[libvirt] [PATCH v2 5/7] nss: Implement _nss_libvirt_gethostbyname3_r
Michal Privoznik
mprivozn at redhat.com
Thu Feb 18 14:21:05 UTC 2016
The implementation is pretty straightforward. Moreover, because
of the nature of things, gethostbyname_r and gethostbyname2_r can
be implemented at the same time too.
Signed-off-by: Michal Privoznik <mprivozn at redhat.com>
---
tools/Makefile.am | 7 +-
tools/nss/libvirt_nss.c | 354 ++++++++++++++++++++++++++++++++++++++++++++-
tools/nss/libvirt_nss.h | 14 +-
tools/nss/libvirt_nss.syms | 4 +-
4 files changed, 373 insertions(+), 6 deletions(-)
diff --git a/tools/Makefile.am b/tools/Makefile.am
index a850adb..e938e80 100644
--- a/tools/Makefile.am
+++ b/tools/Makefile.am
@@ -433,7 +433,12 @@ nss_libnss_libvirt_impl_la_CFLAGS = \
$(AM_CFLAGS) \
$(WARN_CFLAGS) \
$(PIE_CFLAGS) \
- $(COVERAGE_CFLAGS)
+ $(COVERAGE_CFLAGS) \
+ $(LIBXML_CFLAGS)
+
+nss_libnss_libvirt_impl_la_LIBADD = \
+ $(LIBXML_LIBS) \
+ ../src/libvirt.la
nss_libnss_libvirt_la_SOURCES =
nss_libnss_libvirt_la_LDFLAGS = \
diff --git a/tools/nss/libvirt_nss.c b/tools/nss/libvirt_nss.c
index 461d8ca..8a3dee3 100644
--- a/tools/nss/libvirt_nss.c
+++ b/tools/nss/libvirt_nss.c
@@ -29,8 +29,356 @@
#include "libvirt_nss.h"
-int
-blah(int c)
+#include <resolv.h>
+#include <sys/types.h>
+#include <dirent.h>
+#include <time.h>
+#include <arpa/inet.h>
+
+#include "virlease.h"
+#include "viralloc.h"
+#include "virfile.h"
+#include "virerror.h"
+#include "virstring.h"
+#include "virsocketaddr.h"
+#include "configmake.h"
+
+#if 1
+# define ERROR(...) \
+do { \
+ char ebuf[1024]; \
+ fprintf(stderr, "ERROR %s:%d : ", __FUNCTION__, __LINE__); \
+ fprintf(stderr, __VA_ARGS__); \
+ fprintf(stderr, " : %s\n", virStrerror(errno, ebuf, sizeof(ebuf))); \
+ fprintf(stderr, "\n"); \
+} while (0)
+
+# define DEBUG(...) \
+do { \
+ fprintf(stderr, "DEBUG %s:%d : ", __FUNCTION__, __LINE__); \
+ fprintf(stderr, __VA_ARGS__); \
+ fprintf(stderr, "\n"); \
+} while (0)
+#else
+# define ERROR(...) do { } while (0)
+# define DEBUG(...) do { } while (0)
+#endif
+
+#define LEASEDIR LOCALSTATEDIR "/lib/libvirt/dnsmasq/"
+
+#define ALIGN4(l) (((l) + 3) & ~3)
+#define ALIGN8(l) (((l) + 7) & ~7)
+
+#if __SIZEOF_POINTER__ == 8
+# define ALIGN(l) ALIGN8(l)
+#elif __SIZEOF_POINTER__ == 4
+# define ALIGN(l) ALIGN4(l)
+#else
+# error "Wut? Pointers are neither 4 nor 8 bytes long?"
+#endif
+
+#define FAMILY_ADDRESS_SIZE(family) ((family) == AF_INET6 ? 16 : 4)
+
+typedef struct {
+ unsigned char addr[16];
+ int af;
+} leaseAddress;
+
+/**
+ * findLease:
+ * @name: domain name to lookup
+ * @af: address family
+ * @address: all the addresses found for selected @af
+ * @naddress: number of elements in @address array
+ * @found: whether @name has been found
+ * @errnop: errno pointer
+ *
+ * Lookup @name in libvirt's IP database, parse it and store all
+ * addresses found in @address array. Callers can choose which
+ * address family (@af) should be returned. Currently only
+ * AF_INET (IPv4) and AF_INET6 (IPv6) are supported. As a corner
+ * case, AF_UNSPEC may be passed to @af in which case no address
+ * filtering is done and addresses from both families are
+ * returned.
+ *
+ * Returns -1 on error
+ * 0 on success
+ */
+static int
+findLease(const char *name,
+ int af,
+ leaseAddress **address,
+ size_t *naddress,
+ bool *found,
+ int *errnop)
{
- return c;
+ DIR *dir = NULL;
+ int ret = -1;
+ const char *leaseDir = LEASEDIR;
+ struct dirent *entry;
+ virJSONValuePtr leases_array = NULL;
+ char *server_duid = NULL;
+ ssize_t i, nleases;
+ leaseAddress *tmpAddress = NULL;
+ size_t ntmpAddress = 0;
+
+ *address = NULL;
+ *naddress = 0;
+ *found = false;
+
+ if (af != AF_UNSPEC && af != AF_INET && af != AF_INET6) {
+ errno = EAFNOSUPPORT;
+ goto cleanup;
+ }
+
+
+ if (!(dir = opendir(leaseDir))) {
+ ERROR("Failed to open dir '%s'", leaseDir);
+ goto cleanup;
+ }
+
+ if (!(leases_array = virJSONValueNewArray())) {
+ ERROR("Failed to create json array");
+ goto cleanup;
+ }
+
+ DEBUG("Dir: %s", leaseDir);
+ while ((ret = virDirRead(dir, &entry, leaseDir)) > 0) {
+ char *path;
+
+ if (entry->d_name[0] == '.')
+ continue;
+
+ if (!virFileHasSuffix(entry->d_name, ".status"))
+ continue;
+
+ if (!(path = virFileBuildPath(leaseDir, entry->d_name, NULL)))
+ goto cleanup;
+
+ DEBUG("Processing %s", path);
+
+ if (virLeaseReadCustomLeaseFile(leases_array, path, NULL, &server_duid) < 0) {
+ ERROR("Unable to parse %s", path);
+ VIR_FREE(path);
+ goto cleanup;
+ }
+
+ VIR_FREE(path);
+ }
+
+ closedir(dir);
+ dir = NULL;
+
+ nleases = virJSONValueArraySize(leases_array);
+ DEBUG("Read %zd leases", nleases);
+
+ for (i = 0; i < nleases; i++) {
+ virJSONValue const *lease;
+ const char *lease_name;
+ long long expirytime;
+ virSocketAddr sa;
+ const char *ipAddr;
+ int family;
+
+ lease = virJSONValueArrayGet(leases_array, i);
+
+ if (!lease) {
+ /* This should never happen (TM) */
+ ERROR("Unable to get element %zd of %zd", i, nleases);
+ goto cleanup;
+ }
+
+ lease_name = virJSONValueObjectGetString(lease, "hostname");
+
+ if (STRNEQ_NULLABLE(name, lease_name))
+ continue;
+
+ DEBUG("Found record for %s", lease_name);
+ *found = true;
+
+ if (virJSONValueObjectGetNumberLong(lease, "expiry-time", &expirytime) < 0) {
+ ERROR("Unable to read expiry-time on %s", lease_name);
+ goto cleanup;
+ }
+
+ /* Check whether lease has expired or not */
+ if (expirytime < (long long) time(NULL)) {
+ DEBUG("Lease for %s expired", lease_name);
+ continue;
+ }
+
+ if (!(ipAddr = virJSONValueObjectGetString(lease, "ip-address"))) {
+ ERROR("ip-address field missing for %s", name);
+ goto cleanup;
+ }
+
+ DEBUG("IP address: %s", ipAddr);
+
+ if (virSocketAddrParse(&sa, ipAddr, AF_UNSPEC) < 0) {
+ ERROR("Unable to parse %s", ipAddr);
+ goto cleanup;
+ }
+
+ family = VIR_SOCKET_ADDR_FAMILY(&sa);
+ if (af != AF_UNSPEC && af != family) {
+ DEBUG("Skipping address which family is %d, %d requested", family, af);
+ continue;
+ }
+
+ if (VIR_REALLOC_N_QUIET(tmpAddress, ntmpAddress + 1) < 0) {
+ ERROR("Out of memory");
+ goto cleanup;
+ }
+
+ tmpAddress[ntmpAddress].af = family;
+ memcpy(tmpAddress[ntmpAddress].addr,
+ (family == AF_INET ?
+ (void *) &sa.data.inet4.sin_addr.s_addr :
+ (void *) &sa.data.inet6.sin6_addr.s6_addr),
+ FAMILY_ADDRESS_SIZE(family));
+ ntmpAddress++;
+ }
+
+ *address = tmpAddress;
+ *naddress = ntmpAddress;
+ tmpAddress = NULL;
+ ntmpAddress = 0;
+
+ ret = 0;
+
+ cleanup:
+ *errnop = errno;
+ VIR_FREE(tmpAddress);
+ VIR_FREE(server_duid);
+ virJSONValueFree(leases_array);
+ if (dir)
+ closedir(dir);
+ return ret;
+}
+
+
+enum nss_status
+_nss_libvirt_gethostbyname_r(const char *name, struct hostent *result,
+ char *buffer, size_t buflen, int *errnop,
+ int *herrnop)
+{
+ int af = ((_res.options & RES_USE_INET6) ? AF_INET6 : AF_INET);
+
+ return _nss_libvirt_gethostbyname3_r(name, af, result, buffer, buflen,
+ errnop, herrnop, NULL, NULL);
+}
+
+enum nss_status
+_nss_libvirt_gethostbyname2_r(const char *name, int af, struct hostent *result,
+ char *buffer, size_t buflen, int *errnop,
+ int *herrnop)
+{
+ return _nss_libvirt_gethostbyname3_r(name, af, result, buffer, buflen,
+ errnop, herrnop, NULL, NULL);
+}
+
+enum nss_status
+_nss_libvirt_gethostbyname3_r(const char *name, int af, struct hostent *result,
+ char *buffer, size_t buflen, int *errnop,
+ int *herrnop, int32_t *ttlp, char **canonp)
+{
+ enum nss_status ret = NSS_STATUS_UNAVAIL;
+ char *r_name, *r_aliases, *r_addr, *r_addr_list;
+ leaseAddress *addr = NULL;
+ size_t naddr, i;
+ bool found = false;
+ size_t nameLen, need, idx;
+ int alen;
+ int r;
+
+ if ((r = findLease(name, af, &addr, &naddr, &found, errnop)) < 0) {
+ /* Error occurred. Return immediately. */
+ if (*errnop == EAGAIN) {
+ *herrnop = TRY_AGAIN;
+ return NSS_STATUS_TRYAGAIN;
+ } else {
+ *herrnop = NO_RECOVERY;
+ return NSS_STATUS_UNAVAIL;
+ }
+ }
+
+ if (!found) {
+ /* NOT found */
+ *errnop = ESRCH;
+ *herrnop = HOST_NOT_FOUND;
+ return NSS_STATUS_NOTFOUND;
+ } else if (!naddr) {
+ /* Found, but no data */
+ *errnop = ENXIO;
+ *herrnop = NO_DATA;
+ return NSS_STATUS_UNAVAIL;
+ }
+
+ /* Found and have data */
+
+ af = addr[0].af;
+ alen = FAMILY_ADDRESS_SIZE(af);
+
+ nameLen = strlen(name);
+ /* We need space for:
+ * a) name
+ * b) alias
+ * c) addresses
+ * d) NULL stem */
+ need = ALIGN(nameLen + 1) + naddr * ALIGN(alen) + (naddr + 2) * sizeof(char*);
+
+ if (buflen < need) {
+ *errnop = ENOMEM;
+ *herrnop = TRY_AGAIN;
+ ret = NSS_STATUS_TRYAGAIN;
+ goto cleanup;
+ }
+
+ /* First, append name */
+ r_name = buffer;
+ memcpy(r_name, name, nameLen + 1);
+ idx = ALIGN(nameLen + 1);
+
+ /* Second, create aliases array */
+ r_aliases = buffer + idx;
+ ((char**) r_aliases)[0] = NULL;
+ idx += sizeof(char*);
+
+ /* Third, append address */
+ r_addr = buffer + idx;
+ for (i = 0; i < naddr; i++)
+ memcpy(r_addr + i * ALIGN(alen), addr[i].addr, alen);
+ idx += naddr * ALIGN(alen);
+
+ /* Third, append address pointer array */
+ r_addr_list = buffer + idx;
+ for (i = 0; i < naddr; i++)
+ ((char**) r_addr_list)[i] = r_addr + i * ALIGN(alen);
+ ((char**) r_addr_list)[i] = NULL;
+ idx += (naddr + 1) * sizeof(char*);
+
+ /* At this point, idx == need */
+ DEBUG("Done idx:%zd need:%zd", idx, need);
+
+ result->h_name = r_name;
+ result->h_aliases = (char**) r_aliases;
+ result->h_addrtype = af;
+ result->h_length = alen;
+ result->h_addr_list = (char**) r_addr_list;
+
+ if (ttlp)
+ *ttlp = 0;
+
+ if (canonp)
+ *canonp = r_name;
+
+ /* Explicitly reset all error variables */
+ *errnop = 0;
+ *herrnop = NETDB_SUCCESS;
+ h_errno = 0;
+
+ ret = NSS_STATUS_SUCCESS;
+ cleanup:
+ VIR_FREE(addr);
+ return ret;
}
diff --git a/tools/nss/libvirt_nss.h b/tools/nss/libvirt_nss.h
index b54e5e3..dd037f5 100644
--- a/tools/nss/libvirt_nss.h
+++ b/tools/nss/libvirt_nss.h
@@ -32,5 +32,17 @@
# include <nss.h>
# include <netdb.h>
-int blah(int c);
+enum nss_status
+_nss_libvirt_gethostbyname_r(const char *name, struct hostent *result,
+ char *buffer, size_t buflen, int *errnop,
+ int *herrnop);
+
+enum nss_status
+_nss_libvirt_gethostbyname2_r(const char *name, int af, struct hostent *result,
+ char *buffer, size_t buflen, int *errnop,
+ int *herrnop);
+enum nss_status
+_nss_libvirt_gethostbyname3_r(const char *name, int af, struct hostent *result,
+ char *buffer, size_t buflen, int *errnop,
+ int *herrnop, int32_t *ttlp, char **canonp);
#endif /* __LIBVIRT_NSS_H__ */
diff --git a/tools/nss/libvirt_nss.syms b/tools/nss/libvirt_nss.syms
index 3246213..b88b8be 100644
--- a/tools/nss/libvirt_nss.syms
+++ b/tools/nss/libvirt_nss.syms
@@ -4,6 +4,8 @@
{
global:
- blah;
+ _nss_libvirt_gethostbyname_r;
+ _nss_libvirt_gethostbyname2_r;
+ _nss_libvirt_gethostbyname3_r;
local: *;
};
--
2.4.10
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