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/*
* lib / parser . c - simple parser for mount , etc . options .
*
* This source code is licensed under the GNU General Public License ,
* Version 2. See the file COPYING for more details .
*/
# include <linux/ctype.h>
# include <linux/module.h>
# include <linux/parser.h>
# include <linux/slab.h>
# include <linux/string.h>
/**
* match_one : - Determines if a string matches a simple pattern
* @ s : the string to examine for presense of the pattern
* @ p : the string containing the pattern
* @ args : array of % MAX_OPT_ARGS & substring_t elements . Used to return match
* locations .
*
* Description : Determines if the pattern @ p is present in string @ s . Can only
* match extremely simple token = arg style patterns . If the pattern is found ,
* the location ( s ) of the arguments will be returned in the @ args array .
*/
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static int match_one ( char * s , const char * p , substring_t args [ ] )
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{
char * meta ;
int argc = 0 ;
if ( ! p )
return 1 ;
while ( 1 ) {
int len = - 1 ;
meta = strchr ( p , ' % ' ) ;
if ( ! meta )
return strcmp ( p , s ) = = 0 ;
if ( strncmp ( p , s , meta - p ) )
return 0 ;
s + = meta - p ;
p = meta + 1 ;
if ( isdigit ( * p ) )
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len = simple_strtoul ( p , ( char * * ) & p , 10 ) ;
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else if ( * p = = ' % ' ) {
if ( * s + + ! = ' % ' )
return 0 ;
p + + ;
continue ;
}
if ( argc > = MAX_OPT_ARGS )
return 0 ;
args [ argc ] . from = s ;
switch ( * p + + ) {
case ' s ' :
if ( strlen ( s ) = = 0 )
return 0 ;
else if ( len = = - 1 | | len > strlen ( s ) )
len = strlen ( s ) ;
args [ argc ] . to = s + len ;
break ;
case ' d ' :
simple_strtol ( s , & args [ argc ] . to , 0 ) ;
goto num ;
case ' u ' :
simple_strtoul ( s , & args [ argc ] . to , 0 ) ;
goto num ;
case ' o ' :
simple_strtoul ( s , & args [ argc ] . to , 8 ) ;
goto num ;
case ' x ' :
simple_strtoul ( s , & args [ argc ] . to , 16 ) ;
num :
if ( args [ argc ] . to = = args [ argc ] . from )
return 0 ;
break ;
default :
return 0 ;
}
s = args [ argc ] . to ;
argc + + ;
}
}
/**
* match_token : - Find a token ( and optional args ) in a string
* @ s : the string to examine for token / argument pairs
* @ table : match_table_t describing the set of allowed option tokens and the
* arguments that may be associated with them . Must be terminated with a
* & struct match_token whose pattern is set to the NULL pointer .
* @ args : array of % MAX_OPT_ARGS & substring_t elements . Used to return match
* locations .
*
* Description : Detects which if any of a set of token strings has been passed
* to it . Tokens can include up to MAX_OPT_ARGS instances of basic c - style
* format identifiers which will be taken into account when matching the
* tokens , and whose locations will be returned in the @ args array .
*/
int match_token ( char * s , match_table_t table , substring_t args [ ] )
{
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const struct match_token * p ;
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for ( p = table ; ! match_one ( s , p - > pattern , args ) ; p + + )
;
return p - > token ;
}
/**
* match_number : scan a number in the given base from a substring_t
* @ s : substring to be scanned
* @ result : resulting integer on success
* @ base : base to use when converting string
*
* Description : Given a & substring_t and a base , attempts to parse the substring
* as a number in that base . On success , sets @ result to the integer represented
* by the string and returns 0. Returns either - ENOMEM or - EINVAL on failure .
*/
static int match_number ( substring_t * s , int * result , int base )
{
char * endp ;
char * buf ;
int ret ;
buf = kmalloc ( s - > to - s - > from + 1 , GFP_KERNEL ) ;
if ( ! buf )
return - ENOMEM ;
memcpy ( buf , s - > from , s - > to - s - > from ) ;
buf [ s - > to - s - > from ] = ' \0 ' ;
* result = simple_strtol ( buf , & endp , base ) ;
ret = 0 ;
if ( endp = = buf )
ret = - EINVAL ;
kfree ( buf ) ;
return ret ;
}
/**
* match_int : - scan a decimal representation of an integer from a substring_t
* @ s : substring_t to be scanned
* @ result : resulting integer on success
*
* Description : Attempts to parse the & substring_t @ s as a decimal integer . On
* success , sets @ result to the integer represented by the string and returns 0.
* Returns either - ENOMEM or - EINVAL on failure .
*/
int match_int ( substring_t * s , int * result )
{
return match_number ( s , result , 0 ) ;
}
/**
* match_octal : - scan an octal representation of an integer from a substring_t
* @ s : substring_t to be scanned
* @ result : resulting integer on success
*
* Description : Attempts to parse the & substring_t @ s as an octal integer . On
* success , sets @ result to the integer represented by the string and returns
* 0. Returns either - ENOMEM or - EINVAL on failure .
*/
int match_octal ( substring_t * s , int * result )
{
return match_number ( s , result , 8 ) ;
}
/**
* match_hex : - scan a hex representation of an integer from a substring_t
* @ s : substring_t to be scanned
* @ result : resulting integer on success
*
* Description : Attempts to parse the & substring_t @ s as a hexadecimal integer .
* On success , sets @ result to the integer represented by the string and
* returns 0. Returns either - ENOMEM or - EINVAL on failure .
*/
int match_hex ( substring_t * s , int * result )
{
return match_number ( s , result , 16 ) ;
}
/**
* match_strcpy : - copies the characters from a substring_t to a string
* @ to : string to copy characters to .
* @ s : & substring_t to copy
*
* Description : Copies the set of characters represented by the given
* & substring_t @ s to the c - style string @ to . Caller guarantees that @ to is
* large enough to hold the characters of @ s .
*/
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void match_strcpy ( char * to , const substring_t * s )
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{
memcpy ( to , s - > from , s - > to - s - > from ) ;
to [ s - > to - s - > from ] = ' \0 ' ;
}
/**
* match_strdup : - allocate a new string with the contents of a substring_t
* @ s : & substring_t to copy
*
* Description : Allocates and returns a string filled with the contents of
* the & substring_t @ s . The caller is responsible for freeing the returned
* string with kfree ( ) .
*/
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char * match_strdup ( const substring_t * s )
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{
char * p = kmalloc ( s - > to - s - > from + 1 , GFP_KERNEL ) ;
if ( p )
match_strcpy ( p , s ) ;
return p ;
}
EXPORT_SYMBOL ( match_token ) ;
EXPORT_SYMBOL ( match_int ) ;
EXPORT_SYMBOL ( match_octal ) ;
EXPORT_SYMBOL ( match_hex ) ;
EXPORT_SYMBOL ( match_strcpy ) ;
EXPORT_SYMBOL ( match_strdup ) ;