ui/qmp: move screendump to ui-qmp-cmds.c

console.c unit is over-crowded. This code is specific to the handling of
the QMP screendump command, so move it in ui-qmp-cmds.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Message-Id: <20230830093843.3531473-4-marcandre.lureau@redhat.com>

1 files changed, 187 insertions, 0 deletions

diff --git a/ui/ui-qmp-cmds.c b/ui/ui-qmp-cmds.c
index a37a7024f3..debc07d678 100644
--- a/ui/ui-qmp-cmds.c
+++ b/ui/ui-qmp-cmds.c
@@ -14,13 +14,20 @@
  */
 
 #include "qemu/osdep.h"
+
+#include "io/channel-file.h"
 #include "monitor/qmp-helpers.h"
 #include "qapi/qapi-commands-ui.h"
 #include "qapi/qmp/qerror.h"
+#include "qemu/coroutine.h"
 #include "qemu/cutils.h"
+#include "trace.h"
 #include "ui/console.h"
 #include "ui/dbus-display.h"
 #include "ui/qemu-spice.h"
+#ifdef CONFIG_PNG
+#include <png.h>
+#endif
 
 void qmp_set_password(SetPasswordOptions *opts, Error **errp)
 {
@@ -204,3 +211,183 @@ void qmp_client_migrate_info(const char *protocol, const char *hostname,
 
     error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "protocol", "'spice'");
 }
+
+#ifdef CONFIG_PNG
+/**
+ * png_save: Take a screenshot as PNG
+ *
+ * Saves screendump as a PNG file
+ *
+ * Returns true for success or false for error.
+ *
+ * @fd: File descriptor for PNG file.
+ * @image: Image data in pixman format.
+ * @errp: Pointer to an error.
+ */
+static bool png_save(int fd, pixman_image_t *image, Error **errp)
+{
+    int width = pixman_image_get_width(image);
+    int height = pixman_image_get_height(image);
+    png_struct *png_ptr;
+    png_info *info_ptr;
+    g_autoptr(pixman_image_t) linebuf =
+        qemu_pixman_linebuf_create(PIXMAN_BE_r8g8b8, width);
+    uint8_t *buf = (uint8_t *)pixman_image_get_data(linebuf);
+    FILE *f = fdopen(fd, "wb");
+    int y;
+    if (!f) {
+        error_setg_errno(errp, errno,
+                         "Failed to create file from file descriptor");
+        return false;
+    }
+
+    png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, NULL,
+                                      NULL, NULL);
+    if (!png_ptr) {
+        error_setg(errp, "PNG creation failed. Unable to write struct");
+        fclose(f);
+        return false;
+    }
+
+    info_ptr = png_create_info_struct(png_ptr);
+
+    if (!info_ptr) {
+        error_setg(errp, "PNG creation failed. Unable to write info");
+        fclose(f);
+        png_destroy_write_struct(&png_ptr, &info_ptr);
+        return false;
+    }
+
+    png_init_io(png_ptr, f);
+
+    png_set_IHDR(png_ptr, info_ptr, width, height, 8,
+                 PNG_COLOR_TYPE_RGB, PNG_INTERLACE_NONE,
+                 PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
+
+    png_write_info(png_ptr, info_ptr);
+
+    for (y = 0; y < height; ++y) {
+        qemu_pixman_linebuf_fill(linebuf, image, width, 0, y);
+        png_write_row(png_ptr, buf);
+    }
+
+    png_write_end(png_ptr, NULL);
+
+    png_destroy_write_struct(&png_ptr, &info_ptr);
+
+    if (fclose(f) != 0) {
+        error_setg_errno(errp, errno,
+                         "PNG creation failed. Unable to close file");
+        return false;
+    }
+
+    return true;
+}
+
+#else /* no png support */
+
+static bool png_save(int fd, pixman_image_t *image, Error **errp)
+{
+    error_setg(errp, "Enable PNG support with libpng for screendump");
+    return false;
+}
+
+#endif /* CONFIG_PNG */
+
+static bool ppm_save(int fd, pixman_image_t *image, Error **errp)
+{
+    int width = pixman_image_get_width(image);
+    int height = pixman_image_get_height(image);
+    g_autoptr(Object) ioc = OBJECT(qio_channel_file_new_fd(fd));
+    g_autofree char *header = NULL;
+    g_autoptr(pixman_image_t) linebuf = NULL;
+    int y;
+
+    trace_ppm_save(fd, image);
+
+    header = g_strdup_printf("P6\n%d %d\n%d\n", width, height, 255);
+    if (qio_channel_write_all(QIO_CHANNEL(ioc),
+                              header, strlen(header), errp) < 0) {
+        return false;
+    }
+
+    linebuf = qemu_pixman_linebuf_create(PIXMAN_BE_r8g8b8, width);
+    for (y = 0; y < height; y++) {
+        qemu_pixman_linebuf_fill(linebuf, image, width, 0, y);
+        if (qio_channel_write_all(QIO_CHANNEL(ioc),
+                                  (char *)pixman_image_get_data(linebuf),
+                                  pixman_image_get_stride(linebuf), errp) < 0) {
+            return false;
+        }
+    }
+
+    return true;
+}
+
+/* Safety: coroutine-only, concurrent-coroutine safe, main thread only */
+void coroutine_fn
+qmp_screendump(const char *filename, const char *device,
+               bool has_head, int64_t head,
+               bool has_format, ImageFormat format, Error **errp)
+{
+    g_autoptr(pixman_image_t) image = NULL;
+    QemuConsole *con;
+    DisplaySurface *surface;
+    int fd;
+
+    if (device) {
+        con = qemu_console_lookup_by_device_name(device, has_head ? head : 0,
+                                                 errp);
+        if (!con) {
+            return;
+        }
+    } else {
+        if (has_head) {
+            error_setg(errp, "'head' must be specified together with 'device'");
+            return;
+        }
+        con = qemu_console_lookup_by_index(0);
+        if (!con) {
+            error_setg(errp, "There is no console to take a screendump from");
+            return;
+        }
+    }
+
+    qemu_console_co_wait_update(con);
+
+    /*
+     * All pending coroutines are woken up, while the BQL is held.  No
+     * further graphic update are possible until it is released.  Take
+     * an image ref before that.
+     */
+    surface = qemu_console_surface(con);
+    if (!surface) {
+        error_setg(errp, "no surface");
+        return;
+    }
+    image = pixman_image_ref(surface->image);
+
+    fd = qemu_open_old(filename, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY, 0666);
+    if (fd == -1) {
+        error_setg(errp, "failed to open file '%s': %s", filename,
+                   strerror(errno));
+        return;
+    }
+
+    /*
+     * The image content could potentially be updated as the coroutine
+     * yields and releases the BQL. It could produce corrupted dump, but
+     * it should be otherwise safe.
+     */
+    if (has_format && format == IMAGE_FORMAT_PNG) {
+        /* PNG format specified for screendump */
+        if (!png_save(fd, image, errp)) {
+            qemu_unlink(filename);
+        }
+    } else {
+        /* PPM format specified/default for screendump */
+        if (!ppm_save(fd, image, errp)) {
+            qemu_unlink(filename);
+        }
+    }
+}