dir.c

早期freebsd实现

    dp = value(cp);
    if ((dp[0] == '/' || dp[0] == '.') && chdir(short2str(dp)) >= 0) {
	xfree((ptr_t) cp);
	cp = Strsave(dp);
	printd = 1;
	return dgoto(cp);
    }
    (void) strcpy(ebuf, short2str(cp));
    xfree((ptr_t) cp);
    stderror(ERR_SYSTEM, ebuf, strerror(serrno));
    return (NULL);
}


/*
 * dopushd - push new directory onto directory stack.
 *	with no arguments exchange top and second.
 *	with numeric argument (+n) bring it to top.
 */
void
/*ARGSUSED*/
dopushd(v, t)
    Char **v;
    struct command *t;
{
    register struct directory *dp;

    skipargs(&v, " [<dir>|+<n>]");
    printd = 1;
    if (*v == NULL) {
	char   *tmp;

	if ((dp = dcwd->di_prev) == &dhead)
	    dp = dhead.di_prev;
	if (dp == dcwd)
	    stderror(ERR_NAME | ERR_NODIR);
	if (chdir(tmp = short2str(dp->di_name)) < 0)
	    stderror(ERR_SYSTEM, tmp, strerror(errno));
	dp->di_prev->di_next = dp->di_next;
	dp->di_next->di_prev = dp->di_prev;
	dp->di_next = dcwd->di_next;
	dp->di_prev = dcwd;
	dcwd->di_next->di_prev = dp;
	dcwd->di_next = dp;
    }
    else if (v[1] != NULL) {
	stderror(ERR_NAME | ERR_TOOMANY);
	/* NOTREACHED */
	return;
    }
    else if ((dp = dfind(*v)) != NULL) {
	char   *tmp;

	if (chdir(tmp = short2str(dp->di_name)) < 0)
	    stderror(ERR_SYSTEM, tmp, strerror(errno));
    }
    else {
	register Char *ccp;

	ccp = dfollow(*v);
	dp = (struct directory *) xcalloc(sizeof(struct directory), 1);
	dp->di_name = ccp;
	dp->di_count = 0;
	dp->di_prev = dcwd;
	dp->di_next = dcwd->di_next;
	dcwd->di_next = dp;
	dp->di_next->di_prev = dp;
    }
    dnewcwd(dp);
}

/*
 * dfind - find a directory if specified by numeric (+n) argument
 */
static struct directory *
dfind(cp)
    register Char *cp;
{
    register struct directory *dp;
    register int i;
    register Char *ep;

    if (*cp++ != '+')
	return (0);
    for (ep = cp; Isdigit(*ep); ep++)
	continue;
    if (*ep)
	return (0);
    i = getn(cp);
    if (i <= 0)
	return (0);
    for (dp = dcwd; i != 0; i--) {
	if ((dp = dp->di_prev) == &dhead)
	    dp = dp->di_prev;
	if (dp == dcwd)
	    stderror(ERR_NAME | ERR_DEEP);
    }
    return (dp);
}

/*
 * dopopd - pop a directory out of the directory stack
 *	with a numeric argument just discard it.
 */
void
/*ARGSUSED*/
dopopd(v, t)
    Char **v;
    struct command *t;
{
    register struct directory *dp, *p = NULL;

    skipargs(&v, " [+<n>]");
    printd = 1;
    if (*v == NULL)
	dp = dcwd;
    else if (v[1] != NULL) {
	stderror(ERR_NAME | ERR_TOOMANY);
	/* NOTREACHED */
	return;
    }
    else if ((dp = dfind(*v)) == 0)
	stderror(ERR_NAME | ERR_BADDIR);
    if (dp->di_prev == &dhead && dp->di_next == &dhead)
	stderror(ERR_NAME | ERR_EMPTY);
    if (dp == dcwd) {
	char   *tmp;

	if ((p = dp->di_prev) == &dhead)
	    p = dhead.di_prev;
	if (chdir(tmp = short2str(p->di_name)) < 0)
	    stderror(ERR_SYSTEM, tmp, strerror(errno));
    }
    dp->di_prev->di_next = dp->di_next;
    dp->di_next->di_prev = dp->di_prev;
    if (dp == dcwd)
	dnewcwd(p);
    else {
	printdirs();
    }
    dfree(dp);
}

/*
 * dfree - free the directory (or keep it if it still has ref count)
 */
void
dfree(dp)
    register struct directory *dp;
{

    if (dp->di_count != 0) {
	dp->di_next = dp->di_prev = 0;
    }
    else {
	xfree((char *) dp->di_name);
	xfree((ptr_t) dp);
    }
}

/*
 * dcanon - canonicalize the pathname, removing excess ./ and ../ etc.
 *	we are of course assuming that the file system is standardly
 *	constructed (always have ..'s, directories have links)
 */
Char   *
dcanon(cp, p)
    register Char *cp, *p;
{
    register Char *sp;
    register Char *p1, *p2;	/* general purpose */
    bool    slash;

    Char    link[MAXPATHLEN];
    char    tlink[MAXPATHLEN];
    int     cc;
    Char   *newcp;

    /*
     * christos: if the path given does not start with a slash prepend cwd. If
     * cwd does not start with a path or the result would be too long abort().
     */
    if (*cp != '/') {
	Char    tmpdir[MAXPATHLEN];

	p1 = value(STRcwd);
	if (p1 == NULL || *p1 != '/')
	    abort();
	if (Strlen(p1) + Strlen(cp) + 1 >= MAXPATHLEN)
	    abort();
	(void) Strcpy(tmpdir, p1);
	(void) Strcat(tmpdir, STRslash);
	(void) Strcat(tmpdir, cp);
	xfree((ptr_t) cp);
	cp = p = Strsave(tmpdir);
    }

    while (*p) {		/* for each component */
	sp = p;			/* save slash address */
	while (*++p == '/')	/* flush extra slashes */
	    continue;
	if (p != ++sp)
	    for (p1 = sp, p2 = p; (*p1++ = *p2++) != '\0';)
		continue;
	p = sp;			/* save start of component */
	slash = 0;
	while (*++p)		/* find next slash or end of path */
	    if (*p == '/') {
		slash = 1;
		*p = 0;
		break;
	    }

	if (*sp == '\0')	/* if component is null */
	    if (--sp == cp)	/* if path is one char (i.e. /) */
		break;
	    else
		*sp = '\0';
	else if (sp[0] == '.' && sp[1] == 0) {
	    if (slash) {
		for (p1 = sp, p2 = p + 1; (*p1++ = *p2++) != '\0';)
		    continue;
		p = --sp;
	    }
	    else if (--sp != cp)
		*sp = '\0';
	}
	else if (sp[0] == '.' && sp[1] == '.' && sp[2] == 0) {
	    /*
	     * We have something like "yyy/xxx/..", where "yyy" can be null or
	     * a path starting at /, and "xxx" is a single component. Before
	     * compressing "xxx/..", we want to expand "yyy/xxx", if it is a
	     * symbolic link.
	     */
	    *--sp = 0;		/* form the pathname for readlink */
	    if (sp != cp && !adrof(STRignore_symlinks) &&
		(cc = readlink(short2str(cp), tlink,
			       sizeof tlink)) >= 0) {
		(void) Strcpy(link, str2short(tlink));
		link[cc] = '\0';

		if (slash)
		    *p = '/';
		/*
		 * Point p to the '/' in "/..", and restore the '/'.
		 */
		*(p = sp) = '/';
		/*
		 * find length of p
		 */
		for (p1 = p; *p1++;)
		    continue;
		if (*link != '/') {
		    /*
		     * Relative path, expand it between the "yyy/" and the
		     * "/..". First, back sp up to the character past "yyy/".
		     */
		    while (*--sp != '/')
			continue;
		    sp++;
		    *sp = 0;
		    /*
		     * New length is "yyy/" + link + "/.." and rest
		     */
		    p1 = newcp = (Char *) xmalloc((size_t)
						(((sp - cp) + cc + (p1 - p)) *
						 sizeof(Char)));
		    /*
		     * Copy new path into newcp
		     */
		    for (p2 = cp; (*p1++ = *p2++) != '\0';)
			continue;
		    for (p1--, p2 = link; (*p1++ = *p2++) != '\0';)
			continue;
		    for (p1--, p2 = p; (*p1++ = *p2++) != '\0';)
			continue;
		    /*
		     * Restart canonicalization at expanded "/xxx".
		     */
		    p = sp - cp - 1 + newcp;
		}
		else {
		    /*
		     * New length is link + "/.." and rest
		     */
		    p1 = newcp = (Char *) xmalloc((size_t)
					    ((cc + (p1 - p)) * sizeof(Char)));
		    /*
		     * Copy new path into newcp
		     */
		    for (p2 = link; (*p1++ = *p2++) != '\0';)
			continue;
		    for (p1--, p2 = p; (*p1++ = *p2++) != '\0';)
			continue;
		    /*
		     * Restart canonicalization at beginning
		     */
		    p = newcp;
		}
		xfree((ptr_t) cp);
		cp = newcp;
		continue;	/* canonicalize the link */
	    }
	    *sp = '/';
	    if (sp != cp)
		while (*--sp != '/')
		    continue;
	    if (slash) {
		for (p1 = sp + 1, p2 = p + 1; (*p1++ = *p2++) != '\0';)
		    continue;
		p = sp;
	    }
	    else if (cp == sp)
		*++sp = '\0';
	    else
		*sp = '\0';
	}
	else {			/* normal dir name (not . or .. or nothing) */

	    if (sp != cp && adrof(STRchase_symlinks) &&
		!adrof(STRignore_symlinks) &&
		(cc = readlink(short2str(cp), tlink,
			       sizeof tlink)) >= 0) {
		(void) Strcpy(link, str2short(tlink));
		link[cc] = '\0';

		/*
		 * restore the '/'.
		 */
		if (slash)
		    *p = '/';

		/*
		 * point sp to p (rather than backing up).
		 */
		sp = p;

		/*
		 * find length of p
		 */
		for (p1 = p; *p1++;)
		    continue;
		if (*link != '/') {
		    /*
		     * Relative path, expand it between the "yyy/" and the
		     * remainder. First, back sp up to the character past
		     * "yyy/".
		     */
		    while (*--sp != '/')
			continue;
		    sp++;
		    *sp = 0;
		    /*
		     * New length is "yyy/" + link + "/.." and rest
		     */
		    p1 = newcp = (Char *) xmalloc((size_t)
						  (((sp - cp) + cc + (p1 - p))
						   * sizeof(Char)));
		    /*
		     * Copy new path into newcp
		     */
		    for (p2 = cp; (*p1++ = *p2++) != '\0';)
			continue;
		    for (p1--, p2 = link; (*p1++ = *p2++) != '\0';)
			continue;
		    for (p1--, p2 = p; (*p1++ = *p2++) != '\0';)
			continue;
		    /*
		     * Restart canonicalization at expanded "/xxx".
		     */
		    p = sp - cp - 1 + newcp;
		}
		else {
		    /*
		     * New length is link + the rest
		     */
		    p1 = newcp = (Char *) xmalloc((size_t)
					    ((cc + (p1 - p)) * sizeof(Char)));
		    /*
		     * Copy new path into newcp
		     */
		    for (p2 = link; (*p1++ = *p2++) != '\0';)
			continue;
		    for (p1--, p2 = p; (*p1++ = *p2++) != '\0';)
			continue;
		    /*
		     * Restart canonicalization at beginning
		     */
		    p = newcp;
		}
		xfree((ptr_t) cp);
		cp = newcp;
		continue;	/* canonicalize the link */
	    }
	    if (slash)
		*p = '/';
	}
    }

    /*
     * fix home...
     */
    p1 = value(STRhome);
    cc = Strlen(p1);
    /*
     * See if we're not in a subdir of STRhome
     */
    if (p1 && *p1 == '/' &&
	(Strncmp(p1, cp, cc) != 0 || (cp[cc] != '/' && cp[cc] != '\0'))) {
	static ino_t home_ino = -1;
	static dev_t home_dev = -1;
	static Char *home_ptr = NULL;
	struct stat statbuf;

	/*
	 * Get dev and ino of STRhome
	 */
	if (home_ptr != p1 &&
	    stat(short2str(p1), &statbuf) != -1) {
	    home_dev = statbuf.st_dev;
	    home_ino = statbuf.st_ino;
	    home_ptr = p1;
	}
	/*
	 * Start comparing dev & ino backwards
	 */
	p2 = Strcpy(link, cp);
	for (sp = NULL; *p2 && stat(short2str(p2), &statbuf) != -1;) {
	    if (statbuf.st_dev == home_dev &&
		statbuf.st_ino == home_ino) {
		sp = (Char *) - 1;
		break;
	    }
	    if ((sp = Strrchr(p2, '/')) != NULL)
		*sp = '\0';
	}
	/*
	 * See if we found it
	 */
	if (*p2 && sp == (Char *) -1) {
	    /*
	     * Use STRhome to make '~' work
	     */
	    newcp = Strspl(p1, cp + Strlen(p2));
	    xfree((ptr_t) cp);
	    cp = newcp;
	}
    }
    return cp;
}


/*
 * dnewcwd - make a new directory in the loop the current one
 */
static void
dnewcwd(dp)
    register struct directory *dp;
{
    dcwd = dp;
    dset(dcwd->di_name);
    if (printd && !(adrof(STRpushdsilent)))
	printdirs();
}