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llvm-project/compiler-rt/lib/sanitizer_common/sanitizer_printf.cpp

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//===-- sanitizer_printf.cpp ----------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file is shared between AddressSanitizer and ThreadSanitizer.
//
// Internal printf function, used inside run-time libraries.
// We can't use libc printf because we intercept some of the functions used
// inside it.
//===----------------------------------------------------------------------===//
#include "sanitizer_common.h"
#include "sanitizer_flags.h"
#include "sanitizer_libc.h"
#include <stdio.h>
#include <stdarg.h>
#if SANITIZER_WINDOWS && defined(_MSC_VER) && _MSC_VER < 1800 && \
!defined(va_copy)
# define va_copy(dst, src) ((dst) = (src))
#endif
namespace __sanitizer {
static int AppendChar(char **buff, const char *buff_end, char c) {
if (*buff < buff_end) {
**buff = c;
(*buff)++;
}
return 1;
}
// Appends number in a given base to buffer. If its length is less than
// |minimal_num_length|, it is padded with leading zeroes or spaces, depending
// on the value of |pad_with_zero|.
static int AppendNumber(char **buff, const char *buff_end, u64 absolute_value,
u8 base, u8 minimal_num_length, bool pad_with_zero,
bool negative, bool uppercase) {
uptr const kMaxLen = 30;
RAW_CHECK(base == 10 || base == 16);
RAW_CHECK(base == 10 || !negative);
RAW_CHECK(absolute_value || !negative);
RAW_CHECK(minimal_num_length < kMaxLen);
int result = 0;
if (negative && minimal_num_length)
--minimal_num_length;
if (negative && pad_with_zero)
result += AppendChar(buff, buff_end, '-');
uptr num_buffer[kMaxLen];
int pos = 0;
do {
RAW_CHECK_MSG((uptr)pos < kMaxLen, "AppendNumber buffer overflow");
num_buffer[pos++] = absolute_value % base;
absolute_value /= base;
} while (absolute_value > 0);
if (pos < minimal_num_length) {
// Make sure compiler doesn't insert call to memset here.
internal_memset(&num_buffer[pos], 0,
sizeof(num_buffer[0]) * (minimal_num_length - pos));
pos = minimal_num_length;
}
RAW_CHECK(pos > 0);
pos--;
for (; pos >= 0 && num_buffer[pos] == 0; pos--) {
char c = (pad_with_zero || pos == 0) ? '0' : ' ';
result += AppendChar(buff, buff_end, c);
}
if (negative && !pad_with_zero) result += AppendChar(buff, buff_end, '-');
for (; pos >= 0; pos--) {
char digit = static_cast<char>(num_buffer[pos]);
digit = (digit < 10) ? '0' + digit : (uppercase ? 'A' : 'a') + digit - 10;
result += AppendChar(buff, buff_end, digit);
}
return result;
}
static int AppendUnsigned(char **buff, const char *buff_end, u64 num, u8 base,
u8 minimal_num_length, bool pad_with_zero,
bool uppercase) {
return AppendNumber(buff, buff_end, num, base, minimal_num_length,
pad_with_zero, false /* negative */, uppercase);
}
static int AppendSignedDecimal(char **buff, const char *buff_end, s64 num,
u8 minimal_num_length, bool pad_with_zero) {
bool negative = (num < 0);
return AppendNumber(buff, buff_end, (u64)(negative ? -num : num), 10,
minimal_num_length, pad_with_zero, negative,
false /* uppercase */);
}
// Use the fact that explicitly requesting 0 width (%0s) results in UB and
// interpret width == 0 as "no width requested":
// width == 0 - no width requested
// width < 0 - left-justify s within and pad it to -width chars, if necessary
// width > 0 - right-justify s, not implemented yet
static int AppendString(char **buff, const char *buff_end, int width,
int max_chars, const char *s) {
if (!s)
s = "<null>";
int result = 0;
for (; *s; s++) {
if (max_chars >= 0 && result >= max_chars)
break;
result += AppendChar(buff, buff_end, *s);
}
// Only the left justified strings are supported.
while (width < -result)
result += AppendChar(buff, buff_end, ' ');
return result;
}
static int AppendPointer(char **buff, const char *buff_end, u64 ptr_value) {
int result = 0;
result += AppendString(buff, buff_end, 0, -1, "0x");
result += AppendUnsigned(buff, buff_end, ptr_value, 16,
SANITIZER_POINTER_FORMAT_LENGTH,
true /* pad_with_zero */, false /* uppercase */);
return result;
}
int VSNPrintf(char *buff, int buff_length,
const char *format, va_list args) {
static const char *kPrintfFormatsHelp =
"Supported Printf formats: %([0-9]*)?(z|l|ll)?{d,u,x,X}; %p; "
"%[-]([0-9]*)?(\\.\\*)?s; %c\nProvided format: ";
RAW_CHECK(format);
RAW_CHECK(buff_length > 0);
const char *buff_end = &buff[buff_length - 1];
const char *cur = format;
int result = 0;
for (; *cur; cur++) {
if (*cur != '%') {
result += AppendChar(&buff, buff_end, *cur);
continue;
}
cur++;
bool left_justified = *cur == '-';
if (left_justified)
cur++;
bool have_width = (*cur >= '0' && *cur <= '9');
bool pad_with_zero = (*cur == '0');
int width = 0;
if (have_width) {
while (*cur >= '0' && *cur <= '9') {
width = width * 10 + *cur++ - '0';
}
}
bool have_precision = (cur[0] == '.' && cur[1] == '*');
int precision = -1;
if (have_precision) {
cur += 2;
precision = va_arg(args, int);
}
bool have_z = (*cur == 'z');
cur += have_z;
bool have_l = cur[0] == 'l' && cur[1] != 'l';
cur += have_l;
bool have_ll = cur[0] == 'l' && cur[1] == 'l';
cur += have_ll * 2;
const bool have_length = have_z || have_l || have_ll;
const bool have_flags = have_width || have_length;
// At the moment only %s supports precision and left-justification.
CHECK(!((precision >= 0 || left_justified) && *cur != 's'));
switch (*cur) {
case 'd': {
s64 dval = have_ll ? va_arg(args, s64)
: have_z ? va_arg(args, sptr)
: have_l ? va_arg(args, long)
: va_arg(args, int);
result += AppendSignedDecimal(&buff, buff_end, dval, width,
pad_with_zero);
break;
}
case 'u':
case 'x':
case 'X': {
u64 uval = have_ll ? va_arg(args, u64)
: have_z ? va_arg(args, uptr)
: have_l ? va_arg(args, unsigned long)
: va_arg(args, unsigned);
bool uppercase = (*cur == 'X');
result += AppendUnsigned(&buff, buff_end, uval, (*cur == 'u') ? 10 : 16,
width, pad_with_zero, uppercase);
break;
}
case 'p': {
RAW_CHECK_VA(!have_flags, kPrintfFormatsHelp, format);
result += AppendPointer(&buff, buff_end, va_arg(args, uptr));
break;
}
case 's': {
RAW_CHECK_VA(!have_length, kPrintfFormatsHelp, format);
// Only left-justified width is supported.
CHECK(!have_width || left_justified);
result += AppendString(&buff, buff_end, left_justified ? -width : width,
precision, va_arg(args, char*));
break;
}
case 'c': {
RAW_CHECK_VA(!have_flags, kPrintfFormatsHelp, format);
result += AppendChar(&buff, buff_end, va_arg(args, int));
break;
}
case '%' : {
RAW_CHECK_VA(!have_flags, kPrintfFormatsHelp, format);
result += AppendChar(&buff, buff_end, '%');
break;
}
default: {
RAW_CHECK_VA(false, kPrintfFormatsHelp, format);
}
}
}
RAW_CHECK(buff <= buff_end);
AppendChar(&buff, buff_end + 1, '\0');
return result;
}
static void (*PrintfAndReportCallback)(const char *);
void SetPrintfAndReportCallback(void (*callback)(const char *)) {
PrintfAndReportCallback = callback;
}
// Can be overriden in frontend.
#if SANITIZER_GO && defined(TSAN_EXTERNAL_HOOKS)
// Implementation must be defined in frontend.
extern "C" void __sanitizer_on_print(const char *str);
#else
SANITIZER_INTERFACE_WEAK_DEF(void, __sanitizer_on_print, const char *str) {
(void)str;
}
#endif
static void CallPrintfAndReportCallback(const char *str) {
__sanitizer_on_print(str);
if (PrintfAndReportCallback)
PrintfAndReportCallback(str);
}
static void NOINLINE SharedPrintfCodeNoBuffer(bool append_pid,
char *local_buffer,
int buffer_size,
const char *format,
va_list args) {
va_list args2;
va_copy(args2, args);
InternalMmapVector<char> v;
int needed_length = 0;
char *buffer = local_buffer;
// First try to print a message using a local buffer, and then fall back to
// mmaped buffer.
for (int use_mmap = 0;; use_mmap++) {
if (use_mmap) {
va_end(args);
va_copy(args, args2);
v.resize(needed_length + 1);
buffer_size = v.capacity();
v.resize(buffer_size);
buffer = &v[0];
}
needed_length = 0;
// Fuchsia's logging infrastructure always keeps track of the logging
// process, thread, and timestamp, so never prepend such information.
if (!SANITIZER_FUCHSIA && append_pid) {
int pid = internal_getpid();
const char *exe_name = GetProcessName();
if (common_flags()->log_exe_name && exe_name) {
needed_length += internal_snprintf(buffer, buffer_size,
"==%s", exe_name);
if (needed_length >= buffer_size)
continue;
}
needed_length += internal_snprintf(
buffer + needed_length, buffer_size - needed_length, "==%d==", pid);
if (needed_length >= buffer_size)
continue;
}
needed_length += VSNPrintf(buffer + needed_length,
buffer_size - needed_length, format, args);
if (needed_length >= buffer_size)
continue;
// If the message fit into the buffer, print it and exit.
break;
}
RawWrite(buffer);
// Remove color sequences from the message.
RemoveANSIEscapeSequencesFromString(buffer);
CallPrintfAndReportCallback(buffer);
LogMessageOnPrintf(buffer);
va_end(args2);
}
static void NOINLINE SharedPrintfCode(bool append_pid, const char *format,
va_list args) {
// |local_buffer| is small enough not to overflow the stack and/or violate
// the stack limit enforced by TSan (-Wframe-larger-than=512). On the other
// hand, the bigger the buffer is, the more the chance the error report will
// fit into it.
char local_buffer[400];
SharedPrintfCodeNoBuffer(append_pid, local_buffer, ARRAY_SIZE(local_buffer),
format, args);
}
void Printf(const char *format, ...) {
va_list args;
va_start(args, format);
SharedPrintfCode(false, format, args);
va_end(args);
}
// Like Printf, but prints the current PID before the output string.
void Report(const char *format, ...) {
va_list args;
va_start(args, format);
SharedPrintfCode(true, format, args);
va_end(args);
}
// Writes at most "length" symbols to "buffer" (including trailing '\0').
// Returns the number of symbols that should have been written to buffer
// (not including trailing '\0'). Thus, the string is truncated
// iff return value is not less than "length".
int internal_snprintf(char *buffer, uptr length, const char *format, ...) {
va_list args;
va_start(args, format);
int needed_length = VSNPrintf(buffer, length, format, args);
va_end(args);
return needed_length;
}
void InternalScopedString::append(const char *format, ...) {
uptr prev_len = length();
while (true) {
buffer_.resize(buffer_.capacity());
va_list args;
va_start(args, format);
uptr sz = VSNPrintf(buffer_.data() + prev_len, buffer_.size() - prev_len,
format, args);
va_end(args);
if (sz < buffer_.size() - prev_len) {
buffer_.resize(prev_len + sz + 1);
break;
}
buffer_.reserve(buffer_.capacity() * 2);
}
CHECK_EQ(buffer_[length()], '\0');
}
} // namespace __sanitizer
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