glibc/sysdeps/unix/sysv/linux/shmctl.c

292 lines
8.3 KiB
C

/* Copyright (C) 1995-2024 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
#include <sys/shm.h>
#include <stdarg.h>
#include <ipc_priv.h>
#include <sysdep.h>
#include <shlib-compat.h>
#include <errno.h>
#include <linux/posix_types.h> /* For __kernel_mode_t. */
/* POSIX states ipc_perm mode should have type of mode_t. */
_Static_assert (sizeof ((struct shmid_ds){0}.shm_perm.mode)
== sizeof (mode_t),
"sizeof (shmid_ds.shm_perm.mode) != sizeof (mode_t)");
#if __IPC_TIME64 == 0
typedef struct shmid_ds shmctl_arg_t;
#else
# include <struct_kernel_shmid64_ds.h>
static void
shmid64_to_kshmid64 (const struct __shmid64_ds *shmid64,
struct kernel_shmid64_ds *kshmid)
{
kshmid->shm_perm = shmid64->shm_perm;
kshmid->shm_segsz = shmid64->shm_segsz;
kshmid->shm_atime = shmid64->shm_atime;
kshmid->shm_atime_high = shmid64->shm_atime >> 32;
kshmid->shm_dtime = shmid64->shm_dtime;
kshmid->shm_dtime_high = shmid64->shm_dtime >> 32;
kshmid->shm_ctime = shmid64->shm_ctime;
kshmid->shm_ctime_high = shmid64->shm_ctime >> 32;
kshmid->shm_cpid = shmid64->shm_cpid;
kshmid->shm_lpid = shmid64->shm_lpid;
kshmid->shm_nattch = shmid64->shm_nattch;
}
static void
kshmid64_to_shmid64 (const struct kernel_shmid64_ds *kshmid,
struct __shmid64_ds *shmid64)
{
shmid64->shm_perm = kshmid->shm_perm;
shmid64->shm_segsz = kshmid->shm_segsz;
shmid64->shm_atime = kshmid->shm_atime
| ((__time64_t) kshmid->shm_atime_high << 32);
shmid64->shm_dtime = kshmid->shm_dtime
| ((__time64_t) kshmid->shm_dtime_high << 32);
shmid64->shm_ctime = kshmid->shm_ctime
| ((__time64_t) kshmid->shm_ctime_high << 32);
shmid64->shm_cpid = kshmid->shm_cpid;
shmid64->shm_lpid = kshmid->shm_lpid;
shmid64->shm_nattch = kshmid->shm_nattch;
}
typedef struct kernel_shmid64_ds shmctl_arg_t;
#endif
static int
shmctl_syscall (int shmid, int cmd, shmctl_arg_t *buf)
{
#ifdef __ASSUME_DIRECT_SYSVIPC_SYSCALLS
return INLINE_SYSCALL_CALL (shmctl, shmid, cmd | __IPC_64, buf);
#else
return INLINE_SYSCALL_CALL (ipc, IPCOP_shmctl, shmid, cmd | __IPC_64, 0,
buf);
#endif
}
/* Provide operations to control over shared memory segments. */
int
__shmctl64 (int shmid, int cmd, struct __shmid64_ds *buf)
{
#if IPC_CTL_NEED_TRANSLATION
# if __IPC_TIME64
struct kernel_shmid64_ds kshmid, *arg = NULL;
# else
shmctl_arg_t *arg;
# endif
/* Some applications pass the __IPC_64 flag in cmd, to invoke
previously unsupported commands back when there was no EINVAL
error checking in glibc. Mask the flag for the switch statements
below. shmctl_syscall adds back the __IPC_64 flag for the actual
system call. */
cmd &= ~__IPC_64;
switch (cmd)
{
case IPC_RMID:
case SHM_LOCK:
case SHM_UNLOCK:
arg = NULL;
break;
case IPC_SET:
case IPC_STAT:
case SHM_STAT:
case SHM_STAT_ANY:
# if __IPC_TIME64
if (buf != NULL)
{
shmid64_to_kshmid64 (buf, &kshmid);
arg = &kshmid;
}
# ifdef __ASSUME_SYSVIPC_BROKEN_MODE_T
if (cmd == IPC_SET)
arg->shm_perm.mode *= 0x10000U;
# endif
# else
arg = buf;
# endif
break;
case IPC_INFO:
case SHM_INFO:
/* This is a Linux extension where kernel expects either a
'struct shminfo' (IPC_INFO) or 'struct shm_info' (SHM_INFO). */
arg = (__typeof__ (arg)) buf;
break;
default:
__set_errno (EINVAL);
return -1;
}
int ret = shmctl_syscall (shmid, cmd, arg);
if (ret < 0)
return ret;
switch (cmd)
{
case IPC_STAT:
case SHM_STAT:
case SHM_STAT_ANY:
# ifdef __ASSUME_SYSVIPC_BROKEN_MODE_T
arg->shm_perm.mode >>= 16;
# else
/* Old Linux kernel versions might not clear the mode padding. */
if (sizeof ((struct shmid_ds){0}.shm_perm.mode)
!= sizeof (__kernel_mode_t))
arg->shm_perm.mode &= 0xFFFF;
# endif
# if __IPC_TIME64
kshmid64_to_shmid64 (arg, buf);
# endif
}
return ret;
#else /* !IPC_CTL_NEED_TRANSLATION */
return shmctl_syscall (shmid, cmd, buf);
#endif
}
#if __TIMESIZE != 64
libc_hidden_def (__shmctl64)
static void
shmid_to_shmid64 (struct __shmid64_ds *shm64, const struct shmid_ds *shm)
{
shm64->shm_perm = shm->shm_perm;
shm64->shm_segsz = shm->shm_segsz;
shm64->shm_atime = shm->shm_atime
| ((__time64_t) shm->__shm_atime_high << 32);
shm64->shm_dtime = shm->shm_dtime
| ((__time64_t) shm->__shm_dtime_high << 32);
shm64->shm_ctime = shm->shm_ctime
| ((__time64_t) shm->__shm_ctime_high << 32);
shm64->shm_cpid = shm->shm_cpid;
shm64->shm_lpid = shm->shm_lpid;
shm64->shm_nattch = shm->shm_nattch;
}
static void
shmid64_to_shmid (struct shmid_ds *shm, const struct __shmid64_ds *shm64)
{
shm->shm_perm = shm64->shm_perm;
shm->shm_segsz = shm64->shm_segsz;
shm->shm_atime = shm64->shm_atime;
shm->__shm_atime_high = 0;
shm->shm_dtime = shm64->shm_dtime;
shm->__shm_dtime_high = 0;
shm->shm_ctime = shm64->shm_ctime;
shm->__shm_ctime_high = 0;
shm->shm_cpid = shm64->shm_cpid;
shm->shm_lpid = shm64->shm_lpid;
shm->shm_nattch = shm64->shm_nattch;
}
int
__shmctl (int shmid, int cmd, struct shmid_ds *buf)
{
struct __shmid64_ds shmid64, *buf64 = NULL;
if (buf != NULL)
{
/* This is a Linux extension where kernel expects either a
'struct shminfo' (IPC_INFO) or 'struct shm_info' (SHM_INFO). */
if (cmd == IPC_INFO || cmd == SHM_INFO)
buf64 = (struct __shmid64_ds *) buf;
else
{
shmid_to_shmid64 (&shmid64, buf);
buf64 = &shmid64;
}
}
int ret = __shmctl64 (shmid, cmd, buf64);
if (ret < 0)
return ret;
switch (cmd)
{
case IPC_STAT:
case SHM_STAT:
case SHM_STAT_ANY:
shmid64_to_shmid (buf, buf64);
}
return ret;
}
#endif
#ifndef DEFAULT_VERSION
# ifndef __ASSUME_SYSVIPC_BROKEN_MODE_T
# define DEFAULT_VERSION GLIBC_2_2
# else
# define DEFAULT_VERSION GLIBC_2_31
# endif
#endif
versioned_symbol (libc, __shmctl, shmctl, DEFAULT_VERSION);
#if defined __ASSUME_SYSVIPC_BROKEN_MODE_T \
&& SHLIB_COMPAT (libc, GLIBC_2_2, GLIBC_2_31)
int
attribute_compat_text_section
__shmctl_mode16 (int shmid, int cmd, struct shmid_ds *buf)
{
return shmctl_syscall (shmid, cmd, (shmctl_arg_t *) buf);
}
compat_symbol (libc, __shmctl_mode16, shmctl, GLIBC_2_2);
#endif
#if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_2)
struct __old_shmid_ds
{
struct __old_ipc_perm shm_perm; /* operation permission struct */
int shm_segsz; /* size of segment in bytes */
__time_t shm_atime; /* time of last shmat() */
__time_t shm_dtime; /* time of last shmdt() */
__time_t shm_ctime; /* time of last change by shmctl() */
__ipc_pid_t shm_cpid; /* pid of creator */
__ipc_pid_t shm_lpid; /* pid of last shmop */
unsigned short int shm_nattch; /* number of current attaches */
unsigned short int __shm_npages; /* size of segment (pages) */
unsigned long int *__shm_pages; /* array of ptrs to frames -> SHMMAX */
struct vm_area_struct *__attaches; /* descriptors for attaches */
};
int
attribute_compat_text_section
__old_shmctl (int shmid, int cmd, struct __old_shmid_ds *buf)
{
#if defined __ASSUME_DIRECT_SYSVIPC_SYSCALLS \
&& !defined __ASSUME_SYSVIPC_DEFAULT_IPC_64
/* For architecture that have wire-up shmctl but also have __IPC_64 to a
value different than default (0x0), it means the compat symbol used the
__NR_ipc syscall. */
return INLINE_SYSCALL_CALL (shmctl, shmid, cmd, buf);
#else
return INLINE_SYSCALL_CALL (ipc, IPCOP_shmctl, shmid, cmd, 0, buf);
#endif
}
compat_symbol (libc, __old_shmctl, shmctl, GLIBC_2_0);
#endif