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Subjectbinfmt handler searching issues
A script such as

#!/bin/foo.bar
...

where /bin/foo.bar is handled by binfmt_misc, is not handled correctly i.e. the interpreter of foo.bar doesn't receive the correct arguments.

The binfmt_misc handler requires that bprm->filename is appropriately filled so that the argv[1] could be correctly passed to the interpreter.

However, binfmt_script, as it exists today doesn't populate bprm->filename correctly.

Another motivation for this patch is the output of ps. Emulators which use binfmt_misc may want to keep the output of ps consistent with native execution. This requires preserving bprm->filename. The attached patch guarantees this even if we have to go through several binfmt handlers (think of finite loops involving binfmt_script and binfmt_misc).

-Arun
--- linux/fs/exec.c- Thu Mar 13 11:42:51 2003
+++ linux/fs/exec.c Thu Mar 13 11:43:05 2003
@@ -882,6 +882,7 @@

bprm.file = file;
bprm.filename = filename;
+ bprm.interp = filename;
bprm.sh_bang = 0;
bprm.loader = 0;
bprm.exec = 0;
--- linux/fs/binfmt_script.c- Thu Mar 13 12:09:28 2003
+++ linux/fs/binfmt_script.c Thu Mar 13 12:09:46 2003
@@ -78,6 +78,8 @@
retval = copy_strings_kernel(1, &i_name, bprm);
if (retval) return retval;
bprm->argc++;
+ bprm->interp = interp;
+
/*
* OK, now restart the process with the interpreter's dentry.
*/
--- linux/include/linux/binfmts.h- Thu Mar 13 11:40:41 2003
+++ linux/include/linux/binfmts.h Thu Mar 13 11:42:05 2003
@@ -30,7 +30,10 @@
int e_uid, e_gid;
kernel_cap_t cap_inheritable, cap_permitted, cap_effective;
int argc, envc;
- char * filename; /* Name of binary */
+ char * filename; /* Name of binary as seen by procps */
+ char * interp; /* Name of the binary really executed. Most
+ of the time same as filename, but could be
+ different for binfmt_{misc,script} */
unsigned long loader, exec;
};

--- linux/fs/binfmt_script.c- Mon Mar 17 08:10:56 2003
+++ linux/fs/binfmt_script.c Mon Mar 17 08:13:07 2003
@@ -67,7 +67,7 @@
* user environment and arguments are stored.
*/
remove_arg_zero(bprm);
- retval = copy_strings_kernel(1, &bprm->filename, bprm);
+ retval = copy_strings_kernel(1, &bprm->interp, bprm);
if (retval < 0) return retval;
bprm->argc++;
if (i_arg) {
--- linux/fs/binfmt_misc.c.orig Wed Mar 19 15:45:34 2003
+++ linux/fs/binfmt_misc.c Wed Mar 19 15:49:39 2003
@@ -58,7 +58,7 @@
*/
static Node *check_file(struct linux_binprm *bprm)
{
- char *p = strrchr(bprm->filename, '.');
+ char *p = strrchr(bprm->interp, '.');
struct list_head *l;

for (l = entries.next; l != &entries; l = l->next) {
@@ -125,13 +125,13 @@
if (!(fmt->flags & MISC_FMT_PRESERVE_ARGV0)) {
remove_arg_zero(bprm);
}
- retval = copy_strings_kernel(1, &bprm->filename, bprm);
+ retval = copy_strings_kernel(1, &bprm->interp, bprm);
if (retval < 0) goto _ret;
bprm->argc++;
retval = copy_strings_kernel(1, &iname_addr, bprm);
if (retval < 0) goto _ret;
bprm->argc++;
- bprm->filename = iname; /* for binfmt_script */
+ bprm->interp = iname; /* for binfmt_script */

file = open_exec(iname);
retval = PTR_ERR(file);
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