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 <strings.h>
  12 #include <unistd.h>
  13 #include <limits.h>
  14
  15 #include "RemoteUtils.h"
  16
  17 #ifdef IS_BIG_ENDIAN
  18 #  define TO_LITTLE_ENDIAN32(x)                           \
  19     ((((x)&0xff000000) >> 24) | (((x)&0x00ff0000) >> 8) | \
  20      (((x)&0x0000ff00) << 8) | (((x)&0x000000ff) << 24))
  21 #else
  22 #  define TO_LITTLE_ENDIAN32(x) (x)
  23 #endif
  24
  25 #ifndef MAX_PATH
  26 #  ifdef PATH_MAX
  27 #    define MAX_PATH PATH_MAX
  28 #  else
  29 #    define MAX_PATH 1024
  30 #  endif
  31 #endif
  32
  33 /* like strcpy, but return the char after the final null */
  34 static char* estrcpy(const char* s, char* d) {
  35   while (*s) *d++ = *s++;
  36
  37   *d++ = '\0';
  38   return d;
  39 }
  40
  41 /* Construct a command line from given args and desktop startup ID.
  42  * Returned buffer must be released by free().
  43  */
  44 char* ConstructCommandLine(int32_t argc, char** argv,
  45                            const char* aDesktopStartupID,
  46                            int* aCommandLineLength) {
  47   char cwdbuf[MAX_PATH];
  48   if (!getcwd(cwdbuf, MAX_PATH)) return nullptr;
  49
  50   // the commandline property is constructed as an array of int32_t
  51   // followed by a series of null-terminated strings:
  52   //
  53   // [argc][offsetargv0][offsetargv1...]<workingdir>\0<argv[0]>\0argv[1]...\0
  54   // (offset is from the beginning of the buffer)
  55
  56   static char desktopStartupPrefix[] = " DESKTOP_STARTUP_ID=";
  57
  58   int32_t argvlen = strlen(cwdbuf);
  59   for (int i = 0; i < argc; ++i) {
  60     int32_t len = strlen(argv[i]);
  61     if (i == 0 && aDesktopStartupID) {
  62       len += sizeof(desktopStartupPrefix) - 1 + strlen(aDesktopStartupID);
  63     }
  64     argvlen += len;
  65   }
  66
  67   auto* buffer =
  68       (int32_t*)malloc(argvlen + argc + 1 + sizeof(int32_t) * (argc + 1));
  69   if (!buffer) return nullptr;
  70
  71   buffer[0] = TO_LITTLE_ENDIAN32(argc);
  72
  73   auto* bufend = (char*)(buffer + argc + 1);
  74
  75   bufend = estrcpy(cwdbuf, bufend);
  76
  77   for (int i = 0; i < argc; ++i) {
  78     buffer[i + 1] = TO_LITTLE_ENDIAN32(bufend - ((char*)buffer));
  79     bufend = estrcpy(argv[i], bufend);
  80     if (i == 0 && aDesktopStartupID) {
  81       bufend = estrcpy(desktopStartupPrefix, bufend - 1);
  82       bufend = estrcpy(aDesktopStartupID, bufend - 1);
  83     }
  84   }
  85
  86 #ifdef DEBUG_command_line
  87   int32_t debug_argc = TO_LITTLE_ENDIAN32(*buffer);
  88   char* debug_workingdir = (char*)(buffer + argc + 1);
  89
  90   printf(
  91       "Sending command line:\n"
  92       "  working dir: %s\n"
  93       "  argc:\t%i",
  94       debug_workingdir, debug_argc);
  95
  96   int32_t* debug_offset = buffer + 1;
  97   for (int debug_i = 0; debug_i < debug_argc; ++debug_i)
  98     printf("  argv[%i]:\t%s\n", debug_i,
  99            ((char*)buffer) + TO_LITTLE_ENDIAN32(debug_offset[debug_i]));
 100 #endif
 101
 102   *aCommandLineLength = bufend - reinterpret_cast<char*>(buffer);
 103   return reinterpret_cast<char*>(buffer);
 104 }