LPdir_unix.c revision 306195 
1/*
2 * Copyright (c) 2004, Richard Levitte <richard@levitte.org>
3 * 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 *
14 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
15 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
16 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
17 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
18 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
19 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
20 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
24 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25 */
26
27#include <stddef.h>
28#include <stdlib.h>
29#include <limits.h>
30#include <string.h>
31#include <sys/types.h>
32#include <dirent.h>
33#include <errno.h>
34#ifndef LPDIR_H
35# include "LPdir.h"
36#endif
37
38/*
39 * The POSIXly macro for the maximum number of characters in a file path is
40 * NAME_MAX.  However, some operating systems use PATH_MAX instead.
41 * Therefore, it seems natural to first check for PATH_MAX and use that, and
42 * if it doesn't exist, use NAME_MAX.
43 */
44#if defined(PATH_MAX)
45# define LP_ENTRY_SIZE PATH_MAX
46#elif defined(NAME_MAX)
47# define LP_ENTRY_SIZE NAME_MAX
48#endif
49
50/*
51 * Of course, there's the possibility that neither PATH_MAX nor NAME_MAX
52 * exist.  It's also possible that NAME_MAX exists but is define to a very
53 * small value (HP-UX offers 14), so we need to check if we got a result, and
54 * if it meets a minimum standard, and create or change it if not.
55 */
56#if !defined(LP_ENTRY_SIZE) || LP_ENTRY_SIZE<255
57# undef LP_ENTRY_SIZE
58# define LP_ENTRY_SIZE 255
59#endif
60
61struct LP_dir_context_st {
62    DIR *dir;
63    char entry_name[LP_ENTRY_SIZE + 1];
64};
65
66const char *LP_find_file(LP_DIR_CTX **ctx, const char *directory)
67{
68    struct dirent *direntry = NULL;
69
70    if (ctx == NULL || directory == NULL) {
71        errno = EINVAL;
72        return 0;
73    }
74
75    errno = 0;
76    if (*ctx == NULL) {
77        *ctx = (LP_DIR_CTX *)malloc(sizeof(LP_DIR_CTX));
78        if (*ctx == NULL) {
79            errno = ENOMEM;
80            return 0;
81        }
82        memset(*ctx, '\0', sizeof(LP_DIR_CTX));
83
84        (*ctx)->dir = opendir(directory);
85        if ((*ctx)->dir == NULL) {
86            int save_errno = errno; /* Probably not needed, but I'm paranoid */
87            free(*ctx);
88            *ctx = NULL;
89            errno = save_errno;
90            return 0;
91        }
92    }
93
94    direntry = readdir((*ctx)->dir);
95    if (direntry == NULL) {
96        return 0;
97    }
98
99    strncpy((*ctx)->entry_name, direntry->d_name,
100            sizeof((*ctx)->entry_name) - 1);
101    (*ctx)->entry_name[sizeof((*ctx)->entry_name) - 1] = '\0';
102    return (*ctx)->entry_name;
103}
104
105int LP_find_file_end(LP_DIR_CTX **ctx)
106{
107    if (ctx != NULL && *ctx != NULL) {
108        int ret = closedir((*ctx)->dir);
109
110        free(*ctx);
111        switch (ret) {
112        case 0:
113            return 1;
114        case -1:
115            return 0;
116        default:
117            break;
118        }
119    }
120    errno = EINVAL;
121    return 0;
122}
123