Annotation of embedaddon/sudo/src/exec_pty.c, revision 1.1.1.2
1.1 misho 1: /*
2: * Copyright (c) 2009-2011 Todd C. Miller <Todd.Miller@courtesan.com>
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 <sys/param.h>
21: #ifdef HAVE_SYS_SYSMACROS_H
22: # include <sys/sysmacros.h>
23: #endif
24: #include <sys/socket.h>
25: #include <sys/time.h>
26: #include <sys/wait.h>
27: #include <sys/ioctl.h>
28: #ifdef HAVE_SYS_SELECT_H
29: # include <sys/select.h>
30: #endif /* HAVE_SYS_SELECT_H */
31: #include <stdio.h>
32: #ifdef STDC_HEADERS
33: # include <stdlib.h>
34: # include <stddef.h>
35: #else
36: # ifdef HAVE_STDLIB_H
37: # include <stdlib.h>
38: # endif
39: #endif /* STDC_HEADERS */
40: #ifdef HAVE_STRING_H
41: # if defined(HAVE_MEMORY_H) && !defined(STDC_HEADERS)
42: # include <memory.h>
43: # endif
44: # include <string.h>
45: #endif /* HAVE_STRING_H */
46: #ifdef HAVE_STRINGS_H
47: # include <strings.h>
48: #endif /* HAVE_STRINGS_H */
49: #ifdef HAVE_UNISTD_H
50: # include <unistd.h>
51: #endif /* HAVE_UNISTD_H */
52: #if TIME_WITH_SYS_TIME
53: # include <time.h>
54: #endif
55: #include <errno.h>
56: #include <fcntl.h>
57: #include <signal.h>
58: #include <termios.h>
59:
60: #include "sudo.h"
61: #include "sudo_exec.h"
62: #include "sudo_plugin.h"
63: #include "sudo_plugin_int.h"
64:
65: #define SFD_STDIN 0
66: #define SFD_STDOUT 1
67: #define SFD_STDERR 2
68: #define SFD_MASTER 3
69: #define SFD_SLAVE 4
70: #define SFD_USERTTY 5
71:
72: #define TERM_COOKED 0
73: #define TERM_RAW 1
74:
75: /* Compatibility with older tty systems. */
76: #if !defined(TIOCGWINSZ) && defined(TIOCGSIZE)
77: # define TIOCGWINSZ TIOCGSIZE
78: # define TIOCSWINSZ TIOCSSIZE
79: # define winsize ttysize
80: #endif
81:
82: struct io_buffer {
83: struct io_buffer *next;
84: int len; /* buffer length (how much produced) */
85: int off; /* write position (how much already consumed) */
86: int rfd; /* reader (producer) */
87: int wfd; /* writer (consumer) */
1.1.1.2 ! misho 88: bool (*action)(const char *buf, unsigned int len);
1.1 misho 89: char buf[16 * 1024];
90: };
91:
92: static char slavename[PATH_MAX];
1.1.1.2 ! misho 93: static bool foreground, pipeline, tty_initialized;
1.1 misho 94: static int io_fds[6] = { -1, -1, -1, -1, -1, -1};
95: static int ttymode = TERM_COOKED;
96: static pid_t ppgrp, child, child_pgrp;
97: static sigset_t ttyblock;
98: static struct io_buffer *iobufs;
99:
100: static void flush_output(void);
101: static int exec_monitor(struct command_details *details, int backchannel);
1.1.1.2 ! misho 102: static void exec_pty(struct command_details *detail, int *errfd);
1.1 misho 103: static void sigwinch(int s);
104: static void sync_ttysize(int src, int dst);
1.1.1.2 ! misho 105: static void deliver_signal(pid_t pid, int signo, bool from_parent);
1.1 misho 106: static int safe_close(int fd);
1.1.1.2 ! misho 107: static void check_foreground(void);
1.1 misho 108:
109: /*
110: * Cleanup hook for error()/errorx()
111: */
112: void
113: cleanup(int gotsignal)
114: {
1.1.1.2 ! misho 115: debug_decl(cleanup, SUDO_DEBUG_EXEC);
! 116:
! 117: if (!tq_empty(&io_plugins) && io_fds[SFD_USERTTY] != -1) {
! 118: check_foreground();
! 119: if (foreground)
! 120: term_restore(io_fds[SFD_USERTTY], 0);
! 121: }
1.1 misho 122: #ifdef HAVE_SELINUX
123: selinux_restore_tty();
124: #endif
125: utmp_logout(slavename, 0); /* XXX - only if CD_SET_UTMP */
1.1.1.2 ! misho 126:
! 127: debug_return;
1.1 misho 128: }
129:
130: /*
131: * Allocate a pty if /dev/tty is a tty.
132: * Fills in io_fds[SFD_USERTTY], io_fds[SFD_MASTER], io_fds[SFD_SLAVE]
133: * and slavename globals.
134: */
135: void
136: pty_setup(uid_t uid, const char *tty, const char *utmp_user)
137: {
1.1.1.2 ! misho 138: debug_decl(pty_setup, SUDO_DEBUG_EXEC);
! 139:
1.1 misho 140: io_fds[SFD_USERTTY] = open(_PATH_TTY, O_RDWR|O_NOCTTY, 0);
141: if (io_fds[SFD_USERTTY] != -1) {
142: if (!get_pty(&io_fds[SFD_MASTER], &io_fds[SFD_SLAVE],
143: slavename, sizeof(slavename), uid))
144: error(1, _("unable to allocate pty"));
145: /* Add entry to utmp/utmpx? */
146: if (utmp_user != NULL)
147: utmp_login(tty, slavename, io_fds[SFD_SLAVE], utmp_user);
148: }
1.1.1.2 ! misho 149:
! 150: debug_return;
1.1 misho 151: }
152:
153: /* Call I/O plugin tty input log method. */
1.1.1.2 ! misho 154: static bool
1.1 misho 155: log_ttyin(const char *buf, unsigned int n)
156: {
157: struct plugin_container *plugin;
158: sigset_t omask;
1.1.1.2 ! misho 159: bool rval = true;
! 160: debug_decl(log_ttyin, SUDO_DEBUG_EXEC);
1.1 misho 161:
162: sigprocmask(SIG_BLOCK, &ttyblock, &omask);
163: tq_foreach_fwd(&io_plugins, plugin) {
164: if (plugin->u.io->log_ttyin) {
165: if (!plugin->u.io->log_ttyin(buf, n)) {
1.1.1.2 ! misho 166: rval = false;
1.1 misho 167: break;
168: }
169: }
170: }
171: sigprocmask(SIG_SETMASK, &omask, NULL);
1.1.1.2 ! misho 172:
! 173: debug_return_bool(rval);
1.1 misho 174: }
175:
176: /* Call I/O plugin stdin log method. */
1.1.1.2 ! misho 177: static bool
1.1 misho 178: log_stdin(const char *buf, unsigned int n)
179: {
180: struct plugin_container *plugin;
181: sigset_t omask;
1.1.1.2 ! misho 182: bool rval = true;
! 183: debug_decl(log_stdin, SUDO_DEBUG_EXEC);
1.1 misho 184:
185: sigprocmask(SIG_BLOCK, &ttyblock, &omask);
186: tq_foreach_fwd(&io_plugins, plugin) {
187: if (plugin->u.io->log_stdin) {
188: if (!plugin->u.io->log_stdin(buf, n)) {
1.1.1.2 ! misho 189: rval = false;
1.1 misho 190: break;
191: }
192: }
193: }
194: sigprocmask(SIG_SETMASK, &omask, NULL);
1.1.1.2 ! misho 195:
! 196: debug_return_bool(rval);
1.1 misho 197: }
198:
199: /* Call I/O plugin tty output log method. */
1.1.1.2 ! misho 200: static bool
1.1 misho 201: log_ttyout(const char *buf, unsigned int n)
202: {
203: struct plugin_container *plugin;
204: sigset_t omask;
1.1.1.2 ! misho 205: bool rval = true;
! 206: debug_decl(log_ttyout, SUDO_DEBUG_EXEC);
1.1 misho 207:
208: sigprocmask(SIG_BLOCK, &ttyblock, &omask);
209: tq_foreach_fwd(&io_plugins, plugin) {
210: if (plugin->u.io->log_ttyout) {
211: if (!plugin->u.io->log_ttyout(buf, n)) {
1.1.1.2 ! misho 212: rval = false;
1.1 misho 213: break;
214: }
215: }
216: }
217: sigprocmask(SIG_SETMASK, &omask, NULL);
1.1.1.2 ! misho 218:
! 219: debug_return_bool(rval);
1.1 misho 220: }
221:
222: /* Call I/O plugin stdout log method. */
1.1.1.2 ! misho 223: static bool
1.1 misho 224: log_stdout(const char *buf, unsigned int n)
225: {
226: struct plugin_container *plugin;
227: sigset_t omask;
1.1.1.2 ! misho 228: bool rval = true;
! 229: debug_decl(log_stdout, SUDO_DEBUG_EXEC);
1.1 misho 230:
231: sigprocmask(SIG_BLOCK, &ttyblock, &omask);
232: tq_foreach_fwd(&io_plugins, plugin) {
233: if (plugin->u.io->log_stdout) {
234: if (!plugin->u.io->log_stdout(buf, n)) {
1.1.1.2 ! misho 235: rval = false;
1.1 misho 236: break;
237: }
238: }
239: }
240: sigprocmask(SIG_SETMASK, &omask, NULL);
1.1.1.2 ! misho 241:
! 242: debug_return_bool(rval);
1.1 misho 243: }
244:
245: /* Call I/O plugin stderr log method. */
1.1.1.2 ! misho 246: static bool
1.1 misho 247: log_stderr(const char *buf, unsigned int n)
248: {
249: struct plugin_container *plugin;
250: sigset_t omask;
1.1.1.2 ! misho 251: bool rval = true;
! 252: debug_decl(log_stderr, SUDO_DEBUG_EXEC);
1.1 misho 253:
254: sigprocmask(SIG_BLOCK, &ttyblock, &omask);
255: tq_foreach_fwd(&io_plugins, plugin) {
256: if (plugin->u.io->log_stderr) {
257: if (!plugin->u.io->log_stderr(buf, n)) {
1.1.1.2 ! misho 258: rval = false;
1.1 misho 259: break;
260: }
261: }
262: }
263: sigprocmask(SIG_SETMASK, &omask, NULL);
1.1.1.2 ! misho 264:
! 265: debug_return_bool(rval);
1.1 misho 266: }
267:
268: /*
269: * Check whether we are running in the foregroup.
270: * Updates the foreground global and does lazy init of the
271: * the pty slave as needed.
272: */
273: static void
274: check_foreground(void)
275: {
1.1.1.2 ! misho 276: debug_decl(check_foreground, SUDO_DEBUG_EXEC);
! 277:
1.1 misho 278: if (io_fds[SFD_USERTTY] != -1) {
279: foreground = tcgetpgrp(io_fds[SFD_USERTTY]) == ppgrp;
280: if (foreground && !tty_initialized) {
281: if (term_copy(io_fds[SFD_USERTTY], io_fds[SFD_SLAVE])) {
1.1.1.2 ! misho 282: tty_initialized = true;
1.1 misho 283: sync_ttysize(io_fds[SFD_USERTTY], io_fds[SFD_SLAVE]);
284: }
285: }
286: }
1.1.1.2 ! misho 287:
! 288: debug_return;
1.1 misho 289: }
290:
291: /*
292: * Suspend sudo if the underlying command is suspended.
293: * Returns SIGCONT_FG if the child should be resume in the
294: * foreground or SIGCONT_BG if it is a background process.
295: */
296: int
297: suspend_parent(int signo)
298: {
299: sigaction_t sa, osa;
300: int n, oldmode = ttymode, rval = 0;
1.1.1.2 ! misho 301: debug_decl(suspend_parent, SUDO_DEBUG_EXEC);
1.1 misho 302:
303: switch (signo) {
304: case SIGTTOU:
305: case SIGTTIN:
306: /*
307: * If we are the foreground process, just resume the child.
308: * Otherwise, re-send the signal with the handler disabled.
309: */
310: if (!foreground)
311: check_foreground();
312: if (foreground) {
313: if (ttymode != TERM_RAW) {
314: do {
315: n = term_raw(io_fds[SFD_USERTTY], 0);
316: } while (!n && errno == EINTR);
317: ttymode = TERM_RAW;
318: }
319: rval = SIGCONT_FG; /* resume child in foreground */
320: break;
321: }
322: ttymode = TERM_RAW;
323: /* FALLTHROUGH */
324: case SIGSTOP:
325: case SIGTSTP:
326: /* Flush any remaining output before suspending. */
327: flush_output();
328:
329: /* Restore original tty mode before suspending. */
330: if (oldmode != TERM_COOKED) {
331: do {
332: n = term_restore(io_fds[SFD_USERTTY], 0);
333: } while (!n && errno == EINTR);
334: }
335:
336: /* Suspend self and continue child when we resume. */
1.1.1.2 ! misho 337: zero_bytes(&sa, sizeof(sa));
! 338: sigemptyset(&sa.sa_mask);
! 339: sa.sa_flags = SA_INTERRUPT; /* do not restart syscalls */
1.1 misho 340: sa.sa_handler = SIG_DFL;
341: sigaction(signo, &sa, &osa);
1.1.1.2 ! misho 342: sudo_debug_printf(SUDO_DEBUG_INFO, "kill parent %d", signo);
1.1 misho 343: if (killpg(ppgrp, signo) != 0)
344: warning("killpg(%d, %d)", (int)ppgrp, signo);
345:
346: /* Check foreground/background status on resume. */
347: check_foreground();
348:
349: /*
350: * Only modify term if we are foreground process and either
351: * the old tty mode was not cooked or child got SIGTT{IN,OU}
352: */
1.1.1.2 ! misho 353: sudo_debug_printf(SUDO_DEBUG_INFO, "parent is in %s, ttymode %d -> %d",
1.1 misho 354: foreground ? "foreground" : "background", oldmode, ttymode);
355:
356: if (ttymode != TERM_COOKED) {
357: if (foreground) {
358: /* Set raw mode. */
359: do {
360: n = term_raw(io_fds[SFD_USERTTY], 0);
361: } while (!n && errno == EINTR);
362: } else {
363: /* Background process, no access to tty. */
364: ttymode = TERM_COOKED;
365: }
366: }
367:
368: sigaction(signo, &osa, NULL);
369: rval = ttymode == TERM_RAW ? SIGCONT_FG : SIGCONT_BG;
370: break;
371: }
372:
1.1.1.2 ! misho 373: debug_return_int(rval);
1.1 misho 374: }
375:
376: /*
377: * Kill child with increasing urgency.
378: */
379: void
1.1.1.2 ! misho 380: terminate_child(pid_t pid, bool use_pgrp)
1.1 misho 381: {
1.1.1.2 ! misho 382: debug_decl(terminate_child, SUDO_DEBUG_EXEC);
! 383:
1.1 misho 384: /*
385: * Note that SIGCHLD will interrupt the sleep()
386: */
387: if (use_pgrp) {
1.1.1.2 ! misho 388: sudo_debug_printf(SUDO_DEBUG_INFO, "killpg %d SIGHUP", (int)pid);
1.1 misho 389: killpg(pid, SIGHUP);
1.1.1.2 ! misho 390: sudo_debug_printf(SUDO_DEBUG_INFO, "killpg %d SIGTERM", (int)pid);
1.1 misho 391: killpg(pid, SIGTERM);
392: sleep(2);
1.1.1.2 ! misho 393: sudo_debug_printf(SUDO_DEBUG_INFO, "killpg %d SIGKILL", (int)pid);
1.1 misho 394: killpg(pid, SIGKILL);
395: } else {
1.1.1.2 ! misho 396: sudo_debug_printf(SUDO_DEBUG_INFO, "kill %d SIGHUP", (int)pid);
1.1 misho 397: kill(pid, SIGHUP);
1.1.1.2 ! misho 398: sudo_debug_printf(SUDO_DEBUG_INFO, "kill %d SIGTERM", (int)pid);
1.1 misho 399: kill(pid, SIGTERM);
400: sleep(2);
1.1.1.2 ! misho 401: sudo_debug_printf(SUDO_DEBUG_INFO, "kill %d SIGKILL", (int)pid);
1.1 misho 402: kill(pid, SIGKILL);
403: }
1.1.1.2 ! misho 404:
! 405: debug_return;
1.1 misho 406: }
407:
408: static struct io_buffer *
1.1.1.2 ! misho 409: io_buf_new(int rfd, int wfd, bool (*action)(const char *, unsigned int),
1.1 misho 410: struct io_buffer *head)
411: {
412: struct io_buffer *iob;
1.1.1.2 ! misho 413: debug_decl(io_buf_new, SUDO_DEBUG_EXEC);
1.1 misho 414:
1.1.1.2 ! misho 415: iob = ecalloc(1, sizeof(*iob));
1.1 misho 416: iob->rfd = rfd;
417: iob->wfd = wfd;
418: iob->action = action;
419: iob->next = head;
1.1.1.2 ! misho 420:
! 421: debug_return_ptr(iob);
1.1 misho 422: }
423:
424: /*
425: * Read/write iobufs depending on fdsr and fdsw.
426: * Returns the number of errors.
427: */
428: int
429: perform_io(fd_set *fdsr, fd_set *fdsw, struct command_status *cstat)
430: {
431: struct io_buffer *iob;
432: int n, errors = 0;
1.1.1.2 ! misho 433: debug_decl(perform_io, SUDO_DEBUG_EXEC);
1.1 misho 434:
435: for (iob = iobufs; iob; iob = iob->next) {
436: if (iob->rfd != -1 && FD_ISSET(iob->rfd, fdsr)) {
437: do {
438: n = read(iob->rfd, iob->buf + iob->len,
439: sizeof(iob->buf) - iob->len);
440: } while (n == -1 && errno == EINTR);
441: switch (n) {
442: case -1:
1.1.1.2 ! misho 443: if (errno != EAGAIN) {
! 444: /* treat read error as fatal and close the fd */
! 445: sudo_debug_printf(SUDO_DEBUG_ERROR,
! 446: "error reading fd %d: %s", iob->rfd,
! 447: strerror(errno));
! 448: safe_close(iob->rfd);
! 449: iob->rfd = -1;
1.1 misho 450: }
1.1.1.2 ! misho 451: break;
1.1 misho 452: case 0:
453: /* got EOF or pty has gone away */
1.1.1.2 ! misho 454: sudo_debug_printf(SUDO_DEBUG_INFO,
! 455: "read EOF from fd %d", iob->rfd);
1.1 misho 456: safe_close(iob->rfd);
457: iob->rfd = -1;
458: break;
459: default:
1.1.1.2 ! misho 460: sudo_debug_printf(SUDO_DEBUG_INFO,
! 461: "read %d bytes from fd %d", n, iob->rfd);
1.1 misho 462: if (!iob->action(iob->buf + iob->len, n))
1.1.1.2 ! misho 463: terminate_child(child, true);
1.1 misho 464: iob->len += n;
465: break;
466: }
467: }
468: if (iob->wfd != -1 && FD_ISSET(iob->wfd, fdsw)) {
469: do {
470: n = write(iob->wfd, iob->buf + iob->off,
471: iob->len - iob->off);
472: } while (n == -1 && errno == EINTR);
473: if (n == -1) {
1.1.1.2 ! misho 474: if (errno == EPIPE || errno == ENXIO || errno == EIO || errno == EBADF) {
! 475: sudo_debug_printf(SUDO_DEBUG_INFO,
! 476: "unable to write %d bytes to fd %d",
! 477: iob->len - iob->off, iob->wfd);
1.1 misho 478: /* other end of pipe closed or pty revoked */
479: if (iob->rfd != -1) {
480: safe_close(iob->rfd);
481: iob->rfd = -1;
482: }
483: safe_close(iob->wfd);
484: iob->wfd = -1;
485: continue;
486: }
1.1.1.2 ! misho 487: if (errno != EAGAIN) {
1.1 misho 488: errors++;
1.1.1.2 ! misho 489: sudo_debug_printf(SUDO_DEBUG_ERROR,
! 490: "error writing fd %d: %s", iob->wfd, strerror(errno));
! 491: }
1.1 misho 492: } else {
1.1.1.2 ! misho 493: sudo_debug_printf(SUDO_DEBUG_INFO,
! 494: "wrote %d bytes to fd %d", n, iob->wfd);
1.1 misho 495: iob->off += n;
496: }
497: }
498: }
499: if (errors && cstat != NULL) {
500: cstat->type = CMD_ERRNO;
501: cstat->val = errno;
502: }
1.1.1.2 ! misho 503: debug_return_int(errors);
1.1 misho 504: }
505:
506: /*
507: * Fork a monitor process which runs the actual command as its own child
508: * process with std{in,out,err} hooked up to the pty or pipes as appropriate.
509: * Returns the child pid.
510: */
511: int
512: fork_pty(struct command_details *details, int sv[], int *maxfd)
513: {
514: struct command_status cstat;
515: struct io_buffer *iob;
516: int io_pipe[3][2], n;
517: sigaction_t sa;
1.1.1.2 ! misho 518: debug_decl(fork_pty, SUDO_DEBUG_EXEC);
1.1 misho 519:
520: ppgrp = getpgrp(); /* parent's pgrp, so child can signal us */
521:
522: zero_bytes(&sa, sizeof(sa));
523: sigemptyset(&sa.sa_mask);
524:
525: if (io_fds[SFD_USERTTY] != -1) {
526: sa.sa_flags = SA_RESTART;
527: sa.sa_handler = sigwinch;
528: sigaction(SIGWINCH, &sa, NULL);
529: }
530:
531: /* So we can block tty-generated signals */
532: sigemptyset(&ttyblock);
533: sigaddset(&ttyblock, SIGINT);
534: sigaddset(&ttyblock, SIGQUIT);
535: sigaddset(&ttyblock, SIGTSTP);
536: sigaddset(&ttyblock, SIGTTIN);
537: sigaddset(&ttyblock, SIGTTOU);
538:
539: /*
540: * Setup stdin/stdout/stderr for child, to be duped after forking.
541: * In background mode there is no stdin.
542: */
543: if (!ISSET(details->flags, CD_BACKGROUND))
544: io_fds[SFD_STDIN] = io_fds[SFD_SLAVE];
545: io_fds[SFD_STDOUT] = io_fds[SFD_SLAVE];
546: io_fds[SFD_STDERR] = io_fds[SFD_SLAVE];
547:
548: if (io_fds[SFD_USERTTY] != -1) {
549: /* Read from /dev/tty, write to pty master */
550: if (!ISSET(details->flags, CD_BACKGROUND)) {
551: iobufs = io_buf_new(io_fds[SFD_USERTTY], io_fds[SFD_MASTER],
552: log_ttyin, iobufs);
553: }
554:
555: /* Read from pty master, write to /dev/tty */
556: iobufs = io_buf_new(io_fds[SFD_MASTER], io_fds[SFD_USERTTY],
557: log_ttyout, iobufs);
558:
559: /* Are we the foreground process? */
560: foreground = tcgetpgrp(io_fds[SFD_USERTTY]) == ppgrp;
561: }
562:
563: /*
564: * If either stdin, stdout or stderr is not a tty we use a pipe
565: * to interpose ourselves instead of duping the pty fd.
566: */
567: memset(io_pipe, 0, sizeof(io_pipe));
568: if (io_fds[SFD_STDIN] == -1 || !isatty(STDIN_FILENO)) {
1.1.1.2 ! misho 569: sudo_debug_printf(SUDO_DEBUG_INFO, "stdin not a tty, creating a pipe");
! 570: pipeline = true;
1.1 misho 571: if (pipe(io_pipe[STDIN_FILENO]) != 0)
572: error(1, _("unable to create pipe"));
573: iobufs = io_buf_new(STDIN_FILENO, io_pipe[STDIN_FILENO][1],
574: log_stdin, iobufs);
575: io_fds[SFD_STDIN] = io_pipe[STDIN_FILENO][0];
576: }
577: if (io_fds[SFD_STDOUT] == -1 || !isatty(STDOUT_FILENO)) {
1.1.1.2 ! misho 578: sudo_debug_printf(SUDO_DEBUG_INFO, "stdout not a tty, creating a pipe");
! 579: pipeline = true;
1.1 misho 580: if (pipe(io_pipe[STDOUT_FILENO]) != 0)
581: error(1, _("unable to create pipe"));
582: iobufs = io_buf_new(io_pipe[STDOUT_FILENO][0], STDOUT_FILENO,
583: log_stdout, iobufs);
584: io_fds[SFD_STDOUT] = io_pipe[STDOUT_FILENO][1];
585: }
586: if (io_fds[SFD_STDERR] == -1 || !isatty(STDERR_FILENO)) {
1.1.1.2 ! misho 587: sudo_debug_printf(SUDO_DEBUG_INFO, "stderr not a tty, creating a pipe");
1.1 misho 588: if (pipe(io_pipe[STDERR_FILENO]) != 0)
589: error(1, _("unable to create pipe"));
590: iobufs = io_buf_new(io_pipe[STDERR_FILENO][0], STDERR_FILENO,
591: log_stderr, iobufs);
592: io_fds[SFD_STDERR] = io_pipe[STDERR_FILENO][1];
593: }
594:
595: /* Job control signals to relay from parent to child. */
596: sa.sa_flags = SA_INTERRUPT; /* do not restart syscalls */
597: sa.sa_handler = handler;
598: sigaction(SIGTSTP, &sa, NULL);
599:
1.1.1.2 ! misho 600: /* We don't want to receive SIGTTIN/SIGTTOU, getting EIO is preferable. */
! 601: sa.sa_handler = SIG_IGN;
! 602: sigaction(SIGTTIN, &sa, NULL);
! 603: sigaction(SIGTTOU, &sa, NULL);
! 604:
1.1 misho 605: if (foreground) {
606: /* Copy terminal attrs from user tty -> pty slave. */
607: if (term_copy(io_fds[SFD_USERTTY], io_fds[SFD_SLAVE])) {
1.1.1.2 ! misho 608: tty_initialized = true;
1.1 misho 609: sync_ttysize(io_fds[SFD_USERTTY], io_fds[SFD_SLAVE]);
610: }
611:
612: /* Start out in raw mode if we are not part of a pipeline. */
613: if (!pipeline) {
614: ttymode = TERM_RAW;
615: do {
616: n = term_raw(io_fds[SFD_USERTTY], 0);
617: } while (!n && errno == EINTR);
618: if (!n)
619: error(1, _("unable to set terminal to raw mode"));
620: }
621: }
622:
1.1.1.2 ! misho 623: /*
! 624: * The policy plugin's session init must be run before we fork
! 625: * or certain pam modules won't be able to track their state.
! 626: */
! 627: if (policy_init_session(details) != true)
! 628: errorx(1, _("policy plugin failed session initialization"));
! 629:
! 630: child = sudo_debug_fork();
1.1 misho 631: switch (child) {
632: case -1:
633: error(1, _("unable to fork"));
634: break;
635: case 0:
636: /* child */
637: close(sv[0]);
638: close(signal_pipe[0]);
639: close(signal_pipe[1]);
640: fcntl(sv[1], F_SETFD, FD_CLOEXEC);
1.1.1.2 ! misho 641: if (exec_setup(details, slavename, io_fds[SFD_SLAVE]) == true) {
1.1 misho 642: /* Close the other end of the stdin/stdout/stderr pipes and exec. */
643: if (io_pipe[STDIN_FILENO][1])
644: close(io_pipe[STDIN_FILENO][1]);
645: if (io_pipe[STDOUT_FILENO][0])
646: close(io_pipe[STDOUT_FILENO][0]);
647: if (io_pipe[STDERR_FILENO][0])
648: close(io_pipe[STDERR_FILENO][0]);
649: exec_monitor(details, sv[1]);
650: }
651: cstat.type = CMD_ERRNO;
652: cstat.val = errno;
653: send(sv[1], &cstat, sizeof(cstat), 0);
654: _exit(1);
655: }
656:
657: /* Close the other end of the stdin/stdout/stderr pipes. */
658: if (io_pipe[STDIN_FILENO][0])
659: close(io_pipe[STDIN_FILENO][0]);
660: if (io_pipe[STDOUT_FILENO][1])
661: close(io_pipe[STDOUT_FILENO][1]);
662: if (io_pipe[STDERR_FILENO][1])
663: close(io_pipe[STDERR_FILENO][1]);
664:
665: for (iob = iobufs; iob; iob = iob->next) {
666: /* Determine maxfd */
667: if (iob->rfd > *maxfd)
668: *maxfd = iob->rfd;
669: if (iob->wfd > *maxfd)
670: *maxfd = iob->wfd;
671:
672: /* Set non-blocking mode. */
673: n = fcntl(iob->rfd, F_GETFL, 0);
674: if (n != -1 && !ISSET(n, O_NONBLOCK))
675: (void) fcntl(iob->rfd, F_SETFL, n | O_NONBLOCK);
676: n = fcntl(iob->wfd, F_GETFL, 0);
677: if (n != -1 && !ISSET(n, O_NONBLOCK))
678: (void) fcntl(iob->wfd, F_SETFL, n | O_NONBLOCK);
679: }
680:
1.1.1.2 ! misho 681: debug_return_int(child);
1.1 misho 682: }
683:
684: void
685: pty_close(struct command_status *cstat)
686: {
687: int n;
1.1.1.2 ! misho 688: debug_decl(pty_close, SUDO_DEBUG_EXEC);
1.1 misho 689:
690: /* Flush any remaining output (the plugin already got it) */
691: if (io_fds[SFD_USERTTY] != -1) {
692: n = fcntl(io_fds[SFD_USERTTY], F_GETFL, 0);
693: if (n != -1 && ISSET(n, O_NONBLOCK)) {
694: CLR(n, O_NONBLOCK);
695: (void) fcntl(io_fds[SFD_USERTTY], F_SETFL, n);
696: }
697: }
698: flush_output();
699:
700: if (io_fds[SFD_USERTTY] != -1) {
1.1.1.2 ! misho 701: check_foreground();
! 702: if (foreground) {
! 703: do {
! 704: n = term_restore(io_fds[SFD_USERTTY], 0);
! 705: } while (!n && errno == EINTR);
! 706: }
1.1 misho 707: }
708:
709: /* If child was signalled, write the reason to stdout like the shell. */
710: if (cstat->type == CMD_WSTATUS && WIFSIGNALED(cstat->val)) {
711: int signo = WTERMSIG(cstat->val);
712: if (signo && signo != SIGINT && signo != SIGPIPE) {
713: const char *reason = strsignal(signo);
714: n = io_fds[SFD_USERTTY] != -1 ?
715: io_fds[SFD_USERTTY] : STDOUT_FILENO;
716: if (write(n, reason, strlen(reason)) != -1) {
717: if (WCOREDUMP(cstat->val)) {
1.1.1.2 ! misho 718: ignore_result(write(n, " (core dumped)", 14));
1.1 misho 719: }
1.1.1.2 ! misho 720: ignore_result(write(n, "\n", 1));
1.1 misho 721: }
722: }
723: }
724: utmp_logout(slavename, cstat->type == CMD_WSTATUS ? cstat->val : 0); /* XXX - only if CD_SET_UTMP */
1.1.1.2 ! misho 725: debug_return;
1.1 misho 726: }
727:
728: /*
729: * Fill in fdsr and fdsw based on the io buffers list.
730: * Called prior to select().
731: */
732: void
733: fd_set_iobs(fd_set *fdsr, fd_set *fdsw)
734: {
735: struct io_buffer *iob;
1.1.1.2 ! misho 736: debug_decl(fd_set_iobs, SUDO_DEBUG_EXEC);
1.1 misho 737:
738: for (iob = iobufs; iob; iob = iob->next) {
739: if (iob->rfd == -1 && iob->wfd == -1)
740: continue;
741: if (iob->off == iob->len) {
742: iob->off = iob->len = 0;
743: /* Forward the EOF from reader to writer. */
744: if (iob->rfd == -1) {
745: safe_close(iob->wfd);
746: iob->wfd = -1;
747: }
748: }
749: /* Don't read/write /dev/tty if we are not in the foreground. */
750: if (iob->rfd != -1 &&
751: (ttymode == TERM_RAW || iob->rfd != io_fds[SFD_USERTTY])) {
752: if (iob->len != sizeof(iob->buf))
753: FD_SET(iob->rfd, fdsr);
754: }
755: if (iob->wfd != -1 &&
756: (foreground || iob->wfd != io_fds[SFD_USERTTY])) {
757: if (iob->len > iob->off)
758: FD_SET(iob->wfd, fdsw);
759: }
760: }
1.1.1.2 ! misho 761: debug_return;
1.1 misho 762: }
763:
764: static void
1.1.1.2 ! misho 765: deliver_signal(pid_t pid, int signo, bool from_parent)
1.1 misho 766: {
767: int status;
1.1.1.2 ! misho 768: debug_decl(deliver_signal, SUDO_DEBUG_EXEC);
1.1 misho 769:
770: /* Handle signal from parent. */
1.1.1.2 ! misho 771: sudo_debug_printf(SUDO_DEBUG_INFO, "received signal %d%s", signo,
! 772: from_parent ? " from parent" : "");
1.1 misho 773: switch (signo) {
774: case SIGALRM:
1.1.1.2 ! misho 775: terminate_child(pid, true);
1.1 misho 776: break;
777: case SIGCONT_FG:
778: /* Continue in foreground, grant it controlling tty. */
779: do {
780: status = tcsetpgrp(io_fds[SFD_SLAVE], child_pgrp);
781: } while (status == -1 && errno == EINTR);
782: killpg(pid, SIGCONT);
783: break;
784: case SIGCONT_BG:
785: /* Continue in background, I take controlling tty. */
786: do {
787: status = tcsetpgrp(io_fds[SFD_SLAVE], getpid());
788: } while (status == -1 && errno == EINTR);
789: killpg(pid, SIGCONT);
790: break;
791: case SIGKILL:
792: _exit(1); /* XXX */
793: /* NOTREACHED */
794: default:
795: /* Relay signal to child. */
796: killpg(pid, signo);
797: break;
798: }
1.1.1.2 ! misho 799: debug_return;
1.1 misho 800: }
801:
802: /*
803: * Send status to parent over socketpair.
804: * Return value is the same as send(2).
805: */
806: static int
807: send_status(int fd, struct command_status *cstat)
808: {
809: int n = -1;
1.1.1.2 ! misho 810: debug_decl(send_status, SUDO_DEBUG_EXEC);
1.1 misho 811:
812: if (cstat->type != CMD_INVALID) {
1.1.1.2 ! misho 813: sudo_debug_printf(SUDO_DEBUG_INFO,
! 814: "sending status message to parent: [%d, %d]",
! 815: cstat->type, cstat->val);
1.1 misho 816: do {
817: n = send(fd, cstat, sizeof(*cstat), 0);
818: } while (n == -1 && errno == EINTR);
819: if (n != sizeof(*cstat)) {
1.1.1.2 ! misho 820: sudo_debug_printf(SUDO_DEBUG_ERROR,
! 821: "unable to send status to parent: %s", strerror(errno));
1.1 misho 822: }
823: cstat->type = CMD_INVALID; /* prevent re-sending */
824: }
1.1.1.2 ! misho 825: debug_return_int(n);
1.1 misho 826: }
827:
828: /*
829: * Wait for child status after receiving SIGCHLD.
830: * If the child was stopped, the status is send back to the parent.
831: * Otherwise, cstat is filled in but not sent.
1.1.1.2 ! misho 832: * Returns true if child is still alive, else false.
1.1 misho 833: */
1.1.1.2 ! misho 834: static bool
1.1 misho 835: handle_sigchld(int backchannel, struct command_status *cstat)
836: {
1.1.1.2 ! misho 837: bool alive = true;
! 838: int status;
1.1 misho 839: pid_t pid;
1.1.1.2 ! misho 840: debug_decl(handle_sigchld, SUDO_DEBUG_EXEC);
1.1 misho 841:
842: /* read child status */
843: do {
844: pid = waitpid(child, &status, WUNTRACED|WNOHANG);
845: } while (pid == -1 && errno == EINTR);
846: if (pid == child) {
847: if (cstat->type != CMD_ERRNO) {
848: cstat->type = CMD_WSTATUS;
849: cstat->val = status;
850: if (WIFSTOPPED(status)) {
1.1.1.2 ! misho 851: sudo_debug_printf(SUDO_DEBUG_INFO, "command stopped, signal %d",
! 852: WSTOPSIG(status));
1.1 misho 853: do {
854: child_pgrp = tcgetpgrp(io_fds[SFD_SLAVE]);
855: } while (child_pgrp == -1 && errno == EINTR);
856: if (send_status(backchannel, cstat) == -1)
857: return alive; /* XXX */
858: } else if (WIFSIGNALED(status)) {
1.1.1.2 ! misho 859: sudo_debug_printf(SUDO_DEBUG_INFO, "command killed, signal %d",
! 860: WTERMSIG(status));
1.1 misho 861: } else {
1.1.1.2 ! misho 862: sudo_debug_printf(SUDO_DEBUG_INFO, "command exited: %d",
! 863: WEXITSTATUS(status));
1.1 misho 864: }
865: }
866: if (!WIFSTOPPED(status))
1.1.1.2 ! misho 867: alive = false;
1.1 misho 868: }
1.1.1.2 ! misho 869: debug_return_bool(alive);
1.1 misho 870: }
871:
872: /*
873: * Monitor process that creates a new session with the controlling tty,
874: * resets signal handlers and forks a child to call exec_pty().
875: * Waits for status changes from the command and relays them to the
876: * parent and relays signals from the parent to the command.
877: * Returns an error if fork(2) fails, else calls _exit(2).
878: */
879: static int
880: exec_monitor(struct command_details *details, int backchannel)
881: {
882: struct command_status cstat;
883: struct timeval tv;
884: fd_set *fdsr;
885: sigaction_t sa;
886: int errpipe[2], maxfd, n, status;
1.1.1.2 ! misho 887: bool alive = true;
1.1 misho 888: unsigned char signo;
1.1.1.2 ! misho 889: debug_decl(exec_monitor, SUDO_DEBUG_EXEC);
1.1 misho 890:
891: /* Close unused fds. */
892: if (io_fds[SFD_MASTER] != -1)
893: close(io_fds[SFD_MASTER]);
894: if (io_fds[SFD_USERTTY] != -1)
895: close(io_fds[SFD_USERTTY]);
896:
897: /*
898: * We use a pipe to atomically handle signal notification within
899: * the select() loop.
900: */
901: if (pipe_nonblock(signal_pipe) != 0)
902: error(1, _("unable to create pipe"));
903:
904: /* Reset SIGWINCH and SIGALRM. */
905: zero_bytes(&sa, sizeof(sa));
906: sigemptyset(&sa.sa_mask);
907: sa.sa_flags = SA_RESTART;
908: sa.sa_handler = SIG_DFL;
909: sigaction(SIGWINCH, &sa, NULL);
910: sigaction(SIGALRM, &sa, NULL);
911:
912: /* Ignore any SIGTTIN or SIGTTOU we get. */
913: sa.sa_handler = SIG_IGN;
914: sigaction(SIGTTIN, &sa, NULL);
915: sigaction(SIGTTOU, &sa, NULL);
916:
917: /* Note: HP-UX select() will not be interrupted if SA_RESTART set */
918: sa.sa_flags = SA_INTERRUPT;
919: sa.sa_handler = handler;
920: sigaction(SIGCHLD, &sa, NULL);
921:
1.1.1.2 ! misho 922: /* Catch common signals so we can cleanup properly. */
! 923: sa.sa_flags = SA_RESTART;
! 924: sa.sa_handler = handler;
! 925: sigaction(SIGHUP, &sa, NULL);
! 926: sigaction(SIGINT, &sa, NULL);
! 927: sigaction(SIGQUIT, &sa, NULL);
! 928: sigaction(SIGTERM, &sa, NULL);
! 929: sigaction(SIGTSTP, &sa, NULL);
! 930: sigaction(SIGUSR1, &sa, NULL);
! 931: sigaction(SIGUSR2, &sa, NULL);
! 932:
1.1 misho 933: /*
934: * Start a new session with the parent as the session leader
935: * and the slave pty as the controlling terminal.
936: * This allows us to be notified when the child has been suspended.
937: */
938: if (setsid() == -1) {
939: warning("setsid");
940: goto bad;
941: }
942: if (io_fds[SFD_SLAVE] != -1) {
943: #ifdef TIOCSCTTY
944: if (ioctl(io_fds[SFD_SLAVE], TIOCSCTTY, NULL) != 0)
945: error(1, _("unable to set controlling tty"));
946: #else
947: /* Set controlling tty by reopening slave. */
948: if ((n = open(slavename, O_RDWR)) >= 0)
949: close(n);
950: #endif
951: }
952:
953: /*
954: * If stdin/stdout is not a tty, start command in the background
955: * since it might be part of a pipeline that reads from /dev/tty.
956: * In this case, we rely on the command receiving SIGTTOU or SIGTTIN
957: * when it needs access to the controlling tty.
958: */
959: if (pipeline)
1.1.1.2 ! misho 960: foreground = false;
1.1 misho 961:
962: /* Start command and wait for it to stop or exit */
963: if (pipe(errpipe) == -1)
964: error(1, _("unable to create pipe"));
1.1.1.2 ! misho 965: child = sudo_debug_fork();
1.1 misho 966: if (child == -1) {
967: warning(_("unable to fork"));
968: goto bad;
969: }
970: if (child == 0) {
971: /* We pass errno back to our parent via pipe on exec failure. */
972: close(backchannel);
973: close(signal_pipe[0]);
974: close(signal_pipe[1]);
975: close(errpipe[0]);
976: fcntl(errpipe[1], F_SETFD, FD_CLOEXEC);
977: restore_signals();
978:
979: /* setup tty and exec command */
1.1.1.2 ! misho 980: exec_pty(details, &errpipe[1]);
1.1 misho 981: cstat.type = CMD_ERRNO;
982: cstat.val = errno;
1.1.1.2 ! misho 983: ignore_result(write(errpipe[1], &cstat, sizeof(cstat)));
1.1 misho 984: _exit(1);
985: }
986: close(errpipe[1]);
987:
988: /* If any of stdin/stdout/stderr are pipes, close them in parent. */
989: if (io_fds[SFD_STDIN] != io_fds[SFD_SLAVE])
990: close(io_fds[SFD_STDIN]);
991: if (io_fds[SFD_STDOUT] != io_fds[SFD_SLAVE])
992: close(io_fds[SFD_STDOUT]);
993: if (io_fds[SFD_STDERR] != io_fds[SFD_SLAVE])
994: close(io_fds[SFD_STDERR]);
995:
996: /*
997: * Put child in its own process group. If we are starting the command
998: * in the foreground, assign its pgrp to the tty.
999: */
1000: child_pgrp = child;
1001: setpgid(child, child_pgrp);
1002: if (foreground) {
1003: do {
1004: status = tcsetpgrp(io_fds[SFD_SLAVE], child_pgrp);
1005: } while (status == -1 && errno == EINTR);
1006: }
1007:
1008: /* Wait for errno on pipe, signal on backchannel or for SIGCHLD */
1009: maxfd = MAX(MAX(errpipe[0], signal_pipe[0]), backchannel);
1.1.1.2 ! misho 1010: fdsr = ecalloc(howmany(maxfd + 1, NFDBITS), sizeof(fd_mask));
! 1011: memset(&cstat, 0, sizeof(cstat));
1.1 misho 1012: tv.tv_sec = 0;
1013: tv.tv_usec = 0;
1014: for (;;) {
1015: /* Check for signal on backchannel or errno on errpipe. */
1016: FD_SET(backchannel, fdsr);
1017: FD_SET(signal_pipe[0], fdsr);
1018: if (errpipe[0] != -1)
1019: FD_SET(errpipe[0], fdsr);
1020: maxfd = MAX(MAX(errpipe[0], signal_pipe[0]), backchannel);
1021:
1022: /* If command exited we just poll, there may be data on errpipe. */
1023: n = select(maxfd + 1, fdsr, NULL, NULL, alive ? NULL : &tv);
1024: if (n <= 0) {
1025: if (n == 0)
1026: goto done;
1.1.1.2 ! misho 1027: if (errno == EINTR || errno == ENOMEM)
1.1 misho 1028: continue;
1.1.1.2 ! misho 1029: warning("monitor: %s", _("select failed"));
! 1030: break;
1.1 misho 1031: }
1032:
1033: if (FD_ISSET(signal_pipe[0], fdsr)) {
1034: n = read(signal_pipe[0], &signo, sizeof(signo));
1035: if (n == -1) {
1036: if (errno == EINTR || errno == EAGAIN)
1037: continue;
1038: warning(_("error reading from signal pipe"));
1039: goto done;
1040: }
1041: /*
1042: * Handle SIGCHLD specially and deliver other signals
1043: * directly to the child.
1044: */
1.1.1.2 ! misho 1045: if (signo == SIGCHLD) {
! 1046: if (!handle_sigchld(backchannel, &cstat))
! 1047: alive = false;
! 1048: } else {
! 1049: deliver_signal(child, signo, false);
! 1050: }
1.1 misho 1051: continue;
1052: }
1053: if (errpipe[0] != -1 && FD_ISSET(errpipe[0], fdsr)) {
1054: /* read errno or EOF from command pipe */
1055: n = read(errpipe[0], &cstat, sizeof(cstat));
1056: if (n == -1) {
1057: if (errno == EINTR)
1058: continue;
1059: warning(_("error reading from pipe"));
1060: goto done;
1061: }
1062: /* Got errno or EOF, either way we are done with errpipe. */
1063: FD_CLR(errpipe[0], fdsr);
1064: close(errpipe[0]);
1065: errpipe[0] = -1;
1066: }
1067: if (FD_ISSET(backchannel, fdsr)) {
1068: struct command_status cstmp;
1069:
1070: /* read command from backchannel, should be a signal */
1071: n = recv(backchannel, &cstmp, sizeof(cstmp), 0);
1072: if (n == -1) {
1073: if (errno == EINTR)
1074: continue;
1075: warning(_("error reading from socketpair"));
1076: goto done;
1077: }
1078: if (cstmp.type != CMD_SIGNO) {
1079: warningx(_("unexpected reply type on backchannel: %d"),
1080: cstmp.type);
1081: continue;
1082: }
1.1.1.2 ! misho 1083: deliver_signal(child, cstmp.val, true);
1.1 misho 1084: }
1085: }
1086:
1087: done:
1088: if (alive) {
1089: /* XXX An error occurred, should send an error back. */
1090: kill(child, SIGKILL);
1091: } else {
1092: /* Send parent status. */
1093: send_status(backchannel, &cstat);
1094: }
1.1.1.2 ! misho 1095: sudo_debug_exit_int(__func__, __FILE__, __LINE__, sudo_debug_subsys, 1);
1.1 misho 1096: _exit(1);
1097:
1098: bad:
1.1.1.2 ! misho 1099: debug_return_int(errno);
1.1 misho 1100: }
1101:
1102: /*
1103: * Flush any output buffered in iobufs or readable from the fds.
1104: * Does not read from /dev/tty.
1105: */
1106: static void
1107: flush_output(void)
1108: {
1109: struct io_buffer *iob;
1110: struct timeval tv;
1111: fd_set *fdsr, *fdsw;
1112: int nready, nwriters, maxfd = -1;
1.1.1.2 ! misho 1113: debug_decl(flush_output, SUDO_DEBUG_EXEC);
1.1 misho 1114:
1115: /* Determine maxfd */
1116: for (iob = iobufs; iob; iob = iob->next) {
1117: if (iob->rfd > maxfd)
1118: maxfd = iob->rfd;
1119: if (iob->wfd > maxfd)
1120: maxfd = iob->wfd;
1121: }
1122: if (maxfd == -1)
1.1.1.2 ! misho 1123: debug_return;
1.1 misho 1124:
1.1.1.2 ! misho 1125: fdsr = emalloc2(howmany(maxfd + 1, NFDBITS), sizeof(fd_mask));
! 1126: fdsw = emalloc2(howmany(maxfd + 1, NFDBITS), sizeof(fd_mask));
1.1 misho 1127: for (;;) {
1.1.1.2 ! misho 1128: memset(fdsw, 0, howmany(maxfd + 1, NFDBITS) * sizeof(fd_mask));
! 1129: memset(fdsr, 0, howmany(maxfd + 1, NFDBITS) * sizeof(fd_mask));
1.1 misho 1130:
1131: nwriters = 0;
1132: for (iob = iobufs; iob; iob = iob->next) {
1133: /* Don't read from /dev/tty while flushing. */
1134: if (io_fds[SFD_USERTTY] != -1 && iob->rfd == io_fds[SFD_USERTTY])
1135: continue;
1136: if (iob->rfd == -1 && iob->wfd == -1)
1137: continue;
1138: if (iob->off == iob->len) {
1139: iob->off = iob->len = 0;
1140: /* Forward the EOF from reader to writer. */
1141: if (iob->rfd == -1) {
1142: safe_close(iob->wfd);
1143: iob->wfd = -1;
1144: }
1145: }
1146: if (iob->rfd != -1) {
1147: if (iob->len != sizeof(iob->buf))
1148: FD_SET(iob->rfd, fdsr);
1149: }
1150: if (iob->wfd != -1) {
1151: if (iob->len > iob->off) {
1152: nwriters++;
1153: FD_SET(iob->wfd, fdsw);
1154: }
1155: }
1156: }
1157:
1158: /* Don't sleep in select if there are no buffers that need writing. */
1159: tv.tv_sec = 0;
1160: tv.tv_usec = 0;
1161: nready = select(maxfd + 1, fdsr, fdsw, NULL, nwriters ? NULL : &tv);
1162: if (nready <= 0) {
1163: if (nready == 0)
1164: break; /* all I/O flushed */
1.1.1.2 ! misho 1165: if (errno == EINTR || errno == ENOMEM)
1.1 misho 1166: continue;
1.1.1.2 ! misho 1167: warning(_("select failed"));
1.1 misho 1168: }
1.1.1.2 ! misho 1169: if (perform_io(fdsr, fdsw, NULL) != 0 || nready == -1)
1.1 misho 1170: break;
1171: }
1172: efree(fdsr);
1173: efree(fdsw);
1.1.1.2 ! misho 1174: debug_return;
1.1 misho 1175: }
1176:
1177: /*
1178: * Sets up std{in,out,err} and executes the actual command.
1179: * Returns only if execve() fails.
1180: */
1181: static void
1.1.1.2 ! misho 1182: exec_pty(struct command_details *details, int *errfd)
1.1 misho 1183: {
1184: pid_t self = getpid();
1.1.1.2 ! misho 1185: debug_decl(exec_pty, SUDO_DEBUG_EXEC);
1.1 misho 1186:
1187: /* Set child process group here too to avoid a race. */
1188: setpgid(0, self);
1189:
1190: /* Wire up standard fds, note that stdout/stderr may be pipes. */
1191: if (dup2(io_fds[SFD_STDIN], STDIN_FILENO) == -1 ||
1192: dup2(io_fds[SFD_STDOUT], STDOUT_FILENO) == -1 ||
1193: dup2(io_fds[SFD_STDERR], STDERR_FILENO) == -1)
1194: error(1, "dup2");
1195:
1196: /* Wait for parent to grant us the tty if we are foreground. */
1197: if (foreground) {
1198: while (tcgetpgrp(io_fds[SFD_SLAVE]) != self)
1199: ; /* spin */
1200: }
1201:
1202: /* We have guaranteed that the slave fd is > 2 */
1203: if (io_fds[SFD_SLAVE] != -1)
1204: close(io_fds[SFD_SLAVE]);
1205: if (io_fds[SFD_STDIN] != io_fds[SFD_SLAVE])
1206: close(io_fds[SFD_STDIN]);
1207: if (io_fds[SFD_STDOUT] != io_fds[SFD_SLAVE])
1208: close(io_fds[SFD_STDOUT]);
1209: if (io_fds[SFD_STDERR] != io_fds[SFD_SLAVE])
1210: close(io_fds[SFD_STDERR]);
1211:
1.1.1.2 ! misho 1212: sudo_debug_execve(SUDO_DEBUG_INFO, details->command,
! 1213: details->argv, details->envp);
! 1214:
! 1215: if (details->closefrom >= 0) {
! 1216: int maxfd = details->closefrom;
! 1217: dup2(*errfd, maxfd);
! 1218: (void)fcntl(maxfd, F_SETFD, FD_CLOEXEC);
! 1219: *errfd = maxfd++;
! 1220: if (sudo_debug_fd_set(maxfd) != -1)
! 1221: maxfd++;
! 1222: closefrom(maxfd);
! 1223: }
1.1 misho 1224: #ifdef HAVE_SELINUX
1.1.1.2 ! misho 1225: if (ISSET(details->flags, CD_RBAC_ENABLED)) {
! 1226: selinux_execve(details->command, details->argv, details->envp,
! 1227: ISSET(details->flags, CD_NOEXEC));
! 1228: } else
1.1 misho 1229: #endif
1.1.1.2 ! misho 1230: {
! 1231: sudo_execve(details->command, details->argv, details->envp,
! 1232: ISSET(details->flags, CD_NOEXEC));
! 1233: }
! 1234: sudo_debug_printf(SUDO_DEBUG_ERROR, "unable to exec %s: %s",
! 1235: details->command, strerror(errno));
! 1236: debug_return;
1.1 misho 1237: }
1238:
1239: /*
1240: * Propagates tty size change signals to pty being used by the command.
1241: */
1242: static void
1243: sync_ttysize(int src, int dst)
1244: {
1245: #ifdef TIOCGWINSZ
1246: struct winsize wsize;
1247: pid_t pgrp;
1.1.1.2 ! misho 1248: debug_decl(sync_ttysize, SUDO_DEBUG_EXEC);
1.1 misho 1249:
1250: if (ioctl(src, TIOCGWINSZ, &wsize) == 0) {
1251: ioctl(dst, TIOCSWINSZ, &wsize);
1252: if ((pgrp = tcgetpgrp(dst)) != -1)
1253: killpg(pgrp, SIGWINCH);
1254: }
1.1.1.2 ! misho 1255:
! 1256: debug_return;
1.1 misho 1257: #endif
1258: }
1259:
1260: /*
1261: * Handler for SIGWINCH in parent.
1262: */
1263: static void
1264: sigwinch(int s)
1265: {
1266: int serrno = errno;
1267:
1268: sync_ttysize(io_fds[SFD_USERTTY], io_fds[SFD_SLAVE]);
1269: errno = serrno;
1270: }
1271:
1272: /*
1273: * Only close the fd if it is not /dev/tty or std{in,out,err}.
1274: * Return value is the same as send(2).
1275: */
1276: static int
1277: safe_close(int fd)
1278: {
1.1.1.2 ! misho 1279: debug_decl(safe_close, SUDO_DEBUG_EXEC);
! 1280:
1.1 misho 1281: /* Avoid closing /dev/tty or std{in,out,err}. */
1282: if (fd < 3 || fd == io_fds[SFD_USERTTY]) {
1283: errno = EINVAL;
1.1.1.2 ! misho 1284: debug_return_int(-1);
1.1 misho 1285: }
1.1.1.2 ! misho 1286: debug_return_int(close(fd));
1.1 misho 1287: }
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