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rcsid[] and sccsid[] and copyright[] are essentially unmaintained (and
unmaintainable).  these days, people use source.  these id's do not provide
any benefit, and do hurt the small install media
(the 33,000 line diff is essentially mechanical)
ok with the idea millert, ok dms

/*	$OpenBSD: filesys.c,v 1.11 2009/10/27 23:59:42 deraadt Exp $	*/

/*
 * Copyright (c) 1983 Regents of the University of California.
 * 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.
 * 3. Neither the name of the University 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 REGENTS 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 REGENTS 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.
 */

#include "defs.h"

/*
 * This file contains functions dealing with getting info
 * about mounted filesystems.
 */


jmp_buf env;

/*
 * Given a pathname, find the fullest component that exists.
 * If statbuf is not NULL, set it to point at our stat buffer.
 */
char *
find_file(char *pathname, struct stat *statbuf, int *isvalid)
{
	static char last_pathname[MAXPATHLEN];
	static char file[MAXPATHLEN + 3];
	static struct stat filestat;
	char *p;

	/*
	 * Mark the statbuf as invalid to start with.
	 */
	*isvalid = 0;

	/*
	 * If this is the same pathname as the last time, and
	 * the file buffer is valid and we're doing the same stat()
	 * or lstat(), then set statbuf to the last filestat and 
	 * return the last file we found.
	 */
	if (strcmp(pathname, last_pathname) == 0 && file[0]) {
		if (statbuf)
			statbuf = &filestat;
		if (strcmp(pathname, file) == 0)
			*isvalid = 1;
		return(file);
	}

	if (strlen(pathname) > sizeof(file) + 3) {
		error("%s: Name to large for buffer.", pathname);
	        return(NULL);
	}

	/*
	 * Save for next time
	 */
	(void) strlcpy(last_pathname, pathname, sizeof(last_pathname));

	if (*pathname == '/')
	        (void) strlcpy(file, pathname, sizeof(file));
	else {
		/*
		 * Ensure we have a directory (".") in our path
		 * so we have something to stat in case the file
		 * does not exist.
		 */
	        (void) strlcpy(file, "./", sizeof(file));
		(void) strlcat(file, pathname, sizeof(file));
	}

	while (lstat(file, &filestat) != 0) {
		/*
		 * Trim the last part of the pathname to try next level up
		 */
		if (errno == ENOENT) {
			/*
			 * Trim file name to get directory name.
			 * Normally we want to change /dir1/dir2/file
			 * into "/dir1/dir2/."
			 */
			if ((p = (char *) strrchr(file, '/')) != NULL) {
				if (strcmp(p, "/.") == 0) {
					*p = CNULL;
				} else {
					*++p = '.';
					*++p = CNULL;
				}
			} else {
				/*
				 * Couldn't find anything, so give up.
				 */
				debugmsg(DM_MISC, "Cannot find dir of `%s'",
					 pathname);
				return(NULL);
			}
			continue;
		} else {
			error("%s: lstat failed: %s", pathname, SYSERR);
			return(NULL);
		}
	}

	if (statbuf)
		bcopy((char *) &filestat, (char *) statbuf, sizeof(filestat));

	/*
	 * Trim the "/." that we added.
	 */
	p = &file[strlen(file) - 1];
	if (*p == '.')
		*p-- = CNULL;
	for ( ; p && *p && *p == '/' && p != file; --p)
		*p = CNULL;

	/*
	 * If this file is a symlink we really want the parent directory
	 * name in case the symlink points to another filesystem.
	 */
	if (S_ISLNK(filestat.st_mode))
		if ((p = (char *) strrchr(file, '/')) && *p+1) {
			/* Is this / (root)? */
			if (p == file)
				file[1] = CNULL;
			else
				*p = CNULL;
		}

	if (strcmp(pathname, file) == 0)
		*isvalid = 1;

	return((file && *file) ? file : NULL);
}

#if defined(NFS_CHECK) || defined(RO_CHECK)

/*
 * Find the device that "filest" is on in the "mntinfo" linked list.
 */
mntent_t *
findmnt(struct stat *filest, struct mntinfo *mntinfo)
{
	struct mntinfo *mi;

	for (mi = mntinfo; mi; mi = mi->mi_nxt) {
		if (mi->mi_mnt->me_flags & MEFLAG_IGNORE)
			continue;
		if (filest->st_dev == mi->mi_statb->st_dev)
			return(mi->mi_mnt);
	}

	return(NULL);
}

/*
 * Is "mnt" a duplicate of any of the mntinfo->mi_mnt elements?
 */
int
isdupmnt(mntent_t *mnt, struct mntinfo *mntinfo)
{
	struct mntinfo *m;

	for (m = mntinfo; m; m = m->mi_nxt)
		if (strcmp(m->mi_mnt->me_path, mnt->me_path) == 0)
			return(1);

	return(0);
}

/*
 * Alarm clock
 */
void
wakeup(int dummy)
{
	debugmsg(DM_CALL, "wakeup() in filesys.c called");
	longjmp(env, 1);
}

/*
 * Make a linked list of mntinfo structures.
 * Use "mi" as the base of the list if it's non NULL.
 */
struct mntinfo *
makemntinfo(struct mntinfo *mi)
{
	FILE *mfp;
	static struct mntinfo *mntinfo;
	struct mntinfo *newmi, *m;
	struct stat mntstat;
	mntent_t *mnt;
	int timeo = 310;

	if (!(mfp = setmountent(MOUNTED_FILE, "r"))) {
		message(MT_NERROR, "%s: setmntent failed: %s", 
			MOUNTED_FILE, SYSERR);
		return(NULL);
	}

	(void) signal(SIGALRM, wakeup);
	(void) alarm(timeo);
	if (setjmp(env)) {
		message(MT_NERROR, "Timeout getting mount info");
		return(NULL);
	}

	mntinfo = mi;
	while ((mnt = getmountent(mfp)) != NULL) {
		debugmsg(DM_MISC, "mountent = '%s' (%s)", 
			 mnt->me_path, mnt->me_type);

		/*
		 * Make sure we don't already have it for some reason
		 */
		if (isdupmnt(mnt, mntinfo))
			continue;

		/*
		 * Get stat info
		 */
		if (stat(mnt->me_path, &mntstat) != 0) {
			message(MT_WARNING, "%s: Cannot stat filesystem: %s", 
				mnt->me_path, SYSERR);
			continue;
		}

		/*
		 * Create new entry
		 */
		newmi = (struct mntinfo *) xcalloc(1, sizeof(struct mntinfo));
		newmi->mi_mnt = newmountent(mnt);
		newmi->mi_statb = 
		    (struct stat *) xcalloc(1, sizeof(struct stat));
		bcopy((char *) &mntstat, (char *) newmi->mi_statb, 
		      sizeof(struct stat));

		/*
		 * Add entry to list
		 */
		if (mntinfo) {
			for (m = mntinfo; m->mi_nxt; m = m->mi_nxt)
				continue;
			m->mi_nxt = newmi;
		} else
			mntinfo = newmi;
	}

	(void) alarm(0);
	(void) endmountent(mfp);

	return(mntinfo);
}

/*
 * Given a name like /usr/src/etc/foo.c returns the mntent
 * structure for the file system it lives in.
 *
 * If "statbuf" is not NULL it is used as the stat buffer too avoid
 * stat()'ing the file again back in server.c.
 */
mntent_t *
getmntpt(char *pathname, struct stat *statbuf, int *isvalid)
{
	static struct mntinfo *mntinfo = NULL;
	static struct stat filestat;
	struct stat *pstat;
	struct mntinfo *tmpmi;
	mntent_t *mnt;

	/*
	 * Use the supplied stat buffer if not NULL or our own.
	 */
	if (statbuf) 
		pstat = statbuf;
	else
		pstat = &filestat;

	if (!find_file(pathname, pstat, isvalid))
	        return(NULL);

	/*
	 * Make mntinfo if it doesn't exist.
	 */
	if (!mntinfo)
		mntinfo = makemntinfo(NULL);

	/*
	 * Find the mnt that pathname is on.
	 */
	if ((mnt = findmnt(pstat, mntinfo)) != NULL)
		return(mnt);

	/*
	 * We failed to find correct mnt, so maybe it's a newly
	 * mounted filesystem.  We rebuild mntinfo and try again.
	 */
	if ((tmpmi = makemntinfo(mntinfo)) != NULL) {
		mntinfo = tmpmi;
		if ((mnt = findmnt(pstat, mntinfo)) != NULL)
			return(mnt);
	}

	error("%s: Could not find mount point", pathname);
	return(NULL);
}

#endif /* NFS_CHECK || RO_CHECK */

#if	defined(NFS_CHECK)
/*
 * Is "path" NFS mounted?  Return 1 if it is, 0 if not, or -1 on error.
 */
int
is_nfs_mounted(char *path, struct stat *statbuf, int *isvalid)
{
	mntent_t *mnt;

	if ((mnt = (mntent_t *) getmntpt(path, statbuf, isvalid)) == NULL)
		return(-1);

	/*
	 * We treat "cachefs" just like NFS
	 */
	if ((strcmp(mnt->me_type, METYPE_NFS) == 0) ||
	    (strcmp(mnt->me_type, "cachefs") == 0))
		return(1);

	return(0);
}
#endif	/* NFS_CHECK */

#if	defined(RO_CHECK)
/*
 * Is "path" on a read-only mounted filesystem?  
 * Return 1 if it is, 0 if not, or -1 on error.
 */
int
is_ro_mounted(char *path, struct stat *statbuf, int *isvalid)
{
	mntent_t *mnt;

	if ((mnt = (mntent_t *) getmntpt(path, statbuf, isvalid)) == NULL)
		return(-1);

	if (mnt->me_flags & MEFLAG_READONLY)
		return(1);

	return(0);
}
#endif	/* RO_CHECK */

/*
 * Is "path" a symlink?
 * Return 1 if it is, 0 if not, or -1 on error.
 */
int
is_symlinked(char *path, struct stat *statbuf, int *isvalid)
{
	static struct stat stb;

	if (!(*isvalid)) {
		if (lstat(path, &stb) != 0)
			return(-1);
		statbuf = &stb;
	}
	
	if (S_ISLNK(statbuf->st_mode))
		return(1);

	return(0);
}

/*
 * Get filesystem information for "file".  Set freespace
 * to the amount of free (available) space and number of free
 * files (inodes) on the filesystem "file" resides on.
 * Returns 0 on success or -1 on failure.
 * Filesystem values < 0 indicate unsupported or unavailable
 * information.
 */
int
getfilesysinfo(char *file, long *freespace, long *freefiles)
{
#if	defined(STATFS_TYPE)
	static statfs_t statfsbuf;
	char *mntpt;
	int t, r;

	/*
	 * Get the mount point of the file.
	 */
	mntpt = find_file(file, NULL, &t);
	if (!mntpt) {
		debugmsg(DM_MISC, "unknown mount point for `%s'", file);
		return(-1);
	}

	/*
	 * Stat the filesystem (system specific)
	 */
#if	STATFS_TYPE == STATFS_SYSV
	r = statfs(mntpt, &statfsbuf, sizeof(statfs_t), 0);
#endif
#if	STATFS_TYPE == STATFS_BSD || STATFS_TYPE == STATFS_44BSD
	r = statfs(mntpt, &statfsbuf);
#endif
#if	STATFS_TYPE == STATFS_OSF1
	r = statfs(mntpt, &statfsbuf, sizeof(statfs_t));
#endif

	if (r < 0) {
		error("%s: Cannot statfs filesystem: %s.", mntpt, SYSERR);
		return(-1);
	}

	/*
	 * If values are < 0, then assume the value is unsupported
	 * or unavailable for that filesystem type.
	 */
	if (statfsbuf.f_bavail >= 0)
		*freespace = (statfsbuf.f_bavail * (statfsbuf.f_bsize / 512))
			      / 2;

	/*
	 * BROKEN_STATFS means that statfs() does not set fields
	 * to < 0 if the field is unsupported for the filesystem type.
	 */
#if	defined(BROKEN_STATFS)
	if (statfsbuf.f_ffree > 0)
#else
	if (statfsbuf.f_ffree >= 0)
#endif 	/* BROKEN_STATFS */
		*freefiles = statfsbuf.f_ffree;

#else	/* !STATFS_TYPE */

    	*freespace = *freefiles = -1;

#endif	/* STATFS_TYPE */

	return(0);
}