/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright (c) 1998, 2010, Oracle and/or its affiliates. All rights reserved.
 * Copyright 2015 Nexenta Systems, Inc. All rights reserved.
 * Copyright 2020 Joyent, Inc.
 * Copyright 2024 MNX Cloud, Inc.
 */

#include <sys/types.h>
#include <sys/stat.h>
#include <sys/swap.h>
#include <sys/dumpadm.h>
#include <sys/utsname.h>

#include <unistd.h>
#include <string.h>
#include <stdlib.h>
#include <stdio.h>
#include <fcntl.h>
#include <errno.h>
#include <libdiskmgt.h>
#include <libzfs.h>
#include <libzutil.h>
#include <uuid/uuid.h>

#include "dconf.h"
#include "minfree.h"
#include "utils.h"
#include "swap.h"

typedef struct dc_token {
        const char *tok_name;
        int (*tok_parse)(dumpconf_t *, char *);
        int (*tok_print)(const dumpconf_t *, FILE *);
} dc_token_t;


static int print_device(const dumpconf_t *, FILE *);
static int print_savdir(const dumpconf_t *, FILE *);
static int print_content(const dumpconf_t *, FILE *);
static int print_enable(const dumpconf_t *, FILE *);
static int print_csave(const dumpconf_t *, FILE *);

static const dc_token_t tokens[] = {
        { "DUMPADM_DEVICE", dconf_str2device, print_device },
        { "DUMPADM_SAVDIR", dconf_str2savdir, print_savdir },
        { "DUMPADM_CONTENT", dconf_str2content, print_content },
        { "DUMPADM_ENABLE", dconf_str2enable, print_enable },
        { "DUMPADM_CSAVE", dconf_str2csave, print_csave },
        { NULL, NULL, NULL }
};

static const char DC_STR_ON[] = "on";           /* On string */
static const char DC_STR_OFF[] = "off";         /* Off string */
static const char DC_STR_YES[] = "yes";         /* Enable on string */
static const char DC_STR_NO[] = "no";           /* Enable off string */
static const char DC_STR_SWAP[] = "swap";       /* Default dump device */
static const char DC_STR_NONE[] = "none";

/* The pages included in the dump */
static const char DC_STR_KERNEL[] = "kernel";   /* Kernel only */
static const char DC_STR_CURPROC[] = "curproc"; /* Kernel + current process */
static const char DC_STR_ALL[] = "all";         /* All pages */

/*
 * Permissions and ownership for the configuration file:
 */
#define DC_OWNER        0                               /* Uid 0 (root) */
#define DC_GROUP        1                               /* Gid 1 (other) */
#define DC_PERM (S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH) /* Mode 0644 */

static void
dconf_init(dumpconf_t *dcp, int dcmode)
{
        struct utsname ut;

        /*
         * Default device for dumps is 'swap' (appropriate swap device),
         * and default savecore directory is /var/crash/`uname -n`,
         * which is compatible with pre-dumpadm behavior.
         */
        (void) strcpy(dcp->dc_device, DC_STR_SWAP);
        (void) strcpy(dcp->dc_savdir, "/var/crash");

        if (uname(&ut) != -1) {
                (void) strcat(dcp->dc_savdir, "/");
                (void) strcat(dcp->dc_savdir, ut.nodename);
        }

        /*
         * Default is contents kernel, savecore enabled on reboot,
         * savecore saves compressed core files.
         */
        dcp->dc_cflags = DUMP_KERNEL;
        dcp->dc_enable = DC_ON;
        dcp->dc_csave = DC_COMPRESSED;

        dcp->dc_mode = dcmode;
        dcp->dc_conf_fp = NULL;
        dcp->dc_conf_fd = -1;
        dcp->dc_dump_fd = -1;
        dcp->dc_readonly = false;
        dcp->dc_parsable = false;
        dcp->dc_headers = true;
}

int
dconf_open(dumpconf_t *dcp, const char *dpath, const char *fpath, int dcmode)
{
        char buf[BUFSIZ];
        int line;
        const char *fpmode = "r+";

        dconf_init(dcp, dcmode);

        if ((dcp->dc_dump_fd = open(dpath, O_RDWR)) == -1) {
                warn(gettext("failed to open %s"), dpath);
                return (-1);
        }

        if ((dcp->dc_conf_fd = open(fpath, O_RDWR | O_CREAT, DC_PERM)) == -1) {
                /*
                 * Attempt to open the file read-only.
                 */
                if ((dcp->dc_conf_fd = open(fpath, O_RDONLY)) == -1) {
                        warn(gettext("failed to open %s"), fpath);
                        return (-1);
                }

                dcp->dc_readonly = true;
                fpmode = "r";
        }

        if ((dcp->dc_conf_fp = fdopen(dcp->dc_conf_fd, fpmode)) == NULL) {
                warn(gettext("failed to open stream for %s"), fpath);
                return (-1);
        }

        /*
         * If we're in override mode, the current kernel settings override the
         * default settings and anything invalid in the configuration file.
         */
        if (dcmode == DC_OVERRIDE)
                (void) dconf_getdev(dcp);

        for (line = 1; fgets(buf, BUFSIZ, dcp->dc_conf_fp) != NULL; line++) {

                char name[BUFSIZ], value[BUFSIZ];
                const dc_token_t *tokp;
                int len;

                if (buf[0] == '#' || buf[0] == '\n')
                        continue;

                /*
                 * Look for "name=value", with optional whitespace on either
                 * side, terminated by a newline, and consuming the whole line.
                 */
                /* LINTED - unbounded string specifier */
                if (sscanf(buf, " %[^=]=%s \n%n", name, value, &len) == 2 &&
                    name[0] != '\0' && value[0] != '\0' && len == strlen(buf)) {
                        /*
                         * Locate a matching token in the tokens[] table,
                         * and invoke its parsing function.
                         */
                        for (tokp = tokens; tokp->tok_name != NULL; tokp++) {
                                if (strcmp(name, tokp->tok_name) == 0) {
                                        if (tokp->tok_parse(dcp, value) == -1) {
                                                warn(gettext("\"%s\", line %d: "
                                                    "warning: invalid %s\n"),
                                                    fpath, line, name);
                                        }
                                        break;
                                }
                        }

                        /*
                         * If we hit the end of the tokens[] table,
                         * no matching token was found.
                         */
                        if (tokp->tok_name == NULL) {
                                warn(gettext("\"%s\", line %d: warning: "
                                    "invalid token: %s\n"), fpath, line, name);
                        }

                } else {
                        warn(gettext("\"%s\", line %d: syntax error\n"),
                            fpath, line);
                }
        }

        /*
         * If we're not in override mode, the current kernel settings
         * override the settings read from the configuration file.
         */
        if (dcmode == DC_CURRENT)
                return (dconf_getdev(dcp));

        return (0);
}

int
dconf_getdev(dumpconf_t *dcp)
{
        int status = 0;

        if ((dcp->dc_cflags = ioctl(dcp->dc_dump_fd, DIOCGETCONF, 0)) == -1) {
                warn(gettext("failed to get kernel dump settings"));
                status = -1;
        }

        if (ioctl(dcp->dc_dump_fd, DIOCGETDEV, dcp->dc_device) == -1) {
                if (errno != ENODEV) {
                        warn(gettext("failed to get dump device"));
                        status = -1;
                } else
                        dcp->dc_device[0] = '\0';
        }

        return (status);
}

int
dconf_close(dumpconf_t *dcp)
{
        if (fclose(dcp->dc_conf_fp) == 0) {
                (void) close(dcp->dc_dump_fd);
                return (0);
        }
        return (-1);
}

int
dconf_write(dumpconf_t *dcp)
{
        const dc_token_t *tokp;

        if (fseeko(dcp->dc_conf_fp, (off_t)0, SEEK_SET) == -1) {
                warn(gettext("failed to seek config file"));
                return (-1);
        }

        if (ftruncate(dcp->dc_conf_fd, (off_t)0) == -1) {
                warn(gettext("failed to truncate config file"));
                return (-1);
        }

        (void) fputs("#\n# dumpadm.conf\n#\n"
            "# Configuration parameters for system crash dump.\n"
            "# Do NOT edit this file by hand -- use dumpadm(8) instead.\n"
            "#\n", dcp->dc_conf_fp);

        for (tokp = tokens; tokp->tok_name != NULL; tokp++) {
                if (fprintf(dcp->dc_conf_fp, "%s=", tokp->tok_name) == -1 ||
                    tokp->tok_print(dcp, dcp->dc_conf_fp) == -1) {
                        warn(gettext("failed to write token"));
                        return (-1);
                }
        }

        if (fflush(dcp->dc_conf_fp) != 0)
                warn(gettext("warning: failed to flush config file"));

        if (fsync(dcp->dc_conf_fd) == -1)
                warn(gettext("warning: failed to sync config file to disk"));

        if (fchmod(dcp->dc_conf_fd, DC_PERM) == -1)
                warn(gettext("warning: failed to reset mode on config file"));

        if (fchown(dcp->dc_conf_fd, DC_OWNER, DC_GROUP) == -1)
                warn(gettext("warning: failed to reset owner on config file"));

        return (0);
}

static int
open_stat64(const char *path, struct stat64 *stp)
{
        int fd = open64(path, O_RDONLY);

        if (fd >= 0) {
                int status = fstat64(fd, stp);
                (void) close(fd);
                return (status);
        }

        return (-1);
}

static int
dconf_swap_compare(const swapent_t *s1, const swapent_t *s2)
{
        struct stat64 st1, st2;

        int prefer_s1 = -1;     /* Return value to move s1 left (s1 < s2) */
        int prefer_s2 = 1;      /* Return value to move s2 left (s1 > s2) */

        /*
         * First try: open and fstat each swap entry.  If either system
         * call fails, arbitrarily prefer the other entry.
         */
        if (open_stat64(s1->ste_path, &st1) == -1)
                return (prefer_s2);

        if (open_stat64(s2->ste_path, &st2) == -1)
                return (prefer_s1);

        /*
         * Second try: if both entries are block devices, or if
         * neither is a block device, prefer the larger.
         */
        if (S_ISBLK(st1.st_mode) == S_ISBLK(st2.st_mode)) {
                if (st2.st_size > st1.st_size)
                        return (prefer_s2);
                return (prefer_s1);
        }

        /*
         * Third try: prefer the entry that is a block device.
         */
        if (S_ISBLK(st2.st_mode))
                return (prefer_s2);
        return (prefer_s1);
}

static int
dconf_dev_ioctl(dumpconf_t *dcp, int cmd)
{
        if (ioctl(dcp->dc_dump_fd, cmd, dcp->dc_device) == 0)
                return (0);

        switch (errno) {
        case ENOTSUP:
                warn(gettext("dumps not supported on %s\n"), dcp->dc_device);
                break;
        case EBUSY:
                warn(gettext("device %s is already in use\n"), dcp->dc_device);
                break;
        case EBADR:
                /* ZFS pool is too fragmented to support a dump device */
                warn(gettext("device %s is too fragmented to be used as "
                    "a dump device\n"), dcp->dc_device);
                break;
        default:
                /*
                 * NOTE: The stmsboot(8) command's boot-up script parses this
                 * error to get the dump device name. If you change the format
                 * of this message, make sure that stmsboot(8) is in sync.
                 */
                warn(gettext("cannot use %s as dump device"), dcp->dc_device);
        }
        return (-1);
}

int
dconf_update(dumpconf_t *dcp, int checkinuse)
{
        int             oconf;
        int             error;
        char            *msg;

        error = 0;

        if (checkinuse && (dm_inuse(dcp->dc_device, &msg, DM_WHO_DUMP,
            &error) || error)) {
                if (error != 0) {
                        warn(gettext("failed to determine if %s is"
                            " in use"), dcp->dc_device);
                } else {
                        warn(msg);
                        free(msg);
                        return (-1);
                }
        }

        /*
         * Save the existing dump configuration in case something goes wrong.
         */
        if ((oconf = ioctl(dcp->dc_dump_fd, DIOCGETCONF, 0)) == -1) {
                warn(gettext("failed to get kernel dump configuration"));
                return (-1);
        }

        oconf &= DUMP_CONTENT;
        dcp->dc_cflags &= DUMP_CONTENT;

        if (ioctl(dcp->dc_dump_fd, DIOCSETCONF, dcp->dc_cflags) == -1) {
                warn(gettext("failed to update kernel dump configuration"));
                return (-1);
        }

        if (strcmp(dcp->dc_device, DC_STR_SWAP) == 0) {
                swaptbl_t *swt;
                int i;

                if ((swt = swap_list()) == NULL)
                        goto err;

                if (swt->swt_n == 0) {
                        warn(gettext("no swap devices are available\n"));
                        free(swt);
                        goto err;
                }

                qsort(&swt->swt_ent[0], swt->swt_n, sizeof (swapent_t),
                    (int (*)(const void *, const void *))dconf_swap_compare);

                /*
                 * Iterate through the prioritized list of swap entries,
                 * trying to configure one as the dump device.
                 */
                for (i = 0; i < swt->swt_n; i++) {
                        if (ioctl(dcp->dc_dump_fd, DIOCSETDEV,
                            swt->swt_ent[i].ste_path) == 0) {
                                (void) strcpy(dcp->dc_device,
                                    swt->swt_ent[i].ste_path);
                                break;
                        }
                }

                if (i == swt->swt_n) {
                        warn(gettext("no swap devices could be configured "
                            "as the dump device\n"));
                        free(swt);
                        goto err;
                }
                free(swt);

        } else if (strcmp(dcp->dc_device, DC_STR_NONE) == 0) {
                if (ioctl(dcp->dc_dump_fd, DIOCRMDEV, NULL) == -1) {
                        warn(gettext("failed to remove dump device"));
                        return (-1);
                }
        } else if (dcp->dc_device[0] != '\0') {
                /*
                 * If we're not in forcible update mode, then fail the change
                 * if the selected device cannot be used as the dump device,
                 * or if it is not big enough to hold the dump.
                 */
                if (dcp->dc_mode == DC_CURRENT) {
                        struct stat64 st;
                        uint64_t d;

                        if (dconf_dev_ioctl(dcp, DIOCTRYDEV) == -1)
                                goto err;

                        if (open_stat64(dcp->dc_device, &st) == -1) {
                                warn(gettext("failed to access %s"),
                                    dcp->dc_device);
                                goto err;
                        }

                        if ((error = zvol_check_dump_config(
                            dcp->dc_device)) > 0)
                                goto err;
                        if (ioctl(dcp->dc_dump_fd, DIOCGETDUMPSIZE, &d) == -1) {
                                warn(gettext("failed to get kernel dump size"));
                                goto err;
                        }

                        if (st.st_size < d) {
                                warn(gettext("dump device %s is too small to "
                                    "hold a system dump\ndump size %llu "
                                    "bytes, device size %lld bytes\n"),
                                    dcp->dc_device, d, st.st_size);
                                goto err;
                        }
                }

                if (dconf_dev_ioctl(dcp, DIOCSETDEV) == -1)
                        goto err;
        }

        /*
         * Now that we've updated the dump device, we need to issue another
         * ioctl to re-read the config flags to determine whether we
         * obtained DUMP_EXCL access on our dump device.
         */
        if ((dcp->dc_cflags = ioctl(dcp->dc_dump_fd, DIOCGETCONF, 0)) == -1) {
                warn(gettext("failed to re-read kernel dump configuration"));
                return (-1);
        }

        return (0);

err:
        (void) ioctl(dcp->dc_dump_fd, DIOCSETCONF, oconf);
        return (-1);
}

int
dconf_write_uuid(dumpconf_t *dcp)
{
        char uuidstr[36 + 1];
        uuid_t uu;
        int err;

        uuid_generate(uu);
        uuid_unparse(uu, uuidstr);

        err = ioctl(dcp->dc_dump_fd, DIOCSETUUID, uuidstr);

        if (err)
                warn(gettext("kernel image uuid write failed"));

        return (err == 0);
}

int
dconf_get_dumpsize(dumpconf_t *dcp)
{
        char buf[32];
        uint64_t d;

        if (ioctl(dcp->dc_dump_fd, DIOCGETDUMPSIZE, &d) == -1) {
                warn(gettext("failed to get kernel dump size"));
                return (-1);
        }

        if (dcp->dc_parsable)
                (void) snprintf(buf, sizeof (buf), "%llu", d);
        else
                zfs_nicenum(d, buf, sizeof (buf));

        if (dcp->dc_headers)
                (void) printf(gettext("Estimated dump size: "));
        (void) printf("%s\n", buf);
        return (0);
}

void
dconf_print(dumpconf_t *dcp, FILE *fp)
{
        u_longlong_t min;
        char *content;

        if (dcp->dc_cflags & DUMP_ALL)
                content = gettext("all");
        else if (dcp->dc_cflags & DUMP_CURPROC)
                content = gettext("kernel and current process");
        else
                content = gettext("kernel");

        (void) fprintf(fp, gettext("      Dump content: %s pages\n"), content);

        if (dcp->dc_device[0] != '\0') {
                (void) fprintf(fp, gettext("       Dump device: %s (%s)\n"),
                    dcp->dc_device, (dcp->dc_cflags & DUMP_EXCL) ?
                    gettext("dedicated") : gettext("swap"));
        } else {
                (void) fprintf(fp, gettext("       Dump device: none "
                    "(dumps disabled)\n"));
        }

        (void) fprintf(fp, gettext("Savecore directory: %s"), dcp->dc_savdir);

        if (minfree_read(dcp->dc_savdir, &min) == 0) {
                if (min < 1024 || (min % 1024) != 0)
                        (void) fprintf(fp, gettext(" (minfree = %lluKB)"), min);
                else
                        (void) fprintf(fp, gettext(" (minfree = %lluMB)"),
                            min / 1024);
        }

        (void) fprintf(fp, gettext("\n"));

        (void) fprintf(fp, gettext("  Savecore enabled: %s\n"),
            (dcp->dc_enable == DC_OFF) ? gettext("no") : gettext("yes"));
        (void) fprintf(fp, gettext("   Save compressed: %s\n"),
            (dcp->dc_csave == DC_UNCOMPRESSED) ? gettext("off") :
            gettext("on"));
}

int
dconf_str2device(dumpconf_t *dcp, char *buf)
{
        if (strcasecmp(buf, DC_STR_SWAP) == 0) {
                (void) strcpy(dcp->dc_device, DC_STR_SWAP);
                return (0);
        }

        if (strcasecmp(buf, DC_STR_NONE) == 0) {
                (void) strcpy(dcp->dc_device, DC_STR_NONE);
                return (0);
        }

        if (valid_abspath(buf)) {
                (void) strcpy(dcp->dc_device, buf);
                return (0);
        }

        return (-1);
}

int
dconf_str2savdir(dumpconf_t *dcp, char *buf)
{
        if (valid_abspath(buf)) {
                (void) strcpy(dcp->dc_savdir, buf);
                return (0);
        }

        return (-1);
}

int
dconf_str2content(dumpconf_t *dcp, char *buf)
{
        if (strcasecmp(buf, DC_STR_KERNEL) == 0) {
                dcp->dc_cflags = (dcp->dc_cflags & ~DUMP_CONTENT) | DUMP_KERNEL;
                return (0);
        }

        if (strcasecmp(buf, DC_STR_CURPROC) == 0) {
                dcp->dc_cflags = (dcp->dc_cflags & ~DUMP_CONTENT) |
                    DUMP_CURPROC;
                return (0);
        }

        if (strcasecmp(buf, DC_STR_ALL) == 0) {
                dcp->dc_cflags = (dcp->dc_cflags & ~DUMP_CONTENT) | DUMP_ALL;
                return (0);
        }

        warn(gettext("invalid dump content type -- %s\n"), buf);
        return (-1);
}

int
dconf_str2enable(dumpconf_t *dcp, char *buf)
{
        if (strcasecmp(buf, DC_STR_YES) == 0) {
                dcp->dc_enable = DC_ON;
                return (0);
        }

        if (strcasecmp(buf, DC_STR_NO) == 0) {
                dcp->dc_enable = DC_OFF;
                return (0);
        }

        warn(gettext("invalid enable value -- %s\n"), buf);
        return (-1);
}

int
dconf_str2csave(dumpconf_t *dcp, char *buf)
{
        if (strcasecmp(buf, DC_STR_ON) == 0) {
                dcp->dc_csave = DC_COMPRESSED;
                return (0);
        }

        if (strcasecmp(buf, DC_STR_OFF) == 0) {
                dcp->dc_csave = DC_UNCOMPRESSED;
                return (0);
        }

        warn(gettext("invalid save compressed value -- %s\n"), buf);
        return (-1);
}

static int
print_content(const dumpconf_t *dcp, FILE *fp)
{
        const char *content;

        if (dcp->dc_cflags & DUMP_ALL)
                content = DC_STR_ALL;
        else if (dcp->dc_cflags & DUMP_CURPROC)
                content = DC_STR_CURPROC;
        else
                content = DC_STR_KERNEL;

        return (fprintf(fp, "%s\n", content));
}

static int
print_device(const dumpconf_t *dcp, FILE *fp)
{
        return (fprintf(fp, "%s\n", (dcp->dc_device[0] != '\0') ?
            dcp->dc_device : DC_STR_SWAP));
}

static int
print_enable(const dumpconf_t *dcp, FILE *fp)
{
        return (fprintf(fp, "%s\n", (dcp->dc_enable == DC_OFF) ?
            DC_STR_NO : DC_STR_YES));
}

static int
print_csave(const dumpconf_t *dcp, FILE *fp)
{
        return (fprintf(fp, "%s\n", (dcp->dc_csave == DC_COMPRESSED) ?
            DC_STR_ON : DC_STR_OFF));
}

static int
print_savdir(const dumpconf_t *dcp, FILE *fp)
{
        return (fprintf(fp, "%s\n", dcp->dc_savdir));
}