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input.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>      /* defines BUFSIZ */
#include <fcntl.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>

/*
 * This file implements the input routines used by the parser.
 */

#include "shell.h"
#include "redir.h"
#include "syntax.h"
#include "input.h"
#include "output.h"
#include "options.h"
#include "memalloc.h"
#include "error.h"
#include "alias.h"
#include "parser.h"
#include "main.h"
#ifndef SMALL
#include "myhistedit.h"
#endif

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

#define EOF_NLEFT -99         /* value of parsenleft when EOF pushed back */
#define IBUFSIZ (BUFSIZ + 1)

MKINIT
struct strpush {
      struct strpush *prev;   /* preceding string on stack */
      char *prevstring;
      int prevnleft;
      struct alias *ap; /* if push was associated with an alias */
      char *string;           /* remember the string since it may change */
};

/*
 * The parsefile structure pointed to by the global variable parsefile
 * contains information about the current file being read.
 */

MKINIT
struct parsefile {
      struct parsefile *prev; /* preceding file on stack */
      int linno;        /* current line */
      int fd;                 /* file descriptor (or -1 if string) */
      int nleft;        /* number of chars left in this line */
      int lleft;        /* number of chars left in this buffer */
      char *nextc;            /* next char in buffer */
      char *buf;        /* input buffer */
      struct strpush *strpush; /* for pushing strings at this level */
      struct strpush basestrpush; /* so pushing one is fast */
};


int plinno = 1;               /* input line number */
int parsenleft;               /* copy of parsefile->nleft */
MKINIT int parselleft;        /* copy of parsefile->lleft */
char *parsenextc;       /* copy of parsefile->nextc */
MKINIT struct parsefile basepf;     /* top level input file */
MKINIT char basebuf[IBUFSIZ]; /* buffer for top level input file */
struct parsefile *parsefile = &basepf;    /* current input file */
int whichprompt;        /* 1 == PS1, 2 == PS2 */

#ifndef SMALL
EditLine *el;                 /* cookie for editline package */
#endif

STATIC void pushfile(void);
static int preadfd(void);

#ifdef mkinit
INCLUDE <stdio.h>
INCLUDE "input.h"
INCLUDE "error.h"

INIT {
      basepf.nextc = basepf.buf = basebuf;
}

RESET {
      parselleft = parsenleft = 0;  /* clear input buffer */
      popallfiles();
}
#endif


/*
 * Read a line from the script.
 */

char *
pfgets(char *line, int len)
{
      char *p = line;
      int nleft = len;
      int c;

      while (--nleft > 0) {
            c = pgetc2();
            if (c == PEOF) {
                  if (p == line)
                        return NULL;
                  break;
            }
            *p++ = c;
            if (c == '\n')
                  break;
      }
      *p = '\0';
      return line;
}


/*
 * Read a character from the script, returning PEOF on end of file.
 * Nul characters in the input are silently discarded.
 */

int
pgetc(void)
{
      return pgetc_macro();
}


/*
 * Same as pgetc(), but ignores PEOA.
 */

int
pgetc2()
{
      int c;
      do {
            c = pgetc_macro();
      } while (c == PEOA);
      return c;
}


static int
preadfd(void)
{
      int nr;
      char *buf =  parsefile->buf;
      parsenextc = buf;

retry:
#ifndef SMALL
      if (parsefile->fd == 0 && el) {
            static const char *rl_cp;
            static int el_len;

            if (rl_cp == NULL)
                  rl_cp = el_gets(el, &el_len);
            if (rl_cp == NULL)
                  nr = 0;
            else {
                  nr = el_len;
                  if (nr > IBUFSIZ - 1)
                        nr = IBUFSIZ - 1;
                  memcpy(buf, rl_cp, nr);
                  if (nr != el_len) {
                        el_len -= nr;
                        rl_cp += nr;
                  } else
                        rl_cp = 0;
            }

      } else
#endif

#ifdef HETIO
            nr = hetio_read_input(parsefile->fd);
            if (nr == -255)
#endif
            nr = read(parsefile->fd, buf, IBUFSIZ - 1);


      if (nr < 0) {
            if (errno == EINTR)
                  goto retry;
            if (parsefile->fd == 0 && errno == EWOULDBLOCK) {
                  int flags = fcntl(0, F_GETFL, 0);
                  if (flags >= 0 && flags & O_NONBLOCK) {
                        flags &=~ O_NONBLOCK;
                        if (fcntl(0, F_SETFL, flags) >= 0) {
                              out2str("sh: turning off NDELAY mode\n");
                              goto retry;
                        }
                  }
            }
      }
      return nr;
}

/*
 * Refill the input buffer and return the next input character:
 *
 * 1) If a string was pushed back on the input, pop it;
 * 2) If an EOF was pushed back (parsenleft == EOF_NLEFT) or we are reading
 *    from a string so we can't refill the buffer, return EOF.
 * 3) If the is more stuff in this buffer, use it else call read to fill it.
 * 4) Process input up to the next newline, deleting nul characters.
 */

int
preadbuffer(void)
{
      char *q;
      int more;
#ifndef SMALL
      int something;
#endif
      char savec;

      while (unlikely(parsefile->strpush)) {
            if (
                  parsenleft == -1 && parsefile->strpush->ap &&
                  parsenextc[-1] != ' ' && parsenextc[-1] != '\t'
            ) {
                  return PEOA;
            }
            popstring();
            if (--parsenleft >= 0)
                  return (*parsenextc++);
      }
      if (unlikely(parsenleft == EOF_NLEFT || parsefile->buf == NULL))
            return PEOF;
      flushout(&output);
#ifdef FLUSHERR
      flushout(&errout);
#endif

      more = parselleft;
      if (more <= 0) {
again:
            if ((more = preadfd()) <= 0) {
                  parselleft = parsenleft = EOF_NLEFT;
                  return PEOF;
            }
      }

      q = parsenextc;

      /* delete nul characters */
#ifndef SMALL
      something = 0;
#endif
      for (;;) {
            int c;

            more--;
            c = *q;

            if (!c)
                  memmove(q, q + 1, more);
            else {
                  q++;

                  if (c == '\n') {
                        parsenleft = q - parsenextc - 1;
                        break;
                  }

#ifndef SMALL
                  switch (c) {
                  default:
                        something = 1;
                        /* fall through */
                  case '\t':
                  case ' ':
                        break;
                  }
#endif
            }

            if (more <= 0) {
                  parsenleft = q - parsenextc - 1;
                  if (parsenleft < 0)
                        goto again;
                  break;
            }
      }
      parselleft = more;

      savec = *q;
      *q = '\0';

#ifndef SMALL
      if (parsefile->fd == 0 && hist && something) {
            HistEvent he;
            INTOFF;
            history(hist, &he, whichprompt == 1? H_ENTER : H_APPEND,
                parsenextc);
            INTON;
      }
#endif

      if (vflag) {
            out2str(parsenextc);
#ifdef FLUSHERR
            flushout(out2);
#endif
      }

      *q = savec;

      return *parsenextc++;
}

/*
 * Undo the last call to pgetc.  Only one character may be pushed back.
 * PEOF may be pushed back.
 */

void
pungetc(void)
{
      parsenleft++;
      parsenextc--;
}

/*
 * Push a string back onto the input at this current parsefile level.
 * We handle aliases this way.
 */
void
pushstring(char *s, void *ap)
{
      struct strpush *sp;
      size_t len;

      len = strlen(s);
      INTOFF;
/*dprintf("*** calling pushstring: %s, %d\n", s, len);*/
      if (parsefile->strpush) {
            sp = ckmalloc(sizeof (struct strpush));
            sp->prev = parsefile->strpush;
            parsefile->strpush = sp;
      } else
            sp = parsefile->strpush = &(parsefile->basestrpush);
      sp->prevstring = parsenextc;
      sp->prevnleft = parsenleft;
      sp->ap = (struct alias *)ap;
      if (ap) {
            ((struct alias *)ap)->flag |= ALIASINUSE;
            sp->string = s;
      }
      parsenextc = s;
      parsenleft = len;
      INTON;
}

void
popstring(void)
{
      struct strpush *sp = parsefile->strpush;

      INTOFF;
      if (sp->ap) {
            if (parsenextc[-1] == ' ' || parsenextc[-1] == '\t') {
                  checkkwd |= CHKALIAS;
            }
            if (sp->string != sp->ap->val) {
                  ckfree(sp->string);
            }
            sp->ap->flag &= ~ALIASINUSE;
            if (sp->ap->flag & ALIASDEAD) {
                  unalias(sp->ap->name);
            }
      }
      parsenextc = sp->prevstring;
      parsenleft = sp->prevnleft;
/*dprintf("*** calling popstring: restoring to '%s'\n", parsenextc);*/
      parsefile->strpush = sp->prev;
      if (sp != &(parsefile->basestrpush))
            ckfree(sp);
      INTON;
}

/*
 * Set the input to take input from a file.  If push is set, push the
 * old input onto the stack first.
 */

int
setinputfile(const char *fname, int flags)
{
      int fd;
      int fd2;

      INTOFF;
      if ((fd = open(fname, O_RDONLY)) < 0) {
            if (flags & INPUT_NOFILE_OK)
                  goto out;
            sh_error("Can't open %s", fname);
      }
      if (fd < 10) {
            fd2 = copyfd(fd, 10);
            close(fd);
            if (fd2 < 0)
                  sh_error("Out of file descriptors");
            fd = fd2;
      }
      setinputfd(fd, flags & INPUT_PUSH_FILE);
out:
      INTON;
      return fd;
}


/*
 * Like setinputfile, but takes an open file descriptor.  Call this with
 * interrupts off.
 */

void
setinputfd(int fd, int push)
{
      (void) fcntl(fd, F_SETFD, FD_CLOEXEC);
      if (push) {
            pushfile();
            parsefile->buf = 0;
      }
      parsefile->fd = fd;
      if (parsefile->buf == NULL)
            parsefile->buf = ckmalloc(IBUFSIZ);
      parselleft = parsenleft = 0;
      plinno = 1;
}


/*
 * Like setinputfile, but takes input from a string.
 */

void
setinputstring(char *string)
{
      INTOFF;
      pushfile();
      parsenextc = string;
      parsenleft = strlen(string);
      parsefile->buf = NULL;
      plinno = 1;
      INTON;
}



/*
 * To handle the "." command, a stack of input files is used.  Pushfile
 * adds a new entry to the stack and popfile restores the previous level.
 */

STATIC void
pushfile(void)
{
      struct parsefile *pf;

      parsefile->nleft = parsenleft;
      parsefile->lleft = parselleft;
      parsefile->nextc = parsenextc;
      parsefile->linno = plinno;
      pf = (struct parsefile *)ckmalloc(sizeof (struct parsefile));
      pf->prev = parsefile;
      pf->fd = -1;
      pf->strpush = NULL;
      pf->basestrpush.prev = NULL;
      parsefile = pf;
}


void
popfile(void)
{
      struct parsefile *pf = parsefile;

      INTOFF;
      if (pf->fd >= 0)
            close(pf->fd);
      if (pf->buf)
            ckfree(pf->buf);
      while (pf->strpush)
            popstring();
      parsefile = pf->prev;
      ckfree(pf);
      parsenleft = parsefile->nleft;
      parselleft = parsefile->lleft;
      parsenextc = parsefile->nextc;
      plinno = parsefile->linno;
      INTON;
}


/*
 * Return to top level.
 */

void
popallfiles(void)
{
      while (parsefile != &basepf)
            popfile();
}



/*
 * Close the file(s) that the shell is reading commands from.  Called
 * after a fork is done.
 */

void
closescript(void)
{
      popallfiles();
      if (parsefile->fd > 0) {
            close(parsefile->fd);
            parsefile->fd = 0;
      }
}

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