kbuild: Use ls(1) instead of stat(1) to obtain file size

stat(1) is not standardized and different implementations have their own
(conflicting) flags for querying the size of a file.

ls(1) provides the same information (value of st.st_size) in the 5th
column, except when the file is a character or block device. This output
is standardized[0]. The -n option turns on -l, which writes lines
formatted like

  "%s %u %s %s %u %s %s\n", <file mode>, <number of links>,
      <owner name>, <group name>, <size>, <date and time>,
      <pathname>

but instead of writing the <owner name> and <group name>, it writes the
numeric owner and group IDs (this avoids /etc/passwd and /etc/group
lookups as well as potential field splitting issues).

The <size> field is specified as "the value that would be returned for
the file in the st_size field of struct stat".

To avoid duplicating logic in several locations in the tree, create
scripts/file-size.sh and update callers to use that instead of stat(1).

[0] http://pubs.opengroup.org/onlinepubs/9699919799/utilities/ls.html#tag_20_73_10

Signed-off-by: Michael Forney <forney@google.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh
index 08ca08e9105c..9045823c7be7 100755
--- a/scripts/link-vmlinux.sh
+++ b/scripts/link-vmlinux.sh
@@ -269,8 +269,8 @@ if [ -n "${CONFIG_KALLSYMS}" ]; then
 	kallsyms .tmp_vmlinux2 .tmp_kallsyms2.o
 
 	# step 3
-	size1=$(stat -c "%s" .tmp_kallsyms1.o)
-	size2=$(stat -c "%s" .tmp_kallsyms2.o)
+	size1=$(${CONFIG_SHELL} "${srctree}/scripts/file-size.sh" .tmp_kallsyms1.o)
+	size2=$(${CONFIG_SHELL} "${srctree}/scripts/file-size.sh" .tmp_kallsyms2.o)
 
 	if [ $size1 -ne $size2 ] || [ -n "${KALLSYMS_EXTRA_PASS}" ]; then
 		kallsymso=.tmp_kallsyms3.o