minix/commands/ash/input.c

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2005-04-21 16:53:53 +02:00
/*-
* Copyright (c) 1991 The Regents of the University of California.
* 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. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. 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.
*/
#ifndef lint
static char sccsid[] = "@(#)input.c 5.4 (Berkeley) 7/1/91";
#endif /* not lint */
/*
* This file implements the input routines used by the parser.
*/
#include <sys/types.h>
#include <stdio.h> /* defines BUFSIZ */
#include "shell.h"
#include <fcntl.h>
#include <errno.h>
#include "syntax.h"
#include "input.h"
#include "output.h"
#include "memalloc.h"
#include "error.h"
#define EOF_NLEFT -99 /* value of parsenleft when EOF pushed back */
/*
* The parsefile structure pointed to by the global variable parsefile
* contains information about the current file being read.
*/
MKINIT
struct parsefile {
int linno; /* current line */
int fd; /* file descriptor (or -1 if string) */
int nleft; /* number of chars left in buffer */
char *nextc; /* next char in buffer */
struct parsefile *prev; /* preceding file on stack */
char *buf; /* input buffer */
};
int plinno = 1; /* input line number */
MKINIT int parsenleft; /* copy of parsefile->nleft */
char *parsenextc; /* copy of parsefile->nextc */
MKINIT struct parsefile basepf; /* top level input file */
char basebuf[BUFSIZ]; /* buffer for top level input file */
struct parsefile *parsefile = &basepf; /* current input file */
char *pushedstring; /* copy of parsenextc when text pushed back */
int pushednleft; /* copy of parsenleft when text pushed back */
#if READLINE
char *readline __P((const char *prompt));
char *r_use_prompt = NULL; /* the prompt to use with readline */
#endif
#ifdef __STDC__
STATIC void pushfile(void);
#else
STATIC void pushfile();
#endif
#ifdef mkinit
INCLUDE "input.h"
INCLUDE "error.h"
INIT {
extern char basebuf[];
basepf.nextc = basepf.buf = basebuf;
}
RESET {
if (exception != EXSHELLPROC)
parsenleft = 0; /* clear input buffer */
popallfiles();
}
SHELLPROC {
popallfiles();
}
#endif
/*
* Read a line from the script.
*/
char *
pfgets(line, len)
char *line;
{
register char *p = line;
int nleft = len;
int c;
while (--nleft > 0) {
c = pgetc_macro();
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() {
return pgetc_macro();
}
/*
* Refill the input buffer and return the next input character:
*
* 1) If a string was pushed back on the input, switch back to the regular
* buffer.
* 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) Call read to read in the characters.
* 4) Delete all nul characters from the buffer.
*/
int
preadbuffer() {
register char *p, *q;
register int i;
if (pushedstring) {
parsenextc = pushedstring;
pushedstring = NULL;
parsenleft = pushednleft;
if (--parsenleft >= 0)
return *parsenextc++;
}
if (parsenleft == EOF_NLEFT || parsefile->buf == NULL)
return PEOF;
flushout(&output);
flushout(&errout);
#if READLINE
/* Use the readline() call if a prompt is to be printed (interactive). */
if (r_use_prompt != NULL) {
char *prompt;
char *line;
p = parsenextc = parsefile->buf;
prompt = r_use_prompt;
r_use_prompt = NULL;
if ((line = readline(prompt)) == NULL) {
parsenleft = EOF_NLEFT;
return PEOF;
}
strcpy(p, line);
free(line);
i = strlen(p);
p[i++] = '\n';
} else {
#endif
retry:
p = parsenextc = parsefile->buf;
i = read(parsefile->fd, p, BUFSIZ);
if (i <= 0) {
if (i < 0) {
if (errno == EINTR)
goto retry;
#ifdef EWOULDBLOCK
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;
}
}
}
#endif
}
parsenleft = EOF_NLEFT;
return PEOF;
}
#if READLINE
}
#endif
parsenleft = i - 1;
/* delete nul characters */
for (;;) {
if (*p++ == '\0')
break;
if (--i <= 0)
return *parsenextc++; /* no nul characters */
}
q = p - 1;
while (--i > 0) {
if (*p != '\0')
*q++ = *p;
p++;
}
if (q == parsefile->buf)
goto retry; /* buffer contained nothing but nuls */
parsenleft = q - parsefile->buf - 1;
return *parsenextc++;
}
/*
* Undo the last call to pgetc. Only one character may be pushed back.
* PEOF may be pushed back.
*/
void
pungetc() {
parsenleft++;
parsenextc--;
}
/*
* Push a string back onto the input. This code doesn't work if the user
* tries to push back more than one string at once.
*/
void
ppushback(string, length)
char *string;
{
pushedstring = parsenextc;
pushednleft = parsenleft;
parsenextc = string;
parsenleft = length;
}
/*
* Set the input to take input from a file. If push is set, push the
* old input onto the stack first.
*/
void
setinputfile(fname, push)
char *fname;
{
int fd;
int fd2;
INTOFF;
if ((fd = open(fname, O_RDONLY)) < 0)
error("Can't open %s", fname);
if (fd < 10) {
fd2 = copyfd(fd, 10);
close(fd);
if (fd2 < 0)
error("Out of file descriptors");
fd = fd2;
}
setinputfd(fd, push);
INTON;
}
/*
* Like setinputfile, but takes an open file descriptor. Call this with
* interrupts off.
*/
void
setinputfd(fd, push) {
(void) fcntl(fd, F_SETFD, fcntl(fd, F_GETFD) | FD_CLOEXEC);
if (push) {
pushfile();
parsefile->buf = ckmalloc(BUFSIZ);
}
if (parsefile->fd > 0)
close(parsefile->fd);
parsefile->fd = fd;
if (parsefile->buf == NULL)
parsefile->buf = ckmalloc(BUFSIZ);
parsenleft = 0;
plinno = 1;
}
/*
* Like setinputfile, but takes input from a string.
*/
void
setinputstring(string, push)
char *string;
{
INTOFF;
if (push)
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() {
struct parsefile *pf;
parsefile->nleft = parsenleft;
parsefile->nextc = parsenextc;
parsefile->linno = plinno;
pf = (struct parsefile *)ckmalloc(sizeof (struct parsefile));
pf->prev = parsefile;
pf->fd = -1;
parsefile = pf;
}
void
popfile() {
struct parsefile *pf = parsefile;
INTOFF;
if (pf->fd >= 0)
close(pf->fd);
if (pf->buf)
ckfree(pf->buf);
parsefile = pf->prev;
ckfree(pf);
parsenleft = parsefile->nleft;
parsenextc = parsefile->nextc;
plinno = parsefile->linno;
INTON;
}
/*
* Return to top level.
*/
void
popallfiles() {
while (parsefile != &basepf)
popfile();
}
/*
* Close the file(s) that the shell is reading commands from. Called
* after a fork is done.
*/
void
closescript() {
popallfiles();
if (parsefile->fd > 0) {
close(parsefile->fd);
parsefile->fd = 0;
}
}