[PATCH 1/2] Windows libibery: Don't quote args unnecessarily

[Ray Donnelly]

We only quote arguments that contain spaces, \n \t \v
or " characters to prevent wasting 2 characters per
argument of the CreateProcess() 32,768 limit.

libiberty/
	* pex-win32.c (argv_to_cmdline): Don't quote
	args unnecessarily
---
 libiberty/ChangeLog   |  5 +++++
 libiberty/pex-win32.c | 48 +++++++++++++++++++++++++++++++++++++++---------
 2 files changed, 44 insertions(+), 9 deletions(-)

diff --git a/libiberty/ChangeLog b/libiberty/ChangeLog
index d9a208b..f6a4f8f 100644
--- a/libiberty/ChangeLog
+++ b/libiberty/ChangeLog
@@ -1,3 +1,8 @@
+2014-04-14 Ray Donnelly <mingw.android@gmail.com>
+
+	* pex-win32.c (argv_to_cmdline): Don't quote
+	args unnecessarily.
+
 2014-04-17  Jakub Jelinek  <jakub@redhat.com>
 
 	PR sanitizer/56781
diff --git a/libiberty/pex-win32.c b/libiberty/pex-win32.c
index eae72c5..775b53c 100644
--- a/libiberty/pex-win32.c
+++ b/libiberty/pex-win32.c
@@ -340,17 +340,26 @@ argv_to_cmdline (char *const *argv)
   char *p;
   size_t cmdline_len;
   int i, j, k;
+  int needs_quotes;
 
   cmdline_len = 0;
   for (i = 0; argv[i]; i++)
     {
-      /* We quote every last argument.  This simplifies the problem;
-	 we need only escape embedded double-quotes and immediately
+      /* We only quote arguments that contain spaces, \n \t \v or " characters
+	 to prevent wasting 2 chars per argument of the CreateProcess 32k char
+	 limit We need only escape embedded double-quotes and immediately
 	 preceeding backslash characters.  A sequence of backslach characters
 	 that is not follwed by a double quote character will not be
 	 escaped.  */
+      needs_quotes = 0;
       for (j = 0; argv[i][j]; j++)
 	{
+	  if (argv[i][j] == ' '  || argv[i][j] == '\n' ||
+	      argv[i][j] == '\t' || argv[i][j] == '"' )
+	    {
+	      needs_quotes = 1;
+	    }
+
 	  if (argv[i][j] == '"')
 	    {
 	      /* Escape preceeding backslashes.  */
@@ -362,16 +371,34 @@ argv_to_cmdline (char *const *argv)
 	}
       /* Trailing backslashes also need to be escaped because they will be
          followed by the terminating quote.  */
-      for (k = j - 1; k >= 0 && argv[i][k] == '\\'; k--)
-	cmdline_len++;
+      if (needs_quotes)
+        {
+          for (k = j - 1; k >= 0 && argv[i][k] == '\\'; k--)
+            cmdline_len++;
+        }
       cmdline_len += j;
-      cmdline_len += 3;  /* for leading and trailing quotes and space */
+      /* for leading and trailing quotes and space */
+      cmdline_len += needs_quotes * 2 + 1;
     }
   cmdline = XNEWVEC (char, cmdline_len);
   p = cmdline;
   for (i = 0; argv[i]; i++)
     {
-      *p++ = '"';
+      needs_quotes = 0;
+      for (j = 0; argv[i][j]; j++)
+        {
+          if (argv[i][j] == ' '  || argv[i][j] == '\n' ||
+              argv[i][j] == '\t' || argv[i][j] == '"' )
+            {
+              needs_quotes = 1;
+              break;
+            }
+        }
+
+      if (needs_quotes)
+        {
+          *p++ = '"';
+        }
       for (j = 0; argv[i][j]; j++)
 	{
 	  if (argv[i][j] == '"')
@@ -382,9 +409,12 @@ argv_to_cmdline (char *const *argv)
 	    }
 	  *p++ = argv[i][j];
 	}
-      for (k = j - 1; k >= 0 && argv[i][k] == '\\'; k--)
-	*p++ = '\\';
-      *p++ = '"';
+      if (needs_quotes)
+        {
+          for (k = j - 1; k >= 0 && argv[i][k] == '\\'; k--)
+            *p++ = '\\';
+          *p++ = '"';
+        }
       *p++ = ' ';
     }
   p[-1] = '\0';
-- 
1.9.2