bin/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 #if 0
  37 static char sccsid[] = "@(#)main.c      8.6 (Berkeley) 5/28/95";
  38 #endif
  39 #endif /* not lint */
  40 #include <sys/cdefs.h>
  41 __FBSDID("$FreeBSD: head/bin/sh/main.c 364919 2020-08-28 15:35:45Z jilles $");
  42
  43 #include <stdio.h>
  44 #include <signal.h>
  45 #include <sys/stat.h>
  46 #include <unistd.h>
  47 #include <fcntl.h>
  48 #include <locale.h>
  49 #include <errno.h>
  50
  51 #include "shell.h"
  52 #include "main.h"
  53 #include "mail.h"
  54 #include "options.h"
  55 #include "output.h"
  56 #include "parser.h"
  57 #include "nodes.h"
  58 #include "expand.h"
  59 #include "eval.h"
  60 #include "jobs.h"
  61 #include "input.h"
  62 #include "trap.h"
  63 #include "var.h"
  64 #include "show.h"
  65 #include "memalloc.h"
  66 #include "error.h"
  67 #include "mystring.h"
  68 #include "exec.h"
  69 #include "cd.h"
  70 #include "redir.h"
  71 #include "builtins.h"
  72
  73 int rootpid;
  74 int rootshell;
  75 struct jmploc main_handler;
  76 int localeisutf8, initial_localeisutf8;
  77
  78 static void reset(void);
  79 static void cmdloop(int);
  80 static void read_profile(const char *);
  81 static char *find_dot_file(char *);
  82
  83 /*
  84  * Main routine.  We initialize things, parse the arguments, execute
  85  * profiles if we're a login shell, and then call cmdloop to execute
  86  * commands.  The setjmp call sets up the location to jump to when an
  87  * exception occurs.  When an exception occurs the variable "state"
  88  * is used to figure out how far we had gotten.
  89  */
  90
  91 int
  92 main(int argc, char *argv[])
  93 {
  94         struct stackmark smark, smark2;
  95         volatile int state;
  96         char *shinit;
  97
  98         (void) setlocale(LC_ALL, "");
  99         initcharset();
 100         state = 0;
 101         if (setjmp(main_handler.loc)) {
 102                 if (state == 0 || iflag == 0 || ! rootshell ||
 103                     exception == EXEXIT)
 104                         exitshell(exitstatus);
 105                 reset();
 106                 if (exception == EXINT)
 107                         out2fmt_flush("\n");
 108                 popstackmark(&smark);
 109                 FORCEINTON;                             /* enable interrupts */
 110                 if (state == 1)
 111                         goto state1;
 112                 else if (state == 2)
 113                         goto state2;
 114                 else if (state == 3)
 115                         goto state3;
 116                 else
 117                         goto state4;
 118         }
 119         handler = &main_handler;
 120 #ifdef DEBUG
 121         opentrace();
 122         trputs("Shell args:  ");  trargs(argv);
 123 #endif
 124         rootpid = getpid();
 125         rootshell = 1;
 126         INTOFF;
 127         initvar();
 128         setstackmark(&smark);
 129         setstackmark(&smark2);
 130         procargs(argc, argv);
 131         trap_init();
 132         pwd_init(iflag);
 133         INTON;
 134         if (iflag)
 135                 chkmail(1);
 136         if (argv[0] && argv[0][0] == '-') {
 137                 state = 1;
 138                 read_profile("/etc/profile");
 139 state1:
 140                 state = 2;
 141                 if (privileged == 0)
 142                         read_profile("${HOME-}/.profile");
 143                 else
 144                         read_profile("/etc/suid_profile");
 145         }
 146 state2:
 147         state = 3;
 148         if (!privileged && iflag) {
 149                 if ((shinit = lookupvar("ENV")) != NULL && *shinit != '\0') {
 150                         state = 3;
 151                         read_profile(shinit);
 152                 }
 153         }
 154 state3:
 155         state = 4;
 156         popstackmark(&smark2);
 157         if (minusc) {
 158                 evalstring(minusc, sflag ? 0 : EV_EXIT);
 159         }
 160 state4:
 161         if (sflag || minusc == NULL) {
 162                 cmdloop(1);
 163         }
 164         exitshell(exitstatus);
 165         /*NOTREACHED*/
 166         return 0;
 167 }
 168
 169 static void
 170 reset(void)
 171 {
 172         reseteval();
 173         resetinput();
 174 }
 175
 176 /*
 177  * Read and execute commands.  "Top" is nonzero for the top level command
 178  * loop; it turns on prompting if the shell is interactive.
 179  */
 180
 181 static void
 182 cmdloop(int top)
 183 {
 184         union node *n;
 185         struct stackmark smark;
 186         int inter;
 187         int numeof = 0;
 188
 189         TRACE(("cmdloop(%d) called\n", top));
 190         setstackmark(&smark);
 191         for (;;) {
 192                 if (pendingsig)
 193                         dotrap();
 194                 inter = 0;
 195                 if (iflag && top) {
 196                         inter++;
 197                         showjobs(1, SHOWJOBS_DEFAULT);
 198                         chkmail(0);
 199                         flushout(&output);
 200                 }
 201                 n = parsecmd(inter);
 202                 /* showtree(n); DEBUG */
 203                 if (n == NEOF) {
 204                         if (!top || numeof >= 50)
 205                                 break;
 206                         if (!stoppedjobs()) {
 207                                 if (!Iflag)
 208                                         break;
 209                                 out2fmt_flush("\nUse \"exit\" to leave shell.\n");
 210                         }
 211                         numeof++;
 212                 } else if (n != NULL && nflag == 0) {
 213                         job_warning = (job_warning == 2) ? 1 : 0;
 214                         numeof = 0;
 215                         evaltree(n, 0);
 216                 }
 217                 popstackmark(&smark);
 218                 setstackmark(&smark);
 219                 if (evalskip != 0) {
 220                         if (evalskip == SKIPRETURN)
 221                                 evalskip = 0;
 222                         break;
 223                 }
 224         }
 225         popstackmark(&smark);
 226         if (top && iflag) {
 227                 out2c('\n');
 228                 flushout(out2);
 229         }
 230 }
 231
 232
 233
 234 /*
 235  * Read /etc/profile or .profile.  Return on error.
 236  */
 237
 238 static void
 239 read_profile(const char *name)
 240 {
 241         int fd;
 242         const char *expandedname;
 243
 244         expandedname = expandstr(name);
 245         if (expandedname == NULL)
 246                 return;
 247         INTOFF;
 248         if ((fd = open(expandedname, O_RDONLY | O_CLOEXEC_MAYBE)) >= 0)
 249                 setinputfd(fd, 1);
 250         INTON;
 251         if (fd < 0)
 252                 return;
 253         cmdloop(0);
 254         popfile();
 255 }
 256
 257
 258
 259 /*
 260  * Read a file containing shell functions.
 261  */
 262
 263 void
 264 readcmdfile(const char *name)
 265 {
 266         setinputfile(name, 1);
 267         cmdloop(0);
 268         popfile();
 269 }
 270
 271
 272
 273 /*
 274  * Take commands from a file.  To be compatible we should do a path
 275  * search for the file, which is necessary to find sub-commands.
 276  */
 277
 278
 279 static char *
 280 find_dot_file(char *basename)
 281 {
 282         char *fullname;
 283         const char *opt;
 284         const char *path = pathval();
 285         struct stat statb;
 286
 287         /* don't try this for absolute or relative paths */
 288         if( strchr(basename, '/'))
 289                 return basename;
 290
 291         while ((fullname = padvance(&path, &opt, basename)) != NULL) {
 292                 if ((stat(fullname, &statb) == 0) && S_ISREG(statb.st_mode)) {
 293                         /*
 294                          * Don't bother freeing here, since it will
 295                          * be freed by the caller.
 296                          */
 297                         return fullname;
 298                 }
 299                 stunalloc(fullname);
 300         }
 301         return basename;
 302 }
 303
 304 int
 305 dotcmd(int argc, char **argv)
 306 {
 307         char *filename, *fullname;
 308
 309         if (argc < 2)
 310                 error("missing filename");
 311
 312         exitstatus = 0;
 313
 314         /*
 315          * Because we have historically not supported any options,
 316          * only treat "--" specially.
 317          */
 318         filename = argc > 2 && strcmp(argv[1], "--") == 0 ? argv[2] : argv[1];
 319
 320         fullname = find_dot_file(filename);
 321         setinputfile(fullname, 1);
 322         commandname = fullname;
 323         cmdloop(0);
 324         popfile();
 325         return exitstatus;
 326 }
 327
 328
 329 int
 330 exitcmd(int argc, char **argv)
 331 {
 332         if (stoppedjobs())
 333                 return 0;
 334         if (argc > 1)
 335                 exitshell(number(argv[1]));
 336         else
 337                 exitshell_savedstatus();
 338 }