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StdLib: Fix IIO_Write() to return the number of bytes consumed, not characters output. 

Depending upon termios settings, writing to a terminal device may result in
many more characters being output than were in the buffer provided to the
IIO_Write() function.

IIO_Write() is supposed to return the number of BYTES written, not characters.
Since the provided buffer contains MBCS characters, there can be up to three
bytes per character.  Due to the expansion that may occur, "BYTES written"
is interpreted to mean the number of BYTES consumed from the MBCS buffer
provided as a parameter to IIO_Write.

These changes ensure that the correct number of characters are consumed from
the internal Output buffer and the correct number of BYTES consumed from the
buffer parameter are counted and returned.

Update copyright.
Fix some indentation and white space issues.
Improve comments for IIO_Write().
Add debugging instrumentation to count unconsumed data in the Input and Output buffers.
Modify IIO_Write() to:
  Accurately count input bytes CONSUMED.
  Consume only as many expanded (cooked) characters from the output buffer
  as were actually sent to the device.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Daryl McDaniel <edk2-lists@mc2research.org>
Reviewed-by: Erik Bjorge <erik.c.bjorge@intel.com>


git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@19589 6f19259b-4bc3-4df7-8a09-765794883524
This commit is contained in:
Daryl McDaniel 2016-01-06 00:44:24 +00:00 committed by darylm503
parent 450ea6d5b6
commit 86f2165dc3
1 changed files with 78 additions and 34 deletions
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108
StdLib/LibC/Uefi/InteractiveIO/IIO.c
View File

@ -3,6 +3,7 @@
The functions assume that isatty() is TRUE at the time they are called.
Copyright (c) 2016, Daryl McDaniel. All rights reserved.<BR>
Copyright (c) 2012, Intel Corporation. All rights reserved.<BR>
This program and the accompanying materials are licensed and made available
under the terms and conditions of the BSD License which accompanies this
@ -26,6 +27,20 @@
#include "IIOutilities.h"
#include "IIOechoCtrl.h"
// Instrumentation used for debugging
#define IIO_C_DEBUG 0 ///< Set to 1 to enable instrumentation, 0 to disable
#if IIO_C_DEBUG
static volatile size_t IIO_C_WRemainder = 0; ///< Characters in Out buffer after IIO_Write
static volatile size_t IIO_C_RRemainder = 0; ///< Characters in In buffer after IIO_Read
#define W_INSTRUMENT IIO_C_WRemainder =
#define R_INSTRUMENT IIO_C_RRemainder =
#else // ! IIO_C_DEBUG -- don't instrument code
#define W_INSTRUMENT (void)
#define R_INSTRUMENT (void)
#endif // IIO_C_DEBUG
/** Read from an Interactive IO device.
NOTE: If _S_IWTTY is set, the internal buffer contains WIDE characters.
@ -82,24 +97,44 @@ IIO_Read(
NumRead = wcstombs((char *)Buffer, (const wchar_t *)gMD->UString2, XlateSz);
// Consume the translated characters
(void)This->InBuf->Flush(This->InBuf, Needed);
(void) This->InBuf->Flush(This->InBuf, Needed);
}
else {
// Data in InBuf is narrow characters. Use verbatim.
NumRead = This->InBuf->Read(This->InBuf, Buffer, (INT32)BufferSize);
}
#if IIO_C_DEBUG
IIO_C_RRemainder = This->InBuf->Count(This->InBuf, AsElements);
#endif // IIO_C_DEBUG
}
return NumRead;
}
/** Process characters from buffer buf and write them to the output device
/** Handle write to a Terminal (Interactive) device.
Processes characters from buffer buf and writes them to the Terminal device
specified by filp.
The parameter buf points to a MBCS string to be output. This is processed
and buffered one character at a time by IIO_WriteOne() which handles TAB
expansion, NEWLINE to CARRIAGE_RETURN + NEWLINE expansion, as well as
basic line editing functions. The number of characters actually written to
the output device will seldom equal the number of characters consumed from
buf.
In this implementation, all of the special characters processed by
IIO_WriteOne() are single-byte characters with values less than 128.
(7-bit ASCII or the single-byte UTF-8 characters)
Every byte that is not one of the recognized special characters is passed,
unchanged, to the Terminal device.
@param[in] filp Pointer to a file descriptor structure.
@param[in] buf Pointer to the MBCS string to be output.
@param[in] N Number of bytes in buf.
@retval >=0 Number of bytes sent to the output device.
@retval >=0 Number of bytes consumed from buf and sent to the
Terminal device.
**/
static
ssize_t
@ -114,16 +149,15 @@ IIO_Write(
cFIFO *OutBuf;
mbstate_t *OutState;
char *MbcsPtr;
ssize_t NumWritten;
ssize_t NumConsumed;
ssize_t NumProc;
size_t CharLen;
UINTN MaxColumn;
UINTN MaxRow;
wchar_t OutChar[2]; // Just in case we run into 4-byte MBCS character
wchar_t OutChar[2]; // Just in case we run into a 4-byte MBCS character
int OutMode;
errno = 0; // indicate no error as default
NumWritten = -1;
NumConsumed = -1;
/* Determine what the current screen size is. Also validates the output device. */
OutMode = IIO_GetOutputSize(filp->MyFD, &MaxColumn, &MaxRow);
@ -148,51 +182,61 @@ IIO_Write(
This->CurrentXY.Column = This->InitialXY.Column;
This->CurrentXY.Row = This->InitialXY.Row;
NumWritten = 0;
NumConsumed = 0;
OutChar[0] = (wchar_t)buf[0];
while((OutChar[0] != 0) && (NumWritten < N)) {
CharLen = mbrtowc(OutChar, (const char *)&buf[NumWritten], MB_CUR_MAX, OutState);
NumProc = IIO_WriteOne(filp, OutBuf, OutChar[0]);
if(NumProc > 0) {
// Successfully processed and buffered one character
NumWritten += CharLen; // Index of start of next character
}
else if(NumProc == -1) {
// Encoding Error
while((OutChar[0] != 0) && (NumConsumed < N)) {
CharLen = mbrtowc(OutChar, (const char *)&buf[NumConsumed], MB_CUR_MAX, OutState);
if (CharLen < 0) { // Encoding Error
OutChar[0] = BLOCKELEMENT_LIGHT_SHADE;
CharLen = 1; // Consume a byte
(void)mbrtowc(NULL, NULL, 1, OutState); // Re-Initialize the conversion state
errno = EILSEQ;
break;
}
NumProc = IIO_WriteOne(filp, OutBuf, OutChar[0]);
if(NumProc >= 0) {
// Successfully processed and buffered one character
NumConsumed += CharLen; // Index of start of next character
}
else {
// Last character was incomplete
if (errno == ENOSPC) {
// Not enough room in OutBuf to hold a potentially expanded character
break;
}
return -1; // Something corrupted and filp->devdata is now NULL
}
}
// At this point, the characters to write are in OutBuf
// First, linearize the buffer
NumWritten = OutBuf->Copy(OutBuf, gMD->UString, UNICODE_STRING_MAX-1);
gMD->UString[NumWritten] = 0; // Ensure that the buffer is terminated
NumProc = OutBuf->Copy(OutBuf, gMD->UString, UNICODE_STRING_MAX-1);
gMD->UString[NumProc] = 0; // Ensure that the buffer is terminated
if(filp->f_iflags & _S_IWTTY) {
// Output device expects wide characters, Output what we have
NumWritten = filp->f_ops->fo_write(filp, NULL, NumWritten, gMD->UString);
NumProc = filp->f_ops->fo_write(filp, NULL, NumProc, gMD->UString);
// Consume the output characters
W_INSTRUMENT OutBuf->Flush(OutBuf, NumProc);
}
else {
// Output device expects narrow characters, convert to MBCS
MbcsPtr = (char *)gMD->UString2;
// Determine the needed space
// Determine the needed space. NumProc is the number of bytes needed.
NumProc = (ssize_t)EstimateWtoM((const wchar_t *)gMD->UString, UNICODE_STRING_MAX * sizeof(wchar_t), &CharLen);
// Now translate this into MBCS in Buffer
NumWritten = wcstombs(MbcsPtr, (const wchar_t *)gMD->UString, NumProc);
MbcsPtr[NumWritten] = 0; // Ensure the buffer is terminated
// Now translate this into MBCS in the buffer pointed to by MbcsPtr.
// The returned value, NumProc, is the resulting number of bytes.
NumProc = wcstombs(MbcsPtr, (const wchar_t *)gMD->UString, NumProc);
MbcsPtr[NumProc] = 0; // Ensure the buffer is terminated
// Send the MBCS buffer to Output
NumWritten = filp->f_ops->fo_write(filp, NULL, NumWritten, MbcsPtr);
NumProc = filp->f_ops->fo_write(filp, NULL, NumProc, MbcsPtr);
// Mark the Mbcs buffer after the last byte actually written
MbcsPtr[NumProc] = 0;
// Count the CHARACTERS actually sent
CharLen = CountMbcsChars(MbcsPtr);
// Consume the number of output characters actually sent
W_INSTRUMENT OutBuf->Flush(OutBuf, CharLen);
}
// Consume the translated characters
(void)OutBuf->Flush(OutBuf, NumWritten);
}
else {
if(This == NULL) {
@ -200,7 +244,7 @@ IIO_Write(
}
// Otherwise, errno is already set.
}
return NumWritten;
return NumConsumed;
}
/** Echo a character to an output device.