From 830fdc4b43332d1c3a36d147449ad40d23f7efde Mon Sep 17 00:00:00 2001
From: Anthony Baxter <anthonybaxter@gmail.com>
Date: Mon, 8 Apr 2002 04:42:09 +0000
Subject: [PATCH] Backport of bug 457466: "popenx() argument mangling hangs
 python" [Win9x only]."

Can't test this myself, but MarkH sez it's ok.
---
 Modules/posixmodule.c |  8 ++++++-
 PC/w9xpopen.c         | 56 +++++++++++++++++++++++++++++++++++++++----
 2 files changed, 59 insertions(+), 5 deletions(-)

diff --git a/Modules/posixmodule.c b/Modules/posixmodule.c
index 1733d870ce3d..f491c47aad9c 100644
--- a/Modules/posixmodule.c
+++ b/Modules/posixmodule.c
@@ -2422,9 +2422,15 @@ _PyPopenCreateProcess(char *cmdstring,
 
 			s2 = (char *)_alloca(x);
 			ZeroMemory(s2, x);
+			/* To maintain correct argument passing semantics,
+			   we pass the command-line as it stands, and allow
+			   quoting to be applied.  w9xpopen.exe will then
+			   use its argv vector, and re-quote the necessary
+			   args for the ultimate child process.
+			*/
 			sprintf(
 				s2,
-				"%s \"%s%s%s\"",
+				"\"%s\" %s%s%s",
 				modulepath,
 				s1,
 				s3,
diff --git a/PC/w9xpopen.c b/PC/w9xpopen.c
index d96d0f5e5876..31448fd81c79 100644
--- a/PC/w9xpopen.c
+++ b/PC/w9xpopen.c
@@ -16,9 +16,10 @@
 
 #define WINDOWS_LEAN_AND_MEAN
 #include <windows.h>
+#include <stdio.h>
 
 const char *usage =
-"This program is used by Python's os.pipe function to\n"
+"This program is used by Python's os.popen function to\n"
 "to work around a limitation in Windows 95/98.  It is\n"
 "not designed to be used as stand-alone program.";
 
@@ -28,11 +29,56 @@ int main(int argc, char *argv[])
     STARTUPINFO si;
     PROCESS_INFORMATION pi;
     DWORD exit_code=0;
+    int cmdlen = 0;
+    int i;
+    char *cmdline, *cmdlinefill;
 
-    if (argc != 2) {
-        MessageBox(NULL, usage, argv[0], MB_OK);
+    if (argc < 2) {
+        if (GetFileType(GetStdHandle(STD_INPUT_HANDLE))==FILE_TYPE_CHAR)
+            /* Attached to a console, and therefore not executed by Python
+               Display a message box for the inquisitive user
+            */
+            MessageBox(NULL, usage, argv[0], MB_OK);
+        else {
+            /* Eeek - executed by Python, but args are screwed!
+               Write an error message to stdout so there is at
+               least some clue for the end user when it appears
+               in their output.
+               A message box would be hidden and blocks the app.
+             */
+            fprintf(stdout, "Internal popen error - no args specified\n%s\n", usage);
+        }
         return 1;
     }
+    /* Build up the command-line from the args.
+       Args with a space are quoted, existing quotes are escaped.
+       To keep things simple calculating the buffer size, we assume
+       every character is a quote - ie, we allocate double what we need
+       in the worst case.  As this is only double the command line passed
+       to us, there is a good chance this is reasonably small, so the total 
+       allocation will almost always be < 512 bytes.
+    */
+    for (i=1;i<argc;i++)
+        cmdlen += strlen(argv[i])*2 + 3; /* one space, maybe 2 quotes */
+    cmdline = cmdlinefill = (char *)malloc(cmdlen+1);
+    if (cmdline == NULL)
+        return -1;
+    for (i=1;i<argc;i++) {
+        const char *arglook;
+        int bQuote = strchr(argv[i], ' ') != NULL;
+        if (bQuote)
+            *cmdlinefill++ = '"';
+        /* escape quotes */
+        for (arglook=argv[i];*arglook;arglook++) {
+            if (*arglook=='"')
+                *cmdlinefill++ = '\\';
+            *cmdlinefill++ = *arglook;
+        }
+        if (bQuote)
+            *cmdlinefill++ = '"';
+        *cmdlinefill++ = ' ';
+    }
+    *cmdlinefill = '\0';
 
     /* Make child process use this app's standard files. */
     ZeroMemory(&si, sizeof si);
@@ -43,13 +89,15 @@ int main(int argc, char *argv[])
     si.hStdError = GetStdHandle(STD_ERROR_HANDLE);
 
     bRet = CreateProcess(
-        NULL, argv[1],
+        NULL, cmdline,
         NULL, NULL,
         TRUE, 0,
         NULL, NULL,
         &si, &pi
         );
 
+    free(cmdline);
+
     if (bRet) {
         if (WaitForSingleObject(pi.hProcess, INFINITE) != WAIT_FAILED) {
 	    GetExitCodeProcess(pi.hProcess, &exit_code);
-- 
2.47.3