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