From: Arvin Schnell <aschnell@suse.de>
Date: Fri, 26 Aug 2011 10:05:31 +0000 (+0200)
Subject: - use clone ioctl with plain copy as fallback
X-Git-Tag: v0.1.3~302
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=e0636b37fd128b533499ee5b467d04615e6bc27c;p=thirdparty%2Fsnapper.git

- use clone ioctl with plain copy as fallback
---

diff --git a/snapper/AppUtil.cc b/snapper/AppUtil.cc
index caaaaf5b..cad4fc4e 100644
--- a/snapper/AppUtil.cc
+++ b/snapper/AppUtil.cc
@@ -290,25 +290,66 @@ void initDefaultLogger()
     }
 
 
-    int
-    clonefile(const string& dest, const string& src, mode_t mode)
+    bool
+    clonefile(int src_fd, int dest_fd)
     {
-	int src_fd = open(src.c_str(), O_RDONLY | O_LARGEFILE);
-
-	int dest_fd = open(dest.c_str(), O_WRONLY | O_LARGEFILE | O_CREAT | O_TRUNC, mode);
-
 #undef BTRFS_IOCTL_MAGIC
 #define BTRFS_IOCTL_MAGIC 0x94
 #undef BTRFS_IOC_CLONE
 #define BTRFS_IOC_CLONE _IOW (BTRFS_IOCTL_MAGIC, 9, int)
 
-	int ret = ioctl(dest_fd, BTRFS_IOC_CLONE, src_fd);
+	int r1 = ioctl(dest_fd, BTRFS_IOC_CLONE, src_fd);
+	if (r1 != 0)
+	{
+	    y2err("ioctl failed errno:" << errno << " (" << strerror(errno) << ")");
+	}
 
-	close(dest_fd);
+	return r1 == 0;
+    }
 
-	close(src_fd);
 
-	return ret;
+    bool
+    copyfile(int src_fd, int dest_fd)
+    {
+	struct stat src_stat;
+	int r1 = fstat(src_fd, &src_stat);
+	if (r1 != 0)
+	{
+	    y2err("fstat failed errno:" << errno << " (" << strerror(errno) << ")");
+	    return false;
+	}
+
+	posix_fadvise(src_fd, 0, src_stat.st_size, POSIX_FADV_SEQUENTIAL);
+
+	static_assert(sizeof(off_t) >= 8, "off_t is too small");
+
+	const off_t block_size = 4096;
+
+	char block[block_size];
+
+	off_t length = src_stat.st_size;
+	while (length > 0)
+	{
+	    off_t t = min(block_size, length);
+
+	    int r2 = read(src_fd, block, t);
+	    if (r2 != t)
+	    {
+		y2err("read failed errno:" << errno << " (" << strerror(errno) << ")");
+		return false;
+	    }
+
+	    int r3 = write(dest_fd, block, t);
+	    if (r3 != t)
+	    {
+		y2err("write failed errno:" << errno << " (" << strerror(errno) << ")");
+		return false;
+	    }
+
+	    length -= t;
+	}
+
+	return true;
     }
 
 
diff --git a/snapper/AppUtil.h b/snapper/AppUtil.h
index fb2d8497..5e615a39 100644
--- a/snapper/AppUtil.h
+++ b/snapper/AppUtil.h
@@ -48,7 +48,8 @@ bool checkDir(const string& Path_Cv);
 
     FILE* mkstemp(string& path);
 
-    int clonefile(const string& dest, const string& src, mode_t mode);
+    bool clonefile(int src_fd, int dest_fd);
+    bool copyfile(int src_fd, int dest_fd);
 
     int readlink(const string& path, string& buf);
     int symlink(const string& oldpath, const string& newpath);
diff --git a/snapper/File.cc b/snapper/File.cc
index c009a7d8..b0ec47ee 100644
--- a/snapper/File.cc
+++ b/snapper/File.cc
@@ -26,6 +26,7 @@
 #include <unistd.h>
 #include <fnmatch.h>
 #include <errno.h>
+#include <fcntl.h>
 #include <boost/algorithm/string.hpp>
 
 #include "snapper/File.h"
@@ -517,10 +518,46 @@ namespace snapper
     bool
     File::createFile(mode_t mode, uid_t owner, gid_t group) const
     {
-	// TODO: use clonefile
-	SystemCmd cmd(CPBIN " --preserve=mode,ownership " +
-		      getAbsolutePath(LOC_PRE) + " " + getAbsolutePath(LOC_SYSTEM));
-	return cmd.retcode() == 0;
+	int src_fd = open(getAbsolutePath(LOC_PRE).c_str(), O_RDONLY | O_LARGEFILE);
+	if (src_fd < 0)
+	{
+	    y2err("open failed errno:" << errno << " (" << strerror(errno) << ")");
+	    return false;
+	}
+
+	int dest_fd = open(getAbsolutePath(LOC_SYSTEM).c_str(), O_WRONLY | O_LARGEFILE |
+			   O_CREAT | O_TRUNC, mode);
+	if (dest_fd < 0)
+	{
+	    y2err("open failed errno:" << errno << " (" << strerror(errno) << ")");
+	    return false;
+	}
+
+	int r1 = fchmod(dest_fd, mode);
+	if (r1 != 0)
+	{
+	    y2err("fchmod failed errno:" << errno << " (" << strerror(errno) << ")");
+	    return false;
+	}
+
+	int r2 = fchown(dest_fd, owner, group);
+	if (r2 != 0)
+	{
+	    y2err("fchown failed errno:" << errno << " (" << strerror(errno) << ")");
+	    return false;
+	}
+
+	bool ret = clonefile(src_fd, dest_fd) || copyfile(src_fd, dest_fd);
+	if (!ret)
+	{
+	    y2err("clone and copy failed " << getAbsolutePath(LOC_SYSTEM));
+	}
+
+	close(dest_fd);
+
+	close(src_fd);
+
+	return ret;
     }