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1 | #define _XOPEN_SOURCE |
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2 | #define _XOPEN_SOURCE_EXTENDED |
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3 | #include <features.h> |
4 | |
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5 | #include <stdio.h> |
6 | #include <stdlib.h> |
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7 | #include <string.h> |
8 | #include <unistd.h> |
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9 | #include <signal.h> |
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10 | #include <fcntl.h> |
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11 | #include <termios.h> |
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12 | #include <grp.h> |
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13 | #include <utmp.h> |
14 | #include <pwd.h> |
15 | #include <time.h> |
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16 | #include <sys/types.h> |
17 | #include <sys/wait.h> |
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18 | #include <sys/ioctl.h> |
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19 | |
20 | #include "putty.h" |
21 | |
22 | #ifndef FALSE |
23 | #define FALSE 0 |
24 | #endif |
25 | #ifndef TRUE |
26 | #define TRUE 1 |
27 | #endif |
28 | |
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29 | #ifndef UTMP_FILE |
30 | #define UTMP_FILE "/var/run/utmp" |
31 | #endif |
32 | #ifndef WTMP_FILE |
33 | #define WTMP_FILE "/var/log/wtmp" |
34 | #endif |
35 | #ifndef LASTLOG_FILE |
36 | #ifdef _PATH_LASTLOG |
37 | #define LASTLOG_FILE _PATH_LASTLOG |
38 | #else |
39 | #define LASTLOG_FILE "/var/log/lastlog" |
40 | #endif |
41 | #endif |
42 | |
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43 | /* |
44 | * Set up a default for vaguely sane systems. The idea is that if |
45 | * OMIT_UTMP is not defined, then at least one of the symbols which |
46 | * enable particular forms of utmp processing should be, if only so |
47 | * that a link error can warn you that you should have defined |
48 | * OMIT_UTMP if you didn't want any. Currently HAVE_PUTUTLINE is |
49 | * the only such symbol. |
50 | */ |
51 | #ifndef OMIT_UTMP |
52 | #if !defined HAVE_PUTUTLINE |
53 | #define HAVE_PUTUTLINE |
54 | #endif |
55 | #endif |
56 | |
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57 | int pty_master_fd; |
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58 | static int pty_stamped_utmp = 0; |
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59 | static int pty_child_pid; |
60 | static sig_atomic_t pty_child_dead; |
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61 | #ifndef OMIT_UTMP |
62 | static struct utmp utmp_entry; |
63 | #endif |
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64 | char **pty_argv; |
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65 | |
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66 | int pty_child_is_dead(void) |
67 | { |
68 | return pty_child_dead; |
69 | } |
70 | |
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71 | static void pty_size(void); |
72 | |
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73 | static void setup_utmp(char *ttyname) |
74 | { |
75 | #ifndef OMIT_UTMP |
76 | #ifdef HAVE_LASTLOG |
77 | struct lastlog lastlog_entry; |
78 | FILE *lastlog; |
79 | #endif |
80 | struct passwd *pw; |
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81 | char *location; |
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82 | FILE *wtmp; |
83 | |
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84 | if (!cfg.stamp_utmp) |
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85 | return; |
86 | |
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87 | pw = getpwuid(getuid()); |
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88 | location = get_x_display(); |
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89 | memset(&utmp_entry, 0, sizeof(utmp_entry)); |
90 | utmp_entry.ut_type = USER_PROCESS; |
91 | utmp_entry.ut_pid = getpid(); |
92 | strncpy(utmp_entry.ut_line, ttyname+5, lenof(utmp_entry.ut_line)); |
93 | strncpy(utmp_entry.ut_id, ttyname+8, lenof(utmp_entry.ut_id)); |
94 | strncpy(utmp_entry.ut_user, pw->pw_name, lenof(utmp_entry.ut_user)); |
95 | strncpy(utmp_entry.ut_host, location, lenof(utmp_entry.ut_host)); |
96 | time(&utmp_entry.ut_time); |
97 | |
98 | #if defined HAVE_PUTUTLINE |
99 | utmpname(UTMP_FILE); |
100 | setutent(); |
101 | pututline(&utmp_entry); |
102 | endutent(); |
103 | #endif |
104 | |
105 | if ((wtmp = fopen(WTMP_FILE, "a")) != NULL) { |
106 | fwrite(&utmp_entry, 1, sizeof(utmp_entry), wtmp); |
107 | fclose(wtmp); |
108 | } |
109 | |
110 | #ifdef HAVE_LASTLOG |
111 | memset(&lastlog_entry, 0, sizeof(lastlog_entry)); |
112 | strncpy(lastlog_entry.ll_line, ttyname+5, lenof(lastlog_entry.ll_line)); |
113 | strncpy(lastlog_entry.ll_host, location, lenof(lastlog_entry.ll_host)); |
114 | time(&lastlog_entry.ll_time); |
115 | if ((lastlog = fopen(LASTLOG_FILE, "r+")) != NULL) { |
116 | fseek(lastlog, sizeof(lastlog_entry) * getuid(), SEEK_SET); |
117 | fwrite(&lastlog_entry, 1, sizeof(lastlog_entry), lastlog); |
118 | fclose(lastlog); |
119 | } |
120 | #endif |
121 | |
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122 | pty_stamped_utmp = 1; |
123 | |
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124 | #endif |
125 | } |
126 | |
127 | static void cleanup_utmp(void) |
128 | { |
129 | #ifndef OMIT_UTMP |
130 | FILE *wtmp; |
131 | |
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132 | if (!cfg.stamp_utmp || !pty_stamped_utmp) |
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133 | return; |
134 | |
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135 | utmp_entry.ut_type = DEAD_PROCESS; |
136 | memset(utmp_entry.ut_user, 0, lenof(utmp_entry.ut_user)); |
137 | time(&utmp_entry.ut_time); |
138 | |
139 | if ((wtmp = fopen(WTMP_FILE, "a")) != NULL) { |
140 | fwrite(&utmp_entry, 1, sizeof(utmp_entry), wtmp); |
141 | fclose(wtmp); |
142 | } |
143 | |
144 | memset(utmp_entry.ut_line, 0, lenof(utmp_entry.ut_line)); |
145 | utmp_entry.ut_time = 0; |
146 | |
147 | #if defined HAVE_PUTUTLINE |
148 | utmpname(UTMP_FILE); |
149 | setutent(); |
150 | pututline(&utmp_entry); |
151 | endutent(); |
152 | #endif |
153 | |
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154 | pty_stamped_utmp = 0; /* ensure we never double-cleanup */ |
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155 | #endif |
156 | } |
157 | |
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158 | static void sigchld_handler(int signum) |
159 | { |
160 | pid_t pid; |
161 | int status; |
162 | pid = waitpid(-1, &status, WNOHANG); |
163 | if (pid == pty_child_pid && (WIFEXITED(status) || WIFSIGNALED(status))) |
164 | pty_child_dead = TRUE; |
165 | } |
166 | |
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167 | static void fatal_sig_handler(int signum) |
168 | { |
169 | signal(signum, SIG_DFL); |
170 | cleanup_utmp(); |
171 | setuid(getuid()); |
172 | raise(signum); |
173 | } |
174 | |
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175 | /* |
176 | * Called to set up the pty. |
177 | * |
178 | * Returns an error message, or NULL on success. |
179 | * |
180 | * Also places the canonical host name into `realhost'. It must be |
181 | * freed by the caller. |
182 | */ |
183 | static char *pty_init(char *host, int port, char **realhost, int nodelay) |
184 | { |
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185 | int slavefd; |
186 | char name[FILENAME_MAX]; |
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187 | pid_t pid, pgrp; |
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188 | |
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189 | #ifdef BSD_PTYS |
190 | { |
191 | const char chars1[] = "pqrstuvwxyz"; |
192 | const char chars2[] = "0123456789abcdef"; |
193 | const char *p1, *p2; |
194 | char master_name[20]; |
195 | |
196 | for (p1 = chars1; *p1; p1++) |
197 | for (p2 = chars2; *p2; p2++) { |
198 | sprintf(master_name, "/dev/pty%c%c", *p1, *p2); |
199 | pty_master_fd = open(master_name, O_RDWR); |
200 | if (pty_master_fd >= 0) { |
201 | if (geteuid() == 0 || |
202 | access(master_name, R_OK | W_OK) == 0) |
203 | goto got_one; |
204 | close(pty_master_fd); |
205 | } |
206 | } |
207 | |
208 | /* If we get here, we couldn't get a tty at all. */ |
209 | fprintf(stderr, "pterm: unable to open a pseudo-terminal device\n"); |
210 | exit(1); |
211 | |
212 | got_one: |
213 | strcpy(name, master_name); |
214 | name[5] = 't'; /* /dev/ptyXX -> /dev/ttyXX */ |
215 | } |
216 | #else |
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217 | pty_master_fd = open("/dev/ptmx", O_RDWR); |
218 | |
219 | if (pty_master_fd < 0) { |
220 | perror("/dev/ptmx: open"); |
221 | exit(1); |
222 | } |
223 | |
224 | if (grantpt(pty_master_fd) < 0) { |
225 | perror("grantpt"); |
226 | exit(1); |
227 | } |
228 | |
229 | if (unlockpt(pty_master_fd) < 0) { |
230 | perror("unlockpt"); |
231 | exit(1); |
232 | } |
233 | |
234 | name[FILENAME_MAX-1] = '\0'; |
235 | strncpy(name, ptsname(pty_master_fd), FILENAME_MAX-1); |
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236 | #endif |
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237 | |
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238 | /* |
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239 | * Trap as many fatal signals as we can in the hope of having |
240 | * the best chance to clean up utmp before termination. |
241 | */ |
242 | signal(SIGHUP, fatal_sig_handler); |
243 | signal(SIGINT, fatal_sig_handler); |
244 | signal(SIGQUIT, fatal_sig_handler); |
245 | signal(SIGILL, fatal_sig_handler); |
246 | signal(SIGABRT, fatal_sig_handler); |
247 | signal(SIGFPE, fatal_sig_handler); |
248 | signal(SIGPIPE, fatal_sig_handler); |
249 | signal(SIGALRM, fatal_sig_handler); |
250 | signal(SIGTERM, fatal_sig_handler); |
251 | signal(SIGSEGV, fatal_sig_handler); |
252 | signal(SIGUSR1, fatal_sig_handler); |
253 | signal(SIGUSR2, fatal_sig_handler); |
254 | #ifdef SIGBUS |
255 | signal(SIGBUS, fatal_sig_handler); |
256 | #endif |
257 | #ifdef SIGPOLL |
258 | signal(SIGPOLL, fatal_sig_handler); |
259 | #endif |
260 | #ifdef SIGPROF |
261 | signal(SIGPROF, fatal_sig_handler); |
262 | #endif |
263 | #ifdef SIGSYS |
264 | signal(SIGSYS, fatal_sig_handler); |
265 | #endif |
266 | #ifdef SIGTRAP |
267 | signal(SIGTRAP, fatal_sig_handler); |
268 | #endif |
269 | #ifdef SIGVTALRM |
270 | signal(SIGVTALRM, fatal_sig_handler); |
271 | #endif |
272 | #ifdef SIGXCPU |
273 | signal(SIGXCPU, fatal_sig_handler); |
274 | #endif |
275 | #ifdef SIGXFSZ |
276 | signal(SIGXFSZ, fatal_sig_handler); |
277 | #endif |
278 | #ifdef SIGIO |
279 | signal(SIGIO, fatal_sig_handler); |
280 | #endif |
281 | /* Also clean up utmp on normal exit. */ |
282 | atexit(cleanup_utmp); |
283 | setup_utmp(name); |
284 | |
285 | /* |
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286 | * Fork and execute the command. |
287 | */ |
288 | pid = fork(); |
289 | if (pid < 0) { |
290 | perror("fork"); |
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291 | exit(1); |
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292 | } |
293 | |
294 | if (pid == 0) { |
295 | int i; |
296 | /* |
297 | * We are the child. |
298 | */ |
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299 | |
300 | slavefd = open(name, O_RDWR); |
301 | if (slavefd < 0) { |
302 | perror("slave pty: open"); |
303 | exit(1); |
304 | } |
305 | |
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306 | #ifdef BSD_PTYS |
307 | /* We need to chown/chmod the /dev/ttyXX device. */ |
308 | { |
309 | struct group *gp = getgrnam("tty"); |
310 | fchown(slavefd, getuid(), gp ? gp->gr_gid : -1); |
311 | fchmod(slavefd, 0600); |
312 | } |
313 | #endif |
314 | |
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315 | close(pty_master_fd); |
316 | close(0); |
317 | close(1); |
318 | close(2); |
319 | fcntl(slavefd, F_SETFD, 0); /* don't close on exec */ |
320 | dup2(slavefd, 0); |
321 | dup2(slavefd, 1); |
322 | dup2(slavefd, 2); |
323 | setsid(); |
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324 | ioctl(slavefd, TIOCSCTTY, 1); |
325 | pgrp = getpid(); |
326 | tcsetpgrp(slavefd, pgrp); |
327 | setpgrp(); |
328 | close(open(name, O_WRONLY, 0)); |
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329 | setpgrp(); |
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330 | /* In case we were setgid-utmp or setuid-root, drop privs. */ |
331 | setgid(getgid()); |
332 | setuid(getuid()); |
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333 | /* Close everything _else_, for tidiness. */ |
334 | for (i = 3; i < 1024; i++) |
335 | close(i); |
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336 | { |
337 | char term_env_var[10 + sizeof(cfg.termtype)]; |
338 | sprintf(term_env_var, "TERM=%s", cfg.termtype); |
339 | putenv(term_env_var); |
340 | } |
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341 | if (pty_argv) |
342 | execvp(pty_argv[0], pty_argv); |
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343 | else { |
344 | char *shell = getenv("SHELL"); |
345 | char *shellname; |
346 | if (cfg.login_shell) { |
347 | char *p = strrchr(shell, '/'); |
348 | shellname = smalloc(2+strlen(shell)); |
349 | p = p ? p+1 : shell; |
350 | sprintf(shellname, "-%s", p); |
351 | } else |
352 | shellname = shell; |
353 | execl(getenv("SHELL"), shellname, NULL); |
354 | } |
355 | |
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356 | /* |
357 | * If we're here, exec has gone badly foom. |
358 | */ |
359 | perror("exec"); |
360 | exit(127); |
361 | } else { |
362 | close(slavefd); |
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363 | pty_child_pid = pid; |
364 | pty_child_dead = FALSE; |
365 | signal(SIGCHLD, sigchld_handler); |
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366 | } |
367 | |
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368 | return NULL; |
369 | } |
370 | |
371 | /* |
372 | * Called to send data down the pty. |
373 | */ |
374 | static int pty_send(char *buf, int len) |
375 | { |
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376 | while (len > 0) { |
377 | int ret = write(pty_master_fd, buf, len); |
378 | if (ret < 0) { |
379 | perror("write pty master"); |
380 | exit(1); |
381 | } |
382 | buf += ret; |
383 | len -= ret; |
384 | } |
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385 | return 0; |
386 | } |
387 | |
388 | /* |
389 | * Called to query the current socket sendability status. |
390 | */ |
391 | static int pty_sendbuffer(void) |
392 | { |
393 | return 0; |
394 | } |
395 | |
396 | /* |
397 | * Called to set the size of the window |
398 | */ |
399 | static void pty_size(void) |
400 | { |
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401 | struct winsize size; |
402 | |
403 | size.ws_row = (unsigned short)rows; |
404 | size.ws_col = (unsigned short)cols; |
405 | ioctl(pty_master_fd, TIOCSWINSZ, (void *)&size); |
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406 | return; |
407 | } |
408 | |
409 | /* |
410 | * Send special codes. |
411 | */ |
412 | static void pty_special(Telnet_Special code) |
413 | { |
414 | /* Do nothing! */ |
415 | return; |
416 | } |
417 | |
418 | static Socket pty_socket(void) |
419 | { |
420 | return NULL; /* shouldn't ever be needed */ |
421 | } |
422 | |
423 | static int pty_sendok(void) |
424 | { |
425 | return 1; |
426 | } |
427 | |
428 | static void pty_unthrottle(int backlog) |
429 | { |
430 | /* do nothing */ |
431 | } |
432 | |
433 | static int pty_ldisc(int option) |
434 | { |
435 | return 0; /* neither editing nor echoing */ |
436 | } |
437 | |
438 | static int pty_exitcode(void) |
439 | { |
440 | /* Shouldn't ever be required */ |
441 | return 0; |
442 | } |
443 | |
444 | Backend pty_backend = { |
445 | pty_init, |
446 | pty_send, |
447 | pty_sendbuffer, |
448 | pty_size, |
449 | pty_special, |
450 | pty_socket, |
451 | pty_exitcode, |
452 | pty_sendok, |
453 | pty_ldisc, |
454 | pty_unthrottle, |
455 | 1 |
456 | }; |