X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=blobdiff_plain;f=src%2Fnss-resolve%2Fnss-resolve.c;h=b2cb19a7b42918afd2dbb21ed50ecf88352d5156;hp=c67f59e17910efa9cc6d3fbf2bc54f4e65592dab;hb=7c2a5e264c1d94ca9ba9c49acfdcd541c8a63a88;hpb=9d485985338a46b8cb1acdf1af6c1eb2e88acfee diff --git a/src/nss-resolve/nss-resolve.c b/src/nss-resolve/nss-resolve.c index c67f59e17..b2cb19a7b 100644 --- a/src/nss-resolve/nss-resolve.c +++ b/src/nss-resolve/nss-resolve.c @@ -29,6 +29,7 @@ #include #include #include +#include #include "sd-bus.h" #include "bus-util.h" @@ -43,20 +44,41 @@ NSS_GETHOSTBYADDR_PROTOTYPES(resolve); #define DNS_CALL_TIMEOUT_USEC (45*USEC_PER_SEC) -static int count_addresses(sd_bus_message *m, unsigned af, const char **canonical) { +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; assert(m); assert(canonical); - r = sd_bus_message_enter_container(m, 'a', "(yayi)"); + r = sd_bus_message_enter_container(m, 'a', "(iayi)"); if (r < 0) return r; - while ((r = sd_bus_message_enter_container(m, 'r', "yayi")) > 0) { - unsigned char family; + while ((r = sd_bus_message_enter_container(m, 'r', "iayi")) > 0) { + int family; - r = sd_bus_message_read(m, "y", &family); + r = sd_bus_message_read(m, "i", &family); if (r < 0) return r; @@ -131,7 +153,7 @@ enum nss_status _nss_resolve_gethostbyname4_r( if (r < 0) goto fail; - r = sd_bus_message_append(req, "sy", name, AF_UNSPEC); + r = sd_bus_message_append(req, "si", name, AF_UNSPEC); if (r < 0) goto fail; @@ -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; @@ -178,17 +219,16 @@ enum nss_status _nss_resolve_gethostbyname4_r( /* Second, append addresses */ r_tuple_first = (struct gaih_addrtuple*) (buffer + idx); - r = sd_bus_message_enter_container(reply, 'a', "(yayi)"); + r = sd_bus_message_enter_container(reply, 'a', "(iayi)"); if (r < 0) goto fail; - while ((r = sd_bus_message_enter_container(reply, 'r', "yayi")) > 0) { - unsigned char family; + while ((r = sd_bus_message_enter_container(reply, 'r', "iayi")) > 0) { + int family, ifindex; const void *a; - int ifindex; size_t sz; - r = sd_bus_message_read(reply, "y", &family); + r = sd_bus_message_read(reply, "i", &family); if (r < 0) goto fail; @@ -298,7 +338,7 @@ enum nss_status _nss_resolve_gethostbyname3_r( if (r < 0) goto fail; - r = sd_bus_message_append(req, "sy", name, af); + r = sd_bus_message_append(req, "si", name, af); if (r < 0) goto fail; @@ -310,6 +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; @@ -356,17 +419,16 @@ enum nss_status _nss_resolve_gethostbyname3_r( /* Third, append addresses */ r_addr = buffer + idx; - r = sd_bus_message_enter_container(reply, 'a', "(yayi)"); + r = sd_bus_message_enter_container(reply, 'a', "(iayi)"); if (r < 0) goto fail; - while ((r = sd_bus_message_enter_container(reply, 'r', "yayi")) > 0) { - unsigned char family; + while ((r = sd_bus_message_enter_container(reply, 'r', "iayi")) > 0) { + int family, ifindex; const void *a; - int ifindex; size_t sz; - r = sd_bus_message_read(reply, "y", &family); + r = sd_bus_message_read(reply, "i", &family); if (r < 0) goto fail; @@ -487,7 +549,7 @@ enum nss_status _nss_resolve_gethostbyaddr2_r( if (r < 0) goto fail; - r = sd_bus_message_append(req, "y", af); + r = sd_bus_message_append(req, "i", af); if (r < 0) goto fail; @@ -507,6 +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;