mdw@git.distorted.org.uk Git - userv-utils/blob - www-cgi/ucgi.c

   1 /*
   2  * Usage: as CGI script
   3  */
   4 /*
   5  * Copyright 1996-2013 Ian Jackson <ijackson@chiark.greenend.org.uk>
   6  * Copyright 1998 David Damerell <damerell@chiark.greenend.org.uk>
   7  * Copyright 1999,2003
   8  *    Chancellor Masters and Scholars of the University of Cambridge
   9  * Copyright 2010 Tony Finch <fanf@dotat.at>
  10  *
  11  * This is free software; you can redistribute it and/or modify it
  12  * under the terms of the GNU General Public License as published by
  13  * the Free Software Foundation; either version 3 of the License, or
  14  * (at your option) any later version.
  15  *
  16  * This program is distributed in the hope that it will be useful, but
  17  * WITHOUT ANY WARRANTY; without even the implied warranty of
  18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  19  * General Public License for more details.
  20  *
  21  * You should have received a copy of the GNU General Public License
  22  * along with userv-utils; if not, see http://www.gnu.org/licenses/.
  23  */
  24
  25 #include <stdio.h>
  26 #include <string.h>
  27 #include <ctype.h>
  28 #include <unistd.h>
  29 #include <sys/types.h>
  30 #include <sys/wait.h>
  31
  32 #include "ucgi.h"
  33
  34 static const char *const default_envok[] = {
  35   "AUTH_TYPE",
  36   "CONTENT_TYPE",
  37   "CONTENT_LENGTH",
  38   "DOCUMENT_ROOT",
  39   "GATEWAY_INTERFACE",
  40   "HTTP_*",
  41   "HTTPS",
  42   "PATH_INFO",
  43   "PATH_TRANSLATED",
  44   "QUERY_STRING",
  45   "REDIRECT_*",
  46   "REMOTE_*",
  47   "REQUEST_METHOD",
  48   "REQUEST_URI",
  49   "SCRIPT_*",
  50   "SERVER_*",
  51   "SSL_*",
  52   0
  53 };
  54
  55 struct buildargs {
  56   const char **v;
  57   int n, max;
  58 };
  59
  60 static void addarg(struct buildargs *args, const char *a) {
  61   if (args->n > args->max) error("too many arguments", 500);
  62   args->v[args->n++]= a;
  63 }
  64
  65 static void add_userv_var(const char *fulln,
  66                           const char *en, const char *ev, void *p) {
  67   struct buildargs *args= p;
  68   size_t l;
  69   char *a;
  70
  71   l= strlen(ev);
  72   if (l > MAX_ENVVAR_VALUE) error("environment variable too long", 500);
  73   a= xmalloc(strlen(en)+l+6);
  74   sprintf(a,"-DE_%s=%s",en,ev);
  75   addarg(args, a);
  76 }
  77
  78 int main(int argc, const char **argv) {
  79   char *username;
  80   const char *slash2, *pathi, *ev, *av;
  81   const char *const *envok = 0;
  82   size_t usernamelen, l;
  83   struct buildargs args;
  84   pid_t child, rchild;
  85   int status;
  86
  87   l= strlen(argv[0]);
  88   if (l>6 && !strcmp(argv[0]+l-6,"-debug")) debugmode= 1;
  89
  90   if (debugmode) {
  91     if (fputs("Content-Type: text/plain\n\n",stdout)==EOF || fflush(stdout))
  92       syserror("write stdout");
  93     if (dup2(1,2)<0) { perror("dup stdout to stderr"); exit(-1); }
  94     D( printf(";;; UCGI\n"); )
  95   }
  96
  97   if (argc > MAX_ARGS) error("too many arguments", 500);
  98
  99   ev= getenv("UCGI_ENV_FILTER");
 100   if (ev)
 101     envok= load_filters(LOADF_MUST, ev, LF_END);
 102   else
 103     envok= load_filters(0, "/etc/userv/ucgi.env-filter", LF_END);
 104
 105   pathi= getenv("PATH_INFO");
 106   if (!pathi) error("PATH_INFO not found", 500);
 107   D( if (debugmode) {
 108        printf(";; find user name...\n"
 109               ";;   initial PATH_INFO = `%s'\n",
 110               pathi);
 111   } )
 112   if (pathi[0] != '/' || pathi[1] != '~')
 113     error("PATH_INFO must start with /~", 400);
 114   slash2= strchr(pathi+2,'/');
 115   if (!slash2) error("PATH_INFO must have more than one /", 400);
 116   usernamelen= slash2-(pathi+2);
 117   if (usernamelen > MAX_USERNAME_LEN) error("PATH_INFO username too long", 400);
 118   username= xmalloc(usernamelen+1);
 119   memcpy(username,pathi+2,usernamelen); username[usernamelen]= 0;
 120   D( if (debugmode)
 121        printf(";;   user = `%s'; tail = `%s'\n", username, slash2); )
 122   if (!isalpha(username[0]))
 123     error("username 1st character is not alphabetic", 400);
 124   xsetenv("PATH_INFO",slash2,1);
 125
 126   args.n= 0; args.max= argc + MAX_ENVVARS + 10;
 127   args.v= xmalloc(args.max * sizeof(*args.v));
 128
 129   addarg(&args, "userv");
 130   if (debugmode) addarg(&args, "-DDEBUG=1");
 131
 132   filter_environment(FILTF_WILDCARD, "", envok, default_envok,
 133                      add_userv_var, &args);
 134
 135   addarg(&args, username);
 136   addarg(&args, "www-cgi");
 137   while ((av= (*++argv))) addarg(&args, av);
 138   addarg(&args, 0);
 139
 140   if (debugmode) {
 141     D( fflush(stdout); )
 142     child= fork(); if (child==-1) syserror("fork");
 143     if (child) {
 144       rchild= waitpid(child,&status,0);
 145       if (rchild==-1) syserror("waitpid");
 146       printf("\nexit status %d %d\n",(status>>8)&0x0ff,status&0x0ff);
 147       exit(0);
 148     }
 149   }
 150
 151   D( if (debugmode) {
 152        int i;
 153
 154        printf(";; final command line...\n");
 155        for (i = 0; args.v[i]; i++)
 156          printf(";;   %s\n", args.v[i]);
 157        fflush(stdout);
 158   } )
 159
 160   execvp("userv",(char*const*)args.v);
 161   syserror("exec userv");
 162   return -1;
 163 }