LPdir_unix.c revision 296465 
1/*
2 * $LP: LPlib/source/LPdir_unix.c,v 1.11 2004/09/23 22:07:22 _cvs_levitte Exp
3 * $
4 */
5/*
6 * Copyright (c) 2004, Richard Levitte <richard@levitte.org>
7 * All rights reserved.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 *    notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 *    notice, this list of conditions and the following disclaimer in the
16 *    documentation and/or other materials provided with the distribution.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
19 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
20 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
21 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
22 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
23 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
24 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
25 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
26 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
28 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29 */
30
31#include <stddef.h>
32#include <stdlib.h>
33#include <limits.h>
34#include <string.h>
35#include <sys/types.h>
36#include <dirent.h>
37#include <errno.h>
38#ifndef LPDIR_H
39# include "LPdir.h"
40#endif
41
42/*
43 * The POSIXly macro for the maximum number of characters in a file path is
44 * NAME_MAX.  However, some operating systems use PATH_MAX instead.
45 * Therefore, it seems natural to first check for PATH_MAX and use that, and
46 * if it doesn't exist, use NAME_MAX.
47 */
48#if defined(PATH_MAX)
49# define LP_ENTRY_SIZE PATH_MAX
50#elif defined(NAME_MAX)
51# define LP_ENTRY_SIZE NAME_MAX
52#endif
53
54/*
55 * Of course, there's the possibility that neither PATH_MAX nor NAME_MAX
56 * exist.  It's also possible that NAME_MAX exists but is define to a very
57 * small value (HP-UX offers 14), so we need to check if we got a result, and
58 * if it meets a minimum standard, and create or change it if not.
59 */
60#if !defined(LP_ENTRY_SIZE) || LP_ENTRY_SIZE<255
61# undef LP_ENTRY_SIZE
62# define LP_ENTRY_SIZE 255
63#endif
64
65struct LP_dir_context_st {
66    DIR *dir;
67    char entry_name[LP_ENTRY_SIZE + 1];
68};
69
70const char *LP_find_file(LP_DIR_CTX **ctx, const char *directory)
71{
72    struct dirent *direntry = NULL;
73
74    if (ctx == NULL || directory == NULL) {
75        errno = EINVAL;
76        return 0;
77    }
78
79    errno = 0;
80    if (*ctx == NULL) {
81        *ctx = (LP_DIR_CTX *)malloc(sizeof(LP_DIR_CTX));
82        if (*ctx == NULL) {
83            errno = ENOMEM;
84            return 0;
85        }
86        memset(*ctx, '\0', sizeof(LP_DIR_CTX));
87
88        (*ctx)->dir = opendir(directory);
89        if ((*ctx)->dir == NULL) {
90            int save_errno = errno; /* Probably not needed, but I'm paranoid */
91            free(*ctx);
92            *ctx = NULL;
93            errno = save_errno;
94            return 0;
95        }
96    }
97
98    direntry = readdir((*ctx)->dir);
99    if (direntry == NULL) {
100        return 0;
101    }
102
103    strncpy((*ctx)->entry_name, direntry->d_name,
104            sizeof((*ctx)->entry_name) - 1);
105    (*ctx)->entry_name[sizeof((*ctx)->entry_name) - 1] = '\0';
106    return (*ctx)->entry_name;
107}
108
109int LP_find_file_end(LP_DIR_CTX **ctx)
110{
111    if (ctx != NULL && *ctx != NULL) {
112        int ret = closedir((*ctx)->dir);
113
114        free(*ctx);
115        switch (ret) {
116        case 0:
117            return 1;
118        case -1:
119            return 0;
120        default:
121            break;
122        }
123    }
124    errno = EINVAL;
125    return 0;
126}
127