Properly check for readdir/closedir() failures

Clear errno before calling readdir() and handle old MinGW errno bug
while adding full test coverage for readdir/closedir failures.

Backpatch through 8.4.

1 files changed, 30 insertions, 27 deletions

diff --git a/src/bin/pg_resetxlog/pg_resetxlog.c b/src/bin/pg_resetxlog/pg_resetxlog.c
index 28a4f191f34..af2cec7e932 100644
--- a/src/bin/pg_resetxlog/pg_resetxlog.c
+++ b/src/bin/pg_resetxlog/pg_resetxlog.c
@@ -821,8 +821,7 @@ FindEndOfXLOG(void)
 		exit(1);
 	}
 
-	errno = 0;
-	while ((xlde = readdir(xldir)) != NULL)
+	while (errno = 0, (xlde = readdir(xldir)) != NULL)
 	{
 		if (strlen(xlde->d_name) == 24 &&
 			strspn(xlde->d_name, "0123456789ABCDEF") == 24)
@@ -844,25 +843,27 @@ FindEndOfXLOG(void)
 			if (segno > newXlogSegNo)
 				newXlogSegNo = segno;
 		}
-		errno = 0;
 	}
 
 #ifdef WIN32
-	/*
-	 * This fix is in mingw cvs (runtime/mingwex/dirent.c rev 1.4), but not in
-	 * released version
-	 */
+	/* Bug in old Mingw dirent.c;  fixed in mingw-runtime-3.2, 2003-10-10 */
 	if (GetLastError() == ERROR_NO_MORE_FILES)
 		errno = 0;
 #endif
 
 	if (errno)
 	{
-		fprintf(stderr, _("%s: could not read from directory \"%s\": %s\n"),
+		fprintf(stderr, _("%s: could not read directory \"%s\": %s\n"),
+				progname, XLOGDIR, strerror(errno));
+		exit(1);
+	}
+
+	if (closedir(xldir))
+	{
+		fprintf(stderr, _("%s: could not close directory \"%s\": %s\n"),
 				progname, XLOGDIR, strerror(errno));
 		exit(1);
 	}
-	closedir(xldir);
 
 	/*
 	 * Finally, convert to new xlog seg size, and advance by one to ensure we
@@ -892,8 +893,7 @@ KillExistingXLOG(void)
 		exit(1);
 	}
 
-	errno = 0;
-	while ((xlde = readdir(xldir)) != NULL)
+	while (errno = 0, (xlde = readdir(xldir)) != NULL)
 	{
 		if (strlen(xlde->d_name) == 24 &&
 			strspn(xlde->d_name, "0123456789ABCDEF") == 24)
@@ -906,25 +906,27 @@ KillExistingXLOG(void)
 				exit(1);
 			}
 		}
-		errno = 0;
 	}
 
 #ifdef WIN32
-	/*
-	 * This fix is in mingw cvs (runtime/mingwex/dirent.c rev 1.4), but not in
-	 * released version
-	 */
+	/* Bug in old Mingw dirent.c;  fixed in mingw-runtime-3.2, 2003-10-10 */
 	if (GetLastError() == ERROR_NO_MORE_FILES)
 		errno = 0;
 #endif
 
 	if (errno)
 	{
-		fprintf(stderr, _("%s: could not read from directory \"%s\": %s\n"),
+		fprintf(stderr, _("%s: could not read directory \"%s\": %s\n"),
+				progname, XLOGDIR, strerror(errno));
+		exit(1);
+	}
+
+	if (closedir(xldir))
+	{
+		fprintf(stderr, _("%s: could not close directory \"%s\": %s\n"),
 				progname, XLOGDIR, strerror(errno));
 		exit(1);
 	}
-	closedir(xldir);
 }
 
 
@@ -948,8 +950,7 @@ KillExistingArchiveStatus(void)
 		exit(1);
 	}
 
-	errno = 0;
-	while ((xlde = readdir(xldir)) != NULL)
+	while (errno = 0, (xlde = readdir(xldir)) != NULL)
 	{
 		if (strspn(xlde->d_name, "0123456789ABCDEF") == 24 &&
 			(strcmp(xlde->d_name + 24, ".ready") == 0 ||
@@ -963,25 +964,27 @@ KillExistingArchiveStatus(void)
 				exit(1);
 			}
 		}
-		errno = 0;
 	}
 
 #ifdef WIN32
-	/*
-	 * This fix is in mingw cvs (runtime/mingwex/dirent.c rev 1.4), but not in
-	 * released version
-	 */
+	/* Bug in old Mingw dirent.c;  fixed in mingw-runtime-3.2, 2003-10-10 */
 	if (GetLastError() == ERROR_NO_MORE_FILES)
 		errno = 0;
 #endif
 
 	if (errno)
 	{
-		fprintf(stderr, _("%s: could not read from directory \"%s\": %s\n"),
+		fprintf(stderr, _("%s: could not read directory \"%s\": %s\n"),
+				progname, ARCHSTATDIR, strerror(errno));
+		exit(1);
+	}
+
+	if (closedir(xldir))
+	{
+		fprintf(stderr, _("%s: could not close directory \"%s\": %s\n"),
 				progname, ARCHSTATDIR, strerror(errno));
 		exit(1);
 	}
-	closedir(xldir);
 }