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getty: more simplifications; explain how we treat parity now

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function                                             old     new   delta
getty_main                                          1471    1434     -37

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko 2011-01-24 14:35:09 +01:00
parent 6596380f52
commit faaf8cb3fa
1 changed files with 93 additions and 95 deletions
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188
loginutils/getty.c
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@ -1,15 +1,23 @@
/* vi: set sw=4 ts=4: */ /* vi: set sw=4 ts=4: */
/* Based on agetty - another getty program for Linux. By W. Z. Venema 1989 /*
* Based on agetty - another getty program for Linux. By W. Z. Venema 1989
* Ported to Linux by Peter Orbaek <poe@daimi.aau.dk> * Ported to Linux by Peter Orbaek <poe@daimi.aau.dk>
* This program is freely distributable. * This program is freely distributable.
* *
* option added by Eric Rasmussen <ear@usfirst.org> - 12/28/95 * option added by Eric Rasmussen <ear@usfirst.org> - 12/28/95
* *
* 1999-02-22 Arkadiusz Mickiewicz <misiek@misiek.eu.org> * 1999-02-22 Arkadiusz Mickiewicz <misiek@misiek.eu.org>
* - added Native Language Support * - Added Native Language Support
* *
* 1999-05-05 Thorsten Kranzkowski <dl8bcu@gmx.net> * 1999-05-05 Thorsten Kranzkowski <dl8bcu@gmx.net>
* - enable hardware flow control before displaying /etc/issue * - Enabled hardware flow control before displaying /etc/issue
*
* 2011-01 Venys Vlasenko
* - Removed parity detection code. It can't work reliably:
* if all chars received have bit 7 cleared and odd (or even) parity,
* it is impossible to determine whether other side is 8-bit,no-parity
* or 7-bit,odd(even)-parity. It also interferes with non-ASCII usernames.
* - From now on, we assume that parity is correctly set.
* *
* Licensed under GPLv2 or later, see file LICENSE in this source tree. * Licensed under GPLv2 or later, see file LICENSE in this source tree.
*/ */
@ -23,13 +31,7 @@
# define IUCLC 0 # define IUCLC 0
#endif #endif
/* #ifndef LOGIN_PROCESS
* Some heuristics to find out what environment we are in: if it is not
* System V, assume it is SunOS 4.
*/
#ifdef LOGIN_PROCESS /* defined in System V utmp.h */
# include <sys/utsname.h>
#else /* if !sysV style, wtmp/utmp code is off */
# undef ENABLE_FEATURE_UTMP # undef ENABLE_FEATURE_UTMP
# undef ENABLE_FEATURE_WTMP # undef ENABLE_FEATURE_WTMP
# define ENABLE_FEATURE_UTMP 0 # define ENABLE_FEATURE_UTMP 0
@ -37,7 +39,7 @@
#endif #endif
/* The following is used for understandable diagnostics. */ /* The following is used for understandable diagnostics */
#ifdef DEBUGGING #ifdef DEBUGGING
static FILE *dbf; static FILE *dbf;
# define DEBUGTERM "/dev/ttyp0" # define DEBUGTERM "/dev/ttyp0"
@ -64,14 +66,14 @@ static FILE *dbf;
*/ */
#define ISSUE "/etc/issue" #define ISSUE "/etc/issue"
/* Some shorthands for control characters. */ /* Some shorthands for control characters */
#define CTL(x) ((x) ^ 0100) /* Assumes ASCII dialect */ #define CTL(x) ((x) ^ 0100) /* Assumes ASCII dialect */
#define CR CTL('M') /* carriage return */ #define CR CTL('M') /* carriage return */
#define NL CTL('J') /* line feed */ #define NL CTL('J') /* line feed */
#define BS CTL('H') /* back space */ #define BS CTL('H') /* back space */
#define DEL CTL('?') /* delete */ #define DEL CTL('?') /* delete */
/* Defaults for line-editing etc. characters; you may want to change this. */ /* Defaults for line-editing etc. characters; you may want to change this */
#define DEF_ERASE DEL /* default erase character */ #define DEF_ERASE DEL /* default erase character */
#define DEF_INTR CTL('C') /* default interrupt character */ #define DEF_INTR CTL('C') /* default interrupt character */
#define DEF_QUIT CTL('\\') /* default quit char */ #define DEF_QUIT CTL('\\') /* default quit char */
@ -81,23 +83,22 @@ static FILE *dbf;
#define DEF_SWITCH 0 /* default switch char */ #define DEF_SWITCH 0 /* default switch char */
/* /*
* When multiple baud rates are specified on the command line, the first one * When multiple baud rates are specified on the command line,
* we will try is the first one specified. * the first one we will try is the first one specified.
*/ */
#define MAX_SPEED 10 /* max. nr. of baud rates */ #define MAX_SPEED 10 /* max. nr. of baud rates */
struct globals { struct globals {
unsigned timeout; /* time-out period */ unsigned timeout; /* time-out period */
const char *login; /* login program */ const char *login; /* login program */
const char *fakehost;
const char *tty; /* name of tty */ const char *tty; /* name of tty */
const char *initstring; /* modem init string */ const char *initstring; /* modem init string */
const char *issue; /* alternative issue file */ const char *issue; /* alternative issue file */
int numspeed; /* number of baud rates to try */ int numspeed; /* number of baud rates to try */
int speeds[MAX_SPEED]; /* baud rates to be tried */ int speeds[MAX_SPEED]; /* baud rates to be tried */
unsigned char eol; /* end-of-line char seen (CR or NL) */
struct termios termios; /* terminal mode bits */ struct termios termios; /* terminal mode bits */
/* Storage for things detected while the login name was read. */
unsigned char erase; /* erase character */
unsigned char eol; /* end-of-line character */
char line_buf[128]; char line_buf[128];
}; };
@ -168,14 +169,14 @@ static void parse_speeds(char *arg)
} }
/* parse command-line arguments */ /* parse command-line arguments */
static void parse_args(char **argv, char **fakehost_p) static void parse_args(char **argv)
{ {
char *ts; char *ts;
int flags; int flags;
opt_complementary = "-2:t+"; /* at least 2 args; -t N */ opt_complementary = "-2:t+"; /* at least 2 args; -t N */
flags = getopt32(argv, opt_string, flags = getopt32(argv, opt_string,
&G.initstring, fakehost_p, &G.issue, &G.initstring, &G.fakehost, &G.issue,
&G.login, &G.timeout &G.login, &G.timeout
); );
if (flags & F_INITSTRING) { if (flags & F_INITSTRING) {
@ -206,17 +207,17 @@ static void parse_args(char **argv, char **fakehost_p)
/* set up tty as standard input, output, error */ /* set up tty as standard input, output, error */
static void open_tty(void) static void open_tty(void)
{ {
/* Set up new standard input, unless we are given an already opened port. */ /* Set up new standard input, unless we are given an already opened port */
if (NOT_LONE_DASH(G.tty)) { if (NOT_LONE_DASH(G.tty)) {
if (G.tty[0] != '/') if (G.tty[0] != '/')
G.tty = xasprintf("/dev/%s", G.tty); /* will leak it */ G.tty = xasprintf("/dev/%s", G.tty); /* will leak it */
/* Open the tty as standard input. */ /* Open the tty as standard input */
debug("open(2)\n"); debug("open(2)\n");
close(0); close(0);
xopen(G.tty, O_RDWR | O_NONBLOCK); /* uses fd 0 */ xopen(G.tty, O_RDWR | O_NONBLOCK); /* uses fd 0 */
/* Set proper protections and ownership. */ /* Set proper protections and ownership */
fchown(0, 0, 0); /* 0:0 */ fchown(0, 0, 0); /* 0:0 */
fchmod(0, 0620); /* crw--w---- */ fchmod(0, 0620); /* crw--w---- */
} else { } else {
@ -229,7 +230,13 @@ static void open_tty(void)
} }
} }
/* initialize termios settings */ /* We manipulate termios this way:
* - first, we read existing termios settings
* - termios_init modifies some parts and sets it
* - auto_baud and/or BREAK processing can set different speed and set termios
* - termios_final again modifies some parts and sets termios before
* execing login
*/
static void termios_init(int speed) static void termios_init(int speed)
{ {
/* Flush input and output queues, important for modems! /* Flush input and output queues, important for modems!
@ -240,7 +247,7 @@ static void termios_init(int speed)
usleep(100*1000); /* 0.1 sec */ usleep(100*1000); /* 0.1 sec */
tcflush(STDIN_FILENO, TCIOFLUSH); tcflush(STDIN_FILENO, TCIOFLUSH);
/* Set speed if it wasn't specified as "0" on command line. */ /* Set speed if it wasn't specified as "0" on command line */
if (speed != B0) if (speed != B0)
cfsetspeed(&G.termios, speed); cfsetspeed(&G.termios, speed);
@ -271,13 +278,44 @@ static void termios_init(int speed)
debug("term_io 2\n"); debug("term_io 2\n");
} }
static void termios_final(void)
{
/* General terminal-independent stuff */
G.termios.c_iflag |= IXON | IXOFF; /* 2-way flow control */
G.termios.c_lflag |= ICANON | ISIG | ECHO | ECHOE | ECHOK | ECHOKE;
/* no longer in lflag: | ECHOCTL | ECHOPRT */
G.termios.c_oflag |= OPOST;
/* G.termios.c_cflag = 0; */
G.termios.c_cc[VINTR] = DEF_INTR;
G.termios.c_cc[VQUIT] = DEF_QUIT;
G.termios.c_cc[VEOF] = DEF_EOF;
G.termios.c_cc[VEOL] = DEF_EOL;
#ifdef VSWTC
G.termios.c_cc[VSWTC] = DEF_SWITCH;
#endif
/* Account for special characters seen in input */
if (G.eol == CR) {
G.termios.c_iflag |= ICRNL; /* map CR in input to NL */
/* already done by termios_init */
/* G.termios.c_oflag |= ONLCR; map NL in output to CR-NL */
}
G.termios.c_cc[VKILL] = DEF_KILL;
#ifdef CRTSCTS
/* Optionally enable hardware flow control */
if (option_mask32 & F_RTSCTS)
G.termios.c_cflag |= CRTSCTS;
#endif
/* Finally, make the new settings effective */
if (tcsetattr_stdin_TCSANOW(&G.termios) < 0)
bb_perror_msg_and_die("tcsetattr");
}
/* extract baud rate from modem status message */ /* extract baud rate from modem status message */
static void auto_baud(void) static void auto_baud(void)
{ {
int speed;
int vmin;
unsigned iflag;
char *bp;
int nread; int nread;
/* /*
@ -296,12 +334,9 @@ static void auto_baud(void)
*/ */
/* /*
* Use 7-bit characters, don't block if input queue is empty. Errors will * Don't block if input queue is empty.
* be dealt with later on. * Errors will be dealt with later on.
*/ */
iflag = G.termios.c_iflag;
G.termios.c_iflag |= ISTRIP; /* enable 8th-bit stripping */
vmin = G.termios.c_cc[VMIN];
G.termios.c_cc[VMIN] = 0; /* don't block if queue empty */ G.termios.c_cc[VMIN] = 0; /* don't block if queue empty */
tcsetattr_stdin_TCSANOW(&G.termios); tcsetattr_stdin_TCSANOW(&G.termios);
@ -312,6 +347,8 @@ static void auto_baud(void)
sleep(1); sleep(1);
nread = safe_read(STDIN_FILENO, G.line_buf, sizeof(G.line_buf) - 1); nread = safe_read(STDIN_FILENO, G.line_buf, sizeof(G.line_buf) - 1);
if (nread > 0) { if (nread > 0) {
int speed;
char *bp;
G.line_buf[nread] = '\0'; G.line_buf[nread] = '\0';
for (bp = G.line_buf; bp < G.line_buf + nread; bp++) { for (bp = G.line_buf; bp < G.line_buf + nread; bp++) {
if (isdigit(*bp)) { if (isdigit(*bp)) {
@ -323,38 +360,38 @@ static void auto_baud(void)
} }
} }
/* Restore terminal settings. Errors will be dealt with later on. */ /* Restore terminal settings. Errors will be dealt with later on */
G.termios.c_iflag = iflag; G.termios.c_cc[VMIN] = 1; /* restore to value set by termios_init */
G.termios.c_cc[VMIN] = vmin;
tcsetattr_stdin_TCSANOW(&G.termios); tcsetattr_stdin_TCSANOW(&G.termios);
} }
/* get user name, establish parity, speed, erase, kill, eol; /* get user name, establish parity, speed, erase, kill, eol;
* return NULL on BREAK, logname on success */ * return NULL on BREAK, logname on success
*/
static char *get_logname(void) static char *get_logname(void)
{ {
char *bp; char *bp;
char c; char c;
/* Flush pending input (esp. after parsing or switching the baud rate). */ /* Flush pending input (esp. after parsing or switching the baud rate) */
usleep(100*1000); /* 0.1 sec */ usleep(100*1000); /* 0.1 sec */
tcflush(STDIN_FILENO, TCIOFLUSH); tcflush(STDIN_FILENO, TCIOFLUSH);
/* Prompt for and read a login name. */ /* Prompt for and read a login name */
G.line_buf[0] = '\0'; G.line_buf[0] = '\0';
while (!G.line_buf[0]) { while (!G.line_buf[0]) {
/* Write issue file and prompt. */ /* Write issue file and prompt */
#ifdef ISSUE #ifdef ISSUE
if (!(option_mask32 & F_NOISSUE)) if (!(option_mask32 & F_NOISSUE))
print_login_issue(G.issue, G.tty); print_login_issue(G.issue, G.tty);
#endif #endif
print_login_prompt(); print_login_prompt();
/* Read name, watch for break, parity, erase, kill, end-of-line. */ /* Read name, watch for break, parity, erase, kill, end-of-line */
bp = G.line_buf; bp = G.line_buf;
G.eol = '\0'; G.eol = '\0';
while (1) { while (1) {
/* Do not report trivial EINTR/EIO errors. */ /* Do not report trivial EINTR/EIO errors */
errno = EINTR; /* make read of 0 bytes be silent too */ errno = EINTR; /* make read of 0 bytes be silent too */
if (read(STDIN_FILENO, &c, 1) < 1) { if (read(STDIN_FILENO, &c, 1) < 1) {
if (errno == EINTR || errno == EIO) if (errno == EINTR || errno == EIO)
@ -367,7 +404,7 @@ static char *get_logname(void)
if (c == '\0' && G.numspeed > 1) if (c == '\0' && G.numspeed > 1)
return NULL; return NULL;
/* Do erase, kill and end-of-line processing. */ /* Do erase, kill and end-of-line processing */
switch (c) { switch (c) {
case CR: case CR:
case NL: case NL:
@ -376,7 +413,7 @@ static char *get_logname(void)
goto got_logname; goto got_logname;
case BS: case BS:
case DEL: case DEL:
G.erase = c; G.termios.c_cc[VERASE] = c;
if (bp > G.line_buf) { if (bp > G.line_buf) {
full_write(STDOUT_FILENO, "\010 \010", 3); full_write(STDOUT_FILENO, "\010 \010", 3);
bp--; bp--;
@ -407,61 +444,22 @@ static char *get_logname(void)
return G.line_buf; return G.line_buf;
} }
/* set the final tty mode bits */
static void termios_final(void)
{
/* General terminal-independent stuff. */
G.termios.c_iflag |= IXON | IXOFF; /* 2-way flow control */
G.termios.c_lflag |= ICANON | ISIG | ECHO | ECHOE | ECHOK | ECHOKE;
/* no longer in lflag: | ECHOCTL | ECHOPRT */
G.termios.c_oflag |= OPOST;
/* G.termios.c_cflag = 0; */
G.termios.c_cc[VINTR] = DEF_INTR; /* default interrupt */
G.termios.c_cc[VQUIT] = DEF_QUIT; /* default quit */
G.termios.c_cc[VEOF] = DEF_EOF; /* default EOF character */
G.termios.c_cc[VEOL] = DEF_EOL;
#ifdef VSWTC
G.termios.c_cc[VSWTC] = DEF_SWITCH; /* default switch character */
#endif
/* Account for special characters seen in input. */
if (G.eol == CR) {
G.termios.c_iflag |= ICRNL; /* map CR in input to NL */
G.termios.c_oflag |= ONLCR; /* map NL in output to CR-NL */
}
G.termios.c_cc[VERASE] = G.erase; /* set erase character */
G.termios.c_cc[VKILL] = DEF_KILL; /* set kill character */
#ifdef CRTSCTS
/* Optionally enable hardware flow control */
if (option_mask32 & F_RTSCTS)
G.termios.c_cflag |= CRTSCTS;
#endif
/* Finally, make the new settings effective */
if (tcsetattr_stdin_TCSANOW(&G.termios) < 0)
bb_perror_msg_and_die("tcsetattr");
}
int getty_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; int getty_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int getty_main(int argc UNUSED_PARAM, char **argv) int getty_main(int argc UNUSED_PARAM, char **argv)
{ {
int n; int n;
pid_t pid; pid_t pid;
char *fakehost = NULL; /* Fake hostname for ut_host */
char *logname; char *logname;
INIT_G(); INIT_G();
G.login = _PATH_LOGIN; /* default login program */ G.login = _PATH_LOGIN; /* default login program */
G.initstring = ""; /* modem init string */
#ifdef ISSUE #ifdef ISSUE
G.issue = ISSUE; /* default issue file */ G.issue = ISSUE; /* default issue file */
#endif #endif
G.erase = DEF_ERASE;
G.eol = CR; G.eol = CR;
/* Parse command-line arguments. */ /* Parse command-line arguments */
parse_args(argv, &fakehost); parse_args(argv);
logmode = LOGMODE_NONE; logmode = LOGMODE_NONE;
@ -524,9 +522,9 @@ int getty_main(int argc UNUSED_PARAM, char **argv)
#endif #endif
/* Update the utmp file. This tty is ours now! */ /* Update the utmp file. This tty is ours now! */
update_utmp(pid, LOGIN_PROCESS, G.tty, "LOGIN", fakehost); update_utmp(pid, LOGIN_PROCESS, G.tty, "LOGIN", G.fakehost);
/* Initialize the termios settings (raw mode, eight-bit, blocking i/o). */ /* Initialize the termios settings (raw mode, eight-bit, blocking i/o) */
debug("calling termios_init\n"); debug("calling termios_init\n");
termios_init(G.speeds[0]); termios_init(G.speeds[0]);
@ -563,30 +561,30 @@ int getty_main(int argc UNUSED_PARAM, char **argv)
int baud_index = 0; int baud_index = 0;
while (1) { while (1) {
/* Read the login name. */ /* Read the login name */
debug("reading login name\n"); debug("reading login name\n");
logname = get_logname(); logname = get_logname();
if (logname) if (logname)
break; break;
/* We are here only if G.numspeed > 1. */ /* We are here only if G.numspeed > 1 */
baud_index = (baud_index + 1) % G.numspeed; baud_index = (baud_index + 1) % G.numspeed;
cfsetspeed(&G.termios, G.speeds[baud_index]); cfsetspeed(&G.termios, G.speeds[baud_index]);
tcsetattr_stdin_TCSANOW(&G.termios); tcsetattr_stdin_TCSANOW(&G.termios);
} }
} }
/* Disable timer. */ /* Disable timer */
alarm(0); alarm(0);
/* Finalize the termios settings. */ /* Finalize the termios settings */
termios_final(); termios_final();
/* Now the newline character should be properly written. */ /* Now the newline character should be properly written */
full_write(STDOUT_FILENO, "\n", 1); full_write(STDOUT_FILENO, "\n", 1);
/* Let the login program take care of password validation. */ /* Let the login program take care of password validation */
/* We use PATH because we trust that root doesn't set "bad" PATH, /* We use PATH because we trust that root doesn't set "bad" PATH,
* and getty is not suid-root applet. */ * and getty is not suid-root applet */
/* With -n, logname == NULL, and login will ask for username instead */ /* With -n, logname == NULL, and login will ask for username instead */
BB_EXECLP(G.login, G.login, "--", logname, NULL); BB_EXECLP(G.login, G.login, "--", logname, NULL);
bb_error_msg_and_die("can't execute '%s'", G.login); bb_error_msg_and_die("can't execute '%s'", G.login);