92 lines
1.7 KiB
C
92 lines
1.7 KiB
C
/*
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* Pager: Routines to create a "more" running out of a particular file
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* descriptor.
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*
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* Copyright 1987, 1988 by MIT Student Information Processing Board
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*
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* For copyright information, see copyright.h.
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*/
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#include "ss_internal.h"
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#include "copyright.h"
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#include <stdio.h>
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#include <sys/file.h>
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#include <signal.h>
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#include <unistd.h>
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static char MORE[] = "more";
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extern char *_ss_pager_name;
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extern char *getenv();
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extern int errno;
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/*
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* this needs a *lot* of work....
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*
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* run in same process
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* handle SIGINT sensibly
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* allow finer control -- put-page-break-here
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*/
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void ss_page_stdin();
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#ifndef NO_FORK
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int ss_pager_create()
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{
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int filedes[2];
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if (pipe(filedes) != 0)
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return(-1);
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switch(fork()) {
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case -1:
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return(-1);
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case 0:
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/*
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* Child; dup read half to 0, close all but 0, 1, and 2
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*/
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if (dup2(filedes[0], 0) == -1)
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exit(1);
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ss_page_stdin();
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default:
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/*
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* Parent: close "read" side of pipe, return
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* "write" side.
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*/
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(void) close(filedes[0]);
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return(filedes[1]);
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}
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}
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#else /* don't fork */
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int ss_pager_create()
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{
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int fd;
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fd = open("/dev/tty", O_WRONLY, 0);
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return fd;
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}
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#endif
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void ss_page_stdin()
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{
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int i;
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for (i = 3; i < 32; i++)
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(void) close(i);
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(void) signal(SIGINT, SIG_DFL);
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{
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register int mask = sigblock(0);
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mask &= ~sigmask(SIGINT);
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sigsetmask(mask);
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}
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if (_ss_pager_name == (char *)NULL) {
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if ((_ss_pager_name = getenv("PAGER")) == (char *)NULL)
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_ss_pager_name = MORE;
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}
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(void) execlp(_ss_pager_name, _ss_pager_name, (char *) NULL);
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{
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/* minimal recovery if pager program isn't found */
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char buf[80];
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register int n;
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while ((n = read(0, buf, 80)) > 0)
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write(1, buf, n);
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}
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exit(errno);
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}
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