[llvm] r334353 - [Support] Expose flattenWindowsCommandLine.
Zachary Turner via llvm-commits
llvm-commits at lists.llvm.org
Sat Jun 9 15:44:44 PDT 2018
Author: zturner
Date: Sat Jun 9 15:44:44 2018
New Revision: 334353
URL: http://llvm.org/viewvc/llvm-project?rev=334353&view=rev
Log:
[Support] Expose flattenWindowsCommandLine.
This function was internal to Program.inc, but I've needed this
on several occasions when I've had to use CreateProcess without
llvm's sys::Execute functions. In doing so, I noticed that the
function was written using unsafe C-string access and was pretty
hard to understand / make sense of, so I've also re-written the
functions to use more modern LLVM constructs.
Modified:
llvm/trunk/include/llvm/Support/Program.h
llvm/trunk/lib/Support/Program.cpp
llvm/trunk/lib/Support/Windows/Program.inc
Modified: llvm/trunk/include/llvm/Support/Program.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Support/Program.h?rev=334353&r1=334352&r2=334353&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Support/Program.h (original)
+++ llvm/trunk/include/llvm/Support/Program.h Sat Jun 9 15:44:44 2018
@@ -133,6 +133,11 @@ namespace sys {
/// Return true if the given arguments fit within system-specific
/// argument length limits.
bool commandLineFitsWithinSystemLimits(StringRef Program,
+ ArrayRef<StringRef> Args);
+
+ /// Return true if the given arguments fit within system-specific
+ /// argument length limits.
+ bool commandLineFitsWithinSystemLimits(StringRef Program,
ArrayRef<const char *> Args);
/// File encoding options when writing contents that a non-UTF8 tool will
@@ -189,6 +194,14 @@ namespace sys {
///< string is non-empty upon return an error occurred while invoking the
///< program.
);
+
+#if defined(_WIN32)
+ /// Given a list of command line arguments, quote and escape them as necessary
+ /// to build a single flat command line appropriate for calling CreateProcess
+ /// on
+ /// Windows.
+ std::string flattenWindowsCommandLine(ArrayRef<StringRef> Args);
+#endif
}
}
Modified: llvm/trunk/lib/Support/Program.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Support/Program.cpp?rev=334353&r1=334352&r2=334353&view=diff
==============================================================================
--- llvm/trunk/lib/Support/Program.cpp (original)
+++ llvm/trunk/lib/Support/Program.cpp Sat Jun 9 15:44:44 2018
@@ -63,6 +63,15 @@ ProcessInfo sys::ExecuteNoWait(StringRef
return PI;
}
+bool sys::commandLineFitsWithinSystemLimits(StringRef Program,
+ ArrayRef<const char *> Args) {
+ SmallVector<StringRef, 8> StringRefArgs;
+ StringRefArgs.reserve(Args.size());
+ for (const char *A : Args)
+ StringRefArgs.emplace_back(A);
+ return commandLineFitsWithinSystemLimits(Program, StringRefArgs);
+}
+
// Include the platform-specific parts of this class.
#ifdef LLVM_ON_UNIX
#include "Unix/Program.inc"
Modified: llvm/trunk/lib/Support/Windows/Program.inc
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Support/Windows/Program.inc?rev=334353&r1=334352&r2=334353&view=diff
==============================================================================
--- llvm/trunk/lib/Support/Windows/Program.inc (original)
+++ llvm/trunk/lib/Support/Windows/Program.inc Sat Jun 9 15:44:44 2018
@@ -23,6 +23,7 @@
#include <fcntl.h>
#include <io.h>
#include <malloc.h>
+#include <numeric>
//===----------------------------------------------------------------------===//
//=== WARNING: Implementation here must contain only Win32 specific code
@@ -146,108 +147,13 @@ static HANDLE RedirectIO(Optional<String
return h;
}
-/// ArgNeedsQuotes - Check whether argument needs to be quoted when calling
-/// CreateProcess.
-static bool ArgNeedsQuotes(const char *Str) {
- return Str[0] == '\0' || strpbrk(Str, "\t \"&\'()*<>\\`^|") != 0;
-}
-
-/// CountPrecedingBackslashes - Returns the number of backslashes preceding Cur
-/// in the C string Start.
-static unsigned int CountPrecedingBackslashes(const char *Start,
- const char *Cur) {
- unsigned int Count = 0;
- --Cur;
- while (Cur >= Start && *Cur == '\\') {
- ++Count;
- --Cur;
- }
- return Count;
-}
-
-/// EscapePrecedingEscapes - Append a backslash to Dst for every backslash
-/// preceding Cur in the Start string. Assumes Dst has enough space.
-static char *EscapePrecedingEscapes(char *Dst, const char *Start,
- const char *Cur) {
- unsigned PrecedingEscapes = CountPrecedingBackslashes(Start, Cur);
- while (PrecedingEscapes > 0) {
- *Dst++ = '\\';
- --PrecedingEscapes;
- }
- return Dst;
-}
-
-/// ArgLenWithQuotes - Check whether argument needs to be quoted when calling
-/// CreateProcess and returns length of quoted arg with escaped quotes
-static unsigned int ArgLenWithQuotes(const char *Str) {
- const char *Start = Str;
- bool Quoted = ArgNeedsQuotes(Str);
- unsigned int len = Quoted ? 2 : 0;
-
- while (*Str != '\0') {
- if (*Str == '\"') {
- // We need to add a backslash, but ensure that it isn't escaped.
- unsigned PrecedingEscapes = CountPrecedingBackslashes(Start, Str);
- len += PrecedingEscapes + 1;
- }
- // Note that we *don't* need to escape runs of backslashes that don't
- // precede a double quote! See MSDN:
- // http://msdn.microsoft.com/en-us/library/17w5ykft%28v=vs.85%29.aspx
-
- ++len;
- ++Str;
- }
-
- if (Quoted) {
- // Make sure the closing quote doesn't get escaped by a trailing backslash.
- unsigned PrecedingEscapes = CountPrecedingBackslashes(Start, Str);
- len += PrecedingEscapes + 1;
- }
-
- return len;
-}
-
}
-static std::unique_ptr<char[]> flattenArgs(const char **Args) {
- // First, determine the length of the command line.
- unsigned len = 0;
- for (unsigned i = 0; Args[i]; i++) {
- len += ArgLenWithQuotes(Args[i]) + 1;
- }
-
- // Now build the command line.
- std::unique_ptr<char[]> command(new char[len+1]);
- char *p = command.get();
-
- for (unsigned i = 0; Args[i]; i++) {
- const char *arg = Args[i];
- const char *start = arg;
-
- bool needsQuoting = ArgNeedsQuotes(arg);
- if (needsQuoting)
- *p++ = '"';
-
- while (*arg != '\0') {
- if (*arg == '\"') {
- // Escape all preceding escapes (if any), and then escape the quote.
- p = EscapePrecedingEscapes(p, start, arg);
- *p++ = '\\';
- }
-
- *p++ = *arg++;
- }
-
- if (needsQuoting) {
- // Make sure our quote doesn't get escaped by a trailing backslash.
- p = EscapePrecedingEscapes(p, start, arg);
- *p++ = '"';
- }
- *p++ = ' ';
- }
-
- *p = 0;
- return command;
+static SmallVector<StringRef, 8> buildArgVector(const char **Args) {
+ SmallVector<StringRef, 8> Result;
+ for (unsigned I = 0; Args[I]; ++I)
+ Result.push_back(StringRef(Args[I]));
+ return Result;
}
static bool Execute(ProcessInfo &PI, StringRef Program, const char **Args,
@@ -270,7 +176,8 @@ static bool Execute(ProcessInfo &PI, Str
// Windows wants a command line, not an array of args, to pass to the new
// process. We have to concatenate them all, while quoting the args that
// have embedded spaces (or are empty).
- std::unique_ptr<char[]> command = flattenArgs(Args);
+ auto ArgVector = buildArgVector(Args);
+ std::string Command = flattenWindowsCommandLine(ArgVector);
// The pointer to the environment block for the new process.
std::vector<wchar_t> EnvBlock;
@@ -353,7 +260,7 @@ static bool Execute(ProcessInfo &PI, Str
}
SmallVector<wchar_t, MAX_PATH> CommandUtf16;
- if (std::error_code ec = windows::UTF8ToUTF16(command.get(), CommandUtf16)) {
+ if (std::error_code ec = windows::UTF8ToUTF16(Command, CommandUtf16)) {
SetLastError(ec.value());
MakeErrMsg(ErrMsg,
std::string("Unable to convert command-line to UTF-16"));
@@ -414,7 +321,60 @@ static bool Execute(ProcessInfo &PI, Str
return true;
}
+static bool argNeedsQuotes(StringRef Arg) {
+ if (Arg.empty())
+ return true;
+ return StringRef::npos != Arg.find_first_of(" \t\n\v\"");
+}
+
+static std::string quoteSingleArg(StringRef Arg) {
+ std::string Result;
+ Result.push_back('"');
+
+ while (!Arg.empty()) {
+ size_t FirstNonBackslash = Arg.find_first_not_of('\\');
+ size_t BackslashCount = FirstNonBackslash;
+ if (FirstNonBackslash == StringRef::npos) {
+ // The entire remainder of the argument is backslashes. Escape all of
+ // them and just early out.
+ BackslashCount = Arg.size();
+ Result.append(BackslashCount * 2, '\\');
+ break;
+ }
+
+ if (Arg[FirstNonBackslash] == '\"') {
+ // This is an embedded quote. Escape all preceding backslashes, then
+ // add one additional backslash to escape the quote.
+ Result.append(BackslashCount * 2 + 1, '\\');
+ Result.push_back('\"');
+ } else {
+ // This is just a normal character. Don't escape any of the preceding
+ // backslashes, just append them as they are and then append the
+ // character.
+ Result.append(BackslashCount, '\\');
+ Result.push_back(Arg[FirstNonBackslash]);
+ }
+
+ // Drop all the backslashes, plus the following character.
+ Arg = Arg.drop_front(FirstNonBackslash + 1);
+ }
+
+ Result.push_back('"');
+ return Result;
+}
+
namespace llvm {
+std::string sys::flattenWindowsCommandLine(ArrayRef<StringRef> Args) {
+ std::string Command;
+ for (StringRef Arg : Args) {
+ Command += argNeedsQuotes(Arg) ? quoteSingleArg(Arg) : Arg;
+
+ Command.push_back(' ');
+ }
+
+ return Command;
+}
+
ProcessInfo sys::Wait(const ProcessInfo &PI, unsigned SecondsToWait,
bool WaitUntilChildTerminates, std::string *ErrMsg) {
assert(PI.Pid && "invalid pid to wait on, process not started?");
@@ -537,19 +497,13 @@ llvm::sys::writeFileWithEncoding(StringR
}
bool llvm::sys::commandLineFitsWithinSystemLimits(StringRef Program,
- ArrayRef<const char *> Args) {
+ ArrayRef<StringRef> Args) {
// The documented max length of the command line passed to CreateProcess.
static const size_t MaxCommandStringLength = 32768;
- // Account for the trailing space for the program path and the
- // trailing NULL of the last argument.
- size_t ArgLength = ArgLenWithQuotes(Program.str().c_str()) + 2;
- for (const char* Arg : Args) {
- // Account for the trailing space for every arg
- ArgLength += ArgLenWithQuotes(Arg) + 1;
- if (ArgLength > MaxCommandStringLength) {
- return false;
- }
- }
- return true;
+ SmallVector<StringRef, 8> FullArgs;
+ FullArgs.push_back(Program);
+ FullArgs.append(Args.begin(), Args.end());
+ std::string Result = flattenWindowsCommandLine(FullArgs);
+ return (Result.size() + 1) <= MaxCommandStringLength;
}
}
More information about the llvm-commits
mailing list