1 files changed, 250 insertions, 0 deletions
diff --git a/src/bin/pg_upgrade/file.c b/src/bin/pg_upgrade/file.c
new file mode 100644
index 00000000000..79d9390216e
--- /dev/null
+++ b/src/bin/pg_upgrade/file.c
@@ -0,0 +1,250 @@
+/*
+ *	file.c
+ *
+ *	file system operations
+ *
+ *	Copyright (c) 2010-2015, PostgreSQL Global Development Group
+ *	src/bin/pg_upgrade/file.c
+ */
+
+#include "postgres_fe.h"
+
+#include "pg_upgrade.h"
+
+#include <fcntl.h>
+
+
+
+#ifndef WIN32
+static int	copy_file(const char *fromfile, const char *tofile, bool force);
+#else
+static int	win32_pghardlink(const char *src, const char *dst);
+#endif
+
+
+/*
+ * copyAndUpdateFile()
+ *
+ *	Copies a relation file from src to dst.  If pageConverter is non-NULL, this function
+ *	uses that pageConverter to do a page-by-page conversion.
+ */
+const char *
+copyAndUpdateFile(pageCnvCtx *pageConverter,
+				  const char *src, const char *dst, bool force)
+{
+	if (pageConverter == NULL)
+	{
+		if (pg_copy_file(src, dst, force) == -1)
+			return getErrorText(errno);
+		else
+			return NULL;
+	}
+	else
+	{
+		/*
+		 * We have a pageConverter object - that implies that the
+		 * PageLayoutVersion differs between the two clusters so we have to
+		 * perform a page-by-page conversion.
+		 *
+		 * If the pageConverter can convert the entire file at once, invoke
+		 * that plugin function, otherwise, read each page in the relation
+		 * file and call the convertPage plugin function.
+		 */
+
+#ifdef PAGE_CONVERSION
+		if (pageConverter->convertFile)
+			return pageConverter->convertFile(pageConverter->pluginData,
+											  dst, src);
+		else
+#endif
+		{
+			int			src_fd;
+			int			dstfd;
+			char		buf[BLCKSZ];
+			ssize_t		bytesRead;
+			const char *msg = NULL;
+
+			if ((src_fd = open(src, O_RDONLY, 0)) < 0)
+				return "could not open source file";
+
+			if ((dstfd = open(dst, O_RDWR | O_CREAT | O_EXCL, S_IRUSR | S_IWUSR)) < 0)
+			{
+				close(src_fd);
+				return "could not create destination file";
+			}
+
+			while ((bytesRead = read(src_fd, buf, BLCKSZ)) == BLCKSZ)
+			{
+#ifdef PAGE_CONVERSION
+				if ((msg = pageConverter->convertPage(pageConverter->pluginData, buf, buf)) != NULL)
+					break;
+#endif
+				if (write(dstfd, buf, BLCKSZ) != BLCKSZ)
+				{
+					msg = "could not write new page to destination";
+					break;
+				}
+			}
+
+			close(src_fd);
+			close(dstfd);
+
+			if (msg)
+				return msg;
+			else if (bytesRead != 0)
+				return "found partial page in source file";
+			else
+				return NULL;
+		}
+	}
+}
+
+
+/*
+ * linkAndUpdateFile()
+ *
+ * Creates a hard link between the given relation files. We use
+ * this function to perform a true in-place update. If the on-disk
+ * format of the new cluster is bit-for-bit compatible with the on-disk
+ * format of the old cluster, we can simply link each relation
+ * instead of copying the data from the old cluster to the new cluster.
+ */
+const char *
+linkAndUpdateFile(pageCnvCtx *pageConverter,
+				  const char *src, const char *dst)
+{
+	if (pageConverter != NULL)
+		return "Cannot in-place update this cluster, page-by-page conversion is required";
+
+	if (pg_link_file(src, dst) == -1)
+		return getErrorText(errno);
+	else
+		return NULL;
+}
+
+
+#ifndef WIN32
+static int
+copy_file(const char *srcfile, const char *dstfile, bool force)
+{
+#define COPY_BUF_SIZE (50 * BLCKSZ)
+
+	int			src_fd;
+	int			dest_fd;
+	char	   *buffer;
+	int			ret = 0;
+	int			save_errno = 0;
+
+	if ((srcfile == NULL) || (dstfile == NULL))
+	{
+		errno = EINVAL;
+		return -1;
+	}
+
+	if ((src_fd = open(srcfile, O_RDONLY, 0)) < 0)
+		return -1;
+
+	if ((dest_fd = open(dstfile, O_RDWR | O_CREAT | (force ? 0 : O_EXCL), S_IRUSR | S_IWUSR)) < 0)
+	{
+		save_errno = errno;
+
+		if (src_fd != 0)
+			close(src_fd);
+
+		errno = save_errno;
+		return -1;
+	}
+
+	buffer = (char *) pg_malloc(COPY_BUF_SIZE);
+
+	/* perform data copying i.e read src source, write to destination */
+	while (true)
+	{
+		ssize_t		nbytes = read(src_fd, buffer, COPY_BUF_SIZE);
+
+		if (nbytes < 0)
+		{
+			save_errno = errno;
+			ret = -1;
+			break;
+		}
+
+		if (nbytes == 0)
+			break;
+
+		errno = 0;
+
+		if (write(dest_fd, buffer, nbytes) != nbytes)
+		{
+			/* if write didn't set errno, assume problem is no disk space */
+			if (errno == 0)
+				errno = ENOSPC;
+			save_errno = errno;
+			ret = -1;
+			break;
+		}
+	}
+
+	pg_free(buffer);
+
+	if (src_fd != 0)
+		close(src_fd);
+
+	if (dest_fd != 0)
+		close(dest_fd);
+
+	if (save_errno != 0)
+		errno = save_errno;
+
+	return ret;
+}
+#endif
+
+
+void
+check_hard_link(void)
+{
+	char		existing_file[MAXPGPATH];
+	char		new_link_file[MAXPGPATH];
+
+	snprintf(existing_file, sizeof(existing_file), "%s/PG_VERSION", old_cluster.pgdata);
+	snprintf(new_link_file, sizeof(new_link_file), "%s/PG_VERSION.linktest", new_cluster.pgdata);
+	unlink(new_link_file);		/* might fail */
+
+	if (pg_link_file(existing_file, new_link_file) == -1)
+	{
+		pg_fatal("Could not create hard link between old and new data directories: %s\n"
+				 "In link mode the old and new data directories must be on the same file system volume.\n",
+				 getErrorText(errno));
+	}
+	unlink(new_link_file);
+}
+
+#ifdef WIN32
+static int
+win32_pghardlink(const char *src, const char *dst)
+{
+	/*
+	 * CreateHardLinkA returns zero for failure
+	 * http://msdn.microsoft.com/en-us/library/aa363860(VS.85).aspx
+	 */
+	if (CreateHardLinkA(dst, src, NULL) == 0)
+		return -1;
+	else
+		return 0;
+}
+#endif
+
+
+/* fopen() file with no group/other permissions */
+FILE *
+fopen_priv(const char *path, const char *mode)
+{
+	mode_t		old_umask = umask(S_IRWXG | S_IRWXO);
+	FILE	   *fp;
+
+	fp = fopen(path, mode);
+	umask(old_umask);
+
+	return fp;
+}