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      1 /*
      2  * mountopts.c --- convert between default mount options and strings
      3  *
      4  * Copyright (C) 2002  Theodore Ts'o <tytso (at) mit.edu>
      5  *
      6  * %Begin-Header%
      7  * This file may be redistributed under the terms of the GNU Library
      8  * General Public License, version 2.
      9  * %End-Header%
     10  */
     11 
     12 #include "config.h"
     13 #include <stdio.h>
     14 #include <stdlib.h>
     15 #include <string.h>
     16 #include <strings.h>
     17 #include <ctype.h>
     18 #include <errno.h>
     19 
     20 #include "e2p.h"
     21 
     22 struct mntopt {
     23 	unsigned int	mask;
     24 	const char	*string;
     25 };
     26 
     27 static struct mntopt mntopt_list[] = {
     28 	{ EXT2_DEFM_DEBUG,	"debug" },
     29 	{ EXT2_DEFM_BSDGROUPS,	"bsdgroups" },
     30 	{ EXT2_DEFM_XATTR_USER,	"user_xattr" },
     31 	{ EXT2_DEFM_ACL,	"acl" },
     32 	{ EXT2_DEFM_UID16,	"uid16" },
     33 	{ EXT3_DEFM_JMODE_DATA, "journal_data" },
     34 	{ EXT3_DEFM_JMODE_ORDERED, "journal_data_ordered" },
     35 	{ EXT3_DEFM_JMODE_WBACK, "journal_data_writeback" },
     36 	{ EXT4_DEFM_NOBARRIER,	"nobarrier" },
     37 	{ EXT4_DEFM_BLOCK_VALIDITY, "block_validity" },
     38 	{ EXT4_DEFM_DISCARD,	"discard"},
     39 	{ EXT4_DEFM_NODELALLOC,	"nodelalloc"},
     40 	{ 0, 0 },
     41 };
     42 
     43 const char *e2p_mntopt2string(unsigned int mask)
     44 {
     45 	struct mntopt  *f;
     46 	static char buf[20];
     47 	int	fnum;
     48 
     49 	for (f = mntopt_list; f->string; f++) {
     50 		if (mask == f->mask)
     51 			return f->string;
     52 	}
     53 	for (fnum = 0; mask >>= 1; fnum++);
     54 	sprintf(buf, "MNTOPT_%d", fnum);
     55 	return buf;
     56 }
     57 
     58 int e2p_string2mntopt(char *string, unsigned int *mask)
     59 {
     60 	struct mntopt  *f;
     61 	char		*eptr;
     62 	int		num;
     63 
     64 	for (f = mntopt_list; f->string; f++) {
     65 		if (!strcasecmp(string, f->string)) {
     66 			*mask = f->mask;
     67 			return 0;
     68 		}
     69 	}
     70 	if (strncasecmp(string, "MNTOPT_", 7))
     71 		return 1;
     72 
     73 	if (string[8] == 0)
     74 		return 1;
     75 	num = strtol(string+8, &eptr, 10);
     76 	if (num > 31 || num < 0)
     77 		return 1;
     78 	if (*eptr)
     79 		return 1;
     80 	*mask = 1 << num;
     81 	return 0;
     82 }
     83 
     84 static char *skip_over_blanks(char *cp)
     85 {
     86 	while (*cp && isspace(*cp))
     87 		cp++;
     88 	return cp;
     89 }
     90 
     91 static char *skip_over_word(char *cp)
     92 {
     93 	while (*cp && !isspace(*cp) && *cp != ',')
     94 		cp++;
     95 	return cp;
     96 }
     97 
     98 /*
     99  * Edit a mntopt set array as requested by the user.  The ok
    100  * parameter, if non-zero, allows the application to limit what
    101  * mntopts the user is allowed to set or clear using this function.
    102  */
    103 int e2p_edit_mntopts(const char *str, __u32 *mntopts, __u32 ok)
    104 {
    105 	char	*cp, *buf, *next;
    106 	int	neg;
    107 	unsigned int	mask;
    108 	int	rc = 0;
    109 
    110 	buf = malloc(strlen(str)+1);
    111 	if (!buf)
    112 		return 1;
    113 	strcpy(buf, str);
    114 	cp = buf;
    115 	while (cp && *cp) {
    116 		neg = 0;
    117 		cp = skip_over_blanks(cp);
    118 		next = skip_over_word(cp);
    119 		if (*next == 0)
    120 			next = 0;
    121 		else
    122 			*next = 0;
    123 		switch (*cp) {
    124 		case '-':
    125 		case '^':
    126 			neg++;
    127 			/* fallthrough */
    128 		case '+':
    129 			cp++;
    130 			break;
    131 		}
    132 		if (e2p_string2mntopt(cp, &mask)) {
    133 			rc = 1;
    134 			break;
    135 		}
    136 		if (ok && !(ok & mask)) {
    137 			rc = 1;
    138 			break;
    139 		}
    140 		if (mask & EXT3_DEFM_JMODE)
    141 			*mntopts &= ~EXT3_DEFM_JMODE;
    142 		if (neg)
    143 			*mntopts &= ~mask;
    144 		else
    145 			*mntopts |= mask;
    146 		cp = next ? next+1 : 0;
    147 	}
    148 	free(buf);
    149 	return rc;
    150 }
    151