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Set cwd to '/' for the process executing insmod.

Browse Source 
Ricardo has pointed out that under Solaris the cwd is set to '/'
during module load, while under Linux it is set to the callers cwd.
To handle this cleanly I've reworked the module *_init()/_exit()
macros so they call a *_setup()/_cleanup() function when any SPL
dependent module is loaded or unloaded.  This gives us a chance to
perform any needed modification of the process, in this case changing
the cwd.  It also handily provides a way to avoid creating wrapper
init()/exit() functions because the Solaris and Linux prototypes
differ slightly.  All dependent modules should now call the spl
helper macros spl_module_{init,exit}() instead of the native linux
versions.

Unfortunately, it appears that under Linux there has been no consistent
API in the kernel to set the cwd in a module.  Because of this I have
had to add more autoconf magic than I'd like.  However, what I have
done is correct and has been tested on RHEL5, SLES11, FC11, and CHAOS
kernels.

In addition, I have change the rootdir type from a 'void *' to the
correct 'vnode_t *' type.  And I've set rootdir to a non-NULL value.
This commit is contained in:
Brian Behlendorf 2009-10-01 16:06:15 -07:00
parent 0e77fc118e
commit 51a727e90f
10 changed files with 404 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

33
config/spl-build.m4
View File

@ -64,6 +64,8 @@ AC_DEFUN([SPL_AC_CONFIG_KERNEL], [
SPL_AC_ZONE_STAT_ITEM_INACTIVE
SPL_AC_ZONE_STAT_ITEM_ACTIVE
SPL_AC_GET_ZONE_COUNTS
SPL_AC_SET_FS_PWD
SPL_AC_2ARGS_SET_FS_PWD
SPL_AC_2ARGS_VFS_UNLINK
SPL_AC_4ARGS_VFS_RENAME
SPL_AC_CRED_STRUCT
@ -1203,6 +1205,37 @@ AC_DEFUN([SPL_AC_GET_ZONE_COUNTS], [
])
])
dnl #
dnl # Symbol available in RHEL kernels not in stock kernels.
dnl #
AC_DEFUN([SPL_AC_SET_FS_PWD], [
SPL_CHECK_SYMBOL_EXPORT(
[set_fs_pwd],
[],
[AC_DEFINE(HAVE_SET_FS_PWD, 1,
[set_fs_pwd() is available])],
[])
])
dnl #
dnl # 2.6.25 API change,
dnl # Simplied API by replacing mnt+dentry args with a single path arg.
dnl #
AC_DEFUN([SPL_AC_2ARGS_SET_FS_PWD],
[AC_MSG_CHECKING([whether set_fs_pwd() wants 2 args])
SPL_LINUX_TRY_COMPILE([
#include <linux/sched.h>
],[
set_fs_pwd(NULL, NULL);
],[
AC_MSG_RESULT(yes)
AC_DEFINE(HAVE_2ARGS_SET_FS_PWD, 1,
[set_fs_pwd() wants 2 args])
],[
AC_MSG_RESULT(no)
])
])
dnl #
dnl # SLES API change, never adopted in mainline,
dnl # Third 'struct vfsmount *' argument removed.

210
configure vendored
View File

@ -21709,6 +21709,111 @@ _ACEOF
fi
rm -Rf build
echo "$as_me:$LINENO: checking whether symbol set_fs_pwd is exported" >&5
echo $ECHO_N "checking whether symbol set_fs_pwd is exported... $ECHO_C" >&6
grep -q -E '[[:space:]]set_fs_pwd[[:space:]]' \
$LINUX_OBJ/Module*.symvers 2>/dev/null
rc=$?
if test $rc -ne 0; then
export=0
for file in ; do
grep -q -E "EXPORT_SYMBOL.*(set_fs_pwd)" \
"$LINUX_OBJ/$file" 2>/dev/null
rc=$?
if test $rc -eq 0; then
export=1
break;
fi
done
if test $export -eq 0; then
echo "$as_me:$LINENO: result: no" >&5
echo "${ECHO_T}no" >&6
else
echo "$as_me:$LINENO: result: yes" >&5
echo "${ECHO_T}yes" >&6
cat >>confdefs.h <<\_ACEOF
#define HAVE_SET_FS_PWD 1
_ACEOF
fi
else
echo "$as_me:$LINENO: result: yes" >&5
echo "${ECHO_T}yes" >&6
cat >>confdefs.h <<\_ACEOF
#define HAVE_SET_FS_PWD 1
_ACEOF
fi
echo "$as_me:$LINENO: checking whether set_fs_pwd() wants 2 args" >&5
echo $ECHO_N "checking whether set_fs_pwd() wants 2 args... $ECHO_C" >&6
cat >conftest.c <<_ACEOF
/* confdefs.h. */
_ACEOF
cat confdefs.h >>conftest.$ac_ext
cat >>conftest.$ac_ext <<_ACEOF
/* end confdefs.h. */
#include <linux/sched.h>
int
main (void)
{
set_fs_pwd(NULL, NULL);
;
return 0;
}
_ACEOF
rm -Rf build && mkdir -p build
echo "obj-m := conftest.o" >build/Makefile
if { ac_try='cp conftest.c build && make modules -C $LINUX_OBJ EXTRA_CFLAGS="-Werror-implicit-function-declaration $EXTRA_KCFLAGS" $ARCH_UM M=$PWD/build'
{ (eval echo "$as_me:$LINENO: \"$ac_try\"") >&5
(eval $ac_try) 2>&5
ac_status=$?
echo "$as_me:$LINENO: \$? = $ac_status" >&5
(exit $ac_status); }; } >/dev/null && { ac_try='test -s build/conftest.o'
{ (eval echo "$as_me:$LINENO: \"$ac_try\"") >&5
(eval $ac_try) 2>&5
ac_status=$?
echo "$as_me:$LINENO: \$? = $ac_status" >&5
(exit $ac_status); }; }; then
echo "$as_me:$LINENO: result: yes" >&5
echo "${ECHO_T}yes" >&6
cat >>confdefs.h <<\_ACEOF
#define HAVE_2ARGS_SET_FS_PWD 1
_ACEOF
else
echo "$as_me: failed program was:" >&5
sed 's/^/| /' conftest.$ac_ext >&5
echo "$as_me:$LINENO: result: no" >&5
echo "${ECHO_T}no" >&6
fi
rm -Rf build
@ -24752,6 +24857,111 @@ _ACEOF
fi
rm -Rf build
echo "$as_me:$LINENO: checking whether symbol set_fs_pwd is exported" >&5
echo $ECHO_N "checking whether symbol set_fs_pwd is exported... $ECHO_C" >&6
grep -q -E '[[:space:]]set_fs_pwd[[:space:]]' \
$LINUX_OBJ/Module*.symvers 2>/dev/null
rc=$?
if test $rc -ne 0; then
export=0
for file in ; do
grep -q -E "EXPORT_SYMBOL.*(set_fs_pwd)" \
"$LINUX_OBJ/$file" 2>/dev/null
rc=$?
if test $rc -eq 0; then
export=1
break;
fi
done
if test $export -eq 0; then
echo "$as_me:$LINENO: result: no" >&5
echo "${ECHO_T}no" >&6
else
echo "$as_me:$LINENO: result: yes" >&5
echo "${ECHO_T}yes" >&6
cat >>confdefs.h <<\_ACEOF
#define HAVE_SET_FS_PWD 1
_ACEOF
fi
else
echo "$as_me:$LINENO: result: yes" >&5
echo "${ECHO_T}yes" >&6
cat >>confdefs.h <<\_ACEOF
#define HAVE_SET_FS_PWD 1
_ACEOF
fi
echo "$as_me:$LINENO: checking whether set_fs_pwd() wants 2 args" >&5
echo $ECHO_N "checking whether set_fs_pwd() wants 2 args... $ECHO_C" >&6
cat >conftest.c <<_ACEOF
/* confdefs.h. */
_ACEOF
cat confdefs.h >>conftest.$ac_ext
cat >>conftest.$ac_ext <<_ACEOF
/* end confdefs.h. */
#include <linux/sched.h>
int
main (void)
{
set_fs_pwd(NULL, NULL);
;
return 0;
}
_ACEOF
rm -Rf build && mkdir -p build
echo "obj-m := conftest.o" >build/Makefile
if { ac_try='cp conftest.c build && make modules -C $LINUX_OBJ EXTRA_CFLAGS="-Werror-implicit-function-declaration $EXTRA_KCFLAGS" $ARCH_UM M=$PWD/build'
{ (eval echo "$as_me:$LINENO: \"$ac_try\"") >&5
(eval $ac_try) 2>&5
ac_status=$?
echo "$as_me:$LINENO: \$? = $ac_status" >&5
(exit $ac_status); }; } >/dev/null && { ac_try='test -s build/conftest.o'
{ (eval echo "$as_me:$LINENO: \"$ac_try\"") >&5
(eval $ac_try) 2>&5
ac_status=$?
echo "$as_me:$LINENO: \$? = $ac_status" >&5
(exit $ac_status); }; }; then
echo "$as_me:$LINENO: result: yes" >&5
echo "${ECHO_T}yes" >&6
cat >>confdefs.h <<\_ACEOF
#define HAVE_2ARGS_SET_FS_PWD 1
_ACEOF
else
echo "$as_me: failed program was:" >&5
sed 's/^/| /' conftest.$ac_ext >&5
echo "$as_me:$LINENO: result: no" >&5
echo "${ECHO_T}no" >&6
fi
rm -Rf build

35
include/linux/module_compat.h Normal file
View File

@ -0,0 +1,35 @@
#ifndef _SPL_MODULE_COMPAT_H
#define _SPL_MODULE_COMPAT_H
#include <linux/module.h>
#define spl_module_init(init_fn) \
static int \
spl_##init_fn(void) \
{ \
int rc; \
\
spl_setup(); \
rc = init_fn(); \
\
return rc; \
} \
\
module_init(spl_##init_fn)
#define spl_module_exit(exit_fn) \
static void \
spl_##exit_fn(void) \
{ \
int rc; \
\
rc = exit_fn(); \
spl_cleanup(); \
if (rc) \
printk(KERN_ERR "SPL: Failure %d unloading " \
"dependent module\n", rc); \
} \
\
module_exit(spl_##exit_fn)
#endif /* _SPL_MODULE_COMPAT_H */

2
include/sys/sysmacros.h
View File

@ -144,6 +144,8 @@ extern int p0;
/* Missing misc functions */
extern int highbit(unsigned long i);
extern uint32_t zone_get_hostid(void *zone);
extern void spl_setup(void);
extern void spl_cleanup(void);
#define makedevice(maj,min) makedev(maj,min)

1
include/sys/types.h
View File

@ -18,6 +18,7 @@ extern "C" {
#include <linux/workqueue_compat.h>
#include <linux/kallsyms_compat.h>
#include <linux/mutex_compat.h>
#include <linux/module_compat.h>
#ifndef HAVE_UINTPTR_T
typedef unsigned long uintptr_t;

3
include/sys/vnode.h
View File

@ -215,6 +215,7 @@ extern int vn_getattr(vnode_t *vp, vattr_t *vap, int flags, void *x3, void *x4);
extern int vn_fsync(vnode_t *vp, int flags, void *x3, void *x4);
extern file_t *vn_getf(int fd);
extern void vn_releasef(int fd);
extern int vn_set_pwd(const char *filename);
int vn_init(void);
void vn_fini(void);
@ -241,7 +242,7 @@ vn_putpage(vnode_t *vp, offset_t off, ssize_t size,
#define getf vn_getf
#define releasef vn_releasef
extern void *rootdir;
extern vnode_t *rootdir;
#ifdef __cplusplus
}

26
module/spl/spl-generic.c
View File

@ -358,7 +358,8 @@ set_kallsyms_lookup_name(void)
}
#endif
static int __init spl_init(void)
static int
__init spl_init(void)
{
int rc = 0;
@ -421,7 +422,8 @@ out1:
return rc;
}
static void spl_fini(void)
static void
spl_fini(void)
{
ENTRY;
@ -436,6 +438,26 @@ static void spl_fini(void)
debug_fini();
}
/* Called when a dependent module is loaded */
void
spl_setup(void)
{
/*
* At module load time the pwd is set to '/' on a Solaris system.
* On a Linux system will be set to whatever directory the caller
* was in when executing insmod/modprobe.
*/
vn_set_pwd("/");
}
EXPORT_SYMBOL(spl_setup);
/* Called when a dependent module is unloaded */
void
spl_cleanup(void)
{
}
EXPORT_SYMBOL(spl_cleanup);
module_init(spl_init);
module_exit(spl_fini);

86
module/spl/spl-vnode.c
View File

@ -34,7 +34,7 @@
#define DEBUG_SUBSYSTEM S_VNODE
void *rootdir = NULL;
vnode_t *rootdir = (vnode_t *)0xabcd1234;
EXPORT_SYMBOL(rootdir);
static spl_kmem_cache_t *vn_cache;
@ -602,6 +602,90 @@ vn_releasef(int fd)
} /* releasef() */
EXPORT_SYMBOL(releasef);
#ifndef HAVE_SET_FS_PWD
# ifdef HAVE_2ARGS_SET_FS_PWD
/* Used from 2.6.25 - 2.6.31+ */
void
set_fs_pwd(struct fs_struct *fs, struct path *path)
{
struct path old_pwd;
write_lock(&fs->lock);
old_pwd = fs->pwd;
fs->pwd = *path;
path_get(path);
write_unlock(&fs->lock);
if (old_pwd.dentry)
path_put(&old_pwd);
}
# else
/* Used from 2.6.11 - 2.6.24 */
void
set_fs_pwd(struct fs_struct *fs, struct vfsmount *mnt, struct dentry *dentry)
{
struct dentry *old_pwd;
struct vfsmount *old_pwdmnt;
write_lock(&fs->lock);
old_pwd = fs->pwd;
old_pwdmnt = fs->pwdmnt;
fs->pwdmnt = mntget(mnt);
fs->pwd = dget(dentry);
write_unlock(&fs->lock);
if (old_pwd) {
dput(old_pwd);
mntput(old_pwdmnt);
}
}
# endif /* HAVE_2ARGS_SET_FS_PWD */
#endif /* HAVE_SET_FS_PWD */
int
vn_set_pwd(const char *filename)
{
#ifdef HAVE_2ARGS_SET_FS_PWD
struct path path;
int rc;
ENTRY;
rc = user_path_dir(filename, &path);
if (rc)
GOTO(out, rc);
rc = inode_permission(path.dentry->d_inode, MAY_EXEC | MAY_ACCESS);
if (rc)
GOTO(dput_and_out, rc);
set_fs_pwd(current->fs, &path);
dput_and_out:
path_put(&path);
#else
struct nameidata nd;
int rc;
ENTRY;
rc = __user_walk(filename,
LOOKUP_FOLLOW|LOOKUP_DIRECTORY|LOOKUP_CHDIR, &nd);
if (rc)
GOTO(out, rc);
rc = vfs_permission(&nd, MAY_EXEC);
if (rc)
GOTO(dput_and_out, rc);
set_fs_pwd(current->fs, nd.nd_mnt, nd.nd_dentry);
dput_and_out:
vn_path_release(&nd);
#endif /* HAVE_2ARGS_SET_FS_PWD */
out:
RETURN(-rc);
} /* vn_set_pwd() */
EXPORT_SYMBOL(vn_set_pwd);
static int
vn_cache_constructor(void *buf, void *cdrarg, int kmflags)
{

10
module/splat/splat-ctl.c
View File

@ -608,7 +608,7 @@ static struct cdev splat_cdev = {
.kobj = { .name = SPLAT_NAME, },
};
static int __init
static int
splat_init(void)
{
dev_t dev;
@ -667,7 +667,7 @@ error:
return rc;
}
static void
static int
splat_fini(void)
{
dev_t dev = MKDEV(SPLAT_MAJOR, 0);
@ -695,10 +695,12 @@ splat_fini(void)
ASSERT(list_empty(&splat_module_list));
printk(KERN_INFO "SPLAT: Unloaded Solaris Porting LAyer "
"Tests v%s\n", SPL_META_VERSION);
return 0;
}
module_init(splat_init);
module_exit(splat_fini);
spl_module_init(splat_init);
spl_module_exit(splat_fini);
MODULE_AUTHOR("Lawrence Livermore National Labs");
MODULE_DESCRIPTION("Solaris Porting LAyer Tests");

6
spl_config.h.in
View File

@ -12,6 +12,9 @@
/* register_sysctl_table() wants 2 args */
#undef HAVE_2ARGS_REGISTER_SYSCTL
/* set_fs_pwd() wants 2 args */
#undef HAVE_2ARGS_SET_FS_PWD
/* vfs_unlink() wants 2 args */
#undef HAVE_2ARGS_VFS_UNLINK
@ -120,6 +123,9 @@
/* __put_task_struct() is available */
#undef HAVE_PUT_TASK_STRUCT
/* set_fs_pwd() is available */
#undef HAVE_SET_FS_PWD
/* set_normalized_timespec() is available as export */
#undef HAVE_SET_NORMALIZED_TIMESPEC_EXPORT