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         if (!uh_use_chunked(cl))
  65                 ustream_printf(cl->us, "Content-Length: 0\r\n");
  66         ustream_printf(cl->us, "Location: %s\r\n\r\n",
  67                        blobmsg_get_string(tb[0]));
  68         uh_request_done(cl);
  69         *cur_url = NULL;
  70
  71         handler_ret = 1;
  72         json_script_abort(ctx);
  73 }
  74
  75 static void
  76 handle_set_uri(struct json_script_ctx *ctx, struct blob_attr *data)
  77 {
  78         struct client *cl = cur_client;
  79         static struct blobmsg_policy policy = {
  80                  .type = BLOBMSG_TYPE_STRING,
  81         };
  82         struct blob_attr *tb;
  83         struct blob_attr *old_url = blob_data(cl->hdr.head);
  84
  85         blobmsg_parse_array(&policy, 1, &tb, blobmsg_data(data), blobmsg_data_len(data));
  86         if (!tb)
  87                 return;
  88
  89         blob_buf_init(&b, 0);
  90         blob_put_raw(&b, blob_next(old_url), blob_len(cl->hdr.head) - blob_pad_len(old_url));
  91
  92         /* replace URL in client header cache */
  93         blob_buf_init(&cl->hdr, 0);
  94         blobmsg_add_string(&cl->hdr, "URL", blobmsg_get_string(tb));
  95         blob_put_raw(&cl->hdr, blob_data(b.head), blob_len(b.head));
  96         *cur_url = blobmsg_data(blob_data(cl->hdr.head));
  97         cur_vars = NULL;
  98
  99         blob_buf_init(&b, 0);
 100
 101         handler_ret = 1;
 102         json_script_abort(ctx);
 103 }
 104
 105 static void
 106 handle_command(struct json_script_ctx *ctx, const char *name,
 107                struct blob_attr *data, struct blob_attr *vars)
 108 {
 109         static const struct {
 110                 const char *name;
 111                 void (*func)(struct json_script_ctx *ctx, struct blob_attr *data);
 112         } cmds[] = {
 113                 { "redirect", handle_redirect },
 114                 { "rewrite", handle_set_uri }
 115         };
 116         int i;
 117
 118         for (i = 0; i < ARRAY_SIZE(cmds); i++) {
 119                 if (!strcmp(cmds[i].name, name)) {
 120                         cmds[i].func(ctx, data);
 121                         return;
 122                 }
 123         }
 124 }
 125
 126 static const char *
 127 handle_var(struct json_script_ctx *ctx, const char *name,
 128            struct blob_attr *vars)
 129 {
 130         struct client *cl = cur_client;
 131         struct env_var *cur;
 132         static struct path_info empty_path;
 133
 134         if (!cur_vars) {
 135                 struct path_info *p = uh_path_lookup(cl, *cur_url);
 136
 137                 if (!p)
 138                         p = &empty_path;
 139
 140                 cur_vars = uh_get_process_vars(cl, p);
 141         }
 142
 143         for (cur = cur_vars; cur->name; cur++) {
 144                 if (!strcmp(cur->name, name))
 145                         return cur->value;
 146         }
 147         return NULL;
 148 }
 149
 150 static void
 151 handler_init(void)
 152 {
 153         if (handler_ctx.handle_command)
 154                 return;
 155
 156         json_script_init(&handler_ctx);
 157         handler_ctx.handle_command = handle_command;
 158         handler_ctx.handle_var = handle_var;
 159 }
 160
 161 static bool set_handler(struct json_script_file **dest, struct blob_attr *data)
 162 {
 163         if (!data)
 164                 return true;
 165
 166         *dest = json_script_file_from_blobmsg(NULL, blobmsg_data(data), blobmsg_data_len(data));
 167         return *dest;
 168 }
 169
 170 int uh_handler_add(const char *file)
 171 {
 172         enum {
 173                 H_REQUEST,
 174                 H_FALLBACK,
 175                 __H_MAX,
 176         };
 177         struct blobmsg_policy policy[__H_MAX] = {
 178                 [H_REQUEST] = { "request", BLOBMSG_TYPE_ARRAY },
 179                 [H_FALLBACK] = { "fallback", BLOBMSG_TYPE_ARRAY },
 180         };
 181         struct blob_attr *tb[__H_MAX];
 182         struct handler *h;
 183
 184         handler_init();
 185         blob_buf_init(&b, 0);
 186
 187         if (!blobmsg_add_json_from_file(&b, file))
 188                 return -1;
 189
 190         blobmsg_parse(policy, __H_MAX, tb, blob_data(b.head), blob_len(b.head));
 191         if (!tb[H_REQUEST] && !tb[H_FALLBACK])
 192                 return -1;
 193
 194         h = calloc(1, sizeof(*h));
 195         if (!set_handler(&h->request, tb[H_REQUEST]) ||
 196             !set_handler(&h->fallback, tb[H_FALLBACK])) {
 197                 free(h->request);
 198                 free(h->fallback);
 199                 free(h);
 200                 return -1;
 201         }
 202
 203         list_add_tail(&h->list, &handlers);
 204         return 0;
 205 }
 206
 207 int uh_handler_run(struct client *cl, char **url, bool fallback)
 208 {
 209         struct json_script_file *f;
 210         struct handler *h;
 211
 212         cur_client = cl;
 213         cur_url = url;
 214         cur_vars = NULL;
 215
 216         handler_ret = 0;
 217
 218         list_for_each_entry(h, &handlers, list) {
 219                 f = fallback ? h->fallback : h->request;
 220                 if (!f)
 221                         continue;
 222
 223                 blob_buf_init(&b, 0);
 224                 json_script_run_file(&handler_ctx, f, b.head);
 225                 if (handler_ctx.abort)
 226                         break;
 227         }
 228
 229         return handler_ret;
 230 }