Annotation of embedaddon/sudo/common/term.c, revision 1.1.1.4
1.1 misho 1: /*
1.1.1.4 ! misho 2: * Copyright (c) 2011-2014 Todd C. Miller <Todd.Miller@courtesan.com>
1.1 misho 3: *
4: * Permission to use, copy, modify, and distribute this software for any
5: * purpose with or without fee is hereby granted, provided that the above
6: * copyright notice and this permission notice appear in all copies.
7: *
8: * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
9: * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10: * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
11: * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12: * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13: * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
14: * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
15: */
16:
17: #include <config.h>
18:
19: #include <sys/types.h>
20: #include <stdio.h>
21: #ifdef STDC_HEADERS
22: # include <stdlib.h>
23: # include <stddef.h>
24: #else
25: # ifdef HAVE_STDLIB_H
26: # include <stdlib.h>
27: # endif
28: #endif /* STDC_HEADERS */
29: #ifdef HAVE_STRING_H
30: # if defined(HAVE_MEMORY_H) && !defined(STDC_HEADERS)
31: # include <memory.h>
32: # endif
33: # include <string.h>
34: #endif /* HAVE_STRING_H */
35: #ifdef HAVE_STRINGS_H
36: # include <strings.h>
37: #endif /* HAVE_STRINGS_H */
1.1.1.4 ! misho 38: #include <errno.h>
! 39: #include <signal.h>
1.1 misho 40: #include <termios.h>
1.1.1.4 ! misho 41: #include <unistd.h>
1.1 misho 42:
43: #include "missing.h"
1.1.1.2 misho 44: #include "sudo_debug.h"
1.1.1.4 ! misho 45: #include "sudo_util.h"
1.1 misho 46:
47: #ifndef TCSASOFT
48: # define TCSASOFT 0
49: #endif
50: #ifndef ECHONL
51: # define ECHONL 0
52: #endif
53: #ifndef IEXTEN
54: # define IEXTEN 0
55: #endif
56: #ifndef IUCLC
57: # define IUCLC 0
58: #endif
59:
60: #ifndef _POSIX_VDISABLE
61: # ifdef VDISABLE
62: # define _POSIX_VDISABLE VDISABLE
63: # else
64: # define _POSIX_VDISABLE 0
65: # endif
66: #endif
67:
68: static struct termios term, oterm;
69: static int changed;
1.1.1.4 ! misho 70:
! 71: /* tgetpass() needs to know the erase and kill chars for cbreak mode. */
1.1 misho 72: int term_erase;
73: int term_kill;
74:
1.1.1.4 ! misho 75: static volatile sig_atomic_t got_sigttou;
! 76:
! 77: /*
! 78: * SIGTTOU signal handler for term_restore that just sets a flag.
! 79: */
! 80: static void sigttou(int signo)
! 81: {
! 82: got_sigttou = 1;
! 83: }
! 84:
! 85: /*
! 86: * Like tcsetattr() but restarts on EINTR _except_ for SIGTTOU.
! 87: * Returns 0 on success or -1 on failure, setting errno.
! 88: * Sets got_sigttou on failure if interrupted by SIGTTOU.
! 89: */
! 90: static int
! 91: tcsetattr_nobg(int fd, int flags, struct termios *tp)
! 92: {
! 93: sigaction_t sa, osa;
! 94: int rc;
! 95:
! 96: /*
! 97: * If we receive SIGTTOU from tcsetattr() it means we are
! 98: * not in the foreground process group.
! 99: * This should be less racy than using tcgetpgrp().
! 100: */
! 101: memset(&sa, 0, sizeof(sa));
! 102: sigemptyset(&sa.sa_mask);
! 103: sa.sa_handler = sigttou;
! 104: got_sigttou = 0;
! 105: sigaction(SIGTTOU, &sa, &osa);
! 106: do {
! 107: rc = tcsetattr(fd, flags, tp);
! 108: } while (rc != 0 && errno == EINTR && !got_sigttou);
! 109: sigaction(SIGTTOU, &osa, NULL);
! 110:
! 111: return rc;
! 112: }
! 113:
! 114: /*
! 115: * Restore saved terminal settings if we are in the foreground process group.
! 116: * Returns true on success or false on failure.
! 117: */
! 118: bool
! 119: term_restore(int fd, bool flush)
1.1 misho 120: {
1.1.1.2 misho 121: debug_decl(term_restore, SUDO_DEBUG_UTIL)
122:
1.1 misho 123: if (changed) {
1.1.1.4 ! misho 124: const int flags = flush ? (TCSASOFT|TCSAFLUSH) : (TCSASOFT|TCSADRAIN);
! 125: if (tcsetattr_nobg(fd, flags, &oterm) != 0)
! 126: debug_return_bool(false);
1.1 misho 127: changed = 0;
128: }
1.1.1.4 ! misho 129: debug_return_bool(true);
1.1 misho 130: }
131:
1.1.1.4 ! misho 132: /*
! 133: * Disable terminal echo.
! 134: * Returns true on success or false on failure.
! 135: */
! 136: bool
1.1 misho 137: term_noecho(int fd)
138: {
1.1.1.2 misho 139: debug_decl(term_noecho, SUDO_DEBUG_UTIL)
140:
1.1.1.4 ! misho 141: again:
1.1 misho 142: if (!changed && tcgetattr(fd, &oterm) != 0)
1.1.1.4 ! misho 143: debug_return_bool(false);
1.1 misho 144: (void) memcpy(&term, &oterm, sizeof(term));
145: CLR(term.c_lflag, ECHO|ECHONL);
146: #ifdef VSTATUS
147: term.c_cc[VSTATUS] = _POSIX_VDISABLE;
148: #endif
1.1.1.4 ! misho 149: if (tcsetattr_nobg(fd, TCSADRAIN|TCSASOFT, &term) == 0) {
1.1 misho 150: changed = 1;
1.1.1.4 ! misho 151: debug_return_bool(true);
1.1 misho 152: }
1.1.1.4 ! misho 153: if (got_sigttou) {
! 154: /* We were in the background, so oterm is probably bogus. */
! 155: kill(getpid(), SIGTTOU);
! 156: goto again;
! 157: }
! 158: debug_return_bool(false);
1.1 misho 159: }
160:
1.1.1.4 ! misho 161: /*
! 162: * Set terminal to raw mode.
! 163: * Returns true on success or false on failure.
! 164: */
! 165: bool
1.1 misho 166: term_raw(int fd, int isig)
167: {
168: struct termios term;
1.1.1.2 misho 169: debug_decl(term_raw, SUDO_DEBUG_UTIL)
1.1 misho 170:
1.1.1.4 ! misho 171: again:
1.1 misho 172: if (!changed && tcgetattr(fd, &oterm) != 0)
173: return 0;
174: (void) memcpy(&term, &oterm, sizeof(term));
175: /* Set terminal to raw mode */
176: term.c_cc[VMIN] = 1;
177: term.c_cc[VTIME] = 0;
178: CLR(term.c_iflag, ICRNL | IGNCR | INLCR | IUCLC | IXON);
179: CLR(term.c_oflag, OPOST);
180: CLR(term.c_lflag, ECHO | ICANON | ISIG | IEXTEN);
181: if (isig)
182: SET(term.c_lflag, ISIG);
1.1.1.4 ! misho 183: if (tcsetattr_nobg(fd, TCSADRAIN|TCSASOFT, &term) == 0) {
1.1 misho 184: changed = 1;
1.1.1.4 ! misho 185: debug_return_bool(true);
1.1 misho 186: }
1.1.1.4 ! misho 187: if (got_sigttou) {
! 188: /* We were in the background, so oterm is probably bogus. */
! 189: kill(getpid(), SIGTTOU);
! 190: goto again;
! 191: }
! 192: debug_return_bool(false);
1.1 misho 193: }
194:
1.1.1.4 ! misho 195: /*
! 196: * Set terminal to cbreak mode.
! 197: * Returns true on success or false on failure.
! 198: */
! 199: bool
1.1 misho 200: term_cbreak(int fd)
201: {
1.1.1.2 misho 202: debug_decl(term_cbreak, SUDO_DEBUG_UTIL)
203:
1.1.1.4 ! misho 204: again:
1.1 misho 205: if (!changed && tcgetattr(fd, &oterm) != 0)
206: return 0;
207: (void) memcpy(&term, &oterm, sizeof(term));
208: /* Set terminal to half-cooked mode */
209: term.c_cc[VMIN] = 1;
210: term.c_cc[VTIME] = 0;
1.1.1.4 ! misho 211: /* cppcheck-suppress redundantAssignment */
1.1 misho 212: CLR(term.c_lflag, ECHO | ECHONL | ICANON | IEXTEN);
1.1.1.4 ! misho 213: /* cppcheck-suppress redundantAssignment */
1.1 misho 214: SET(term.c_lflag, ISIG);
215: #ifdef VSTATUS
216: term.c_cc[VSTATUS] = _POSIX_VDISABLE;
217: #endif
1.1.1.4 ! misho 218: if (tcsetattr_nobg(fd, TCSADRAIN|TCSASOFT, &term) == 0) {
1.1 misho 219: term_erase = term.c_cc[VERASE];
220: term_kill = term.c_cc[VKILL];
221: changed = 1;
1.1.1.4 ! misho 222: debug_return_bool(true);
! 223: }
! 224: if (got_sigttou) {
! 225: /* We were in the background, so oterm is probably bogus. */
! 226: kill(getpid(), SIGTTOU);
! 227: goto again;
1.1 misho 228: }
1.1.1.4 ! misho 229: debug_return_bool(false);
1.1 misho 230: }
231:
1.1.1.4 ! misho 232: /*
! 233: * Copy terminal settings from one descriptor to another.
! 234: * Returns true on success or false on failure.
! 235: */
! 236: bool
1.1 misho 237: term_copy(int src, int dst)
238: {
239: struct termios tt;
1.1.1.2 misho 240: debug_decl(term_copy, SUDO_DEBUG_UTIL)
1.1 misho 241:
1.1.1.4 ! misho 242: again:
1.1 misho 243: if (tcgetattr(src, &tt) != 0)
1.1.1.4 ! misho 244: debug_return_bool(false);
! 245: if (tcsetattr_nobg(dst, TCSANOW|TCSASOFT, &tt) == 0)
! 246: debug_return_bool(true);
! 247: if (got_sigttou) {
! 248: /* We were in the background, so oterm is probably bogus. */
! 249: kill(getpid(), SIGTTOU);
! 250: goto again;
! 251: }
! 252: debug_return_bool(false);
1.1 misho 253: }
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