written by Mark Horton; add Berkeley copyright

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

/*
* Copyright (c) 1988 Regents of the University of California.
* All rights reserved.
*
* Redistribution and use in source and binary forms are permitted
* provided that the above copyright notice and this paragraph are
* duplicated in all such forms and that any documentation,
* advertising materials, and other materials related to such
* distribution and use acknowledge that the software was developed
* by the University of California, Berkeley.  The name of the
* University may not be used to endorse or promote products derived
* from this software without specific prior written permission.
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
* WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
*/

#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     4.7 (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/file.h>
#include <sys/stat.h>
#include <stdio.h>

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

main(argc, argv)
       int argc;
       char **argv;
{
       extern int optind;
       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);
}

touch(filename)
       char *filename;
{
       struct stat statbuffer;

       if (stat(filename, &statbuffer) == -1) {
               if (!dontcreate)
                       return(readwrite(filename, 0L));
               fprintf(stderr, "touch: %s: does not exist\n", filename);
               return(1);
       }
       if ((statbuffer.st_mode & S_IFMT) != S_IFREG) {
               fprintf(stderr, "touch: %s: can only touch regular files\n",
                   filename);
               return(1);
       }
       if (!access(filename, R_OK | W_OK))
               return(readwrite(filename,statbuffer.st_size));
       if (force) {
               int retval;

               if (chmod(filename, 0666)) {
                       fprintf(stderr, "touch: %s: couldn't chmod: ",
                           filename);
                       perror((char *)NULL);
                       return(1);
               }
               retval = readwrite(filename, statbuffer.st_size);
               if (chmod(filename, statbuffer.st_mode)) {
                       fprintf(stderr, "touch: %s: couldn't chmod back: ",
                           filename);
                       perror((char *)NULL);
                       return(1);
               }
               return(retval);
       }
       fprintf(stderr, "touch: %s: cannot touch\n", filename);
       return(1);
}

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

       if (size) {
               filedescriptor = open(filename, O_RDWR, 0);
               if (filedescriptor == -1) {
error:                  fprintf(stderr, "touch: %s: ", filename);
                       perror((char *)NULL);
                       return(1);
               }
               if (read(filedescriptor, &first, 1) != 1)
                       goto error;
               if (lseek(filedescriptor, 0L, 0) == -1)
                       goto error;
               if (write(filedescriptor, &first, 1) != 1)
                       goto error;
       } else {
               filedescriptor = creat(filename, 0666);
               if (filedescriptor == -1)
                       goto error;
       }
       if (close(filedescriptor) == -1)
               goto error;
       return(0);
}

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