1 /* $NetBSD: main.c,v 1.73 2018/01/23 22:12:52 sevan 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 1.73 2018/01/23 22:12:52 sevan 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 94 /* 95 * Main routine. We initialize things, parse the arguments, execute 96 * profiles if we're a login shell, and then call cmdloop to execute 97 * commands. The setjmp call sets up the location to jump to when an 98 * exception occurs. When an exception occurs the variable "state" 99 * is used to figure out how far we had gotten. 100 */ 101 102 int 103 main(int argc, char **argv) 104 { 105 struct jmploc jmploc; 106 struct stackmark smark; 107 volatile int state; 108 char *shinit; 109 uid_t uid; 110 gid_t gid; 111 112 uid = getuid(); 113 gid = getgid(); 114 115 max_user_fd = fcntl(0, F_MAXFD); 116 if (max_user_fd < 2) 117 max_user_fd = 2; 118 119 setlocale(LC_ALL, ""); 120 121 posix = getenv("POSIXLY_CORRECT") != NULL; 122 #if PROFILE 123 monitor(4, etext, profile_buf, sizeof profile_buf, 50); 124 #endif 125 state = 0; 126 if (setjmp(jmploc.loc)) { 127 /* 128 * When a shell procedure is executed, we raise the 129 * exception EXSHELLPROC to clean up before executing 130 * the shell procedure. 131 */ 132 switch (exception) { 133 case EXSHELLPROC: 134 rootpid = getpid(); 135 rootshell = 1; 136 minusc = NULL; 137 state = 3; 138 break; 139 140 case EXEXEC: 141 exitstatus = exerrno; 142 break; 143 144 case EXERROR: 145 exitstatus = 2; 146 break; 147 148 default: 149 break; 150 } 151 152 if (exception != EXSHELLPROC) { 153 if (state == 0 || iflag == 0 || ! rootshell) 154 exitshell(exitstatus); 155 } 156 reset(); 157 if (exception == EXINT) { 158 out2c('\n'); 159 flushout(&errout); 160 } 161 popstackmark(&smark); 162 FORCEINTON; /* enable interrupts */ 163 if (state == 1) 164 goto state1; 165 else if (state == 2) 166 goto state2; 167 else if (state == 3) 168 goto state3; 169 else 170 goto state4; 171 } 172 handler = &jmploc; 173 #ifdef DEBUG 174 #if DEBUG >= 2 175 debug = 1; /* this may be reset by procargs() later */ 176 #endif 177 opentrace(); 178 trputs("Shell args: "); trargs(argv); 179 #if DEBUG >= 3 180 set_debug(((DEBUG)==3 ? "_@" : "++"), 1); 181 #endif 182 #endif 183 rootpid = getpid(); 184 rootshell = 1; 185 init(); 186 initpwd(); 187 setstackmark(&smark); 188 procargs(argc, argv); 189 190 /* 191 * Limit bogus system(3) or popen(3) calls in setuid binaries, 192 * by requiring the -p flag 193 */ 194 if (!pflag && (uid != geteuid() || gid != getegid())) { 195 setuid(uid); 196 setgid(gid); 197 /* PS1 might need to be changed accordingly. */ 198 choose_ps1(); 199 } 200 201 if (argv[0] && argv[0][0] == '-') { 202 state = 1; 203 read_profile("/etc/profile"); 204 state1: 205 state = 2; 206 read_profile(".profile"); 207 } 208 state2: 209 state = 3; 210 if ((iflag || !posix) && 211 getuid() == geteuid() && getgid() == getegid()) { 212 if ((shinit = lookupvar("ENV")) != NULL && *shinit != '\0') { 213 state = 3; 214 read_profile(shinit); 215 } 216 } 217 state3: 218 state = 4; 219 line_number = 1; /* undo anything from profile files */ 220 221 if (sflag == 0 || minusc) { 222 static int sigs[] = { 223 SIGINT, SIGQUIT, SIGHUP, 224 #ifdef SIGTSTP 225 SIGTSTP, 226 #endif 227 SIGPIPE 228 }; 229 #define SIGSSIZE (sizeof(sigs)/sizeof(sigs[0])) 230 size_t i; 231 232 for (i = 0; i < SIGSSIZE; i++) 233 setsignal(sigs[i], 0); 234 } 235 236 if (minusc) 237 evalstring(minusc, 0); 238 239 if (sflag || minusc == NULL) { 240 state4: /* XXX ??? - why isn't this before the "if" statement */ 241 cmdloop(1); 242 } 243 #if PROFILE 244 monitor(0); 245 #endif 246 exitshell(exitstatus); 247 /* NOTREACHED */ 248 } 249 250 251 /* 252 * Read and execute commands. "Top" is nonzero for the top level command 253 * loop; it turns on prompting if the shell is interactive. 254 */ 255 256 void 257 cmdloop(int top) 258 { 259 union node *n; 260 struct stackmark smark; 261 int inter; 262 int numeof = 0; 263 enum skipstate skip; 264 265 CTRACE(DBG_ALWAYS, ("cmdloop(%d) called\n", top)); 266 setstackmark(&smark); 267 for (;;) { 268 if (pendingsigs) 269 dotrap(); 270 inter = 0; 271 if (iflag == 1 && top) { 272 inter = 1; 273 showjobs(out2, SHOW_CHANGED); 274 chkmail(0); 275 flushout(&errout); 276 nflag = 0; 277 } 278 n = parsecmd(inter); 279 VXTRACE(DBG_PARSE|DBG_EVAL|DBG_CMDS,("cmdloop: "),showtree(n)); 280 if (n == NEOF) { 281 if (!top || numeof >= 50) 282 break; 283 if (nflag) 284 break; 285 if (!stoppedjobs()) { 286 if (!iflag || !Iflag) 287 break; 288 out2str("\nUse \"exit\" to leave shell.\n"); 289 } 290 numeof++; 291 } else if (n != NULL && nflag == 0) { 292 job_warning = (job_warning == 2) ? 1 : 0; 293 numeof = 0; 294 evaltree(n, EV_MORE); 295 } 296 popstackmark(&smark); 297 setstackmark(&smark); 298 299 /* 300 * Any SKIP* can occur here! SKIP(FUNC|BREAK|CONT) occur when 301 * a dotcmd is in a loop or a function body and appropriate 302 * built-ins occurs in file scope in the sourced file. Values 303 * other than SKIPFILE are reset by the appropriate eval*() 304 * that contained the dotcmd() call. 305 */ 306 skip = current_skipstate(); 307 if (skip != SKIPNONE) { 308 if (skip == SKIPFILE) 309 stop_skipping(); 310 break; 311 } 312 } 313 popstackmark(&smark); 314 } 315 316 317 318 /* 319 * Read /etc/profile or .profile. Return on error. 320 */ 321 322 STATIC void 323 read_profile(const char *name) 324 { 325 int fd; 326 int xflag_set = 0; 327 int vflag_set = 0; 328 329 INTOFF; 330 if ((fd = open(name, O_RDONLY)) >= 0) 331 setinputfd(fd, 1); 332 INTON; 333 if (fd < 0) 334 return; 335 /* -q turns off -x and -v just when executing init files */ 336 if (qflag) { 337 if (xflag) 338 xflag = 0, xflag_set = 1; 339 if (vflag) 340 vflag = 0, vflag_set = 1; 341 } 342 cmdloop(0); 343 if (qflag) { 344 if (xflag_set) 345 xflag = 1; 346 if (vflag_set) 347 vflag = 1; 348 } 349 popfile(); 350 } 351 352 353 354 /* 355 * Read a file containing shell functions. 356 */ 357 358 void 359 readcmdfile(char *name) 360 { 361 int fd; 362 363 INTOFF; 364 if ((fd = open(name, O_RDONLY)) >= 0) 365 setinputfd(fd, 1); 366 else 367 error("Can't open %s", name); 368 INTON; 369 cmdloop(0); 370 popfile(); 371 } 372 373 374 375 int 376 exitcmd(int argc, char **argv) 377 { 378 if (stoppedjobs()) 379 return 0; 380 if (argc > 1) 381 exitstatus = number(argv[1]); 382 exitshell(exitstatus); 383 /* NOTREACHED */ 384 } 385