From: Nicolas Pitre <nicolas.pitre@linaro.org>
To: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org
Cc: Alexander Viro <viro@zeniv.linux.org.uk>,
David Howells <dhowells@redhat.com>,
Greg Ungerer <gerg@linux-m68k.org>
Subject: [PATCH v3 12/12] binfmt_flat: allow compressed flat binary format to work on MMU systems
Date: Wed, 20 Jul 2016 00:20:24 -0400 [thread overview]
Message-ID: <1468988424-32671-13-git-send-email-nicolas.pitre@linaro.org> (raw)
In-Reply-To: <1468988424-32671-1-git-send-email-nicolas.pitre@linaro.org>
Let's take the simple and obvious approach by decompressing the binary
into a kernel buffer and then copying it to user space. Those who are
looking for top performance on an MMU system are unlikely to choose this
executable format anyway.
Signed-off-by: Nicolas Pitre <nico@linaro.org>
Reviewed-by: Greg Ungerer <gerg@linux-m68k.org>
---
fs/binfmt_flat.c | 44 ++++++++++++++++++++++++++++++++++++++++++--
1 file changed, 42 insertions(+), 2 deletions(-)
diff --git a/fs/binfmt_flat.c b/fs/binfmt_flat.c
index d04188267a..8dac70921b 100644
--- a/fs/binfmt_flat.c
+++ b/fs/binfmt_flat.c
@@ -37,6 +37,7 @@
#include <linux/init.h>
#include <linux/flat.h>
#include <linux/syscalls.h>
+#include <linux/vmalloc.h>
#include <asm/byteorder.h>
#include <asm/uaccess.h>
@@ -632,6 +633,7 @@ static int load_flat_file(struct linux_binprm * bprm,
* load it all in and treat it like a RAM load from now on
*/
if (flags & FLAT_FLAG_GZIP) {
+#ifndef CONFIG_MMU
result = decompress_exec(bprm, sizeof (struct flat_hdr),
(((char *) textpos) + sizeof (struct flat_hdr)),
(text_len + full_data
@@ -639,14 +641,52 @@ static int load_flat_file(struct linux_binprm * bprm,
0);
memmove((void *) datapos, (void *) realdatastart,
full_data);
+#else
+ /*
+ * This is used on MMU systems mainly for testing.
+ * Let's use a kernel buffer to simplify things.
+ */
+ long unz_text_len = text_len - sizeof(struct flat_hdr);
+ long unz_len = unz_text_len + full_data;
+ char *unz_data = vmalloc(unz_len);
+ if (!unz_data) {
+ result = -ENOMEM;
+ } else {
+ result = decompress_exec(bprm, sizeof(struct flat_hdr),
+ unz_data, unz_len, 0);
+ if (result == 0 &&
+ (copy_to_user((void __user *)textpos + sizeof(struct flat_hdr),
+ unz_data, unz_text_len) ||
+ copy_to_user((void __user *)datapos,
+ unz_data + unz_text_len, full_data)))
+ result = -EFAULT;
+ vfree(unz_data);
+ }
+#endif
} else if (flags & FLAT_FLAG_GZDATA) {
result = read_code(bprm->file, textpos, 0, text_len);
- if (!IS_ERR_VALUE(result))
+ if (!IS_ERR_VALUE(result)) {
+#ifndef CONFIG_MMU
result = decompress_exec(bprm, text_len, (char *) datapos,
full_data, 0);
+#else
+ char *unz_data = vmalloc(full_data);
+ if (!unz_data) {
+ result = -ENOMEM;
+ } else {
+ result = decompress_exec(bprm, text_len,
+ unz_data, full_data, 0);
+ if (result == 0 &&
+ copy_to_user((void __user *)datapos,
+ unz_data, full_data))
+ result = -EFAULT;
+ vfree(unz_data);
+ }
+#endif
+ }
}
else
-#endif
+#endif /* CONFIG_BINFMT_ZFLAT */
{
result = read_code(bprm->file, textpos, 0, text_len);
if (!IS_ERR_VALUE(result))
--
2.7.4
prev parent reply other threads:[~2016-07-20 4:21 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-20 4:20 [PATCH v3 00/12] allow BFLT executables on systems with a MMU Nicolas Pitre
2016-07-20 4:20 ` [PATCH v3 01/12] binfmt_flat: assorted cleanups Nicolas Pitre
2016-07-20 4:20 ` [PATCH v3 02/12] binfmt_flat: convert printk invocations to their modern form Nicolas Pitre
2016-07-20 4:30 ` Joe Perches
2016-07-20 5:05 ` Nicolas Pitre
2016-07-20 4:20 ` [PATCH v3 03/12] binfmt_flat: prevent kernel dammage from corrupted executable headers Nicolas Pitre
2016-07-20 4:20 ` [PATCH v3 04/12] elf_fdpic_transfer_args_to_stack(): make it generic Nicolas Pitre
2016-07-20 4:20 ` [PATCH v3 05/12] binfmt_flat: use generic transfer_args_to_stack() Nicolas Pitre
2016-07-20 4:20 ` [PATCH v3 06/12] binfmt_flat: clean up create_flat_tables() and stack accesses Nicolas Pitre
2016-07-20 4:20 ` [PATCH v3 07/12] binfmt_flat: use proper user space accessors with relocs processing code Nicolas Pitre
2016-07-20 4:20 ` [PATCH v3 08/12] binfmt_flat: use proper user space accessors with old relocs code Nicolas Pitre
2016-07-20 4:20 ` [PATCH v3 09/12] binfmt_flat: use clear_user() rather than memset() to clear .bss Nicolas Pitre
2016-07-20 7:15 ` Greg Ungerer
2016-07-20 4:20 ` [PATCH v3 10/12] binfmt_flat: update libraries' data segment pointer with userspace accessors Nicolas Pitre
2016-07-20 4:20 ` [PATCH v3 11/12] binfmt_flat: add MMU-specific support Nicolas Pitre
2016-07-20 4:20 ` Nicolas Pitre [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1468988424-32671-13-git-send-email-nicolas.pitre@linaro.org \
--to=nicolas.pitre@linaro.org \
--cc=dhowells@redhat.com \
--cc=gerg@linux-m68k.org \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=viro@zeniv.linux.org.uk \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).