/*
 * 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 2005 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <strings.h>
#include <fcntl.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#include <sys/fssnap_if.h>
#include <sys/filio.h>
#include <setjmp.h>
#include <stdarg.h>
#include <kstat.h>
#include <libintl.h>
#include <libdevinfo.h>
#include <sys/sysmacros.h>
#include <sys/fs/ufs_fs.h>
#include <sys/fs/ufs_snap.h>

#define SNAP_CTL_PATH   "/dev/" SNAP_CTL_NAME

#define MAX_SUFFIX      6       /* '.' + 4 chars of number + trailing '\0' */

#define POWEROF2(num)   (((num) & ((num) - 1)) == 0)

static int max_uniq = 9999;

void create_snap(int, char *, u_offset_t, uint_t, int, int);
void delete_snap(int);
void stats_snap(char *, char *);

int open_backpath(int, u_offset_t, char **, char **, int **);
u_offset_t spec_to_bytes(char *);
void gen_backing_store_path(char *basepath, int num, char **outpath);
void unlink_all(char *, int);
void close_all(char *, int, int *);
int open_multi_backfile(char *, int, int **, int);

void die_perror(char *);
void die_errno(int, char *, ...);
void die_create_error(int error);
void die_usage(void);
void die(char *, ...);
void warn_errno(int, char *,  ...);
void usage(void);

static char *subopts[] = {
#define BACKPATH        (0)
        "backing-store",
#define BACKPATH2       (1)
        "bs",
#define BACKPATH3       (2)
        "bf",
#define MAXSIZE         (3)
        "maxsize",
#define CHUNKSIZE       (4)
        "chunksize",
#define RAWFILE         (5)
        "raw",
#define UNLINK          (6)
        "unlink",
        NULL
};

static jmp_buf err_main;
static char *progname = NULL;
static int backout_snap_fd = -1;

extern void fssnap_show_status(char *mountpoint, char *opts, int labels,
    int brief); /* in ../../fssnapsup.c */

int
main(int argc, char *argv[])
{
        int c;
        char *suboptions = NULL;
        char *value;
        int longjmp_return;

        char *volatile mountpoint = NULL;
        int volatile mountfd = -1;
        char *volatile backpath = NULL;

        int volatile delete = 0;
        int volatile stats = 0;
        u_offset_t volatile maxsize = 0;
        uint_t volatile chunksize = 0;
        int volatile rawfile = 0;
        int volatile dounlink = 0;

        if ((progname = strrchr(argv[0], '/')) != NULL)
                ++progname;
        else
                progname = argv[0];

        if ((longjmp_return = setjmp(err_main)) != 0) {
                if (backout_snap_fd >= 0) {
                        mountfd = backout_snap_fd;
                        backout_snap_fd = -1; /* prevent infinite loop */
                        delete_snap(mountfd);
                }

                return (longjmp_return);
        }

        while ((c = getopt(argc, argv, "dio:")) != EOF) {
                switch (c) {
                case 'd':
                        ++delete;
                        break;

                case 'i':
                        ++stats;
                        break;

                case 'o':
                        suboptions = optarg;
                        break;

                default:
                        die_usage();
                }
        }

        /* if -i or -d are not specified then interpret the create options */
        if ((stats == 0) && (delete == 0) && (suboptions != NULL)) {
                while (*suboptions != '\0') {

                        switch ((getsubopt(&suboptions, subopts, &value))) {
                        case BACKPATH:
                        case BACKPATH2:
                        case BACKPATH3:
                                if (value == NULL)
                                        die_usage();
                                backpath = strdup(value);
                                if (backpath == NULL) {
                                        die_perror("strdup");
                                }
                                break;

                        case MAXSIZE:
                                maxsize = spec_to_bytes(value);
                                break;

                        case CHUNKSIZE:
                                chunksize = spec_to_bytes(value);
                                break;

                        case RAWFILE:
                                ++rawfile;
                                break;

                        case UNLINK:
                                ++dounlink;
                                break;

                        default:
                                die_usage();
                        }
                }
        }

        /* -d and -i can not be specified together or more than once each */
        if ((delete + stats) > 1)
                die_usage();

        /* If no mount point is specified then -i is the only valid option. */
        if ((optind >= argc) && (stats == 0))
                die_usage();

        /*
         * If anything but the mount point or device is specified at the end
         * it's an error.
         */
        if (optind != (argc - 1)) {
                if (!stats)
                        die_usage();
        } else {
                /* Otherwise, the last option is the mountpoint. */
                mountpoint = argv[optind];
                if ((mountfd = open(mountpoint, O_RDONLY)) < 0)
                        die_perror(mountpoint);
        }

        if (stats != 0) {
                stats_snap(mountpoint, suboptions);
        } else if (delete != 0) {
                delete_snap(mountfd);
        } else {
                /*
                 * backpath may be invalid upon return of create_snap call.
                 */
                create_snap(mountfd, backpath, maxsize, chunksize,
                    rawfile, dounlink);
        }

        return (0);
}

void
create_snap(int mountfd, char *backpath, u_offset_t maxsize, uint_t chunksize,
    int rawfile, int dounlink)
{
        struct fiosnapcreate_multi *enable;
        int backcount;
        int ctlfd;
        char *unlinkpath = NULL;
        di_devlink_handle_t hdl;
        int *fd_array;
        u_offset_t max_bf_size;
        int save_errno;

        /*
         * If chunksize is not a power of 2, the maximum size of a
         * backing store file might not be UFS_MAX_SNAPBACKFILESIZE,
         * since the size of the backing store files must be an
         * integral number of chunks (except for the last one).  So
         * calculate the actual maximum backing store file size.
         * (It would be nice if we could assume that the chunksize
         * was a power of 2, but we can't.)
         */

        if (chunksize != 0 && !POWEROF2(chunksize))
                max_bf_size = (UFS_MAX_SNAPBACKFILESIZE/chunksize) * chunksize;
        else
                max_bf_size = UFS_MAX_SNAPBACKFILESIZE;

        /*
         * open_backpath() only returns on success, and
         * can change the value of backpath when backpath
         * references a directory.
         */
        if (backpath == NULL)
                die(gettext("No backing store path specified.\n"));
        backcount = open_backpath(mountfd, max_bf_size, &backpath,
            &unlinkpath, &fd_array);

        /*
         * Only need backcount - 1 spaces for fd's since
         * fiosnapcreate_multi struct contains space for the
         * first one.
         */
        if ((enable = calloc(1, sizeof (struct fiosnapcreate_multi) +
            (backcount - 1) * sizeof (int))) == NULL)
                die(gettext("Insufficient memory.\n"));

        enable->backfilecount = backcount;
        bcopy(fd_array, &(enable->backfiledesc), backcount * sizeof (int));

        enable->rootfiledesc = mountfd;

        enable->maxsize = maxsize;
        enable->chunksize = chunksize;
        enable->backfilesize = max_bf_size;

        /*
         * enable.backfilename is advisory only.  So, we don't overflow
         * the buffer, but we don't give an error if the backpath does not
         * fit.  Instead, it is truncated, and the kstat shows all it can.
         */
        if (backpath != NULL) {
                if (dounlink)
                        (void) snprintf(enable->backfilename,
                            sizeof (enable->backfilename) - 1, "%s <UNLINKED>",
                            backpath);
                else
                        (void) strncpy(enable->backfilename, backpath,
                            sizeof (enable->backfilename) - 1);
                enable->backfilename[sizeof (enable->backfilename)-1] = '\0';
        }

        if ((ctlfd = open(SNAP_CTL_PATH, O_RDONLY | O_EXCL)) == -1) {
                unlink_all(unlinkpath, backcount);
                die_perror(SNAP_CTL_PATH);
        }

        if (ioctl(ctlfd, _FIOSNAPSHOTCREATE_MULTI, enable) == -1) {
                unlink_all(unlinkpath, backcount);
                if (enable->error != 0) {
                        die_create_error(enable->error);
                } else {
                        die_perror("ioctl");
                }
        }

        backout_snap_fd = mountfd;
        if (dounlink != 0)
                unlink_all(unlinkpath, backcount);

        if (close(ctlfd) != 0) {
                save_errno = errno;
                die_errno(save_errno, gettext("close of control file (%s)"),
                    SNAP_CTL_PATH);
        }

        close_all(unlinkpath, backcount, fd_array);

        if ((hdl = di_devlink_init("fssnap", DI_MAKE_LINK)) == NULL) {
                save_errno = errno;
                warn_errno(save_errno,
                    gettext("/dev/%s/%d may not be immediately available\n"),
                    (rawfile) ? SNAP_CHAR_NAME : SNAP_BLOCK_NAME,
                    enable->snapshotnumber);
        } else {
                (void) di_devlink_fini(&hdl);
        }

        /* intentionally not internationalized */
        printf("/dev/%s/%d\n", (rawfile) ? SNAP_CHAR_NAME : SNAP_BLOCK_NAME,
            enable->snapshotnumber);

        free(enable);
}

void
delete_snap(int mountfd)
{
        struct fiosnapdelete disable;
        int ctlfd;
        int save_errno;

        bzero(&disable, sizeof (disable));
        if ((ctlfd = open(SNAP_CTL_PATH, O_RDONLY | O_EXCL)) == -1)
                die_perror(SNAP_CTL_PATH);

        disable.rootfiledesc = mountfd;
        if (ioctl(ctlfd, _FIOSNAPSHOTDELETE, &disable) == -1) {
                if (disable.error) {
                        die(gettext("error %d"), disable.error);
                } else {
                        die_perror("ioctl");
                }
        }

        if (close(ctlfd) != 0) {
                save_errno = errno;
                die_errno(save_errno, gettext("close of control file (%s)"),
                    SNAP_CTL_PATH);
        }

        printf(gettext("Deleted snapshot %d.\n"), disable.snapshotnumber);
}

void
stats_snap(char *mountpath, char *opts)
{
        fssnap_show_status(mountpath, opts, ((opts != NULL) ? 0 : 1), 0);
}

/*
 * Open as many backing files as necessary for this snapshot.
 * There will be one backing file for each max_bf_size
 * number of bytes in the file system being snapped.
 * The array of file descriptors for the backing files is returned in
 * fd_array.  The number of backing files is the return value of the
 * function.  The name of the first backing file is returned in
 * unlinkpath.  The subsequent backing files are assumed to have the
 * same name as the first, but with suffixes, .2, .3, etc.
 */
int
open_backpath(int mountfd, u_offset_t max_bf_size, char **path,
    char **unlinkpath, int **fd_array)
{
        struct stat st;
        struct statvfs vfs;
        int fd, uniq, len;
        int ret_errno, i, num_back_files;
        offset_t fssize, backfilesize;
        char *locpath = NULL;
        int save_errno;

        *unlinkpath = NULL;

        /* determine size of the file system to be snapped */
        if (fstatvfs(mountfd, &vfs) == -1)
                die_perror("statvfs");

        fssize = vfs.f_blocks * vfs.f_frsize;
        num_back_files = howmany(fssize, max_bf_size);

        if (stat(*path, &st) < 0) {
                /*
                 * Since we set the file_exists_is_fatal argument to 1,
                 * if we return at all, it will be with all the backing
                 * files successfully created and opened.
                 */
                (void) open_multi_backfile(*path, num_back_files, fd_array, 1);
                *unlinkpath = strdup(*path);
                if (unlinkpath == NULL)
                        die_perror("strdup");
        } else if (S_ISDIR(st.st_mode)) {
                char temppath[MAXPATHLEN];

                /* remove a trailing slash from the name */
                len = strlen(*path) - 1;
                if ((*path)[len] == '/')
                        (*path)[len] = '\0';

                /* find a unique name */
                for (uniq = 0; uniq <= max_uniq; uniq++) {
                        /* cannot use tempnam, since TMPDIR overrides path */
                        (void) snprintf(temppath, MAXPATHLEN, "%s/snapshot%d",
                            *path, uniq);
                        ret_errno = open_multi_backfile(temppath,
                            num_back_files, fd_array, 0);
                        if (ret_errno == 0)
                                break;
                }
                if (uniq > max_uniq) {
                        die(gettext("Could not find unique name in %s"), *path);
                }
                *unlinkpath = strdup(temppath);
                free(*path);
                *path = *unlinkpath;
        } else if (S_ISREG(st.st_mode)) {
                die(gettext("%s already exists."), *path);
        } else {
                die(gettext("%s: must be either the name of a file to create "
                    "or a directory."), *path);
        }

        /*
         * write a block to the end to bump up the file size and ensure the
         * entire range needed can be written to.
         */
        for (i = 0; i < num_back_files; i++) {
                fd = (*fd_array)[i];
                if (i == num_back_files - 1 && fssize % max_bf_size != 0)
                        backfilesize = fssize % max_bf_size;
                else
                        backfilesize = max_bf_size;
                if (llseek(fd, backfilesize - 1, SEEK_SET) == -1) {
                        unlink_all(*unlinkpath, num_back_files);
                        die_perror("llseek");
                }

                if (write(fd, "0", 1) == -1) {
                        save_errno = errno;
                        unlink_all(*unlinkpath, num_back_files);
                        if (save_errno == EFBIG)
                                die(gettext("File system %s "
                                    "does not support large files.\n"), *path);
                        else
                                die_perror("write");
                }
        }
        return (num_back_files);
}

u_offset_t
spec_to_bytes(char *spec)
{
        u_offset_t base;

        base = strtoull(spec, NULL, 10);
        if ((base == 0LL) && (spec[0] != '0'))
                die(gettext("Numeric option value expected"));

        spec += strspn(spec, "0123456789");

        if ((spec == NULL) || strlen(spec) != 1)
                die(gettext("Only one of b, k, m, or g may be used"));

        switch (spec[0]) {
        case 'B':
        case 'b':
                base *= 512;
                break;
        case 'K':
        case 'k':
                base *= 1024;
                break;
        case 'M':
        case 'm':
                base *= 1024 * 1024;
                break;
        case 'G':
        case 'g':
                base *= 1024 * 1024 * 1024;
                break;
        default:
                die(gettext("Must specify one of b, k, m, or g on size"));
        }

        return (base);
}

/*
 * Make sure that the first call to gen_backing_store() in a loop
 * starts with a null pointer in the outpath argument
 * and continues to pass in that same argument until
 * the loop is complete, at which point the string
 * pointed to by that argument must be freed by the caller.
 */
void
gen_backing_store_path(char *basepath, int num, char **outpath)
{
        if (*outpath == NULL) {
                *outpath = malloc(strlen(basepath) + MAX_SUFFIX);
                if (*outpath == NULL)
                        die_perror("malloc");
        }

        /*
         * Security note:  We use strcpy here, instead of the safer
         * strncpy, because the string pointed to by outpath has
         * been generated by THIS code, above.  Hence it is impossible
         * for the strcpy to overrun the buffer.
         */
        if (num == 1)
                (void) strcpy(*outpath, basepath);
        else
                (void) sprintf(*outpath, "%s.%d", basepath, num);
}

void
unlink_all(char *unlinkpath, int count)
{
        char    *bspath = NULL;
        int     i;
        int     save_errno;

        for (i = 1; i <= count; i++) {
                /*
                 * Make sure that the first call to gen_backing_store()
                 * starts with a null pointer in the third argument
                 * and continues to pass in that same argument until
                 * the loop is complete, at which point the string
                 * pointed to by that argument must be freed.
                 */
                gen_backing_store_path(unlinkpath, i, &bspath);
                if (unlink(bspath) < 0) {
                        save_errno = errno;
                        warn_errno(save_errno,
                            gettext("could not unlink %s"), bspath);
                }
        }
        free(bspath);
}

void
close_all(char *closepath, int count, int *fd_array)
{
        char    *bspath = NULL;
        int     i;
        int     save_errno;

        for (i = 1; i <= count; i++) {
                if (close(fd_array[i - 1]) != 0) {
                        save_errno = errno;
                        /*
                         * Make sure that the first call to gen_backing_store()
                         * starts with a null pointer in the third argument
                         * and continues to pass in that same argument until
                         * the loop is complete, at which point the string
                         * pointed to by that argument must be freed.
                         */
                        gen_backing_store_path(closepath, i, &bspath);
                        die_errno(save_errno, gettext(
                            "close of backing-store (%s)"), bspath);
                }
        }
        if (bspath != NULL)
                free(bspath);
}

/*
 * Create "count" files starting with name backpath ("backpath",
 * "backpath".2, "backpath".3, etc.  When this function returns,
 * either all of the files will exist and be opened (and their
 * file descriptors will be in fd_array), or NONE of will exist
 * (if they had to be created) and opened (that is, if we created a file,
 * and then failed to create a later file, the earlier files will
 * be closed and unlinked.)
 *
 * If file_exists_is_fatal is set, it is a fatal error (resulting in
 * an error message and termination) if any of the backing files to
 * be created already exists.  Otherwise, if one of the backing
 * files already exists, we close and unlink all the files we already
 * created, and return an error to the caller, but we don't print
 * an error or terminate.
 *
 * If there is any failure other than EEXIST when attempting to
 * create the file, the routine prints an error and terminates the
 * program, regardless of the setting of file_exists_is_fatal.
 */
int
open_multi_backfile(char *backpath, int count, int **fd_array,
    int file_exists_is_fatal)
{
        char    *wpath = NULL;          /* working path */
        int     i, j, fd;
        struct stat st;
        int     stat_succeeded = 0;
        int     save_errno;

        *fd_array = (int *)malloc(count * sizeof (int));
        if (*fd_array == NULL)
                die_perror("malloc");

        for (i = 0; i < count; i++) {
                /*
                 * Make sure that the first call to gen_backing_store()
                 * starts with a null pointer in the third argument
                 * and continues to pass in that same argument until
                 * the loop is complete, at which point the string
                 * pointed to by that argument must be freed.
                 */
                gen_backing_store_path(backpath, i + 1, &wpath);
                if (stat(wpath, &st) == 0)
                        stat_succeeded = 1;
                else
                        fd = open(wpath, O_RDWR | O_CREAT | O_EXCL, 0600);
                if (stat_succeeded || fd < 0) {
                        if (i > 0) {
                                for (j = 0; j < i - 1; j++)
                                        (void) close((*fd_array)[j]);
                                /*
                                 * unlink_all's second argument is the number
                                 * of files to be removed, NOT the offset
                                 * into the array of fd's of the last
                                 * successfully created file.
                                 */
                                unlink_all(backpath, i);
                        }
                        if (stat_succeeded || errno == EEXIST) {
                                if (file_exists_is_fatal)
                                        die(gettext("%s exists, please specify"
                                            " a nonexistent backing store."),
                                            wpath);
                                else
                                        return (1);
                        } else {
                                        save_errno = errno;
                                        die_errno(save_errno,
                                            gettext("Could not create"
                                            " backing file %s"), wpath);
                        }
                }
                (*fd_array)[i] = fd;
        }
        if (wpath != NULL)
                free(wpath);
        return (0);
}

void
die_perror(char *string)
{
        int en = errno;
        char *errstr;

        if (string == NULL) {
                string = gettext("Fatal");
        }
        errstr = strerror(en);
        if (errstr == NULL) {
                errstr = gettext("Unknown error");
        }

        fprintf(stderr, gettext("%s: %s: error %d: %s\n"),
            progname, string, en, errstr);

        longjmp(err_main, 2);
}

void
die_usage(void)
{
        usage();

        longjmp(err_main, 1);
}

void
warn_errno(int en, char *fmt, ...)
{
        va_list ap;
        char *errstr;

        errstr = strerror(en);
        if (errstr == NULL) {
                errstr = gettext("Unknown error");
        }

        va_start(ap, fmt);
        fprintf(stderr, gettext("%s: Warning: "), progname);
        vfprintf(stderr, fmt, ap);
        fprintf(stderr, ": %s\n", errstr);
        va_end(ap);
}

void
die_errno(int en, char *fmt, ...)
{
        va_list ap;
        char *errstr;

        errstr = strerror(en);
        if (errstr == NULL) {
                errstr = gettext("Unknown error");
        }

        va_start(ap, fmt);
        fprintf(stderr, gettext("%s: Fatal: "), progname);
        vfprintf(stderr, fmt, ap);
        fprintf(stderr, ": %s\n", errstr);
        va_end(ap);

        longjmp(err_main, 2);
}

void
die_create_error(int error)
{
        fprintf(stderr, gettext("snapshot error: "));
        switch (error) {
        case FIOCOW_EREADONLY:
                fprintf(stderr, gettext("Read only file system\n"));
                break;
        case FIOCOW_EBUSY:
                fprintf(stderr, gettext("Snapshot already enabled\n"));
                break;
        case FIOCOW_EULOCK:
                fprintf(stderr, gettext("File system is locked\n"));
                break;
        case FIOCOW_EWLOCK:
                fprintf(stderr,
                    gettext("File system could not be write locked\n"));
                break;
        case FIOCOW_EFLUSH:
                fprintf(stderr, gettext("File system could not be flushed\n"));
                break;
        case FIOCOW_ECLEAN:
                fprintf(stderr, gettext("File system may not be stable\n"));
                break;
        case FIOCOW_ENOULOCK:
                fprintf(stderr, gettext("File system could not be unlocked\n"));
                break;
        case FIOCOW_ECHUNKSZ:
                fprintf(stderr, gettext("Chunk size must be a multiple of the "
                    "fragment size\n"));
                break;
        case FIOCOW_ECREATE:
                fprintf(stderr, gettext("Could not allocate or create "
                    "a new snapshot\n"));
                break;
        case FIOCOW_EBITMAP:
                fprintf(stderr,
                    gettext("Error scanning file system bitmaps\n"));
                break;
        case FIOCOW_EBACKFILE:
                fprintf(stderr, gettext("Invalid backing file path\n"));
                break;
        default:
                fprintf(stderr, gettext("Unknown create error\n"));
                break;
        }

        longjmp(err_main, 2);
}

void
die(char *fmt, ...)
{
        va_list ap;

        va_start(ap, fmt);
        fprintf(stderr, gettext("%s: Fatal: "), progname);
        vfprintf(stderr, fmt, ap);
        fprintf(stderr, "\n");
        va_end(ap);

        longjmp(err_main, 2);
}

void
usage(void)
{
        int  i;
        char *use_str[] = {
                "   %s [-F ufs] [-V] -o backing-store=path,[special_options] "
                    "/mount/point\n",
                "   %s -d [-F ufs] [-V] /mount/point | dev\n",
                "   %s -i [-F ufS] [-V] [-o special-options] /mount/point "
                    "| dev\n",
                NULL
        };
        fprintf(stderr, gettext("Usage:\n"));
        for (i = 0; use_str[i] != NULL; i++)
                fprintf(stderr, gettext(use_str[i]), progname);
}