unposted: add debug code to zclose()

2 files changed, 13 insertions, 1 deletions

diff --git a/ChangeLog b/ChangeLog
index 08d32d493..633a474d2 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,8 @@
 2010-02-22  Peter Stephenson  <pws@csr.com>
 
+	* unposted: Src/utils.c: Add a debug test for trapping bad uses of
+	fdtable when closing fd's in zclose().
+
 	* 27721: Src/compat.c [with unnecessary test removed], Src/exec.c,
 	Src/system.h, Src/utils.c:  update zopenmax() not to examine huge
 	numbers of file descriptors; only call it at initialisation;
@@ -12810,5 +12813,5 @@
 
 *****************************************************
 * This is used by the shell to define $ZSH_PATCHLEVEL
-* $Revision: 1.4912 $
+* $Revision: 1.4913 $
 *****************************************************
diff --git a/Src/utils.c b/Src/utils.c
index 0168c8287..f488d9de6 100644
--- a/Src/utils.c
+++ b/Src/utils.c
@@ -1,3 +1,4 @@
+
 /*
  * utils.c - miscellaneous utilities
  *
@@ -1704,6 +1705,14 @@ mod_export int
 zclose(int fd)
 {
     if (fd >= 0) {
+	/*
+	 * We sometimes zclose() an fd twice where the second
+	 * time is a catch-all in case there was a failure using
+	 * the fd.  This is harmless but we need to trap it
+	 * for the error check here.
+	 */
+	DPUTS2(fd > max_zsh_fd && fdtable[fd] != FDT_UNUSED,
+	       "BUG: fd is %d, max_zsh_fd is %d", fd, max_zsh_fd);
 	fdtable[fd] = FDT_UNUSED;
 	while (max_zsh_fd > 0 && fdtable[max_zsh_fd] == FDT_UNUSED)
 	    max_zsh_fd--;