lxccontainer: rework copy_file()

Signed-off-by: Christian Brauner <christian@brauner.io>
resurrect file_exists(new) check
Signed-off-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@canonical.com>

diff --git a/src/lxc/lxccontainer.c b/src/lxc/lxccontainer.c
index 8a2efc2032d05af6e954d51ddc84c0555a05ab09..017e86a097e1265d955c857c3e046e7f19f26c73 100644 (file)
--- a/src/lxc/lxccontainer.c
+++ b/src/lxc/lxccontainer.c
@@ -3282,7 +3282,7 @@ const char *lxc_get_version(void)
 
 static int copy_file(const char *old, const char *new)
 {
-       int in, out;
+       __do_close int fd_from = -EBADF, fd_to = -EBADF;
        ssize_t len, ret;
        char buf[8096];
        struct stat sbuf;
@@ -3292,58 +3292,38 @@ static int copy_file(const char *old, const char *new)
                return -1;
        }
 
-       ret = stat(old, &sbuf);
-       if (ret < 0) {
-               INFO("Error stat'ing %s", old);
-               return -1;
-       }
+       fd_from = open(old, PROTECT_OPEN);
+       if (fd_from < 0)
+               return syserror("Error opening original file %s", old);
 
-       in = open(old, O_RDONLY);
-       if (in < 0) {
-               SYSERROR("Error opening original file %s", old);
-               return -1;
-       }
+       ret = fstat(fd_from, &sbuf);
+       if (ret < 0)
+               return sysinfo("Error stat'ing %s", old);
 
-       out = open(new, O_CREAT | O_EXCL | O_WRONLY, 0644);
-       if (out < 0) {
-               SYSERROR("Error opening new file %s", new);
-               close(in);
-               return -1;
-       }
+       fd_to = open(new, PROTECT_OPEN_W | O_CREAT | O_EXCL, 0644);
+       if (fd_to < 0)
+               return syserror("Error opening new file %s", new);
 
        for (;;) {
-               len = lxc_read_nointr(in, buf, 8096);
-               if (len < 0) {
-                       SYSERROR("Error reading old file %s", old);
-                       goto err;
-               }
+               len = lxc_read_nointr(fd_from, buf, 8096);
+               if (len < 0)
+                       return syserror("Error reading old file %s", old);
 
                if (len == 0)
                        break;
 
-               ret = lxc_write_nointr(out, buf, len);
-               if (ret < len) { /* should we retry? */
-                       SYSERROR("Error: write to new file %s was interrupted", new);
-                       goto err;
-               }
+               ret = lxc_write_nointr(fd_to, buf, len);
+               if (ret < len)
+                       return syserror("Error: write to new file %s was interrupted", new);
        }
 
-       close(in);
-       close(out);
 
        /* We set mode, but not owner/group. */
-       ret = chmod(new, sbuf.st_mode);
-       if (ret) {
-               SYSERROR("Error setting mode on %s", new);
-               return -1;
-       }
+       ret = fchmod(fd_to, sbuf.st_mode);
+       if (ret < 0)
+               return syserror("Error setting mode on %s", new);
 
        return 0;
-
-err:
-       close(in);
-       close(out);
-       return -1;
 }
 
 static int copyhooks(struct lxc_container *oldc, struct lxc_container *c)