mirror of
https://github.com/systemd/systemd.git
synced 2024-12-25 01:34:28 +03:00
nss-resolve: fallback to the class NSS "dns" module if we cannot contact resolved
That way DNS resolution works both with and without resolved running.
This commit is contained in:
parent
95dd6257a6
commit
7c2a5e264c
@ -29,6 +29,7 @@
|
||||
#include <net/if.h>
|
||||
#include <stdlib.h>
|
||||
#include <arpa/inet.h>
|
||||
#include <dlfcn.h>
|
||||
|
||||
#include "sd-bus.h"
|
||||
#include "bus-util.h"
|
||||
@ -43,6 +44,27 @@ NSS_GETHOSTBYADDR_PROTOTYPES(resolve);
|
||||
|
||||
#define DNS_CALL_TIMEOUT_USEC (45*USEC_PER_SEC)
|
||||
|
||||
typedef void (*voidfunc_t)(void);
|
||||
|
||||
static voidfunc_t find_fallback(const char *module, const char *symbol) {
|
||||
void *dl;
|
||||
|
||||
/* Try to find a fallback NSS module symbol */
|
||||
|
||||
dl = dlopen(module, RTLD_LAZY|RTLD_NODELETE);
|
||||
if (!dl)
|
||||
return NULL;
|
||||
|
||||
return dlsym(dl, symbol);
|
||||
}
|
||||
|
||||
static bool bus_error_shall_fallback(sd_bus_error *e) {
|
||||
return sd_bus_error_has_name(e, SD_BUS_ERROR_SERVICE_UNKNOWN) ||
|
||||
sd_bus_error_has_name(e, SD_BUS_ERROR_NAME_HAS_NO_OWNER) ||
|
||||
sd_bus_error_has_name(e, SD_BUS_ERROR_NO_REPLY) ||
|
||||
sd_bus_error_has_name(e, SD_BUS_ERROR_ACCESS_DENIED);
|
||||
}
|
||||
|
||||
static int count_addresses(sd_bus_message *m, int af, const char **canonical) {
|
||||
int c = 0, r;
|
||||
|
||||
@ -143,6 +165,25 @@ enum nss_status _nss_resolve_gethostbyname4_r(
|
||||
return NSS_STATUS_NOTFOUND;
|
||||
}
|
||||
|
||||
if (bus_error_shall_fallback(&error)) {
|
||||
|
||||
enum nss_status (*fallback)(
|
||||
const char *name,
|
||||
struct gaih_addrtuple **pat,
|
||||
char *buffer, size_t buflen,
|
||||
int *errnop, int *h_errnop,
|
||||
int32_t *ttlp);
|
||||
|
||||
fallback = (enum nss_status (*)(const char *name,
|
||||
struct gaih_addrtuple **pat,
|
||||
char *buffer, size_t buflen,
|
||||
int *errnop, int *h_errnop,
|
||||
int32_t *ttlp))
|
||||
find_fallback("libnss_dns.so.2", "_nss_dns_gethostbyname4_r");
|
||||
if (fallback)
|
||||
return fallback(name, pat, buffer, buflen, errnop, h_errnop, ttlp);
|
||||
}
|
||||
|
||||
*errnop = -r;
|
||||
*h_errnop = NO_RECOVERY;
|
||||
return NSS_STATUS_UNAVAIL;
|
||||
@ -309,6 +350,29 @@ enum nss_status _nss_resolve_gethostbyname3_r(
|
||||
return NSS_STATUS_NOTFOUND;
|
||||
}
|
||||
|
||||
if (bus_error_shall_fallback(&error)) {
|
||||
|
||||
enum nss_status (*fallback)(
|
||||
const char *name,
|
||||
int af,
|
||||
struct hostent *result,
|
||||
char *buffer, size_t buflen,
|
||||
int *errnop, int *h_errnop,
|
||||
int32_t *ttlp,
|
||||
char **canonp);
|
||||
|
||||
fallback = (enum nss_status (*)(const char *name,
|
||||
int af,
|
||||
struct hostent *result,
|
||||
char *buffer, size_t buflen,
|
||||
int *errnop, int *h_errnop,
|
||||
int32_t *ttlp,
|
||||
char **canonp))
|
||||
find_fallback("libnss_dns.so.2", "_nss_dns_gethostbyname3_r");
|
||||
if (fallback)
|
||||
return fallback(name, af, result, buffer, buflen, errnop, h_errnop, ttlp, canonp);
|
||||
}
|
||||
|
||||
*errnop = -r;
|
||||
*h_errnop = NO_RECOVERY;
|
||||
return NSS_STATUS_UNAVAIL;
|
||||
@ -505,6 +569,29 @@ enum nss_status _nss_resolve_gethostbyaddr2_r(
|
||||
return NSS_STATUS_NOTFOUND;
|
||||
}
|
||||
|
||||
if (bus_error_shall_fallback(&error)) {
|
||||
|
||||
enum nss_status (*fallback)(
|
||||
const void* addr, socklen_t len,
|
||||
int af,
|
||||
struct hostent *result,
|
||||
char *buffer, size_t buflen,
|
||||
int *errnop, int *h_errnop,
|
||||
int32_t *ttlp);
|
||||
|
||||
fallback = (enum nss_status (*)(
|
||||
const void* addr, socklen_t len,
|
||||
int af,
|
||||
struct hostent *result,
|
||||
char *buffer, size_t buflen,
|
||||
int *errnop, int *h_errnop,
|
||||
int32_t *ttlp))
|
||||
find_fallback("libnss_dns.so.2", "_nss_dns_gethostbyaddr2_r");
|
||||
|
||||
if (fallback)
|
||||
return fallback(addr, len, af, result, buffer, buflen, errnop, h_errnop, ttlp);
|
||||
}
|
||||
|
||||
*errnop = -r;
|
||||
*h_errnop = NO_RECOVERY;
|
||||
return NSS_STATUS_UNAVAIL;
|
||||
|
Loading…
Reference in New Issue
Block a user