about summary refs log tree commit diff stats
path: root/src/loader/cgi.nim
blob: c266c0f61cf1f278800ce9dd4a348c01479602f8 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
import std/options
import std/os
import std/posix
import std/streams
import std/strutils

import extern/stdio
import io/posixstream
import loader/connecterror
import loader/headers
import loader/loaderhandle
import loader/request
import types/formdata
import types/opt
import types/url
import utils/twtstr

proc putMappedURL(url: URL) =
  putEnv("MAPPED_URI_SCHEME", url.scheme)
  putEnv("MAPPED_URI_USERNAME", url.username)
  putEnv("MAPPED_URI_PASSWORD", url.password)
  putEnv("MAPPED_URI_HOST", url.hostname)
  putEnv("MAPPED_URI_PORT", url.port)
  putEnv("MAPPED_URI_PATH", url.path.serialize())
  putEnv("MAPPED_URI_QUERY", url.query.get(""))

proc setupEnv(cmd, scriptName, pathInfo, requestURI, libexecPath: string,
    request: Request, contentLen: int, prevURL: URL) =
  let url = request.url
  putEnv("SERVER_SOFTWARE", "Chawan")
  putEnv("SERVER_PROTOCOL", "HTTP/1.0")
  putEnv("SERVER_NAME", "localhost")
  putEnv("SERVER_PORT", "80")
  putEnv("REMOTE_HOST", "localhost")
  putEnv("REMOTE_ADDR", "127.0.0.1")
  putEnv("GATEWAY_INTERFACE", "CGI/1.1")
  putEnv("SCRIPT_NAME", scriptName)
  putEnv("SCRIPT_FILENAME", cmd)
  putEnv("REQUEST_URI", requestURI)
  putEnv("REQUEST_METHOD", $request.httpMethod)
  putEnv("CHA_LIBEXEC_DIR", libexecPath)
  var headers = ""
  for k, v in request.headers:
    headers &= k & ": " & v & "\r\n"
  putEnv("REQUEST_HEADERS", headers)
  if prevURL != nil:
    putMappedURL(prevURL)
  if pathInfo != "":
    putEnv("PATH_INFO", pathInfo)
  if url.query.isSome:
    putEnv("QUERY_STRING", url.query.get)
  if request.httpMethod == HTTP_POST:
    if request.multipart.isSome:
      putEnv("CONTENT_TYPE", request.multipart.get.getContentType())
    else:
      putEnv("CONTENT_TYPE", request.headers.getOrDefault("Content-Type", ""))
    putEnv("CONTENT_LENGTH", $contentLen)
  if "Cookie" in request.headers:
    putEnv("HTTP_COOKIE", request.headers["Cookie"])
  if request.referer != nil:
    putEnv("HTTP_REFERER", $request.referer)
  if request.proxy != nil:
    putEnv("ALL_PROXY", $request.proxy)

type ControlResult = enum
  RESULT_CONTROL_DONE, RESULT_CONTROL_CONTINUE, RESULT_ERROR

proc handleFirstLine(handle: LoaderHandle, line: string, headers: Headers,
    status: var int): ControlResult =
  let k = line.until(':')
  if k.len == line.len:
    # invalid
    handle.sendResult(ERROR_CGI_MALFORMED_HEADER)
    return RESULT_ERROR
  let v = line.substr(k.len + 1).strip()
  if k.equalsIgnoreCase("Status"):
    handle.sendResult(0) # success
    status = parseInt32(v).get(0)
    return RESULT_CONTROL_CONTINUE
  if k.equalsIgnoreCase("Cha-Control"):
    if v.startsWithIgnoreCase("Connected"):
      handle.sendResult(0) # success
      return RESULT_CONTROL_CONTINUE
    elif v.startsWithIgnoreCase("ConnectionError"):
      let errs = v.split(' ')
      if errs.len <= 1:
        handle.sendResult(ERROR_CGI_INVALID_CHA_CONTROL)
      else:
        let fb = int32(ERROR_CGI_INVALID_CHA_CONTROL)
        let code = int(parseInt32(errs[1]).get(fb))
        var message = ""
        if errs.len > 2:
          message &= errs[2]
          for i in 3 ..< errs.len:
            message &= ' '
            message &= errs[i]
        handle.sendResult(code, message)
      return RESULT_ERROR
    elif v.startsWithIgnoreCase("ControlDone"):
      return RESULT_CONTROL_DONE
    handle.sendResult(ERROR_CGI_INVALID_CHA_CONTROL)
    return RESULT_ERROR
  handle.sendResult(0) # success
  headers.add(k, v)
  return RESULT_CONTROL_DONE

proc handleControlLine(handle: LoaderHandle, line: string, headers: Headers,
    status: var int): ControlResult =
  let k = line.until(':')
  if k.len == line.len:
    # invalid
    return RESULT_ERROR
  let v = line.substr(k.len + 1).strip()
  if k.equalsIgnoreCase("Status"):
    status = parseInt32(v).get(0)
    return RESULT_CONTROL_CONTINUE
  if k.equalsIgnoreCase("Cha-Control"):
    if v.startsWithIgnoreCase("ControlDone"):
      return RESULT_CONTROL_DONE
    return RESULT_ERROR
  headers.add(k, v)
  return RESULT_CONTROL_DONE

# returns false if transfer was interrupted
proc handleLine(handle: LoaderHandle, line: string, headers: Headers) =
  let k = line.until(':')
  if k.len == line.len:
    # invalid
    return
  let v = line.substr(k.len + 1).strip()
  headers.add(k, v)

proc loadCGI*(handle: LoaderHandle, request: Request, cgiDir: seq[string],
    libexecPath: string, prevURL: URL) =
  if cgiDir.len == 0:
    handle.sendResult(ERROR_NO_CGI_DIR)
    return
  var path = percentDecode(request.url.pathname)
  if path.startsWith("/cgi-bin/"):
    path.delete(0 .. "/cgi-bin/".high)
  elif path.startsWith("/$LIB/"):
    path.delete(0 .. "/$LIB/".high)
  if path == "" or request.url.hostname != "":
    handle.sendResult(ERROR_INVALID_CGI_PATH)
    return
  var basename: string
  var pathInfo: string
  var cmd: string
  var scriptName: string
  var requestURI: string
  if path[0] == '/':
    for dir in cgiDir:
      if path.startsWith(dir):
        basename = path.substr(dir.len).until('/')
        pathInfo = path.substr(dir.len + basename.len)
        cmd = dir / basename
        if not fileExists(cmd):
          continue
        scriptName = path.substr(0, dir.len + basename.len)
        requestURI = cmd / pathInfo & request.url.search
        break
    if cmd == "":
      handle.sendResult(ERROR_INVALID_CGI_PATH)
      return
  else:
    basename = path.until('/')
    pathInfo = path.substr(basename.len)
    scriptName = "/cgi-bin/" & basename
    requestURI = "/cgi-bin/" & path & request.url.search
    for dir in cgiDir:
      cmd = dir / basename
      if fileExists(cmd):
        break
  if not fileExists(cmd):
    handle.sendResult(ERROR_CGI_FILE_NOT_FOUND)
    return
  if basename in ["", ".", ".."] or basename.startsWith("~"):
    handle.sendResult(ERROR_INVALID_CGI_PATH)
    return
  var pipefd: array[0..1, cint] # child -> parent
  if pipe(pipefd) == -1:
    handle.sendResult(ERROR_FAIL_SETUP_CGI)
    return
  # Pipe the request body as stdin for POST.
  var pipefd_read: array[0..1, cint] # parent -> child
  let needsPipe = request.body.isSome or request.multipart.isSome
  if needsPipe:
    if pipe(pipefd_read) == -1:
      handle.sendResult(ERROR_FAIL_SETUP_CGI)
      return
  var contentLen = 0
  if request.body.isSome:
    contentLen = request.body.get.len
  elif request.multipart.isSome:
    contentLen = request.multipart.get.calcLength()
  let pid = fork()
  if pid == -1:
    handle.sendResult(ERROR_FAIL_SETUP_CGI)
  elif pid == 0:
    discard close(pipefd[0]) # close read
    discard dup2(pipefd[1], 1) # dup stdout
    if needsPipe:
      discard close(pipefd_read[1]) # close write
      if pipefd_read[0] != 0:
        discard dup2(pipefd_read[0], 0) # dup stdin
        discard close(pipefd_read[0])
    else:
      closeStdin()
    # we leave stderr open, so it can be seen in the browser console
    setupEnv(cmd, scriptName, pathInfo, requestURI, libexecPath, request,
      contentLen, prevURL)
    discard execl(cstring(cmd), cstring(basename), nil)
    let code = int(ERROR_FAILED_TO_EXECUTE_CGI_SCRIPT)
    stdout.write("Cha-Control: ConnectionError " & $code)
    quit(1)
  else:
    discard close(pipefd[1]) # close write
    if needsPipe:
      discard close(pipefd_read[0]) # close read
      let ps = newPosixStream(pipefd_read[1])
      if request.body.isSome:
        ps.write(request.body.get)
      elif request.multipart.isSome:
        let multipart = request.multipart.get
        for entry in multipart.entries:
          ps.writeEntry(entry, multipart.boundary)
      ps.close()
    let ps = newPosixStream(pipefd[0])
    let headers = newHeaders()
    var status = 200
    if ps.atEnd:
      # no data?
      handle.sendResult(ERROR_CGI_NO_DATA)
      return
    let line = ps.readLine()
    if line == "": #\r\n
      # no headers, body comes immediately
      handle.sendResult(0) # success
    else:
      var res = handle.handleFirstLine(line, headers, status)
      if res == RESULT_ERROR:
        return
      var crlfFound = false
      while not ps.atEnd and res == RESULT_CONTROL_CONTINUE:
        let line = ps.readLine()
        if line == "":
          crlfFound = true
          break
        res = handle.handleControlLine(line, headers, status)
        if res == RESULT_ERROR:
          return
      if not crlfFound:
        while not ps.atEnd:
          let line = ps.readLine()
          if line == "": #\r\n
            break
          handle.handleLine(line, headers)
    handle.sendStatus(status)
    handle.sendHeaders(headers)
    if not ps.atEnd():
      handle.istream = ps