Print unsent messages of failed sendmmsg syscall
* mmsghdr.c (decode_mmsgvec): Clear syserror for the time of printing
struct mmsghdr array in !use_msg_len case.
(SYS_FUNC(sendmmsg)): As failed sendmmsg syscall does not
set msg_len fields, tell this to decode_mmsgvec.
* tests/mmsg_name.c (test_mmsg_name): Check it.
diff --git a/mmsghdr.c b/mmsghdr.c
index d310a76..93e3889 100644
--- a/mmsghdr.c
+++ b/mmsghdr.c
@@ -172,6 +172,7 @@
printfd(tcp, tcp->u_arg[0]);
tprints(", ");
if (!verbose(tcp)) {
+ /* msgvec */
printaddr(tcp->u_arg[1]);
/* vlen */
tprintf(", %u, ", (unsigned int) tcp->u_arg[2]);
@@ -180,8 +181,13 @@
return RVAL_DECODED;
}
} else {
+ const unsigned int msg_len_vlen =
+ syserror(tcp) ? 0 : tcp->u_rval;
+ /* msgvec */
+ temporarily_clear_syserror(tcp);
decode_mmsgvec(tcp, tcp->u_arg[1], tcp->u_arg[2],
- tcp->u_rval, false);
+ msg_len_vlen, false);
+ restore_cleared_syserror(tcp);
/* vlen */
tprintf(", %u, ", (unsigned int) tcp->u_arg[2]);
/* flags */
@@ -199,6 +205,7 @@
save_mmsgvec_namelen(tcp, tcp->u_arg[1], tcp->u_arg[2],
sprint_timespec(tcp, tcp->u_arg[4]));
} else {
+ /* msgvec */
printaddr(tcp->u_arg[1]);
/* vlen */
tprintf(", %u, ", (unsigned int) tcp->u_arg[2]);
@@ -210,6 +217,7 @@
return 0;
} else {
if (verbose(tcp)) {
+ /* msgvec */
decode_mmsgvec(tcp, tcp->u_arg[1], tcp->u_rval,
tcp->u_rval, true);
/* vlen */
diff --git a/tests/mmsg_name.c b/tests/mmsg_name.c
index 466b602..f2b624a 100644
--- a/tests/mmsg_name.c
+++ b/tests/mmsg_name.c
@@ -30,6 +30,7 @@
#include "tests.h"
+#include <errno.h>
#include <limits.h>
#include <stddef.h>
#include <stdio.h>
@@ -54,15 +55,19 @@
const int offsetof_sun_path = offsetof(struct sockaddr_un, sun_path);
printf("{msg_name=");
- if (user_msg_namelen < offsetof_sun_path) {
+ if (!un)
+ printf("NULL");
+ else if (user_msg_namelen < offsetof_sun_path) {
printf("%p", un);
} else {
printf("{sa_family=AF_UNIX");
if (user_msg_namelen > offsetof_sun_path) {
int len = user_msg_namelen < (int) msg->msg_namelen ?
user_msg_namelen : (int) msg->msg_namelen;
- printf(", sun_path=\"%.*s\"",
- len - offsetof_sun_path, un->sun_path);
+ len -= offsetof_sun_path;
+ if (len > (int) sizeof(un->sun_path))
+ len = sizeof(un->sun_path);
+ printf(", sun_path=\"%.*s\"", len, un->sun_path);
}
printf("}");
}
@@ -78,6 +83,8 @@
static void
test_mmsg_name(const int send_fd, const int recv_fd)
{
+ struct sockaddr_un *const send_addr =
+ tail_alloc(sizeof(*send_addr) * IOV_MAX1);
char *const send_buf = tail_alloc(sizeof(*send_buf) * IOV_MAX1);
struct iovec *const send_iov = tail_alloc(sizeof(*send_iov) * IOV_MAX1);
struct mmsghdr *const send_mh = tail_alloc(sizeof(*send_mh) * IOV_MAX1);
@@ -85,6 +92,13 @@
int i, rc;
for (i = 0; i < IOV_MAX1; ++i) {
+ int sun_len = i + 1 > (int) sizeof(send_addr[i].sun_path)
+ ? (int) sizeof(send_addr[i].sun_path)
+ : i + 1;
+
+ send_addr[i].sun_family = AF_UNIX;
+ memset(send_addr[i].sun_path, 'a' + i % 26, sun_len);
+
send_buf[i] = '0' + i % 10;
send_iov[i].iov_base = &send_buf[i];
@@ -92,14 +106,57 @@
send_mh[i].msg_hdr.msg_iov = &send_iov[i];
send_mh[i].msg_hdr.msg_iovlen = 1;
- send_mh[i].msg_hdr.msg_name = 0;
- send_mh[i].msg_hdr.msg_namelen = 0;
+ send_mh[i].msg_hdr.msg_name = &send_addr[i];
+ send_mh[i].msg_hdr.msg_namelen = i + 1;
send_mh[i].msg_hdr.msg_control = 0;
send_mh[i].msg_hdr.msg_controllen = 0;
send_mh[i].msg_hdr.msg_flags = 0;
}
rc = send_mmsg(send_fd, send_mh, IOV_MAX1, MSG_DONTWAIT);
+ int saved_errno = errno;
+
+ printf("sendmmsg(%d, [", send_fd);
+ for (i = 0; i < IOV_MAX1; ++i) {
+ if (i)
+ printf(", ");
+ if (i >= IOV_MAX
+# ifndef VERBOSE_MMSGHDR
+ || i >= DEFAULT_STRLEN
+# endif
+ ) {
+ printf("...");
+ break;
+ }
+ printf("{msg_hdr=");
+ print_msghdr(&send_mh[i].msg_hdr, i + 1);
+ printf("}");
+ }
+ errno = saved_errno;
+ printf("], %u, MSG_DONTWAIT) = %d %s (%m)\n",
+ IOV_MAX1, rc, errno2name());
+
+ for (i = 0; i < IOV_MAX1; ++i) {
+ send_mh[i].msg_hdr.msg_name = 0;
+ send_mh[i].msg_hdr.msg_namelen = 0;
+ }
+
+ /*
+ * When recvmmsg is called with a valid descriptor
+ * but inaccessible memory, it causes segfaults on some architectures.
+ * As in these cases we test decoding of failed recvmmsg calls,
+ * it's ok to fail recvmmsg with any reason as long as
+ * it doesn't read that inaccessible memory.
+ */
+ rc = send_mmsg(-1, &send_mh[IOV_MAX], 2, MSG_DONTWAIT);
+ saved_errno = errno;
+ printf("sendmmsg(-1, [{msg_hdr=");
+ print_msghdr(&send_mh[IOV_MAX].msg_hdr, 0);
+ errno = saved_errno;
+ printf("}, %p], %u, MSG_DONTWAIT) = %d %s (%m)\n",
+ &send_mh[IOV_MAX1], 2, rc, errno2name());
+
+ rc = send_mmsg(send_fd, send_mh, IOV_MAX1, MSG_DONTWAIT);
if (rc < 0)
perror_msg_and_skip("sendmmsg");
@@ -115,11 +172,9 @@
printf("...");
break;
}
- printf("{msg_hdr={msg_name=NULL, msg_namelen=0"
- ", msg_iov=[{iov_base=\"%c\", iov_len=1}]"
- ", msg_iovlen=1, msg_controllen=0, msg_flags=0}%s}",
- '0' + i % 10,
- i < rc ? ", msg_len=1" : "");
+ printf("{msg_hdr=");
+ print_msghdr(&send_mh[i].msg_hdr, 0);
+ printf("%s}", i < rc ? ", msg_len=1" : "");
}
printf("], %u, MSG_DONTWAIT) = %d\n", IOV_MAX1, rc);