* Copyright (c) 1991 The Regents of the University of California.
* This code is derived from software contributed to Berkeley by
* %sccs.include.redist.c%
static char sccsid
[] = "@(#)input.c 5.1 (Berkeley) %G%";
* This file implements the input routines used by the parser.
#include <stdio.h> /* defines BUFSIZ */
#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.
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 */
STATIC
void pushfile(void);
basepf
.nextc
= basepf
.buf
= basebuf
;
if (exception
!= EXSHELLPROC
)
parsenleft
= 0; /* clear input buffer */
* Read a line from the script.
* Read a character from the script, returning PEOF on end of file.
* Nul characters in the input are silently discarded.
* 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
* 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.
parsenextc
= pushedstring
;
parsenleft
= pushednleft
;
if (parsenleft
== EOF_NLEFT
|| parsefile
->buf
== NULL
)
p
= parsenextc
= parsefile
->buf
;
i
= read(parsefile
->fd
, p
, BUFSIZ
);
if (i
< 0 && errno
== EINTR
)
/* delete nul characters */
return *parsenextc
++; /* no nul characters */
goto retry
; /* buffer contained nothing but nuls */
parsenleft
= q
- parsefile
->buf
- 1;
* Undo the last call to pgetc. Only one character may be pushed back.
* PEOF may be pushed back.
* 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.
ppushback(string
, length
)
pushedstring
= parsenextc
;
pushednleft
= parsenleft
;
* Set the input to take input from a file. If push is set, push the
* old input onto the stack first.
setinputfile(fname
, push
)
if ((fd
= open(fname
, O_RDONLY
)) < 0)
error("Can't open %s", fname
);
error("Out of file descriptors");
* Like setinputfile, but takes an open file descriptor. Call this with
parsefile
->buf
= ckmalloc(BUFSIZ
);
if (parsefile
->buf
== NULL
)
parsefile
->buf
= ckmalloc(BUFSIZ
);
* Like setinputfile, but takes input from a string.
setinputstring(string
, push
)
parsenleft
= strlen(string
);
* 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.
parsefile
->nleft
= parsenleft
;
parsefile
->nextc
= parsenextc
;
parsefile
->linno
= plinno
;
pf
= (struct parsefile
*)ckmalloc(sizeof (struct parsefile
));
struct parsefile
*pf
= parsefile
;
parsenleft
= parsefile
->nleft
;
parsenextc
= parsefile
->nextc
;
plinno
= parsefile
->linno
;
while (parsefile
!= &basepf
)
* Close the file(s) that the shell is reading commands from. Called