copy_file(): remove incomplete file on error (bug 2890715)

The behavior changed, data is first written to a temporary file,
which is unlinked in case of error, then the tempfile is renamed
to the final name.
Size of buffer was increased from 4k to 16k.

diff --git a/src/ui_fileops.c b/src/ui_fileops.c
index 11bf4c0..07e5f0e 100644 (file)
--- a/src/ui_fileops.c
+++ b/src/ui_fileops.c
@@ -520,52 +520,66 @@ gboolean copy_file(const gchar *s, const gchar *t)
 {
        FILE *fi = NULL;
        FILE *fo = NULL;
-       gchar *sl, *tl;
-       gchar buf[4096];
+       gchar *sl = NULL;
+       gchar *tl = NULL;
+       gchar *randname = NULL;
+       gchar buf[16384];
        size_t b;
+       gint ret = FALSE;
+       gint fd = -1;
 
        sl = path_from_utf8(s);
        tl = path_from_utf8(t);
 
        if (hard_linked(sl, tl))
                {
-               g_free(sl);
-               g_free(tl);
-               return TRUE;
+               ret = TRUE;
+               goto end;
                }
 
        fi = fopen(sl, "rb");
-       if (fi)
-               {
-               fo = fopen(tl, "wb");
-               if (!fo)
-                       {
-                       fclose(fi);
-                       fi = NULL;
-                       }
-               }
-
-       g_free(sl);
-       g_free(tl);
-
-       if (!fi || !fo) return FALSE;
+       if (!fi) goto end;
+       
+       /* First we write to a temporary file, then we rename it on success,
+          and attributes from original file are copied */
+       randname = g_strconcat(tl, ".tmp_XXXXXX", NULL);
+       if (!randname) goto end;
+       
+       fd = g_mkstemp(randname);
+       if (fd == -1) goto end;
+       
+       fo = fdopen(fd, "wb");
+       if (!fo) {
+               close(fd);
+               goto end;
+       }
 
        while ((b = fread(buf, sizeof(gchar), sizeof(buf), fi)) && b != 0)
                {
                if (fwrite(buf, sizeof(gchar), b, fo) != b)
                        {
-                       fclose(fi);
-                       fclose(fo);
-                       return FALSE;
+                       unlink(randname);
+                       goto end;
                        }
                }
 
-       fclose(fi);
-       fclose(fo);
+       fclose(fi); fi = NULL;
+       fclose(fo); fo = NULL;
 
-       copy_file_attributes(s, t, TRUE, TRUE);
+       if (rename(randname, tl) < 0) {
+               unlink(randname);
+               goto end;       
+       }
 
-       return TRUE;
+       ret = copy_file_attributes(s, t, TRUE, TRUE);
+
+end:
+       if (fi) fclose(fi);
+       if (fo) fclose(fo);
+       if (sl) g_free(sl);
+       if (tl) g_free(tl);
+       if (randname) g_free(randname);
+       return ret;
 }
 
 gboolean move_file(const gchar *s, const gchar *t)