/etc/issue我想删除在登录提示内容之前插入的默认换行符tty。我正在使用agetty和systemd。
我尝试将该--nonewline选项添加到我的[email protected]：
ExecStart=/sbin/agetty --nonewline --noclear %I $TERM
结果是：
# systemctl status -l [email protected]
● [email protected] - Getty on tty5
Loaded: loaded (/usr/lib/systemd/system/[email protected]; disabled)
Active: failed (Result: start-limit) since sam. 2014-05-17 23:50:13 CEST; 56s ago
Docs: man:agetty(8)
man:systemd-getty-generator(8)
http://0pointer.de/blog/projects/serial-console.html
Process: 14538 ExecStart=/sbin/agetty --nonewline --noclear %I $TERM (code=exited, status=1/FAILURE)
Main PID: 14538 (code=exited, status=1/FAILURE)
systemd[1]: [email protected] has no holdoff time, scheduling restart.
systemd[1]: Stopping Getty on tty5...
systemd[1]: Starting Getty on tty5...
systemd[1]: [email protected] start request repeated too quickly, refusing to start.
systemd[1]: Failed to start Getty on tty5.
systemd[1]: Unit [email protected] entered failed state.
我得到：
# journalctl --no-pager -b -u [email protected]
-- Logs begin at sam. 2013-10-12 00:20:12 CEST, end at sam. 2014-05-17 23:52:49 CEST. --
systemd[1]: Starting Getty on tty5...
systemd[1]: Started Getty on tty5.
agetty[14497]: Usage:
agetty[14497]: agetty [options] <line> [<baud_rate>,...] [<termtype>]
agetty[14497]: agetty [options] <baud_rate>,... <line> [<termtype>]
agetty[14497]: Options:
agetty[14497]: -8, --8bits assume 8-bit tty
agetty[14497]: -a, --autologin <user> login the specified user automatically
agetty[14497]: -c, --noreset do not reset control mode
agetty[14497]: -E, --remote use -r <hostname> for login(1)
agetty[14497]: -f, --issue-file <file> display issue file
agetty[14497]: -h, --flow-control enable hardware flow control
agetty[14497]: -H, --host <hostname> specify login host
agetty[14497]: -i, --noissue do not display issue file
agetty[14497]: -I, --init-string <string> set init string
agetty[14497]: -l, --login-program <file> specify login program
agetty[14497]: -L, --local-line[=<mode>] control the local line flag
agetty[14497]: -m, --extract-baud extract baud rate during connect
agetty[14497]: -n, --skip-login do not prompt for login
agetty[14497]: -o, --login-options <opts> options that are passed to login
agetty[14497]: -p, --login-pause wait for any key before the login
agetty[14497]: -r, --chroot <dir> change root to the directory
agetty[14497]: -R, --hangup do virtually hangup on the tty
agetty[14497]: -s, --keep-baud try to keep baud rate after break
agetty[14497]: -t, --timeout <number> login process timeout
agetty[14497]: -U, --detect-case detect uppercase terminal
agetty[14497]: -w, --wait-cr wait carriage-return
agetty[14497]: --noclear do not clear the screen before prompt
agetty[14497]: --nohints do not print hints
agetty[14497]: --nonewline do not print a newline before issue
agetty[14497]: --nohostname no hostname at all will be shown
agetty[14497]: --long-hostname show full qualified hostname
agetty[14497]: --erase-chars <string> additional backspace chars
agetty[14497]: --kill-chars <string> additional kill chars
agetty[14497]: --help display this help and exit
agetty[14497]: --version output version information and exit
agetty[14497]: For more details see agetty(8).
systemd[1]: [email protected] has no holdoff time, scheduling restart.
systemd[1]: Stopping Getty on tty5...
为什么agetty不想识别该选项？还有另一种方法可以做到这一点吗？
答案1
你遇到了一个错误！有一个F_NONL指令永远不会在agetty 二进制文件中被调用，如源代码中所示：
...
#define F_NONL (1<<17) /* No newline before issue */
...
/* Parse command-line arguments. */
static void parse_args(int argc, char **argv, struct options *op)
{
int c;
enum {
VERSION_OPTION = CHAR_MAX + 1,
NOHINTS_OPTION,
NOHOSTNAME_OPTION,
LONGHOSTNAME_OPTION,
HELP_OPTION,
ERASE_CHARS_OPTION,
KILL_CHARS_OPTION,
};
const struct option longopts[] = {
{ "8bits", no_argument, 0, '8' },
{ "autologin", required_argument, 0, 'a' },
...
{ "skip-login", no_argument, 0, 'n' },
{ "nonewline", no_argument, 0, 'N' },
while ((c = getopt_long(argc, argv,
"8a:cC:d:Ef:hH:iI:Jl:L::mnNo:pP:r:Rst:Uw", longopts,
NULL)) != -1) {
switch (c) {
case '8':
op->flags |= F_EIGHTBITS;
break;
case 'a':
op->autolog = optarg;
break;
case 'c':
op->flags |= F_KEEPCFLAGS;
break;
case 'C':
op->chdir = optarg;
break;
case 'd':
op->delay = atoi(optarg);
break;
case 'E':
op->flags |= F_REMOTE;
break;
case 'f':
op->flags |= F_CUSTISSUE;
op->issue = optarg;
break;
case 'h':
op->flags |= F_RTSCTS;
break;
case 'H':
fakehost = optarg;
break;
case 'i':
op->flags &= ~F_ISSUE;
break;
case 'I':
init_special_char(optarg, op);
op->flags |= F_INITSTRING;
break;
case 'J':
op->flags |= F_NOCLEAR;
break;
case 'l':
op->login = optarg;
break;
case 'L':
/* -L and -L=always have the same meaning */
op->clocal = CLOCAL_MODE_ALWAYS;
if (optarg) {
if (strcmp(optarg, "=always") == 0)
op->clocal = CLOCAL_MODE_ALWAYS;
else if (strcmp(optarg, "=never") == 0)
op->clocal = CLOCAL_MODE_NEVER;
else if (strcmp(optarg, "=auto") == 0)
op->clocal = CLOCAL_MODE_AUTO;
else
log_err(_("invalid argument of --local-line"));
}
break;
case 'm':
op->flags |= F_PARSE;
break;
case 'n':
op->flags |= F_NOPROMPT;
break;
case 'o':
op->logopt = optarg;
break;
case 'p':
op->flags |= F_LOGINPAUSE;
break;
case 'P':
op->nice = atoi(optarg);
break;
case 'r':
op->chroot = optarg;
break;
case 'R':
op->flags |= F_HANGUP;
break;
case 's':
op->flags |= F_KEEPSPEED;
break;
case 't':
if ((op->timeout = atoi(optarg)) <= 0)
log_err(_("bad timeout value: %s"), optarg);
break;
case 'U':
op->flags |= F_LCUC;
break;
case 'w':
op->flags |= F_WAITCRLF;
break;
case NOHINTS_OPTION:
op->flags |= F_NOHINTS;
break;
case NOHOSTNAME_OPTION:
op->flags |= F_NOHOSTNAME;
break;
case LONGHOSTNAME_OPTION:
op->flags |= F_LONGHNAME;
break;
case ERASE_CHARS_OPTION:
op->erasechars = optarg;
break;
case KILL_CHARS_OPTION:
op->killchars = optarg;
break;
case VERSION_OPTION:
printf(_("%s from %s\n"), program_invocation_short_name,
PACKAGE_STRING);
exit(EXIT_SUCCESS);
case HELP_OPTION:
usage(stdout);
default:
usage(stderr);
}
}
在 while 循环中应该有一个像下面这样的块，但它丢失了。
case 'N':
op->flags |= F_NONL;
break;