svn commit: r329647 - in head/sys: compat/freebsd32 kern sys
Brooks Davis
brooks at FreeBSD.org
Tue Feb 20 18:08:59 UTC 2018
Author: brooks
Date: Tue Feb 20 18:08:57 2018
New Revision: 329647
URL: https://svnweb.freebsd.org/changeset/base/329647
Log:
Reduce duplication in dynamic syscall registration code.
Remove the unused syscall_(de)register() functions in favor of the
better documented and easier to use syscall_helper_(un)register(9)
functions.
The default and freebsd32 versions differed in which array of struct
sysents they used and a few missing updates to the 32-bit code as
features were added to the main code.
Reviewed by: cem
Sponsored by: DARPA, AFRL
Differential Revision: https://reviews.freebsd.org/D14337
Modified:
head/sys/compat/freebsd32/freebsd32_misc.c
head/sys/compat/freebsd32/freebsd32_util.h
head/sys/kern/kern_syscalls.c
head/sys/sys/sysent.h
Modified: head/sys/compat/freebsd32/freebsd32_misc.c
==============================================================================
--- head/sys/compat/freebsd32/freebsd32_misc.c Tue Feb 20 18:05:21 2018 (r329646)
+++ head/sys/compat/freebsd32/freebsd32_misc.c Tue Feb 20 18:08:57 2018 (r329647)
@@ -3089,120 +3089,24 @@ freebsd32_xxx(struct thread *td, struct freebsd32_xxx_
#endif
int
-syscall32_register(int *offset, struct sysent *new_sysent,
- struct sysent *old_sysent, int flags)
-{
-
- if ((flags & ~SY_THR_STATIC) != 0)
- return (EINVAL);
-
- if (*offset == NO_SYSCALL) {
- int i;
-
- for (i = 1; i < SYS_MAXSYSCALL; ++i)
- if (freebsd32_sysent[i].sy_call ==
- (sy_call_t *)lkmnosys)
- break;
- if (i == SYS_MAXSYSCALL)
- return (ENFILE);
- *offset = i;
- } else if (*offset < 0 || *offset >= SYS_MAXSYSCALL)
- return (EINVAL);
- else if (freebsd32_sysent[*offset].sy_call != (sy_call_t *)lkmnosys &&
- freebsd32_sysent[*offset].sy_call != (sy_call_t *)lkmressys)
- return (EEXIST);
-
- *old_sysent = freebsd32_sysent[*offset];
- freebsd32_sysent[*offset] = *new_sysent;
- atomic_store_rel_32(&freebsd32_sysent[*offset].sy_thrcnt, flags);
- return (0);
-}
-
-int
-syscall32_deregister(int *offset, struct sysent *old_sysent)
-{
-
- if (*offset == 0)
- return (0);
-
- freebsd32_sysent[*offset] = *old_sysent;
- return (0);
-}
-
-int
syscall32_module_handler(struct module *mod, int what, void *arg)
{
- struct syscall_module_data *data = (struct syscall_module_data*)arg;
- modspecific_t ms;
- int error;
- switch (what) {
- case MOD_LOAD:
- error = syscall32_register(data->offset, data->new_sysent,
- &data->old_sysent, SY_THR_STATIC_KLD);
- if (error) {
- /* Leave a mark so we know to safely unload below. */
- data->offset = NULL;
- return error;
- }
- ms.intval = *data->offset;
- MOD_XLOCK;
- module_setspecific(mod, &ms);
- MOD_XUNLOCK;
- if (data->chainevh)
- error = data->chainevh(mod, what, data->chainarg);
- return (error);
- case MOD_UNLOAD:
- /*
- * MOD_LOAD failed, so just return without calling the
- * chained handler since we didn't pass along the MOD_LOAD
- * event.
- */
- if (data->offset == NULL)
- return (0);
- if (data->chainevh) {
- error = data->chainevh(mod, what, data->chainarg);
- if (error)
- return (error);
- }
- error = syscall32_deregister(data->offset, &data->old_sysent);
- return (error);
- default:
- error = EOPNOTSUPP;
- if (data->chainevh)
- error = data->chainevh(mod, what, data->chainarg);
- return (error);
- }
+ return (kern_syscall_module_handler(freebsd32_sysent, mod, what, arg));
}
int
syscall32_helper_register(struct syscall_helper_data *sd, int flags)
{
- struct syscall_helper_data *sd1;
- int error;
- for (sd1 = sd; sd1->syscall_no != NO_SYSCALL; sd1++) {
- error = syscall32_register(&sd1->syscall_no, &sd1->new_sysent,
- &sd1->old_sysent, flags);
- if (error != 0) {
- syscall32_helper_unregister(sd);
- return (error);
- }
- sd1->registered = 1;
- }
- return (0);
+ return (kern_syscall_helper_register(freebsd32_sysent, sd, flags));
}
int
syscall32_helper_unregister(struct syscall_helper_data *sd)
{
- struct syscall_helper_data *sd1;
- for (sd1 = sd; sd1->registered != 0; sd1++) {
- syscall32_deregister(&sd1->syscall_no, &sd1->old_sysent);
- sd1->registered = 0;
- }
- return (0);
+ return (kern_syscall_helper_unregister(freebsd32_sysent, sd));
}
register_t *
Modified: head/sys/compat/freebsd32/freebsd32_util.h
==============================================================================
--- head/sys/compat/freebsd32/freebsd32_util.h Tue Feb 20 18:05:21 2018 (r329646)
+++ head/sys/compat/freebsd32/freebsd32_util.h Tue Feb 20 18:08:57 2018 (r329647)
@@ -106,9 +106,6 @@ SYSCALL32_MODULE(syscallname,
#define SYSCALL32_INIT_HELPER_COMPAT(syscallname) \
SYSCALL32_INIT_HELPER_COMPAT_F(syscallname, 0)
-int syscall32_register(int *offset, struct sysent *new_sysent,
- struct sysent *old_sysent, int flags);
-int syscall32_deregister(int *offset, struct sysent *old_sysent);
int syscall32_module_handler(struct module *mod, int what, void *arg);
int syscall32_helper_register(struct syscall_helper_data *sd, int flags);
int syscall32_helper_unregister(struct syscall_helper_data *sd);
Modified: head/sys/kern/kern_syscalls.c
==============================================================================
--- head/sys/kern/kern_syscalls.c Tue Feb 20 18:05:21 2018 (r329646)
+++ head/sys/kern/kern_syscalls.c Tue Feb 20 18:08:57 2018 (r329647)
@@ -109,8 +109,8 @@ syscall_thread_exit(struct thread *td, struct sysent *
}
int
-syscall_register(int *offset, struct sysent *new_sysent,
- struct sysent *old_sysent, int flags)
+kern_syscall_register(struct sysent *sysents, int *offset,
+ struct sysent *new_sysent, struct sysent *old_sysent, int flags)
{
int i;
@@ -119,53 +119,62 @@ syscall_register(int *offset, struct sysent *new_sysen
if (*offset == NO_SYSCALL) {
for (i = 1; i < SYS_MAXSYSCALL; ++i)
- if (sysent[i].sy_call == (sy_call_t *)lkmnosys)
+ if (sysents[i].sy_call == (sy_call_t *)lkmnosys)
break;
if (i == SYS_MAXSYSCALL)
return (ENFILE);
*offset = i;
} else if (*offset < 0 || *offset >= SYS_MAXSYSCALL)
return (EINVAL);
- else if (sysent[*offset].sy_call != (sy_call_t *)lkmnosys &&
- sysent[*offset].sy_call != (sy_call_t *)lkmressys)
+ else if (sysents[*offset].sy_call != (sy_call_t *)lkmnosys &&
+ sysents[*offset].sy_call != (sy_call_t *)lkmressys)
return (EEXIST);
- KASSERT(sysent[*offset].sy_thrcnt == SY_THR_ABSENT,
+ KASSERT(sysents[*offset].sy_thrcnt == SY_THR_ABSENT,
("dynamic syscall is not protected"));
- *old_sysent = sysent[*offset];
+ *old_sysent = sysents[*offset];
new_sysent->sy_thrcnt = SY_THR_ABSENT;
- sysent[*offset] = *new_sysent;
- atomic_store_rel_32(&sysent[*offset].sy_thrcnt, flags);
+ sysents[*offset] = *new_sysent;
+ atomic_store_rel_32(&sysents[*offset].sy_thrcnt, flags);
return (0);
}
int
-syscall_deregister(int *offset, struct sysent *old_sysent)
+kern_syscall_deregister(struct sysent *sysents, int offset,
+ const struct sysent *old_sysent)
{
struct sysent *se;
- if (*offset == 0)
+ if (offset == 0)
return (0); /* XXX? */
- se = &sysent[*offset];
+ se = &sysents[offset];
if ((se->sy_thrcnt & SY_THR_STATIC) != 0)
return (EINVAL);
syscall_thread_drain(se);
- sysent[*offset] = *old_sysent;
+ sysent[offset] = *old_sysent;
return (0);
}
int
syscall_module_handler(struct module *mod, int what, void *arg)
{
+
+ return (kern_syscall_module_handler(sysent, mod, what, arg));
+}
+
+int
+kern_syscall_module_handler(struct sysent *sysents, struct module *mod,
+ int what, void *arg)
+{
struct syscall_module_data *data = arg;
modspecific_t ms;
int error;
switch (what) {
case MOD_LOAD:
- error = syscall_register(data->offset, data->new_sysent,
- &data->old_sysent, data->flags);
+ error = kern_syscall_register(sysents, data->offset,
+ data->new_sysent, &data->old_sysent, data->flags);
if (error) {
/* Leave a mark so we know to safely unload below. */
data->offset = NULL;
@@ -191,7 +200,8 @@ syscall_module_handler(struct module *mod, int what, v
if (error)
return error;
}
- error = syscall_deregister(data->offset, &data->old_sysent);
+ error = kern_syscall_deregister(sysents, *data->offset,
+ &data->old_sysent);
return (error);
default:
if (data->chainevh)
@@ -205,14 +215,22 @@ syscall_module_handler(struct module *mod, int what, v
int
syscall_helper_register(struct syscall_helper_data *sd, int flags)
{
+
+ return (kern_syscall_helper_register(sysent, sd, flags));
+}
+
+int
+kern_syscall_helper_register(struct sysent *sysents,
+ struct syscall_helper_data *sd, int flags)
+{
struct syscall_helper_data *sd1;
int error;
for (sd1 = sd; sd1->syscall_no != NO_SYSCALL; sd1++) {
- error = syscall_register(&sd1->syscall_no, &sd1->new_sysent,
- &sd1->old_sysent, flags);
+ error = kern_syscall_register(sysents, &sd1->syscall_no,
+ &sd1->new_sysent, &sd1->old_sysent, flags);
if (error != 0) {
- syscall_helper_unregister(sd);
+ kern_syscall_helper_unregister(sysents, sd);
return (error);
}
sd1->registered = 1;
@@ -223,10 +241,19 @@ syscall_helper_register(struct syscall_helper_data *sd
int
syscall_helper_unregister(struct syscall_helper_data *sd)
{
+
+ return (kern_syscall_helper_unregister(sysent, sd));
+}
+
+int
+kern_syscall_helper_unregister(struct sysent *sysents,
+ struct syscall_helper_data *sd)
+{
struct syscall_helper_data *sd1;
for (sd1 = sd; sd1->registered != 0; sd1++) {
- syscall_deregister(&sd1->syscall_no, &sd1->old_sysent);
+ kern_syscall_deregister(sysents, sd1->syscall_no,
+ &sd1->old_sysent);
sd1->registered = 0;
}
return (0);
Modified: head/sys/sys/sysent.h
==============================================================================
--- head/sys/sys/sysent.h Tue Feb 20 18:05:21 2018 (r329646)
+++ head/sys/sys/sysent.h Tue Feb 20 18:08:57 2018 (r329647)
@@ -262,12 +262,20 @@ struct syscall_helper_data {
.syscall_no = NO_SYSCALL \
}
-int syscall_register(int *offset, struct sysent *new_sysent,
- struct sysent *old_sysent, int flags);
-int syscall_deregister(int *offset, struct sysent *old_sysent);
int syscall_module_handler(struct module *mod, int what, void *arg);
int syscall_helper_register(struct syscall_helper_data *sd, int flags);
int syscall_helper_unregister(struct syscall_helper_data *sd);
+/* Implementation, exposed for COMPAT code */
+int kern_syscall_register(struct sysent *sysents, int *offset,
+ struct sysent *new_sysent, struct sysent *old_sysent, int flags);
+int kern_syscall_deregister(struct sysent *sysents, int offset,
+ const struct sysent *old_sysent);
+int kern_syscall_module_handler(struct sysent *sysents,
+ struct module *mod, int what, void *arg);
+int kern_syscall_helper_register(struct sysent *sysents,
+ struct syscall_helper_data *sd, int flags);
+int kern_syscall_helper_unregister(struct sysent *sysents,
+ struct syscall_helper_data *sd);
struct proc;
const char *syscallname(struct proc *p, u_int code);
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