[libc] Add printf error handling

libc/src/stdio/asprintf.cpp

@@ -22,8 +22,17 @@ LLVM_LIBC_FUNCTION(int, asprintf,
                                  // and pointer semantics, as well as handling
                                  // destruction automatically.
   va_end(vlist);
-  int ret = printf_core::vasprintf_internal(buffer, format, args);
-  return ret;
+  auto ret_val = printf_core::vasprintf_internal(buffer, format, args);
+  if (ret_val.has_error()) {
+    libc_errno = ret_val.error;
+    return -1;
+  }
+  if (ret_val.value > cpp::numeric_limits<int>::max()) {
+    libc_errno = EOVERFLOW;
+    return -1;
+  }
+
+  return static_cast<int>(ret_val.value);
 }
 
 } // namespace LIBC_NAMESPACE_DECL

libc/src/stdio/baremetal/printf.cpp

@@ -42,13 +42,24 @@ LLVM_LIBC_FUNCTION(int, printf, (const char *__restrict format, ...)) {
       buffer, BUFF_SIZE, &stdout_write_hook, nullptr);
   printf_core::Writer<printf_core::WriteMode::FLUSH_TO_STREAM> writer(wb);
 
-  int retval = printf_core::printf_main(&writer, format, args);
+  auto retval = printf_core::printf_main(&writer, format, args);
+  if (retval.has_error()) {
+    libc_errno = retval.error;
+    return -1;
+  }
 
   int flushval = wb.overflow_write("");
-  if (flushval != printf_core::WRITE_OK)
-    retval = flushval;
+  if (flushval != printf_core::WRITE_OK) {
+    libc_errno = -flushval;
+    return -1;
+  }
 
-  return retval;
+  if (retval.value > cpp::numeric_limits<int>::max()) {
+    libc_errno = EOVERFLOW;
+    return -1;
+  }
+
+  return static_cast<int>(retval.value);
 }
 
 } // namespace LIBC_NAMESPACE_DECL

libc/src/stdio/baremetal/vprintf.cpp

@@ -40,13 +40,24 @@ LLVM_LIBC_FUNCTION(int, vprintf,
       buffer, BUFF_SIZE, &stdout_write_hook, nullptr);
   printf_core::Writer<printf_core::WriteMode::FLUSH_TO_STREAM> writer(wb);
 
-  int retval = printf_core::printf_main(&writer, format, args);
+  auto retval = printf_core::printf_main(&writer, format, args);
+  if (retval.has_error()) {
+    libc_errno = retval.error;
+    return -1;
+  }
 
   int flushval = wb.overflow_write("");
-  if (flushval != printf_core::WRITE_OK)
-    retval = flushval;
+  if (flushval != printf_core::WRITE_OK) {
+    libc_errno = -flushval;
+    return -1;
+  }
 
-  return retval;
+  if (retval.value > cpp::numeric_limits<int>::max()) {
+    libc_errno = EOVERFLOW;
+    return -1;
+  }
+
+  return static_cast<int>(retval.value);
 }
 
 } // namespace LIBC_NAMESPACE_DECL

libc/src/stdio/generic/fprintf.cpp

@@ -27,8 +27,17 @@ LLVM_LIBC_FUNCTION(int, fprintf,
                                  // and pointer semantics, as well as handling
                                  // destruction automatically.
   va_end(vlist);
-  int ret_val = printf_core::vfprintf_internal(stream, format, args);
-  return ret_val;
+  auto ret_val = printf_core::vfprintf_internal(stream, format, args);
+  if (ret_val.has_error()) {
+    libc_errno = ret_val.error;
+    return -1;
+  }
+  if (ret_val.value > cpp::numeric_limits<int>::max()) {
+    libc_errno = EOVERFLOW;
+    return -1;
+  }
+
+  return static_cast<int>(ret_val.value);
 }
 
 } // namespace LIBC_NAMESPACE_DECL

libc/src/stdio/generic/printf.cpp

@@ -31,9 +31,18 @@ LLVM_LIBC_FUNCTION(int, printf, (const char *__restrict format, ...)) {
                                  // and pointer semantics, as well as handling
                                  // destruction automatically.
   va_end(vlist);
-  int ret_val = printf_core::vfprintf_internal(
+  auto ret_val = printf_core::vfprintf_internal(
       reinterpret_cast<::FILE *>(PRINTF_STDOUT), format, args);
-  return ret_val;
+  if (ret_val.has_error()) {
+    libc_errno = ret_val.error;
+    return -1;
+  }
+  if (ret_val.value > cpp::numeric_limits<int>::max()) {
+    libc_errno = EOVERFLOW;
+    return -1;
+  }
+
+  return static_cast<int>(ret_val.value);
 }
 
 } // namespace LIBC_NAMESPACE_DECL

libc/src/stdio/generic/vfprintf.cpp

@@ -24,8 +24,17 @@ LLVM_LIBC_FUNCTION(int, vfprintf,
   internal::ArgList args(vlist); // This holder class allows for easier copying
                                  // and pointer semantics, as well as handling
                                  // destruction automatically.
-  int ret_val = printf_core::vfprintf_internal(stream, format, args);
-  return ret_val;
+  auto ret_val = printf_core::vfprintf_internal(stream, format, args);
+  if (ret_val.has_error()) {
+    libc_errno = ret_val.error;
+    return -1;
+  }
+  if (ret_val.value > cpp::numeric_limits<int>::max()) {
+    libc_errno = EOVERFLOW;
+    return -1;
+  }
+
+  return static_cast<int>(ret_val.value);
 }
 
 } // namespace LIBC_NAMESPACE_DECL

libc/src/stdio/generic/vprintf.cpp

@@ -29,9 +29,18 @@ LLVM_LIBC_FUNCTION(int, vprintf,
   internal::ArgList args(vlist); // This holder class allows for easier copying
                                  // and pointer semantics, as well as handling
                                  // destruction automatically.
-  int ret_val = printf_core::vfprintf_internal(
+  auto ret_val = printf_core::vfprintf_internal(
       reinterpret_cast<::FILE *>(PRINTF_STDOUT), format, args);
-  return ret_val;
+  if (ret_val.has_error()) {
+    libc_errno = ret_val.error;
+    return -1;
+  }
+  if (ret_val.value > cpp::numeric_limits<int>::max()) {
+    libc_errno = EOVERFLOW;
+    return -1;
+  }
+
+  return static_cast<int>(ret_val.value);
 }
 
 } // namespace LIBC_NAMESPACE_DECL

libc/src/stdio/printf_core/core_structs.h

@@ -22,6 +22,18 @@
 namespace LIBC_NAMESPACE_DECL {
 namespace printf_core {
 
+struct PrintfResult {
+  size_t value;
+  int error;
+
+  constexpr PrintfResult(size_t val) : value(val), error(0) {}
+  constexpr PrintfResult(size_t val, int error) : value(val), error(error) {}
+
+  constexpr bool has_error() { return error != 0; }
+
+  constexpr operator size_t() { return value; }
+};
+
 // These length modifiers match the length modifiers in the format string, which
 // is why they are formatted differently from the rest of the file.
 enum class LengthModifier { hh, h, l, ll, j, z, t, L, w, wf, none };
@@ -132,14 +144,6 @@ template <typename T> LIBC_INLINE constexpr TypeDesc type_desc_from_type() {
 
 // This is the value to be returned by conversions when no error has occurred.
 constexpr int WRITE_OK = 0;
-// These are the printf return values for when an error has occurred. They are
-// all negative, and should be distinct.
-constexpr int FILE_WRITE_ERROR = -1;
-constexpr int FILE_STATUS_ERROR = -2;
-constexpr int NULLPTR_WRITE_ERROR = -3;
-constexpr int INT_CONVERSION_ERROR = -4;
-constexpr int FIXED_POINT_CONVERSION_ERROR = -5;
-constexpr int ALLOCATION_ERROR = -6;
 } // namespace printf_core
 } // namespace LIBC_NAMESPACE_DECL
 

libc/src/stdio/printf_core/fixed_converter.h

@@ -9,6 +9,7 @@
 #ifndef LLVM_LIBC_SRC_STDIO_PRINTF_CORE_FIXED_CONVERTER_H
 #define LLVM_LIBC_SRC_STDIO_PRINTF_CORE_FIXED_CONVERTER_H
 
+#include "hdr/errno_macros.h"
 #include "include/llvm-libc-macros/stdfix-macros.h"
 #include "src/__support/CPP/string_view.h"
 #include "src/__support/ctype_utils.h"
@@ -59,7 +60,7 @@ LIBC_INLINE constexpr uint32_t const_ten_exp(uint32_t exponent) {
       READ_FX_BITS(unsigned LENGTH_MODIFIER accum);                            \
     } else {                                                                   \
       LIBC_ASSERT(false && "Invalid conversion name passed to convert_fixed"); \
-      return FIXED_POINT_CONVERSION_ERROR;                                     \
+      return -EINVAL;                                                          \
     }                                                                          \
   } while (false)
 

libc/src/stdio/printf_core/int_converter.h

@@ -9,6 +9,7 @@
 #ifndef LLVM_LIBC_SRC_STDIO_PRINTF_CORE_INT_CONVERTER_H
 #define LLVM_LIBC_SRC_STDIO_PRINTF_CORE_INT_CONVERTER_H
 
+#include "hdr/errno_macros.h"
 #include "src/__support/CPP/span.h"
 #include "src/__support/CPP/string_view.h"
 #include "src/__support/ctype_utils.h"
@@ -91,7 +92,7 @@ LIBC_INLINE int convert_int(Writer<write_mode> *writer,
   cpp::array<char, details::num_buf_size()> buf;
   auto str = details::num_to_strview(num, buf, to_conv.conv_name);
   if (!str)
-    return INT_CONVERSION_ERROR;
+    return -ERANGE;
 
   size_t digits_written = str->size();
 

libc/src/stdio/printf_core/printf_main.h

@@ -22,8 +22,8 @@ namespace LIBC_NAMESPACE_DECL {
 namespace printf_core {
 
 template <WriteMode write_mode>
-int printf_main(Writer<write_mode> *writer, const char *__restrict str,
-                internal::ArgList &args) {
+PrintfResult printf_main(Writer<write_mode> *writer, const char *__restrict str,
+                         internal::ArgList &args) {
   Parser<internal::ArgList> parser(str, args);
   int result = 0;
   for (FormatSection cur_section = parser.get_next_section();
@@ -33,9 +33,8 @@ int printf_main(Writer<write_mode> *writer, const char *__restrict str,
       result = convert(writer, cur_section);
     else
       result = writer->write(cur_section.raw_string);
-
     if (result < 0)
-      return result;
+      return {0, -result};
   }
 
   return writer->get_chars_written();

libc/src/stdio/printf_core/vasprintf_internal.h

@@ -6,6 +6,7 @@
 //
 //===----------------------------------------------------------------------===//
 
+#include "hdr/errno_macros.h"
 #include "hdr/func/free.h"
 #include "hdr/func/malloc.h"
 #include "hdr/func/realloc.h"
@@ -29,7 +30,7 @@ LIBC_INLINE int resize_overflow_hook(cpp::string_view new_str, void *target) {
   if (new_buff == nullptr) {
     if (wb->buff != wb->init_buff)
       free(wb->buff);
-    return printf_core::ALLOCATION_ERROR;
+    return -ENOMEM;
   }
   if (isBuffOnStack)
     inline_memcpy(new_buff, wb->buff, wb->buff_cur);
@@ -42,27 +43,28 @@ LIBC_INLINE int resize_overflow_hook(cpp::string_view new_str, void *target) {
 
 constexpr size_t DEFAULT_BUFFER_SIZE = 200;
 
-LIBC_INLINE int vasprintf_internal(char **ret, const char *__restrict format,
-                                   internal::ArgList args) {
+LIBC_INLINE PrintfResult vasprintf_internal(char **ret,
+                                            const char *__restrict format,
+                                            internal::ArgList args) {
   char init_buff_on_stack[DEFAULT_BUFFER_SIZE];
   printf_core::WriteBuffer<Mode<WriteMode::RESIZE_AND_FILL_BUFF>::value> wb(
       init_buff_on_stack, DEFAULT_BUFFER_SIZE, resize_overflow_hook);
   printf_core::Writer writer(wb);
 
   auto ret_val = printf_core::printf_main(&writer, format, args);
-  if (ret_val < 0) {
+  if (ret_val.has_error()) {
     *ret = nullptr;
-    return -1;
+    return ret_val;
   }
   if (wb.buff == init_buff_on_stack) {
-    *ret = static_cast<char *>(malloc(ret_val + 1));
+    *ret = static_cast<char *>(malloc(ret_val.value + 1));
     if (ret == nullptr)
-      return printf_core::ALLOCATION_ERROR;
-    inline_memcpy(*ret, wb.buff, ret_val);
+      return {0, ENOMEM};
+    inline_memcpy(*ret, wb.buff, ret_val.value);
   } else {
     *ret = wb.buff;
   }
-  (*ret)[ret_val] = '\0';
+  (*ret)[ret_val.value] = '\0';
   return ret_val;
 }
 } // namespace printf_core

libc/src/stdio/printf_core/vfprintf_internal.h

@@ -9,6 +9,7 @@
 #ifndef LLVM_LIBC_SRC_STDIO_PRINTF_CORE_VFPRINTF_INTERNAL_H
 #define LLVM_LIBC_SRC_STDIO_PRINTF_CORE_VFPRINTF_INTERNAL_H
 
+#include "hdr/errno_macros.h"
 #include "src/__support/File/file.h"
 #include "src/__support/arg_list.h"
 #include "src/__support/macros/attributes.h" // For LIBC_INLINE
@@ -63,23 +64,27 @@ LIBC_INLINE int file_write_hook(cpp::string_view new_str, void *fp) {
   size_t written = internal::fwrite_unlocked(new_str.data(), sizeof(char),
                                              new_str.size(), target_file);
   if (written != new_str.size() || internal::ferror_unlocked(target_file))
-    return FILE_WRITE_ERROR;
+    return -EIO;
   return WRITE_OK;
 }
 
-LIBC_INLINE int vfprintf_internal(::FILE *__restrict stream,
-                                  const char *__restrict format,
-                                  internal::ArgList &args) {
+LIBC_INLINE PrintfResult vfprintf_internal(::FILE *__restrict stream,
+                                           const char *__restrict format,
+                                           internal::ArgList &args) {
   constexpr size_t BUFF_SIZE = 1024;
   char buffer[BUFF_SIZE];
   printf_core::WriteBuffer<Mode<WriteMode::FLUSH_TO_STREAM>::value> wb(
       buffer, BUFF_SIZE, &file_write_hook, reinterpret_cast<void *>(stream));
   Writer writer(wb);
   internal::flockfile(stream);
-  int retval = printf_main(&writer, format, args);
+  auto retval = printf_main(&writer, format, args);
+  if (retval.has_error()) {
+    internal::funlockfile(stream);
+    return retval;
+  }
   int flushval = wb.overflow_write("");
   if (flushval != WRITE_OK)
-    retval = flushval;
+    retval.error = -flushval;
   internal::funlockfile(stream);
   return retval;
 }

libc/src/stdio/printf_core/write_int_converter.h

@@ -9,6 +9,7 @@
 #ifndef LLVM_LIBC_SRC_STDIO_PRINTF_CORE_WRITE_INT_CONVERTER_H
 #define LLVM_LIBC_SRC_STDIO_PRINTF_CORE_WRITE_INT_CONVERTER_H
 
+#include "hdr/errno_macros.h"
 #include "src/__support/macros/config.h"
 #include "src/stdio/printf_core/core_structs.h"
 #include "src/stdio/printf_core/writer.h"
@@ -26,14 +27,14 @@ LIBC_INLINE int convert_write_int(Writer<write_mode> *writer,
 #ifndef LIBC_COPT_PRINTF_NO_NULLPTR_CHECKS
   // This is an additional check added by LLVM-libc.
   if (to_conv.conv_val_ptr == nullptr)
-    return NULLPTR_WRITE_ERROR;
+    return -EINVAL;
 #endif // LIBC_COPT_PRINTF_NO_NULLPTR_CHECKS
 
-  int written = writer->get_chars_written();
+  size_t written = writer->get_chars_written();
 
   switch (to_conv.length_modifier) {
   case LengthModifier::none:
-    *reinterpret_cast<int *>(to_conv.conv_val_ptr) = written;
+    *reinterpret_cast<int *>(to_conv.conv_val_ptr) = static_cast<int>(written);
     break;
   case LengthModifier::l:
     *reinterpret_cast<long *>(to_conv.conv_val_ptr) = written;