[libvirt] [PATCH] util: use union for sockaddr structs to avoid aliasing
From: "Daniel P. Berrange" <berrange(a)redhat.com>
Some platforms/toolchains will complain about casting
sockaddr_storage to sockaddr_un because it breaks strict
aliasing rule
../../src/util/virutil.c: In function 'virGetUNIXSocketPath':
../../src/util/virutil.c:2005: error: dereferencing pointer 'un' does break
strict-aliasing rules [-Wstrict-aliasing]
Change the code to use a union, in the same way that the
virsocketaddr.h header does.
Signed-off-by: Daniel P. Berrange <berrange(a)redhat.com>
---
Pushed as (yet another) CI build fix
src/util/virutil.c | 25 ++++++++++++++-----------
1 file changed, 14 insertions(+), 11 deletions(-)
diff --git a/src/util/virutil.c b/src/util/virutil.c
index c23fa8f92e..cd6fbf2f30 100644
--- a/src/util/virutil.c
+++ b/src/util/virutil.c
@@ -1985,30 +1985,33 @@ virGetListenFDs(void)
#ifdef HAVE_SYS_UN_H
char *virGetUNIXSocketPath(int fd)
{
- struct sockaddr_storage ss = { 0 };
- struct sockaddr_un *un = (struct sockaddr_un *)&ss;
- socklen_t len = sizeof(ss);
+ union {
+ struct sockaddr sa;
+ struct sockaddr_storage ss;
+ struct sockaddr_un un;
+ } addr = { .ss = { 0 } };
+ socklen_t len = sizeof(addr.ss);
char *path;
- if (getsockname(fd, (struct sockaddr *)&ss, &len) < 0) {
+ if (getsockname(fd, &addr.sa, &len) < 0) {
virReportSystemError(errno, _("Unable to get address of FD %d"), fd);
return NULL;
}
- if (ss.ss_family != AF_UNIX) {
+ if (addr.ss.ss_family != AF_UNIX) {
virReportSystemError(EINVAL, _("FD %d is not a UNIX socket, has
af=%d"),
- fd, ss.ss_family);
+ fd, addr.ss.ss_family);
return NULL;
}
- if (un->sun_path[0] == '\0')
- un->sun_path[0] = '@';
+ if (addr.un.sun_path[0] == '\0')
+ addr.un.sun_path[0] = '@';
- if (VIR_ALLOC_N(path, sizeof(un->sun_path) + 1) < 0)
+ if (VIR_ALLOC_N(path, sizeof(addr.un.sun_path) + 1) < 0)
return NULL;
- memcpy(path, un->sun_path, sizeof(un->sun_path));
- path[sizeof(un->sun_path)] = '\0';
+ memcpy(path, addr.un.sun_path, sizeof(addr.un.sun_path));
+ path[sizeof(addr.un.sun_path)] = '\0';
return path;
}
--
2.14.3