The lseek(2), mmap(2), truncate(2), ftruncate(2), pread(2), and

pwrite(2) syscalls are wrapped to provide compatibility with pre-7.x
kernels which required padding before the off_t parameter.  The
fcntl(2) contains compatibility code to handle kernels before the
struct flock was changed during the 8.x CURRENT development.  The
shims were reasonable to allow easier revert to the older kernel at
that time.

Now, two or three major releases later, shims do not serve any
purpose.  Such old kernels cannot handle current libc, so revert the
compatibility code.

Make padded syscalls support conditional under the COMPAT6 config
option.  For COMPAT32, the syscalls were under COMPAT6 already.

Remove WITHOUT_SYSCALL_COMPAT build option, which only purpose was to
(partially) disable the removed shims.

Reviewed by:	jhb, imp (previous versions)
Discussed with:	peter
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week

4 files changed, 16 insertions, 6 deletions

diff --git a/sys/kern/sys_generic.c b/sys/kern/sys_generic.c
index 8fc1db945375..213801aa2cee 100644
--- a/sys/kern/sys_generic.c
+++ b/sys/kern/sys_generic.c
@@ -219,6 +219,7 @@ sys_pread(td, uap)
 	return(error);
 }
 
+#if defined(COMPAT_FREEBSD6)
 int
 freebsd6_pread(td, uap)
 	struct thread *td;
@@ -232,6 +233,7 @@ freebsd6_pread(td, uap)
 	oargs.offset = uap->offset;
 	return (sys_pread(td, &oargs));
 }
+#endif
 
 /*
  * Scatter read system call.
@@ -430,6 +432,7 @@ sys_pwrite(td, uap)
 	return(error);
 }
 
+#if defined(COMPAT_FREEBSD6)
 int
 freebsd6_pwrite(td, uap)
 	struct thread *td;
@@ -443,6 +446,7 @@ freebsd6_pwrite(td, uap)
 	oargs.offset = uap->offset;
 	return (sys_pwrite(td, &oargs));
 }
+#endif
 
 /*
  * Gather write system call.
diff --git a/sys/kern/syscalls.master b/sys/kern/syscalls.master
index 09d38d40101a..9873868fbbf6 100644
--- a/sys/kern/syscalls.master
+++ b/sys/kern/syscalls.master
@@ -342,9 +342,9 @@
 				    int a4); }
 ; XXX should be	{ int shmsys(int which, ...); }
 172	AUE_NULL	UNIMPL	nosys
-173	AUE_PREAD	STD	{ ssize_t freebsd6_pread(int fd, void *buf, \
+173	AUE_PREAD	COMPAT6	{ ssize_t pread(int fd, void *buf, \
 				    size_t nbyte, int pad, off_t offset); }
-174	AUE_PWRITE	STD	{ ssize_t freebsd6_pwrite(int fd, \
+174	AUE_PWRITE	COMPAT6	{ ssize_t pwrite(int fd, \
 				    const void *buf, \
 				    size_t nbyte, int pad, off_t offset); }
 175	AUE_NULL	STD	{ int setfib(int fibnum); }
@@ -376,16 +376,16 @@
 				    __setrlimit_args int
 196	AUE_GETDIRENTRIES	STD	{ int getdirentries(int fd, char *buf, \
 				    u_int count, long *basep); }
-197	AUE_MMAP	STD	{ caddr_t freebsd6_mmap(caddr_t addr, \
+197	AUE_MMAP	COMPAT6	{ caddr_t mmap(caddr_t addr, \
 				    size_t len, int prot, int flags, int fd, \
 				    int pad, off_t pos); }
 198	AUE_NULL	NOPROTO	{ int nosys(void); } __syscall \
 				    __syscall_args int
-199	AUE_LSEEK	STD	{ off_t freebsd6_lseek(int fd, int pad, \
+199	AUE_LSEEK	COMPAT6	{ off_t lseek(int fd, int pad, \
 				    off_t offset, int whence); }
-200	AUE_TRUNCATE	STD	{ int freebsd6_truncate(char *path, int pad, \
+200	AUE_TRUNCATE	COMPAT6	{ int truncate(char *path, int pad, \
 				    off_t length); }
-201	AUE_FTRUNCATE	STD	{ int freebsd6_ftruncate(int fd, int pad, \
+201	AUE_FTRUNCATE	COMPAT6	{ int ftruncate(int fd, int pad, \
 				    off_t length); }
 202	AUE_SYSCTL	STD	{ int __sysctl(int *name, u_int namelen, \
 				    void *old, size_t *oldlenp, void *new, \
diff --git a/sys/kern/vfs_syscalls.c b/sys/kern/vfs_syscalls.c
index 8c8ca3165c2c..c5c479dcf270 100644
--- a/sys/kern/vfs_syscalls.c
+++ b/sys/kern/vfs_syscalls.c
@@ -1933,6 +1933,7 @@ olseek(td, uap)
 }
 #endif /* COMPAT_43 */
 
+#if defined(COMPAT_FREEBSD6)
 /* Version with the 'pad' argument */
 int
 freebsd6_lseek(td, uap)
@@ -1946,6 +1947,7 @@ freebsd6_lseek(td, uap)
 	ouap.whence = uap->whence;
 	return (sys_lseek(td, &ouap));
 }
+#endif
 
 /*
  * Check access permissions using passed credentials.
@@ -3423,6 +3425,7 @@ otruncate(td, uap)
 }
 #endif /* COMPAT_43 */
 
+#if defined(COMPAT_FREEBSD6)
 /* Versions with the pad argument */
 int
 freebsd6_truncate(struct thread *td, struct freebsd6_truncate_args *uap)
@@ -3443,6 +3446,7 @@ freebsd6_ftruncate(struct thread *td, struct freebsd6_ftruncate_args *uap)
 	ouap.length = uap->length;
 	return (sys_ftruncate(td, &ouap));
 }
+#endif
 
 /*
  * Sync an open file.
diff --git a/sys/vm/vm_mmap.c b/sys/vm/vm_mmap.c
index a9ff2482b9cd..02634d6e55f7 100644
--- a/sys/vm/vm_mmap.c
+++ b/sys/vm/vm_mmap.c
@@ -462,6 +462,7 @@ done:
 	return (error);
 }
 
+#if defined(COMPAT_FREEBSD6)
 int
 freebsd6_mmap(struct thread *td, struct freebsd6_mmap_args *uap)
 {
@@ -475,6 +476,7 @@ freebsd6_mmap(struct thread *td, struct freebsd6_mmap_args *uap)
 	oargs.pos = uap->pos;
 	return (sys_mmap(td, &oargs));
 }
+#endif
 
 #ifdef COMPAT_43
 #ifndef _SYS_SYSPROTO_H_