cgi.c

   1 /*
   2  * uhttpd - Tiny single-threaded httpd
   3  *
   4  *   Copyright (C) 2010-2012 Jo-Philipp Wich <xm@subsignal.org>
   5  *   Copyright (C) 2012 Felix Fietkau <nbd@openwrt.org>
   6  *
   7  *  Licensed under the Apache License, Version 2.0 (the "License");
   8  *  you may not use this file except in compliance with the License.
   9  *  You may obtain a copy of the License at
  10  *
  11  *      http://www.apache.org/licenses/LICENSE-2.0
  12  *
  13  *  Unless required by applicable law or agreed to in writing, software
  14  *  distributed under the License is distributed on an "AS IS" BASIS,
  15  *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  16  *  See the License for the specific language governing permissions and
  17  *  limitations under the License.
  18  */
  19
  20 #include <libubox/blobmsg.h>
  21 #include "uhttpd.h"
  22
  23 static LIST_HEAD(interpreters);
  24
  25 void uh_interpreter_add(const char *ext, const char *path)
  26 {
  27         struct interpreter *in;
  28         char *new_ext, *new_path;
  29
  30         in = calloc_a(sizeof(*in),
  31                 &new_ext, strlen(ext) + 1,
  32                 &new_path, strlen(path) + 1);
  33
  34         in->ext = strcpy(new_ext, ext);
  35         in->path = strcpy(new_path, path);
  36         list_add_tail(&in->list, &interpreters);
  37 }
  38
  39 static void cgi_main(struct client *cl, struct path_info *pi, int fd)
  40 {
  41         struct interpreter *ip = pi->ip;
  42         struct env_var *var;
  43
  44         dup2(fd, 0);
  45         dup2(fd, 1);
  46         close(fd);
  47         clearenv();
  48         setenv("PATH", conf.cgi_path, 1);
  49
  50         for (var = uh_get_process_vars(cl, pi); var->name; var++) {
  51                 if (!var->value)
  52                         continue;
  53
  54                 setenv(var->name, var->value, 1);
  55         }
  56
  57         chdir(pi->root);
  58
  59         if (ip)
  60                 execl(ip->path, ip->path, pi->phys, NULL);
  61         else
  62                 execl(pi->phys, pi->phys, NULL);
  63
  64         printf("Status: 500 Internal Server Error\r\n\r\n"
  65                "Unable to launch the requested CGI program:\n"
  66                "  %s: %s\n", ip ? ip->path : pi->phys, strerror(errno));
  67 }
  68
  69 static void cgi_handle_request(struct client *cl, const char *url, struct path_info *pi)
  70 {
  71         unsigned int mode = S_IFREG | S_IXOTH;
  72
  73         if (!pi->ip && !((pi->stat.st_mode & mode) == mode)) {
  74                 uh_client_error(cl, 403, "Forbidden",
  75                                 "You don't have permission to access %s on this server.",
  76                                 url);
  77                 return;
  78         }
  79
  80         if (!uh_create_process(cl, pi, cgi_main)) {
  81                 uh_client_error(cl, 500, "Internal Server Error",
  82                                 "Failed to create CGI process: %s", strerror(errno));
  83                 return;
  84         }
  85
  86         return;
  87 }
  88
  89 static bool check_cgi_path(struct path_info *pi, const char *url)
  90 {
  91         struct interpreter *ip;
  92         const char *path = pi->phys;
  93         int path_len = strlen(path);
  94
  95         list_for_each_entry(ip, &interpreters, list) {
  96                 int len = strlen(ip->ext);
  97
  98                 if (len >= path_len)
  99                         continue;
 100
 101                 if (strcmp(path + path_len - len, ip->ext) != 0)
 102                         continue;
 103
 104                 pi->ip = ip;
 105                 return true;
 106         }
 107
 108         pi->ip = NULL;
 109         return uh_path_match(conf.cgi_prefix, url);
 110 }
 111
 112 struct dispatch_handler cgi_dispatch = {
 113         .check_path = check_cgi_path,
 114         .handle_request = cgi_handle_request,
 115 };