The default serial console can be set in the device tree
using the linux,stdout-path parameter (or equivalent from ACPI).
This is important for universal booting (EFI/EBBR) on ARM platforms
where the default console can be different (e.g ttyS0 vs ttyAMA0).
Signed-off-by: Mathew McBride <m...@traverse.com.au>
---
inittab.c | 8 ++++++++
utils/utils.c | 22 ++++++++++++++++++++++
utils/utils.h | 1 +
3 files changed, 31 insertions(+)
diff --git a/inittab.c b/inittab.c
index 45118f4..2c2270c 100644
--- a/inittab.c
+++ b/inittab.c
@@ -183,7 +183,15 @@ static void askconsole(struct init_action *a)
char line[256], *tty, *split;
int i;
+ /* First, try console= on the kernel command line,
+ * then fallback to /sys/class/tty/console/active,
+ * which should work when linux,stdout-path (or equivalent)
+ * is in the device tree
+ */
tty = get_cmdline_val("console", line, sizeof(line));
+ if (tty == NULL) {
+ tty = get_active_console(line, sizeof(line));
+ }
if (tty != NULL) {
split = strchr(tty, ',');
if (split != NULL)
diff --git a/utils/utils.c b/utils/utils.c
index 8d76129..e90feec 100644
--- a/utils/utils.c
+++ b/utils/utils.c
@@ -135,6 +135,28 @@ blobmsg_list_equal(struct blobmsg_list *l1, struct
blobmsg_list *l2)
return true;
}
+char *get_active_console(char *out, int len)
+{
+ char line[CMDLINE_SIZE + 1];
+ int fd = open("/sys/class/tty/console/active", O_RDONLY);
+ ssize_t r = read(fd, line, sizeof(line) - 1);
+
+ close(fd);
+
+ if (r <= 0)
+ return NULL;
+
+ /* The active file is terminated by a newline which we need to strip */
+ char *newline = strtok(line, "\n");
+
+ if (newline != NULL) {
+ strncpy(out, newline, len);
+ return out;
+ }
+
+ return NULL;
+}
+
char* get_cmdline_val(const char* name, char* out, int len)
{
char line[CMDLINE_SIZE + 1], *c, *sptr;
diff --git a/utils/utils.h b/utils/utils.h
index 908c314..216323e 100644
--- a/utils/utils.h
+++ b/utils/utils.h
@@ -52,6 +52,7 @@ void blobmsg_list_free(struct blobmsg_list *list);
bool blobmsg_list_equal(struct blobmsg_list *l1, struct blobmsg_list *l2);
void blobmsg_list_move(struct blobmsg_list *list, struct blobmsg_list *src);
char* get_cmdline_val(const char* name, char* out, int len);
+char *get_active_console(char *out, int len);
int patch_fd(const char *device, int fd, int flags);
int patch_stdio(const char *device);
--
2.30.0
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