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//===-- string_utils.cpp ----------------------------------------*- C++ -*-===//
//
// 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
//
//===----------------------------------------------------------------------===//
#include "string_utils.h"
#include "common.h"
#include <stdarg.h>
#include <string.h>
namespace scudo {
static int appendChar(char **Buffer, const char *BufferEnd, char C) {
if (*Buffer < BufferEnd) {
**Buffer = C;
(*Buffer)++;
}
return 1;
}
// Appends number in a given Base to buffer. If its length is less than
// |MinNumberLength|, it is padded with leading zeroes or spaces, depending
// on the value of |PadWithZero|.
static int appendNumber(char **Buffer, const char *BufferEnd, u64 AbsoluteValue,
u8 Base, u8 MinNumberLength, bool PadWithZero,
bool Negative, bool Upper) {
constexpr uptr MaxLen = 30;
RAW_CHECK(Base == 10 || Base == 16);
RAW_CHECK(Base == 10 || !Negative);
RAW_CHECK(AbsoluteValue || !Negative);
RAW_CHECK(MinNumberLength < MaxLen);
int Res = 0;
if (Negative && MinNumberLength)
--MinNumberLength;
if (Negative && PadWithZero)
Res += appendChar(Buffer, BufferEnd, '-');
uptr NumBuffer[MaxLen];
int Pos = 0;
do {
RAW_CHECK_MSG(static_cast<uptr>(Pos) < MaxLen,
"appendNumber buffer overflow");
NumBuffer[Pos++] = static_cast<uptr>(AbsoluteValue % Base);
AbsoluteValue /= Base;
} while (AbsoluteValue > 0);
if (Pos < MinNumberLength) {
memset(&NumBuffer[Pos], 0,
sizeof(NumBuffer[0]) * static_cast<uptr>(MinNumberLength - Pos));
Pos = MinNumberLength;
}
RAW_CHECK(Pos > 0);
Pos--;
for (; Pos >= 0 && NumBuffer[Pos] == 0; Pos--) {
char c = (PadWithZero || Pos == 0) ? '0' : ' ';
Res += appendChar(Buffer, BufferEnd, c);
}
if (Negative && !PadWithZero)
Res += appendChar(Buffer, BufferEnd, '-');
for (; Pos >= 0; Pos--) {
char Digit = static_cast<char>(NumBuffer[Pos]);
Digit = static_cast<char>((Digit < 10) ? '0' + Digit
: (Upper ? 'A' : 'a') + Digit - 10);
Res += appendChar(Buffer, BufferEnd, Digit);
}
return Res;
}
static int appendUnsigned(char **Buffer, const char *BufferEnd, u64 Num,
u8 Base, u8 MinNumberLength, bool PadWithZero,
bool Upper) {
return appendNumber(Buffer, BufferEnd, Num, Base, MinNumberLength,
PadWithZero, /*Negative=*/false, Upper);
}
static int appendSignedDecimal(char **Buffer, const char *BufferEnd, s64 Num,
u8 MinNumberLength, bool PadWithZero) {
const bool Negative = (Num < 0);
const u64 UnsignedNum = (Num == INT64_MIN)
? static_cast<u64>(INT64_MAX) + 1
: static_cast<u64>(Negative ? -Num : Num);
return appendNumber(Buffer, BufferEnd, UnsignedNum, 10, MinNumberLength,
PadWithZero, Negative, /*Upper=*/false);
}
// 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 **Buffer, const char *BufferEnd, int Width,
int MaxChars, const char *S) {
if (!S)
S = "<null>";
int Res = 0;
for (; *S; S++) {
if (MaxChars >= 0 && Res >= MaxChars)
break;
Res += appendChar(Buffer, BufferEnd, *S);
}
// Only the left justified strings are supported.
while (Width < -Res)
Res += appendChar(Buffer, BufferEnd, ' ');
return Res;
}
static int appendPointer(char **Buffer, const char *BufferEnd, u64 ptr_value) {
int Res = 0;
Res += appendString(Buffer, BufferEnd, 0, -1, "0x");
Res += appendUnsigned(Buffer, BufferEnd, ptr_value, 16,
SCUDO_POINTER_FORMAT_LENGTH, /*PadWithZero=*/true,
/*Upper=*/false);
return Res;
}
static int formatString(char *Buffer, uptr BufferLength, const char *Format,
va_list Args) {
static const char *PrintfFormatsHelp =
"Supported formatString formats: %([0-9]*)?(z|ll)?{d,u,x,X}; %p; "
"%[-]([0-9]*)?(\\.\\*)?s; %c\n";
RAW_CHECK(Format);
RAW_CHECK(BufferLength > 0);
const char *BufferEnd = &Buffer[BufferLength - 1];
const char *Cur = Format;
int Res = 0;
for (; *Cur; Cur++) {
if (*Cur != '%') {
Res += appendChar(&Buffer, BufferEnd, *Cur);
continue;
}
Cur++;
const bool LeftJustified = *Cur == '-';
if (LeftJustified)
Cur++;
bool HaveWidth = (*Cur >= '0' && *Cur <= '9');
const bool PadWithZero = (*Cur == '0');
u8 Width = 0;
if (HaveWidth) {
while (*Cur >= '0' && *Cur <= '9')
Width = static_cast<u8>(Width * 10 + *Cur++ - '0');
}
const bool HavePrecision = (Cur[0] == '.' && Cur[1] == '*');
int Precision = -1;
if (HavePrecision) {
Cur += 2;
Precision = va_arg(Args, int);
}
const bool HaveZ = (*Cur == 'z');
Cur += HaveZ;
const bool HaveLL = !HaveZ && (Cur[0] == 'l' && Cur[1] == 'l');
Cur += HaveLL * 2;
s64 DVal;
u64 UVal;
const bool HaveLength = HaveZ || HaveLL;
const bool HaveFlags = HaveWidth || HaveLength;
// At the moment only %s supports precision and left-justification.
CHECK(!((Precision >= 0 || LeftJustified) && *Cur != 's'));
switch (*Cur) {
case 'd': {
DVal = HaveLL ? va_arg(Args, s64)
: HaveZ ? va_arg(Args, sptr)
: va_arg(Args, int);
Res += appendSignedDecimal(&Buffer, BufferEnd, DVal, Width, PadWithZero);
break;
}
case 'u':
case 'x':
case 'X': {
UVal = HaveLL ? va_arg(Args, u64)
: HaveZ ? va_arg(Args, uptr)
: va_arg(Args, unsigned);
const bool Upper = (*Cur == 'X');
Res += appendUnsigned(&Buffer, BufferEnd, UVal, (*Cur == 'u') ? 10 : 16,
Width, PadWithZero, Upper);
break;
}
case 'p': {
RAW_CHECK_MSG(!HaveFlags, PrintfFormatsHelp);
Res += appendPointer(&Buffer, BufferEnd, va_arg(Args, uptr));
break;
}
case 's': {
RAW_CHECK_MSG(!HaveLength, PrintfFormatsHelp);
// Only left-justified Width is supported.
CHECK(!HaveWidth || LeftJustified);
Res += appendString(&Buffer, BufferEnd, LeftJustified ? -Width : Width,
Precision, va_arg(Args, char *));
break;
}
case 'c': {
RAW_CHECK_MSG(!HaveFlags, PrintfFormatsHelp);
Res +=
appendChar(&Buffer, BufferEnd, static_cast<char>(va_arg(Args, int)));
break;
}
// In Scudo, `s64`/`u64` are supposed to use `lld` and `llu` respectively.
// However, `-Wformat` doesn't know we have a different parser for those
// placeholders and it keeps complaining the type mismatch on 64-bit
// platform which uses `ld`/`lu` for `s64`/`u64`. Therefore, in order to
// silence the warning, we turn to use `PRId64`/`PRIu64` for printing
// `s64`/`u64` and handle the `ld`/`lu` here.
case 'l': {
++Cur;
RAW_CHECK(*Cur == 'd' || *Cur == 'u');
if (*Cur == 'd') {
DVal = va_arg(Args, s64);
Res +=
appendSignedDecimal(&Buffer, BufferEnd, DVal, Width, PadWithZero);
} else {
UVal = va_arg(Args, u64);
Res += appendUnsigned(&Buffer, BufferEnd, UVal, 10, Width, PadWithZero,
false);
}
break;
}
case '%': {
RAW_CHECK_MSG(!HaveFlags, PrintfFormatsHelp);
Res += appendChar(&Buffer, BufferEnd, '%');
break;
}
default: {
RAW_CHECK_MSG(false, PrintfFormatsHelp);
}
}
}
RAW_CHECK(Buffer <= BufferEnd);
appendChar(&Buffer, BufferEnd + 1, '\0');
return Res;
}
int formatString(char *Buffer, uptr BufferLength, const char *Format, ...) {
va_list Args;
va_start(Args, Format);
int Res = formatString(Buffer, BufferLength, Format, Args);
va_end(Args);
return Res;
}
void ScopedString::vappend(const char *Format, va_list Args) {
va_list ArgsCopy;
va_copy(ArgsCopy, Args);
// formatString doesn't currently support a null buffer or zero buffer length,
// so in order to get the resulting formatted string length, we use a one-char
// buffer.
char C[1];
const uptr AdditionalLength =
static_cast<uptr>(formatString(C, sizeof(C), Format, Args)) + 1;
const uptr Length = length();
String.resize(Length + AdditionalLength);
const uptr FormattedLength = static_cast<uptr>(formatString(
String.data() + Length, String.size() - Length, Format, ArgsCopy));
RAW_CHECK(data()[length()] == '\0');
RAW_CHECK(FormattedLength + 1 == AdditionalLength);
va_end(ArgsCopy);
}
void ScopedString::append(const char *Format, ...) {
va_list Args;
va_start(Args, Format);
vappend(Format, Args);
va_end(Args);
}
void Printf(const char *Format, ...) {
va_list Args;
va_start(Args, Format);
ScopedString Msg;
Msg.vappend(Format, Args);
outputRaw(Msg.data());
va_end(Args);
}
} // namespace scudo
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