[PATCH 03/10] binfmt_flat: use generic transfer_args_to_stack()

From: Nicolas Pitre
Date: Tue Jul 12 2016 - 17:44:09 EST


This gets rid of the rather ugly, open coded and suboptimal copy code.

Signed-off-by: Nicolas Pitre <nico@xxxxxxxxxx>
---
fs/binfmt_flat.c | 22 ++++++++++------------
1 file changed, 10 insertions(+), 12 deletions(-)

diff --git a/fs/binfmt_flat.c b/fs/binfmt_flat.c
index 085059d879..64feb873f0 100644
--- a/fs/binfmt_flat.c
+++ b/fs/binfmt_flat.c
@@ -854,10 +854,8 @@ static int load_flat_binary(struct linux_binprm * bprm)
{
struct lib_info libinfo;
struct pt_regs *regs = current_pt_regs();
- unsigned long p = bprm->p;
- unsigned long stack_len;
+ unsigned long sp, stack_len;
unsigned long start_addr;
- unsigned long *sp;
int res;
int i, j;

@@ -892,15 +890,15 @@ static int load_flat_binary(struct linux_binprm * bprm)

set_binfmt(&flat_format);

- p = ((current->mm->context.end_brk + stack_len + 3) & ~3) - 4;
- DBG_FLT("p=%lx\n", p);
+ sp = ((current->mm->context.end_brk + stack_len + 3) & ~3) - 4;
+ DBG_FLT("sp=%lx\n", sp);

- /* copy the arg pages onto the stack, this could be more efficient :-) */
- for (i = TOP_OF_ARGS - 1; i >= bprm->p; i--)
- * (char *) --p =
- ((char *) page_address(bprm->page[i/PAGE_SIZE]))[i % PAGE_SIZE];
+ /* copy the arg pages onto the stack */
+ res = transfer_args_to_stack(bprm, &sp);
+ if (res)
+ return res;

- sp = (unsigned long *) create_flat_tables(p, bprm);
+ sp = create_flat_tables(sp, bprm);

/* Fake some return addresses to ensure the call chain will
* initialise library in order for us. We are required to call
@@ -912,14 +910,14 @@ static int load_flat_binary(struct linux_binprm * bprm)
for (i = MAX_SHARED_LIBS-1; i>0; i--) {
if (libinfo.lib_list[i].loaded) {
/* Push previos first to call address */
- --sp; put_user(start_addr, sp);
+ --sp; put_user(start_addr, (unsigned long *)sp);
start_addr = libinfo.lib_list[i].entry;
}
}
#endif

/* Stash our initial stack pointer into the mm structure */
- current->mm->start_stack = (unsigned long )sp;
+ current->mm->start_stack = sp;

#ifdef FLAT_PLAT_INIT
FLAT_PLAT_INIT(regs);
--
2.7.4