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authorLennart Poettering <lennart@poettering.net>2011-05-20 14:37:14 +0200
committerLennart Poettering <lennart@poettering.net>2011-05-20 14:37:48 +0200
commitb83bc4e9cce2ba46371e75fe0f83af32060f0ae3 (patch)
tree5303a57d032417f6a7790250e4870b0a972e5c56
parentb136daf5ca9d1c446a3e36a1019940496f522b98 (diff)
util: use new VT ESC sequence to clear scrollback buffer
-rw-r--r--src/util.c95
1 files changed, 30 insertions, 65 deletions
diff --git a/src/util.c b/src/util.c
index 021be62547..a271708ba2 100644
--- a/src/util.c
+++ b/src/util.c
@@ -4449,16 +4449,27 @@ int terminal_vhangup(const char *name) {
int vt_disallocate(const char *name) {
int fd, r;
unsigned u;
- int temporary_vt, temporary_fd;
- char tpath[64];
- struct vt_stat vt_stat;
/* Deallocate the VT if possible. If not possible
* (i.e. because it is the active one), at least clear it
* entirely (including the scrollback buffer) */
- if (!tty_is_vc(name))
- return -EIO;
+ if (!startswith(name, "/dev/"))
+ return -EINVAL;
+
+ if (!tty_is_vc(name)) {
+ /* So this is not a VT. I guess we cannot deallocate
+ * it then. But let's at least clear the screen */
+
+ fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC);
+ if (fd < 0)
+ return fd;
+
+ loop_write(fd, "\033[H\033[2J", 7, false); /* clear screen */
+ close_nointr_nofail(fd);
+
+ return 0;
+ }
if (!startswith(name, "/dev/tty"))
return -EINVAL;
@@ -4468,79 +4479,33 @@ int vt_disallocate(const char *name) {
return r;
if (u <= 0)
- return -EIO;
+ return -EINVAL;
+ /* Try to deallocate */
fd = open_terminal("/dev/tty0", O_RDWR|O_NOCTTY|O_CLOEXEC);
if (fd < 0)
return fd;
r = ioctl(fd, VT_DISALLOCATE, u);
- if (r >= 0) {
- close_nointr_nofail(fd);
- return 0;
- }
-
- if (errno != EBUSY) {
- close_nointr_nofail(fd);
- return -errno;
- }
-
- if (ioctl(fd, VT_GETSTATE, &vt_stat) < 0) {
- close_nointr_nofail(fd);
- return -errno;
- }
+ close_nointr_nofail(fd);
- if (u != vt_stat.v_active) {
- close_nointr_nofail(fd);
- return -EBUSY;
- }
+ if (r >= 0)
+ return 0;
- if (ioctl(fd, VT_OPENQRY, &temporary_vt) < 0) {
- close_nointr_nofail(fd);
+ if (errno != EBUSY)
return -errno;
- }
-
- if (temporary_vt <= 0) {
- close_nointr_nofail(fd);
- return -EIO;
- }
- /* Switch to temporary VT */
- snprintf(tpath, sizeof(tpath), "/dev/tty%i", temporary_vt);
- char_array_0(tpath);
- temporary_fd = open_terminal(tpath, O_RDWR|O_NOCTTY|O_CLOEXEC);
- ioctl(fd, VT_ACTIVATE, temporary_vt);
- if (temporary_fd >= 0)
- close_nointr_nofail(temporary_fd);
-
- /* Reopen /dev/tty0 */
- close_nointr_nofail(fd);
- fd = open_terminal("/dev/tty0", O_RDWR|O_NOCTTY|O_CLOEXEC);
+ /* Couldn't deallocate, so let's clear it fully with
+ * scrollback */
+ fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC);
if (fd < 0)
- r = -errno;
- else {
- /* Disallocate the real VT */
- if (ioctl(fd, VT_DISALLOCATE, u) < 0)
- r = -errno;
- else
- r = 0;
- }
-
- /* Recreate original VT */
- temporary_fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC);
-
- if (temporary_fd >= 0) {
- loop_write(temporary_fd, "\033[H\033[2J", 7, false); /* clear screen explicitly */
- close_nointr_nofail(temporary_fd);
- }
+ return fd;
- /* Switch back to original VT */
- if (fd >= 0) {
- ioctl(fd, VT_ACTIVATE, vt_stat.v_active);
- close_nointr_nofail(fd);
- }
+ /* Requires Linux 2.6.40 */
+ loop_write(fd, "\033[H\033[3J", 7, false); /* clear screen including scrollback */
+ close_nointr_nofail(fd);
- return r;
+ return 0;
}
static const char *const ioprio_class_table[] = {