backend/session/freebsd: Fix the way to get TTY path

Previously, the path of TTY is generated using snprintf with %d format.
It works with TTY 1 to 10, but fails with TTY with greater number
because the number used in the name is in base 32 instead of base 10.
Since there is no standard function to convert a number to a string with
a custom base, this commit adds a function to do it.

Fixes: https://github.com/swaywm/wlroots/issues/1854
This commit is contained in:
Ting-Wei Lan 2019-12-07 22:29:20 +08:00 committed by Simon Ser
parent 01818ad2c8
commit fc6c0ca12e
1 changed files with 49 additions and 1 deletions

View File

@ -139,6 +139,51 @@ static int vt_handler(int signo, void *data) {
return 1;
}
static bool get_tty_path(int tty, char path[static 11], size_t len) {
assert(tty > 0);
const char prefix[] = "/dev/ttyv";
static_assert(sizeof(prefix) + 1 <= 11, "TTY path prefix is too long");
const size_t prefix_len = sizeof(prefix) - 1;
strcpy(path, prefix);
size_t offset = prefix_len;
const int num = tty - 1;
if (num == 0) {
path[offset++] = '0';
path[offset++] = '\0';
return true;
}
const int base = 32;
for (int remaning = num; remaning > 0; remaning /= base, offset++) {
// Return early if the buffer is too small.
if (offset + 1 >= len) {
return false;
}
const int value = remaning % base;
if (value >= 10) {
path[offset] = 'a' + value - 10;
} else {
path[offset] = '0' + value;
}
}
const size_t num_len = offset - prefix_len;
for (size_t i = 0; i < num_len / 2; i++) {
const size_t p1 = prefix_len + i;
const size_t p2 = offset - 1 - i;
const char tmp = path[p1];
path[p1] = path[p2];
path[p2] = tmp;
}
path[offset++] = '\0';
return true;
}
static bool setup_tty(struct direct_session *session, struct wl_display *display) {
int fd = -1, tty = -1, tty0_fd = -1, old_tty = 1;
if ((tty0_fd = open("/dev/ttyv0", O_RDWR | O_CLOEXEC)) < 0) {
@ -155,7 +200,10 @@ static bool setup_tty(struct direct_session *session, struct wl_display *display
}
close(tty0_fd);
char tty_path[64];
snprintf(tty_path, sizeof(tty_path), "/dev/ttyv%d", tty - 1);
if (!get_tty_path(tty, tty_path, sizeof(tty_path))) {
wlr_log(WLR_ERROR, "Could not get tty %d path", tty);
goto error;
}
wlr_log(WLR_INFO, "Using tty %s", tty_path);
fd = open(tty_path, O_RDWR | O_NOCTTY | O_CLOEXEC);