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binfmt_flat: allow compressed flat binary format to work on MMU systems 

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>
Signed-off-by: Greg Ungerer <gerg@linux-m68k.org>
This commit is contained in:
Nicolas Pitre 2016-07-24 11:30:26 -04:00 committed by Greg Ungerer
parent 015feacf93
commit 472f95f32d
1 changed files with 42 additions and 2 deletions
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44
fs/binfmt_flat.c
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@ -34,6 +34,7 @@
#include <linux/init.h>
#include <linux/flat.h>
#include <linux/uaccess.h>
#include <linux/vmalloc.h>
#include <asm/byteorder.h>
#include <asm/unaligned.h>
@ -628,6 +629,7 @@ 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
@ -635,13 +637,51 @@ 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
#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 /* CONFIG_BINFMT_ZFLAT */
{
result = read_code(bprm->file, textpos, 0, text_len);
if (!IS_ERR_VALUE(result))