[Qemu-devel] [PATCH 06/11] chardev: add file chardev support to chardev-add (qmp)

[Gerd Hoffmann <kraxel@redhat.com>]

Add support for file chardevs.  Output file is mandatory,
input file is optional.  Both file names and file descriptor
passing is supported.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
---
 qapi-schema.json |    9 +++++-
 qemu-char.c      |   77 +++++++++++++++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 84 insertions(+), 2 deletions(-)

diff --git a/qapi-schema.json b/qapi-schema.json
index e3f0d44..8904d36 100644
--- a/qapi-schema.json
+++ b/qapi-schema.json
@@ -3030,9 +3030,16 @@
 #
 # Since: 1.4
 ##
+{ 'union': 'ChardevFileSource', 'data': { 'path' : 'str',
+                                          'fd'   : 'str' } }
+
+{ 'type': 'ChardevFile', 'data': { '*in' : 'ChardevFileSource',
+                                   'out' : 'ChardevFileSource' } }
+
 { 'type': 'ChardevDummy', 'data': { } }
 
-{ 'union': 'ChardevBackend', 'data': { 'null' : 'ChardevDummy' } }
+{ 'union': 'ChardevBackend', 'data': { 'file' : 'ChardevFile',
+                                       'null' : 'ChardevDummy' } }
 
 { 'command': 'chardev-add', 'data': {'id'      : 'str',
                                      'backend' : 'ChardevBackend' } }
diff --git a/qemu-char.c b/qemu-char.c
index c9ae8f3..91b0a57 100644
--- a/qemu-char.c
+++ b/qemu-char.c
@@ -2938,11 +2938,86 @@ CharDriverState *qemu_char_get_next_serial(void)
     return serial_hds[next_serial++];
 }
 
+#ifdef _WIN32
+
+static CharDriverState *qmp_chardev_open_file(ChardevFile *file, Error **errp)
+{
+    HANDLE out;
+
+    if (file->in) {
+        error_setg(errp, "input file not supported");
+        return NULL;
+    }
+    if (file->out->kind != CHARDEV_FILE_SOURCE_KIND_PATH) {
+        error_setg(errp, "only file paths supported");
+        return NULL;
+    }
+
+    out = CreateFile(file->out->path, GENERIC_WRITE, FILE_SHARE_READ, NULL,
+                     OPEN_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL);
+    if (out == INVALID_HANDLE_VALUE) {
+        error_setg(errp, "open %s failed", file->out->path);
+        return NULL;
+    }
+    return qemu_chr_open_win_file(out);
+}
+
+#else /* WIN32 */
+
+static int qmp_chardev_open_file_source(ChardevFileSource *src, int flags,
+                                        Error **errp)
+{
+    int fd = -1;
+
+    switch (src->kind) {
+    case CHARDEV_FILE_SOURCE_KIND_PATH:
+        TFR(fd = qemu_open(src->path, flags, 0666));
+        if (fd == -1) {
+            error_setg(errp, "open %s: %s", src->path, strerror(errno));
+        }
+        break;
+    case CHARDEV_FILE_SOURCE_KIND_FD:
+        fd = monitor_get_fd(cur_mon, src->fd, errp);
+        break;
+    default:
+        error_setg(errp, "unknown chardev file source (%d)", src->kind);
+        break;
+    }
+    return fd;
+}
+
+static CharDriverState *qmp_chardev_open_file(ChardevFile *file, Error **errp)
+{
+    int flags, in = -1, out = -1;
+
+    flags = O_WRONLY | O_TRUNC | O_CREAT | O_BINARY;
+    out = qmp_chardev_open_file_source(file->out, flags, errp);
+    if (error_is_set(errp)) {
+        return NULL;
+    }
+
+    if (file->in) {
+        flags = O_RDONLY;
+        in = qmp_chardev_open_file_source(file->in, flags, errp);
+        if (error_is_set(errp)) {
+            qemu_close(out);
+            return NULL;
+        }
+    }
+
+    return qemu_chr_open_fd(in, out);
+}
+
+#endif /* WIN32 */
+
 void qmp_chardev_add(const char *id, ChardevBackend *backend, Error **errp)
 {
     CharDriverState *chr;
 
     switch (backend->kind) {
+    case CHARDEV_BACKEND_KIND_FILE:
+        chr = qmp_chardev_open_file(backend->file, errp);
+        break;
     case CHARDEV_BACKEND_KIND_NULL:
         chr = qemu_chr_open_null(NULL);
         break;
@@ -2951,7 +3026,7 @@ void qmp_chardev_add(const char *id, ChardevBackend *backend, Error **errp)
         return;
     }
 
-    if (chr == NULL) {
+    if (chr == NULL && !error_is_set(errp)) {
         error_setg(errp, "Failed to create chardev");
     }
     if (chr) {
-- 
1.7.1