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Diffstat (limited to 'contrib/nvi/ex/ex_filter.c')
| -rw-r--r-- | contrib/nvi/ex/ex_filter.c | 316 |
1 files changed, 316 insertions, 0 deletions
diff --git a/contrib/nvi/ex/ex_filter.c b/contrib/nvi/ex/ex_filter.c new file mode 100644 index 0000000..2e86e58 --- /dev/null +++ b/contrib/nvi/ex/ex_filter.c @@ -0,0 +1,316 @@ +/*- + * 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[] = "@(#)ex_filter.c 10.34 (Berkeley) 10/23/96"; +#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 *)); + +/* + * 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 *, enum filtertype)); + */ +int +ex_filter(sp, cmdp, fm, tm, rp, cmd, ftype) + SCR *sp; + EXCMD *cmdp; + MARK *fm, *tm, *rp; + char *cmd; + enum filtertype ftype; +{ + FILE *ifp, *ofp; + pid_t parent_writer_pid, utility_pid; + recno_t nread; + int input[2], output[2], rval; + char *name; + + 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. */ + switch (utility_pid = vfork()) { + case -1: /* Error. */ + msgq(sp, M_SYSERR, "vfork"); +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); + 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", cmd, 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]); + break; + } + + /* + * 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: return (proc_wait(sp, (long)utility_pid, cmd, + ftype == FILTER_READ && F_ISSET(sp, SC_VI) ? 1 : 0, 0) || rval); +} + +/* + * 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(sp, fp) + SCR *sp; + FILE *fp; +{ + size_t len; + + EX_PRIVATE *exp; + + for (exp = EXP(sp); !ex_getline(sp, fp, &len) && !INTERRUPTED(sp);) + if (ex_ldisplay(sp, exp->ibp, len, 0, 0)) + break; + if (ferror(fp)) + msgq(sp, M_SYSERR, "filter read"); + (void)fclose(fp); + return (0); +} |
