/*      $OpenBSD: swapctl.c,v 1.26 2020/02/11 18:16:38 jca Exp $        */
/*      $NetBSD: swapctl.c,v 1.9 1998/07/26 20:23:15 mycroft Exp $      */

/*
 * Copyright (c) 1996, 1997 Matthew R. Green
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

/*
 * swapctl command:
 *      -A              add all devices listed as `sw' in /etc/fstab
 *      -t [blk|noblk]  if -A, add either all block device or all non-block
 *                      devices
 *      -a <path>       add this device
 *      -d <path>       remove this swap device
 *      -l              list swap devices
 *      -s              short listing of swap devices
 *      -k              use kilobytes
 *      -p <pri>        use this priority
 *      -c <path>       change priority
 *
 * or, if invoked as "swapon" (compatibility mode):
 *
 *      -a              all devices listed as `sw' in /etc/fstab
 *      -t              same as -t above (feature not present in old
 *                      swapon(8) command)
 *      <dev>           add this device
 */

#include <sys/stat.h>
#include <sys/swap.h>
#include <sys/wait.h>

#include <unistd.h>
#include <err.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <limits.h>
#include <string.h>
#include <fstab.h>
#include <util.h>

#include "swapctl.h"

int     command;

/*
 * Commands for swapctl(8).  These are mutually exclusive.
 */
#define CMD_A           0x01    /* process /etc/fstab */
#define CMD_a           0x02    /* add a swap file/device */
#define CMD_c           0x04    /* change priority of a swap file/device */
#define CMD_d           0x08    /* delete a swap file/device */
#define CMD_l           0x10    /* list swap files/devices */
#define CMD_s           0x20    /* summary of swap files/devices */

#define SET_COMMAND(cmd) \
do { \
        if (command) \
                usage(); \
        command = (cmd); \
} while (0)

/*
 * Commands that require a "path" argument at the end of the command
 * line, and the ones which require that none exist.
 */
#define REQUIRE_PATH    (CMD_a | CMD_c | CMD_d)
#define REQUIRE_NOPATH  (CMD_A | CMD_l | CMD_s)

/*
 * Option flags, and the commands with which they are valid.
 */
int     kflag;          /* display in 1K blocks */
#define KFLAG_CMDS      (CMD_l | CMD_s)

int     pflag;          /* priority was specified */
#define PFLAG_CMDS      (CMD_A | CMD_a | CMD_c)

char    *tflag;         /* swap device type (blk or noblk) */
#define TFLAG_CMDS      (CMD_A)

int     pri;            /* uses 0 as default pri */

static  void change_priority(char *);
static  void add_swap(char *);
static  void del_swap(char *);
static  void do_fstab(void);
static  void usage(void);
static  int  swapon_command(int, char **);

extern  char *__progname;       /* from crt0.o */

int
main(int argc, char *argv[])
{
        const char *errstr;
        int     c;

        if (strcmp(__progname, "swapon") == 0)
                return swapon_command(argc, argv);

        while ((c = getopt(argc, argv, "Aacdlkp:st:")) != -1) {
                switch (c) {
                case 'A':
                        SET_COMMAND(CMD_A);
                        break;

                case 'a':
                        SET_COMMAND(CMD_a);
                        break;

                case 'c':
                        SET_COMMAND(CMD_c);
                        break;

                case 'd':
                        SET_COMMAND(CMD_d);
                        break;

                case 'l':
                        SET_COMMAND(CMD_l);
                        break;

                case 'k':
                        kflag = 1;
                        break;

                case 'p':
                        pflag = 1;
                        pri = strtonum(optarg, 0, INT_MAX, &errstr);
                        if (errstr)
                                errx(1, "-p %s: %s", errstr, optarg);
                        break;

                case 's':
                        SET_COMMAND(CMD_s);
                        break;

                case 't':
                        if (tflag != NULL)
                                usage();
                        tflag = optarg;
                        break;

                default:
                        usage();
                        /* NOTREACHED */
                }
        }

        argv += optind;
        argc -= optind;

        /* Did the user specify a command? */
        if (command == 0) {
                if (argc == 0)
                        SET_COMMAND(CMD_l);
                else
                        usage();
        }

        switch (argc) {
        case 0:
                if (command & REQUIRE_PATH)
                        usage();
                break;

        case 1:
                if (command & REQUIRE_NOPATH)
                        usage();
                break;

        default:
                usage();
        }

        /* To change priority, you have to specify one. */
        if ((command == CMD_c) && pflag == 0)
                usage();

        /* Sanity-check -t */
        if (tflag != NULL) {
                if (command != CMD_A)
                        usage();
                if (strcmp(tflag, "blk") != 0 &&
                    strcmp(tflag, "noblk") != 0)
                        usage();
        }

        /* Dispatch the command. */
        switch (command) {
        case CMD_l:
                list_swap(pri, kflag, pflag, 1);
                break;

        case CMD_s:
                list_swap(pri, kflag, pflag, 0);
                break;

        case CMD_c:
                change_priority(argv[0]);
                break;

        case CMD_a:
                add_swap(argv[0]);
                break;

        case CMD_d:
                del_swap(argv[0]);
                break;

        case CMD_A:
                do_fstab();
                break;
        }

        return (0);
}

/*
 * swapon_command: emulate the old swapon(8) program.
 */
int
swapon_command(int argc, char **argv)
{
        int ch, fiztab = 0;

        while ((ch = getopt(argc, argv, "at:")) != -1) {
                switch (ch) {
                case 'a':
                        fiztab = 1;
                        break;
                case 't':
                        if (tflag != NULL)
                                usage();
                        tflag = optarg;
                        break;
                default:
                        goto swapon_usage;
                }
        }
        argc -= optind;
        argv += optind;

        if (fiztab) {
                if (argc)
                        goto swapon_usage;
                /* Sanity-check -t */
                if (tflag != NULL) {
                        if (strcmp(tflag, "blk") != 0 &&
                            strcmp(tflag, "noblk") != 0)
                                usage();
                }
                do_fstab();
                return (0);
        } else if (argc == 0 || tflag != NULL)
                goto swapon_usage;

        while (argc) {
                add_swap(argv[0]);
                argc--;
                argv++;
        }
        return (0);

 swapon_usage:
        fprintf(stderr, "usage: %s -a | path\n", __progname);
        return (1);
}

/*
 * change_priority:  change the priority of a swap device.
 */
void
change_priority(char *path)
{

        if (swapctl(SWAP_CTL, path, pri) == -1)
                warn("%s", path);
}

/*
 * add_swap:  add the pathname to the list of swap devices.
 */
void
add_swap(char *path)
{

        if (swapctl(SWAP_ON, path, pri) == -1)
                if (errno != EBUSY)
                        err(1, "%s", path);
}

/*
 * del_swap:  remove the pathname from the list of swap devices.
 */
void
del_swap(char *path)
{

        if (swapctl(SWAP_OFF, path, pri) == -1)
                err(1, "%s", path);
}

void
do_fstab(void)
{
        struct  fstab *fp;
        char    *s;
        long    priority;
        struct  stat st;
        mode_t  rejecttype = 0;
        int     gotone = 0;

        /*
         * Select which mount point types to reject, depending on the
         * value of the -t parameter.
         */
        if (tflag != NULL) {
                if (strcmp(tflag, "blk") == 0)
                        rejecttype = S_IFREG;
                else if (strcmp(tflag, "noblk") == 0)
                        rejecttype = S_IFBLK;
        }

#define PRIORITYEQ      "priority="
#define NFSMNTPT        "nfsmntpt="
#define PATH_MOUNT      "/sbin/mount_nfs"
        while ((fp = getfsent()) != NULL) {
                const char *spec;

                if (strcmp(fp->fs_type, "sw") != 0)
                        continue;

                spec = fp->fs_spec;

                if ((s = strstr(fp->fs_mntops, PRIORITYEQ)) != NULL) {
                        s += sizeof(PRIORITYEQ) - 1;
                        priority = atol(s);
                } else
                        priority = pri;

                if ((s = strstr(fp->fs_mntops, NFSMNTPT)) != NULL) {
                        char *t;
                        pid_t pid;
                        int status;

                        /*
                         * Skip this song and dance if we're only
                         * doing block devices.
                         */
                        if (rejecttype == S_IFREG)
                                continue;

                        t = strpbrk(s, ",");
                        if (t != 0)
                                *t = '\0';
                        spec = strdup(s + strlen(NFSMNTPT));
                        if (spec == NULL)
                                err(1, "strdup");

                        if (t != 0)
                                *t = ',';

                        if (strlen(spec) == 0) {
                                warnx("empty mountpoint");
                                free((char *)spec);
                                continue;
                        }

                        switch (pid = vfork()) {
                        case -1:        /* error */
                                err(1, "vfork");
                        case 0:
                                execl(PATH_MOUNT, PATH_MOUNT, fp->fs_spec, spec,
                                    (char *)NULL);
                                err(1, "execl");
                        }
                        while (waitpid(pid, &status, 0) == -1)
                                if (errno != EINTR)
                                        err(1, "waitpid");
                        if (status != 0) {
                                warnx("%s: mount failed", fp->fs_spec);
                                free((char *)spec);
                                continue;
                        }
                } else if (isduid(spec, 0)) {
                        if (rejecttype == S_IFBLK)
                                continue;
                } else {
                        /*
                         * Determine blk-ness.  Don't even consider a
                         * mountpoint outside /dev as a block device.
                         */
                        if (rejecttype == S_IFREG) {
                                if (strncmp("/dev/", spec, 5) != 0)
                                        continue;
                        }
                        if (stat(spec, &st) == -1) {
                                warn("%s", spec);
                                continue;
                        }
                        if ((st.st_mode & S_IFMT) == rejecttype)
                                continue;

                        /*
                         * Do not allow fancy objects to be swap areas.
                         */
                        if (!S_ISREG(st.st_mode) &&
                            !S_ISBLK(st.st_mode))
                                continue;
                }

                if (swapctl(SWAP_ON, spec, (int)priority) == -1) {
                        if (errno != EBUSY)
                                warn("%s", spec);
                } else {
                        gotone = 1;
                        printf("%s: adding %s as swap device at priority %d\n",
                            __progname, fp->fs_spec, (int)priority);
                }

                if (spec != fp->fs_spec)
                        free((char *)spec);
        }
        if (gotone == 0)
                exit(1);
}

void
usage(void)
{

        fprintf(stderr, "usage: %s -A [-p priority] [-t blk | noblk]\n",
            __progname);
        fprintf(stderr, "       %s -a [-p priority] path\n", __progname);
        fprintf(stderr, "       %s -c -p priority path\n", __progname);
        fprintf(stderr, "       %s -d path\n", __progname);
        fprintf(stderr, "       %s [[-l] | -s] [-k]\n", __progname);
        exit(1);
}