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scandir.c revision 1.5.4.1 
      1 /*
      2  * Copyright (c) 1983, 1993
      3  *	The Regents of the University of California.  All rights reserved.
      4  *
      5  * Redistribution and use in source and binary forms, with or without
      6  * modification, are permitted provided that the following conditions
      7  * are met:
      8  * 1. Redistributions of source code must retain the above copyright
      9  *    notice, this list of conditions and the following disclaimer.
     10  * 2. Redistributions in binary form must reproduce the above copyright
     11  *    notice, this list of conditions and the following disclaimer in the
     12  *    documentation and/or other materials provided with the distribution.
     13  * 3. All advertising materials mentioning features or use of this software
     14  *    must display the following acknowledgement:
     15  *	This product includes software developed by the University of
     16  *	California, Berkeley and its contributors.
     17  * 4. Neither the name of the University nor the names of its contributors
     18  *    may be used to endorse or promote products derived from this software
     19  *    without specific prior written permission.
     20  *
     21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     31  * SUCH DAMAGE.
     32  */
     33 
     34 #if defined(LIBC_SCCS) && !defined(lint)
     35 /*static char sccsid[] = "from: @(#)scandir.c	8.3 (Berkeley) 1/2/94";*/
     36 static char rcsid[] = "$Id: scandir.c,v 1.5.4.1 1995/04/26 01:01:16 jtc Exp $";
     37 #endif /* LIBC_SCCS and not lint */
     38 
     39 /*
     40  * Scan the directory dirname calling select to make a list of selected
     41  * directory entries then sort using qsort and compare routine dcomp.
     42  * Returns the number of entries and a pointer to a list of pointers to
     43  * struct dirent (through namelist). Returns -1 if there were any errors.
     44  */
     45 
     46 #include "namespace.h"
     47 #include <sys/types.h>
     48 #include <sys/stat.h>
     49 #include <dirent.h>
     50 #include <stdlib.h>
     51 #include <string.h>
     52 
     53 /*
     54  * The DIRSIZ macro is the minimum record length which will hold the directory
     55  * entry.  This requires the amount of space in struct dirent without the
     56  * d_name field, plus enough space for the name and a terminating nul byte
     57  * (dp->d_namlen + 1), rounded up to a 4 byte boundary.
     58  */
     59 #undef DIRSIZ
     60 #define DIRSIZ(dp)							\
     61 	((sizeof(struct dirent) - sizeof(dp)->d_name) +			\
     62 	    (((dp)->d_namlen + 1 + 3) &~ 3))
     63 
     64 int
     65 scandir(dirname, namelist, select, dcomp)
     66 	const char *dirname;
     67 	struct dirent ***namelist;
     68 	int (*select) __P((struct dirent *));
     69 	int (*dcomp) __P((const void *, const void *));
     70 {
     71 	register struct dirent *d, *p, **names;
     72 	register size_t nitems;
     73 	struct stat stb;
     74 	long arraysz;
     75 	DIR *dirp;
     76 
     77 	if ((dirp = opendir(dirname)) == NULL)
     78 		return(-1);
     79 	if (fstat(dirp->dd_fd, &stb) < 0)
     80 		return(-1);
     81 
     82 	/*
     83 	 * estimate the array size by taking the size of the directory file
     84 	 * and dividing it by a multiple of the minimum size entry.
     85 	 */
     86 	arraysz = (stb.st_size / 24);
     87 	names = (struct dirent **)malloc(arraysz * sizeof(struct dirent *));
     88 	if (names == NULL)
     89 		return(-1);
     90 
     91 	nitems = 0;
     92 	while ((d = readdir(dirp)) != NULL) {
     93 		if (select != NULL && !(*select)(d))
     94 			continue;	/* just selected names */
     95 		/*
     96 		 * Make a minimum size copy of the data
     97 		 */
     98 		p = (struct dirent *)malloc(DIRSIZ(d));
     99 		if (p == NULL)
    100 			return(-1);
    101 		p->d_ino = d->d_ino;
    102 		p->d_reclen = d->d_reclen;
    103 		p->d_namlen = d->d_namlen;
    104 		bcopy(d->d_name, p->d_name, p->d_namlen + 1);
    105 		/*
    106 		 * Check to make sure the array has space left and
    107 		 * realloc the maximum size.
    108 		 */
    109 		if (++nitems >= arraysz) {
    110 			if (fstat(dirp->dd_fd, &stb) < 0)
    111 				return(-1);	/* just might have grown */
    112 			arraysz = stb.st_size / 12;
    113 			names = (struct dirent **)realloc((char *)names,
    114 				arraysz * sizeof(struct dirent *));
    115 			if (names == NULL)
    116 				return(-1);
    117 		}
    118 		names[nitems-1] = p;
    119 	}
    120 	closedir(dirp);
    121 	if (nitems && dcomp != NULL)
    122 		qsort(names, nitems, sizeof(struct dirent *), dcomp);
    123 	*namelist = names;
    124 	return(nitems);
    125 }
    126 
    127 /*
    128  * Alphabetic order comparison routine for those who want it.
    129  */
    130 int
    131 alphasort(d1, d2)
    132 	const void *d1;
    133 	const void *d2;
    134 {
    135 	return(strcmp((*(struct dirent **)d1)->d_name,
    136 	    (*(struct dirent **)d2)->d_name));
    137 }
    138