[PATCH v2 06/15] initramfs: separate reading cpio method from header

From: Taras Kondratiuk
Date: Wed Jan 24 2018 - 22:40:40 EST


From: Mimi Zohar <zohar@xxxxxxxxxxxxxxxxxx>

In preparation for adding xattr support, read the CPIO method
separately from the rest of the header.

Signed-off-by: Mimi Zohar <zohar@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Taras Kondratiuk <takondra@xxxxxxxxx>
---
init/initramfs.c | 15 +++++++++++----
1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/init/initramfs.c b/init/initramfs.c
index 2d5920c094e0..b3d39c8793be 100644
--- a/init/initramfs.c
+++ b/init/initramfs.c
@@ -168,7 +168,7 @@ static void __init parse_header(char *s)
int i;

buf[8] = '\0';
- for (i = 0, s += 6; i < 12; i++, s += 8) {
+ for (i = 0; i < 12; i++, s += 8) {
memcpy(buf, s, 8);
parsed[i] = simple_strtoul(buf, NULL, 16);
}
@@ -189,6 +189,7 @@ static void __init parse_header(char *s)

static int __init do_start(void);
static int __init do_collect(void);
+static int __init do_format(void);
static int __init do_header(void);
static int __init do_skip(void);
static int __init do_name(void);
@@ -233,7 +234,7 @@ static __initdata char *header_buf, *symlink_buf, *name_buf;

static int __init do_start(void)
{
- read_into(header_buf, 110, do_header);
+ read_into(header_buf, 6, do_format);
return 0;
}

@@ -251,7 +252,7 @@ static int __init do_collect(void)
return 0;
}

-static int __init do_header(void)
+static int __init do_format(void)
{
if (memcmp(collected, "070707", 6)==0) {
error("incorrect cpio method used: use -H newc option");
@@ -261,6 +262,12 @@ static int __init do_header(void)
error("no cpio magic");
return 1;
}
+ read_into(header_buf, 104, do_header);
+ return 0;
+}
+
+static int __init do_header(void)
+{
parse_header(collected);
next_header = this_header + N_ALIGN(name_len) + body_len;
next_header = (next_header + 3) & ~3;
@@ -457,7 +464,7 @@ static char * __init unpack_to_rootfs(char *buf, unsigned long len)
const char *compress_name;
static __initdata char msg_buf[64];

- header_buf = kmalloc(110, GFP_KERNEL);
+ header_buf = kmalloc(104, GFP_KERNEL);
symlink_buf = kmalloc(PATH_MAX + 1, GFP_KERNEL);
name_buf = kmalloc(N_ALIGN(PATH_MAX), GFP_KERNEL);

--
2.10.3.dirty