qemu-iotests: add unix socket help program

This program can do a sendmsg call to transfer fd with unix
socket, which is not supported in python2.

The built binary will not be deleted in clean, but it is a
existing issue in ./tests, which should be solved in another
patch.

Signed-off-by: Wenchao Xia <xiawenc@linux.vnet.ibm.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

configure

@@ -4651,7 +4651,7 @@ if [ "$dtc_internal" = "yes" ]; then
 fi
 
 # build tree in object directory in case the source is not in the current directory
-DIRS="tests tests/tcg tests/tcg/cris tests/tcg/lm32 tests/libqos tests/qapi-schema tests/tcg/xtensa"
+DIRS="tests tests/tcg tests/tcg/cris tests/tcg/lm32 tests/libqos tests/qapi-schema tests/tcg/xtensa tests/qemu-iotests"
 DIRS="$DIRS pc-bios/optionrom pc-bios/spapr-rtas pc-bios/s390-ccw"
 DIRS="$DIRS roms/seabios roms/vgabios"
 DIRS="$DIRS qapi-generated"

tests/Makefile

@@ -174,6 +174,7 @@ tests/boot-order-test$(EXESUF): tests/boot-order-test.o $(libqos-obj-y)
 tests/tmp105-test$(EXESUF): tests/tmp105-test.o $(libqos-omap-obj-y)
 tests/i440fx-test$(EXESUF): tests/i440fx-test.o $(libqos-pc-obj-y)
 tests/fw_cfg-test$(EXESUF): tests/fw_cfg-test.o $(libqos-pc-obj-y)
+tests/qemu-iotests/socket_scm_helper$(EXESUF): tests/qemu-iotests/socket_scm_helper.o
 
 # QTest rules
 
@@ -252,7 +253,7 @@ check-report.html: check-report.xml
 # Other tests
 
 .PHONY: check-tests/qemu-iotests-quick.sh
-check-tests/qemu-iotests-quick.sh: tests/qemu-iotests-quick.sh qemu-img$(EXESUF) qemu-io$(EXESUF)
+check-tests/qemu-iotests-quick.sh: tests/qemu-iotests-quick.sh qemu-img$(EXESUF) qemu-io$(EXESUF) tests/qemu-iotests/socket_scm_helper$(EXESUF)
 	$<
 
 .PHONY: check-tests/test-qapi.py

tests/qemu-iotests/socket_scm_helper.c

@@ -0,0 +1,135 @@
+/*
+ * SCM_RIGHTS with unix socket help program for test
+ *
+ * Copyright IBM, Inc. 2013
+ *
+ * Authors:
+ *  Wenchao Xia    <xiawenc@linux.vnet.ibm.com>
+ *
+ * This work is licensed under the terms of the GNU LGPL, version 2 or later.
+ * See the COPYING.LIB file in the top-level directory.
+ */
+
+#include <stdio.h>
+#include <errno.h>
+#include <sys/socket.h>
+#include <sys/un.h>
+#include <stdlib.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <unistd.h>
+
+/* #define SOCKET_SCM_DEBUG */
+
+/*
+ * @fd and @fd_to_send will not be checked for validation in this function,
+ * a blank will be sent as iov data to notify qemu.
+ */
+static int send_fd(int fd, int fd_to_send)
+{
+    struct msghdr msg;
+    struct iovec iov[1];
+    int ret;
+    char control[CMSG_SPACE(sizeof(int))];
+    struct cmsghdr *cmsg;
+
+    memset(&msg, 0, sizeof(msg));
+    memset(control, 0, sizeof(control));
+
+    /* Send a blank to notify qemu */
+    iov[0].iov_base = (void *)" ";
+    iov[0].iov_len = 1;
+
+    msg.msg_iov = iov;
+    msg.msg_iovlen = 1;
+
+    msg.msg_control = control;
+    msg.msg_controllen = sizeof(control);
+
+    cmsg = CMSG_FIRSTHDR(&msg);
+
+    cmsg->cmsg_len = CMSG_LEN(sizeof(int));
+    cmsg->cmsg_level = SOL_SOCKET;
+    cmsg->cmsg_type = SCM_RIGHTS;
+    memcpy(CMSG_DATA(cmsg), &fd, sizeof(int));
+
+    do {
+        ret = sendmsg(fd, &msg, 0);
+    } while (ret < 0 && errno == EINTR);
+
+    if (ret < 0) {
+        fprintf(stderr, "Failed to send msg, reason: %s\n", strerror(errno));
+    }
+
+    return ret;
+}
+
+/* Convert string to fd number. */
+static int get_fd_num(const char *fd_str)
+{
+    int sock;
+    char *err;
+
+    errno = 0;
+    sock = strtol(fd_str, &err, 10);
+    if (errno) {
+        fprintf(stderr, "Failed in strtol for socket fd, reason: %s\n",
+                strerror(errno));
+        return -1;
+    }
+    if (!*fd_str || *err || sock < 0) {
+        fprintf(stderr, "bad numerical value for socket fd '%s'\n", fd_str);
+        return -1;
+    }
+
+    return sock;
+}
+
+/*
+ * To make things simple, the caller needs to specify:
+ * 1. socket fd.
+ * 2. path of the file to be sent.
+ */
+int main(int argc, char **argv, char **envp)
+{
+    int sock, fd, ret;
+
+#ifdef SOCKET_SCM_DEBUG
+    int i;
+    for (i = 0; i < argc; i++) {
+        fprintf(stderr, "Parameter %d: %s\n", i, argv[i]);
+    }
+#endif
+
+    if (argc != 3) {
+        fprintf(stderr,
+                "Usage: %s < socket-fd > < file-path >\n",
+                argv[0]);
+        return EXIT_FAILURE;
+    }
+
+
+    sock = get_fd_num(argv[1]);
+    if (sock < 0) {
+        return EXIT_FAILURE;
+    }
+
+    /* Now only open a file in readonly mode for test purpose. If more precise
+       control is needed, use python script in file operation, which is
+       supposed to fork and exec this program. */
+    fd = open(argv[2], O_RDONLY);
+    if (fd < 0) {
+        fprintf(stderr, "Failed to open file '%s'\n", argv[2]);
+        return EXIT_FAILURE;
+    }
+
+    ret = send_fd(sock, fd);
+    if (ret < 0) {
+        close(fd);
+        return EXIT_FAILURE;
+    }
+
+    close(fd);
+    return EXIT_SUCCESS;
+}