From: Simon Zolin <szo...@parallels.com>
Creates a FIFO pair that can be used with existing file read/write
interfaces to communicate with processes spawned via the forthcoming
guest-file-exec interface.
Signed-off-by: Simon Zolin <szo...@parallels.com>
Acked-by: Roman Kagan <rka...@parallels.com>
Signed-off-by: Denis V. Lunev <d...@openvz.org>
CC: Michael Roth <mdr...@linux.vnet.ibm.com>
---
qga/commands-posix.c | 82 ++++++++++++++++++++++++++++++++++++++++++++++++++--
qga/commands-win32.c | 8 ++++-
qga/qapi-schema.json | 21 ++++++++++++++
3 files changed, 108 insertions(+), 3 deletions(-)
diff --git a/qga/commands-posix.c b/qga/commands-posix.c
index fd746db..bf14518 100644
--- a/qga/commands-posix.c
+++ b/qga/commands-posix.c
@@ -208,9 +208,11 @@ void qmp_guest_set_time(bool has_time, int64_t time_ns,
Error **errp)
}
}
+
typedef struct GuestFileHandle {
uint64_t id;
FILE *fh;
+ int pipe_other_end_fd; /* if set, it's a pipe fd of the other end. */
QTAILQ_ENTRY(GuestFileHandle) next;
} GuestFileHandle;
@@ -218,7 +220,8 @@ static struct {
QTAILQ_HEAD(, GuestFileHandle) filehandles;
} guest_file_state;
-static int64_t guest_file_handle_add(FILE *fh, Error **errp)
+static int64_t guest_file_handle_add(FILE *fh, int pipe_other_end_fd,
+ Error **errp)
{
GuestFileHandle *gfh;
int64_t handle;
@@ -231,6 +234,7 @@ static int64_t guest_file_handle_add(FILE *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;
@@ -422,7 +426,7 @@ int64_t qmp_guest_file_open(const char *path, bool
has_mode, const char *mode,
return -1;
}
- handle = guest_file_handle_add(fh, errp);
+ handle = guest_file_handle_add(fh, -1, errp);
if (handle < 0) {
fclose(fh);
return -1;
@@ -432,6 +436,75 @@ int64_t qmp_guest_file_open(const char *path, bool
has_mode, const char *mode,
return handle;
}
+int64_t qmp_guest_pipe_open(const char *mode, Error **err)
+{
+ FILE *f = NULL;
+ int fd[2], this_end, other_end;
+ int64_t handle;
+
+ slog("guest-pipe-open called");
+
+ if ((mode[0] != 'r' && mode[0] != 'w') || mode[1] != '\0') {
+ error_set(err, ERROR_CLASS_GENERIC_ERROR,
+ "Only \"r\" or \"w\" are the valid modes to open a pipe");
+ return -1;
+ }
+
+ if (pipe(fd) != 0) {
+ error_set_errno(err, errno, QERR_QGA_COMMAND_FAILED, "pipe() failed");
+ return -1;
+ }
+
+ this_end = (mode[0] == 'w');
+ other_end = !this_end;
+
+ if (guest_file_toggle_flags(fd[this_end], O_NONBLOCK, true, err) == -1) {
+ goto fail;
+ }
+
+ qemu_set_cloexec(fd[this_end]);
+ qemu_set_cloexec(fd[other_end]);
+
+ f = fdopen(fd[this_end], mode);
+ if (f == NULL) {
+ error_set_errno(err, errno, QERR_QGA_COMMAND_FAILED,
+ "fdopen() failed to open pipe handle");
+ goto fail;
+ }
+
+ handle = guest_file_handle_add(f, fd[other_end], err);
+ if (handle == -1) {
+ goto fail;
+ }
+
+ slog("guest-pipe-open: handle: %" PRId64, handle);
+
+ return handle;
+
+fail:
+ if (f != NULL) {
+ fclose(f);
+ } else {
+ close(fd[this_end]);
+ }
+ close(fd[other_end]);
+
+ return -1;
+}
+
+static int guest_pipe_close_other_end(GuestFileHandle *gfh)
+{
+ if (gfh->pipe_other_end_fd != -1) {
+ if (close(gfh->pipe_other_end_fd) != 0) {
+ return 1;
+ }
+
+ gfh->pipe_other_end_fd = -1;
+ }
+
+ return 0;
+}
+
void qmp_guest_file_close(int64_t handle, Error **errp)
{
GuestFileHandle *gfh = guest_file_handle_find(handle, errp);
@@ -442,6 +515,11 @@ void qmp_guest_file_close(int64_t handle, Error **errp)
return;
}
+ if (guest_pipe_close_other_end(gfh) != 0) {
+ error_setg_errno(errp, errno, "failed to close pipe handle");
+ return;
+ }
+
ret = fclose(gfh->fh);
if (ret == EOF) {
error_setg_errno(errp, errno, "failed to close handle");
diff --git a/qga/commands-win32.c b/qga/commands-win32.c
index 5db96ef..5cb7946 100644
--- a/qga/commands-win32.c
+++ b/qga/commands-win32.c
@@ -154,6 +154,12 @@ int64_t qmp_guest_file_open(const char *path, bool
has_mode,
return fd;
}
+int64_t qmp_guest_pipe_open(const char *mode, Error **errp)
+{
+ error_set(errp, QERR_UNSUPPORTED);
+ return 0;
+}
+
void qmp_guest_file_close(int64_t handle, Error **errp)
{
bool ret;
@@ -683,7 +689,7 @@ GList *ga_command_blacklist_init(GList *blacklist)
"guest-suspend-hybrid", "guest-network-get-interfaces",
"guest-get-vcpus", "guest-set-vcpus",
"guest-fsfreeze-freeze-list", "guest-get-fsinfo",
- "guest-fstrim", NULL};
+ "guest-fstrim", "guest-pipe-open", NULL};
char **p = (char **)list_unsupported;
while (*p) {
diff --git a/qga/qapi-schema.json b/qga/qapi-schema.json
index 376e79f..67d3b72 100644
--- a/qga/qapi-schema.json
+++ b/qga/qapi-schema.json
@@ -212,12 +212,33 @@
'returns': 'int' }
##
+# @guest-pipe-open
+#
+# Open a pipe to in the guest to associated with a qga-spawned processes
+# for communication.
+#
+# Returns: Guest file handle on success, as per guest-file-open. This
+# handle is useable with the same interfaces as a handle returned by
+# guest-file-open.
+#
+# Since: 2.3
+##
+{ 'command': 'guest-pipe-open',
+ 'data': { 'mode': 'str' },
+ 'returns': 'int' }
+
+##
# @guest-file-close:
#
# Close an open file in the guest
#
# @handle: filehandle returned by guest-file-open
#
+# Please note that closing the write side of a pipe will block until the read
+# side is closed. If you passed the read-side of the pipe to a qga-spawned
+# process, make sure the process has exited before attempting to close the
+# write side.
+#
# Returns: Nothing on success.
#
# Since: 0.15.0
--
1.9.1
