From 464df1d5e5ab1322e2dd0a7796939fff1aeefa9a Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 7 Apr 2024 17:49:25 +0200 Subject: Adding upstream version 1.47.0. Signed-off-by: Daniel Baumann --- lib/ss/pager.c | 152 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 152 insertions(+) create mode 100644 lib/ss/pager.c (limited to 'lib/ss/pager.c') diff --git a/lib/ss/pager.c b/lib/ss/pager.c new file mode 100644 index 0000000..ba32b20 --- /dev/null +++ b/lib/ss/pager.c @@ -0,0 +1,152 @@ +/* + * Pager: Routines to create a "more" running out of a particular file + * descriptor. + * + * Copyright 1987, 1988 by MIT Student Information Processing Board + * + * Permission to use, copy, modify, and distribute this software and + * its documentation for any purpose is hereby granted, provided that + * the names of M.I.T. and the M.I.T. S.I.P.B. not be used in + * advertising or publicity pertaining to distribution of the software + * without specific, written prior permission. M.I.T. and the + * M.I.T. S.I.P.B. make no representations about the suitability of + * this software for any purpose. It is provided "as is" without + * express or implied warranty. + */ + +#include "config.h" +#ifdef HAVE_UNISTD_H +#include +#endif +#ifdef HAVE_ERRNO_H +#include +#endif + +#include "ss_internal.h" +#include +#include +#include +#include +#ifdef HAVE_SYS_PRCTL_H +#include +#else +#define PR_GET_DUMPABLE 3 +#endif +#if (!defined(HAVE_PRCTL) && defined(linux)) +#include +#endif + +static char MORE[] = "more"; +extern char *getenv PROTOTYPE((const char *)); + +char *ss_safe_getenv(const char *arg) +{ + if ((getuid() != geteuid()) || (getgid() != getegid())) + return NULL; +#if HAVE_PRCTL + if (prctl(PR_GET_DUMPABLE, 0, 0, 0, 0) == 0) + return NULL; +#else +#if (defined(linux) && defined(SYS_prctl)) + if (syscall(SYS_prctl, PR_GET_DUMPABLE, 0, 0, 0, 0) == 0) + return NULL; +#endif +#endif + +#if defined(HAVE_SECURE_GETENV) + return secure_getenv(arg); +#elif defined(HAVE___SECURE_GETENV) + return __secure_getenv(arg); +#else + return getenv(arg); +#endif +} + +/* + * this needs a *lot* of work.... + * + * run in same process + * handle SIGINT sensibly + * allow finer control -- put-page-break-here + */ + +#ifndef NO_FORK +int ss_pager_create(void) +{ + int filedes[2]; + + if (pipe(filedes) != 0) + return(-1); + + switch(fork()) { + case -1: + return(-1); + case 0: + /* + * Child; dup read half to 0, close all but 0, 1, and 2 + */ + if (dup2(filedes[0], 0) == -1) + exit(1); + ss_page_stdin(); + default: + /* + * Parent: close "read" side of pipe, return + * "write" side. + */ + (void) close(filedes[0]); + return(filedes[1]); + } +} +#else /* don't fork */ +int ss_pager_create() +{ + int fd; + fd = open("/dev/tty", O_WRONLY, 0); + return fd; +} +#endif + +static int write_all(int fd, char *buf, size_t count) +{ + ssize_t ret; + int c = 0; + + while (count > 0) { + ret = write(fd, buf, count); + if (ret < 0) { + if ((errno == EAGAIN) || (errno == EINTR)) + continue; + return -1; + } + count -= ret; + buf += ret; + c += ret; + } + return c; +} + +void ss_page_stdin(void) +{ + int i; + sigset_t mask; + + for (i = 3; i < 32; i++) + (void) close(i); + (void) signal(SIGINT, SIG_DFL); + sigprocmask(SIG_BLOCK, 0, &mask); + sigdelset(&mask, SIGINT); + sigprocmask(SIG_SETMASK, &mask, 0); + if (_ss_pager_name == (char *)NULL) { + if ((_ss_pager_name = ss_safe_getenv("PAGER")) == (char *)NULL) + _ss_pager_name = MORE; + } + (void) execlp(_ss_pager_name, _ss_pager_name, (char *) NULL); + { + /* minimal recovery if pager program isn't found */ + char buf[80]; + register int n; + while ((n = read(0, buf, 80)) > 0) + write_all(1, buf, n); + } + exit(errno); +} -- cgit v1.2.3