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reactos/base/shell/cmd/for.c
Hermès Bélusca-Maïto 0695ecbfd6
[CMD] FOR: Additional Windows' CMD compatibility "fixes" for FOR /F token parsing command. 
This compatibility behaviour implements the buggy behaviour of FOR /F
token parsing that can be observed in Windows' CMD, and that is tested
by the cmd_winetests.
It can be disabled at compile time via the MSCMD_FOR_QUIRKS define.

It fixes additional cmd_winetests, in concert with commit cb2a9c31.

Explanation of the implemented buggy behaviour
==============================================

In principle, the "tokens=x,y,m-n[*]" option describes a list of token
numbers (must be between 1 and 31) that will be assigned into variables.
Theoretically this option does not cumulate: only the latest 'tokens='
specification should be taken into account.

However things are not that simple in practice. First, not all of the
"tokens=" option state is reset when more than one specification is
provided. Second, when specifying a token range, e.g. "1-5", Windows'
CMD just ignores without error ranges that are not specified in
increasing order. Thus for example, a range "5-1" is ignored without
error. Then, token numbers strictly greater than 31 are just ignored,
and if they appear in a range, the whole range is ignored.

Another bug is the following one: suppose that the 'tokens'
specification reads:
  "tokens=1-5,1-30" , or: "tokens=1-5,3" ,
i.e. more than one range, that overlap partially. Then the actual total
number of variables will not be of the larger range size, but will be
the sum, instead.
Thus, in the first example, a total of 5 + 30 == 35 variables (> 31) is
allocated, while in the second example, a total of 5 + 1 == 6 variables
is allocated, even if they won't all store data !!
In the first example, only the first 30 FOR variables will be used, and
the 5 others will contain an empty string. In the second example, only
the first 5 FOR variables will be used, and the other one will be empty.

We also see that due to that, the "Variables" buffer of fixed size
cannot always be used (since it can contain at most 32 variables).

Last but not least, when more than one "tokens=" specification is
provided, for example:
  "tokens=1-31 tokens=1-20"
a total number of 31 FOR variables (because 31 is the max of 31 and 20)
is allocated, **but** only 20 are actually used, and the 11 others
return an empty string.

And in the specification: "tokens=1-31,* tokens=1-20", a total of
31 + 1 + 20 = 52 variables is initialized, but only the first 20 will
be used, and no "remaining-line" token (the '*' one) is used.
2020-09-21 03:31:01 +02:00

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/*
* FOR.C - for internal batch command.
*
*
* History:
*
* 16-Jul-1998 (Hans B Pufal)
* Started.
*
* 16-Jul-1998 (John P Price)
* Separated commands into individual files.
*
* 19-Jul-1998 (Hans B Pufal)
* Implementation of FOR.
*
* 27-Jul-1998 (John P Price <linux-guru@gcfl.net>)
* Added config.h include.
*
* 20-Jan-1999 (Eric Kohl)
* Unicode and redirection safe!
*
* 01-Sep-1999 (Eric Kohl)
* Added help text.
*
* 23-Feb-2001 (Carl Nettelblad <cnettel@hem.passagen.se>)
* Implemented preservation of echo flag. Some other for related
* code in other files fixed, too.
*
* 28-Apr-2005 (Magnus Olsen <magnus@greatlord.com>)
* Remove all hardcoded strings in En.rc
*/
#include "precomp.h"
/* Enable this define for "buggy" Windows' CMD FOR-command compatibility.
* Currently, this enables the buggy behaviour of FOR /F token parsing. */
#define MSCMD_FOR_QUIRKS
/* FOR is a special command, so this function is only used for showing help now */
INT cmd_for(LPTSTR param)
{
TRACE("cmd_for(\'%s\')\n", debugstr_aw(param));
if (!_tcsncmp(param, _T("/?"), 2))
{
ConOutResPaging(TRUE, STRING_FOR_HELP1);
return 0;
}
ParseErrorEx(param);
return 1;
}
/* The stack of current FOR contexts.
* NULL when no FOR command is active */
PFOR_CONTEXT fc = NULL;
/* Get the next element of the FOR's list */
static BOOL GetNextElement(TCHAR **pStart, TCHAR **pEnd)
{
TCHAR *p = *pEnd;
BOOL InQuotes = FALSE;
while (_istspace(*p))
p++;
if (!*p)
return FALSE;
*pStart = p;
while (*p && (InQuotes || !_istspace(*p)))
InQuotes ^= (*p++ == _T('"'));
*pEnd = p;
return TRUE;
}
/* Execute a single instance of a FOR command */
/* Just run the command (variable expansion is done in DoDelayedExpansion) */
#define RunInstance(Cmd) \
ExecuteCommandWithEcho((Cmd)->Subcommands)
/* Check if this FOR should be terminated early */
#define Exiting(Cmd) \
/* Someone might have removed our context */ \
(bCtrlBreak || (fc != (Cmd)->For.Context))
/* Take also GOTO jumps into account */
#define ExitingOrGoto(Cmd) \
(Exiting(Cmd) || (bc && bc->current == NULL))
/* Read the contents of a text file into memory,
* dynamically allocating enough space to hold it all */
static LPTSTR ReadFileContents(FILE *InputFile, TCHAR *Buffer)
{
SIZE_T Len = 0;
SIZE_T AllocLen = 1000;
LPTSTR Contents = cmd_alloc(AllocLen * sizeof(TCHAR));
if (!Contents)
{
WARN("Cannot allocate memory for Contents!\n");
return NULL;
}
while (_fgetts(Buffer, CMDLINE_LENGTH, InputFile))
{
ULONG_PTR CharsRead = _tcslen(Buffer);
while (Len + CharsRead >= AllocLen)
{
LPTSTR OldContents = Contents;
Contents = cmd_realloc(Contents, (AllocLen *= 2) * sizeof(TCHAR));
if (!Contents)
{
WARN("Cannot reallocate memory for Contents!\n");
cmd_free(OldContents);
return NULL;
}
}
_tcscpy(&Contents[Len], Buffer);
Len += CharsRead;
}
Contents[Len] = _T('\0');
return Contents;
}
/* FOR /F: Parse the contents of each file */
static INT ForF(PARSED_COMMAND *Cmd, LPTSTR List, TCHAR *Buffer)
{
LPTSTR Delims = _T(" \t");
PTCHAR DelimsEndPtr = NULL;
TCHAR DelimsEndChr = _T('\0');
TCHAR Eol = _T(';');
INT SkipLines = 0;
DWORD TokensMask = (1 << 1);
#ifdef MSCMD_FOR_QUIRKS
DWORD NumTokens = 1;
DWORD RemainderVar = 0;
#else
DWORD NumTokens = 0;
#endif
TCHAR StringQuote = _T('"');
TCHAR CommandQuote = _T('\'');
LPTSTR Variables[32];
PTCHAR Start, End;
INT Ret = 0;
if (Cmd->For.Params)
{
TCHAR Quote = 0;
PTCHAR Param = Cmd->For.Params;
if (*Param == _T('"') || *Param == _T('\''))
Quote = *Param++;
while (*Param && *Param != Quote)
{
if (*Param <= _T(' '))
{
Param++;
}
else if (_tcsnicmp(Param, _T("delims="), 7) == 0)
{
Param += 7;
/*
* delims=xxx: Specifies the list of characters that separate tokens.
* This option does not cumulate: only the latest 'delims=' specification
* is taken into account.
*/
Delims = Param;
DelimsEndPtr = NULL;
while (*Param && *Param != Quote)
{
if (*Param == _T(' '))
{
PTCHAR FirstSpace = Param;
Param += _tcsspn(Param, _T(" "));
/* Exclude trailing spaces if this is not the last parameter */
if (*Param && *Param != Quote)
{
/* Save where the delimiters specification string ends */
DelimsEndPtr = FirstSpace;
}
break;
}
Param++;
}
if (*Param == Quote)
{
/* Save where the delimiters specification string ends */
DelimsEndPtr = Param++;
}
}
else if (_tcsnicmp(Param, _T("eol="), 4) == 0)
{
Param += 4;
/* eol=c: Lines starting with this character (may be
* preceded by delimiters) are skipped. */
Eol = *Param;
if (Eol != _T('\0'))
Param++;
}
else if (_tcsnicmp(Param, _T("skip="), 5) == 0)
{
/* skip=n: Number of lines to skip at the beginning of each file */
SkipLines = _tcstol(Param + 5, &Param, 0);
if (SkipLines <= 0)
goto error;
}
else if (_tcsnicmp(Param, _T("tokens="), 7) == 0)
{
#ifdef MSCMD_FOR_QUIRKS
DWORD NumToksInSpec = 0; // Number of tokens in this specification.
#endif
Param += 7;
/*
* tokens=x,y,m-n: List of token numbers (must be between 1 and 31)
* that will be assigned into variables. This option does not cumulate:
* only the latest 'tokens=' specification is taken into account.
*
* NOTE: In MSCMD_FOR_QUIRKS mode, for Windows' CMD compatibility,
* not all the tokens-state is reset. This leads to subtle bugs.
*/
TokensMask = 0;
#ifdef MSCMD_FOR_QUIRKS
NumToksInSpec = 0;
// Windows' CMD compatibility: bug: the asterisk-token's position is not reset!
// RemainderVar = 0;
#else
NumTokens = 0;
#endif
while (*Param && *Param != Quote && *Param != _T('*'))
{
INT First = _tcstol(Param, &Param, 0);
INT Last = First;
#ifdef MSCMD_FOR_QUIRKS
if (First < 1)
#else
if ((First < 1) || (First > 31))
#endif
goto error;
if (*Param == _T('-'))
{
/* It's a range of tokens */
Last = _tcstol(Param + 1, &Param, 0);
#ifdef MSCMD_FOR_QUIRKS
/* Ignore the range if the endpoints are not in correct order */
if (Last < 1)
#else
if ((Last < First) || (Last > 31))
#endif
goto error;
}
#ifdef MSCMD_FOR_QUIRKS
/* Ignore the range if the endpoints are not in correct order */
if ((First <= Last) && (Last <= 31))
{
#endif
TokensMask |= (2 << Last) - (1 << First);
#ifdef MSCMD_FOR_QUIRKS
NumToksInSpec += (Last - First + 1);
}
#endif
if (*Param != _T(','))
break;
Param++;
}
/* With an asterisk at the end, an additional variable
* will be created to hold the remainder of the line
* (after the last specified token). */
if (*Param == _T('*'))
{
#ifdef MSCMD_FOR_QUIRKS
RemainderVar = ++NumToksInSpec;
#else
++NumTokens;
#endif
Param++;
}
#ifdef MSCMD_FOR_QUIRKS
NumTokens = max(NumTokens, NumToksInSpec);
#endif
}
else if (_tcsnicmp(Param, _T("useback"), 7) == 0)
{
Param += 7;
/* usebackq: Use alternate quote characters */
StringQuote = _T('\'');
CommandQuote = _T('`');
/* Can be written as either "useback" or "usebackq" */
if (_totlower(*Param) == _T('q'))
Param++;
}
else
{
error:
error_syntax(Param);
return 1;
}
}
}
#ifdef MSCMD_FOR_QUIRKS
/* Windows' CMD compatibility: use the wrongly evaluated number of tokens */
fc->varcount = NumTokens;
/* Allocate a large enough variables array if needed */
if (NumTokens <= ARRAYSIZE(Variables))
{
fc->values = Variables;
}
else
{
fc->values = cmd_alloc(fc->varcount * sizeof(*fc->values));
if (!fc->values)
{
error_out_of_memory();
return 1;
}
}
#else
/* Count how many variables will be set: one for each token,
* plus maybe one for the remainder. */
fc->varcount = NumTokens;
for (NumTokens = 1; NumTokens < 32; ++NumTokens)
fc->varcount += (TokensMask >> NumTokens) & 1;
fc->values = Variables;
#endif
if (*List == StringQuote || *List == CommandQuote)
{
/* Treat the entire "list" as one single element */
Start = List;
End = &List[_tcslen(List)];
goto single_element;
}
/* Loop over each file */
End = List;
while (!ExitingOrGoto(Cmd) && GetNextElement(&Start, &End))
{
FILE* InputFile;
LPTSTR FullInput, In, NextLine;
INT Skip;
single_element:
if (*Start == StringQuote && End[-1] == StringQuote)
{
/* Input given directly as a string */
End[-1] = _T('\0');
FullInput = cmd_dup(Start + 1);
}
else if (*Start == CommandQuote && End[-1] == CommandQuote)
{
/*
* Read input from a command. We let the CRT do the ANSI/UNICODE conversion.
* NOTE: Should we do that, or instead read in binary mode and
* do the conversion by ourselves, using *OUR* current codepage??
*/
End[-1] = _T('\0');
InputFile = _tpopen(Start + 1, _T("r"));
if (!InputFile)
{
error_bad_command(Start + 1);
Ret = 1;
goto Quit;
}
FullInput = ReadFileContents(InputFile, Buffer);
_pclose(InputFile);
}
else
{
/* Read input from a file */
TCHAR Temp = *End;
*End = _T('\0');
StripQuotes(Start);
InputFile = _tfopen(Start, _T("r"));
*End = Temp;
if (!InputFile)
{
error_sfile_not_found(Start);
Ret = 1;
goto Quit;
}
FullInput = ReadFileContents(InputFile, Buffer);
fclose(InputFile);
}
if (!FullInput)
{
error_out_of_memory();
Ret = 1;
goto Quit;
}
/* Patch the delimiters string */
if (DelimsEndPtr)
{
DelimsEndChr = *DelimsEndPtr;
*DelimsEndPtr = _T('\0');
}
/* Loop over the input line by line */
for (In = FullInput, Skip = SkipLines;
!ExitingOrGoto(Cmd) && (In != NULL);
In = NextLine)
{
DWORD RemainingTokens = TokensMask;
LPTSTR* CurVar = fc->values;
ZeroMemory(fc->values, fc->varcount * sizeof(*fc->values));
#ifdef MSCMD_FOR_QUIRKS
NumTokens = fc->varcount;
#endif
NextLine = _tcschr(In, _T('\n'));
if (NextLine)
*NextLine++ = _T('\0');
if (--Skip >= 0)
continue;
/* Ignore lines where the first token starts with the eol character */
In += _tcsspn(In, Delims);
if (*In == Eol)
continue;
/* Loop as long as we have not reached the end of
* the line, and that we have tokens available.
* A maximum of 31 tokens will be enumerated. */
while (*In && ((RemainingTokens >>= 1) != 0))
{
/* Save pointer to this token in a variable if requested */
if (RemainingTokens & 1)
{
#ifdef MSCMD_FOR_QUIRKS
--NumTokens;
#endif
*CurVar++ = In;
}
/* Find end of token */
In += _tcscspn(In, Delims);
/* NULL-terminate it and advance to next token */
if (*In)
{
*In++ = _T('\0');
In += _tcsspn(In, Delims);
}
}
/* Save pointer to remainder of the line if we need to do so */
if (*In)
#ifdef MSCMD_FOR_QUIRKS
if (RemainderVar && (fc->varcount - NumTokens + 1 == RemainderVar))
#endif
{
/* NOTE: This sets fc->values[0] at least, if no tokens
* were initialized so far, since CurVar is initialized
* originally to point to fc->values. */
*CurVar = In;
}
/* Don't run unless we have at least one variable filled */
if (fc->values[0])
Ret = RunInstance(Cmd);
}
/* Restore the delimiters string */
if (DelimsEndPtr)
*DelimsEndPtr = DelimsEndChr;
cmd_free(FullInput);
}
Quit:
#ifdef MSCMD_FOR_QUIRKS
if (fc->values && (fc->values != Variables))
cmd_free(fc->values);
#endif
return Ret;
}
/* FOR /L: Do a numeric loop */
static INT ForLoop(PARSED_COMMAND *Cmd, LPTSTR List, TCHAR *Buffer)
{
enum { START, STEP, END };
INT params[3] = { 0, 0, 0 };
INT i;
INT Ret = 0;
TCHAR *Start, *End = List;
for (i = 0; i < 3 && GetNextElement(&Start, &End); ++i)
params[i] = _tcstol(Start, NULL, 0);
i = params[START];
/*
* Windows' CMD compatibility:
* Contrary to the other FOR-loops, FOR /L does not check
* whether a GOTO has been done, and will continue to loop.
*/
while (!Exiting(Cmd) &&
(params[STEP] >= 0 ? (i <= params[END]) : (i >= params[END])))
{
_itot(i, Buffer, 10);
Ret = RunInstance(Cmd);
i += params[STEP];
}
return Ret;
}
/* Process a FOR in one directory. Stored in Buffer (up to BufPos) is a
* string which is prefixed to each element of the list. In a normal FOR
* it will be empty, but in FOR /R it will be the directory name. */
static INT ForDir(PARSED_COMMAND *Cmd, LPTSTR List, TCHAR *Buffer, TCHAR *BufPos)
{
INT Ret = 0;
TCHAR *Start, *End = List;
while (!ExitingOrGoto(Cmd) && GetNextElement(&Start, &End))
{
if (BufPos + (End - Start) > &Buffer[CMDLINE_LENGTH])
continue;
memcpy(BufPos, Start, (End - Start) * sizeof(TCHAR));
BufPos[End - Start] = _T('\0');
if (_tcschr(BufPos, _T('?')) || _tcschr(BufPos, _T('*')))
{
WIN32_FIND_DATA w32fd;
HANDLE hFind;
TCHAR *FilePart;
StripQuotes(BufPos);
hFind = FindFirstFile(Buffer, &w32fd);
if (hFind == INVALID_HANDLE_VALUE)
continue;
FilePart = _tcsrchr(BufPos, _T('\\'));
FilePart = FilePart ? FilePart + 1 : BufPos;
do
{
if (w32fd.dwFileAttributes & FILE_ATTRIBUTE_HIDDEN)
continue;
if (!(w32fd.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY)
!= !(Cmd->For.Switches & FOR_DIRS))
continue;
if (_tcscmp(w32fd.cFileName, _T(".")) == 0 ||
_tcscmp(w32fd.cFileName, _T("..")) == 0)
continue;
_tcscpy(FilePart, w32fd.cFileName);
Ret = RunInstance(Cmd);
} while (!ExitingOrGoto(Cmd) && FindNextFile(hFind, &w32fd));
FindClose(hFind);
}
else
{
Ret = RunInstance(Cmd);
}
}
return Ret;
}
/* FOR /R: Process a FOR in each directory of a tree, recursively */
static INT ForRecursive(PARSED_COMMAND *Cmd, LPTSTR List, TCHAR *Buffer, TCHAR *BufPos)
{
INT Ret = 0;
HANDLE hFind;
WIN32_FIND_DATA w32fd;
if (BufPos[-1] != _T('\\'))
{
*BufPos++ = _T('\\');
*BufPos = _T('\0');
}
Ret = ForDir(Cmd, List, Buffer, BufPos);
/* NOTE (We don't apply Windows' CMD compatibility here):
* Windows' CMD does not check whether a GOTO has been done,
* and will continue to loop. */
if (ExitingOrGoto(Cmd))
return Ret;
_tcscpy(BufPos, _T("*"));
hFind = FindFirstFile(Buffer, &w32fd);
if (hFind == INVALID_HANDLE_VALUE)
return Ret;
do
{
if (!(w32fd.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY))
continue;
if (_tcscmp(w32fd.cFileName, _T(".")) == 0 ||
_tcscmp(w32fd.cFileName, _T("..")) == 0)
continue;
Ret = ForRecursive(Cmd, List, Buffer, _stpcpy(BufPos, w32fd.cFileName));
/* NOTE (We don't apply Windows' CMD compatibility here):
* Windows' CMD does not check whether a GOTO has been done,
* and will continue to loop. */
} while (!ExitingOrGoto(Cmd) && FindNextFile(hFind, &w32fd));
FindClose(hFind);
return Ret;
}
INT
ExecuteFor(PARSED_COMMAND *Cmd)
{
INT Ret;
LPTSTR List;
PFOR_CONTEXT lpNew;
TCHAR Buffer[CMDLINE_LENGTH]; /* Buffer to hold the variable value */
LPTSTR BufferPtr = Buffer;
List = DoDelayedExpansion(Cmd->For.List);
if (!List)
return 1;
/* Create our FOR context */
lpNew = cmd_alloc(sizeof(FOR_CONTEXT));
if (!lpNew)
{
WARN("Cannot allocate memory for lpNew!\n");
cmd_free(List);
return 1;
}
lpNew->prev = fc;
lpNew->firstvar = Cmd->For.Variable;
lpNew->varcount = 1;
lpNew->values = &BufferPtr;
Cmd->For.Context = lpNew;
fc = lpNew;
/* Run the extended FOR syntax only if extensions are enabled */
if (bEnableExtensions)
{
if (Cmd->For.Switches & FOR_F)
{
Ret = ForF(Cmd, List, Buffer);
}
else if (Cmd->For.Switches & FOR_LOOP)
{
Ret = ForLoop(Cmd, List, Buffer);
}
else if (Cmd->For.Switches & FOR_RECURSIVE)
{
DWORD Len = GetFullPathName(Cmd->For.Params ? Cmd->For.Params : _T("."),
MAX_PATH, Buffer, NULL);
Ret = ForRecursive(Cmd, List, Buffer, &Buffer[Len]);
}
else
{
Ret = ForDir(Cmd, List, Buffer, Buffer);
}
}
else
{
Ret = ForDir(Cmd, List, Buffer, Buffer);
}
/* Remove our context, unless someone already did that */
if (fc == lpNew)
fc = lpNew->prev;
cmd_free(lpNew);
cmd_free(List);
return Ret;
}
/* EOF */
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