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.
12 #include <sys/types.h>
13 #include <sys/queue.h>
16 #include <bitstring.h>
25 #include "../common/common.h"
27 static int filter_ldisplay(SCR *, FILE *);
31 * Run a range of lines through a filter utility and optionally
32 * replace the original text with the stdout/stderr output of
35 * PUBLIC: int ex_filter(SCR *,
36 * PUBLIC: EXCMD *, MARK *, MARK *, MARK *, CHAR_T *, enum filtertype);
39 ex_filter(SCR *sp, EXCMD *cmdp, MARK *fm, MARK *tm, MARK *rp, CHAR_T *cmd, enum filtertype ftype)
42 pid_t parent_writer_pid, utility_pid;
44 int input[2], output[2], rval;
51 /* Set return cursor position, which is never less than line 1. */
56 /* We're going to need a shell. */
57 if (opts_empty(sp, O_SHELL, 0))
61 * There are three different processes running through this code.
62 * They are the utility, the parent-writer and the parent-reader.
63 * The parent-writer is the process that writes from the file to
64 * the utility, the parent reader is the process that reads from
67 * Input and output are named from the utility's point of view.
68 * The utility reads from input[0] and the parent(s) write to
69 * input[1]. The parent(s) read from output[0] and the utility
70 * writes to output[1].
73 * Historically, in the FILTER_READ case, the utility reads from
74 * the terminal (e.g. :r! cat works). Otherwise open up utility
78 input[0] = input[1] = output[0] = output[1] = -1;
79 if (ftype != FILTER_READ && pipe(input) < 0) {
80 msgq(sp, M_SYSERR, "pipe");
84 /* Open up utility output pipe. */
85 if (pipe(output) < 0) {
86 msgq(sp, M_SYSERR, "pipe");
89 if ((ofp = fdopen(output[0], "r")) == NULL) {
90 msgq(sp, M_SYSERR, "fdopen");
94 /* Fork off the utility process. */
95 switch (utility_pid = vfork()) {
97 msgq(sp, M_SYSERR, "vfork");
98 err: if (input[0] != -1)
99 (void)close(input[0]);
101 (void)close(input[1]);
104 else if (output[0] != -1)
105 (void)close(output[0]);
107 (void)close(output[1]);
109 case 0: /* Utility. */
111 * Redirect stdin from the read end of the input pipe, and
112 * redirect stdout/stderr to the write end of the output pipe.
115 * Historically, ex only directed stdout into the input pipe,
116 * letting stderr come out on the terminal as usual. Vi did
117 * not, directing both stdout and stderr into the input pipe.
118 * We match that practice in both ex and vi for consistency.
121 (void)dup2(input[0], STDIN_FILENO);
122 (void)dup2(output[1], STDOUT_FILENO);
123 (void)dup2(output[1], STDERR_FILENO);
125 /* Close the utility's file descriptors. */
127 (void)close(input[0]);
129 (void)close(input[1]);
130 (void)close(output[0]);
131 (void)close(output[1]);
133 if ((name = strrchr(O_STR(sp, O_SHELL), '/')) == NULL)
134 name = O_STR(sp, O_SHELL);
138 INT2CHAR(sp, cmd, STRLEN(cmd)+1, np, nlen);
139 execl(O_STR(sp, O_SHELL), name, "-c", np, (char *)NULL);
140 msgq_str(sp, M_SYSERR, O_STR(sp, O_SHELL), "execl: %s");
143 default: /* Parent-reader, parent-writer. */
144 /* Close the pipe ends neither parent will use. */
146 (void)close(input[0]);
147 (void)close(output[1]);
152 * FILTER_RBANG, FILTER_READ:
154 * Reading is the simple case -- we don't need a parent writer,
155 * so the parent reads the output from the read end of the output
156 * pipe until it finishes, then waits for the child. Ex_readfp
157 * appends to the MARK, and closes ofp.
159 * For FILTER_RBANG, there is nothing to write to the utility.
160 * Make sure it doesn't wait forever by closing its standard
164 * Set the return cursor to the last line read in for FILTER_READ.
165 * Historically, this behaves differently from ":r file" command,
166 * which leaves the cursor at the first line read in. Check to
167 * make sure that it's not past EOF because we were reading into an
170 if (ftype == FILTER_RBANG || ftype == FILTER_READ) {
171 if (ftype == FILTER_RBANG)
172 (void)close(input[1]);
174 if (ex_readfp(sp, "filter", ofp, fm, &nread, 1))
176 sp->rptlines[L_ADDED] += nread;
177 if (ftype == FILTER_READ) {
187 * FILTER_BANG, FILTER_WRITE
189 * Here we need both a reader and a writer. Temporary files are
190 * expensive and we'd like to avoid disk I/O. Using pipes has the
191 * obvious starvation conditions. It's done as follows:
199 * read lines into the file
202 * read and display lines
206 * We get away without locking the underlying database because we know
207 * that none of the records that we're reading will be modified until
208 * after we've read them. This depends on the fact that the current
209 * B+tree implementation doesn't balance pages or similar things when
210 * it inserts new records. When the DB code has locking, we should
211 * treat vi as if it were multiple applications sharing a database, and
212 * do the required locking. If necessary a work-around would be to do
213 * explicit locking in the line.c:db_get() code, based on the flag set
216 F_SET(sp->ep, F_MULTILOCK);
217 switch (parent_writer_pid = fork()) {
218 case -1: /* Error. */
219 msgq(sp, M_SYSERR, "fork");
220 (void)close(input[1]);
221 (void)close(output[0]);
224 case 0: /* Parent-writer. */
226 * Write the selected lines to the write end of the input
227 * pipe. This instance of ifp is closed by ex_writefp.
229 (void)close(output[0]);
230 if ((ifp = fdopen(input[1], "w")) == NULL)
232 _exit(ex_writefp(sp, "filter", ifp, fm, tm, NULL, NULL, 1));
235 default: /* Parent-reader. */
236 (void)close(input[1]);
237 if (ftype == FILTER_WRITE) {
239 * Read the output from the read end of the output
240 * pipe and display it. Filter_ldisplay closes ofp.
242 if (filter_ldisplay(sp, ofp))
246 * Read the output from the read end of the output
247 * pipe. Ex_readfp appends to the MARK and closes
250 if (ex_readfp(sp, "filter", ofp, tm, &nread, 1))
252 sp->rptlines[L_ADDED] += nread;
255 /* Wait for the parent-writer. */
257 (long)parent_writer_pid, "parent-writer", 0, 1))
260 /* Delete any lines written to the utility. */
261 if (rval == 0 && ftype == FILTER_BANG &&
262 (cut(sp, NULL, fm, tm, CUT_LINEMODE) ||
263 del(sp, fm, tm, 1))) {
269 * If the filter had no output, we may have just deleted
270 * the cursor. Don't do any real error correction, we'll
271 * try and recover later.
273 if (rp->lno > 1 && !db_exist(sp, rp->lno))
277 F_CLR(sp->ep, F_MULTILOCK);
281 * Ignore errors on vi file reads, to make reads prettier. It's
282 * completely inconsistent, and historic practice.
284 uwait: INT2CHAR(sp, cmd, STRLEN(cmd) + 1, np, nlen);
285 return (proc_wait(sp, (long)utility_pid, np,
286 ftype == FILTER_READ && F_ISSET(sp, SC_VI) ? 1 : 0, 0) || rval);
291 * Display output from a utility.
294 * Historically, the characters were passed unmodified to the terminal.
295 * We use the ex print routines to make sure they're printable.
298 filter_ldisplay(SCR *sp, FILE *fp)
306 for (exp = EXP(sp); !ex_getline(sp, fp, &len) && !INTERRUPTED(sp);) {
307 FILE2INT5(sp, exp->ibcw, exp->ibp, len, wp, wlen);
308 if (ex_ldisplay(sp, wp, wlen, 0, 0))
312 msgq(sp, M_SYSERR, "filter read");