compiler-rt/lib/xray/xray_utils.cpp

   1 //===-- xray_utils.cpp ------------------------------------------*- C++ -*-===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 //
   9 // This file is a part of XRay, a dynamic runtime instrumentation system.
  10 //
  11 //===----------------------------------------------------------------------===//
  12 #include "xray_utils.h"
  13
  14 #include "sanitizer_common/sanitizer_allocator_internal.h"
  15 #include "sanitizer_common/sanitizer_common.h"
  16 #include "xray_allocator.h"
  17 #include "xray_defs.h"
  18 #include "xray_flags.h"
  19 #include <cstdio>
  20 #include <errno.h>
  21 #include <fcntl.h>
  22 #include <iterator>
  23 #include <stdlib.h>
  24 #include <sys/types.h>
  25 #include <tuple>
  26 #include <unistd.h>
  27 #include <utility>
  28
  29 #if SANITIZER_FUCHSIA
  30 #include "sanitizer_common/sanitizer_symbolizer_fuchsia.h"
  31
  32 #include <inttypes.h>
  33 #include <zircon/process.h>
  34 #include <zircon/sanitizer.h>
  35 #include <zircon/status.h>
  36 #include <zircon/syscalls.h>
  37 #endif
  38
  39 namespace __xray {
  40
  41 #if SANITIZER_FUCHSIA
  42 constexpr const char* ProfileSinkName = "llvm-xray";
  43
  44 LogWriter::~LogWriter() {
  45   _zx_handle_close(Vmo);
  46 }
  47
  48 void LogWriter::WriteAll(const char *Begin, const char *End) XRAY_NEVER_INSTRUMENT {
  49   if (Begin == End)
  50     return;
  51   auto TotalBytes = std::distance(Begin, End);
  52
  53   const size_t PageSize = flags()->xray_page_size_override > 0
  54                               ? flags()->xray_page_size_override
  55                               : GetPageSizeCached();
  56   if (RoundUpTo(Offset, PageSize) != RoundUpTo(Offset + TotalBytes, PageSize)) {
  57     // Resize the VMO to ensure there's sufficient space for the data.
  58     zx_status_t Status = _zx_vmo_set_size(Vmo, Offset + TotalBytes);
  59     if (Status != ZX_OK) {
  60       Report("Failed to resize VMO: %s\n", _zx_status_get_string(Status));
  61       return;
  62     }
  63   }
  64
  65   // Write the data into VMO.
  66   zx_status_t Status = _zx_vmo_write(Vmo, Begin, Offset, TotalBytes);
  67   if (Status != ZX_OK) {
  68     Report("Failed to write: %s\n", _zx_status_get_string(Status));
  69     return;
  70   }
  71   Offset += TotalBytes;
  72 }
  73
  74 void LogWriter::Flush() XRAY_NEVER_INSTRUMENT {
  75   // Nothing to do here since WriteAll writes directly into the VMO.
  76 }
  77
  78 LogWriter *LogWriter::Open() XRAY_NEVER_INSTRUMENT {
  79   // Create VMO to hold the profile data.
  80   zx_handle_t Vmo;
  81   zx_status_t Status = _zx_vmo_create(0, ZX_VMO_RESIZABLE, &Vmo);
  82   if (Status != ZX_OK) {
  83     Report("XRay: cannot create VMO: %s\n", _zx_status_get_string(Status));
  84     return nullptr;
  85   }
  86
  87   // Get the KOID of the current process to use in the VMO name.
  88   zx_info_handle_basic_t Info;
  89   Status = _zx_object_get_info(_zx_process_self(), ZX_INFO_HANDLE_BASIC, &Info,
  90                                sizeof(Info), NULL, NULL);
  91   if (Status != ZX_OK) {
  92     Report("XRay: cannot get basic info about current process handle: %s\n",
  93            _zx_status_get_string(Status));
  94     return nullptr;
  95   }
  96
  97   // Give the VMO a name including our process KOID so it's easy to spot.
  98   char VmoName[ZX_MAX_NAME_LEN];
  99   internal_snprintf(VmoName, sizeof(VmoName), "%s.%zu", ProfileSinkName,
 100                     Info.koid);
 101   _zx_object_set_property(Vmo, ZX_PROP_NAME, VmoName, strlen(VmoName));
 102
 103   // Duplicate the handle since __sanitizer_publish_data consumes it and
 104   // LogWriter needs to hold onto it.
 105   zx_handle_t Handle;
 106   Status =_zx_handle_duplicate(Vmo, ZX_RIGHT_SAME_RIGHTS, &Handle);
 107   if (Status != ZX_OK) {
 108     Report("XRay: cannot duplicate VMO handle: %s\n",
 109            _zx_status_get_string(Status));
 110     return nullptr;
 111   }
 112
 113   // Publish the VMO that receives the logging. Note the VMO's contents can
 114   // grow and change after publication. The contents won't be read out until
 115   // after the process exits.
 116   __sanitizer_publish_data(ProfileSinkName, Handle);
 117
 118   // Use the dumpfile symbolizer markup element to write the name of the VMO.
 119   Report("XRay: " FORMAT_DUMPFILE "\n", ProfileSinkName, VmoName);
 120
 121   LogWriter *LW = reinterpret_cast<LogWriter *>(InternalAlloc(sizeof(LogWriter)));
 122   new (LW) LogWriter(Vmo);
 123   return LW;
 124 }
 125
 126 void LogWriter::Close(LogWriter *LW) {
 127   LW->~LogWriter();
 128   InternalFree(LW);
 129 }
 130 #else // SANITIZER_FUCHSIA
 131 LogWriter::~LogWriter() {
 132   internal_close(Fd);
 133 }
 134
 135 void LogWriter::WriteAll(const char *Begin, const char *End) XRAY_NEVER_INSTRUMENT {
 136   if (Begin == End)
 137     return;
 138   auto TotalBytes = std::distance(Begin, End);
 139   while (auto Written = write(Fd, Begin, TotalBytes)) {
 140     if (Written < 0) {
 141       if (errno == EINTR)
 142         continue; // Try again.
 143       Report("Failed to write; errno = %d\n", errno);
 144       return;
 145     }
 146     TotalBytes -= Written;
 147     if (TotalBytes == 0)
 148       break;
 149     Begin += Written;
 150   }
 151 }
 152
 153 void LogWriter::Flush() XRAY_NEVER_INSTRUMENT {
 154   fsync(Fd);
 155 }
 156
 157 LogWriter *LogWriter::Open() XRAY_NEVER_INSTRUMENT {
 158   // Open a temporary file once for the log.
 159   char TmpFilename[256] = {};
 160   char TmpWildcardPattern[] = "XXXXXX";
 161   auto **Argv = GetArgv();
 162   const char *Progname = !Argv ? "(unknown)" : Argv[0];
 163   const char *LastSlash = internal_strrchr(Progname, '/');
 164
 165   if (LastSlash != nullptr)
 166     Progname = LastSlash + 1;
 167
 168   int NeededLength = internal_snprintf(
 169       TmpFilename, sizeof(TmpFilename), "%s%s.%s",
 170       flags()->xray_logfile_base, Progname, TmpWildcardPattern);
 171   if (NeededLength > int(sizeof(TmpFilename))) {
 172     Report("XRay log file name too long (%d): %s\n", NeededLength, TmpFilename);
 173     return nullptr;
 174   }
 175   int Fd = mkstemp(TmpFilename);
 176   if (Fd == -1) {
 177     Report("XRay: Failed opening temporary file '%s'; not logging events.\n",
 178            TmpFilename);
 179     return nullptr;
 180   }
 181   if (Verbosity())
 182     Report("XRay: Log file in '%s'\n", TmpFilename);
 183
 184   LogWriter *LW = allocate<LogWriter>();
 185   new (LW) LogWriter(Fd);
 186   return LW;
 187 }
 188
 189 void LogWriter::Close(LogWriter *LW) {
 190   LW->~LogWriter();
 191   deallocate(LW);
 192 }
 193 #endif // SANITIZER_FUCHSIA
 194
 195 } // namespace __xray