usr.bin/more/os.c

/*
 * Copyright (c) 1988 Mark Nudleman
 * Copyright (c) 1988 Regents of the University of California.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by the University of
 *      California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#ifndef lint
static char sccsid[] = "@(#)os.c        5.12 (Berkeley) 3/1/91";
#endif /* not lint */

/*
 * 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.
 */

#include <sys/param.h>
#include <sys/stat.h>
#include <sys/file.h>
#include <signal.h>
#include <setjmp.h>
#include <stdio.h>
#include <less.h>
#include "pathnames.h"

int reading;

extern int screen_trashed;

static jmp_buf read_label;

/*
 * Pass the specified command to a shell to be executed.
 * Like plain "system()", but handles resetting terminal modes, etc.
 */
lsystem(cmd)
        char *cmd;
{
        int inp;
        char cmdbuf[256];
        char *shell, *getenv();

        /*
         * Print the command which is to be executed,
         * unless the command starts with a "-".
         */
        if (cmd[0] == '-')
                cmd++;
        else
        {
                lower_left();
                clear_eol();
                putstr("!");
                putstr(cmd);
                putstr("\n");
        }

        /*
         * De-initialize the terminal and take out of raw mode.
         */
        deinit();
        flush();
        raw_mode(0);

        /*
         * Restore signals to their defaults.
         */
        init_signals(0);

        /*
         * Force standard input to be the terminal, "/dev/tty",
         * even if less's standard input is coming from a pipe.
         */
        inp = dup(0);
        (void)close(0);
        if (open(_PATH_TTY, O_RDONLY, 0) < 0)
                (void)dup(inp);

        /*
         * Pass the command to the system to be executed.
         * If we have a SHELL environment variable, use
         * <$SHELL -c "command"> instead of just <command>.
         * If the command is empty, just invoke a shell.
         */
        if ((shell = getenv("SHELL")) != NULL && *shell != '\0')
        {
                if (*cmd == '\0')
                        cmd = shell;
                else
                {
                        (void)sprintf(cmdbuf, "%s -c \"%s\"", shell, cmd);
                        cmd = cmdbuf;
                }
        }
        if (*cmd == '\0')
                cmd = "sh";

        (void)system(cmd);

        /*
         * Restore standard input, reset signals, raw mode, etc.
         */
        (void)close(0);
        (void)dup(inp);
        (void)close(inp);

        init_signals(1);
        raw_mode(1);
        init();
        screen_trashed = 1;
#if defined(SIGWINCH) || defined(SIGWIND)
        /*
         * Since we were ignoring window change signals while we executed
         * the system command, we must assume the window changed.
         */
        winch();
#endif
}

/*
 * Like read() system call, but is deliberately interruptable.
 * A call to intread() from a signal handler will interrupt
 * any pending iread().
 */
iread(fd, buf, len)
        int fd;
        char *buf;
        int len;
{
        register int n;

        if (setjmp(read_label))
                /*
                 * We jumped here from intread.
                 */
                return (READ_INTR);

        flush();
        reading = 1;
        n = read(fd, buf, len);
        reading = 0;
        if (n < 0)
                return (-1);
        return (n);
}

intread()
{
        (void)sigsetmask(0L);
        longjmp(read_label, 1);
}

/*
 * Expand a filename, substituting any environment variables, etc.
 * The implementation of this is necessarily very operating system
 * dependent.  This implementation is unabashedly only for Unix systems.
 */
FILE *popen();

char *
glob(filename)
        char *filename;
{
        FILE *f;
        char *p;
        int ch;
        char *cmd, *malloc(), *getenv();
        static char buffer[MAXPATHLEN];

        if (filename[0] == '#')
                return (filename);

        /*
         * We get the shell to expand the filename for us by passing
         * an "echo" command to the shell and reading its output.
         */
        p = getenv("SHELL");
        if (p == NULL || *p == '\0')
        {
                /*
                 * Read the output of <echo filename>.
                 */
                cmd = malloc((u_int)(strlen(filename)+8));
                if (cmd == NULL)
                        return (filename);
                (void)sprintf(cmd, "echo \"%s\"", filename);
        } else
        {
                /*
                 * Read the output of <$SHELL -c "echo filename">.
                 */
                cmd = malloc((u_int)(strlen(p)+12));
                if (cmd == NULL)
                        return (filename);
                (void)sprintf(cmd, "%s -c \"echo %s\"", p, filename);
        }

        if ((f = popen(cmd, "r")) == NULL)
                return (filename);
        free(cmd);

        for (p = buffer;  p < &buffer[sizeof(buffer)-1];  p++)
        {
                if ((ch = getc(f)) == '\n' || ch == EOF)
                        break;
                *p = ch;
        }
        *p = '\0';
        (void)pclose(f);
        return(buffer);
}

char *
bad_file(filename, message, len)
        char *filename, *message;
        u_int len;
{
        extern int errno;
        struct stat statbuf;
        char *strcat(), *strerror();

        if (stat(filename, &statbuf) < 0) {
                (void)sprintf(message, "%s: %s", filename, strerror(errno));
                return(message);
        }
        if ((statbuf.st_mode & S_IFMT) == S_IFDIR) {
                static char is_dir[] = " is a directory";

                strtcpy(message, filename, (int)(len-sizeof(is_dir)-1));
                (void)strcat(message, is_dir);
                return(message);
        }
        return((char *)NULL);
}

/*
 * Copy a string, truncating to the specified length if necessary.
 * Unlike strncpy(), the resulting string is guaranteed to be null-terminated.
 */
strtcpy(to, from, len)
        char *to, *from;
        int len;
{
        char *strncpy();

        (void)strncpy(to, from, (int)len);
        to[len-1] = '\0';
}