cgi.c

   1 /*
   2  * uhttpd - Tiny single-threaded httpd
   3  *
   4  *   Copyright (C) 2010-2013 Jo-Philipp Wich <xm@subsignal.org>
   5  *   Copyright (C) 2013 Felix Fietkau <nbd@openwrt.org>
   6  *
   7  * Permission to use, copy, modify, and/or distribute this software for any
   8  * purpose with or without fee is hereby granted, provided that the above
   9  * copyright notice and this permission notice appear in all copies.
  10  *
  11  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  12  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  13  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  14  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  15  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  16  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  17  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  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, char *url)
  40 {
  41         const struct interpreter *ip = pi->ip;
  42         struct env_var *var;
  43
  44         clearenv();
  45         setenv("PATH", conf.cgi_path, 1);
  46
  47         for (var = uh_get_process_vars(cl, pi); var->name; var++) {
  48                 if (!var->value)
  49                         continue;
  50
  51                 setenv(var->name, var->value, 1);
  52         }
  53
  54         chdir(pi->root);
  55
  56         if (ip)
  57                 execl(ip->path, ip->path, pi->phys, NULL);
  58         else
  59                 execl(pi->phys, pi->phys, NULL);
  60
  61         printf("Status: 500 Internal Server Error\r\n\r\n"
  62                "Unable to launch the requested CGI program:\n"
  63                "  %s: %s\n", ip ? ip->path : pi->phys, strerror(errno));
  64 }
  65
  66 static void cgi_handle_request(struct client *cl, char *url, struct path_info *pi)
  67 {
  68         unsigned int mode = S_IFREG | S_IXOTH;
  69
  70         if (!pi->ip && !((pi->stat.st_mode & mode) == mode)) {
  71                 uh_client_error(cl, 403, "Forbidden",
  72                                 "You don't have permission to access %s on this server.",
  73                                 url);
  74                 return;
  75         }
  76
  77         if (!uh_create_process(cl, pi, url, cgi_main)) {
  78                 uh_client_error(cl, 500, "Internal Server Error",
  79                                 "Failed to create CGI process: %s", strerror(errno));
  80                 return;
  81         }
  82
  83         return;
  84 }
  85
  86 static bool check_cgi_path(struct path_info *pi, const char *url)
  87 {
  88         struct interpreter *ip;
  89         const char *path = pi->phys;
  90         int path_len = strlen(path);
  91
  92         list_for_each_entry(ip, &interpreters, list) {
  93                 int len = strlen(ip->ext);
  94
  95                 if (len >= path_len)
  96                         continue;
  97
  98                 if (strcmp(path + path_len - len, ip->ext) != 0)
  99                         continue;
 100
 101                 pi->ip = ip;
 102                 return true;
 103         }
 104
 105         pi->ip = NULL;
 106         return uh_path_match(conf.cgi_docroot_path, pi->phys);
 107 }
 108
 109 struct dispatch_handler cgi_dispatch = {
 110         .script = true,
 111         .check_path = check_cgi_path,
 112         .handle_request = cgi_handle_request,
 113 };