1 /*************************************************
2 * Exim - an Internet mail transport agent *
3 *************************************************/
4
5 /* Copyright (c) University of Cambridge 1995 - 2015 */
6 /* Copyright (c) The Exim Maintainers 2020 */
7 /* See the file NOTICE for conditions of use and distribution. */
8
9 /* The idea for this code came from Matthew Byng-Maddick, but his original has
10 been heavily reworked a lot for Exim 4 (and it now uses stat() (more precisely:
11 lstat()) rather than a directory scan). */
12
13
14 #include "../exim.h"
15 #include "lf_functions.h"
16
17
18
19 /*************************************************
20 * Open entry point *
21 *************************************************/
22
23 /* See local README for interface description. We open the directory to test
24 whether it exists and whether it is searchable. However, we don't need to keep
25 it open, because the "search" can be done by a call to lstat() rather than
26 actually scanning through the list of files. */
27
28 static void *
dsearch_open(const uschar * dirname,uschar ** errmsg)29 dsearch_open(const uschar * dirname, uschar ** errmsg)
30 {
31 DIR * dp = exim_opendir(dirname);
32 if (!dp)
33 {
34 *errmsg = string_open_failed("%s for directory search", dirname);
35 return NULL;
36 }
37 closedir(dp);
38 return (void *)(-1);
39 }
40
41
42 /*************************************************
43 * Check entry point *
44 *************************************************/
45
46 /* The handle will always be (void *)(-1), but don't try casting it to an
47 integer as this gives warnings on 64-bit systems. */
48
49 static BOOL
dsearch_check(void * handle,const uschar * filename,int modemask,uid_t * owners,gid_t * owngroups,uschar ** errmsg)50 dsearch_check(void * handle, const uschar * filename, int modemask,
51 uid_t * owners, gid_t * owngroups, uschar ** errmsg)
52 {
53 handle = handle;
54 if (*filename == '/')
55 return lf_check_file(-1, filename, S_IFDIR, modemask, owners, owngroups,
56 "dsearch", errmsg) == 0;
57 *errmsg = string_sprintf("dirname '%s' for dsearch is not absolute", filename);
58 return FALSE;
59 }
60
61
62 /*************************************************
63 * Find entry point *
64 *************************************************/
65
66 #define RET_FULL BIT(0)
67 #define FILTER_TYPE BIT(1)
68 #define FILTER_ALL BIT(1)
69 #define FILTER_FILE BIT(2)
70 #define FILTER_DIR BIT(3)
71 #define FILTER_SUBDIR BIT(4)
72
73 /* See local README for interface description. We use lstat() instead of
74 scanning the directory, as it is hopefully faster to let the OS do the scanning
75 for us. */
76
77 static int
dsearch_find(void * handle,const uschar * dirname,const uschar * keystring,int length,uschar ** result,uschar ** errmsg,uint * do_cache,const uschar * opts)78 dsearch_find(void * handle, const uschar * dirname, const uschar * keystring,
79 int length, uschar ** result, uschar ** errmsg, uint * do_cache,
80 const uschar * opts)
81 {
82 struct stat statbuf;
83 int save_errno;
84 uschar * filename;
85 unsigned flags = 0;
86
87 if (Ustrchr(keystring, '/') != 0)
88 {
89 *errmsg = string_sprintf("key for dsearch lookup contains a slash: %s",
90 keystring);
91 return DEFER;
92 }
93
94 if (opts)
95 {
96 int sep = ',';
97 uschar * ele;
98
99 while ((ele = string_nextinlist(&opts, &sep, NULL, 0)))
100 if (Ustrcmp(ele, "ret=full") == 0)
101 flags |= RET_FULL;
102 else if (Ustrncmp(ele, "filter=", 7) == 0)
103 {
104 ele += 7;
105 if (Ustrcmp(ele, "file") == 0)
106 flags |= FILTER_TYPE | FILTER_FILE;
107 else if (Ustrcmp(ele, "dir") == 0)
108 flags |= FILTER_TYPE | FILTER_DIR;
109 else if (Ustrcmp(ele, "subdir") == 0)
110 flags |= FILTER_TYPE | FILTER_SUBDIR; /* like dir but not "." or ".." */
111 }
112 }
113
114 filename = string_sprintf("%s/%s", dirname, keystring);
115 if ( Ulstat(filename, &statbuf) >= 0
116 && ( !(flags & FILTER_TYPE)
117 || (flags & FILTER_FILE && S_ISREG(statbuf.st_mode))
118 || ( flags & (FILTER_DIR | FILTER_SUBDIR)
119 && S_ISDIR(statbuf.st_mode)
120 && ( flags & FILTER_DIR
121 || keystring[0] != '.'
122 || keystring[1] && keystring[1] != '.'
123 ) ) ) )
124 {
125 /* Since the filename exists in the filesystem, we can return a
126 non-tainted result. */
127 *result = string_copy_taint(flags & RET_FULL ? filename : keystring, FALSE);
128 return OK;
129 }
130
131 if (errno == ENOENT || errno == 0) return FAIL;
132
133 save_errno = errno;
134 *errmsg = string_sprintf("%s: lstat: %s", filename, strerror(errno));
135 errno = save_errno;
136 return DEFER;
137 }
138
139
140 /*************************************************
141 * Close entry point *
142 *************************************************/
143
144 /* See local README for interface description */
145
146 void
dsearch_close(void * handle)147 static dsearch_close(void *handle)
148 {
149 handle = handle; /* Avoid compiler warning */
150 }
151
152
153 /*************************************************
154 * Version reporting entry point *
155 *************************************************/
156
157 /* See local README for interface description. */
158
159 #include "../version.h"
160
161 void
dsearch_version_report(FILE * f)162 dsearch_version_report(FILE *f)
163 {
164 #ifdef DYNLOOKUP
165 fprintf(f, "Library version: dsearch: Exim version %s\n", EXIM_VERSION_STR);
166 #endif
167 }
168
169
170 static lookup_info _lookup_info = {
171 .name = US"dsearch", /* lookup name */
172 .type = lookup_absfile, /* uses absolute file name */
173 .open = dsearch_open, /* open function */
174 .check = dsearch_check, /* check function */
175 .find = dsearch_find, /* find function */
176 .close = dsearch_close, /* close function */
177 .tidy = NULL, /* no tidy function */
178 .quote = NULL, /* no quoting function */
179 .version_report = dsearch_version_report /* version reporting */
180 };
181
182 #ifdef DYNLOOKUP
183 #define dsearch_lookup_module_info _lookup_module_info
184 #endif
185
186 static lookup_info *_lookup_list[] = { &_lookup_info };
187 lookup_module_info dsearch_lookup_module_info = { LOOKUP_MODULE_INFO_MAGIC, _lookup_list, 1 };
188
189 /* End of lookups/dsearch.c */
190