gno/bin/less/os.c

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/*
* Operating system dependent routines.
*
* Most of the stuff in here is based on Unix, but an attempt
* has been made to make things work on other operating systems.
* This will sometimes result in a loss of functionality, unless
* someone rewrites code specifically for the new operating system.
*
* The makefile provides defines to decide whether various
* Unix features are present.
*/
#pragma noroot
#include <stdio.h>
#include <string.h>
#include <signal.h>
#include <setjmp.h>
#include "less.h"
#ifdef _ORCAC_
segment "LoadSegONE";
#include <fcntl.h>
#endif
/*
* BSD setjmp() saves (and longjmp() restores) the signal mask.
* This costs a system call or two per setjmp(), so if possible we clear the
* signal mask with sigsetmask(), and use _setjmp()/_longjmp() instead.
* On other systems, setjmp() doesn't affect the signal mask and so
* _setjmp() does not exist; we just use setjmp().
*/
#if HAS__SETJMP && SIGSETMASK
#define SET_JUMP _setjmp
#define LONG_JUMP _longjmp
#else
#define SET_JUMP setjmp
#define LONG_JUMP longjmp
#endif
extern char *getenv(char *);
public int reading;
static jmp_buf read_label;
/*
* Like read() system call, but is deliberately interruptible.
* A call to intread() from a signal handler will interrupt
* any pending iread().
*/
public int iread(fd, buf, len)
int fd;
char *buf;
unsigned int len;
{
register int n;
if (SET_JUMP(read_label))
{
/*
* We jumped here from intread.
*/
reading = 0;
#if SIGSETMASK
sigsetmask(0);
#endif
return (READ_INTR);
}
flush();
reading = 1;
n = read(fd, buf, len);
reading = 0;
if (n < 0)
return (-1);
return (n);
}
/*
* Interrupt a pending iread().
*/
public void
intread(void)
{
LONG_JUMP(read_label, 1);
}
#if GET_TIME
public long
get_time(void)
{
long t;
time(&t);
return (t);
}
#endif
/*
* errno_message: Return an error message based on the value of "errno".
*/
#if PERROR
extern char *sys_errlist[];
extern int sys_nerr;
extern int errno;
public char *
errno_message(filename)
char *filename;
{
register char *p;
register char *m;
char msg[16];
if (errno < sys_nerr)
p = sys_errlist[errno];
else
{
sprintf(msg, "Error %d", errno);
p = msg;
}
m = (char *) ecalloc(strlen(filename) + strlen(p) + 3, sizeof(char));
sprintf(m, "%s: %s", filename, p);
return (m);
}
#else
public char *
errno_message(filename)
char *filename;
{
register char *m;
static char msg[] = ": cannot open";
m = (char *) ecalloc(strlen(filename) + sizeof(msg), sizeof(char));
strcpy(m, filename);
strcat(m, msg);
return (m);
}
#endif