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

   1 /*
   2  * Usage: as CGI script
   3  */
   4 /*
   5  * Copyright 1996-2013,2016 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  * Copyright 2013,2016 Mark Wooding <mdw@distorted.org.uk>
  11  *
  12  * This is free software; you can redistribute it and/or modify it
  13  * under the terms of the GNU General Public License as published by
  14  * the Free Software Foundation; either version 3 of the License, or
  15  * (at your option) any later version.
  16  *
  17  * This program is distributed in the hope that it will be useful, but
  18  * WITHOUT ANY WARRANTY; without even the implied warranty of
  19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  20  * General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU General Public License
  23  * along with userv-utils; if not, see http://www.gnu.org/licenses/.
  24  */
  25
  26 #include <stdio.h>
  27 #include <string.h>
  28 #include <ctype.h>
  29 #include <unistd.h>
  30 #include <sys/types.h>
  31 #include <sys/wait.h>
  32
  33 #include "ucgi.h"
  34
  35 static const char *const default_envok[] = {
  36   "AUTH_TYPE",
  37   "CONTENT_TYPE",
  38   "CONTENT_LENGTH",
  39   "DOCUMENT_ROOT",
  40   "GATEWAY_INTERFACE",
  41   "HTTP_*",
  42   "HTTPS",
  43   "PATH_INFO",
  44   "PATH_TRANSLATED",
  45   "QUERY_STRING",
  46   "REDIRECT_*",
  47   "REMOTE_*",
  48   "REQUEST_METHOD",
  49   "REQUEST_URI",
  50   "SCRIPT_*",
  51   "SERVER_*",
  52   "SSL_*",
  53   0
  54 };
  55
  56 struct buildargs {
  57   const char **v;
  58   int n, max;
  59 };
  60
  61 static void addarg(struct buildargs *args, const char *a) {
  62   if (args->n > args->max) error("too many arguments", 500);
  63   args->v[args->n++]= a;
  64 }
  65
  66 static void add_userv_var(const char *fulln,
  67                           const char *en, const char *ev, void *p) {
  68   struct buildargs *args= p;
  69   size_t l;
  70   char *a;
  71
  72   l= strlen(ev);
  73   if (l > MAX_ENVVAR_VALUE) error("environment variable too long", 500);
  74   a= xmalloc(strlen(en)+l+6);
  75   sprintf(a,"-DE_%s=%s",en,ev);
  76   addarg(args, a);
  77 }
  78
  79 int main(int argc, const char **argv) {
  80   char *username;
  81   const char *slash2, *pathi, *ev, *av;
  82   const char *const *envok = 0;
  83   size_t usernamelen, l;
  84   struct buildargs args;
  85   pid_t child, rchild;
  86   int status;
  87
  88   l= strlen(argv[0]);
  89   if (l>6 && !strcmp(argv[0]+l-6,"-debug")) debugmode= 1;
  90
  91   if (debugmode) {
  92     if (fputs("Content-Type: text/plain\n\n",stdout)==EOF || fflush(stdout))
  93       syserror("write stdout");
  94     if (dup2(1,2)<0) { perror("dup stdout to stderr"); exit(-1); }
  95     D( printf(";;; UCGI\n"); )
  96   }
  97
  98   if (argc > MAX_ARGS) error("too many arguments", 500);
  99
 100   ev= getenv("UCGI_ENV_FILTER");
 101   if (ev)
 102     envok= load_filters(LOADF_MUST, ev, LF_END);
 103   else
 104     envok= load_filters(0, "/etc/userv/ucgi.env-filter", LF_END);
 105
 106   pathi= getenv("PATH_INFO");
 107   if (!pathi) error("PATH_INFO not found", 500);
 108   D( if (debugmode) {
 109        printf(";; find user name...\n"
 110               ";;   initial PATH_INFO = `%s'\n",
 111               pathi);
 112   } )
 113   if (pathi[0] != '/' || pathi[1] != '~')
 114     error("PATH_INFO must start with /~", 400);
 115   slash2= strchr(pathi+2,'/');
 116   if (!slash2) error("PATH_INFO must have more than one /", 400);
 117   usernamelen= slash2-(pathi+2);
 118   if (usernamelen > MAX_USERNAME_LEN) error("PATH_INFO username too long", 400);
 119   username= xmalloc(usernamelen+1);
 120   memcpy(username,pathi+2,usernamelen); username[usernamelen]= 0;
 121   D( if (debugmode)
 122        printf(";;   user = `%s'; tail = `%s'\n", username, slash2); )
 123   if (!isalpha(username[0]))
 124     error("username 1st character is not alphabetic", 400);
 125   xsetenv("PATH_INFO",slash2,1);
 126
 127   args.n= 0; args.max= argc + MAX_ENVVARS + 10;
 128   args.v= xmalloc(args.max * sizeof(*args.v));
 129
 130   addarg(&args, "userv");
 131   if (debugmode) addarg(&args, "-DDEBUG=1");
 132
 133   filter_environment(FILTF_WILDCARD, "", envok, default_envok,
 134                      add_userv_var, &args);
 135
 136   addarg(&args, username);
 137   addarg(&args, "www-cgi");
 138   while ((av= (*++argv))) addarg(&args, av);
 139   addarg(&args, 0);
 140
 141   if (debugmode) {
 142     D( fflush(stdout); )
 143     child= fork(); if (child==-1) syserror("fork");
 144     if (child) {
 145       rchild= waitpid(child,&status,0);
 146       if (rchild==-1) syserror("waitpid");
 147       printf("\nexit status %d %d\n",(status>>8)&0x0ff,status&0x0ff);
 148       exit(0);
 149     }
 150   }
 151
 152   D( if (debugmode) {
 153        int i;
 154
 155        printf(";; final command line...\n");
 156        for (i = 0; args.v[i]; i++)
 157          printf(";;   %s\n", args.v[i]);
 158        fflush(stdout);
 159   } )
 160
 161   execvp("userv",(char*const*)args.v);
 162   syserror("exec userv");
 163   return -1;
 164 }