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//===-- asan_printf.cc ------------------------------------------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file is a part of AddressSanitizer, an address sanity checker.
//
// Internal printf function, used inside ASan run-time library.
// We can't use libc printf because we intercept some of the functions used
// inside it.
//===----------------------------------------------------------------------===//
#include "asan_internal.h"
#include "asan_interceptors.h"
#include <stdarg.h>
namespace __asan {
void RawWrite(const char *buffer) {
static const char *kRawWriteError = "RawWrite can't output requested buffer!";
ssize_t length = (ssize_t)internal_strlen(buffer);
if (length != AsanWrite(2, buffer, length)) {
AsanWrite(2, kRawWriteError, internal_strlen(kRawWriteError));
ASAN_DIE;
}
}
static inline 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.
static int AppendUnsigned(char **buff, const char *buff_end, uint64_t num,
uint8_t base, uint8_t minimal_num_length) {
size_t const kMaxLen = 30;
RAW_CHECK(base == 10 || base == 16);
RAW_CHECK(minimal_num_length < kMaxLen);
size_t num_buffer[kMaxLen];
size_t pos = 0;
do {
RAW_CHECK_MSG(pos < kMaxLen, "appendNumber buffer overflow");
num_buffer[pos++] = num % base;
num /= base;
} while (num > 0);
while (pos < minimal_num_length) num_buffer[pos++] = 0;
int result = 0;
while (pos-- > 0) {
size_t digit = num_buffer[pos];
result += AppendChar(buff, buff_end, (digit < 10) ? '0' + digit
: 'a' + digit - 10);
}
return result;
}
static inline int AppendSignedDecimal(char **buff, const char *buff_end,
int64_t num) {
int result = 0;
if (num < 0) {
result += AppendChar(buff, buff_end, '-');
num = -num;
}
result += AppendUnsigned(buff, buff_end, (uint64_t)num, 10, 0);
return result;
}
static inline int AppendString(char **buff, const char *buff_end,
const char *s) {
// Avoid library functions like stpcpy here.
RAW_CHECK(s);
int result = 0;
for (; *s; s++) {
result += AppendChar(buff, buff_end, *s);
}
return result;
}
static inline int AppendPointer(char **buff, const char *buff_end,
uint64_t ptr_value) {
int result = 0;
result += AppendString(buff, buff_end, "0x");
result += AppendUnsigned(buff, buff_end, ptr_value, 16,
(__WORDSIZE == 64) ? 12 : 8);
return result;
}
static int VSNPrintf(char *buff, int buff_length,
const char *format, va_list args) {
static const char *kPrintfFormatsHelp = "Supported Printf formats: "
"%%[l]{d,u,x}; %%p; %%s";
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 == '%') {
cur++;
bool have_l = (*cur == 'l');
cur += have_l;
int64_t dval;
uint64_t uval, xval;
switch (*cur) {
case 'd': dval = have_l ? va_arg(args, intptr_t)
: va_arg(args, int);
result += AppendSignedDecimal(&buff, buff_end, dval);
break;
case 'u': uval = have_l ? va_arg(args, uintptr_t)
: va_arg(args, unsigned int);
result += AppendUnsigned(&buff, buff_end, uval, 10, 0);
break;
case 'x': xval = have_l ? va_arg(args, uintptr_t)
: va_arg(args, unsigned int);
result += AppendUnsigned(&buff, buff_end, xval, 16, 0);
break;
case 'p': RAW_CHECK_MSG(!have_l, kPrintfFormatsHelp);
result += AppendPointer(&buff, buff_end,
va_arg(args, uintptr_t));
break;
case 's': RAW_CHECK_MSG(!have_l, kPrintfFormatsHelp);
result += AppendString(&buff, buff_end, va_arg(args, char*));
break;
default: RAW_CHECK_MSG(false, kPrintfFormatsHelp);
}
} else {
result += AppendChar(&buff, buff_end, *cur);
}
}
RAW_CHECK(buff <= buff_end);
AppendChar(&buff, buff_end + 1, '\0');
return result;
}
void Printf(const char *format, ...) {
const int kLen = 1024 * 4;
char buffer[kLen];
va_list args;
va_start(args, format);
int needed_length = VSNPrintf(buffer, kLen, format, args);
va_end(args);
RAW_CHECK_MSG(needed_length < kLen, "Buffer in Printf is too short!\n");
RawWrite(buffer);
}
// 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 SNPrintf(char *buffer, size_t 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;
}
// Like Printf, but prints the current PID before the output string.
void Report(const char *format, ...) {
const int kLen = 1024 * 4;
char buffer[kLen];
int needed_length = SNPrintf(buffer, kLen, "==%d== ", getpid());
RAW_CHECK_MSG(needed_length < kLen, "Buffer in Report is too short!\n");
va_list args;
va_start(args, format);
needed_length += VSNPrintf(buffer + needed_length, kLen - needed_length,
format, args);
va_end(args);
RAW_CHECK_MSG(needed_length < kLen, "Buffer in Report is too short!\n");
RawWrite(buffer);
}
} // namespace __asan
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