util-vserver-0.30.208

[util-vserver.git] / lib_internal / unify-deunify.c

diff --git a/lib_internal/unify-deunify.c b/lib_internal/unify-deunify.c
new file mode 100644 (file)
index 0000000..3d03249
--- /dev/null
+++ b/lib_internal/unify-deunify.c
@@ -0,0 +1,125 @@
+// $Id: unify-deunify.c,v 1.2 2004/02/18 04:48:24 ensc Exp $    --*- c -*--
+
+// Copyright (C) 2004 Enrico Scholz <enrico.scholz@informatik.tu-chemnitz.de>
+//  
+// This program is free software; you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation; version 2 of the License.
+//  
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//  
+// You should have received a copy of the GNU General Public License
+// along with this program; if not, write to the Free Software
+// Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+
+
+#ifdef HAVE_CONFIG_H
+#  include <config.h>
+#endif
+
+#include "unify.h"
+#include <stdlib.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <utime.h>
+#include <fcntl.h>
+#include <errno.h>
+
+#define ENSC_WRAPPERS_IO       1
+#include <wrappers.h>
+
+bool
+Unify_deUnify(char const *dst)
+{
+  size_t               l = strlen(dst);
+  char                 tmpfile[l + sizeof(";XXXXXX")];
+  int                  fd_src, fd_tmp;
+  struct stat          st;
+  struct utimbuf       utm;
+
+  fd_src = open(dst, O_RDONLY);
+  if (fd_src==-1) {
+    perror("open()");
+    return false;
+  }
+
+  if (fstat(fd_src, &st)==-1) {
+    perror("fstat()");
+    close(fd_src);
+    return false;
+  }
+  
+  memcpy(tmpfile,   dst, l);
+  memcpy(tmpfile+l, ";XXXXXX", 8);
+  fd_tmp = mkstemp(tmpfile);
+
+  if (fd_tmp==-1) {
+    perror("mkstemp()");
+    tmpfile[0] = '\0';
+    goto err;
+  }
+
+  if (fchown(fd_tmp, st.st_uid, st.st_gid)==-1 ||
+      fchmod(fd_tmp, st.st_mode)==-1) {
+    perror("fchown()/fchmod()");
+    goto err;
+  }
+
+  // todo: acl?
+
+  for (;;) {
+    char       buf[0x4000];
+    ssize_t    len = read(fd_src, buf, sizeof buf);
+    if (len==-1) {
+      perror("read()");
+      goto err;
+    }
+    if (len==0) break;
+
+    if (!WwriteAll(fd_tmp, buf, len, 0)) goto err;
+  }
+
+  if (close(fd_src)==-1) {
+    perror("close()");
+    goto err;
+  }
+  if (close(fd_tmp)==-1) {
+    perror("close()");
+    goto err;
+  }
+  
+  utm.actime  = st.st_atime;
+  utm.modtime = st.st_mtime;
+
+  // ALERT: race !!!
+  if (utime(tmpfile, &utm)==-1) {
+    perror("utime()");
+    goto err1;
+  }
+
+  if (unlink(dst)==-1) {
+    perror("unlink()");
+    goto err1;
+  }
+  
+  // ALERT: race !!!
+  if (rename(tmpfile, dst)==-1) {
+    perror("FATAL error in rename()");
+    _exit(1);
+  }
+
+  return true;
+  
+  err:
+  close(fd_src);
+  close(fd_tmp);
+  err1:
+  if (tmpfile[0]) unlink(tmpfile);
+
+  return false;
+}