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LibC+Kernel: Remove global variable use from snprintf and fprintf
The global variable use in these functions is super thread-unsafe and means that any concurrent calls to sprintf or fprintf in a process could race with each other and end up writing unexpected results. We can just replace the function + global variable with a lambda that captures the relevant argument when calling printf_internal instead.
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parent
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commit
353e72ac9b
Notes:
sideshowbarker
2024-07-17 19:07:08 +09:00
Author: https://github.com/ADKaster Commit: https://github.com/SerenityOS/serenity/commit/353e72ac9b Pull-request: https://github.com/SerenityOS/serenity/pull/12374
@ -123,26 +123,24 @@ int sprintf(char* buffer, const char* fmt, ...)
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return ret;
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}
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static size_t __vsnprintf_space_remaining;
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ALWAYS_INLINE void sized_buffer_putch(char*& bufptr, char ch)
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{
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if (__vsnprintf_space_remaining) {
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*bufptr++ = ch;
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--__vsnprintf_space_remaining;
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}
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}
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int snprintf(char* buffer, size_t size, const char* fmt, ...)
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{
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va_list ap;
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va_start(ap, fmt);
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size_t space_remaining = 0;
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if (size) {
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__vsnprintf_space_remaining = size - 1;
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space_remaining = size - 1;
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} else {
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__vsnprintf_space_remaining = 0;
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space_remaining = 0;
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}
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auto sized_buffer_putch = [&](char*& bufptr, char ch) {
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if (space_remaining) {
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*bufptr++ = ch;
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--space_remaining;
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}
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};
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int ret = printf_internal(sized_buffer_putch, buffer, fmt, ap);
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if (__vsnprintf_space_remaining) {
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if (space_remaining) {
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buffer[ret] = '\0';
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} else if (size > 0) {
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buffer[size - 1] = '\0';
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@ -870,17 +870,10 @@ ALWAYS_INLINE void stdout_putch(char*&, char ch)
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putchar(ch);
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}
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static FILE* __current_stream = nullptr;
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ALWAYS_INLINE static void stream_putch(char*&, char ch)
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{
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fputc(ch, __current_stream);
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}
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// https://pubs.opengroup.org/onlinepubs/9699919799/functions/vfprintf.html
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int vfprintf(FILE* stream, const char* fmt, va_list ap)
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{
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__current_stream = stream;
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return printf_internal(stream_putch, nullptr, fmt, ap);
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return printf_internal([stream](auto, char ch) { fputc(ch, stream); }, nullptr, fmt, ap);
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}
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// https://pubs.opengroup.org/onlinepubs/9699919799/functions/fprintf.html
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@ -957,25 +950,23 @@ int sprintf(char* buffer, const char* fmt, ...)
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return ret;
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}
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static size_t __vsnprintf_space_remaining;
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ALWAYS_INLINE void sized_buffer_putch(char*& bufptr, char ch)
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{
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if (__vsnprintf_space_remaining) {
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*bufptr++ = ch;
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--__vsnprintf_space_remaining;
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}
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}
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// https://pubs.opengroup.org/onlinepubs/9699919799/functions/vsnprintf.html
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int vsnprintf(char* buffer, size_t size, const char* fmt, va_list ap)
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{
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size_t space_remaining = 0;
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if (size) {
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__vsnprintf_space_remaining = size - 1;
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space_remaining = size - 1;
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} else {
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__vsnprintf_space_remaining = 0;
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space_remaining = 0;
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}
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auto sized_buffer_putch = [&](char*& bufptr, char ch) {
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if (space_remaining) {
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*bufptr++ = ch;
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--space_remaining;
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}
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};
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int ret = printf_internal(sized_buffer_putch, buffer, fmt, ap);
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if (__vsnprintf_space_remaining) {
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if (space_remaining) {
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buffer[ret] = '\0';
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} else if (size > 0) {
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buffer[size - 1] = '\0';
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