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ipc: rename old-style shmctl/semctl/msgctl syscalls

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The behavior of these system calls is slightly different between
architectures, as determined by the CONFIG_ARCH_WANT_IPC_PARSE_VERSION
symbol. Most architectures that implement the split IPC syscalls don't set
that symbol and only get the modern version, but alpha, arm, microblaze,
mips-n32, mips-n64 and xtensa expect the caller to pass the IPC_64 flag.

For the architectures that so far only implement sys_ipc(), i.e. m68k,
mips-o32, powerpc, s390, sh, sparc, and x86-32, we want the new behavior
when adding the split syscalls, so we need to distinguish between the
two groups of architectures.

The method I picked for this distinction is to have a separate system call
entry point: sys_old_*ctl() now uses ipc_parse_version, while sys_*ctl()
does not. The system call tables of the five architectures are changed
accordingly.

As an additional benefit, we no longer need the configuration specific
definition for ipc_parse_version(), it always does the same thing now,
but simply won't get called on architectures with the modern interface.

A small downside is that on architectures that do set
ARCH_WANT_IPC_PARSE_VERSION, we now have an extra set of entry points
that are never called. They only add a few bytes of bloat, so it seems
better to keep them compared to adding yet another Kconfig symbol.
I considered adding new syscall numbers for the IPC_64 variants for
consistency, but decided against that for now.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
This commit is contained in:
Arnd Bergmann
2018-12-31 22:22:40 +01:00
parent 73a66023c9
commit 275f22148e
14 changed files with 137 additions and 62 deletions
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40
ipc/shm.c
View File

@@ -1137,16 +1137,15 @@ out_unlock1:
return err;
}
long ksys_shmctl(int shmid, int cmd, struct shmid_ds __user *buf)
static long ksys_shmctl(int shmid, int cmd, struct shmid_ds __user *buf, int version)
{
int err, version;
int err;
struct ipc_namespace *ns;
struct shmid64_ds sem64;
if (cmd < 0 || shmid < 0)
return -EINVAL;
version = ipc_parse_version(&cmd);
ns = current->nsproxy->ipc_ns;
switch (cmd) {
@@ -1194,9 +1193,23 @@ long ksys_shmctl(int shmid, int cmd, struct shmid_ds __user *buf)
SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, struct shmid_ds __user *, buf)
{
return ksys_shmctl(shmid, cmd, buf);
return ksys_shmctl(shmid, cmd, buf, IPC_64);
}
#ifdef CONFIG_ARCH_WANT_IPC_PARSE_VERSION
long ksys_old_shmctl(int shmid, int cmd, struct shmid_ds __user *buf)
{
int version = ipc_parse_version(&cmd);
return ksys_shmctl(shmid, cmd, buf, version);
}
SYSCALL_DEFINE3(old_shmctl, int, shmid, int, cmd, struct shmid_ds __user *, buf)
{
return ksys_old_shmctl(shmid, cmd, buf);
}
#endif
#ifdef CONFIG_COMPAT
struct compat_shmid_ds {
@@ -1319,11 +1332,10 @@ static int copy_compat_shmid_from_user(struct shmid64_ds *out, void __user *buf,
}
}
long compat_ksys_shmctl(int shmid, int cmd, void __user *uptr)
long compat_ksys_shmctl(int shmid, int cmd, void __user *uptr, int version)
{
struct ipc_namespace *ns;
struct shmid64_ds sem64;
int version = compat_ipc_parse_version(&cmd);
int err;
ns = current->nsproxy->ipc_ns;
@@ -1378,8 +1390,22 @@ long compat_ksys_shmctl(int shmid, int cmd, void __user *uptr)
COMPAT_SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, void __user *, uptr)
{
return compat_ksys_shmctl(shmid, cmd, uptr);
return compat_ksys_shmctl(shmid, cmd, uptr, IPC_64);
}
#ifdef CONFIG_ARCH_WANT_COMPAT_IPC_PARSE_VERSION
long compat_ksys_old_shmctl(int shmid, int cmd, void __user *uptr)
{
int version = compat_ipc_parse_version(&cmd);
return compat_ksys_shmctl(shmid, cmd, uptr, version);
}
COMPAT_SYSCALL_DEFINE3(old_shmctl, int, shmid, int, cmd, void __user *, uptr)
{
return compat_ksys_old_shmctl(shmid, cmd, uptr);
}
#endif
#endif
/*