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main.c

/*-
 * Copyright (c) 1991, 1993
 *    The Regents of the University of California.  All rights reserved.
 * Copyright (c) 1997-2005
 *    Herbert Xu <herbert@gondor.apana.org.au>.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Kenneth Almquist.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <stdio.h>
#include <signal.h>
#include <sys/stat.h>
#include <unistd.h>
#include <fcntl.h>


#include "shell.h"
#include "main.h"
#include "mail.h"
#include "options.h"
#include "output.h"
#include "parser.h"
#include "nodes.h"
#include "expand.h"
#include "eval.h"
#include "jobs.h"
#include "input.h"
#include "trap.h"
#include "var.h"
#include "show.h"
#include "memalloc.h"
#include "error.h"
#include "init.h"
#include "mystring.h"
#include "exec.h"
#include "cd.h"

#ifdef HETIO
#include "hetio.h"
#endif

#define PROFILE 0

int rootpid;
int shlvl;
#ifdef __GLIBC__
int *dash_errno;
#endif
#if PROFILE
short profile_buf[16384];
extern int etext();
#endif

STATIC void read_profile(const char *);
STATIC char *find_dot_file(char *);
static int cmdloop(int);
int main(int, char **);

/*
 * Main routine.  We initialize things, parse the arguments, execute
 * profiles if we're a login shell, and then call cmdloop to execute
 * commands.  The setjmp call sets up the location to jump to when an
 * exception occurs.  When an exception occurs the variable "state"
 * is used to figure out how far we had gotten.
 */

int
main(int argc, char **argv)
{
      char *shinit;
      volatile int state;
      struct jmploc jmploc;
      struct stackmark smark;

#ifdef __GLIBC__
      dash_errno = __errno_location();
#endif

#if PROFILE
      monitor(4, etext, profile_buf, sizeof profile_buf, 50);
#endif
      state = 0;
      if (unlikely(setjmp(jmploc.loc))) {
            int e;
            int s;

            reset();

            e = exception;
            if (e == EXERROR)
                  exitstatus = 2;

            s = state;
            if (e == EXEXIT || s == 0 || iflag == 0 || shlvl)
                  exitshell();

            if (e == EXINT
#if ATTY
             && (! attyset() || equal(termval(), "emacs"))
#endif
             ) {
                  out2c('\n');
#ifdef FLUSHERR
                  flushout(out2);
#endif
            }
            popstackmark(&smark);
            FORCEINTON;                   /* enable interrupts */
            if (s == 1)
                  goto state1;
            else if (s == 2)
                  goto state2;
            else if (s == 3)
                  goto state3;
            else
                  goto state4;
      }
      handler = &jmploc;
#ifdef DEBUG
      opentrace();
      trputs("Shell args:  ");  trargs(argv);
#endif
      rootpid = getpid();
      init();
      setstackmark(&smark);
      procargs(argc, argv);
      if (argv[0] && argv[0][0] == '-') {
            state = 1;
            read_profile("/etc/profile");
state1:
            state = 2;
            read_profile(".profile");
      }
state2:
      state = 3;
      if (
#ifndef linux
            getuid() == geteuid() && getgid() == getegid() &&
#endif
            iflag
      ) {
            if ((shinit = lookupvar("ENV")) != NULL && *shinit != '\0') {
                  read_profile(shinit);
            }
      }
state3:
      state = 4;
      if (minusc)
            evalstring(minusc, 0);

      if (sflag || minusc == NULL) {
state4:     /* XXX ??? - why isn't this before the "if" statement */
            cmdloop(1);
      }
#if PROFILE
      monitor(0);
#endif
#if GPROF
      {
            extern void _mcleanup(void);
            _mcleanup();
      }
#endif
      exitshell();
      /* NOTREACHED */
}


/*
 * Read and execute commands.  "Top" is nonzero for the top level command
 * loop; it turns on prompting if the shell is interactive.
 */

static int
cmdloop(int top)
{
      union node *n;
      struct stackmark smark;
      int inter;
      int numeof = 0;

      TRACE(("cmdloop(%d) called\n", top));
#ifdef HETIO
      if(iflag && top)
            hetio_init();
#endif
      for (;;) {
            int skip;

            setstackmark(&smark);
            if (jobctl)
                  showjobs(out2, SHOW_CHANGED);
            inter = 0;
            if (iflag && top) {
                  inter++;
                  chkmail();
            }
            n = parsecmd(inter);
            /* showtree(n); DEBUG */
            if (n == NEOF) {
                  if (!top || numeof >= 50)
                        break;
                  if (!stoppedjobs()) {
                        if (!Iflag)
                              break;
                        out2str("\nUse \"exit\" to leave shell.\n");
                  }
                  numeof++;
            } else if (nflag == 0) {
                  job_warning = (job_warning == 2) ? 1 : 0;
                  numeof = 0;
                  evaltree(n, 0);
            }
            popstackmark(&smark);

            skip = evalskip;
            if (skip) {
                  evalskip = 0;
                  return skip & SKIPEVAL;
            }
      }

      return 0;
}



/*
 * Read /etc/profile or .profile.  Return on error.
 */

STATIC void
read_profile(const char *name)
{
      int skip;

      if (setinputfile(name, INPUT_PUSH_FILE | INPUT_NOFILE_OK) < 0)
            return;

      skip = cmdloop(0);
      popfile();

      if (skip)
            exitshell();
}



/*
 * Read a file containing shell functions.
 */

void
readcmdfile(char *name)
{
      setinputfile(name, INPUT_PUSH_FILE);
      cmdloop(0);
      popfile();
}



/*
 * Take commands from a file.  To be compatible we should do a path
 * search for the file, which is necessary to find sub-commands.
 */


STATIC char *
find_dot_file(char *basename)
{
      char *fullname;
      const char *path = pathval();
      struct stat statb;

      /* don't try this for absolute or relative paths */
      if (strchr(basename, '/'))
            return basename;

      while ((fullname = padvance(&path, basename)) != NULL) {
            if ((stat(fullname, &statb) == 0) && S_ISREG(statb.st_mode)) {
                  /*
                   * Don't bother freeing here, since it will
                   * be freed by the caller.
                   */
                  return fullname;
            }
            stunalloc(fullname);
      }

      /* not found in the PATH */
      sh_error("%s: not found", basename);
      /* NOTREACHED */
}

int
dotcmd(int argc, char **argv)
{
      int status = 0;

      if (argc >= 2) {        /* That's what SVR2 does */
            char *fullname;

            fullname = find_dot_file(argv[1]);
            setinputfile(fullname, INPUT_PUSH_FILE);
            commandname = fullname;
            cmdloop(0);
            popfile();
            status = exitstatus;
      }
      return status;
}


int
exitcmd(int argc, char **argv)
{
      if (stoppedjobs())
            return 0;
      if (argc > 1)
            exitstatus = number(argv[1]);
      exraise(EXEXIT);
      /* NOTREACHED */
}

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