1 /* $LP: LPlib/source/LPdir_unix.c,v 1.11 2004/09/23 22:07:22 _cvs_levitte Exp $ */
2 /*
3  * Copyright (c) 2004, Richard Levitte <richard@levitte.org>
4  * All rights reserved.
5  *
6  * Redistribution and use in source and binary forms, with or without
7  * modification, are permitted provided that the following conditions
8  * are met:
9  * 1. Redistributions of source code must retain the above copyright
10  *    notice, this list of conditions and the following disclaimer.
11  * 2. Redistributions in binary form must reproduce the above copyright
12  *    notice, this list of conditions and the following disclaimer in the
13  *    documentation and/or other materials provided with the distribution.
14  *
15  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
16  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
17  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
18  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
19  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
20  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
21  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
22  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
23  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
24  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
25  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26  */
27 
28 #include <stddef.h>
29 #include <stdlib.h>
30 #include <limits.h>
31 #include <string.h>
32 #include <sys/types.h>
33 #include <dirent.h>
34 #include <errno.h>
35 #ifndef LPDIR_H
36 #include "LPdir.h"
37 #endif
38 
39 /* The POSIXly macro for the maximum number of characters in a file path
40    is NAME_MAX.  However, some operating systems use PATH_MAX instead.
41    Therefore, it seems natural to first check for PATH_MAX and use that,
42    and if it doesn't exist, use NAME_MAX. */
43 #if defined(PATH_MAX)
44 # define LP_ENTRY_SIZE PATH_MAX
45 #elif defined(NAME_MAX)
46 # define LP_ENTRY_SIZE NAME_MAX
47 #endif
48 
49 /* Of course, there's the possibility that neither PATH_MAX nor NAME_MAX
50    exist.  It's also possible that NAME_MAX exists but is define to a
51    very small value (HP-UX offers 14), so we need to check if we got a
52    result, and if it meets a minimum standard, and create or change it
53    if not. */
54 #if !defined(LP_ENTRY_SIZE) || LP_ENTRY_SIZE<255
55 # undef LP_ENTRY_SIZE
56 # define LP_ENTRY_SIZE 255
57 #endif
58 
59 struct LP_dir_context_st
60 {
61   DIR *dir;
62   char entry_name[LP_ENTRY_SIZE+1];
63 };
64 
65 const char *LP_find_file(LP_DIR_CTX **ctx, const char *directory)
66 {
67   struct dirent *direntry = NULL;
68 
69   if (ctx == NULL || directory == NULL)
70     {
71       errno = EINVAL;
72       return 0;
73     }
74 
75   errno = 0;
76   if (*ctx == NULL)
77     {
78       *ctx = (LP_DIR_CTX *)malloc(sizeof(LP_DIR_CTX));
79       if (*ctx == NULL)
80 	{
81 	  errno = ENOMEM;
82 	  return 0;
83 	}
84       memset(*ctx, '\0', sizeof(LP_DIR_CTX));
85 
86       (*ctx)->dir = opendir(directory);
87       if ((*ctx)->dir == NULL)
88 	{
89 	  int save_errno = errno; /* Probably not needed, but I'm paranoid */
90 	  free(*ctx);
91 	  *ctx = NULL;
92 	  errno = save_errno;
93 	  return 0;
94 	}
95     }
96 
97   direntry = readdir((*ctx)->dir);
98   if (direntry == NULL)
99     {
100       return 0;
101     }
102 
103   strncpy((*ctx)->entry_name, direntry->d_name, sizeof((*ctx)->entry_name) - 1);
104   (*ctx)->entry_name[sizeof((*ctx)->entry_name) - 1] = '\0';
105   return (*ctx)->entry_name;
106 }
107 
108 int LP_find_file_end(LP_DIR_CTX **ctx)
109 {
110   if (ctx != NULL && *ctx != NULL)
111     {
112       int ret = closedir((*ctx)->dir);
113 
114       free(*ctx);
115       switch (ret)
116 	{
117 	case 0:
118 	  return 1;
119 	case -1:
120 	  return 0;
121 	default:
122 	  break;
123 	}
124     }
125   errno = EINVAL;
126   return 0;
127 }
128