codereview by PostgreSQL team member (Alvaro Herrera): final state of the patch which was commited to git.posgresql.org (https://git.postgresql.org/gitweb/?p=postgresql.git;a=commit;h=4d57e8381677)

Author: kunschikov

src/bin/pg_dump/compress_io.c

@@ -388,7 +388,7 @@ ReadDataFromArchiveZlib(ArchiveHandle *AH, ReadFunc readF)
 	free(out);
 	free(zp);
 }
-#endif   /* HAVE_LIBZ */
+#endif							/* HAVE_LIBZ */
 
 
 /*
@@ -422,6 +422,23 @@ 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
@@ -575,8 +592,14 @@ cfread(void *ptr, int size, cfp *fp)
 	{
 		ret = gzread(fp->compressedfp, ptr, size);
 		if (ret != size && !gzeof(fp->compressedfp))
+		{
+			int			errnum;
+			const char *errmsg = gzerror(fp->compressedfp, &errnum);
+
 			exit_horribly(modulename,
-					"could not read from input file: %s\n", get_gz_error(fp->compressedfp));
+						  "could not read from input file: %s\n",
+						  errnum == Z_ERRNO ? strerror(errno) : errmsg);
+		}
 	}
 	else
 #endif
@@ -612,10 +635,10 @@ cfgetc(cfp *fp)
 		{
 			if (!gzeof(fp->compressedfp))
 				exit_horribly(modulename,
-					"could not read from input file: %s\n", get_gz_error(fp->compressedfp));
+							  "could not read from input file: %s\n", strerror(errno));
 			else
 				exit_horribly(modulename,
-							"could not read from input file: end of file\n");
+							  "could not read from input file: end of file\n");
 		}
 	}
 	else
@@ -678,6 +701,22 @@ cfeof(cfp *fp)
 		return feof(fp->uncompressedfp);
 }
 
+const char *
+get_cfp_error(cfp *fp)
+{
+#ifdef HAVE_LIBZ
+	if (fp->compressedfp)
+	{
+		int			errnum;
+		const char *errmsg = gzerror(fp->compressedfp, &errnum);
+
+		if (errnum != Z_ERRNO)
+			return errmsg;
+	}
+#endif
+	return strerror(errno);
+}
+
 #ifdef HAVE_LIBZ
 static int
 hasSuffix(const char *filename, const char *suffix)
@@ -693,16 +732,4 @@ 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

@@ -27,24 +27,6 @@ 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);
 
@@ -70,6 +52,10 @@ 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);
@@ -79,6 +65,6 @@ 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);
+extern const char *get_cfp_error(cfp *fp);
 
 #endif

src/bin/pg_dump/pg_backup_directory.c

@@ -42,15 +42,6 @@
 #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
 {
 	/*
@@ -361,7 +352,9 @@ _WriteData(ArchiveHandle *AH, const void *data, size_t dLen)
 	lclContext *ctx = (lclContext *) AH->formatData;
 
 	if (dLen > 0 && cfwrite(data, dLen, ctx->dataFH) != dLen)
-		WRITE_ERROR_EXIT;
+		exit_horribly(modulename, "could not write to output file: %s\n",
+					  get_cfp_error(ctx->dataFH));
+
 
 	return;
 }
@@ -499,7 +492,8 @@ _WriteByte(ArchiveHandle *AH, const int i)
 	lclContext *ctx = (lclContext *) AH->formatData;
 
 	if (cfwrite(&c, 1, ctx->dataFH) != 1)
-		WRITE_ERROR_EXIT;
+		exit_horribly(modulename, "could not write to output file: %s\n",
+					  get_cfp_error(ctx->dataFH));
 
 	return 1;
 }
@@ -528,7 +522,8 @@ _WriteBuf(ArchiveHandle *AH, const void *buf, size_t len)
 	lclContext *ctx = (lclContext *) AH->formatData;
 
 	if (cfwrite(buf, len, ctx->dataFH) != len)
-		WRITE_ERROR_EXIT;
+		exit_horribly(modulename, "could not write to output file: %s\n",
+					  get_cfp_error(ctx->dataFH));
 
 	return;
 }

src/bin/pg_dump/pg_backup_tar.c

@@ -35,7 +35,6 @@
 #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>
@@ -556,8 +555,20 @@ _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))
+				{
+#ifdef HAVE_LIBZ
+					int			errnum;
+					const char *errmsg = gzerror(th->zFH, &errnum);
+
 					exit_horribly(modulename,
-					"could not read from input file: %s\n", get_gz_error(th->zFH));
+								  "could not read from input file: %s\n",
+								  errnum == Z_ERRNO ? strerror(errno) : errmsg);
+#else
+					exit_horribly(modulename,
+								  "could not read from input file: %s\n",
+								  strerror(errno));
+#endif
+				}
 			}
 			else
 			{