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-rw-r--r--src/nss-myhostname/nss-myhostname.c180
1 files changed, 130 insertions, 50 deletions
diff --git a/src/nss-myhostname/nss-myhostname.c b/src/nss-myhostname/nss-myhostname.c
index 8699098b54..60e256d54f 100644
--- a/src/nss-myhostname/nss-myhostname.c
+++ b/src/nss-myhostname/nss-myhostname.c
@@ -32,7 +32,6 @@
#include "ifconf.h"
#include "macro.h"
-#include "util.h"
/* Ensure that glibc's assert is used. We cannot use assert from macro.h, as
* libnss_myhostname will be linked into arbitrary programs which will, in turn
@@ -101,31 +100,46 @@ enum nss_status _nss_myhostname_gethostbyname4_r(
unsigned lo_ifi;
char hn[HOST_NAME_MAX+1] = {};
+ const char *canonical = NULL;
size_t l, idx, ms;
char *r_name;
struct gaih_addrtuple *r_tuple, *r_tuple_prev = NULL;
struct address *addresses = NULL, *a;
unsigned n_addresses = 0, n;
+ uint32_t local_address_ipv4;
- if (gethostname(hn, sizeof(hn)-1) < 0) {
- *errnop = errno;
- *h_errnop = NO_RECOVERY;
- return NSS_STATUS_UNAVAIL;
- }
+ if (strcasecmp(name, "localhost") == 0) {
+ /* We respond to 'localhost', so that /etc/hosts
+ * is optional */
- if (strcasecmp(name, hn) != 0) {
- *errnop = ENOENT;
- *h_errnop = HOST_NOT_FOUND;
- return NSS_STATUS_NOTFOUND;
- }
+ canonical = "localhost";
+ local_address_ipv4 = htonl(INADDR_LOOPBACK);
+ } else {
+ /* We respond to our local host name */
- /* If this fails, n_addresses is 0. Which is fine */
- ifconf_acquire_addresses(&addresses, &n_addresses);
+ if (gethostname(hn, sizeof(hn)-1) < 0) {
+ *errnop = errno;
+ *h_errnop = NO_RECOVERY;
+ return NSS_STATUS_UNAVAIL;
+ }
+
+ if (strcasecmp(name, hn) != 0) {
+ *errnop = ENOENT;
+ *h_errnop = HOST_NOT_FOUND;
+ return NSS_STATUS_NOTFOUND;
+ }
+
+ /* If this fails, n_addresses is 0. Which is fine */
+ ifconf_acquire_addresses(&addresses, &n_addresses);
+
+ canonical = hn;
+ local_address_ipv4 = LOCALADDRESS_IPV4;
+ }
/* If this call fails we fill in 0 as scope. Which is fine */
- lo_ifi = if_nametoindex(LOOPBACK_INTERFACE);
+ lo_ifi = n_addresses <= 0 ? if_nametoindex(LOOPBACK_INTERFACE) : 0;
- l = strlen(hn);
+ l = strlen(canonical);
ms = ALIGN(l+1)+ALIGN(sizeof(struct gaih_addrtuple))*(n_addresses > 0 ? n_addresses : 2);
if (buflen < ms) {
*errnop = ENOMEM;
@@ -136,7 +150,7 @@ enum nss_status _nss_myhostname_gethostbyname4_r(
/* First, fill in hostname */
r_name = buffer;
- memcpy(r_name, hn, l+1);
+ memcpy(r_name, canonical, l+1);
idx = ALIGN(l+1);
if (n_addresses <= 0) {
@@ -156,7 +170,7 @@ enum nss_status _nss_myhostname_gethostbyname4_r(
r_tuple->next = r_tuple_prev;
r_tuple->name = r_name;
r_tuple->family = AF_INET;
- *(uint32_t*) r_tuple->addr = LOCALADDRESS_IPV4;
+ *(uint32_t*) r_tuple->addr = local_address_ipv4;
r_tuple->scopeid = (uint32_t) lo_ifi;
idx += ALIGN(sizeof(struct gaih_addrtuple));
@@ -194,31 +208,34 @@ enum nss_status _nss_myhostname_gethostbyname4_r(
}
static enum nss_status fill_in_hostent(
- const char *hn,
+ const char *canonical, const char *additional,
int af,
+ struct address *addresses, unsigned n_addresses,
+ uint32_t local_address_ipv4,
struct hostent *result,
char *buffer, size_t buflen,
int *errnop, int *h_errnop,
int32_t *ttlp,
char **canonp) {
- size_t l, idx, ms;
- char *r_addr, *r_name, *r_aliases, *r_addr_list;
+ size_t l_canonical, l_additional, idx, ms;
+ char *r_addr, *r_name, *r_aliases, *r_alias = NULL, *r_addr_list;
size_t alen;
- struct address *addresses = NULL, *a;
- unsigned n_addresses = 0, n, c;
+ struct address *a;
+ unsigned n, c;
alen = PROTO_ADDRESS_SIZE(af);
- ifconf_acquire_addresses(&addresses, &n_addresses);
-
for (a = addresses, n = 0, c = 0; n < n_addresses; a++, n++)
if (af == a->family)
c++;
- l = strlen(hn);
- ms = ALIGN(l+1)+
+ l_canonical = strlen(canonical);
+ l_additional = additional ? strlen(additional) : 0;
+ ms = ALIGN(l_canonical+1)+
+ (additional ? ALIGN(l_additional+1) : 0) +
sizeof(char*)+
+ (additional ? sizeof(char*) : 0) +
(c > 0 ? c : 1)*ALIGN(alen)+
(c > 0 ? c+1 : 2)*sizeof(char*);
@@ -229,15 +246,27 @@ static enum nss_status fill_in_hostent(
return NSS_STATUS_TRYAGAIN;
}
- /* First, fill in hostname */
+ /* First, fill in hostnames */
r_name = buffer;
- memcpy(r_name, hn, l+1);
- idx = ALIGN(l+1);
+ memcpy(r_name, canonical, l_canonical+1);
+ idx = ALIGN(l_canonical+1);
- /* Second, create (empty) aliases array */
+ if (additional) {
+ r_alias = buffer + idx;
+ memcpy(r_alias, additional, l_additional+1);
+ idx += ALIGN(l_additional+1);
+ }
+
+ /* Second, create aliases array */
r_aliases = buffer + idx;
- *(char**) r_aliases = NULL;
- idx += sizeof(char*);
+ if (additional) {
+ ((char**) r_aliases)[0] = r_alias;
+ ((char**) r_aliases)[1] = NULL;
+ idx += 2*sizeof(char*);
+ } else {
+ ((char**) r_aliases)[0] = NULL;
+ idx += sizeof(char*);
+ }
/* Third, add addresses */
r_addr = buffer + idx;
@@ -256,7 +285,7 @@ static enum nss_status fill_in_hostent(
idx += c*ALIGN(alen);
} else {
if (af == AF_INET)
- *(uint32_t*) r_addr = LOCALADDRESS_IPV4;
+ *(uint32_t*) r_addr = local_address_ipv4;
else
memcpy(r_addr, LOCALADDRESS_IPV6, 16);
@@ -316,6 +345,10 @@ enum nss_status _nss_myhostname_gethostbyname3_r(
char **canonp) {
char hn[HOST_NAME_MAX+1] = {};
+ struct address *addresses = NULL;
+ unsigned n_addresses = 0;
+ const char *canonical, *additional = NULL;
+ uint32_t local_address_ipv4;
if (af == AF_UNSPEC)
af = AF_INET;
@@ -326,19 +359,39 @@ enum nss_status _nss_myhostname_gethostbyname3_r(
return NSS_STATUS_UNAVAIL;
}
- if (gethostname(hn, sizeof(hn)-1) < 0) {
- *errnop = errno;
- *h_errnop = NO_RECOVERY;
- return NSS_STATUS_UNAVAIL;
- }
+ if (strcasecmp(name, "localhost") == 0) {
+ canonical = "localhost";
+ local_address_ipv4 = htonl(INADDR_LOOPBACK);
+ } else {
+ if (gethostname(hn, sizeof(hn)-1) < 0) {
+ *errnop = errno;
+ *h_errnop = NO_RECOVERY;
+ return NSS_STATUS_UNAVAIL;
+ }
- if (strcasecmp(name, hn) != 0) {
- *errnop = ENOENT;
- *h_errnop = HOST_NOT_FOUND;
- return NSS_STATUS_NOTFOUND;
+ if (strcasecmp(name, hn) != 0) {
+ *errnop = ENOENT;
+ *h_errnop = HOST_NOT_FOUND;
+ return NSS_STATUS_NOTFOUND;
+ }
+
+ ifconf_acquire_addresses(&addresses, &n_addresses);
+
+ canonical = hn;
+ additional = n_addresses <= 0 && af == AF_INET6 ? "localhost" : NULL;
+ local_address_ipv4 = LOCALADDRESS_IPV4;
}
- return fill_in_hostent(hn, af, host, buffer, buflen, errnop, h_errnop, ttlp, canonp);
+ return fill_in_hostent(
+ canonical, additional,
+ af,
+ addresses, n_addresses,
+ local_address_ipv4,
+ host,
+ buffer, buflen,
+ errnop, h_errnop,
+ ttlp,
+ canonp);
}
enum nss_status _nss_myhostname_gethostbyname2_r(
@@ -383,9 +436,11 @@ enum nss_status _nss_myhostname_gethostbyaddr2_r(
int32_t *ttlp) {
char hn[HOST_NAME_MAX+1] = {};
- _cleanup_free_ struct address *addresses = NULL;
+ struct address *addresses = NULL;
struct address *a;
unsigned n_addresses = 0, n;
+ uint32_t local_address_ipv4 = LOCALADDRESS_IPV4;
+ const char *canonical = NULL, *additional = NULL;
if (len != PROTO_ADDRESS_SIZE(af)) {
*errnop = EINVAL;
@@ -398,10 +453,18 @@ enum nss_status _nss_myhostname_gethostbyaddr2_r(
if ((*(uint32_t*) addr) == LOCALADDRESS_IPV4)
goto found;
+ if ((*(uint32_t*) addr) == htonl(INADDR_LOOPBACK)) {
+ canonical = "localhost";
+ local_address_ipv4 = htonl(INADDR_LOOPBACK);
+ goto found;
+ }
+
} else if (af == AF_INET6) {
- if (memcmp(addr, LOCALADDRESS_IPV6, 16) == 0)
+ if (memcmp(addr, LOCALADDRESS_IPV6, 16) == 0) {
+ additional = "localhost";
goto found;
+ }
} else {
*errnop = EAFNOSUPPORT;
@@ -422,17 +485,34 @@ enum nss_status _nss_myhostname_gethostbyaddr2_r(
*errnop = ENOENT;
*h_errnop = HOST_NOT_FOUND;
+ free(addresses);
+
return NSS_STATUS_NOTFOUND;
found:
- if (gethostname(hn, sizeof(hn)-1) < 0) {
- *errnop = errno;
- *h_errnop = NO_RECOVERY;
+ if (!canonical) {
+ if (gethostname(hn, sizeof(hn)-1) < 0) {
+ *errnop = errno;
+ *h_errnop = NO_RECOVERY;
- return NSS_STATUS_UNAVAIL;
+ free(addresses);
+
+ return NSS_STATUS_UNAVAIL;
+ }
+
+ canonical = hn;
}
- return fill_in_hostent(hn, af, host, buffer, buflen, errnop, h_errnop, ttlp, NULL);
+ return fill_in_hostent(
+ canonical, additional,
+ af,
+ addresses, n_addresses,
+ local_address_ipv4,
+ host,
+ buffer, buflen,
+ errnop, h_errnop,
+ ttlp,
+ NULL);
}
generated by cgit v1.2.3-54-g00ecf (git 2.45.2) at 2024-11-01 00:45:27 +0000