toolkit/components/remote/RemoteUtils.cpp

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim:expandtab:shiftwidth=2:tabstop=8:
   3  */
   4 /* vim:set ts=8 sw=2 et cindent: */
   5 /* This Source Code Form is subject to the terms of the Mozilla Public
   6  * License, v. 2.0. If a copy of the MPL was not distributed with this
   7  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   8
   9 #include <stdlib.h>
  10 #include <string.h>
  11 #include <unistd.h>
  12 #include <limits.h>
  13
  14 #include "RemoteUtils.h"
  15
  16 #ifdef IS_BIG_ENDIAN
  17 #  define TO_LITTLE_ENDIAN32(x)                               \
  18     ((((x) & 0xff000000) >> 24) | (((x) & 0x00ff0000) >> 8) | \
  19      (((x) & 0x0000ff00) << 8) | (((x) & 0x000000ff) << 24))
  20 #else
  21 #  define TO_LITTLE_ENDIAN32(x) (x)
  22 #endif
  23
  24 #ifndef MAX_PATH
  25 #  ifdef PATH_MAX
  26 #    define MAX_PATH PATH_MAX
  27 #  else
  28 #    define MAX_PATH 1024
  29 #  endif
  30 #endif
  31
  32 /* like strcpy, but return the char after the final null */
  33 static char* estrcpy(const char* s, char* d) {
  34   while (*s) *d++ = *s++;
  35
  36   *d++ = '\0';
  37   return d;
  38 }
  39
  40 /* Construct a command line from given args and desktop startup ID.
  41  * Returned buffer must be released by free().
  42  */
  43 char* ConstructCommandLine(int32_t argc, const char** argv,
  44                            const char* aStartupToken, int* aCommandLineLength) {
  45   char cwdbuf[MAX_PATH];
  46   if (!getcwd(cwdbuf, MAX_PATH)) return nullptr;
  47
  48   // the commandline property is constructed as an array of int32_t
  49   // followed by a series of null-terminated strings:
  50   //
  51   // [argc][offsetargv0][offsetargv1...]<workingdir>\0<argv[0]>\0argv[1]...\0
  52   // (offset is from the beginning of the buffer)
  53
  54   static char startupTokenPrefix[] = " STARTUP_TOKEN=";
  55
  56   int32_t argvlen = strlen(cwdbuf);
  57   for (int i = 0; i < argc; ++i) {
  58     int32_t len = strlen(argv[i]);
  59     if (i == 0 && aStartupToken) {
  60       len += sizeof(startupTokenPrefix) - 1 + strlen(aStartupToken);
  61     }
  62     argvlen += len;
  63   }
  64
  65   auto* buffer =
  66       (int32_t*)malloc(argvlen + argc + 1 + sizeof(int32_t) * (argc + 1));
  67   if (!buffer) return nullptr;
  68
  69   buffer[0] = TO_LITTLE_ENDIAN32(argc);
  70
  71   auto* bufend = (char*)(buffer + argc + 1);
  72
  73   bufend = estrcpy(cwdbuf, bufend);
  74
  75   for (int i = 0; i < argc; ++i) {
  76     buffer[i + 1] = TO_LITTLE_ENDIAN32(bufend - ((char*)buffer));
  77     bufend = estrcpy(argv[i], bufend);
  78     if (i == 0 && aStartupToken) {
  79       bufend = estrcpy(startupTokenPrefix, bufend - 1);
  80       bufend = estrcpy(aStartupToken, bufend - 1);
  81     }
  82   }
  83
  84 #ifdef DEBUG_command_line
  85   int32_t debug_argc = TO_LITTLE_ENDIAN32(*buffer);
  86   char* debug_workingdir = (char*)(buffer + argc + 1);
  87
  88   printf(
  89       "Sending command line:\n"
  90       "  working dir: %s\n"
  91       "  argc:\t%i",
  92       debug_workingdir, debug_argc);
  93
  94   int32_t* debug_offset = buffer + 1;
  95   for (int debug_i = 0; debug_i < debug_argc; ++debug_i)
  96     printf("  argv[%i]:\t%s\n", debug_i,
  97            ((char*)buffer) + TO_LITTLE_ENDIAN32(debug_offset[debug_i]));
  98 #endif
  99
 100   *aCommandLineLength = bufend - reinterpret_cast<char*>(buffer);
 101   return reinterpret_cast<char*>(buffer);
 102 }