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modify method of clearing terminal scroll buffer #4

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Merged
Zeno-sole merged 1 commit into from
Jun 19, 2025
+12 −58
Merged

modify method of clearing terminal scroll buffer #4

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6 changes: 6 additions & 0 deletions debian/changelog
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Original file line number Diff line number Diff line change
@@ -1,3 +1,9 @@
bash (5.2.21-2.1deepin1) unstable; urgency=medium

* modify method of clearing terminal scroll buffer

-- luojiahao <[email protected]> Thu, 19 Jun 2025 15:19:12 +0800

bash (5.2.21-2.1) unstable; urgency=medium

* Non-maintainer upload.
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64 changes: 6 additions & 58 deletions debian/clear_console.c
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Original file line number Diff line number Diff line change
Expand Up @@ -165,83 +165,31 @@ int is_pseudo_tty(int fd)
return 0;
}

int clear_console(int fd)
int clear_console()
{
int num, tmp_num;
#if defined(__linux__)
struct vt_stat vtstat;
#endif

/* Linux console secure erase (since 2.6.39), this is sufficient there;
other terminals silently ignore this code. If they don't and write junk
instead, well, we're clearing the screen anyway.
*/
write(1, "\e[3J", 4);

/* clear screen */
setupterm((char *) 0, 1, (int *) 0);
if (tputs(clear_screen, lines > 0 ? lines : 1, putch) == ERR)
{
exit(1);
}

if (is_pseudo_tty(STDIN_FILENO))
return 0;

if (!strcmp(getenv("TERM"), "screen"))
return 0;

/* get current vt */
#if defined(__linux__)
if (ioctl(fd, VT_GETSTATE, &vtstat) < 0)
#elif defined(__FreeBSD_kernel__)
if (ioctl(fd, VT_ACTIVATE, &num) < 0)
#endif
{
if (!quiet)
fprintf(stderr, "%s: cannot get VTstate\n", progname);
exit(1);
}
#if defined(__linux__)
num = vtstat.v_active;
#endif
tmp_num = (num == 6 ? 5 : 6);

/* switch vt to clear the scrollback buffer */
if (ioctl(fd, VT_ACTIVATE, tmp_num))
{
if (!quiet)
perror("chvt: VT_ACTIVATE");
exit(1);
}

if (ioctl(fd, VT_WAITACTIVE, tmp_num))
{
if (!quiet)
perror("VT_WAITACTIVE");
exit(1);
}

/* switch back */
if (ioctl(fd, VT_ACTIVATE, num))
{
if (!quiet)
perror("chvt: VT_ACTIVATE");
exit(1);
}

if (ioctl(fd, VT_WAITACTIVE, num))
/* clear screen */
setupterm((char *) 0, 1, (int *) 0);
if (tputs(clear_screen, lines > 0 ? lines : 1, putch) == ERR)
{
if (!quiet)
perror("VT_WAITACTIVE");
exit(1);
}
return 0;
}

int main (int argc, char* argv[])
{
int fd;
int result; /* option handling */
int an_option;

Expand Down Expand Up @@ -278,14 +226,14 @@ int main (int argc, char* argv[])
exit(1);
}

if ((fd = get_console_fd(NULL)) == -1)
if ((get_console_fd(NULL)) == -1)
{
if (!quiet)
fprintf(stderr, "%s: terminal is not a console\n", progname);
exit(1);
}

clear_console(fd);
clear_console();

return 0;
}
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