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/*
* lookup_file.c
*
* Module for Linux automountd to access a plain file automount map
*/
#include <stdio.h>
#include <malloc.h>
#include <errno.h>
#include <unistd.h>
#include <ctype.h>
#include <syslog.h>
#include <sys/param.h>
#include <sys/types.h>
#include <sys/stat.h>
#define MODULE_LOOKUP
#include "automount.h"
#define MAPFMT_DEFAULT "sun"
#define MODPREFIX "lookup(file): "
#define MAPENT_MAX_LEN 4095
struct lookup_context {
char *mapname;
struct parse_mod *parse;
};
int lookup_version = AUTOFS_LOOKUP_VERSION; /* Required by protocol */
int lookup_init(char *mapfmt, int argc, char **argv, void **context)
{
struct lookup_context *ctxt;
if ( !(*context = ctxt = malloc(sizeof(struct lookup_context))) ) {
syslog(LOG_CRIT, MODPREFIX "malloc: %m");
return 1;
}
if ( argc < 1 ) {
syslog(LOG_CRIT, MODPREFIX "No map name");
return 1;
}
ctxt->mapname = argv[0];
if (ctxt->mapname[0] != '/') {
syslog(LOG_CRIT, MODPREFIX "file map %s is not an absolute pathname",
ctxt->mapname);
return 1;
}
if ( access(ctxt->mapname, R_OK) ) {
syslog(LOG_WARNING, MODPREFIX "file map %s missing or not readable",
ctxt->mapname);
}
if ( !mapfmt )
mapfmt = MAPFMT_DEFAULT;
return !(ctxt->parse = open_parse(mapfmt,MODPREFIX,argc-1,argv+1));
}
int lookup_mount(char *root, char *name, int name_len, void *context)
{
struct lookup_context *ctxt = (struct lookup_context *) context;
int ch, nch;
char mapent[MAPENT_MAX_LEN+1], *p, *nptr;
int mapent_len;
FILE *f;
enum {
st_begin, st_compare, st_star, st_badent, st_entspc, st_getent
} state;
enum { got_nothing, got_star, got_real } getting, gotten;
enum { esc_none, esc_char, esc_val } escape;
syslog(LOG_DEBUG, MODPREFIX "looking up %s", name);
chdir("/"); /* If this is not here the filesystem stays
busy, for some reason... */
f = fopen(ctxt->mapname, "r");
if ( !f ) {
syslog(LOG_ERR, MODPREFIX "could not open map file %s", ctxt->mapname);
return 1;
}
state = st_begin;
gotten = got_nothing;
/* Shut up gcc */
p = nptr = NULL;
mapent_len = 0;
getting = got_nothing;
escape = esc_none;
/* This is ugly. We can't just remove \ escape sequences in the value
portion of an entry, because the parsing routine may need it. */
while ( (ch = getc(f)) != EOF ) {
switch ( escape ) {
case esc_none:
if ( ch == '\\' ) {
/* Handle continuation lines */
if ( (nch = getc(f)) == '\n' )
goto next_char;
ungetc(nch,f);
escape = esc_char;
}
break;
case esc_char:
escape = esc_val;
break;
case esc_val:
escape = esc_none;
break;
}
switch(state) {
case st_begin:
if ( isspace(ch) && !escape )
;
else if ( escape == esc_char )
;
else if ( ch == '#' && !escape )
state = st_badent;
else if ( (char)ch == name[0] ) {
state = st_compare;
nptr = name+1;
} else if ( ch == '*' && !escape )
state = st_star;
else
state = st_badent;
break;
case st_compare:
if ( ch == '\n' )
state = st_begin;
else if ( isspace(ch) && !*nptr && !escape ) {
getting = got_real;
state = st_entspc;
} else if ( escape == esc_char )
;
else if ( (char)ch != *(nptr++) )
state = st_badent;
break;
case st_star:
if ( ch == '\n' )
state = st_begin;
else if ( isspace(ch) && gotten < got_star && !escape ) {
getting = got_star;
state = st_entspc;
} else if ( escape != esc_char )
state = st_badent;
break;
case st_badent:
if ( ch == '\n' )
state = st_begin;
break;
case st_entspc:
if ( ch == '\n' )
state = st_begin;
else if ( !isspace(ch) || escape ) {
state = st_getent;
p = mapent;
gotten = getting;
*(p++) = ch;
mapent_len = 1;
}
break;
case st_getent:
if ( ch == '\n' ) {
state = st_begin;
if ( gotten == got_real )
goto got_it; /* No point in parsing the rest of the file */
} else if ( mapent_len < MAPENT_MAX_LEN ) {
mapent_len++;
*(p++) = ch;
}
break;
}
next_char: /* End of loop, since we can't continue;
inside a switch */
}
got_it:
fclose(f);
if ( gotten == got_nothing ) {
syslog(LOG_NOTICE, MODPREFIX "lookup for %s failed", name);
return 1; /* Didn't found anything */
}
*p = '\0'; /* Null-terminate */
syslog(LOG_DEBUG, MODPREFIX "%s -> %s", name, mapent);
return ctxt->parse->parse_mount(root,name,name_len,mapent,ctxt->parse->context);
}
int lookup_done(void *context)
{
struct lookup_context *ctxt = (struct lookup_context *) context;
int rv = close_parse(ctxt->parse);
free(ctxt);
return rv;
}
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