[Qemu-devel] [PATCH 05/10] qga: guest-pipe-open for Windows guest

["Denis V. Lunev" <den@openvz.org>]

From: Olga Krishtal <okrishtal@virtuozzo.com>

The patch creates anonymous pipe that can be passed as stdin/stdout/stderr
handle to a child process spawned using forthcoming guest-file-exec
command. Working with a pipe is done using the existing guest-file-* API.

Signed-off-by: Olga Krishtal <okrishtal@virtuozzo.com>
Signed-off-by: Denis V. Lunev <den@openvz.org>
CC: Eric Blake <eblake@redhat.com>
CC: Michael Roth <mdroth@linux.vnet.ibm.com>
---
 qga/commands-win32.c | 74 +++++++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 70 insertions(+), 4 deletions(-)

diff --git a/qga/commands-win32.c b/qga/commands-win32.c
index 3db7255..b216628 100644
--- a/qga/commands-win32.c
+++ b/qga/commands-win32.c
@@ -21,6 +21,7 @@
 #include "qga-qmp-commands.h"
 #include "qapi/qmp/qerror.h"
 #include "qemu/queue.h"
+#include "qemu/sockets.h"
 
 #ifndef SHTDN_REASON_FLAG_PLANNED
 #define SHTDN_REASON_FLAG_PLANNED 0x80000000
@@ -37,6 +38,7 @@
 typedef struct GuestFileHandle {
     int64_t id;
     HANDLE fh;
+    HANDLE pipe_other_end_fd; /* if set, it's a pipe fd of the other end. */
     QTAILQ_ENTRY(GuestFileHandle) next;
 } GuestFileHandle;
 
@@ -84,7 +86,8 @@ static OpenFlags *find_open_flag(const char *mode_str)
     return NULL;
 }
 
-static int64_t guest_file_handle_add(HANDLE fh, Error **errp)
+static int64_t guest_file_handle_add(HANDLE fh, HANDLE pipe_other_end_fd,
+                                     Error **errp)
 {
     GuestFileHandle *gfh;
     int64_t handle;
@@ -96,6 +99,7 @@ static int64_t guest_file_handle_add(HANDLE fh, Error **errp)
     gfh = g_malloc0(sizeof(GuestFileHandle));
     gfh->id = handle;
     gfh->fh = fh;
+    gfh->pipe_other_end_fd = pipe_other_end_fd;
     QTAILQ_INSERT_TAIL(&guest_file_state.filehandles, gfh, next);
 
     return handle;
@@ -143,7 +147,7 @@ int64_t qmp_guest_file_open(const char *path, bool has_mode,
         return -1;
     }
 
-    fd = guest_file_handle_add(fh, errp);
+    fd = guest_file_handle_add(fh, INVALID_HANDLE_VALUE, errp);
     if (fd < 0) {
         CloseHandle(&fh);
         error_setg(errp, "failed to add handle to qmp handle table");
@@ -154,12 +158,68 @@ int64_t qmp_guest_file_open(const char *path, bool has_mode,
     return fd;
 }
 
+/* Create an anonymous pipe. To set NOWAIT mode is done via qemu_set_nonblock *
+ * will fail with ERROR_NO_DATA; WriteFile() will return 0 bytes written. */
 GuestPipeInfoList *qmp_guest_pipe_open(GuestPipeMode mode, Error **errp)
 {
-    error_set(errp, QERR_UNSUPPORTED);
+    HANDLE fd[2];
+    int this_end, other_end;
+    int64_t handle;
+    GuestPipeInfoList *pipe_list;
+    GuestPipeInfo *pipe_inf;
+    SECURITY_ATTRIBUTES sa = {
+        sizeof(SECURITY_ATTRIBUTES), NULL, 0
+    };
+
+    slog("guest-pipe-open called");
+    if (mode > 2) {
+        error_set(errp, ERROR_CLASS_GENERIC_ERROR,
+                  "Only \"r\" or \"w\" are the valid modes to open a pipe");
+        return NULL;
+    }
+
+    if (!CreatePipe(&fd[0], &fd[1], &sa, 0)) {
+        error_setg_win32(errp, GetLastError(), "CreatePipe() failed");
+        return NULL;
+    }
+
+    this_end = (mode == GUEST_PIPE_MODE_WRITE);
+    other_end = !this_end;
+
+    qemu_set_nonblock(_open_osfhandle((intptr_t)fd[this_end], O_WRONLY));
+
+    handle = guest_file_handle_add(fd[this_end], fd[other_end], errp);
+    if (handle == -1) {
+        goto fail;
+    }
+
+    slog("guest-pipe-open: handle: %" PRId64, handle);
+
+    pipe_inf = g_malloc0(sizeof(*pipe_inf));
+    pipe_inf->fd = handle;
+    pipe_list = g_malloc0(sizeof(*pipe_list));
+    pipe_list->value = pipe_inf;
+    pipe_list->next = NULL;
+    return pipe_list;
+
+fail:
+    CloseHandle(fd[0]);
+    CloseHandle(fd[1]);
     return NULL;
 }
 
+static int guest_pipe_close_other_end(GuestFileHandle *gfh)
+{
+    if (gfh->pipe_other_end_fd != INVALID_HANDLE_VALUE) {
+        if (!CloseHandle(gfh->pipe_other_end_fd)) {
+            return 1;
+        }
+        gfh->pipe_other_end_fd = INVALID_HANDLE_VALUE;
+    }
+
+    return 0;
+ }
+
 void qmp_guest_file_close(int64_t handle, Error **errp)
 {
     bool ret;
@@ -168,6 +228,12 @@ void qmp_guest_file_close(int64_t handle, Error **errp)
     if (gfh == NULL) {
         return;
     }
+
+    if (guest_pipe_close_other_end(gfh) != 0) {
+        error_setg_win32(errp, GetLastError(), "failed to close pipe handle");
+        return;
+    }
+
     ret = CloseHandle(gfh->fh);
     if (!ret) {
         error_setg_win32(errp, GetLastError(), "failed close handle");
@@ -737,7 +803,7 @@ GList *ga_command_blacklist_init(GList *blacklist)
         "guest-get-memory-blocks", "guest-set-memory-blocks",
         "guest-get-memory-block-size",
         "guest-fsfreeze-freeze-list", "guest-get-fsinfo",
-        "guest-fstrim", "guest-pipe-open", "guest-exec-status",
+        "guest-fstrim", "guest-exec-status",
         "guest-exec", NULL};
     char **p = (char **)list_unsupported;
 
-- 
1.9.1