File kbd-setfont-check.patch of Package kbd
From f5695d3e69ddc9670dc7dd28107327aceda1ec70 Mon Sep 17 00:00:00 2001
From: Alexey Gladkov <legion@kernel.org>
Date: Fri, 13 Mar 2026 10:38:38 +0100
Subject: [PATCH] setfont: check whether console is suitable for font
operations
Signed-off-by: Alexey Gladkov <legion@kernel.org>
---
src/include/kbd/kfont.h | 8 ++++++++
src/libkfont/kdfontop.c | 35 ++++++++++++++++++++++++++++++++---
src/libkfont/libkfont.map | 9 +++++++++
src/setfont.c | 15 +++++++++++----
4 files changed, 60 insertions(+), 7 deletions(-)
diff --git a/src/include/kbd/kfont.h b/src/include/kbd/kfont.h
index 67ad917..11bc97c 100644
--- a/src/include/kbd/kfont.h
+++ b/src/include/kbd/kfont.h
@@ -188,6 +188,14 @@ int kfont_put_font(struct kfont_context *ctx, int consolefd, unsigned char *buf,
unsigned int kfont_get_fontsize(struct kfont_context *ctx, int consolefd)
KBD_ATTR_NONNULL(1);
+/*
+ * Check whether CONSOLEFD refers to a text-mode console suitable for
+ * font operations through KDFONTOP. The check is silent and returns 1
+ * if the console can be used, 0 otherwise.
+ */
+int kfont_is_font_console(struct kfont_context *ctx, int consolefd)
+ KBD_ATTR_NONNULL(1);
+
/*
* Restore font (doesn't work).
*/
diff --git a/src/libkfont/kdfontop.c b/src/libkfont/kdfontop.c
index 4f1f0d2..64d78ad 100644
--- a/src/libkfont/kdfontop.c
+++ b/src/libkfont/kdfontop.c
@@ -21,22 +21,30 @@
#endif
static int
-is_kd_text(struct kfont_context *ctx, int fd)
+is_kd_text_mode(struct kfont_context *ctx, int fd, int report_errors)
{
unsigned int kd_mode;
if (ioctl(fd, KDGETMODE, &kd_mode)) {
- KFONT_ERR(ctx, "ioctl(KDGETMODE): %m");
+ if (report_errors)
+ KFONT_ERR(ctx, "ioctl(KDGETMODE): %m");
return 0;
}
if (kd_mode == KD_TEXT)
return 1;
- KFONT_ERR(ctx, _("Console is not in text mode"));
+ if (report_errors)
+ KFONT_ERR(ctx, _("Console is not in text mode"));
return 0;
}
+static inline int
+is_kd_text(struct kfont_context *ctx, int fd)
+{
+ return is_kd_text_mode(ctx, fd, 1);
+}
+
int
kfont_restore_font(struct kfont_context *ctx, int fd)
{
@@ -176,6 +184,27 @@ kfont_get_fontsize(struct kfont_context *ctx, int fd)
return 256;
}
+int
+kfont_is_font_console(struct kfont_context *ctx, int fd)
+{
+ if (!is_kd_text_mode(ctx, fd, 0))
+ return 0;
+
+ struct console_font_op cfo = {
+ .op = KD_FONT_OP_GET,
+ .flags = 0,
+ .width = 32,
+ .height = 32,
+ .charcount = (sizeof(unsigned char) * MAXFONTSIZE) / (64 * 128 / 8),
+ .data = NULL,
+ };
+
+ errno = 0;
+ ioctl(fd, KDFONTOP, &cfo);
+
+ return (errno != ENOSYS && errno != ENOTTY);
+}
+
static int
put_font_kdfontop(struct kfont_context *ctx, int consolefd, unsigned char *buf,
unsigned int count,
diff --git a/src/libkfont/libkfont.map b/src/libkfont/libkfont.map
index 0ea76d2..e89cd86 100644
--- a/src/libkfont/libkfont.map
+++ b/src/libkfont/libkfont.map
@@ -36,3 +36,12 @@ KFONT_1.0 {
local:
*;
};
+
+/*
+ * symbols since kbd 2.9.0
+ */
+KFONT_2.9 {
+ global:
+ kfont_is_font_console;
+
+} KFONT_1.0;
diff --git a/src/setfont.c b/src/setfont.c
index dc336c1..8a80431 100644
--- a/src/setfont.c
+++ b/src/setfont.c
@@ -166,10 +166,8 @@ int main(int argc, char *argv[])
{
const char *ifiles[MAXIFILES];
char *mfil, *ufil, *Ofil, *ofil, *omfil, *oufil, *console;
- int ifilct = 0, fd, no_m, no_u;
+ int ifilct, fd, no_m, no_u, restore, check_console, ret, c;
unsigned int iunit, hwunit;
- int restore = 0;
- int ret, c;
struct kfont_context *kfont;
@@ -183,6 +181,7 @@ int main(int argc, char *argv[])
{ "-m, --consolemap <FILE>", _("load console screen map ('none' means don't load it).") },
{ "-u, --unicodemap <FILE>", _("load font unicode map ('none' means don't load it).") },
{ "-C, --console <DEV>", _("the console device to be used.") },
+ { "-c, --check", _("check whether console is suitable for font operations.") },
{ "-d, --double", _("double size of font horizontally and vertically.") },
{ "-f, --force", _("force load unicode map.") },
{ "-R, --reset", _("reset the screen font, size, and unicode map to the bootup defaults.") },
@@ -193,6 +192,7 @@ int main(int argc, char *argv[])
};
const struct kbd_option opts[] = {
+ { "=c", "check", kbd_no_argument, 'c' },
{ "=d", "double", kbd_no_argument, 'd' },
{ "=f", "force", kbd_no_argument, 'f' },
{ "=R", "reset", kbd_no_argument, 'R' },
@@ -218,7 +218,8 @@ int main(int argc, char *argv[])
ifiles[0] = mfil = ufil = Ofil = ofil = omfil = oufil = NULL;
iunit = hwunit = 0;
- no_m = no_u = 0;
+ ifilct = no_m = no_u = 0;
+ restore = check_console = 0;
console = NULL;
while ((c = kbd_getopt(argc, argv, opts)) != -1) {
@@ -271,6 +272,9 @@ int main(int argc, char *argv[])
case 'R':
restore = 1;
break;
+ case 'c':
+ check_console = 1;
+ break;
case 'd':
kfont_set_option(kfont, kfont_double_size);
break;
@@ -316,6 +320,9 @@ int main(int argc, char *argv[])
if ((fd = getfd(console)) < 0)
kbd_error(EX_OSERR, 0, _("Couldn't get a file descriptor referring to the console."));
+ if (check_console)
+ return kfont_is_font_console(kfont, fd) ? EX_OK : EXIT_FAILURE;
+
int kd_mode = -1;
if (!ioctl(fd, KDGETMODE, &kd_mode) && (kd_mode == KD_GRAPHICS)) {
/*
--
2.51.0
