cgi/snapshot.cgi

   1 #!/bin/sh
   2
   3 # snapshot.cgi -- throttle snapshot requests
   4 # Copyright (C) 2015 Kyle J. McKay.  All rights reserved.
   5 # License GPLv2+: GNU GPL version 2 or later.
   6 # www.gnu.org/licenses/gpl-2.0.html
   7 # This is free software: you are free to change and redistribute it.
   8 # There is NO WARRANTY, to the extent permitted by law.
   9
  10 set -e
  11
  12 . @basedir@/shlib.sh
  13
  14 # Set to non-empty to throttle if the initial throttle service connect fails
  15 throttle_on_connect_fail=
  16
  17 # Supplemental message to be included in the throttle result
  18 throttle_msg=\
  19 'Ravenous roving robots are probably greedily chowing down on our services
  20 right now.
  21
  22 We are valiantly trying to fight them off to improve service availability.'
  23
  24 errorhdrsct()
  25 {
  26         _ct="$1"; shift
  27         printf '%s\r\n' "Status: $1 $2"
  28         printf '%s\r\n' "Expires: Fri, 01 Jan 1980 00:00:00 GMT"
  29         printf '%s\r\n' "Pragma: no-cache"
  30         printf '%s\r\n' "Cache-Control: no-cache,max-age=0,must-revalidate"
  31         [ -z "$3" ] || printf '%s\r\n' "$3"
  32         printf '%s\r\n' "Content-Type: $_ct"
  33         printf '\r\n'
  34 }
  35
  36 errorhdrs()
  37 {
  38         errorhdrsct 'text/plain' "$@"
  39 }
  40
  41 msglines()
  42 {
  43         while [ $# -gt 0 ]; do
  44                 printf '%s\n' "$1"
  45                 shift
  46         done
  47 }
  48
  49 methodnotallowed()
  50 {
  51         errorhdrs 405 "Method Not Allowed" "Allow: GET"
  52         if [ $# -eq 0 ]; then
  53                 msglines "Method Not Allowed"
  54         else
  55                 msglines "$@"
  56         fi
  57         exit 0
  58 }
  59
  60 forbidden()
  61 {
  62         errorhdrs 403 Forbidden
  63         if [ $# -eq 0 ]; then
  64                 msglines "Forbidden"
  65         else
  66                 msglines "$@"
  67         fi
  68         exit 0
  69 }
  70
  71 notfound()
  72 {
  73         errorhdrs 404 "Not Found"
  74         if [ $# -eq 0 ]; then
  75                 msglines "Not Found"
  76         else
  77                 msglines "$@"
  78         fi
  79         exit 0
  80 }
  81
  82 # Snapshots are too expensive to allow HEAD
  83 [ "$REQUEST_METHOD" = "GET" ] || methodnotallowed
  84
  85 # The project must be valid
  86 suffix="${PATH_INFO#*.git/}"
  87 project="${PATH_INFO%/$suffix}"
  88 project="${project#/}"
  89 [ -n "$project" ] || forbidden
  90 case "$suffix" in snapshot|snapshot/*) :;; *) forbidden; esac
  91 suffix="${suffix#snapshot}"
  92 suffix="${suffix#/}"
  93
  94 # Perform some basic sanity checking
  95 if [ -z "$suffix" ]; then
  96         # Must have an "h=" argument
  97         case "&$QUERY_STRING&" in *[\&\;]"h="[!\&\;]*) :;; *) forbidden; esac
  98 fi
  99 case "$suffix" in [!A-Za-z0-9_]*) forbidden; esac
 100 case "/$project/" in *"/../"*|*"/./"*|*"/_"*|*"//"*) forbidden; esac
 101 is_git_dir "$cfg_reporoot/$project" || notfound
 102
 103 # Off to the races
 104 projname="${project%.git}"
 105 "$cfg_basedir/bin/throttle" ${throttle_on_connect_fail:+-t} -c snapshot \
 106         -d "$projname" -m "$throttle_msg" "$cfg_cgiroot/gitweb.cgi"
 107 exit 0