fixed gz_error/strerror mishap

Author: kunschikov

src/bin/pg_dump/compress_io.c

@@ -422,23 +422,6 @@ WriteDataToArchiveNone(ArchiveHandle *AH, CompressorState *cs,
 }
 
 
-/*----------------------
- * Compressed stream API
- *----------------------
- */
-
-/*
- * cfp represents an open stream, wrapping the underlying FILE or gzFile
- * pointer. This is opaque to the callers.
- */
-struct cfp
-{
-	FILE	   *uncompressedfp;
-#ifdef HAVE_LIBZ
-	gzFile		compressedfp;
-#endif
-};
-
 #ifdef HAVE_LIBZ
 static int	hasSuffix(const char *filename, const char *suffix);
 #endif
@@ -593,7 +576,7 @@ cfread(void *ptr, int size, cfp *fp)
 		ret = gzread(fp->compressedfp, ptr, size);
 		if (ret != size && !gzeof(fp->compressedfp))
 			exit_horribly(modulename,
-					"could not read from input file: %s\n", strerror(errno));
+					"could not read from input file: %s\n", get_gz_error(fp->compressedfp));
 	}
 	else
 #endif
@@ -629,7 +612,7 @@ cfgetc(cfp *fp)
 		{
 			if (!gzeof(fp->compressedfp))
 				exit_horribly(modulename,
-					"could not read from input file: %s\n", strerror(errno));
+					"could not read from input file: %s\n", get_gz_error(fp->compressedfp));
 			else
 				exit_horribly(modulename,
 							"could not read from input file: end of file\n");
@@ -710,4 +693,16 @@ hasSuffix(const char *filename, const char *suffix)
 				  suffixlen) == 0;
 }
 
+const char *
+get_gz_error(gzFile gzf)
+{
+	int errnum;
+	static const char fallback[] = "Zlib error";
+	const int maxlen = 255;
+	const char *errmsg = gzerror(gzf, &errnum);
+	if(!errmsg || !memchr(errmsg, 0, maxlen))
+		errmsg = fallback;
+
+	return errnum == Z_ERRNO ? strerror(errno) : errmsg;
+}
 #endif

src/bin/pg_dump/compress_io.h

@@ -27,6 +27,24 @@ typedef enum
 	COMPR_ALG_LIBZ
 } CompressionAlgorithm;
 
+/*----------------------
+ * Compressed stream API
+ *----------------------
+ */
+
+/*
+ * cfp represents an open stream, wrapping the underlying FILE or gzFile
+ * pointer. This is opaque to the callers.
+ */
+typedef struct 
+{
+	FILE	   *uncompressedfp;
+#ifdef HAVE_LIBZ
+	gzFile		compressedfp;
+#endif
+} cfp;
+
+
 /* Prototype for callback function to WriteDataToArchive() */
 typedef void (*WriteFunc) (ArchiveHandle *AH, const char *buf, size_t len);
 
@@ -52,10 +70,6 @@ extern void ReadDataFromArchive(ArchiveHandle *AH, int compression,
 extern void WriteDataToArchive(ArchiveHandle *AH, CompressorState *cs,
 				   const void *data, size_t dLen);
 extern void EndCompressor(ArchiveHandle *AH, CompressorState *cs);
-
-
-typedef struct cfp cfp;
-
 extern cfp *cfopen(const char *path, const char *mode, int compression);
 extern cfp *cfopen_read(const char *path, const char *mode);
 extern cfp *cfopen_write(const char *path, const char *mode, int compression);
@@ -65,5 +79,6 @@ extern int	cfgetc(cfp *fp);
 extern char *cfgets(cfp *fp, char *buf, int len);
 extern int	cfclose(cfp *fp);
 extern int	cfeof(cfp *fp);
+extern const char * get_gz_error(gzFile gzf);
 
 #endif

src/bin/pg_dump/pg_backup_directory.c

@@ -42,6 +42,15 @@
 #include <dirent.h>
 #include <sys/stat.h>
 
+#ifdef WRITE_ERROR_EXIT
+#undef WRITE_ERROR_EXIT
+#endif
+#define WRITE_ERROR_EXIT \
+	do { \
+		exit_horribly(modulename, "could not write to output file: %s\n", \
+		ctx && ctx->dataFH && ctx->dataFH->compressedfp? get_gz_error(ctx->dataFH->compressedfp) : strerror(errno)); \
+	} while (0)
+
 typedef struct
 {
 	/*

src/bin/pg_dump/pg_backup_tar.c

@@ -35,6 +35,7 @@
 #include "pgtar.h"
 #include "common/file_utils.h"
 #include "fe_utils/string_utils.h"
+#include "compress_io.h"
 
 #include <sys/stat.h>
 #include <ctype.h>
@@ -556,7 +557,7 @@ _tarReadRaw(ArchiveHandle *AH, void *buf, size_t len, TAR_MEMBER *th, FILE *fh)
 				res = GZREAD(&((char *) buf)[used], 1, len, th->zFH);
 				if (res != len && !GZEOF(th->zFH))
 					exit_horribly(modulename,
-					"could not read from input file: %s\n", strerror(errno));
+					"could not read from input file: %s\n", get_gz_error(th->zFH));
 			}
 			else
 			{