/*
 * Copyright (c) 2008 The DragonFly Project.  All rights reserved.
 *
 * This code is derived from software contributed to The DragonFly Project
 * by Matthew Dillon <dillon@backplane.com>
 * 
 * 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.
 * 3. Neither the name of The DragonFly Project nor the names of its
 *    contributors may be used to endorse or promote products derived
 *    from this software without specific, prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * ``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
 * COPYRIGHT HOLDERS OR CONTRIBUTORS 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.
 *
 * $DragonFly: src/sbin/hammer/cmd_cleanup.c,v 1.6 2008/10/07 22:28:41 thomas Exp $
 */
/*
 * Clean up a specific HAMMER filesystem or all HAMMER filesystems.
 *
 * Each filesystem is expected to have a <mount>/snapshots directory.
 * No cleanup will be performed on any filesystem that does not.  If
 * no filesystems are specified the 'df' program is run and any HAMMER
 * or null-mounted hammer PFS's are extracted.
 *
 * The snapshots directory may contain a config file called 'config'.  If
 * no config file is present one will be created with the following
 * defaults:
 *
 *	snapshots 1d 60d	(0d 0d for /tmp, /var/tmp, /usr/obj)
 *	prune     1d 5m
 *	reblock   1d 5m
 *	recopy    30d 5m
 *
 * All hammer commands create and maintain cycle files in the snapshots
 * directory.
 */

#include "hammer.h"

struct didpfs {
	struct didpfs *next;
	uuid_t		uuid;
};

static void do_cleanup(const char *path);
static int strtosecs(char *ptr);
static const char *dividing_slash(const char *path);
static int check_period(const char *snapshots_path, const char *cmd, int arg1,
			time_t *savep);
static void save_period(const char *snapshots_path, const char *cmd,
			time_t savet);
static int check_softlinks(const char *snapshots_path);
static void cleanup_softlinks(const char *path, const char *snapshots_path,
			int arg2, char *arg3);
static int check_expired(const char *fpath, int arg2);

static int cleanup_snapshots(const char *path, const char *snapshots_path,
			      int arg1, int arg2);
static int cleanup_prune(const char *path, const char *snapshots_path,
			      int arg1, int arg2, int snapshots_disabled);
static int cleanup_reblock(const char *path, const char *snapshots_path,
			      int arg1, int arg2);
static int cleanup_recopy(const char *path, const char *snapshots_path,
			      int arg1, int arg2);

static void runcmd(int *resp, const char *ctl, ...);

#define WS	" \t\r\n"

struct didpfs *FirstPFS;

void
hammer_cmd_cleanup(char **av, int ac)
{
	FILE *fp;
	char *fs, *ptr, *path;
	char buf[256];

	tzset();
	if (ac == 0) {
		fp = popen("mount -t hammer,null", "r");
		if (fp == NULL)
			errx(1, "hammer cleanup: 'mount' failed");
		while (fgets(buf, sizeof(buf), fp) != NULL) {
			fs = strtok(buf, WS);
			if (fs == NULL)
				continue;
			ptr = strtok(NULL, WS);
			if (ptr == NULL)
				continue;
			path = strtok(NULL, WS);
			if (path == NULL)
				continue;
			ptr = strtok(NULL, WS);
			if (ptr == NULL)
				continue;
			if ((strncmp(ptr, "(hammer,", 8) == 0) ||
			    ((strncmp(ptr, "(null,", 6) == 0) &&
			     (strncmp(fs, "/pfs", 4) == 0)))
				do_cleanup(path);
		}
		fclose(fp);
	} else {
		while (ac) {
			do_cleanup(*av);
			--ac;
			++av;
		}
	}
}

static
void
do_cleanup(const char *path)
{
	struct hammer_ioc_pseudofs_rw pfs;
	union hammer_ioc_mrecord_any mrec_tmp;
	char *snapshots_path;
	char *config_path;
	struct stat st;
	char *cmd;
	char *ptr;
	int arg1;
	int arg2;
	char *arg3;
	time_t savet;
	char buf[256];
	FILE *fp;
	struct didpfs *didpfs;
	int snapshots_disabled = 0;
	int prune_warning = 0;
	int fd;
	int r;

	bzero(&pfs, sizeof(pfs));
	bzero(&mrec_tmp, sizeof(mrec_tmp));
	pfs.ondisk = &mrec_tmp.pfs.pfsd;
	pfs.bytes = sizeof(mrec_tmp.pfs.pfsd);
	pfs.pfs_id = -1;

	printf("cleanup %-20s -", path);
	fd = open(path, O_RDONLY);
	if (fd < 0) {
		printf(" unable to access directory: %s\n", strerror(errno));
		return;
	}
	if (ioctl(fd, HAMMERIOC_GET_PSEUDOFS, &pfs) != 0) {
		printf(" not a HAMMER filesystem: %s\n", strerror(errno));
		return;
	}
	close(fd);
	if (pfs.version != HAMMER_IOC_PSEUDOFS_VERSION) {
		printf(" unrecognized HAMMER version\n");
		return;
	}

	/*
	 * Make sure we have not already handled this PFS.  Several nullfs
	 * mounts might alias the same PFS.
	 */
	for (didpfs = FirstPFS; didpfs; didpfs = didpfs->next) {
		if (bcmp(&didpfs->uuid, &mrec_tmp.pfs.pfsd.unique_uuid, sizeof(uuid_t)) == 0) {
			printf(" PFS #%d already handled\n", pfs.pfs_id);
			return;
		}
	}
	didpfs = malloc(sizeof(*didpfs));
	didpfs->next = FirstPFS;
	FirstPFS = didpfs;
	didpfs->uuid = mrec_tmp.pfs.pfsd.unique_uuid;

	/*
	 * Figure out where the snapshot directory is.
	 */
	if (mrec_tmp.pfs.pfsd.snapshots[0] == '/') {
		asprintf(&snapshots_path, "%s", mrec_tmp.pfs.pfsd.snapshots);
	} else if (mrec_tmp.pfs.pfsd.snapshots[0]) {
		printf(" WARNING: pfs-slave's snapshots dir is not absolute\n");
		return;
	} else if (mrec_tmp.pfs.pfsd.mirror_flags & HAMMER_PFSD_SLAVE) {
		printf(" WARNING: must configure snapshot dir for PFS slave\n");
		printf("\tWe suggest <fs>/var/slaves/<name> where "
		       "<fs> is the base HAMMER fs\n");
		printf("\tcontaining the slave\n");
		return;
	} else {
		asprintf(&snapshots_path,
			 "%s%ssnapshots", path, dividing_slash(path));
	}

	/*
	 * Create a snapshot directory if necessary, and a config file if
	 * necessary.
	 */
	if (stat(snapshots_path, &st) < 0) {
		if (mkdir(snapshots_path, 0755) != 0) {
			free(snapshots_path);
			printf(" unable to create snapshot dir \"%s\": %s\n",
				snapshots_path, strerror(errno));
			return;
		}
	}
	asprintf(&config_path, "%s/config", snapshots_path);
	if ((fp = fopen(config_path, "r")) == NULL) {
		fp = fopen(config_path, "w");
		if (fp == NULL) {
			printf(" cannot create %s: %s\n",
				config_path, strerror(errno));
			return;
		}
		if (strcmp(path, "/tmp") == 0 ||
		    strcmp(path, "/var/tmp") == 0 ||
		    strcmp(path, "/usr/obj") == 0) {
			fprintf(fp, "snapshots 0d 0d\n");
		} else {
			fprintf(fp, "snapshots 1d 60d\n");
		}
		fprintf(fp, 
			"prune     1d 5m\n"
			"reblock   1d 5m\n"
			"recopy    30d 10m\n");
		fclose(fp);
		fp = fopen(config_path, "r");
	}
	if (fp == NULL) {
		printf(" cannot access %s: %s\n",
		       config_path, strerror(errno));
		return;
	}

	printf(" handle PFS #%d using %s\n", pfs.pfs_id, snapshots_path);

	/*
	 * Process the config file
	 */
	while (fgets(buf, sizeof(buf), fp) != NULL) {
		cmd = strtok(buf, WS);
		arg1 = 0;
		arg2 = 0;
		arg3 = NULL;
		if ((ptr = strtok(NULL, WS)) != NULL) {
			arg1 = strtosecs(ptr);
			if ((ptr = strtok(NULL, WS)) != NULL) {
				arg2 = strtosecs(ptr);
				arg3 = strtok(NULL, WS);
			}
		}

		printf("%20s - ", cmd);
		fflush(stdout);

		r = 1;
		if (strcmp(cmd, "snapshots") == 0) {
			if (arg1 == 0) {
				if (arg2 && check_softlinks(snapshots_path)) {
					printf("only removing old snapshots\n");
					prune_warning = 1;
					cleanup_softlinks(path, snapshots_path,
							  arg2, arg3);
				} else {
					printf("disabled\n");
					snapshots_disabled = 1;
				}
			} else
			if (check_period(snapshots_path, cmd, arg1, &savet)) {
				printf("run\n");
				cleanup_softlinks(path, snapshots_path,
						  arg2, arg3);
				r = cleanup_snapshots(path, snapshots_path,
						  arg1, arg2);
			} else {
				printf("skip\n");
			}
		} else if (arg1 == 0) {
			/*
			 * The commands following this check can't handle
			 * a period of 0, so call the feature disabled and
			 * ignore the directive.
			 */
			printf("disabled\n");
		} else if (strcmp(cmd, "prune") == 0) {
			if (check_period(snapshots_path, cmd, arg1, &savet)) {
				if (prune_warning) {
					printf("run - WARNING snapshot "
					       "softlinks present "
					       "but snapshots disabled\n");
				} else {
					printf("run\n");
				}
				r = cleanup_prune(path, snapshots_path,
					      arg1, arg2, snapshots_disabled);
			} else {
				printf("skip\n");
			}
		} else if (strcmp(cmd, "reblock") == 0) {
			if (check_period(snapshots_path, cmd, arg1, &savet)) {
				printf("run");
				fflush(stdout);
				if (VerboseOpt)
					printf("\n");
				r = cleanup_reblock(path, snapshots_path,
						arg1, arg2);
			} else {
				printf("skip\n");
			}
		} else if (strcmp(cmd, "recopy") == 0) {
			if (check_period(snapshots_path, cmd, arg1, &savet)) {
				printf("run");
				fflush(stdout);
				if (VerboseOpt)
					printf("\n");
				r = cleanup_recopy(path, snapshots_path,
					       arg1, arg2);
			} else {
				printf("skip\n");
			}
		} else {
			printf("unknown directive\n");
			r = 1;
		}
		if (r == 0)
			save_period(snapshots_path, cmd, savet);
	}
	fclose(fp);
	usleep(1000);
}

static
int
strtosecs(char *ptr)
{
	int val;

	val = strtol(ptr, &ptr, 0);
	switch(*ptr) {
	case 'd':
		val *= 24;
		/* fall through */
	case 'h':
		val *= 60;
		/* fall through */
	case 'm':
		val *= 60;
		/* fall through */
	case 's':
		break;
	default:
		errx(1, "illegal suffix converting %s\n", ptr);
		break;
	}
	return(val);
}

static const char *
dividing_slash(const char *path)
{
	int len = strlen(path);
	if (len && path[len-1] == '/')
		return("");
	else
		return("/");
}

/*
 * Check whether the desired period has elapsed since the last successful
 * run.  The run may take a while and cross a boundary so we remember the
 * current time_t so we can save it later on.
 *
 * Periods in minutes, hours, or days are assumed to have been crossed
 * if the local time crosses a minute, hour, or day boundary regardless
 * of how close the last operation actually was.
 */
static int
check_period(const char *snapshots_path, const char *cmd, int arg1,
	time_t *savep)
{
	char *check_path;
	struct tm tp1;
	struct tm tp2;
	FILE *fp;
	time_t baset, lastt;
	char buf[256];

	time(savep);
	localtime_r(savep, &tp1);

	/*
	 * Retrieve the start time of the last successful operation.
	 */
	asprintf(&check_path, "%s/.%s.period", snapshots_path, cmd);
	fp = fopen(check_path, "r");
	free(check_path);
	if (fp == NULL)
		return(1);
	if (fgets(buf, sizeof(buf), fp) == NULL) {
		fclose(fp);
		return(1);
	}
	fclose(fp);

	lastt = strtol(buf, NULL, 0);
	localtime_r(&lastt, &tp2);

	/*
	 * Normalize the times.  e.g. if asked to do something on a 1-day
	 * interval the operation will be performed as soon as the day
	 * turns over relative to the previous operation, even if the previous
	 * operation ran a few seconds ago just before midnight.
	 */
	if (arg1 % 60 == 0) {
		tp1.tm_sec = 0;
		tp2.tm_sec = 0;
	}
	if (arg1 % (60 * 60) == 0) {
		tp1.tm_min = 0;
		tp2.tm_min = 0;
	}
	if (arg1 % (24 * 60 * 60) == 0) {
		tp1.tm_hour = 0;
		tp2.tm_hour = 0;
	}

	baset = mktime(&tp1);
	lastt = mktime(&tp2);

#if 0
	printf("%lld vs %lld\n", (long long)(baset - lastt), (long long)arg1);
#endif

	if ((int)(baset - lastt) >= arg1)
		return(1);
	return(0);
}

/*
 * Store the start time of the last successful operation.
 */
static void
save_period(const char *snapshots_path, const char *cmd,
			time_t savet)
{
	char *ocheck_path;
	char *ncheck_path;
	FILE *fp;

	asprintf(&ocheck_path, "%s/.%s.period", snapshots_path, cmd);
	asprintf(&ncheck_path, "%s/.%s.period.new", snapshots_path, cmd);
	fp = fopen(ncheck_path, "w");
	fprintf(fp, "0x%08llx\n", (long long)savet);
	if (fclose(fp) == 0)
		rename(ncheck_path, ocheck_path);
	remove(ncheck_path);
}

/*
 * Simply count the number of softlinks in the snapshots dir
 */
static int
check_softlinks(const char *snapshots_path)
{
	struct dirent *den;
	struct stat st;
	DIR *dir;
	char *fpath;
	int res = 0;

	if ((dir = opendir(snapshots_path)) != NULL) {
		while ((den = readdir(dir)) != NULL) {
			if (den->d_name[0] == '.')
				continue;
			asprintf(&fpath, "%s/%s", snapshots_path, den->d_name);
			if (lstat(fpath, &st) == 0 && S_ISLNK(st.st_mode))
				++res;
			free(fpath);
		}
		closedir(dir);
	}
	return(res);
}

/*
 * Clean up expired softlinks in the snapshots dir
 */
static void
cleanup_softlinks(const char *path __unused, const char *snapshots_path,
		  int arg2, char *arg3)
{
	struct dirent *den;
	struct stat st;
	DIR *dir;
	char *fpath;
	int anylink = 0;

	if (arg3 != NULL && strstr(arg3, "any") != NULL)
		anylink = 1;

	if ((dir = opendir(snapshots_path)) != NULL) {
		while ((den = readdir(dir)) != NULL) {
			if (den->d_name[0] == '.')
				continue;
			asprintf(&fpath, "%s/%s", snapshots_path, den->d_name);
			if (lstat(fpath, &st) == 0 && S_ISLNK(st.st_mode) &&
			    (anylink || strncmp(den->d_name, "snap-", 5) == 0)
			) {
				if (check_expired(den->d_name, arg2)) {
					if (VerboseOpt) {
						printf("    expire %s\n",
							fpath);
					}
					remove(fpath);
				}
			}
			free(fpath);
		}
		closedir(dir);
	}
}

/*
 * Take a softlink path in the form snap-yyyymmdd-hhmm and the
 * expiration in seconds (arg2) and return non-zero if the softlink
 * has expired.
 */
static int
check_expired(const char *fpath, int arg2)
{
	struct tm tm;
	time_t t;
	int year;
	int month;
	int day = 0;
	int hour = 0;
	int minute = 0;
	int r;

	while (*fpath && *fpath != '-' && *fpath != '.')
		++fpath;
	if (*fpath)
		++fpath;

	r = sscanf(fpath, "%4d%2d%2d-%2d%2d",
		   &year, &month, &day, &hour, &minute);

	if (r >= 3) {
		bzero(&tm, sizeof(tm));
		tm.tm_isdst = -1;
		tm.tm_min = minute;
		tm.tm_hour = hour;
		tm.tm_mday = day;
		tm.tm_mon = month - 1;
		tm.tm_year = year - 1900;
		t = mktime(&tm);
		if (t == (time_t)-1)
			return(0);
		t = time(NULL) - t;
		if ((int)t > arg2)
			return(1);
	}
	return(0);
}

/*
 * Issue a snapshot.
 */
static int
cleanup_snapshots(const char *path __unused, const char *snapshots_path,
		  int arg1 __unused, int arg2 __unused)
{
	int r;

	runcmd(&r, "hammer snapshot %s %s", path, snapshots_path);
	return(r);
}

static int
cleanup_prune(const char *path __unused, const char *snapshots_path,
		  int arg1 __unused, int arg2, int snapshots_disabled)
{
	/*
	 * If snapshots have been disabled run prune-everything instead
	 * of prune.
	 */
	if (snapshots_disabled && arg2) {
		runcmd(NULL, "hammer -c %s/.prune.cycle -t %d prune-everything %s",
			snapshots_path, arg2, path);
	} else if (snapshots_disabled) {
		runcmd(NULL, "hammer prune-everything %s", path);
	} else if (arg2) {
		runcmd(NULL, "hammer -c %s/.prune.cycle -t %d prune %s",
			snapshots_path, arg2, snapshots_path);
	} else {
		runcmd(NULL, "hammer prune %s", snapshots_path);
	}
	return(0);
}

static int
cleanup_reblock(const char *path, const char *snapshots_path,
		  int arg1 __unused, int arg2)
{
	if (VerboseOpt == 0) {
		printf(".");
		fflush(stdout);
	}
	runcmd(NULL,
	       "hammer -c %s/.reblock-1.cycle -t %d reblock-btree %s 95",
	       snapshots_path, arg2, path);
	if (VerboseOpt == 0) {
		printf(".");
		fflush(stdout);
	}
	runcmd(NULL,
	       "hammer -c %s/.reblock-2.cycle -t %d reblock-inodes %s 95",
	       snapshots_path, arg2, path);
	if (VerboseOpt == 0) {
		printf(".");
		fflush(stdout);
	}
	runcmd(NULL,
	       "hammer -c %s/.reblock-3.cycle -t %d reblock-data %s 95",
	       snapshots_path, arg2, path);
	if (VerboseOpt == 0)
		printf("\n");
	return(0);
}

static int
cleanup_recopy(const char *path, const char *snapshots_path,
		  int arg1 __unused, int arg2)
{
	if (VerboseOpt == 0) {
		printf(".");
		fflush(stdout);
	}
	runcmd(NULL,
	       "hammer -c %s/.recopy-1.cycle -t %d reblock-btree %s",
	       snapshots_path, arg2, path);
	if (VerboseOpt == 0) {
		printf(".");
		fflush(stdout);
	}
	runcmd(NULL,
	       "hammer -c %s/.recopy-2.cycle -t %d reblock-inodes %s",
	       snapshots_path, arg2, path);
	if (VerboseOpt == 0) {
		printf(".");
		fflush(stdout);
	}
	runcmd(NULL,
	       "hammer -c %s/.recopy-3.cycle -t %d reblock-data %s",
	       snapshots_path, arg2, path);
	if (VerboseOpt == 0)
		printf("\n");
	return(0);
}

static
void
runcmd(int *resp, const char *ctl, ...)
{
	va_list va;
	char *cmd;
	char *arg;
	char **av;
	int n;
	int nmax;
	int res;
	pid_t pid;

	/*
	 * Generate the command
	 */
	va_start(va, ctl);
	vasprintf(&cmd, ctl, va);
	va_end(va);
	if (VerboseOpt)
		printf("    %s\n", cmd);

	/*
	 * Break us down into arguments.  We do not just use system() here
	 * because it blocks SIGINT and friends.
	 */
	n = 0;
	nmax = 16;
	av = malloc(sizeof(char *) * nmax);

	for (arg = strtok(cmd, WS); arg; arg = strtok(NULL, WS)) {
		if (n == nmax - 1) {
			nmax += 16;
			av = realloc(av, sizeof(char *) * nmax);
		}
		av[n++] = arg;
	}
	av[n++] = NULL;

	/*
	 * Run the command.
	 */
	if ((pid = fork()) == 0) {
		if (VerboseOpt < 2) {
			int fd = open("/dev/null", O_RDWR);
			dup2(fd, 1);
			close(fd);
		}
		execvp(av[0], av);
		_exit(127);
	} else if (pid < 0) {
		res = 127;
	} else {
		int status;
		while (waitpid(pid, &status, 0) != pid)
			;
		res = WEXITSTATUS(status);
	}

	free(cmd);
	free(av);
	if (resp)
		*resp = res;
}