handler.c

   1 /*
   2  * uhttpd - Tiny single-threaded httpd
   3  *
   4  *   Copyright (C) 2015 Felix Fietkau <nbd@openwrt.org>
   5  *
   6  * Permission to use, copy, modify, and/or distribute this software for any
   7  * purpose with or without fee is hereby granted, provided that the above
   8  * copyright notice and this permission notice appear in all copies.
   9  *
  10  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  11  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  12  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  13  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  14  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  15  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  16  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  17  */
  18
  19 #include <libubox/blobmsg.h>
  20 #include <libubox/blobmsg_json.h>
  21 #include <libubox/json_script.h>
  22
  23 #include "uhttpd.h"
  24
  25 struct handler {
  26         struct list_head list;
  27
  28         struct json_script_file *request;
  29         struct json_script_file *fallback;
  30 };
  31
  32 static LIST_HEAD(handlers);
  33 static struct json_script_ctx handler_ctx;
  34 static struct env_var *cur_vars;
  35 static struct blob_buf b;
  36 static int handler_ret;
  37 static struct client *cur_client;
  38 static char **cur_url;
  39
  40 static void
  41 handle_redirect(struct json_script_ctx *ctx, struct blob_attr *data)
  42 {
  43         struct client *cl = cur_client;
  44         static struct blobmsg_policy policy[3] = {
  45                  { .type = BLOBMSG_TYPE_STRING },
  46                  { .type = BLOBMSG_TYPE_INT32 },
  47                  { .type = BLOBMSG_TYPE_STRING },
  48         };
  49         struct blob_attr *tb[3];
  50         const char *status = "Found";
  51         int code = 302;
  52
  53         blobmsg_parse_array(policy, ARRAY_SIZE(policy), tb, blobmsg_data(data), blobmsg_data_len(data));
  54         if (!tb[0])
  55                 return;
  56
  57         if (tb[1]) {
  58                 code = blobmsg_get_u32(tb[1]);
  59                 if (tb[2])
  60                         status = blobmsg_get_string(tb[2]);
  61         }
  62
  63         uh_http_header(cl, code, status);
  64         ustream_printf(cl->us, "Content-Length: 0\r\n");
  65         ustream_printf(cl->us, "Location: %s\r\n\r\n",
  66                        blobmsg_get_string(tb[0]));
  67         uh_request_done(cl);
  68         *cur_url = NULL;
  69
  70         handler_ret = 1;
  71         json_script_abort(ctx);
  72 }
  73
  74 static void
  75 handle_set_uri(struct json_script_ctx *ctx, struct blob_attr *data)
  76 {
  77         struct client *cl = cur_client;
  78         static struct blobmsg_policy policy = {
  79                  .type = BLOBMSG_TYPE_STRING,
  80         };
  81         struct blob_attr *tb;
  82         struct blob_attr *old_url = blob_data(cl->hdr.head);
  83
  84         blobmsg_parse_array(&policy, 1, &tb, blobmsg_data(data), blobmsg_data_len(data));
  85         if (!tb)
  86                 return;
  87
  88         blob_buf_init(&b, 0);
  89         blob_put_raw(&b, blob_next(old_url), blob_len(cl->hdr.head) - blob_pad_len(old_url));
  90
  91         /* replace URL in client header cache */
  92         blob_buf_init(&cl->hdr, 0);
  93         blobmsg_add_string(&cl->hdr, "URL", blobmsg_get_string(tb));
  94         blob_put_raw(&cl->hdr, blob_data(b.head), blob_len(b.head));
  95         *cur_url = blobmsg_data(blob_data(cl->hdr.head));
  96         cur_vars = NULL;
  97
  98         blob_buf_init(&b, 0);
  99
 100         handler_ret = 1;
 101         json_script_abort(ctx);
 102 }
 103
 104 static void
 105 handle_command(struct json_script_ctx *ctx, const char *name,
 106                struct blob_attr *data, struct blob_attr *vars)
 107 {
 108         static const struct {
 109                 const char *name;
 110                 void (*func)(struct json_script_ctx *ctx, struct blob_attr *data);
 111         } cmds[] = {
 112                 { "redirect", handle_redirect },
 113                 { "rewrite", handle_set_uri }
 114         };
 115         int i;
 116
 117         for (i = 0; i < ARRAY_SIZE(cmds); i++) {
 118                 if (!strcmp(cmds[i].name, name)) {
 119                         cmds[i].func(ctx, data);
 120                         return;
 121                 }
 122         }
 123 }
 124
 125 static const char *
 126 handle_var(struct json_script_ctx *ctx, const char *name,
 127            struct blob_attr *vars)
 128 {
 129         struct client *cl = cur_client;
 130         struct env_var *cur;
 131         static struct path_info empty_path;
 132
 133         if (!cur_vars) {
 134                 struct path_info *p = uh_path_lookup(cl, *cur_url);
 135
 136                 if (!p)
 137                         p = &empty_path;
 138
 139                 cur_vars = uh_get_process_vars(cl, p);
 140         }
 141
 142         for (cur = cur_vars; cur->name; cur++) {
 143                 if (!strcmp(cur->name, name))
 144                         return cur->value;
 145         }
 146         return NULL;
 147 }
 148
 149 static void
 150 handler_init(void)
 151 {
 152         if (handler_ctx.handle_command)
 153                 return;
 154
 155         json_script_init(&handler_ctx);
 156         handler_ctx.handle_command = handle_command;
 157         handler_ctx.handle_var = handle_var;
 158 }
 159
 160 static bool set_handler(struct json_script_file **dest, struct blob_attr *data)
 161 {
 162         if (!data)
 163                 return true;
 164
 165         *dest = json_script_file_from_blobmsg(NULL, blobmsg_data(data), blobmsg_data_len(data));
 166         return *dest;
 167 }
 168
 169 int uh_handler_add(const char *file)
 170 {
 171         enum {
 172                 H_REQUEST,
 173                 H_FALLBACK,
 174                 __H_MAX,
 175         };
 176         struct blobmsg_policy policy[__H_MAX] = {
 177                 [H_REQUEST] = { "request", BLOBMSG_TYPE_ARRAY },
 178                 [H_FALLBACK] = { "fallback", BLOBMSG_TYPE_ARRAY },
 179         };
 180         struct blob_attr *tb[__H_MAX];
 181         struct handler *h;
 182
 183         handler_init();
 184         blob_buf_init(&b, 0);
 185
 186         if (!blobmsg_add_json_from_file(&b, file))
 187                 return -1;
 188
 189         blobmsg_parse(policy, __H_MAX, tb, blob_data(b.head), blob_len(b.head));
 190         if (!tb[H_REQUEST] && !tb[H_FALLBACK])
 191                 return -1;
 192
 193         h = calloc(1, sizeof(*h));
 194         if (!set_handler(&h->request, tb[H_REQUEST]) ||
 195             !set_handler(&h->fallback, tb[H_FALLBACK])) {
 196                 free(h->request);
 197                 free(h->fallback);
 198                 free(h);
 199                 return -1;
 200         }
 201
 202         list_add_tail(&h->list, &handlers);
 203         return 0;
 204 }
 205
 206 int uh_handler_run(struct client *cl, char **url, bool fallback)
 207 {
 208         struct json_script_file *f;
 209         struct handler *h;
 210
 211         cur_client = cl;
 212         cur_url = url;
 213         cur_vars = NULL;
 214
 215         handler_ret = 0;
 216
 217         list_for_each_entry(h, &handlers, list) {
 218                 f = fallback ? h->fallback : h->request;
 219                 if (!f)
 220                         continue;
 221
 222                 blob_buf_init(&b, 0);
 223                 json_script_run_file(&handler_ctx, f, b.head);
 224                 if (handler_ctx.abort)
 225                         break;
 226         }
 227
 228         return handler_ret;
 229 }