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scandir.c revision 1.7 
      1 /*	$NetBSD: scandir.c,v 1.7 1997/07/13 19:46:13 christos Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 1983, 1993
      5  *	The Regents of the University of California.  All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  * 3. All advertising materials mentioning features or use of this software
     16  *    must display the following acknowledgement:
     17  *	This product includes software developed by the University of
     18  *	California, Berkeley and its contributors.
     19  * 4. Neither the name of the University nor the names of its contributors
     20  *    may be used to endorse or promote products derived from this software
     21  *    without specific prior written permission.
     22  *
     23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     33  * SUCH DAMAGE.
     34  */
     35 
     36 #include <sys/cdefs.h>
     37 #if defined(LIBC_SCCS) && !defined(lint)
     38 #if 0
     39 static char sccsid[] = "@(#)scandir.c	8.3 (Berkeley) 1/2/94";
     40 #else
     41 __RCSID("$NetBSD: scandir.c,v 1.7 1997/07/13 19:46:13 christos Exp $");
     42 #endif
     43 #endif /* LIBC_SCCS and not lint */
     44 
     45 /*
     46  * Scan the directory dirname calling select to make a list of selected
     47  * directory entries then sort using qsort and compare routine dcomp.
     48  * Returns the number of entries and a pointer to a list of pointers to
     49  * struct dirent (through namelist). Returns -1 if there were any errors.
     50  */
     51 
     52 #include <sys/types.h>
     53 #include <sys/stat.h>
     54 #include <dirent.h>
     55 #include <stdlib.h>
     56 #include <string.h>
     57 
     58 /*
     59  * The DIRSIZ macro is the minimum record length which will hold the directory
     60  * entry.  This requires the amount of space in struct dirent without the
     61  * d_name field, plus enough space for the name and a terminating nul byte
     62  * (dp->d_namlen + 1), rounded up to a 4 byte boundary.
     63  */
     64 #undef DIRSIZ
     65 #define DIRSIZ(dp)							\
     66 	((sizeof(struct dirent) - sizeof(dp)->d_name) +			\
     67 	    (((dp)->d_namlen + 1 + 3) &~ 3))
     68 
     69 int
     70 scandir(dirname, namelist, select, dcomp)
     71 	const char *dirname;
     72 	struct dirent ***namelist;
     73 	int (*select) __P((struct dirent *));
     74 	int (*dcomp) __P((const void *, const void *));
     75 {
     76 	register struct dirent *d, *p, **names;
     77 	register size_t nitems;
     78 	struct stat stb;
     79 	long arraysz;
     80 	DIR *dirp;
     81 
     82 	if ((dirp = opendir(dirname)) == NULL)
     83 		return(-1);
     84 	if (fstat(dirp->dd_fd, &stb) < 0)
     85 		return(-1);
     86 
     87 	/*
     88 	 * estimate the array size by taking the size of the directory file
     89 	 * and dividing it by a multiple of the minimum size entry.
     90 	 */
     91 	arraysz = (stb.st_size / 24);
     92 	names = (struct dirent **)malloc(arraysz * sizeof(struct dirent *));
     93 	if (names == NULL)
     94 		return(-1);
     95 
     96 	nitems = 0;
     97 	while ((d = readdir(dirp)) != NULL) {
     98 		if (select != NULL && !(*select)(d))
     99 			continue;	/* just selected names */
    100 		/*
    101 		 * Make a minimum size copy of the data
    102 		 */
    103 		p = (struct dirent *)malloc(DIRSIZ(d));
    104 		if (p == NULL)
    105 			return(-1);
    106 		p->d_ino = d->d_ino;
    107 		p->d_reclen = d->d_reclen;
    108 		p->d_namlen = d->d_namlen;
    109 		bcopy(d->d_name, p->d_name, p->d_namlen + 1);
    110 		/*
    111 		 * Check to make sure the array has space left and
    112 		 * realloc the maximum size.
    113 		 */
    114 		if (++nitems >= arraysz) {
    115 			if (fstat(dirp->dd_fd, &stb) < 0)
    116 				return(-1);	/* just might have grown */
    117 			arraysz = stb.st_size / 12;
    118 			names = (struct dirent **)realloc((char *)names,
    119 				arraysz * sizeof(struct dirent *));
    120 			if (names == NULL)
    121 				return(-1);
    122 		}
    123 		names[nitems-1] = p;
    124 	}
    125 	closedir(dirp);
    126 	if (nitems && dcomp != NULL)
    127 		qsort(names, nitems, sizeof(struct dirent *), dcomp);
    128 	*namelist = names;
    129 	return(nitems);
    130 }
    131 
    132 /*
    133  * Alphabetic order comparison routine for those who want it.
    134  */
    135 int
    136 alphasort(d1, d2)
    137 	const void *d1;
    138 	const void *d2;
    139 {
    140 	return(strcmp((*(struct dirent **)d1)->d_name,
    141 	    (*(struct dirent **)d2)->d_name));
    142 }
    143