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