The 'buf', 'sa' and 'hints' stack allocated helper variables are never
used together. Decrease the stack memory usage by scoping them off into
do-while blocks.
In this instance we do not want to use dynamic allocation as this is the
NSS module.
Signed-off-by: Peter Krempa <pkrempa@xxxxxxxxxx>
---
v2: Moved two error checks containing a 'continue' out of the 'do-while'
loop blocks
New pipeline:
https://gitlab.com/pipo.sk/libvirt/-/pipelines/986529301
tools/nss/libvirt_nss.c | 87 ++++++++++++++++++++++++-----------------
1 file changed, 51 insertions(+), 36 deletions(-)
diff --git a/tools/nss/libvirt_nss.c b/tools/nss/libvirt_nss.c
index 37720bf4ae..ff6ea1d373 100644
--- a/tools/nss/libvirt_nss.c
+++ b/tools/nss/libvirt_nss.c
@@ -470,58 +470,73 @@ aiforaf(const char *name,
struct addrinfo **aip)
{
struct hostent resolved;
- char buf[1024] = { 0 };
int err;
- int herr;
- struct addrinfo hints;
- struct addrinfo *res0;
- struct addrinfo *res;
char **addrList;
- if (NSS_NAME(gethostbyname2)(name, af, &resolved,
- buf, sizeof(buf),
- &err, &herr) != NS_SUCCESS)
- return;
+ /* Note: The do-while blocks in this function are used to scope off large
+ * stack allocated buffers, which are not needed at the same time */
+ do {
+ char buf[1024] = { 0 };
+ int herr;
+
+ if (NSS_NAME(gethostbyname2)(name, af, &resolved,
+ buf, sizeof(buf),
+ &err, &herr) != NS_SUCCESS)
+ return;
+ } while (false);
addrList = resolved.h_addr_list;
while (*addrList) {
- union {
- struct sockaddr sa;
- struct sockaddr_in sin;
- struct sockaddr_in6 sin6;
- } sa = { 0 };
- socklen_t salen;
void *address = *addrList;
char host[NI_MAXHOST];
+ struct addrinfo *res0;
+ struct addrinfo *res;
+
+ do {
+ union {
+ struct sockaddr sa;
+ struct sockaddr_in sin;
+ struct sockaddr_in6 sin6;
+ } sa = { 0 };
+ socklen_t salen;
+
+ if (resolved.h_addrtype == AF_INET) {
+ sa.sin.sin_family = AF_INET;
+ memcpy(&sa.sin.sin_addr.s_addr,
+ address,
+ FAMILY_ADDRESS_SIZE(AF_INET));
+ salen = sizeof(sa.sin);
+ } else {
+ sa.sin6.sin6_family = AF_INET6;
+ memcpy(&sa.sin6.sin6_addr.s6_addr,
+ address,
+ FAMILY_ADDRESS_SIZE(AF_INET6));
+ salen = sizeof(sa.sin6);
+ }
- if (resolved.h_addrtype == AF_INET) {
- sa.sin.sin_family = AF_INET;
- memcpy(&sa.sin.sin_addr.s_addr,
- address,
- FAMILY_ADDRESS_SIZE(AF_INET));
- salen = sizeof(sa.sin);
- } else {
- sa.sin6.sin6_family = AF_INET6;
- memcpy(&sa.sin6.sin6_addr.s6_addr,
- address,
- FAMILY_ADDRESS_SIZE(AF_INET6));
- salen = sizeof(sa.sin6);
- }
+ err = getnameinfo(&sa.sa, salen,
+ host, sizeof(host),
+ NULL, 0,
+ NI_NUMERICHOST | NI_NUMERICSERV);
+ } while (false);
- if ((err = getnameinfo(&sa.sa, salen,
- host, sizeof(host),
- NULL, 0,
- NI_NUMERICHOST | NI_NUMERICSERV)) != 0) {
+ if (err != 0) {
ERROR("Cannot convert socket address to string: %s",
gai_strerror(err));
continue;
}
- hints = *pai;
- hints.ai_flags = AI_NUMERICHOST;
- hints.ai_family = af;
+ do {
+ struct addrinfo hints;
+
+ hints = *pai;
+ hints.ai_flags = AI_NUMERICHOST;
+ hints.ai_family = af;
+
+ err = getaddrinfo(host, NULL, &hints, &res0);
+ } while (false);
- if (getaddrinfo(host, NULL, &hints, &res0)) {
+ if (err != 0) {
addrList++;
continue;
}
--
2.41.0
