if -r and not -h use lstat on recursive descent; Harry Rubin

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

/*
* Copyright (c) 1988 The Regents of the University of California.
* All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* David Hitz of Auspex Systems Inc.
*
* 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 The Regents of the University of California.\n\
All rights reserved.\n";
#endif /* not lint */

#ifndef lint
static char sccsid[] = "@(#)cp.c        5.8 (Berkeley) %G%";
#endif /* not lint */

/*
* cp copies source files to target files.
* 
* The global path_t structures "to" and "from" always contain paths to the
* current source and target files, respectively.  Since cp does not change
* directories, these paths can be either absolute or dot-realative.
* 
* The basic algorithm is to initialize "to" and "from", and then call the
* recursive copy() function to do the actual work.  If "from" is a file,
* copy copies the data.  If "from" is a directory, copy creates the
* corresponding "to" directory, and calls itself recursively on all of
* the entries in the "from" directory.
*/

#include <sys/param.h>
#include <sys/stat.h>
#include <sys/file.h>
#include <sys/dir.h>
#include <sys/time.h>

#include <stdio.h>
#include <errno.h>
#include <strings.h>

typedef struct {
       char    *p_path;        /* pointer to the start of a path. */
       char    *p_end;         /* pointer to NULL at end of path. */
} path_t;

#define type(st)        ((st).st_mode&S_IFMT)

char *path_append(), *path_basename();
void path_restore();

int exit_val;
int interactive_flag, preserve_flag, recursive_flag;
int (*statfcn)();                       /* stat function to use */
char *buf;                              /* I/O; malloc for best alignment. */
char from_buf[MAXPATHLEN + 1],          /* source path buffer */
    to_buf[MAXPATHLEN + 1];            /* target path buffer */
path_t from = {from_buf, from_buf};
path_t to = {to_buf, to_buf};

main(argc, argv)
       int argc;
       char **argv;
{
       extern int optind, errno;
       struct stat to_stat;
       register int c, r;
       int force_flag, symfollow, lstat(), stat();
       char *old_to, *malloc();

       force_flag = symfollow = 0;
       while ((c = getopt(argc, argv, "Rfhipr")) != EOF) {
       switch ((char)c) {
               case 'f':
                       force_flag = 1;
                       break;
               case 'h':
                       symfollow = 1;
                       break;
               case 'i':
                       interactive_flag = isatty(fileno(stdin));
                       break;
               case 'p':
                       preserve_flag = 1;
                       (void)umask(0);
                       break;
               case 'r':
               case 'R':
                       recursive_flag = 1;
                       break;
               case '?':
               default:
                       usage();
                       break;
               }
       }
       argc -= optind;
       argv += optind;

       if (argc < 2)
               usage();

       if (force_flag)
               interactive_flag = 0;

       buf = (char *)malloc(MAXBSIZE);
       if (!buf) {
               (void)fprintf(stderr, "cp: out of space.\n");
               exit(1);
       }

       /* consume last argument first. */
       if (!path_set(&to, argv[--argc]))
               exit(exit_val);

       statfcn = symfollow || !recursive_flag ? stat : lstat;

       /*
        * Cp has two distinct cases:
        *
        * Case (1)       $ cp [-rip] source target
        *
        * Case (2)       $ cp [-rip] source1 ... directory
        *
        * In both cases, source can be either a file or a directory.
        *
        * In (1), the target becomes a copy of the source. That is, if the
        * source is a file, the target will be a file, and likewise for
        * directories.
        *
        * In (2), the real target is not directory, but "directory/source".
        */

       r = stat(to.p_path, &to_stat);
       if (r == -1 && errno != ENOENT) {
               error(to.p_path);
               exit(1);
       }
       if (r == -1 || type(to_stat) != S_IFDIR) {
               /*
                * Case (1).  Target is not a directory.
                */
               if (argc > 1) {
                       usage();
                       exit(1);
               }
               if (!path_set(&from, *argv))
                       exit(exit_val);
               copy();
       }
       else {
               /*
                * Case (2).  Target is a directory.
                */
               for (;; ++argv) {
                       if (!path_set(&from, *argv))
                               continue;
                       old_to = path_append(&to, path_basename(&from), -1);
                       if (!old_to)
                               continue;
                       copy();
                       if (!--argc)
                               break;
                       path_restore(&to, old_to);
               }
       }
       exit(exit_val);
}

/* copy file or directory at "from" to "to". */
copy()
{
       struct stat from_stat, to_stat;
       int dne, statval;

       statval = statfcn(from.p_path, &from_stat);
       if (statval == -1) {
               error(from.p_path);
               return;
       }

       /* not an error, but need to remember it happened */
       if (stat(to.p_path, &to_stat) == -1)
               dne = 1;
       else {
               if (to_stat.st_dev == from_stat.st_dev &&
                   to_stat.st_ino == from_stat.st_ino) {
                       (void)fprintf(stderr,
                           "cp: %s and %s are identical (not copied).\n",
                           to.p_path, from.p_path);
                       exit_val = 1;
                       return;
               }
               dne = 0;
       }

       switch(type(from_stat)) {
       case S_IFLNK:
               copy_link(!dne);
               return;
       case S_IFDIR:
               if (!recursive_flag) {
                       (void)fprintf(stderr,
                           "cp: %s is a directory (not copied).\n",
                           from.p_path);
                       exit_val = 1;
                       return;
               }
               if (dne) {
                       /*
                        * If the directory doesn't exist, create the new
                        * one with the from file mode plus owner RWX bits,
                        * modified by the umask.  Trade-off between being
                        * able to write the directory (if from directory is
                        * 555) and not causing a permissions race.  If the
                        * umask blocks owner writes cp fails.
                        */
                       if (mkdir(to.p_path, from_stat.st_mode|S_IRWXU) < 0) {
                               error(to.p_path);
                               return;
                       }
               }
               else if (type(to_stat) != S_IFDIR) {
                       (void)fprintf(stderr, "cp: %s: not a directory.\n",
                           to.p_path);
                       return;
               }
               copy_dir();
               /*
                * If not -p and directory didn't exist, set it to be the
                * same as the from directory, umodified by the umask;
                * arguably wrong, but it's been that way forever.
                */
               if (preserve_flag)
                       setfile(&from_stat, 0);
               else if (dne)
                       (void)chmod(to.p_path, from_stat.st_mode);
               break;
       case S_IFCHR:
       case S_IFBLK:
               /*
                * if recursive flag on, try and create the special device
                * otherwise copy the contents.
                */
               if (recursive_flag) {
                       copy_special(&from_stat, &to_stat);
                       if (preserve_flag)
                               setfile(&from_stat, 0);
                       return;
               }
               /* FALLTHROUGH */
       default:
               copy_file(&from_stat);
       }
}

copy_file(fs)
       struct stat *fs;
{
       register int from_fd, to_fd, rcount, wcount;

       if ((from_fd = open(from.p_path, O_RDONLY, 0)) == -1) {
               error(from.p_path);
               return;
       }

       /*
        * In the interactive case, use O_EXCL to notice existing files.
        * If the file exists, verify with the user.
        *
        * If the file DNE, create it with the mode of the from file modified
        * by the umask; arguably wrong but it makes copying executables work
        * right and it's been that way forever.  The other choice is 666
        * or'ed with the execute bits on the from file modified by the umask.
        */
       to_fd = open(to.p_path,
           (interactive_flag ? O_EXCL : 0) | O_WRONLY | O_CREAT | O_TRUNC,
           fs->st_mode);

       if (to_fd == -1 && errno == EEXIST && interactive_flag) {
               int checkch, ch;

               (void)fprintf(stderr, "overwrite %s? ", to.p_path);
               checkch = ch = getchar();
               while (ch != '\n' && ch != EOF)
                       ch = getchar();
               if (checkch != 'y')
                       return;
               /* try again. */
               to_fd = open(to.p_path, O_WRONLY | O_CREAT | O_TRUNC,
                   fs->st_mode);
       }

       if (to_fd == -1) {
               error(to.p_path);
               (void)close(from_fd);
               return;
       }

       while ((rcount = read(from_fd, buf, MAXBSIZE)) > 0) {
               wcount = write(to_fd, buf, rcount);
               if (rcount != wcount || wcount == -1) {
                       error(to.p_path);
                       break;
               }
       }
       if (rcount < 0)
               error(from.p_path);
       if (preserve_flag)
               setfile(fs, to_fd);
       (void)close(from_fd);
       (void)close(to_fd);
}

copy_dir()
{
       struct stat from_stat;
       struct direct *dp, **dir_list;
       register int dir_cnt, i;
       char *old_from, *old_to;

       dir_cnt = scandir(from.p_path, &dir_list, NULL, NULL);
       if (dir_cnt == -1) {
               (void)fprintf(stderr, "cp: can't read directory %s.\n",
                   from.p_path);
               exit_val = 1;
       }

       /*
        * Instead of handling directory entries in the order they appear
        * on disk, do non-directory files before directory files.
        * There are two reasons to do directories last.  The first is
        * efficiency.  Files tend to be in the same cylinder group as
        * their parent, whereas directories tend not to be.  Copying files
        * all at once reduces seeking.  Second, deeply nested tree's
        * could use up all the file descriptors if we didn't close one
        * directory before recursivly starting on the next.
        */
       /* copy files */
       for (i = 0; i < dir_cnt; ++i) {
               dp = dir_list[i];
               if (dp->d_namlen <= 2 && dp->d_name[0] == '.'
                   && (dp->d_name[1] == NULL || dp->d_name[1] == '.'))
                       goto done;
               old_from = path_append(&from, dp->d_name, (int)dp->d_namlen);
               if (!old_from)
                       goto done;

               if (statfcn(from.p_path, &from_stat) < 0) {
                       error(dp->d_name);
                       path_restore(&from, old_from);
                       goto done;
               }
               if (type(from_stat) == S_IFDIR) {
                       path_restore(&from, old_from);
                       continue;
               }
               old_to = path_append(&to, dp->d_name, (int)dp->d_namlen);
               if (old_to) {
                       copy();
                       path_restore(&to, old_to);
               }
               path_restore(&from, old_from);
done:           dir_list[i] = NULL;
               (void)free((char *)dp);
       }

       /* copy directories */
       for (i = 0; i < dir_cnt; ++i) {
               dp = dir_list[i];
               if (!dp)
                       continue;
               old_from = path_append(&from, dp->d_name, (int) dp->d_namlen);
               if (!old_from) {
                       (void)free((char *)dp);
                       continue;
               }
               old_to = path_append(&to, dp->d_name, (int) dp->d_namlen);
               if (!old_to) {
                       (void)free((char *)dp);
                       path_restore(&from, old_from);
                       continue;
               }
               copy();
               free((char *)dp);
               path_restore(&from, old_from);
               path_restore(&to, old_to);
       }
       free((char *)dir_list);
}

copy_link(exists)
       int exists;
{
       char link[MAXPATHLEN];

       if (readlink(from.p_path, link, sizeof(link)) == -1) {
               error(from.p_path);
               return;
       }
       if (exists && unlink(to.p_path)) {
               error(to.p_path);
               return;
       }
       if (symlink(link, to.p_path)) {
               error(link);
               return;
       }
}

copy_special(from_stat, to_stat)
       struct stat *from_stat, *to_stat;
{
       if (to_stat->st_ino != -1 && unlink(to.p_path)) {
               error(to.p_path);
               return;
       }
       if (mknod(to.p_path, from_stat->st_mode,  from_stat->st_rdev)) {
               error(to.p_path);
               return;
       }
}

setfile(fs, fd)
       register struct stat *fs;
       int fd;
{
       static struct timeval tv[2];
       static int dochown = 1;

       tv[0].tv_sec = fs->st_atime;
       tv[1].tv_sec = fs->st_mtime;
       if (utimes(to.p_path, tv))
               error(to.p_path);
       /*
        * Changing the ownership probably won't succeed, unless we're
        * root or POSIX_CHOWN_RESTRICTED is not set.  Try it last so
        * everything else gets set first.
        */
       if (fd) {
               if (fchmod(fd, fs->st_mode))
                       error(to.p_path);
               if (dochown && fchown(fd, fs->st_uid, fs->st_gid) == -1)
                       if (errno == EPERM)
                               dochown = 0;
                       else
                               error(to.p_path);
       } else {
               if (chmod(to.p_path, fs->st_mode))
                       error(to.p_path);
               if (dochown && chown(to.p_path, fs->st_uid, fs->st_gid) == -1)
                       if (errno == EPERM)
                               dochown = 0;
                       else
                               error(to.p_path);
       }
}

error(s)
       char *s;
{
       extern int errno;

       exit_val = 1;
       (void)fprintf(stderr, "cp: %s: %s\n", s, strerror(errno));
}

/********************************************************************
* Path Manipulation Routines.
********************************************************************/

/*
* These functions manipulate paths in "path_t" structures.
* 
* They eliminate multiple slashes in paths when they notice them, and keep
* the path non-slash terminated.
*
* Both path_set() and path_append() return 0 if the requested name
* would be too long.
*/

#define STRIP_TRAILING_SLASH(p) { \
       while ((p)->p_end > (p)->p_path && (p)->p_end[-1] == '/') \
               *--(p)->p_end = 0; \
       }

/*
* Move specified string into path.  Convert "" to "." to handle BSD
* semantics for a null path.  Strip trailing slashes.
*/
path_set(p, string)
       register path_t *p;
       char *string;
{
       if (strlen(string) > MAXPATHLEN) {
               (void)fprintf(stderr, "cp: %s: name too long.\n", string);
               exit_val = 1;
               return(0);
       }

       (void)strcpy(p->p_path, string);
       p->p_end = p->p_path + strlen(p->p_path);

       if (p->p_path == p->p_end) {
               *p->p_end++ = '.';
               *p->p_end = 0;
       }

       STRIP_TRAILING_SLASH(p);
       return(1);
}

/*
* Append specified string to path, inserting '/' if necessary.  Return a
* pointer to the old end of path for restoration.
*/
char *
path_append(p, name, len)
       register path_t *p;
       char *name;
       int len;
{
       char *old;

       old = p->p_end;
       if (len == -1)
               len = strlen(name);

       /*
        * The final "+ 1" accounts for the '/' between old path and name.
        */
       if ((len + p->p_end - p->p_path + 1) > MAXPATHLEN) {
               (void)fprintf(stderr,
                   "cp: %s/%s: name too long.\n", p->p_path, name);
               exit_val = 1;
               return(0);
       }

       /*
        * This code should always be executed, since paths shouldn't
        * end in '/'.
        */
       if (p->p_end[-1] != '/') {
               *p->p_end++ = '/';
               *p->p_end = 0;
       }

       (void)strncat(p->p_end, name, len);
       p->p_end += len;
       *p->p_end = 0;

       STRIP_TRAILING_SLASH(p);
       return(old);
}

/*
* Restore path to previous value.  (As returned by path_append.)
*/
void
path_restore(p, old)
       path_t *p;
       char *old;
{
       p->p_end = old;
       *p->p_end = 0;
}

/*
* Return basename of path.  (Like basename(1).)
*/
char *
path_basename(p)
       path_t *p;
{
       char *basename;

       basename = rindex(p->p_path, '/');
       return(basename ? ++basename : p->p_path);
}

usage()
{
       (void)fprintf(stderr,
          "usage: cp [-ip] f1 f2; or: cp [-irp] f1 ... fn directory\n");
       exit(1);
}