*
* Licensed under GPLv2, see file LICENSE in this source tree.
*/
+//config:config SWAPON
+//config: bool "swapon (4.9 kb)"
+//config: default y
+//config: select PLATFORM_LINUX
+//config: help
+//config: Once you have created some swap space using 'mkswap', you also need
+//config: to enable your swap space with the 'swapon' utility. The 'swapoff'
+//config: utility is used, typically at system shutdown, to disable any swap
+//config: space. If you are not using any swap space, you can leave this
+//config: option disabled.
+//config:
+//config:config FEATURE_SWAPON_DISCARD
+//config: bool "Support discard option -d"
+//config: default y
+//config: depends on SWAPON
+//config: help
+//config: Enable support for discarding swap area blocks at swapon and/or as
+//config: the kernel frees them. This option enables both the -d option on
+//config: 'swapon' and the 'discard' option for swap entries in /etc/fstab.
+//config:
+//config:config FEATURE_SWAPON_PRI
+//config: bool "Support priority option -p"
+//config: default y
+//config: depends on SWAPON
+//config: help
+//config: Enable support for setting swap device priority in swapon.
+//config:
+//config:config SWAPOFF
+//config: bool "swapoff (4.3 kb)"
+//config: default y
+//config: select PLATFORM_LINUX
+//config:
+//config:config FEATURE_SWAPONOFF_LABEL
+//config: bool "Support specifying devices by label or UUID"
+//config: default y
+//config: depends on SWAPON || SWAPOFF
+//config: select VOLUMEID
+//config: help
+//config: This allows for specifying a device by label or uuid, rather than by
+//config: name. This feature utilizes the same functionality as blkid/findfs.
+
+// APPLET_ODDNAME:name main location suid_type help
+//applet:IF_SWAPON( APPLET_ODDNAME(swapon, swap_on_off, BB_DIR_SBIN, BB_SUID_DROP, swapon))
+//applet:IF_SWAPOFF(APPLET_ODDNAME(swapoff, swap_on_off, BB_DIR_SBIN, BB_SUID_DROP, swapoff))
+
+//kbuild:lib-$(CONFIG_SWAPON) += swaponoff.o
+//kbuild:lib-$(CONFIG_SWAPOFF) += swaponoff.o
//usage:#define swapon_trivial_usage
-//usage: "[-a]" IF_FEATURE_SWAPON_PRI(" [-p PRI]") " [DEVICE]"
+//usage: "[-a] [-e]" IF_FEATURE_SWAPON_DISCARD(" [-d[POL]]") IF_FEATURE_SWAPON_PRI(" [-p PRI]") " [DEVICE]"
//usage:#define swapon_full_usage "\n\n"
//usage: "Start swapping on DEVICE\n"
//usage: "\n -a Start swapping on all swap devices"
+//usage: IF_FEATURE_SWAPON_DISCARD(
+//usage: "\n -d[POL] Discard blocks at swapon (POL=once),"
+//usage: "\n as freed (POL=pages), or both (POL omitted)"
+//usage: )
+//usage: "\n -e Silently skip devices that do not exist"
//usage: IF_FEATURE_SWAPON_PRI(
//usage: "\n -p PRI Set swap device priority"
//usage: )
//usage: "\n -a Stop swapping on all swap devices"
#include "libbb.h"
+#include "common_bufsiz.h"
#include <mntent.h>
#ifndef __BIONIC__
# include <sys/swap.h>
#endif
-#if ENABLE_FEATURE_MOUNT_LABEL
+#if ENABLE_FEATURE_SWAPONOFF_LABEL
# include "volume_id.h"
#else
# define resolve_mount_spec(fsname) ((void)0)
# define MNTTYPE_SWAP "swap"
#endif
-#if ENABLE_FEATURE_SWAPON_PRI
+#if ENABLE_FEATURE_SWAPON_DISCARD
+#ifndef SWAP_FLAG_DISCARD
+#define SWAP_FLAG_DISCARD 0x10000
+#endif
+#ifndef SWAP_FLAG_DISCARD_ONCE
+#define SWAP_FLAG_DISCARD_ONCE 0x20000
+#endif
+#ifndef SWAP_FLAG_DISCARD_PAGES
+#define SWAP_FLAG_DISCARD_PAGES 0x40000
+#endif
+#define SWAP_FLAG_DISCARD_MASK \
+ (SWAP_FLAG_DISCARD | SWAP_FLAG_DISCARD_ONCE | SWAP_FLAG_DISCARD_PAGES)
+#endif
+
+
+#if ENABLE_FEATURE_SWAPON_DISCARD || ENABLE_FEATURE_SWAPON_PRI
struct globals {
int flags;
} FIX_ALIASING;
-#define G (*(struct globals*)&bb_common_bufsiz1)
+#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 { setup_common_bufsiz(); } while (0)
+
+#if ENABLE_SWAPOFF
+# if ENABLE_SWAPON
+# define do_swapoff (applet_name[5] == 'f')
+# else
+# define do_swapoff 1
+# endif
+#else
+# define do_swapoff 0
#endif
-#define INIT_G() do { } while (0)
+
+/* Command line options */
+enum {
+ OPTBIT_a, /* -a all */
+ OPTBIT_e, /* -e ifexists */
+ IF_FEATURE_SWAPON_DISCARD( OPTBIT_d ,) /* -d discard */
+ IF_FEATURE_SWAPON_PRI ( OPTBIT_p ,) /* -p priority */
+ OPT_a = 1 << OPTBIT_a,
+ OPT_e = 1 << OPTBIT_e,
+ 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_IFEXISTS (option_mask32 & OPT_e)
+#define OPT_PRIO (option_mask32 & OPT_p)
static int swap_enable_disable(char *device)
{
- int status;
- struct stat st;
+ int err = 0;
+ int quiet = 0;
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 */
+ struct stat st;
+ 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);
+ }
+ /* Don't complain if file does not exist with -e option */
+ if (err && OPT_IFEXISTS && errno == ENOENT)
+ err = 0;
+ }
- if (status != 0) {
+ if (err && !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;
+ /* 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;
- f = setmntent("/etc/fstab", "r");
- if (f == NULL)
- bb_perror_msg_and_die("/etc/fstab");
+ 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
+
+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_PRI
- char *p;
- g_flags = 0; /* each swap space might have different flags */
- p = hasmntopt(m, "pri");
- if (p) {
- /* Max allowed 32767 (==SWAP_FLAG_PRIO_MASK) */
- unsigned int swap_prio = MIN(bb_strtou(p + 4 , NULL, 10), SWAP_FLAG_PRIO_MASK);
- /* We want to allow "NNNN,foo", thus errno == EINVAL is allowed too */
- if (errno != ERANGE) {
- g_flags = SWAP_FLAG_PREFER |
- (swap_prio << SWAP_FLAG_PRIO_SHIFT);
+ * 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
- err += swap_enable_disable(m->mnt_fsname);
+ if (ENABLE_FEATURE_SWAPON_PRI) {
+ char *p = hasmntopt(m, "pri");
+ if (p) {
+ set_priority_flag(p + 4);
+ }
+ }
+ err |= swap_enable_disable(m->mnt_fsname);
+ restore_g_flags();
}
}
}
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 "ae" \
+ 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_FEATURE_SWAPON_PRI(char *prio;)
+ IF_FEATURE_SWAPON_DISCARD(char *discard = NULL;)
+ int ret = 0;
INIT_G();
-#if !ENABLE_FEATURE_SWAPON_PRI
- ret = getopt32(argv, "a");
-#else
- if (applet_name[5] == 'n')
- opt_complementary = "p+";
- ret = getopt32(argv, (applet_name[5] == 'n') ? "ap:" : "a", &g_flags);
-
- if (ret & 2) { // -p
- g_flags = SWAP_FLAG_PREFER |
- ((g_flags & SWAP_FLAG_PRIO_MASK) << SWAP_FLAG_PRIO_SHIFT);
- ret &= 1;
- }
-#endif
-
- if (ret /* & 1: not needed */) // -a
- return do_em_all();
+ getopt32(argv, do_swapoff ? "ae" : 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;
}
projects / oweals / busybox.git / blobdiff