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libvirt/tools/nss/libvirt_nss_leases.c
Ján Tomko a8d828c88b nss: convert findLeases to use json-c 
While the parsing is still done by 1K buffers, the results
are no longer filtered during the parsing, but the whole JSON
has to live in memory at once, which was also the case before
the NSS plugin dropped its dependency on libvirt_util.

Also, the new parser might be more forgiving of missing elements.

Signed-off-by: Ján Tomko <jtomko@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
2024-09-24 08:24:00 +02:00

314 lines
8.3 KiB
C
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/*
* libvirt_nss_leases.c: Name Service Switch plugin lease file parser
*
* Copyright (C) 2019 Red Hat, Inc.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library. If not, see
* <http://www.gnu.org/licenses/>.
*/
#include <config.h>
#include <unistd.h>
#include <string.h>
#include <stdlib.h>
#include <stdbool.h>
#include <fcntl.h>
#include <json.h>
#include "libvirt_nss_leases.h"
#include "libvirt_nss.h"
static int
appendAddr(const char *name __attribute__((unused)),
leaseAddress **tmpAddress,
size_t *ntmpAddress,
const char *ipAddr,
long long expirytime,
int af)
{
int family;
size_t i;
struct addrinfo hints = {0};
struct addrinfo *res = NULL;
union {
struct sockaddr sa;
struct sockaddr_in sin;
struct sockaddr_in6 sin6;
} sa;
unsigned char addr[16];
int err;
leaseAddress *newAddr;
DEBUG("IP address: %s", ipAddr);
hints.ai_family = AF_UNSPEC;
hints.ai_flags = AI_NUMERICHOST;
if ((err = getaddrinfo(ipAddr, NULL, &hints, &res)) != 0) {
ERROR("Cannot parse socket address '%s': %s",
ipAddr, gai_strerror(err));
return -1;
}
if (!res) {
ERROR("No resolved address for '%s'", ipAddr);
return -1;
}
family = res->ai_family;
memcpy(&sa, res->ai_addr, res->ai_addrlen);
freeaddrinfo(res);
if (family == AF_INET) {
memcpy(addr, &sa.sin.sin_addr, sizeof(sa.sin.sin_addr));
} else if (family == AF_INET6) {
memcpy(addr, &sa.sin6.sin6_addr, sizeof(sa.sin6.sin6_addr));
} else {
DEBUG("Skipping unexpected family %d", family);
return 0;
}
if (af != AF_UNSPEC && af != family) {
DEBUG("Skipping address which family is %d, %d requested", family, af);
return 0;
}
for (i = 0; i < *ntmpAddress; i++) {
if (family == AF_INET) {
if ((*tmpAddress)[i].af == AF_INET &&
memcmp((*tmpAddress)[i].addr,
&sa.sin.sin_addr,
sizeof(sa.sin.sin_addr)) == 0) {
DEBUG("IP address already in the list");
return 0;
}
} else {
if ((*tmpAddress)[i].af == AF_INET6 &&
memcmp((*tmpAddress)[i].addr,
&sa.sin6.sin6_addr,
sizeof(sa.sin6.sin6_addr)) == 0) {
DEBUG("IP address already in the list");
return 0;
}
}
}
newAddr = realloc(*tmpAddress, sizeof(*newAddr) * (*ntmpAddress + 1));
if (!newAddr) {
ERROR("Out of memory");
return -1;
}
*tmpAddress = newAddr;
(*tmpAddress)[*ntmpAddress].expirytime = expirytime;
(*tmpAddress)[*ntmpAddress].af = family;
if (family == AF_INET)
memcpy((*tmpAddress)[*ntmpAddress].addr,
&sa.sin.sin_addr,
sizeof(sa.sin.sin_addr));
else
memcpy((*tmpAddress)[*ntmpAddress].addr,
&sa.sin6.sin6_addr,
sizeof(sa.sin6.sin6_addr));
(*ntmpAddress)++;
return 0;
}
/**
* findLeaseInJSON
*
* @jobj: the json object containing the leases
* @name: the requested hostname (optional if a MAC address is present)
* @macs: the array of MAC addresses we're matching (optional if we have a hostname)
* @nmacs: the size of the MAC array
* @af: the requested address family
* @now: current time (to eliminate expired leases)
* @addrs: the returned matching addresses
* @naddrs: size of the returned array
* @found: whether a match was found
*
* Returns 0 even if nothing was found
* -1 on error
*/
static int
findLeaseInJSON(json_object *jobj,
const char *name,
char **macs,
size_t nmacs,
int af,
time_t now,
leaseAddress **addrs,
size_t *naddrs,
bool *found)
{
size_t i;
int len;
if (!json_object_is_type(jobj, json_type_array)) {
ERROR("parsed JSON does not contain the leases array");
return -1;
}
len = json_object_array_length(jobj);
for (i = 0; i < len; i++) {
json_object *lease = NULL;
json_object *expiry = NULL;
json_object *ipobj = NULL;
unsigned long long expiryTime;
const char *ipaddr;
lease = json_object_array_get_idx(jobj, i);
if (macs) {
const char *macAddr;
bool match = false;
json_object *val;
size_t j;
val = json_object_object_get(lease, "mac-address");
if (!val)
continue;
macAddr = json_object_get_string(val);
if (!macAddr)
continue;
for (j = 0; j < nmacs; j++) {
if (strcmp(macs[j], macAddr) == 0) {
match = true;
break;
}
}
if (!match)
continue;
} else {
const char *leaseName;
json_object *val;
val = json_object_object_get(lease, "hostname");
if (!val)
continue;
leaseName = json_object_get_string(val);
if (!leaseName)
continue;
if (strcasecmp(leaseName, name) != 0)
continue;
}
expiry = json_object_object_get(lease, "expiry-time");
if (!expiry) {
ERROR("Missing expiry time for %s", name);
return -1;
}
expiryTime = json_object_get_uint64(expiry);
if (expiryTime > 0 && expiryTime < now) {
DEBUG("Skipping expired lease for %s", name);
continue;
}
ipobj = json_object_object_get(lease, "ip-address");
if (!ipobj) {
DEBUG("Missing IP address for %s", name);
continue;
}
ipaddr = json_object_get_string(ipobj);
DEBUG("Found record for %s", name);
*found = true;
if (appendAddr(name,
addrs, naddrs,
ipaddr,
expiryTime,
af) < 0)
return -1;
}
return 0;
}
int
findLeases(const char *file,
const char *name,
char **macs,
size_t nmacs,
int af,
time_t now,
leaseAddress **addrs,
size_t *naddrs,
bool *found)
{
int fd = -1;
int ret = -1;
json_object *jobj = NULL;
json_tokener *tok = NULL;
enum json_tokener_error jerr;
int jsonflags = JSON_TOKENER_STRICT | JSON_TOKENER_VALIDATE_UTF8;
char line[1024];
ssize_t nreadTotal = 0;
int rv;
if ((fd = open(file, O_RDONLY)) < 0) {
ERROR("Cannot open %s", file);
goto cleanup;
}
tok = json_tokener_new();
json_tokener_set_flags(tok, jsonflags);
do {
rv = read(fd, line, sizeof(line));
if (rv < 0)
goto cleanup;
if (rv == 0)
break;
nreadTotal += rv;
jobj = json_tokener_parse_ex(tok, line, rv);
jerr = json_tokener_get_error(tok);
} while (jerr == json_tokener_continue);
if (jerr == json_tokener_continue) {
ERROR("Cannot parse %s: incomplete json found", file);
goto cleanup;
}
if (nreadTotal > 0 && jerr != json_tokener_success) {
ERROR("Cannot parse %s: %s", file, json_tokener_error_desc(jerr));
goto cleanup;
}
ret = findLeaseInJSON(jobj, name, macs, nmacs, af, now,
addrs, naddrs, found);
cleanup:
json_object_put(jobj);
json_tokener_free(tok);
if (ret != 0) {
free(*addrs);
*addrs = NULL;
*naddrs = 0;
}
if (fd != -1)
close(fd);
return ret;
}
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