sh/main.c

   1 /*-
   2  * SPDX-License-Identifier: BSD-3-Clause
   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 #ifndef lint
  36 static char const copyright[] =
  37 "@(#) Copyright (c) 1991, 1993\n\
  38         The Regents of the University of California.  All rights reserved.\n";
  39 #endif /* not lint */
  40
  41 #ifndef lint
  42 #if 0
  43 static char sccsid[] = "@(#)main.c      8.6 (Berkeley) 5/28/95";
  44 #endif
  45 #endif /* not lint */
  46 #include <sys/cdefs.h>
  47 __FBSDID("$FreeBSD: head/bin/sh/main.c 326025 2017-11-20 19:49:47Z pfg $");
  48
  49 #include <stdio.h>
  50 #include <signal.h>
  51 #include <sys/stat.h>
  52 #include <unistd.h>
  53 #include <fcntl.h>
  54 #include <locale.h>
  55 #include <errno.h>
  56
  57 #include "shell.h"
  58 #include "main.h"
  59 #include "mail.h"
  60 #include "options.h"
  61 #include "output.h"
  62 #include "parser.h"
  63 #include "nodes.h"
  64 #include "expand.h"
  65 #include "eval.h"
  66 #include "jobs.h"
  67 #include "input.h"
  68 #include "trap.h"
  69 #include "var.h"
  70 #include "show.h"
  71 #include "memalloc.h"
  72 #include "error.h"
  73 #include "mystring.h"
  74 #include "exec.h"
  75 #include "cd.h"
  76 #include "redir.h"
  77 #include "builtins.h"
  78
  79 int rootpid;
  80 int rootshell;
  81 struct jmploc main_handler;
  82 int localeisutf8, initial_localeisutf8;
  83
  84 static void reset(void);
  85 static void cmdloop(int);
  86 static void read_profile(const char *);
  87 static char *find_dot_file(char *);
  88
  89 /*
  90  * Main routine.  We initialize things, parse the arguments, execute
  91  * profiles if we're a login shell, and then call cmdloop to execute
  92  * commands.  The setjmp call sets up the location to jump to when an
  93  * exception occurs.  When an exception occurs the variable "state"
  94  * is used to figure out how far we had gotten.
  95  */
  96
  97 int
  98 main(int argc, char *argv[])
  99 {
 100         struct stackmark smark, smark2;
 101         volatile int state;
 102         char *shinit;
 103
 104         (void) setlocale(LC_ALL, "");
 105         initcharset();
 106         state = 0;
 107         if (setjmp(main_handler.loc)) {
 108                 switch (exception) {
 109                 case EXEXEC:
 110                         exitstatus = exerrno;
 111                         break;
 112
 113                 case EXERROR:
 114                         exitstatus = 2;
 115                         break;
 116
 117                 default:
 118                         break;
 119                 }
 120
 121                 if (state == 0 || iflag == 0 || ! rootshell ||
 122                     exception == EXEXIT)
 123                         exitshell(exitstatus);
 124                 reset();
 125                 if (exception == EXINT)
 126                         out2fmt_flush("\n");
 127                 popstackmark(&smark);
 128                 FORCEINTON;                             /* enable interrupts */
 129                 if (state == 1)
 130                         goto state1;
 131                 else if (state == 2)
 132                         goto state2;
 133                 else if (state == 3)
 134                         goto state3;
 135                 else
 136                         goto state4;
 137         }
 138         handler = &main_handler;
 139 #ifdef DEBUG
 140         opentrace();
 141         trputs("Shell args:  ");  trargs(argv);
 142 #endif
 143         rootpid = getpid();
 144         rootshell = 1;
 145         INTOFF;
 146         initvar();
 147         setstackmark(&smark);
 148         setstackmark(&smark2);
 149         procargs(argc, argv);
 150         pwd_init(iflag);
 151         INTON;
 152         if (iflag)
 153                 chkmail(1);
 154         if (argv[0] && argv[0][0] == '-') {
 155                 state = 1;
 156                 read_profile("/etc/profile");
 157 state1:
 158                 state = 2;
 159                 if (privileged == 0)
 160                         read_profile("${HOME-}/.profile");
 161                 else
 162                         read_profile("/etc/suid_profile");
 163         }
 164 state2:
 165         state = 3;
 166         if (!privileged && iflag) {
 167                 if ((shinit = lookupvar("ENV")) != NULL && *shinit != '\0') {
 168                         state = 3;
 169                         read_profile(shinit);
 170                 }
 171         }
 172 state3:
 173         state = 4;
 174         popstackmark(&smark2);
 175         if (minusc) {
 176                 evalstring(minusc, sflag ? 0 : EV_EXIT);
 177         }
 178 state4:
 179         if (sflag || minusc == NULL) {
 180                 cmdloop(1);
 181         }
 182         exitshell(exitstatus);
 183         /*NOTREACHED*/
 184         return 0;
 185 }
 186
 187 static void
 188 reset(void)
 189 {
 190         reseteval();
 191         resetinput();
 192 }
 193
 194 /*
 195  * Read and execute commands.  "Top" is nonzero for the top level command
 196  * loop; it turns on prompting if the shell is interactive.
 197  */
 198
 199 static void
 200 cmdloop(int top)
 201 {
 202         union node *n;
 203         struct stackmark smark;
 204         int inter;
 205         int numeof = 0;
 206
 207         TRACE(("cmdloop(%d) called\n", top));
 208         setstackmark(&smark);
 209         for (;;) {
 210                 if (pendingsig)
 211                         dotrap();
 212                 inter = 0;
 213                 if (iflag && top) {
 214                         inter++;
 215                         showjobs(1, SHOWJOBS_DEFAULT);
 216                         chkmail(0);
 217                         flushout(&output);
 218                 }
 219                 n = parsecmd(inter);
 220                 /* showtree(n); DEBUG */
 221                 if (n == NEOF) {
 222                         if (!top || numeof >= 50)
 223                                 break;
 224                         if (!stoppedjobs()) {
 225                                 if (!Iflag)
 226                                         break;
 227                                 out2fmt_flush("\nUse \"exit\" to leave shell.\n");
 228                         }
 229                         numeof++;
 230                 } else if (n != NULL && nflag == 0) {
 231                         job_warning = (job_warning == 2) ? 1 : 0;
 232                         numeof = 0;
 233                         evaltree(n, 0);
 234                 }
 235                 popstackmark(&smark);
 236                 setstackmark(&smark);
 237                 if (evalskip != 0) {
 238                         if (evalskip == SKIPRETURN)
 239                                 evalskip = 0;
 240                         break;
 241                 }
 242         }
 243         popstackmark(&smark);
 244 }
 245
 246
 247
 248 /*
 249  * Read /etc/profile or .profile.  Return on error.
 250  */
 251
 252 static void
 253 read_profile(const char *name)
 254 {
 255         int fd;
 256         const char *expandedname;
 257
 258         expandedname = expandstr(name);
 259         if (expandedname == NULL)
 260                 return;
 261         INTOFF;
 262         if ((fd = open(expandedname, O_RDONLY | O_CLOEXEC)) >= 0)
 263                 setinputfd(fd, 1);
 264         INTON;
 265         if (fd < 0)
 266                 return;
 267         cmdloop(0);
 268         popfile();
 269 }
 270
 271
 272
 273 /*
 274  * Read a file containing shell functions.
 275  */
 276
 277 void
 278 readcmdfile(const char *name)
 279 {
 280         setinputfile(name, 1);
 281         cmdloop(0);
 282         popfile();
 283 }
 284
 285
 286
 287 /*
 288  * Take commands from a file.  To be compatible we should do a path
 289  * search for the file, which is necessary to find sub-commands.
 290  */
 291
 292
 293 static char *
 294 find_dot_file(char *basename)
 295 {
 296         char *fullname;
 297         const char *path = pathval();
 298         struct stat statb;
 299
 300         /* don't try this for absolute or relative paths */
 301         if( strchr(basename, '/'))
 302                 return basename;
 303
 304         while ((fullname = padvance(&path, basename)) != NULL) {
 305                 if ((stat(fullname, &statb) == 0) && S_ISREG(statb.st_mode)) {
 306                         /*
 307                          * Don't bother freeing here, since it will
 308                          * be freed by the caller.
 309                          */
 310                         return fullname;
 311                 }
 312                 stunalloc(fullname);
 313         }
 314         return basename;
 315 }
 316
 317 int
 318 dotcmd(int argc, char **argv)
 319 {
 320         char *filename, *fullname;
 321
 322         if (argc < 2)
 323                 error("missing filename");
 324
 325         exitstatus = 0;
 326
 327         /*
 328          * Because we have historically not supported any options,
 329          * only treat "--" specially.
 330          */
 331         filename = argc > 2 && strcmp(argv[1], "--") == 0 ? argv[2] : argv[1];
 332
 333         fullname = find_dot_file(filename);
 334         setinputfile(fullname, 1);
 335         commandname = fullname;
 336         cmdloop(0);
 337         popfile();
 338         return exitstatus;
 339 }
 340
 341
 342 int
 343 exitcmd(int argc, char **argv)
 344 {
 345         if (stoppedjobs())
 346                 return 0;
 347         if (argc > 1)
 348                 exitshell(number(argv[1]));
 349         else
 350                 exitshell_savedstatus();
 351 }