1*0Sstevel@tonic-gate /* 2*0Sstevel@tonic-gate * Copyright 2004 Sun Microsystems, Inc. All rights reserved. 3*0Sstevel@tonic-gate * Use is subject to license terms. 4*0Sstevel@tonic-gate */ 5*0Sstevel@tonic-gate 6*0Sstevel@tonic-gate #pragma ident "%Z%%M% %I% %E% SMI" 7*0Sstevel@tonic-gate 8*0Sstevel@tonic-gate /* 9*0Sstevel@tonic-gate * Pager: Routines to create a "more" running out of a particular file 10*0Sstevel@tonic-gate * descriptor. 11*0Sstevel@tonic-gate * 12*0Sstevel@tonic-gate * Copyright 1987, 1988 by MIT Student Information Processing Board 13*0Sstevel@tonic-gate * 14*0Sstevel@tonic-gate * For copyright information, see copyright.h. 15*0Sstevel@tonic-gate */ 16*0Sstevel@tonic-gate 17*0Sstevel@tonic-gate #include "ss_internal.h" 18*0Sstevel@tonic-gate #include "copyright.h" 19*0Sstevel@tonic-gate #include <stdio.h> 20*0Sstevel@tonic-gate #include <sys/types.h> 21*0Sstevel@tonic-gate #include <sys/file.h> 22*0Sstevel@tonic-gate #include <signal.h> 23*0Sstevel@tonic-gate #include <errno.h> 24*0Sstevel@tonic-gate 25*0Sstevel@tonic-gate static char MORE[] = "more"; 26*0Sstevel@tonic-gate extern char *_ss_pager_name; 27*0Sstevel@tonic-gate extern char *getenv(); 28*0Sstevel@tonic-gate 29*0Sstevel@tonic-gate /* 30*0Sstevel@tonic-gate * this needs a *lot* of work.... 31*0Sstevel@tonic-gate * 32*0Sstevel@tonic-gate * run in same process 33*0Sstevel@tonic-gate * handle SIGINT sensibly 34*0Sstevel@tonic-gate * allow finer control -- put-page-break-here 35*0Sstevel@tonic-gate */ 36*0Sstevel@tonic-gate void ss_page_stdin(); 37*0Sstevel@tonic-gate 38*0Sstevel@tonic-gate #ifndef NO_FORK 39*0Sstevel@tonic-gate int ss_pager_create() 40*0Sstevel@tonic-gate { 41*0Sstevel@tonic-gate int filedes[2]; 42*0Sstevel@tonic-gate 43*0Sstevel@tonic-gate if (pipe(filedes) != 0) 44*0Sstevel@tonic-gate return(-1); 45*0Sstevel@tonic-gate 46*0Sstevel@tonic-gate switch(fork()) { 47*0Sstevel@tonic-gate case -1: 48*0Sstevel@tonic-gate return(-1); 49*0Sstevel@tonic-gate case 0: 50*0Sstevel@tonic-gate /* 51*0Sstevel@tonic-gate * Child; dup read half to 0, close all but 0, 1, and 2 52*0Sstevel@tonic-gate */ 53*0Sstevel@tonic-gate if (dup2(filedes[0], 0) == -1) 54*0Sstevel@tonic-gate exit(1); 55*0Sstevel@tonic-gate ss_page_stdin(); 56*0Sstevel@tonic-gate default: 57*0Sstevel@tonic-gate /* 58*0Sstevel@tonic-gate * Parent: close "read" side of pipe, return 59*0Sstevel@tonic-gate * "write" side. 60*0Sstevel@tonic-gate */ 61*0Sstevel@tonic-gate (void) close(filedes[0]); 62*0Sstevel@tonic-gate return(filedes[1]); 63*0Sstevel@tonic-gate } 64*0Sstevel@tonic-gate } 65*0Sstevel@tonic-gate #else /* don't fork */ 66*0Sstevel@tonic-gate int ss_pager_create() 67*0Sstevel@tonic-gate { 68*0Sstevel@tonic-gate int fd; 69*0Sstevel@tonic-gate fd = open("/dev/tty", O_WRONLY, 0); 70*0Sstevel@tonic-gate return fd; 71*0Sstevel@tonic-gate } 72*0Sstevel@tonic-gate #endif 73*0Sstevel@tonic-gate 74*0Sstevel@tonic-gate void ss_page_stdin() 75*0Sstevel@tonic-gate { 76*0Sstevel@tonic-gate int i; 77*0Sstevel@tonic-gate #ifdef POSIX_SIGNALS 78*0Sstevel@tonic-gate struct sigaction sa; 79*0Sstevel@tonic-gate sigset_t mask; 80*0Sstevel@tonic-gate #endif 81*0Sstevel@tonic-gate /* 82*0Sstevel@tonic-gate * Close all fd's, excepting stdin/stdout/stderr 83*0Sstevel@tonic-gate */ 84*0Sstevel@tonic-gate closefrom(3); 85*0Sstevel@tonic-gate 86*0Sstevel@tonic-gate #ifdef POSIX_SIGNALS 87*0Sstevel@tonic-gate sa.sa_handler = SIG_DFL; 88*0Sstevel@tonic-gate sigemptyset(&sa.sa_mask); 89*0Sstevel@tonic-gate sa.sa_flags = 0; 90*0Sstevel@tonic-gate sigaction(SIGINT, &sa, (struct sigaction *)0); 91*0Sstevel@tonic-gate #else 92*0Sstevel@tonic-gate (void) signal(SIGINT, SIG_DFL); 93*0Sstevel@tonic-gate #endif 94*0Sstevel@tonic-gate { 95*0Sstevel@tonic-gate #ifdef POSIX_SIGNALS 96*0Sstevel@tonic-gate sigemptyset(&mask); 97*0Sstevel@tonic-gate sigaddset(&mask, SIGINT); 98*0Sstevel@tonic-gate sigprocmask(SIG_UNBLOCK, &mask, (sigset_t *)0); 99*0Sstevel@tonic-gate #else 100*0Sstevel@tonic-gate int mask = sigblock(0); 101*0Sstevel@tonic-gate mask &= ~sigmask(SIGINT); 102*0Sstevel@tonic-gate sigsetmask(mask); 103*0Sstevel@tonic-gate #endif 104*0Sstevel@tonic-gate } 105*0Sstevel@tonic-gate if (_ss_pager_name == (char *)NULL) { 106*0Sstevel@tonic-gate if ((_ss_pager_name = getenv("PAGER")) == (char *)NULL) 107*0Sstevel@tonic-gate _ss_pager_name = MORE; 108*0Sstevel@tonic-gate } 109*0Sstevel@tonic-gate (void) execlp(_ss_pager_name, _ss_pager_name, (char *) NULL); 110*0Sstevel@tonic-gate { 111*0Sstevel@tonic-gate /* minimal recovery if pager program isn't found */ 112*0Sstevel@tonic-gate char buf[80]; 113*0Sstevel@tonic-gate register int n; 114*0Sstevel@tonic-gate while ((n = read(0, buf, 80)) > 0) 115*0Sstevel@tonic-gate write(1, buf, n); 116*0Sstevel@tonic-gate } 117*0Sstevel@tonic-gate exit(errno); 118*0Sstevel@tonic-gate } 119