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Diffstat (limited to 'lib/asan/asan_printf.cc')
| -rw-r--r-- | lib/asan/asan_printf.cc | 181 |
1 files changed, 181 insertions, 0 deletions
diff --git a/lib/asan/asan_printf.cc b/lib/asan/asan_printf.cc new file mode 100644 index 000000000000..a3d06ff67ad2 --- /dev/null +++ b/lib/asan/asan_printf.cc @@ -0,0 +1,181 @@ +//===-- 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 |