NetBSD-5.0.2/dist/nvi/ex/ex_filter.c
/* $NetBSD: ex_filter.c,v 1.1.1.2.6.1 2009/01/20 02:41:12 snj Exp $ */
/*-
* Copyright (c) 1991, 1993, 1994
* The Regents of the University of California. All rights reserved.
* Copyright (c) 1991, 1993, 1994, 1995, 1996
* Keith Bostic. All rights reserved.
*
* See the LICENSE file for redistribution information.
*/
#include "config.h"
#ifndef lint
static const char sccsid[] = "Id: ex_filter.c,v 10.44 2003/11/05 17:11:54 skimo Exp (Berkeley) Date: 2003/11/05 17:11:54";
#endif /* not lint */
#include <sys/types.h>
#include <sys/queue.h>
#include <bitstring.h>
#include <errno.h>
#include <fcntl.h>
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "../common/common.h"
static int filter_ldisplay __P((SCR *, FILE *));
static pid_t
runcmd(SCR *sp, const char *np, int* input, int *output)
{
pid_t pid;
const char *name;
switch (pid = vfork()) {
case -1: /* Error. */
msgq(sp, M_SYSERR, "vfork");
return -1;
case 0: /* Utility. */
/*
* Redirect stdin from the read end of the input pipe, and
* redirect stdout/stderr to the write end of the output pipe.
*
* !!!
* Historically, ex only directed stdout into the input pipe,
* letting stderr come out on the terminal as usual. Vi did
* not, directing both stdout and stderr into the input pipe.
* We match that practice in both ex and vi for consistency.
*/
if (input[0] != -1)
(void)dup2(input[0], STDIN_FILENO);
(void)dup2(output[1], STDOUT_FILENO);
(void)dup2(output[1], STDERR_FILENO);
/* Close the utility's file descriptors. */
if (input[0] != -1)
(void)close(input[0]);
if (input[1] != -1)
(void)close(input[1]);
(void)close(output[0]);
(void)close(output[1]);
if ((name = strrchr(O_STR(sp, O_SHELL), '/')) == NULL)
name = O_STR(sp, O_SHELL);
else
++name;
execl(O_STR(sp, O_SHELL), name, "-c", np, (char *)NULL);
msgq_str(sp, M_SYSERR, O_STR(sp, O_SHELL), "execl: %s");
_exit (127);
/* NOTREACHED */
default: /* Parent-reader, parent-writer. */
/* Close the pipe ends neither parent will use. */
if (input[0] != -1)
(void)close(input[0]);
(void)close(output[1]);
return pid;
}
}
/*
* ex_filter --
* Run a range of lines through a filter utility and optionally
* replace the original text with the stdout/stderr output of
* the utility.
*
* PUBLIC: int ex_filter __P((SCR *,
* PUBLIC: EXCMD *, MARK *, MARK *, MARK *, CHAR_T *, enum filtertype));
*/
int
ex_filter(SCR *sp, EXCMD *cmdp, MARK *fm, MARK *tm, MARK *rp, CHAR_T *cmd, enum filtertype ftype)
{
FILE *ifp, *ofp;
pid_t parent_writer_pid, utility_pid;
db_recno_t nread;
int input[2], output[2], rval;
const char *np;
size_t nlen;
rval = 0;
/* Set return cursor position, which is never less than line 1. */
*rp = *fm;
if (rp->lno == 0)
rp->lno = 1;
/* We're going to need a shell. */
if (opts_empty(sp, O_SHELL, 0))
return (1);
/*
* There are three different processes running through this code.
* They are the utility, the parent-writer and the parent-reader.
* The parent-writer is the process that writes from the file to
* the utility, the parent reader is the process that reads from
* the utility.
*
* Input and output are named from the utility's point of view.
* The utility reads from input[0] and the parent(s) write to
* input[1]. The parent(s) read from output[0] and the utility
* writes to output[1].
*
* !!!
* Historically, in the FILTER_READ case, the utility reads from
* the terminal (e.g. :r! cat works). Otherwise open up utility
* input pipe.
*/
ofp = NULL;
input[0] = input[1] = output[0] = output[1] = -1;
if (ftype != FILTER_READ && pipe(input) < 0) {
msgq(sp, M_SYSERR, "pipe");
goto err;
}
/* Open up utility output pipe. */
if (pipe(output) < 0) {
msgq(sp, M_SYSERR, "pipe");
goto err;
}
if ((ofp = fdopen(output[0], "r")) == NULL) {
msgq(sp, M_SYSERR, "fdopen");
goto err;
}
/* Fork off the utility process. */
INT2SYS(sp, cmd, STRLEN(cmd)+1, np, nlen);
utility_pid = runcmd(sp, np, input, output);
/*
* FILTER_RBANG, FILTER_READ:
*
* Reading is the simple case -- we don't need a parent writer,
* so the parent reads the output from the read end of the output
* pipe until it finishes, then waits for the child. Ex_readfp
* appends to the MARK, and closes ofp.
*
* For FILTER_RBANG, there is nothing to write to the utility.
* Make sure it doesn't wait forever by closing its standard
* input.
*
* !!!
* Set the return cursor to the last line read in for FILTER_READ.
* Historically, this behaves differently from ":r file" command,
* which leaves the cursor at the first line read in. Check to
* make sure that it's not past EOF because we were reading into an
* empty file.
*/
if (ftype == FILTER_RBANG || ftype == FILTER_READ) {
if (ftype == FILTER_RBANG)
(void)close(input[1]);
if (ex_readfp(sp, "filter", ofp, fm, &nread, 1))
rval = 1;
sp->rptlines[L_ADDED] += nread;
if (ftype == FILTER_READ) {
if (fm->lno == 0)
rp->lno = nread;
else
rp->lno += nread;
}
goto uwait;
}
/*
* FILTER_BANG, FILTER_WRITE
*
* Here we need both a reader and a writer. Temporary files are
* expensive and we'd like to avoid disk I/O. Using pipes has the
* obvious starvation conditions. It's done as follows:
*
* fork
* child
* write lines out
* exit
* parent
* FILTER_BANG:
* read lines into the file
* delete old lines
* FILTER_WRITE
* read and display lines
* wait for child
*
* XXX
* We get away without locking the underlying database because we know
* that none of the records that we're reading will be modified until
* after we've read them. This depends on the fact that the current
* B+tree implementation doesn't balance pages or similar things when
* it inserts new records. When the DB code has locking, we should
* treat vi as if it were multiple applications sharing a database, and
* do the required locking. If necessary a work-around would be to do
* explicit locking in the line.c:db_get() code, based on the flag set
* here.
*/
F_SET(sp->ep, F_MULTILOCK);
switch (parent_writer_pid = fork()) {
case -1: /* Error. */
msgq(sp, M_SYSERR, "fork");
(void)close(input[1]);
(void)close(output[0]);
rval = 1;
break;
case 0: /* Parent-writer. */
/*
* Write the selected lines to the write end of the input
* pipe. This instance of ifp is closed by ex_writefp.
*/
(void)close(output[0]);
if ((ifp = fdopen(input[1], "w")) == NULL)
_exit (1);
_exit(ex_writefp(sp, "filter", ifp, fm, tm, NULL, NULL, 1));
/* NOTREACHED */
default: /* Parent-reader. */
(void)close(input[1]);
if (ftype == FILTER_WRITE) {
/*
* Read the output from the read end of the output
* pipe and display it. Filter_ldisplay closes ofp.
*/
if (filter_ldisplay(sp, ofp))
rval = 1;
} else {
/*
* Read the output from the read end of the output
* pipe. Ex_readfp appends to the MARK and closes
* ofp.
*/
if (ex_readfp(sp, "filter", ofp, tm, &nread, 1))
rval = 1;
sp->rptlines[L_ADDED] += nread;
}
/* Wait for the parent-writer. */
if (proc_wait(sp,
(long)parent_writer_pid, "parent-writer", 0, 1))
rval = 1;
/* Delete any lines written to the utility. */
if (rval == 0 && ftype == FILTER_BANG &&
(cut(sp, NULL, fm, tm, CUT_LINEMODE) ||
del(sp, fm, tm, 1))) {
rval = 1;
break;
}
/*
* If the filter had no output, we may have just deleted
* the cursor. Don't do any real error correction, we'll
* try and recover later.
*/
if (rp->lno > 1 && !db_exist(sp, rp->lno))
--rp->lno;
break;
}
F_CLR(sp->ep, F_MULTILOCK);
/*
* !!!
* Ignore errors on vi file reads, to make reads prettier. It's
* completely inconsistent, and historic practice.
*/
uwait: INT2CHAR(sp, cmd, STRLEN(cmd) + 1, np, nlen);
return (proc_wait(sp, (long)utility_pid, np,
ftype == FILTER_READ && F_ISSET(sp, SC_VI) ? 1 : 0, 0) || rval);
err: if (input[0] != -1)
(void)close(input[0]);
if (input[1] != -1)
(void)close(input[1]);
if (ofp != NULL)
(void)fclose(ofp);
else if (output[0] != -1)
(void)close(output[0]);
if (output[1] != -1)
(void)close(output[1]);
return 1;
}
/*
* filter_ldisplay --
* Display output from a utility.
*
* !!!
* Historically, the characters were passed unmodified to the terminal.
* We use the ex print routines to make sure they're printable.
*/
static int
filter_ldisplay(SCR *sp, FILE *fp)
{
size_t len;
size_t wlen;
const CHAR_T *wp;
EX_PRIVATE *exp;
for (exp = EXP(sp); !ex_getline(sp, fp, &len) && !INTERRUPTED(sp);) {
FILE2INT5(sp, exp->ibcw, exp->ibp, len, wp, wlen);
if (ex_ldisplay(sp, wp, wlen, 0, 0))
break;
}
if (ferror(fp))
msgq(sp, M_SYSERR, "filter read");
(void)fclose(fp);
return (0);
}