1 /* $NetBSD: main.c,v 1.72 2017/07/05 20:00:27 kre Exp $ */ 2 3 /*- 4 * Copyright (c) 1991, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * This code is derived from software contributed to Berkeley by 8 * Kenneth Almquist. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 */ 34 35 #include <sys/cdefs.h> 36 #ifndef lint 37 __COPYRIGHT("@(#) Copyright (c) 1991, 1993\ 38 The Regents of the University of California. All rights reserved."); 39 #endif /* not lint */ 40 41 #ifndef lint 42 #if 0 43 static char sccsid[] = "@(#)main.c 8.7 (Berkeley) 7/19/95"; 44 #else 45 __RCSID("$NetBSD: main.c,v 1.72 2017/07/05 20:00:27 kre Exp $"); 46 #endif 47 #endif /* not lint */ 48 49 #include <errno.h> 50 #include <stdio.h> 51 #include <signal.h> 52 #include <sys/stat.h> 53 #include <unistd.h> 54 #include <stdlib.h> 55 #include <locale.h> 56 #include <fcntl.h> 57 58 59 #include "shell.h" 60 #include "main.h" 61 #include "mail.h" 62 #include "options.h" 63 #include "builtins.h" 64 #include "output.h" 65 #include "parser.h" 66 #include "nodes.h" 67 #include "expand.h" 68 #include "eval.h" 69 #include "jobs.h" 70 #include "input.h" 71 #include "trap.h" 72 #include "var.h" 73 #include "show.h" 74 #include "memalloc.h" 75 #include "error.h" 76 #include "init.h" 77 #include "mystring.h" 78 #include "exec.h" 79 #include "cd.h" 80 #include "redir.h" 81 82 #define PROFILE 0 83 84 int rootpid; 85 int rootshell; 86 int max_user_fd; 87 #if PROFILE 88 short profile_buf[16384]; 89 extern int etext(); 90 #endif 91 92 STATIC void read_profile(const char *); 93 int main(int, char **); 94 95 /* 96 * Main routine. We initialize things, parse the arguments, execute 97 * profiles if we're a login shell, and then call cmdloop to execute 98 * commands. The setjmp call sets up the location to jump to when an 99 * exception occurs. When an exception occurs the variable "state" 100 * is used to figure out how far we had gotten. 101 */ 102 103 int 104 main(int argc, char **argv) 105 { 106 struct jmploc jmploc; 107 struct stackmark smark; 108 volatile int state; 109 char *shinit; 110 uid_t uid; 111 gid_t gid; 112 113 uid = getuid(); 114 gid = getgid(); 115 116 max_user_fd = fcntl(0, F_MAXFD); 117 if (max_user_fd < 2) 118 max_user_fd = 2; 119 120 setlocale(LC_ALL, ""); 121 122 posix = getenv("POSIXLY_CORRECT") != NULL; 123 #if PROFILE 124 monitor(4, etext, profile_buf, sizeof profile_buf, 50); 125 #endif 126 state = 0; 127 if (setjmp(jmploc.loc)) { 128 /* 129 * When a shell procedure is executed, we raise the 130 * exception EXSHELLPROC to clean up before executing 131 * the shell procedure. 132 */ 133 switch (exception) { 134 case EXSHELLPROC: 135 rootpid = getpid(); 136 rootshell = 1; 137 minusc = NULL; 138 state = 3; 139 break; 140 141 case EXEXEC: 142 exitstatus = exerrno; 143 break; 144 145 case EXERROR: 146 exitstatus = 2; 147 break; 148 149 default: 150 break; 151 } 152 153 if (exception != EXSHELLPROC) { 154 if (state == 0 || iflag == 0 || ! rootshell) 155 exitshell(exitstatus); 156 } 157 reset(); 158 if (exception == EXINT) { 159 out2c('\n'); 160 flushout(&errout); 161 } 162 popstackmark(&smark); 163 FORCEINTON; /* enable interrupts */ 164 if (state == 1) 165 goto state1; 166 else if (state == 2) 167 goto state2; 168 else if (state == 3) 169 goto state3; 170 else 171 goto state4; 172 } 173 handler = &jmploc; 174 #ifdef DEBUG 175 #if DEBUG >= 2 176 debug = 1; /* this may be reset by procargs() later */ 177 #endif 178 opentrace(); 179 trputs("Shell args: "); trargs(argv); 180 #if DEBUG >= 3 181 set_debug(((DEBUG)==3 ? "_@" : "++"), 1); 182 #endif 183 #endif 184 rootpid = getpid(); 185 rootshell = 1; 186 init(); 187 initpwd(); 188 setstackmark(&smark); 189 procargs(argc, argv); 190 191 /* 192 * Limit bogus system(3) or popen(3) calls in setuid binaries, 193 * by requiring the -p flag 194 */ 195 if (!pflag && (uid != geteuid() || gid != getegid())) { 196 setuid(uid); 197 setgid(gid); 198 /* PS1 might need to be changed accordingly. */ 199 choose_ps1(); 200 } 201 202 if (argv[0] && argv[0][0] == '-') { 203 state = 1; 204 read_profile("/etc/profile"); 205 state1: 206 state = 2; 207 read_profile(".profile"); 208 } 209 state2: 210 state = 3; 211 if ((iflag || !posix) && 212 getuid() == geteuid() && getgid() == getegid()) { 213 if ((shinit = lookupvar("ENV")) != NULL && *shinit != '\0') { 214 state = 3; 215 read_profile(shinit); 216 } 217 } 218 state3: 219 state = 4; 220 line_number = 1; /* undo anything from profile files */ 221 222 if (sflag == 0 || minusc) { 223 static int sigs[] = { 224 SIGINT, SIGQUIT, SIGHUP, 225 #ifdef SIGTSTP 226 SIGTSTP, 227 #endif 228 SIGPIPE 229 }; 230 #define SIGSSIZE (sizeof(sigs)/sizeof(sigs[0])) 231 size_t i; 232 233 for (i = 0; i < SIGSSIZE; i++) 234 setsignal(sigs[i], 0); 235 } 236 237 if (minusc) 238 evalstring(minusc, 0); 239 240 if (sflag || minusc == NULL) { 241 state4: /* XXX ??? - why isn't this before the "if" statement */ 242 cmdloop(1); 243 } 244 #if PROFILE 245 monitor(0); 246 #endif 247 exitshell(exitstatus); 248 /* NOTREACHED */ 249 } 250 251 252 /* 253 * Read and execute commands. "Top" is nonzero for the top level command 254 * loop; it turns on prompting if the shell is interactive. 255 */ 256 257 void 258 cmdloop(int top) 259 { 260 union node *n; 261 struct stackmark smark; 262 int inter; 263 int numeof = 0; 264 enum skipstate skip; 265 266 CTRACE(DBG_ALWAYS, ("cmdloop(%d) called\n", top)); 267 setstackmark(&smark); 268 for (;;) { 269 if (pendingsigs) 270 dotrap(); 271 inter = 0; 272 if (iflag == 1 && top) { 273 inter = 1; 274 showjobs(out2, SHOW_CHANGED); 275 chkmail(0); 276 flushout(&errout); 277 nflag = 0; 278 } 279 n = parsecmd(inter); 280 VXTRACE(DBG_PARSE|DBG_EVAL|DBG_CMDS,("cmdloop: "),showtree(n)); 281 if (n == NEOF) { 282 if (!top || numeof >= 50) 283 break; 284 if (nflag) 285 break; 286 if (!stoppedjobs()) { 287 if (!iflag || !Iflag) 288 break; 289 out2str("\nUse \"exit\" to leave shell.\n"); 290 } 291 numeof++; 292 } else if (n != NULL && nflag == 0) { 293 job_warning = (job_warning == 2) ? 1 : 0; 294 numeof = 0; 295 evaltree(n, EV_MORE); 296 } 297 popstackmark(&smark); 298 setstackmark(&smark); 299 300 /* 301 * Any SKIP* can occur here! SKIP(FUNC|BREAK|CONT) occur when 302 * a dotcmd is in a loop or a function body and appropriate 303 * built-ins occurs in file scope in the sourced file. Values 304 * other than SKIPFILE are reset by the appropriate eval*() 305 * that contained the dotcmd() call. 306 */ 307 skip = current_skipstate(); 308 if (skip != SKIPNONE) { 309 if (skip == SKIPFILE) 310 stop_skipping(); 311 break; 312 } 313 } 314 popstackmark(&smark); 315 } 316 317 318 319 /* 320 * Read /etc/profile or .profile. Return on error. 321 */ 322 323 STATIC void 324 read_profile(const char *name) 325 { 326 int fd; 327 int xflag_set = 0; 328 int vflag_set = 0; 329 330 INTOFF; 331 if ((fd = open(name, O_RDONLY)) >= 0) 332 setinputfd(fd, 1); 333 INTON; 334 if (fd < 0) 335 return; 336 /* -q turns off -x and -v just when executing init files */ 337 if (qflag) { 338 if (xflag) 339 xflag = 0, xflag_set = 1; 340 if (vflag) 341 vflag = 0, vflag_set = 1; 342 } 343 cmdloop(0); 344 if (qflag) { 345 if (xflag_set) 346 xflag = 1; 347 if (vflag_set) 348 vflag = 1; 349 } 350 popfile(); 351 } 352 353 354 355 /* 356 * Read a file containing shell functions. 357 */ 358 359 void 360 readcmdfile(char *name) 361 { 362 int fd; 363 364 INTOFF; 365 if ((fd = open(name, O_RDONLY)) >= 0) 366 setinputfd(fd, 1); 367 else 368 error("Can't open %s", name); 369 INTON; 370 cmdloop(0); 371 popfile(); 372 } 373 374 375 376 int 377 exitcmd(int argc, char **argv) 378 { 379 if (stoppedjobs()) 380 return 0; 381 if (argc > 1) 382 exitstatus = number(argv[1]); 383 exitshell(exitstatus); 384 /* NOTREACHED */ 385 } 386