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authorOlaf Hering <olaf@aepfle.de>2017-08-10 15:45:16 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-08-16 09:16:29 -0700
commit3f2baa8a7d2efaa836f1dc4b8ee8c3ca4ba9e101 (patch)
tree6cd6821ba8f7de289eaea3b5951dbee1fcf57d78
parent3619350cf0d630d83dedd9c0d7d297da211f5ff0 (diff)
Tools: hv: update buffer handling in hv_fcopy_daemon
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. Signed-off-by: Olaf Hering <olaf@aepfle.de> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--tools/hv/hv_fcopy_daemon.c32
1 files changed, 17 insertions, 15 deletions
diff --git a/tools/hv/hv_fcopy_daemon.c b/tools/hv/hv_fcopy_daemon.c
index 26ae609a9448..457a1521f32f 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 +198,31 @@ 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 +233,7 @@ int main(int argc, char *argv[])
default:
syslog(LOG_ERR, "Unknown operation: %d",
- in_msg->operation);
+ buffer.hdr.operation);
}