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 <new>
24#include <stdlib.h>
25#include <sys/types.h>
26#include <tuple>
27#include <unistd.h>
28#include <utility>
29
30#if SANITIZER_FUCHSIA
31#include "sanitizer_common/sanitizer_symbolizer_markup_constants.h"
32
33#include <inttypes.h>
34#include <zircon/process.h>
35#include <zircon/sanitizer.h>
36#include <zircon/status.h>
37#include <zircon/syscalls.h>
38#endif
39
40namespace __xray {
41
42#if SANITIZER_FUCHSIA
43constexpr const char* ProfileSinkName = "llvm-xray";
44
45LogWriter::~LogWriter() {
46 _zx_handle_close(Vmo);
47}
48
49void LogWriter::WriteAll(const char *Begin, const char *End) XRAY_NEVER_INSTRUMENT {
50 if (Begin == End)
51 return;
52 auto TotalBytes = std::distance(Begin, End);
53
54 const size_t PageSize = flags()->xray_page_size_override > 0
55 ? flags()->xray_page_size_override
56 : GetPageSizeCached();
57 if (RoundUpTo(Offset, PageSize) != RoundUpTo(Offset + TotalBytes, PageSize)) {
58 // Resize the VMO to ensure there's sufficient space for the data.
59 zx_status_t Status = _zx_vmo_set_size(Vmo, Offset + TotalBytes);
60 if (Status != ZX_OK) {
61 Report("Failed to resize VMO: %s\n", _zx_status_get_string(Status));
62 return;
63 }
64 }
65
66 // Write the data into VMO.
67 zx_status_t Status = _zx_vmo_write(Vmo, Begin, Offset, TotalBytes);
68 if (Status != ZX_OK) {
69 Report("Failed to write: %s\n", _zx_status_get_string(Status));
70 return;
71 }
72 Offset += TotalBytes;
73
74 // Record the data size as a property of the VMO.
75 _zx_object_set_property(Vmo, ZX_PROP_VMO_CONTENT_SIZE,
76 &Offset, sizeof(Offset));
77}
78
79void LogWriter::Flush() XRAY_NEVER_INSTRUMENT {
80 // Nothing to do here since WriteAll writes directly into the VMO.
81}
82
83LogWriter *LogWriter::Open() XRAY_NEVER_INSTRUMENT {
84 // Create VMO to hold the profile data.
85 zx_handle_t Vmo;
86 zx_status_t Status = _zx_vmo_create(0, ZX_VMO_RESIZABLE, &Vmo);
87 if (Status != ZX_OK) {
88 Report("XRay: cannot create VMO: %s\n", _zx_status_get_string(Status));
89 return nullptr;
90 }
91
92 // Get the KOID of the current process to use in the VMO name.
93 zx_info_handle_basic_t Info;
94 Status = _zx_object_get_info(_zx_process_self(), ZX_INFO_HANDLE_BASIC, &Info,
95 sizeof(Info), NULL, NULL);
96 if (Status != ZX_OK) {
97 Report("XRay: cannot get basic info about current process handle: %s\n",
98 _zx_status_get_string(Status));
99 return nullptr;
100 }
101
102 // Give the VMO a name including our process KOID so it's easy to spot.
103 char VmoName[ZX_MAX_NAME_LEN];
104 internal_snprintf(VmoName, sizeof(VmoName), "%s.%zu", ProfileSinkName,
105 Info.koid);
106 _zx_object_set_property(Vmo, ZX_PROP_NAME, VmoName, strlen(VmoName));
107
108 // Duplicate the handle since __sanitizer_publish_data consumes it and
109 // LogWriter needs to hold onto it.
110 zx_handle_t Handle;
111 Status =_zx_handle_duplicate(Vmo, ZX_RIGHT_SAME_RIGHTS, &Handle);
112 if (Status != ZX_OK) {
113 Report("XRay: cannot duplicate VMO handle: %s\n",
114 _zx_status_get_string(Status));
115 return nullptr;
116 }
117
118 // Publish the VMO that receives the logging. Note the VMO's contents can
119 // grow and change after publication. The contents won't be read out until
120 // after the process exits.
121 __sanitizer_publish_data(ProfileSinkName, Handle);
122
123 // Use the dumpfile symbolizer markup element to write the name of the VMO.
124 Report("XRay: " FORMAT_DUMPFILE "\n", ProfileSinkName, VmoName);
125
126 LogWriter *LW = reinterpret_cast<LogWriter *>(InternalAlloc(sizeof(LogWriter)));
127 new (LW) LogWriter(Vmo);
128 return LW;
129}
130
131void LogWriter::Close(LogWriter *LW) {
132 LW->~LogWriter();
133 InternalFree(LW);
134}
135#else // SANITIZER_FUCHSIA
136LogWriter::~LogWriter() {
137 internal_close(fd: Fd);
138}
139
140void LogWriter::WriteAll(const char *Begin, const char *End) XRAY_NEVER_INSTRUMENT {
141 if (Begin == End)
142 return;
143 auto TotalBytes = std::distance(first: Begin, last: End);
144 while (auto Written = write(fd: Fd, buf: Begin, n: TotalBytes)) {
145 if (Written < 0) {
146 if (errno == EINTR)
147 continue; // Try again.
148 Report(format: "Failed to write; errno = %d\n", errno);
149 return;
150 }
151 TotalBytes -= Written;
152 if (TotalBytes == 0)
153 break;
154 Begin += Written;
155 }
156}
157
158void LogWriter::Flush() XRAY_NEVER_INSTRUMENT {
159 fsync(fd: Fd);
160}
161
162LogWriter *LogWriter::Open() XRAY_NEVER_INSTRUMENT {
163 // Open a temporary file once for the log.
164 char TmpFilename[256] = {};
165 char TmpWildcardPattern[] = "XXXXXX";
166 auto **Argv = GetArgv();
167 const char *Progname = !Argv ? "(unknown)" : Argv[0];
168 const char *LastSlash = internal_strrchr(s: Progname, c: '/');
169
170 if (LastSlash != nullptr)
171 Progname = LastSlash + 1;
172
173 int NeededLength = internal_snprintf(
174 buffer: TmpFilename, length: sizeof(TmpFilename), format: "%s%s.%s",
175 flags()->xray_logfile_base, Progname, TmpWildcardPattern);
176 if (NeededLength > int(sizeof(TmpFilename))) {
177 Report(format: "XRay log file name too long (%d): %s\n", NeededLength, TmpFilename);
178 return nullptr;
179 }
180 int Fd = mkstemp(template: TmpFilename);
181 if (Fd == -1) {
182 Report(format: "XRay: Failed opening temporary file '%s'; not logging events.\n",
183 TmpFilename);
184 return nullptr;
185 }
186 if (Verbosity())
187 Report(format: "XRay: Log file in '%s'\n", TmpFilename);
188
189 LogWriter *LW = allocate<LogWriter>();
190 new (LW) LogWriter(Fd);
191 return LW;
192}
193
194void LogWriter::Close(LogWriter *LW) {
195 LW->~LogWriter();
196 deallocate(B: LW);
197}
198#endif // SANITIZER_FUCHSIA
199
200} // namespace __xray
201