Usenet 1994 October/usenetsourcesnewsgroupsinfomagicoctober1994disk2.iso/std_unix/pax/2/pathname.c

C/C++ Source or Header | 1989-01-07 | 5KB | 234 lines

/* $Source: /u/mark/src/pax/RCS/pathname.c,v $
 *
 * $Revision: 1.1 $
 *
 * pathname.c - directory/pathname support functions
 *
 * DESCRIPTION
 *
 *    These functions provide directory/pathname support for PAX
 *
 * AUTHOR
 *
 *    Mark H. Colburn, NAPS International ([e-mail])
 *
 * Sponsored by The USENIX Association for public distribution.
 *
 * Copyright (c) 1989 Mark H. Colburn.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms are permitted
 * provided that the above copyright notice is 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 Mark H. Colburn and sponsored by The
 * USENIX Association.
 *
 * 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.
 *
 * $Log:    pathname.c,v $
 * Revision 1.1  88/12/23  18:02:21  mark
 * Initial revision
 *
 */

#ifndef lint
static char *ident = "$Id: pathname.c,v 1.1 88/12/23 18:02:21 mark Rel $";
static char *copyright = "Copyright (c) 1989 Mark H. Colburn.\nAll rights reserved.\n";
#endif /* ! lint */


/* Headers */

#include "pax.h"


/* dirneed  - checks for the existance of directories and possibly create
 *
 * DESCRIPTION
 *
 *    Dirneed checks to see if a directory of the name pointed to by name
 *    exists.  If the directory does exist, then dirneed returns 0.  If
 *    the directory does not exist and the f_create_dirs flag is set,
 *    then dirneed will create the needed directory, recursively creating
 *    any needed intermediate directory.
 *
 *    If f_create_dirs is not set, then no directories will be created
 *    and a value of -1 will be returned if the directory does not
 *    exist.
 *
 * PARAMETERS
 *
 *    name        - name of the directory to create
 *
 * RETURNS
 *
 *    Returns a 0 if the creation of the directory succeeded or if the
 *    directory already existed.  If the f_create_dirs flag was not set
 *    and the named directory does not exist, or the directory creation
 *    failed, a -1 will be returned to the calling routine.
 */

#ifdef __STDC__

int dirneed(char *name)

#else

int dirneed(name)
char           *name;

#endif
{
    char           *cp;
    char           *last;
    int             ok;
    static Stat     sb;

    last = NULL;
    for (cp = name; *cp;) {
    if (*cp++ == '/') {
        last = cp;
    }
    }
    if (last == NULL) {
    return (STAT(".", &sb));
    }
    *--last = '\0';
    ok = STAT(*name ? name : ".", &sb) == 0
    ? ((sb.sb_mode & S_IFMT) == S_IFDIR)
    : (f_create_dirs && dirneed(name) == 0 && dirmake(name, &sb) == 0);
    *last = '/';
    return (ok ? 0 : -1);
}


/* nameopt - optimize a pathname
 *
 * DESCRIPTION
 *
 *     Confused by "<symlink>/.." twistiness. Returns the number of final
 *     pathname elements (zero for "/" or ".") or -1 if unsuccessful.
 *
 * PARAMETERS
 *
 *    char    *begin    - name of the path to optimize
 *
 * RETURNS
 *
 *    Returns 0 if successful, non-zero otherwise.
 *
 */

#ifdef __STDC__

int nameopt(char *begin)

#else

int nameopt(begin)
char           *begin;

#endif
{
    char           *name;
    char           *item;
    int             idx;
    int             absolute;
    char           *element[PATHELEM];

    absolute = (*(name = begin) == '/');
    idx = 0;
    for (;;) {
    if (idx == PATHELEM) {
        warn(begin, "Too many elements");
        return (-1);
    }
    while (*name == '/') {
        ++name;
    }
    if (*name == '\0') {
        break;
    }
    element[idx] = item = name;
    while (*name && *name != '/') {
        ++name;
    }
    if (*name) {
        *name++ = '\0';
    }
    if (strcmp(item, "..") == 0) {
        if (idx == 0) {
        if (!absolute) {
            ++idx;
        }
        } else if (strcmp(element[idx - 1], "..") == 0) {
        ++idx;
        } else {
        --idx;
        }
    } else if (strcmp(item, ".") != 0) {
        ++idx;
    }
    }
    if (idx == 0) {
    element[idx++] = absolute ? "" : ".";
    }
    element[idx] = NULL;
    name = begin;
    if (absolute) {
    *name++ = '/';
    }
    for (idx = 0; item = element[idx]; ++idx, *name++ = '/') {
    while (*item) {
        *name++ = *item++;
    }
    }
    *--name = '\0';
    return (idx);
}


/* dirmake - make a directory
 *
 * DESCRIPTION
 *
 *    Dirmake makes a directory with the appropritate permissions.
 *
 * PARAMETERS
 *
 *    char     *name    - Name of directory make
 *    Stat    *asb    - Stat structure of directory to make
 *
 * RETURNS
 *
 *     Returns zero if successful, -1 otherwise.
 *
 */

#ifdef __STDC__

int dirmake(char *name, Stat *asb)

#else

int dirmake(name, asb)
char           *name;
Stat           *asb;

#endif
{
    if (mkdir(name, (int) (asb->sb_mode & S_IPOPN)) < 0) {
    return (-1);
    }
    if (asb->sb_mode & S_IPEXE) {
    chmod(name, (int) (asb->sb_mode & S_IPERM));
    }
    if (f_owner) {
    chown(name, (int) asb->sb_uid, (int) asb->sb_gid);
    }
    return (0);
}