ngx_http_random_index_module.c revision e18a033b
1
2/*
3 * Copyright (C) Igor Sysoev
4 * Copyright (C) Nginx, Inc.
5 */
6
7
8#include <ngx_config.h>
9#include <ngx_core.h>
10#include <ngx_http.h>
11
12
13typedef struct {
14    ngx_flag_t  enable;
15} ngx_http_random_index_loc_conf_t;
16
17
18#define NGX_HTTP_RANDOM_INDEX_PREALLOCATE  50
19
20
21static ngx_int_t ngx_http_random_index_error(ngx_http_request_t *r,
22    ngx_dir_t *dir, ngx_str_t *name);
23static ngx_int_t ngx_http_random_index_init(ngx_conf_t *cf);
24static void *ngx_http_random_index_create_loc_conf(ngx_conf_t *cf);
25static char *ngx_http_random_index_merge_loc_conf(ngx_conf_t *cf,
26    void *parent, void *child);
27
28
29static ngx_command_t  ngx_http_random_index_commands[] = {
30
31    { ngx_string("random_index"),
32      NGX_HTTP_LOC_CONF|NGX_CONF_FLAG,
33      ngx_conf_set_flag_slot,
34      NGX_HTTP_LOC_CONF_OFFSET,
35      offsetof(ngx_http_random_index_loc_conf_t, enable),
36      NULL },
37
38      ngx_null_command
39};
40
41
42static ngx_http_module_t  ngx_http_random_index_module_ctx = {
43    NULL,                                  /* preconfiguration */
44    ngx_http_random_index_init,            /* postconfiguration */
45
46    NULL,                                  /* create main configuration */
47    NULL,                                  /* init main configuration */
48
49    NULL,                                  /* create server configuration */
50    NULL,                                  /* merge server configuration */
51
52    ngx_http_random_index_create_loc_conf, /* create location configuration */
53    ngx_http_random_index_merge_loc_conf   /* merge location configuration */
54};
55
56
57ngx_module_t  ngx_http_random_index_module = {
58    NGX_MODULE_V1,
59    &ngx_http_random_index_module_ctx,     /* module context */
60    ngx_http_random_index_commands,        /* module directives */
61    NGX_HTTP_MODULE,                       /* module type */
62    NULL,                                  /* init master */
63    NULL,                                  /* init module */
64    NULL,                                  /* init process */
65    NULL,                                  /* init thread */
66    NULL,                                  /* exit thread */
67    NULL,                                  /* exit process */
68    NULL,                                  /* exit master */
69    NGX_MODULE_V1_PADDING
70};
71
72
73static ngx_int_t
74ngx_http_random_index_handler(ngx_http_request_t *r)
75{
76    u_char                            *last, *filename;
77    size_t                             len, allocated, root;
78    ngx_err_t                          err;
79    ngx_int_t                          rc;
80    ngx_str_t                          path, uri, *name;
81    ngx_dir_t                          dir;
82    ngx_uint_t                         n, level;
83    ngx_array_t                        names;
84    ngx_http_random_index_loc_conf_t  *rlcf;
85
86    if (r->uri.data[r->uri.len - 1] != '/') {
87        return NGX_DECLINED;
88    }
89
90    if (!(r->method & (NGX_HTTP_GET|NGX_HTTP_HEAD|NGX_HTTP_POST))) {
91        return NGX_DECLINED;
92    }
93
94    rlcf = ngx_http_get_module_loc_conf(r, ngx_http_random_index_module);
95
96    if (!rlcf->enable) {
97        return NGX_DECLINED;
98    }
99
100#if (NGX_HAVE_D_TYPE)
101    len = NGX_DIR_MASK_LEN;
102#else
103    len = NGX_HTTP_RANDOM_INDEX_PREALLOCATE;
104#endif
105
106    last = ngx_http_map_uri_to_path(r, &path, &root, len);
107    if (last == NULL) {
108        return NGX_HTTP_INTERNAL_SERVER_ERROR;
109    }
110
111    allocated = path.len;
112
113    path.len = last - path.data - 1;
114    path.data[path.len] = '\0';
115
116    ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
117                   "http random index: \"%s\"", path.data);
118
119    if (ngx_open_dir(&path, &dir) == NGX_ERROR) {
120        err = ngx_errno;
121
122        if (err == NGX_ENOENT
123            || err == NGX_ENOTDIR
124            || err == NGX_ENAMETOOLONG)
125        {
126            level = NGX_LOG_ERR;
127            rc = NGX_HTTP_NOT_FOUND;
128
129        } else if (err == NGX_EACCES) {
130            level = NGX_LOG_ERR;
131            rc = NGX_HTTP_FORBIDDEN;
132
133        } else {
134            level = NGX_LOG_CRIT;
135            rc = NGX_HTTP_INTERNAL_SERVER_ERROR;
136        }
137
138        ngx_log_error(level, r->connection->log, err,
139                      ngx_open_dir_n " \"%s\" failed", path.data);
140
141        return rc;
142    }
143
144    if (ngx_array_init(&names, r->pool, 32, sizeof(ngx_str_t)) != NGX_OK) {
145        return ngx_http_random_index_error(r, &dir, &path);
146    }
147
148    filename = path.data;
149    filename[path.len] = '/';
150
151    for ( ;; ) {
152        ngx_set_errno(0);
153
154        if (ngx_read_dir(&dir) == NGX_ERROR) {
155            err = ngx_errno;
156
157            if (err != NGX_ENOMOREFILES) {
158                ngx_log_error(NGX_LOG_CRIT, r->connection->log, err,
159                              ngx_read_dir_n " \"%V\" failed", &path);
160                return ngx_http_random_index_error(r, &dir, &path);
161            }
162
163            break;
164        }
165
166        ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
167                       "http random index file: \"%s\"", ngx_de_name(&dir));
168
169        if (ngx_de_name(&dir)[0] == '.') {
170            continue;
171        }
172
173        len = ngx_de_namelen(&dir);
174
175        if (dir.type == 0 || ngx_de_is_link(&dir)) {
176
177            /* 1 byte for '/' and 1 byte for terminating '\0' */
178
179            if (path.len + 1 + len + 1 > allocated) {
180                allocated = path.len + 1 + len + 1
181                                     + NGX_HTTP_RANDOM_INDEX_PREALLOCATE;
182
183                filename = ngx_pnalloc(r->pool, allocated);
184                if (filename == NULL) {
185                    return ngx_http_random_index_error(r, &dir, &path);
186                }
187
188                last = ngx_cpystrn(filename, path.data, path.len + 1);
189                *last++ = '/';
190            }
191
192            ngx_cpystrn(last, ngx_de_name(&dir), len + 1);
193
194            if (ngx_de_info(filename, &dir) == NGX_FILE_ERROR) {
195                err = ngx_errno;
196
197                if (err != NGX_ENOENT) {
198                    ngx_log_error(NGX_LOG_CRIT, r->connection->log, err,
199                                  ngx_de_info_n " \"%s\" failed", filename);
200                    return ngx_http_random_index_error(r, &dir, &path);
201                }
202
203                if (ngx_de_link_info(filename, &dir) == NGX_FILE_ERROR) {
204                    ngx_log_error(NGX_LOG_CRIT, r->connection->log, ngx_errno,
205                                  ngx_de_link_info_n " \"%s\" failed",
206                                  filename);
207                    return ngx_http_random_index_error(r, &dir, &path);
208                }
209            }
210        }
211
212        if (!ngx_de_is_file(&dir)) {
213            continue;
214        }
215
216        name = ngx_array_push(&names);
217        if (name == NULL) {
218            return ngx_http_random_index_error(r, &dir, &path);
219        }
220
221        name->len = len;
222
223        name->data = ngx_pnalloc(r->pool, len);
224        if (name->data == NULL) {
225            return ngx_http_random_index_error(r, &dir, &path);
226        }
227
228        ngx_memcpy(name->data, ngx_de_name(&dir), len);
229    }
230
231    if (ngx_close_dir(&dir) == NGX_ERROR) {
232        ngx_log_error(NGX_LOG_ALERT, r->connection->log, ngx_errno,
233                      ngx_close_dir_n " \"%V\" failed", &path);
234    }
235
236    n = names.nelts;
237
238    if (n == 0) {
239        return NGX_DECLINED;
240    }
241
242    name = names.elts;
243
244    n = (ngx_uint_t) (((uint64_t) ngx_random() * n) / 0x80000000);
245
246    uri.len = r->uri.len + name[n].len;
247
248    uri.data = ngx_pnalloc(r->pool, uri.len);
249    if (uri.data == NULL) {
250        return NGX_HTTP_INTERNAL_SERVER_ERROR;
251    }
252
253    last = ngx_copy(uri.data, r->uri.data, r->uri.len);
254    ngx_memcpy(last, name[n].data, name[n].len);
255
256    return ngx_http_internal_redirect(r, &uri, &r->args);
257}
258
259
260static ngx_int_t
261ngx_http_random_index_error(ngx_http_request_t *r, ngx_dir_t *dir,
262    ngx_str_t *name)
263{
264    if (ngx_close_dir(dir) == NGX_ERROR) {
265        ngx_log_error(NGX_LOG_ALERT, r->connection->log, ngx_errno,
266                      ngx_close_dir_n " \"%V\" failed", name);
267    }
268
269    return NGX_HTTP_INTERNAL_SERVER_ERROR;
270}
271
272
273static void *
274ngx_http_random_index_create_loc_conf(ngx_conf_t *cf)
275{
276    ngx_http_random_index_loc_conf_t  *conf;
277
278    conf = ngx_palloc(cf->pool, sizeof(ngx_http_random_index_loc_conf_t));
279    if (conf == NULL) {
280        return NULL;
281    }
282
283    conf->enable = NGX_CONF_UNSET;
284
285    return conf;
286}
287
288
289static char *
290ngx_http_random_index_merge_loc_conf(ngx_conf_t *cf, void *parent, void *child)
291{
292    ngx_http_random_index_loc_conf_t *prev = parent;
293    ngx_http_random_index_loc_conf_t *conf = child;
294
295    ngx_conf_merge_value(conf->enable, prev->enable, 0);
296
297    return NGX_CONF_OK;
298}
299
300
301static ngx_int_t
302ngx_http_random_index_init(ngx_conf_t *cf)
303{
304    ngx_http_handler_pt        *h;
305    ngx_http_core_main_conf_t  *cmcf;
306
307    cmcf = ngx_http_conf_get_module_main_conf(cf, ngx_http_core_module);
308
309    h = ngx_array_push(&cmcf->phases[NGX_HTTP_CONTENT_PHASE].handlers);
310    if (h == NULL) {
311        return NGX_ERROR;
312    }
313
314    *h = ngx_http_random_index_handler;
315
316    return NGX_OK;
317}
318