From ed0e3b0f38df5d4da54f0d785c29b9f40592fb80 Mon Sep 17 00:00:00 2001
From: Kaz Kylheku <kaz@kylheku.com>
Date: Thu, 30 Jun 2016 23:01:29 -0700
Subject: Cygnal apps use cmd.exe, not /bin/sh.

* winsup/cygwin/include/paths.h (_PATH_CMDEXE): New
preprocessor symbol.

* winsup/cygwin/spawn.cc (av_setup): Use _PATH_CMDEXE
rather than "/bin/sh".

* winsup/cygwin/syscalls.cc (system): Spawn _PATH_CMDEXE
with /c option rather than /bin/sh.
(ETC_SHELLS): Preprocessor symbol removed.
(shell_fp): Global variable removed.
(getusershell): Don't open ETC_SHELLS, just march through
static array of shell names. That array contains only one
entry: _PATH_CMDEXE.
(setusershell, endusershell): Remove references to shell_fp.
(popen): Exec _PATH_CMDEXE rather than "/bin/sh", and the
option is /c.
---
 winsup/cygwin/include/paths.h |  2 +-
 winsup/cygwin/spawn.cc        |  2 +-
 winsup/cygwin/syscalls.cc     | 56 +++++++++----------------------------------
 3 files changed, 13 insertions(+), 47 deletions(-)

diff --git a/winsup/cygwin/include/paths.h b/winsup/cygwin/include/paths.h
index a21591f64..cf25056d8 100644
--- a/winsup/cygwin/include/paths.h
+++ b/winsup/cygwin/include/paths.h
@@ -29,5 +29,5 @@ details. */
 #define _PATH_VARTMP	"/var/tmp/"
 #define _PATH_VI        "/bin/vi"
 #define _PATH_WTMP	"/var/log/wtmp"
-
+#define _PATH_CMDEXE	"C:/Windows/System32/cmd.exe"
 #endif /* _PATHS_H_ */
diff --git a/winsup/cygwin/spawn.cc b/winsup/cygwin/spawn.cc
index 87137cd03..05020952a 100644
--- a/winsup/cygwin/spawn.cc
+++ b/winsup/cygwin/spawn.cc
@@ -1160,7 +1160,7 @@ av::setup (const char *prog_arg, path_conv& real_path, const char *ext,
 	      }
 	    if (ascii_strcasematch (ext, ".com"))
 	      break;
-	    pgm = (char *) "/bin/sh";
+	    pgm = (char *) _PATH_CMDEXE;
 	    arg1 = NULL;
 	  }
 
diff --git a/winsup/cygwin/syscalls.cc b/winsup/cygwin/syscalls.cc
index 61872fe58..db5411fff 100644
--- a/winsup/cygwin/syscalls.cc
+++ b/winsup/cygwin/syscalls.cc
@@ -2620,12 +2620,12 @@ system (const char *cmdstring)
 
   __try
     {
-      command[0] = "sh";
-      command[1] = "-c";
+      command[0] = _PATH_CMDEXE;
+      command[1] = "/c";
       command[2] = cmdstring;
       command[3] = (const char *) NULL;
 
-      if ((res = spawnvp (_P_SYSTEM, "/bin/sh", command)) == -1)
+      if ((res = spawnvp (_P_SYSTEM, _PATH_CMDEXE, command)) == -1)
 	{
 	  // when exec fails, return value should be as if shell
 	  // executed exit (127)
@@ -4147,9 +4147,7 @@ gethostid (void)
   return (int32_t) hostid; /* Avoid sign extension. */
 }
 
-#define ETC_SHELLS "/etc/shells"
 static int shell_index;
-static struct __sFILE64 *shell_fp;
 
 extern "C" char *
 getusershell ()
@@ -4159,58 +4157,26 @@ getusershell ()
      might be shipped with the OS.  Should we do the same for the Cygwin
      distro, adding bash, tcsh, ksh, pdksh and zsh?  */
   static const char *def_shells[] = {
-    "/bin/sh",
-    "/bin/csh",
-    "/usr/bin/sh",
-    "/usr/bin/csh",
+    _PATH_CMDEXE,
     NULL
   };
+
   static char buf[PATH_MAX];
-  int ch, buf_idx;
 
-  if (!shell_fp && !(shell_fp = fopen64 (ETC_SHELLS, "rt")))
-    {
-      if (def_shells[shell_index])
-	return strcpy (buf, def_shells[shell_index++]);
-      return NULL;
-    }
-  /* Skip white space characters. */
-  while ((ch = getc (shell_fp)) != EOF && isspace (ch))
-    ;
-  /* Get each non-whitespace character as part of the shell path as long as
-     it fits in buf. */
-  for (buf_idx = 0;
-       ch != EOF && !isspace (ch) && buf_idx < (PATH_MAX - 1);
-       buf_idx++, ch = getc (shell_fp))
-    buf[buf_idx] = ch;
-  /* Skip any trailing non-whitespace character not fitting in buf.  If the
-     path is longer than PATH_MAX, it's invalid anyway. */
-  while (ch != EOF && !isspace (ch))
-    ch = getc (shell_fp);
-  if (buf_idx)
-    {
-      buf[buf_idx] = '\0';
-      return buf;
-    }
+  if (def_shells[shell_index])
+    return strcpy (buf, def_shells[shell_index++]);
   return NULL;
 }
 
 extern "C" void
 setusershell ()
 {
-  if (shell_fp)
-    fseek (shell_fp, 0L, SEEK_SET);
   shell_index = 0;
 }
 
 extern "C" void
 endusershell ()
 {
-  if (shell_fp)
-    {
-      fclose (shell_fp);
-      shell_fp = NULL;
-    }
   shell_index = 0;
 }
 
@@ -4309,8 +4275,8 @@ popen (const char *command, const char *in_type)
 
       const char *argv[4] =
 	{
-	  "/bin/sh",
-	  "-c",
+	  _PATH_CMDEXE,
+	  "/c",
 	  command,
 	  NULL
 	};
@@ -4330,8 +4296,8 @@ popen (const char *command, const char *in_type)
       fcntl64 (stdchild, F_SETFD, stdchild_state | FD_CLOEXEC);
 
       /* Start a shell process to run the given command without forking. */
-      pid_t pid = ch_spawn.worker ("/bin/sh", argv, cur_environ (), _P_NOWAIT,
-				   __std[0], __std[1]);
+      pid_t pid = ch_spawn.worker (_PATH_CMDEXE, argv, cur_environ (),
+				   _P_NOWAIT, __std[0], __std[1]);
 
       /* Reinstate the close-on-exec state */
       fcntl64 (stdchild, F_SETFD, stdchild_state);
-- 
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