[PATCH] let binfmt_misc optionally preserve argv[1]

Bjorn Helgaas (bjorn_helgaas@hp.com)
Mon, 16 Dec 2002 12:17:54 -0700


[This patch applies to 2.4.20 and is due to David Mosberger]

This makes it possible for binfmt_misc to optionally preserve the
contents of argv[1]. This is needed for building accurate simulators
which are invoked via binfmt_misc. I had brought up this patch a while
ago (see URL below) and there was no negative feedback (OK, there was no
feedback at all... ;-).

The patch is trivial and the new behavior is triggered only if the
letter "P" (for "preserve") is appended to the binfmt_misc registration
string, so it shold be completely safe.

http://groups.google.com/groups?q=mosberger+binfmt_misc&hl=en&lr=&ie=UTF-8&oe=UTF-8&selm=200209092241.g89MfPS5001013%40napali.hpl.hp.com&rnum=1

diff -Nru a/fs/binfmt_misc.c b/fs/binfmt_misc.c
--- a/fs/binfmt_misc.c Mon Dec 16 12:06:58 2002
+++ b/fs/binfmt_misc.c Mon Dec 16 12:06:58 2002
@@ -35,6 +35,7 @@
static int enabled = 1;

enum {Enabled, Magic};
+#define MISC_FMT_PRESERVE_ARGV0 (1<<31)

typedef struct {
struct list_head list;
@@ -121,7 +122,9 @@
bprm->file = NULL;

/* Build args for interpreter */
- remove_arg_zero(bprm);
+ if (!(fmt->flags & MISC_FMT_PRESERVE_ARGV0)) {
+ remove_arg_zero(bprm);
+ }
retval = copy_strings_kernel(1, &bprm->filename, bprm);
if (retval < 0) goto _ret;
bprm->argc++;
@@ -286,6 +289,11 @@
*p++ = '\0';
if (!e->interpreter[0])
goto Einval;
+
+ if (*p == 'P') {
+ p++;
+ e->flags |= MISC_FMT_PRESERVE_ARGV0;
+ }

if (*p == '\n')
p++;

-
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