agetty: add --{erase,kill}-chars options

We need way to disable the default kill and erase agetty chars to make
the getty usable for Active Directory users with '@' in username.

It seems that the most extendible solution is to add options that
allow to complete control additional erase/kill chars. If you specify
empty strings then the chars are disabled at all.

Note that this patch is backwardly compatible.

Addresses: https://bugzilla.redhat.com/show_bug.cgi?id=870854
Signed-off-by: Karel Zak <kzak@redhat.com>

1 files changed, 28 insertions, 5 deletions

diff --git a/term-utils/agetty.c b/term-utils/agetty.c
index 152fc9106..c63dd3fde 100644
--- a/term-utils/agetty.c
+++ b/term-utils/agetty.c
@@ -144,6 +144,8 @@ struct options {
 	char *term;			/* terminal type */
 	char *initstring;		/* modem init string */
 	char *issue;			/* alternative issue file */
+	char *erasechars;		/* string with erase chars */
+	char *killchars;		/* string with kill chars */
 	int delay;			/* Sleep seconds before prompt */
 	int nice;			/* Run login with this priority */
 	int numspeed;			/* number of baud rates to try */
@@ -283,7 +285,9 @@ int main(int argc, char **argv)
 		.flags  =  F_ISSUE,		/* show /etc/issue (SYSV_STYLE) */
 		.login  =  _PATH_LOGIN,		/* default login program */
 		.tty    = "tty1",		/* default tty line */
-		.issue  =  ISSUE		/* default issue file */
+		.issue  =  ISSUE,		/* default issue file */
+		.erasechars = "#",		/* default additional erase char */
+		.killchars  = "@"		/* default additional kill char */
 	};
 	char *login_argv[LOGIN_ARGV_MAX + 1];
 	int login_argc = 0;
@@ -547,7 +551,9 @@ static void parse_args(int argc, char **argv, struct options *op)
 		NOHINTS_OPTION,
 		NOHOSTNAME_OPTION,
 		LONGHOSTNAME_OPTION,
-		HELP_OPTION
+		HELP_OPTION,
+		ERASE_CHARS_OPTION,
+		KILL_CHARS_OPTION,
 	};
 	const struct option longopts[] = {
 		{  "8bits",	     no_argument,	 0,  '8'  },
@@ -581,6 +587,8 @@ static void parse_args(int argc, char **argv, struct options *op)
 		{  "long-hostname",  no_argument,	 0,  LONGHOSTNAME_OPTION },
 		{  "version",	     no_argument,	 0,  VERSION_OPTION  },
 		{  "help",	     no_argument,	 0,  HELP_OPTION     },
+		{  "erase-chars",    required_argument,  0,  ERASE_CHARS_OPTION },
+		{  "kill-chars",     required_argument,  0,  KILL_CHARS_OPTION },
 		{ NULL, 0, 0, 0 }
 	};
 
@@ -675,6 +683,12 @@ static void parse_args(int argc, char **argv, struct options *op)
 		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);
@@ -1427,6 +1441,8 @@ static char *get_logname(struct options *op, struct termios *tp, struct chardata
 		/* Read name, watch for break and end-of-line. */
 		while (cp->eol == '\0') {
 
+			char key;
+
 			if (read(STDIN_FILENO, &c, 1) < 1) {
 
 				/* Do not report trivial like EINTR/EIO errors. */
@@ -1459,8 +1475,15 @@ static char *get_logname(struct options *op, struct termios *tp, struct chardata
 				cp->parity |= ((bits & 1) ? 1 : 2);
 			}
 
+			if (op->killchars && strchr(op->killchars, ascval))
+				key = CTL('U');
+			else if (op->erasechars && strchr(op->erasechars, ascval))
+				key = DEL;
+			else
+				key = ascval;
+
 			/* Do erase, kill and end-of-line processing. */
-			switch (ascval) {
+			switch (key) {
 			case 0:
 				*bp = 0;
 				if (op->numspeed > 1)
@@ -1473,7 +1496,6 @@ static char *get_logname(struct options *op, struct termios *tp, struct chardata
 				break;
 			case BS:
 			case DEL:
-			case '#':
 				cp->erase = ascval; /* set erase character */
 				if (bp > logname) {
 					if ((tp->c_lflag & ECHO) == 0)
@@ -1482,7 +1504,6 @@ static char *get_logname(struct options *op, struct termios *tp, struct chardata
 				}
 				break;
 			case CTL('U'):
-			case '@':
 				cp->kill = ascval;		/* set kill character */
 				while (bp > logname) {
 					if ((tp->c_lflag & ECHO) == 0)
@@ -1676,6 +1697,8 @@ static void __attribute__ ((__noreturn__)) usage(FILE * out)
 		       "     --nonewline            do not print a newline before issue\n"
 		       "     --no-hostname          no hostname at all will be shown\n"
 		       "     --long-hostname        show full qualified hostname\n"
+		       "     --erase-chars <string> additional backspace chars\n"
+		       "     --kill-chars <string>  additional kill chars\n"
 		       "     --version              output version information and exit\n"
 		       "     --help                 display this help and exit\n\n"));