[unix-history] / usr / src / usr.bin / touch / touch.c

/*
* Copyright (c) 1988 Regents of the University of California.
* All rights reserved.
*
* %sccs.include.redist.c%
*/

#ifndef lint
char copyright[] =
"@(#) Copyright (c) 1988 Regents of the University of California.\n\
All rights reserved.\n";
#endif /* not lint */

#ifndef lint
static char sccsid[] = "@(#)touch.c     5.1 (Berkeley) %G%";
#endif /* not lint */

/*
* Attempt to set the modify date of a file to the current date.  If the
* file exists, read and write its first character.  If the file doesn't
* exist, create it, unless -c option prevents it.  If the file is read-only,
* -f forces chmod'ing and touch'ing.
*/
#include <sys/types.h>
#include <sys/stat.h>

#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

static int      dontcreate;     /* set if -c option */
static int      force;          /* set if -f option */

void    err __P((const char *, ...));
int     readwrite __P((char *, off_t));
int     touch __P((char *));
__dead  void usage __P((void));

int
main(argc, argv)
       int argc;
       char *argv[];
{
       int ch, retval;

       dontcreate = force = retval = 0;
       while ((ch = getopt(argc, argv, "cf")) != EOF)
               switch((char)ch) {
               case 'c':
                       dontcreate = 1;
                       break;
               case 'f':
                       force = 1;
                       break;
               case '?':
               default:
                       usage();
               }
       if (!*(argv += optind))
               usage();
       do {
               retval |= touch(*argv);
       } while (*++argv);
       exit(retval);
}

int
touch(filename)
       char *filename;
{
       struct stat sb;

       if (stat(filename, &sb) == -1) {
               if (!dontcreate)
                       return (readwrite(filename, (off_t)0));
               err("%s: %s", filename, strerror(ENOENT));
               return (1);
       }
       if ((sb.st_mode & S_IFMT) != S_IFREG) {
               err("%s: %s", filename, strerror(EFTYPE));
               return (1);
       }
       if (!access(filename, R_OK | W_OK))
               return (readwrite(filename, sb.st_size));
       if (force) {
               int retval;

               if (chmod(filename, DEFFILEMODE)) {
                       err("%s: add permissions: %s",
                           filename, strerror(errno));
                       return (1);
               }
               retval = readwrite(filename, sb.st_size);
               if (chmod(filename, sb.st_mode)) {
                       err("%s: restore permissions: %s",
                           filename, strerror(errno));
                       return (1);
               }
               return (retval);
       }
       err("%s: cannot touch\n", filename);
       return (1);
}

int
readwrite(filename, size)
       char *filename;
       off_t size;
{
       int fd;
       char first;

       if (size) {
               fd = open(filename, O_RDWR, 0);
               if (fd == -1)
                       goto error;
               if (read(fd, &first, 1) != 1)
                       goto error;
               if (lseek(fd, (off_t)0, SEEK_SET) == -1)
                       goto error;
               if (write(fd, &first, 1) != 1)
                       goto error;
       } else {
               fd = creat(filename, DEFFILEMODE);
               if (fd == -1)
                       goto error;
       }
       if (close(fd) == -1) {
error:          err("%s: %s", filename, strerror(errno));
               return (1);
       }
       return (0);
}

__dead void
usage()
{
       fprintf(stderr, "usage: touch [-cf] file ...\n");
       exit(1);
}

#if __STDC__
#include <stdarg.h>
#else
#include <varargs.h>
#endif

void
#if __STDC__
err(const char *fmt, ...)
#else
err(fmt, va_alist)
       char *fmt;
       va_dcl
#endif
{
       va_list ap;
#if __STDC__
       va_start(ap, fmt);
#else
       va_start(ap);
#endif
       (void)fprintf(stderr, "touch: ");
       (void)vfprintf(stderr, fmt, ap);
       va_end(ap);
       (void)fprintf(stderr, "\n");
}