->mnt_type, MNTTYPE_SWAP) == 0) {
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/* swapon -a should ignore entries with noauto,
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* but swapoff -a should process them */
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if (applet_name[5] != 'n'
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|| hasmntopt(m, MNTOPT_NOAUTO) == NULL
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) {
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#if ENABLE_FEATURE_SWAPON_DISCARD || ENABLE_FEATURE_SWAPON_PRI
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char *p;
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g_flags = cl_flags; /* each swap space might have different flags */
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#if ENABLE_FEATURE_SWAPON_DISCARD
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p = hasmntopt(m, "discard");
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if (p) {
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if (p[7] == '=') {
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if (strncmp(p + 8, "once", 4) == 0 && (p[12] == ',' || p[12] == '\0'))
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g_flags = (g_flags & ~SWAP_FLAG_DISCARD_MASK) | SWAP_FLAG_DISCARD | SWAP_FLAG_DISCARD_ONCE;
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else if (strncmp(p + 8, "pages", 5) == 0 && (p[13] == ',' || p[13] == '\0'))
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g_flags = (g_flags & ~SWAP_FLAG_DISCARD_MASK) | SWAP_FLAG_DISCARD | SWAP_FLAG_DISCARD_PAGES;
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}
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else if (p[7] == ',' || p[7] == '\0')
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static void set_discard_flag(char *s)
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{
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/* Unset the flag first to allow fstab options to override */
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/* options set on the command line */
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g_flags = (g_flags & ~SWAP_FLAG_DISCARD_MASK) | SWAP_FLAG_DISCARD;
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}
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if (!s) /* No optional policy value on the commandline */
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return;
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/* Skip prepended '=' */
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if (*s == '=')
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s++;
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/* For fstab parsing: remove other appended options */
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*strchrnul(s, ',') = '\0';
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if (strcmp(s, "once") == 0)
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g_flags |= SWAP_FLAG_DISCARD_ONCE;
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if (strcmp(s, "pages") == 0)
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g_flags |= SWAP_FLAG_DISCARD_PAGES;
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}
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#else
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#define set_discard_flag(s) ((void)0)
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#endif
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#if ENABLE_FEATURE_SWAPON_PRI
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p = hasmntopt(m, "pri");
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if (p) {
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static void set_priority_flag(char *s)
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{
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unsigned prio;
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/* For fstab parsing: remove other appended options */
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*strchrnul(s, ',') = '\0';
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/* Max allowed 32767 (== SWAP_FLAG_PRIO_MASK) */
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unsigned prio = bb_strtou(p + 4, NULL, 10);
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/* We want to allow "NNNN,foo", thus errno == EINVAL is allowed too */
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if (errno != ERANGE) {
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prio = bb_strtou(s, NULL, 10);
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if (!errno) {
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/* Unset the flag first to allow fstab options to override */
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/* options set on the command line */
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g_flags = (g_flags & ~SWAP_FLAG_PRIO_MASK) | SWAP_FLAG_PREFER |
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MIN(prio, SWAP_FLAG_PRIO_MASK);
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}
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}
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#else
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#define set_priority_flag(s) ((void)0)
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#endif
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static int do_em_all_in_fstab(void)
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{
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struct mntent *m;
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int err = 0;
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FILE *f = xfopen_for_read("/etc/fstab");
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while ((m = getmntent(f)) != NULL) {
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if (strcmp(m->mnt_type, MNTTYPE_SWAP) == 0) {
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/* swapon -a should ignore entries with noauto,
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* but swapoff -a should process them
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*/
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if (do_swapoff || hasmntopt(m, MNTOPT_NOAUTO) == NULL) {
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/* each swap space might have different flags */
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/* save global flags for the next round */
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save_g_flags();
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if (ENABLE_FEATURE_SWAPON_DISCARD) {
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char *p = hasmntopt(m, "discard");
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if (p) {
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/* move to '=' or to end of string */
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p += 7;
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set_discard_flag(p);
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}
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#endif
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#endif
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err += swap_enable_disable(m->mnt_fsname);
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}
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if (ENABLE_FEATURE_SWAPON_PRI) {
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char *p = hasmntopt(m, "pri");
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if (p) {
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set_priority_flag(p + 4);
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}
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}
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err |= swap_enable_disable(m->mnt_fsname);
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restore_g_flags();
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}
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}
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}
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@ -157,74 +209,68 @@ static int do_em_all(void)
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return err;
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}
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static int do_all_in_proc_swaps(void)
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{
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char *line;
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int err = 0;
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FILE *f = fopen_for_read("/proc/swaps");
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/* Don't complain if missing */
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if (f) {
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while ((line = xmalloc_fgetline(f)) != NULL) {
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if (line[0] == '/') {
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*strchrnul(line, ' ') = '\0';
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err |= swap_enable_disable(line);
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}
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free(line);
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}
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if (ENABLE_FEATURE_CLEAN_UP)
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fclose(f);
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}
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return err;
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}
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#define OPTSTR_SWAPON "a" \
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IF_FEATURE_SWAPON_DISCARD("d::") \
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IF_FEATURE_SWAPON_PRI("p:")
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int swap_on_off_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
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int swap_on_off_main(int argc UNUSED_PARAM, char **argv)
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{
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int ret;
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#if ENABLE_FEATURE_SWAPON_DISCARD
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char *discard = NULL;
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#endif
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#if ENABLE_FEATURE_SWAPON_PRI
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unsigned prio;
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#endif
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IF_FEATURE_SWAPON_PRI(char *prio;)
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IF_FEATURE_SWAPON_DISCARD(char *discard = NULL;)
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int ret = 0;
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INIT_G();
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#if !ENABLE_FEATURE_SWAPON_DISCARD && !ENABLE_FEATURE_SWAPON_PRI
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ret = getopt32(argv, "a");
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#else
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#if ENABLE_FEATURE_SWAPON_PRI
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if (applet_name[5] == 'n')
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opt_complementary = "p+";
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#endif
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ret = getopt32(argv, (applet_name[5] == 'n') ?
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#if ENABLE_FEATURE_SWAPON_DISCARD
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"d::"
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#endif
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#if ENABLE_FEATURE_SWAPON_PRI
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"p:"
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#endif
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"a" : "a"
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#if ENABLE_FEATURE_SWAPON_DISCARD
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, &discard
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#endif
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#if ENABLE_FEATURE_SWAPON_PRI
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, &prio
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#endif
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getopt32(argv, do_swapoff ? "a" : OPTSTR_SWAPON
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IF_FEATURE_SWAPON_DISCARD(, &discard)
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IF_FEATURE_SWAPON_PRI(, &prio)
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);
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#endif
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#if ENABLE_FEATURE_SWAPON_DISCARD
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if (ret & 1) { // -d
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if (!discard)
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g_flags |= SWAP_FLAG_DISCARD;
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else if (strcmp(discard, "once") == 0)
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g_flags |= SWAP_FLAG_DISCARD | SWAP_FLAG_DISCARD_ONCE;
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else if (strcmp(discard, "pages") == 0)
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g_flags |= SWAP_FLAG_DISCARD | SWAP_FLAG_DISCARD_PAGES;
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else
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bb_show_usage();
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}
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ret >>= 1;
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#endif
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#if ENABLE_FEATURE_SWAPON_PRI
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if (ret & 1) // -p
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g_flags |= SWAP_FLAG_PREFER |
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MIN(prio, SWAP_FLAG_PRIO_MASK);
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ret >>= 1;
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#endif
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if (ret /* & 1: not needed */) // -a
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return do_em_all();
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argv += optind;
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if (!*argv)
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if (OPT_DISCARD) {
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set_discard_flag(discard);
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}
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if (OPT_PRIO) {
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set_priority_flag(prio);
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}
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if (OPT_ALL) {
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/* swapoff -a does also /proc/swaps */
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if (do_swapoff)
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ret = do_all_in_proc_swaps();
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ret |= do_em_all_in_fstab();
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} else if (!*argv) {
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/* if not -a we need at least one arg */
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bb_show_usage();
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/* ret = 0; redundant */
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do {
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ret += swap_enable_disable(*argv);
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} while (*++argv);
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}
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/* Unset -a now to allow for more messages in swap_enable_disable */
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option_mask32 = option_mask32 & ~OPT_a;
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/* Now process devices on the commandline if any */
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while (*argv) {
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ret |= swap_enable_disable(*argv++);
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}
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return ret;
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}
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