Add 'swapctl' - as a hardlink to swapon/swapoff, and augment swapon with
swapctl functionality. The idea is to create a swapctl command that is fairly close to the OpenBSD and NetBSD version. FreeBSD does not implement swap priority (and it would be a mistake if we did) so we didn't bother with that part of it. Submitted by: Eirik Nygaard <eirikn@bluezone.no> Augmented by: dillon (extensively) Reviewed by: David Schultz <dschultz@uclink.Berkeley.EDU>
This commit is contained in:
Matthew Dillon
parent
63100290f3
commit
a420c8119a
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=108375
@ -4,6 +4,8 @@
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PROG= swapon
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MAN= swapon.8
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LINKS= ${BINDIR}/swapon ${BINDIR}/swapoff
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LINKS+= ${BINDIR}/swapon ${BINDIR}/swapctl
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MLINKS= swapon.8 swapoff.8
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MLINKS+=swapon.8 swapctl.8
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.include <bsd.prog.mk>
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@ -43,39 +43,94 @@
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.Fl a
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.Nm swap[on|off]
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.Ar special_file ...
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.Nm swapctl
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.Fl lshk
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.Nm swapctl
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.Fl AU
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.Nm swapctl
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.Fl a
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.Ar special_file ...
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.Nm swapctl
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.Fl d
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.Ar special_file ...
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.Sh DESCRIPTION
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The
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.Nm swap[on,off,ctl]
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utilties are used to control swap devices in the system. At boot time all
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swap entries in
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.Pa /etc/fstab
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are added automatically when the system goes multi-user.
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Swap devices are interleaved and kernels are typically configured
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to handle a maximum of 4 swap devices. There is no priority mechanism.
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.Pp
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The
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.Nm swapon
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utility is used to specify additional devices on which paging and swapping
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are to take place.
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The system begins by swapping and paging on only a single device
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so that only one disk is required at bootstrap time.
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Calls to
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.Nm swapon
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normally occur in the system multi-user initialization file
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.Pa /etc/rc
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making all swap devices available, so that the paging and swapping
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activity is interleaved across several devices.
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utility adds the specified swap devices to the system. If the
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.Fl a
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option is used, all swap devices in
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.Pa /etc/fstab
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will be added, unless their ``noauto'' option is also set.
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.Pp
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The
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.Nm swapoff
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utility disables paging and swapping on a device.
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Calls to
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.Nm swapoff
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succeed only if disabling the device would leave enough
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remaining virtual memory to accomodate all running programs.
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.Pp
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Normally, the first form is used:
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.Bl -tag -width indent
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.It Fl a
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All devices marked as ``sw''
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swap devices in
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utility removes the specified swap devices from the system. If the
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.Fl a
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option is used, all swap devices in
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.Pa /etc/fstab
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are added to or removed from the pool of available swap
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unless their ``noauto'' option is also set.
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.El
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will be removed, unless their ``noauto'' option is also set.
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Note that
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.Nm swapoff
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will fail and refuse to remove a swap device if there is insufficient
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VM (memory + remaining swap devices) to run the system.
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.Nm Swapoff
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must move swapped pages out of the device being removed which could
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lead to high system loads for a period of time, depending on how
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much data has been swapped out to that device.
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.Pp
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The second form is used to configure or disable individual devices.
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The
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.Nm swapctl
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utility exists primarily for those familiar with other BSDs and may be
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used to add, remove, or list swap. Note that the
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.Fl a
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option is used diferently in
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.Nm swapctl
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and indicates that a specific list of devices should be added.
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The
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.Fl d
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option indicates that a specific list should be removed. The
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.Fl A
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and
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.Fl D
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options to
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.Nm swapctl
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operate on all swap entries in
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.Pa /etc/fstab
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which do not have their ``noauto'' option set.
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.Pp
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Swap information can be generated using the
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.Nm swapinfo
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program,
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.Nm pstat
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.Fl s ,
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or
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.Nm swapctl
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.Fl lshk .
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The
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.Nm swapctl
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utility has the following options for listing swap:
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.Bl -tag -width indent
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.It Fl l
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List the devices making up system swap.
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.It Fl s
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Print a summary line for system swap.
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.It Fl h
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Output values in megabytes.
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.It Fl k
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Output values in kilobytes.
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.Pp
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The BLOCKSIZE environment variable is used if not specifically
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overridden. 512 byte blocks are used by default.
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.El
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.Sh SEE ALSO
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.Xr swapon 2 ,
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.Xr fstab 5 ,
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@ -45,6 +45,11 @@ static const char rcsid[] =
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"$FreeBSD$";
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#endif /* not lint */
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#include <sys/stat.h>
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#include <sys/param.h>
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#include <sys/user.h>
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#include <sys/sysctl.h>
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#include <err.h>
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#include <errno.h>
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#include <fstab.h>
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@ -52,59 +57,122 @@ static const char rcsid[] =
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include <fcntl.h>
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static void usage(const char *);
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static int is_swapoff(const char *);
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int swap_on_off(char *name, int ignoreebusy, int do_swapoff);
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static void usage(void);
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static int swap_on_off(char *name, int ignoreebusy);
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static void swaplist(int, int, int);
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enum { SWAPON, SWAPOFF, SWAPCTL } orig_prog, which_prog = SWAPCTL;
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int
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main(int argc, char **argv)
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{
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struct fstab *fsp;
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char *ptr;
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int stat;
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int ch, doall;
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int do_swapoff;
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char *pname = argv[0];
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do_swapoff = is_swapoff(pname);
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int sflag = 0, lflag = 0, hflag = 0;
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if ((ptr = strrchr(argv[0], '/')) == NULL)
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ptr = argv[0];
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if (strstr(ptr, "swapon"))
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which_prog = SWAPON;
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else if (strstr(ptr, "swapoff"))
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which_prog = SWAPOFF;
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orig_prog = which_prog;
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doall = 0;
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while ((ch = getopt(argc, argv, "a")) != -1)
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switch((char)ch) {
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while ((ch = getopt(argc, argv, "AadlhksU")) != -1) {
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switch(ch) {
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case 'A':
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if (which_prog == SWAPCTL) {
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doall = 1;
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which_prog = SWAPON;
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} else {
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usage();
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}
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break;
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case 'a':
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doall = 1;
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if (which_prog == SWAPON || which_prog == SWAPOFF)
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doall = 1;
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else
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which_prog = SWAPON;
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break;
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case 'd':
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if (which_prog == SWAPCTL)
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which_prog = SWAPOFF;
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else
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usage();
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break;
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case 's':
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sflag = 1;
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break;
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case 'l':
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lflag = 1;
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break;
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case 'h':
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hflag = 'M';
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break;
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case 'k':
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hflag = 'K';
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break;
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case 'U':
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if (which_prog == SWAPCTL) {
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doall = 1;
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which_prog = SWAPOFF;
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} else {
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usage();
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}
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break;
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case '?':
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default:
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usage(pname);
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usage();
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}
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}
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argv += optind;
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stat = 0;
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if (doall)
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while ((fsp = getfsent()) != NULL) {
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if (strcmp(fsp->fs_type, FSTAB_SW))
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continue;
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if (strstr(fsp->fs_mntops, "noauto"))
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continue;
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if (swap_on_off(fsp->fs_spec, 1, do_swapoff))
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stat = 1;
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else
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printf("%s: %sing %s as swap device\n",
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pname, do_swapoff ? "remov" : "add",
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fsp->fs_spec);
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if (which_prog == SWAPON || which_prog == SWAPOFF) {
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if (doall) {
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while ((fsp = getfsent()) != NULL) {
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if (strcmp(fsp->fs_type, FSTAB_SW))
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continue;
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if (strstr(fsp->fs_mntops, "noauto"))
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continue;
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if (swap_on_off(fsp->fs_spec, 0)) {
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stat = 1;
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} else {
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printf("%s: %sing %s as swap device\n",
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getprogname(), which_prog == SWAPOFF ? "remov" : "add",
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fsp->fs_spec);
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}
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}
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}
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else if (!*argv)
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usage(pname);
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for (; *argv; ++argv)
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stat |= swap_on_off(*argv, 0, do_swapoff);
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else if (!*argv)
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usage();
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for (; *argv; ++argv) {
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if (swap_on_off(*argv, 0)) {
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stat = 1;
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} else if (orig_prog == SWAPCTL) {
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printf("%s: %sing %s as swap device\n",
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getprogname(), which_prog == SWAPOFF ? "remov" : "add",
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*argv);
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}
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}
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} else {
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if (lflag || sflag)
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swaplist(lflag, sflag, hflag);
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else
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usage();
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}
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exit(stat);
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}
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int
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swap_on_off(char *name, int ignoreebusy, int do_swapoff)
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static int
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swap_on_off(char *name, int ignoreebusy)
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{
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if ((do_swapoff ? swapoff(name) : swapon(name)) == -1) {
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if ((which_prog == SWAPOFF ? swapoff(name) : swapon(name)) == -1) {
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switch (errno) {
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case EBUSY:
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if (!ignoreebusy)
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@ -120,23 +188,90 @@ swap_on_off(char *name, int ignoreebusy, int do_swapoff)
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}
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static void
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usage(const char *pname)
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usage(void)
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{
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fprintf(stderr, "usage: %s [-a] [special_file ...]\n", pname);
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fprintf(stderr, "usage: %s ", getprogname());
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switch(orig_prog) {
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case SWAPOFF:
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fprintf(stderr, "[-a] [special_file ...]\n");
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break;
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case SWAPON:
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fprintf(stderr, "[-a] [special_file ...]\n");
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break;
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case SWAPCTL:
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fprintf(stderr, "[-lshAU] [-a/-d special_file ...]\n");
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break;
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}
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exit(1);
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}
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static int
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is_swapoff(const char *s)
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static void
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swaplist(int lflag, int sflag, int hflag)
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{
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const char *u;
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if ((u = strrchr(s, '/')) != NULL)
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++u;
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else
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u = s;
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if (strcmp(u, "swapoff") == 0)
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return 1;
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else
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return 0;
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size_t mibsize, size;
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struct xswdev xsw;
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int mib[16], n, pagesize;
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size_t hlen;
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long blocksize;
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long long total = 0;
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long long used = 0;
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long long tmp_total;
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long long tmp_used;
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pagesize = getpagesize();
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switch(hflag) {
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case 'K':
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blocksize = 1024;
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hlen = 10;
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break;
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case 'M':
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blocksize = 1024 * 1024;
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hlen = 10;
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break;
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default:
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getbsize(&hlen, &blocksize);
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break;
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}
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mibsize = sizeof mib / sizeof mib[0];
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if (sysctlnametomib("vm.swap_info", mib, &mibsize) == -1)
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err(1, "sysctlnametomib()");
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if (lflag) {
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char buf[32];
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snprintf(buf, sizeof(buf), "%ld-blocks", blocksize);
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printf("%-13s %*s %*s\n",
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"Device:",
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hlen, buf,
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hlen, "Used:");
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}
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for (n = 0; ; ++n) {
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mib[mibsize] = n;
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size = sizeof xsw;
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if (sysctl(mib, mibsize + 1, &xsw, &size, NULL, NULL) == -1)
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break;
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if (xsw.xsw_version != XSWDEV_VERSION)
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errx(1, "xswdev version mismatch");
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tmp_total = (long long)xsw.xsw_nblks * pagesize / blocksize;
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tmp_used = (long long)xsw.xsw_used * pagesize / blocksize;
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total += tmp_total;
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used += tmp_used;
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if (lflag) {
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printf("/dev/%-8s %*lld %*lld\n",
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devname(xsw.xsw_dev, S_IFCHR),
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hlen, tmp_total,
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hlen, tmp_used);
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}
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}
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if (errno != ENOENT)
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err(1, "sysctl()");
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if (sflag) {
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printf("Total: %*lld %*lld\n",
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hlen, total,
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hlen, used);
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}
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}
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