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/* ISC license. */
#include <string.h>
#include <errno.h>
#include <stdlib.h>
#include <skalibs/error.h>
#include <skalibs/bytestr.h>
#include <skalibs/bitarray.h>
#include <skalibs/fmtscan.h>
#include <skalibs/djbunix.h>
#include <skalibs/stralloc.h>
#include <skalibs/ip46.h>
#include <s6-dns/s6dns-constants.h>
#include <s6-dns/s6dns-rci.h>
static size_t readit (char const *file, char *buf, size_t max)
{
ssize_t r = openreadnclose(file, buf, max - 1) ;
if (r < 0)
{
if (errno != ENOENT) return 0 ;
else r = 0 ;
}
buf[r++] = '\n' ;
return r ;
}
static inline int s6dns_rci_init_servers (s6dns_rci_t *rci, char const *file, char *tmp, size_t max, size_t *size)
{
ip46 tmplist[S6DNS_MAX_SERVERS] ;
size_t num = 0 ;
char const *x = getenv("DNSCACHEIP") ;
if (x) ip46_scanlist(tmplist, S6DNS_MAX_SERVERS, x, &num) ;
if (!num)
{
size_t i = 0 ;
*size = readit(file, tmp, max) ;
if (!*size) return 0 ;
while ((i < *size) && (num < S6DNS_MAX_SERVERS))
{
size_t j = byte_chr(tmp + i, *size - i, '\n') ;
if ((i + j < *size) && (j > 13U) && !memcmp("nameserver", tmp + i, 10))
{
size_t k = 0 ;
while ((tmp[i+10+k] == ' ') || (tmp[i+10+k] == '\t')) k++ ;
if (k && ip46_scan(tmp+i+10+k, tmplist + num)) num++ ;
}
i += j + 1 ;
}
}
if (!num)
{
num = 1 ;
memcpy(tmplist[0].ip, S6DNS_LOCALHOST_IP, SKALIBS_IP_SIZE) ;
#ifdef SKALIBS_IPV6_ENABLED
tmplist[0].is6 = 1 ;
#endif
}
{
unsigned int i = 0 ;
memset(&rci->servers, 0, sizeof(s6dns_ip46list_t)) ;
for (; i < num ; i++)
{
memcpy(rci->servers.ip + SKALIBS_IP_SIZE * i, tmplist[i].ip, SKALIBS_IP_SIZE) ;
#ifdef SKALIBS_IPV6_ENABLED
if (ip46_is6(tmplist+i)) bitarray_set(rci->servers.is6, i) ;
#endif
}
}
return 1 ;
}
static inline int stringrules (stralloc *rules, char const *s, unsigned int *num)
{
size_t base = rules->len ;
int wasnull = !rules->s ;
unsigned int n = 0 ;
int crunching = 1 ;
char c = ' ' ;
while (c)
{
c = *s++ ;
if (memchr(" \t\n\r", c, 5))
{
if (!crunching)
{
if ((rules->s[rules->len - 1] != '.') && !stralloc_catb(rules, ".", 1)) goto err ;
if (!stralloc_0(rules)) goto err ;
n++ ;
crunching = 1 ;
}
}
else
{
if (crunching) crunching = 0 ;
if (!stralloc_catb(rules, &c, 1)) goto err ;
}
}
*num += n ;
return 1 ;
err:
if (wasnull) stralloc_free(rules) ;
else rules->len = base ;
return 0 ;
}
static inline int s6dns_rci_init_rules (s6dns_rci_t_ref rci, char const *file, char *tmp, size_t max, size_t *size)
{
unsigned int num = 0 ;
char const *x = getenv("DNSQUALIFY") ;
if (x)
{
if (!stringrules(&rci->rules, x, &num)) return 0 ;
}
else
{
size_t i = 0 ;
if (!*size)
{
*size = readit(file, tmp, max) ;
if (!*size) return 0 ;
}
while (i < *size)
{
size_t j = byte_chr(tmp + i, *size - i, '\n') ;
if ((i + j < *size) && (j > 8U)
&& (!memcmp("domain", tmp + i, 6) || !memcmp("search", tmp + i, 6))
&& ((tmp[i+6] == ' ') || (tmp[i+6] == '\t') || (tmp[i+6] == '\r')))
{
size_t k = 0 ;
int copying = 0 ;
int notsearching = (tmp[i] != 's') ;
if (!stralloc_readyplus(&rci->rules, j)) return 0 ;
for (; 6 + k < j ; k++)
{
char c = tmp[i+7+k] ;
if ((c == ' ') || (c == '\t') || (c == '\r') || (c == '\n'))
{
if (copying)
{
copying = 0 ;
if ((tmp[i+6+k] != '.') && !stralloc_catb(&rci->rules, ".", 1)) return 0 ;
if (!stralloc_0(&rci->rules)) return 0 ;
num++ ;
if (notsearching) break ;
}
}
else
{
copying = 1 ;
if (!stralloc_catb(&rci->rules, &c, 1)) return 0 ;
}
}
}
i += j + 1 ;
}
}
if (!stralloc_0(&rci->rules)) return 0 ; /* empty rule to finish */
num++ ;
rci->rulesnum = num ;
stralloc_shrink(&rci->rules) ;
return 1 ;
}
int s6dns_rci_init (s6dns_rci_t *rci, char const *file)
{
char tmp[4096] ;
size_t size = 0 ;
if (!s6dns_rci_init_servers(rci, file, tmp, 4096, &size)) return 0 ;
if (!s6dns_rci_init_rules(rci, file, tmp, 4096, &size)) return 0 ;
return 1 ;
}
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