2 * Copyright (c) 1991, 1993, 1994
3 * The Regents of the University of California. All rights reserved.
4 * Copyright (c) 1991, 1993, 1994, 1995, 1996
5 * Keith Bostic. All rights reserved.
7 * See the LICENSE file for redistribution information.
13 static const char sccsid
[] = "$Id: ex_filter.c,v 10.42 2001/06/17 14:16:50 skimo Exp $ (Berkeley) $Date: 2001/06/17 14:16:50 $";
16 #include <sys/types.h>
17 #include <sys/queue.h>
19 #include <bitstring.h>
28 #include "../common/common.h"
30 static int filter_ldisplay
__P((SCR
*, FILE *));
34 * Run a range of lines through a filter utility and optionally
35 * replace the original text with the stdout/stderr output of
38 * PUBLIC: int ex_filter __P((SCR *,
39 * PUBLIC: EXCMD *, MARK *, MARK *, MARK *, CHAR_T *, enum filtertype));
42 ex_filter(sp
, cmdp
, fm
, tm
, rp
, cmd
, ftype
)
47 enum filtertype ftype
;
50 pid_t parent_writer_pid
, utility_pid
;
52 int input
[2], output
[2], rval
;
59 /* Set return cursor position, which is never less than line 1. */
64 /* We're going to need a shell. */
65 if (opts_empty(sp
, O_SHELL
, 0))
69 * There are three different processes running through this code.
70 * They are the utility, the parent-writer and the parent-reader.
71 * The parent-writer is the process that writes from the file to
72 * the utility, the parent reader is the process that reads from
75 * Input and output are named from the utility's point of view.
76 * The utility reads from input[0] and the parent(s) write to
77 * input[1]. The parent(s) read from output[0] and the utility
78 * writes to output[1].
81 * Historically, in the FILTER_READ case, the utility reads from
82 * the terminal (e.g. :r! cat works). Otherwise open up utility
86 input
[0] = input
[1] = output
[0] = output
[1] = -1;
87 if (ftype
!= FILTER_READ
&& pipe(input
) < 0) {
88 msgq(sp
, M_SYSERR
, "pipe");
92 /* Open up utility output pipe. */
93 if (pipe(output
) < 0) {
94 msgq(sp
, M_SYSERR
, "pipe");
97 if ((ofp
= fdopen(output
[0], "r")) == NULL
) {
98 msgq(sp
, M_SYSERR
, "fdopen");
102 /* Fork off the utility process. */
103 switch (utility_pid
= vfork()) {
104 case -1: /* Error. */
105 msgq(sp
, M_SYSERR
, "vfork");
106 err
: if (input
[0] != -1)
107 (void)close(input
[0]);
109 (void)close(input
[1]);
112 else if (output
[0] != -1)
113 (void)close(output
[0]);
115 (void)close(output
[1]);
117 case 0: /* Utility. */
119 * Redirect stdin from the read end of the input pipe, and
120 * redirect stdout/stderr to the write end of the output pipe.
123 * Historically, ex only directed stdout into the input pipe,
124 * letting stderr come out on the terminal as usual. Vi did
125 * not, directing both stdout and stderr into the input pipe.
126 * We match that practice in both ex and vi for consistency.
129 (void)dup2(input
[0], STDIN_FILENO
);
130 (void)dup2(output
[1], STDOUT_FILENO
);
131 (void)dup2(output
[1], STDERR_FILENO
);
133 /* Close the utility's file descriptors. */
135 (void)close(input
[0]);
137 (void)close(input
[1]);
138 (void)close(output
[0]);
139 (void)close(output
[1]);
141 if ((name
= strrchr(O_STR(sp
, O_SHELL
), '/')) == NULL
)
142 name
= O_STR(sp
, O_SHELL
);
146 INT2SYS(sp
, cmd
, STRLEN(cmd
)+1, np
, nlen
);
147 execl(O_STR(sp
, O_SHELL
), name
, "-c", np
, NULL
);
148 msgq_str(sp
, M_SYSERR
, O_STR(sp
, O_SHELL
), "execl: %s");
151 default: /* Parent-reader, parent-writer. */
152 /* Close the pipe ends neither parent will use. */
154 (void)close(input
[0]);
155 (void)close(output
[1]);
160 * FILTER_RBANG, FILTER_READ:
162 * Reading is the simple case -- we don't need a parent writer,
163 * so the parent reads the output from the read end of the output
164 * pipe until it finishes, then waits for the child. Ex_readfp
165 * appends to the MARK, and closes ofp.
167 * For FILTER_RBANG, there is nothing to write to the utility.
168 * Make sure it doesn't wait forever by closing its standard
172 * Set the return cursor to the last line read in for FILTER_READ.
173 * Historically, this behaves differently from ":r file" command,
174 * which leaves the cursor at the first line read in. Check to
175 * make sure that it's not past EOF because we were reading into an
178 if (ftype
== FILTER_RBANG
|| ftype
== FILTER_READ
) {
179 if (ftype
== FILTER_RBANG
)
180 (void)close(input
[1]);
182 if (ex_readfp(sp
, "filter", ofp
, fm
, &nread
, 1))
184 sp
->rptlines
[L_ADDED
] += nread
;
185 if (ftype
== FILTER_READ
)
194 * FILTER_BANG, FILTER_WRITE
196 * Here we need both a reader and a writer. Temporary files are
197 * expensive and we'd like to avoid disk I/O. Using pipes has the
198 * obvious starvation conditions. It's done as follows:
206 * read lines into the file
209 * read and display lines
213 * We get away without locking the underlying database because we know
214 * that none of the records that we're reading will be modified until
215 * after we've read them. This depends on the fact that the current
216 * B+tree implementation doesn't balance pages or similar things when
217 * it inserts new records. When the DB code has locking, we should
218 * treat vi as if it were multiple applications sharing a database, and
219 * do the required locking. If necessary a work-around would be to do
220 * explicit locking in the line.c:db_get() code, based on the flag set
223 F_SET(sp
->ep
, F_MULTILOCK
);
224 switch (parent_writer_pid
= fork()) {
225 case -1: /* Error. */
226 msgq(sp
, M_SYSERR
, "fork");
227 (void)close(input
[1]);
228 (void)close(output
[0]);
231 case 0: /* Parent-writer. */
233 * Write the selected lines to the write end of the input
234 * pipe. This instance of ifp is closed by ex_writefp.
236 (void)close(output
[0]);
237 if ((ifp
= fdopen(input
[1], "w")) == NULL
)
239 _exit(ex_writefp(sp
, "filter", ifp
, fm
, tm
, NULL
, NULL
, 1));
242 default: /* Parent-reader. */
243 (void)close(input
[1]);
244 if (ftype
== FILTER_WRITE
) {
246 * Read the output from the read end of the output
247 * pipe and display it. Filter_ldisplay closes ofp.
249 if (filter_ldisplay(sp
, ofp
))
253 * Read the output from the read end of the output
254 * pipe. Ex_readfp appends to the MARK and closes
257 if (ex_readfp(sp
, "filter", ofp
, tm
, &nread
, 1))
259 sp
->rptlines
[L_ADDED
] += nread
;
262 /* Wait for the parent-writer. */
264 (long)parent_writer_pid
, "parent-writer", 0, 1))
267 /* Delete any lines written to the utility. */
268 if (rval
== 0 && ftype
== FILTER_BANG
&&
269 (cut(sp
, NULL
, fm
, tm
, CUT_LINEMODE
) ||
270 del(sp
, fm
, tm
, 1))) {
276 * If the filter had no output, we may have just deleted
277 * the cursor. Don't do any real error correction, we'll
278 * try and recover later.
280 if (rp
->lno
> 1 && !db_exist(sp
, rp
->lno
))
284 F_CLR(sp
->ep
, F_MULTILOCK
);
288 * Ignore errors on vi file reads, to make reads prettier. It's
289 * completely inconsistent, and historic practice.
291 uwait
: INT2CHAR(sp
, cmd
, STRLEN(cmd
) + 1, np
, nlen
);
292 return (proc_wait(sp
, (long)utility_pid
, np
,
293 ftype
== FILTER_READ
&& F_ISSET(sp
, SC_VI
) ? 1 : 0, 0) || rval
);
298 * Display output from a utility.
301 * Historically, the characters were passed unmodified to the terminal.
302 * We use the ex print routines to make sure they're printable.
305 filter_ldisplay(sp
, fp
)
313 for (exp
= EXP(sp
); !ex_getline(sp
, fp
, &len
) && !INTERRUPTED(sp
);) {
314 if (ex_ldisplay(sp
, exp
->ibp
, len
, 0, 0))
318 msgq(sp
, M_SYSERR
, "filter read");