Currently this warning is triggered when compiling hv_fcopy_daemon:
hv_fcopy_daemon.c:216:4: warning: dereferencing type-punned pointer will break
strict-aliasing rules [-Wstrict-aliasing]
kernel_modver = *(__u32 *)buffer;
Convert the send/receive buffer to a union and pass individual members as
needed. This also gives the correct size for the buffer (~6K instead of 64K).
Signed-off-by: Olaf Hering <o...@aepfle.de>
---
tools/hv/hv_fcopy_daemon.c | 31 ++++++++++++++++---------------
1 file changed, 16 insertions(+), 15 deletions(-)
diff --git a/tools/hv/hv_fcopy_daemon.c b/tools/hv/hv_fcopy_daemon.c
index 26ae609a9448..c273dd34d144 100644
--- a/tools/hv/hv_fcopy_daemon.c
+++ b/tools/hv/hv_fcopy_daemon.c
@@ -138,14 +138,17 @@ void print_usage(char *argv[])
int main(int argc, char *argv[])
{
- int fcopy_fd, len;
+ int fcopy_fd;
int error;
int daemonize = 1, long_index = 0, opt;
int version = FCOPY_CURRENT_VERSION;
- char *buffer[4096 * 2];
- struct hv_fcopy_hdr *in_msg;
+ union {
+ struct hv_fcopy_hdr hdr;
+ struct hv_start_fcopy start;
+ struct hv_do_fcopy copy;
+ __u32 kernel_modver;
+ } buffer = { };
int in_handshake = 1;
- __u32 kernel_modver;
static struct option long_options[] = {
{"help", no_argument, 0, 'h' },
@@ -195,32 +198,30 @@ int main(int argc, char *argv[])
* In this loop we process fcopy messages after the
* handshake is complete.
*/
- len = pread(fcopy_fd, buffer, (4096 * 2), 0);
+ ssize_t len;
+ len = pread(fcopy_fd, &buffer, sizeof(buffer), 0);
if (len < 0) {
syslog(LOG_ERR, "pread failed: %s", strerror(errno));
exit(EXIT_FAILURE);
}
if (in_handshake) {
- if (len != sizeof(kernel_modver)) {
+ if (len != sizeof(buffer.kernel_modver)) {
syslog(LOG_ERR, "invalid version negotiation");
exit(EXIT_FAILURE);
}
- kernel_modver = *(__u32 *)buffer;
in_handshake = 0;
- syslog(LOG_INFO, "kernel module version: %d",
- kernel_modver);
+ syslog(LOG_INFO, "kernel module version: %u",
+ buffer.kernel_modver);
continue;
}
- in_msg = (struct hv_fcopy_hdr *)buffer;
-
- switch (in_msg->operation) {
+ switch (buffer.hdr.operation) {
case START_FILE_COPY:
- error = hv_start_fcopy((struct hv_start_fcopy *)in_msg);
+ error = hv_start_fcopy(&buffer.start);
break;
case WRITE_TO_FILE:
- error = hv_copy_data((struct hv_do_fcopy *)in_msg);
+ error = hv_copy_data(&buffer.copy);
break;
case COMPLETE_FCOPY:
error = hv_copy_finished();
@@ -231,7 +232,7 @@ int main(int argc, char *argv[])
default:
syslog(LOG_ERR, "Unknown operation: %d",
- in_msg->operation);
+ buffer.hdr.operation);
}
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