1 files changed, 401 insertions, 0 deletions
diff --git a/src/bin/pg_dump/compress_gzip.c b/src/bin/pg_dump/compress_gzip.c
new file mode 100644
index 00000000000..0af65afeb4e
--- /dev/null
+++ b/src/bin/pg_dump/compress_gzip.c
@@ -0,0 +1,401 @@
+/*-------------------------------------------------------------------------
+ *
+ * compress_gzip.c
+ *	 Routines for archivers to read or write a gzip compressed data stream.
+ *
+ * Portions Copyright (c) 1996-2023, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ * IDENTIFICATION
+ *	   src/bin/pg_dump/compress_gzip.c
+ *
+ *-------------------------------------------------------------------------
+ */
+#include "postgres_fe.h"
+#include <unistd.h>
+
+#include "compress_gzip.h"
+#include "pg_backup_utils.h"
+
+#ifdef HAVE_LIBZ
+#include "zlib.h"
+
+/*----------------------
+ * Compressor API
+ *----------------------
+ */
+typedef struct GzipCompressorState
+{
+	z_streamp	zp;
+
+	void	   *outbuf;
+	size_t		outsize;
+} GzipCompressorState;
+
+/* Private routines that support gzip compressed data I/O */
+static void
+DeflateCompressorGzip(ArchiveHandle *AH, CompressorState *cs, bool flush)
+{
+	GzipCompressorState *gzipcs = (GzipCompressorState *) cs->private_data;
+	z_streamp	zp = gzipcs->zp;
+	void	   *out = gzipcs->outbuf;
+	int			res = Z_OK;
+
+	while (gzipcs->zp->avail_in != 0 || flush)
+	{
+		res = deflate(zp, flush ? Z_FINISH : Z_NO_FLUSH);
+		if (res == Z_STREAM_ERROR)
+			pg_fatal("could not compress data: %s", zp->msg);
+		if ((flush && (zp->avail_out < gzipcs->outsize))
+			|| (zp->avail_out == 0)
+			|| (zp->avail_in != 0)
+			)
+		{
+			/*
+			 * Extra paranoia: avoid zero-length chunks, since a zero length
+			 * chunk is the EOF marker in the custom format. This should never
+			 * happen but ...
+			 */
+			if (zp->avail_out < gzipcs->outsize)
+			{
+				/*
+				 * Any write function should do its own error checking but to
+				 * make sure we do a check here as well ...
+				 */
+				size_t		len = gzipcs->outsize - zp->avail_out;
+
+				cs->writeF(AH, (char *) out, len);
+			}
+			zp->next_out = out;
+			zp->avail_out = gzipcs->outsize;
+		}
+
+		if (res == Z_STREAM_END)
+			break;
+	}
+}
+
+static void
+EndCompressorGzip(ArchiveHandle *AH, CompressorState *cs)
+{
+	GzipCompressorState *gzipcs = (GzipCompressorState *) cs->private_data;
+	z_streamp	zp;
+
+	if (gzipcs->zp)
+	{
+		zp = gzipcs->zp;
+		zp->next_in = NULL;
+		zp->avail_in = 0;
+
+		/* Flush any remaining data from zlib buffer */
+		DeflateCompressorGzip(AH, cs, true);
+
+		if (deflateEnd(zp) != Z_OK)
+			pg_fatal("could not close compression stream: %s", zp->msg);
+
+		pg_free(gzipcs->outbuf);
+		pg_free(gzipcs->zp);
+	}
+
+	pg_free(gzipcs);
+	cs->private_data = NULL;
+}
+
+static void
+WriteDataToArchiveGzip(ArchiveHandle *AH, CompressorState *cs,
+					   const void *data, size_t dLen)
+{
+	GzipCompressorState *gzipcs = (GzipCompressorState *) cs->private_data;
+	z_streamp	zp;
+
+	if (!gzipcs->zp)
+	{
+		zp = gzipcs->zp = (z_streamp) pg_malloc(sizeof(z_stream));
+		zp->zalloc = Z_NULL;
+		zp->zfree = Z_NULL;
+		zp->opaque = Z_NULL;
+
+		/*
+		 * outsize is the buffer size we tell zlib it can output to.  We
+		 * actually allocate one extra byte because some routines want to
+		 * append a trailing zero byte to the zlib output.
+		 */
+		gzipcs->outbuf = pg_malloc(ZLIB_OUT_SIZE + 1);
+		gzipcs->outsize = ZLIB_OUT_SIZE;
+
+		/*
+		 * A level of zero simply copies the input one block at the time. This
+		 * is probably not what the user wanted when calling this interface.
+		 */
+		if (cs->compression_spec.level == 0)
+			pg_fatal("requested to compress the archive yet no level was specified");
+
+		if (deflateInit(zp, cs->compression_spec.level) != Z_OK)
+			pg_fatal("could not initialize compression library: %s", zp->msg);
+
+		/* Just be paranoid - maybe End is called after Start, with no Write */
+		zp->next_out = gzipcs->outbuf;
+		zp->avail_out = gzipcs->outsize;
+	}
+
+	gzipcs->zp->next_in = (void *) unconstify(void *, data);
+	gzipcs->zp->avail_in = dLen;
+	DeflateCompressorGzip(AH, cs, false);
+}
+
+static void
+ReadDataFromArchiveGzip(ArchiveHandle *AH, CompressorState *cs)
+{
+	z_streamp	zp;
+	char	   *out;
+	int			res = Z_OK;
+	size_t		cnt;
+	char	   *buf;
+	size_t		buflen;
+
+	zp = (z_streamp) pg_malloc(sizeof(z_stream));
+	zp->zalloc = Z_NULL;
+	zp->zfree = Z_NULL;
+	zp->opaque = Z_NULL;
+
+	buf = pg_malloc(ZLIB_IN_SIZE);
+	buflen = ZLIB_IN_SIZE;
+
+	out = pg_malloc(ZLIB_OUT_SIZE + 1);
+
+	if (inflateInit(zp) != Z_OK)
+		pg_fatal("could not initialize compression library: %s",
+				 zp->msg);
+
+	/* no minimal chunk size for zlib */
+	while ((cnt = cs->readF(AH, &buf, &buflen)))
+	{
+		zp->next_in = (void *) buf;
+		zp->avail_in = cnt;
+
+		while (zp->avail_in > 0)
+		{
+			zp->next_out = (void *) out;
+			zp->avail_out = ZLIB_OUT_SIZE;
+
+			res = inflate(zp, 0);
+			if (res != Z_OK && res != Z_STREAM_END)
+				pg_fatal("could not uncompress data: %s", zp->msg);
+
+			out[ZLIB_OUT_SIZE - zp->avail_out] = '\0';
+			ahwrite(out, 1, ZLIB_OUT_SIZE - zp->avail_out, AH);
+		}
+	}
+
+	zp->next_in = NULL;
+	zp->avail_in = 0;
+	while (res != Z_STREAM_END)
+	{
+		zp->next_out = (void *) out;
+		zp->avail_out = ZLIB_OUT_SIZE;
+		res = inflate(zp, 0);
+		if (res != Z_OK && res != Z_STREAM_END)
+			pg_fatal("could not uncompress data: %s", zp->msg);
+
+		out[ZLIB_OUT_SIZE - zp->avail_out] = '\0';
+		ahwrite(out, 1, ZLIB_OUT_SIZE - zp->avail_out, AH);
+	}
+
+	if (inflateEnd(zp) != Z_OK)
+		pg_fatal("could not close compression library: %s", zp->msg);
+
+	free(buf);
+	free(out);
+	free(zp);
+}
+
+/* Public routines that support gzip compressed data I/O */
+void
+InitCompressorGzip(CompressorState *cs,
+				   const pg_compress_specification compression_spec)
+{
+	GzipCompressorState *gzipcs;
+
+	cs->readData = ReadDataFromArchiveGzip;
+	cs->writeData = WriteDataToArchiveGzip;
+	cs->end = EndCompressorGzip;
+
+	cs->compression_spec = compression_spec;
+
+	gzipcs = (GzipCompressorState *) pg_malloc0(sizeof(GzipCompressorState));
+
+	cs->private_data = gzipcs;
+}
+
+
+/*----------------------
+ * Compress File API
+ *----------------------
+ */
+
+static size_t
+Gzip_read(void *ptr, size_t size, CompressFileHandle *CFH)
+{
+	gzFile		gzfp = (gzFile) CFH->private_data;
+	size_t		ret;
+
+	ret = gzread(gzfp, ptr, size);
+	if (ret != size && !gzeof(gzfp))
+	{
+		int			errnum;
+		const char *errmsg = gzerror(gzfp, &errnum);
+
+		pg_fatal("could not read from input file: %s",
+				 errnum == Z_ERRNO ? strerror(errno) : errmsg);
+	}
+
+	return ret;
+}
+
+static size_t
+Gzip_write(const void *ptr, size_t size, CompressFileHandle *CFH)
+{
+	gzFile		gzfp = (gzFile) CFH->private_data;
+
+	return gzwrite(gzfp, ptr, size);
+}
+
+static int
+Gzip_getc(CompressFileHandle *CFH)
+{
+	gzFile		gzfp = (gzFile) CFH->private_data;
+	int			ret;
+
+	errno = 0;
+	ret = gzgetc(gzfp);
+	if (ret == EOF)
+	{
+		if (!gzeof(gzfp))
+			pg_fatal("could not read from input file: %s", strerror(errno));
+		else
+			pg_fatal("could not read from input file: end of file");
+	}
+
+	return ret;
+}
+
+static char *
+Gzip_gets(char *ptr, int size, CompressFileHandle *CFH)
+{
+	gzFile		gzfp = (gzFile) CFH->private_data;
+
+	return gzgets(gzfp, ptr, size);
+}
+
+static int
+Gzip_close(CompressFileHandle *CFH)
+{
+	gzFile		gzfp = (gzFile) CFH->private_data;
+
+	CFH->private_data = NULL;
+
+	return gzclose(gzfp);
+}
+
+static int
+Gzip_eof(CompressFileHandle *CFH)
+{
+	gzFile		gzfp = (gzFile) CFH->private_data;
+
+	return gzeof(gzfp);
+}
+
+static const char *
+Gzip_get_error(CompressFileHandle *CFH)
+{
+	gzFile		gzfp = (gzFile) CFH->private_data;
+	const char *errmsg;
+	int			errnum;
+
+	errmsg = gzerror(gzfp, &errnum);
+	if (errnum == Z_ERRNO)
+		errmsg = strerror(errno);
+
+	return errmsg;
+}
+
+static int
+Gzip_open(const char *path, int fd, const char *mode, CompressFileHandle *CFH)
+{
+	gzFile		gzfp;
+	char		mode_compression[32];
+
+	if (CFH->compression_spec.level != Z_DEFAULT_COMPRESSION)
+	{
+		/*
+		 * user has specified a compression level, so tell zlib to use it
+		 */
+		snprintf(mode_compression, sizeof(mode_compression), "%s%d",
+				 mode, CFH->compression_spec.level);
+	}
+	else
+		strcpy(mode_compression, mode);
+
+	if (fd >= 0)
+		gzfp = gzdopen(dup(fd), mode_compression);
+	else
+		gzfp = gzopen(path, mode_compression);
+
+	if (gzfp == NULL)
+		return 1;
+
+	CFH->private_data = gzfp;
+
+	return 0;
+}
+
+static int
+Gzip_open_write(const char *path, const char *mode, CompressFileHandle *CFH)
+{
+	char	   *fname;
+	int			ret;
+	int			save_errno;
+
+	fname = psprintf("%s.gz", path);
+	ret = CFH->open_func(fname, -1, mode, CFH);
+
+	save_errno = errno;
+	pg_free(fname);
+	errno = save_errno;
+
+	return ret;
+}
+
+void
+InitCompressFileHandleGzip(CompressFileHandle *CFH,
+						   const pg_compress_specification compression_spec)
+{
+	CFH->open_func = Gzip_open;
+	CFH->open_write_func = Gzip_open_write;
+	CFH->read_func = Gzip_read;
+	CFH->write_func = Gzip_write;
+	CFH->gets_func = Gzip_gets;
+	CFH->getc_func = Gzip_getc;
+	CFH->close_func = Gzip_close;
+	CFH->eof_func = Gzip_eof;
+	CFH->get_error_func = Gzip_get_error;
+
+	CFH->compression_spec = compression_spec;
+
+	CFH->private_data = NULL;
+}
+#else							/* HAVE_LIBZ */
+void
+InitCompressorGzip(CompressorState *cs,
+				   const pg_compress_specification compression_spec)
+{
+	pg_fatal("this build does not support compression with %s", "gzip");
+}
+
+void
+InitCompressFileHandleGzip(CompressFileHandle *CFH,
+						   const pg_compress_specification compression_spec)
+{
+	pg_fatal("this build does not support compression with %s", "gzip");
+}
+#endif							/* HAVE_LIBZ */