sysdeps/unix/sysv/linux/shmctl.c

   1 /* Copyright (C) 1995-2024 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, see
  16    <https://www.gnu.org/licenses/>.  */
  17
  18 #include <sys/shm.h>
  19 #include <stdarg.h>
  20 #include <ipc_priv.h>
  21 #include <sysdep.h>
  22 #include <shlib-compat.h>
  23 #include <errno.h>
  24 #include <linux/posix_types.h>  /* For __kernel_mode_t.  */
  25
  26 /* POSIX states ipc_perm mode should have type of mode_t.  */
  27 _Static_assert (sizeof ((struct shmid_ds){0}.shm_perm.mode)
  28                 == sizeof (mode_t),
  29                 "sizeof (shmid_ds.shm_perm.mode) != sizeof (mode_t)");
  30
  31 #if __IPC_TIME64 == 0
  32 typedef struct shmid_ds shmctl_arg_t;
  33 #else
  34 # include <struct_kernel_shmid64_ds.h>
  35
  36 static void
  37 shmid64_to_kshmid64 (const struct __shmid64_ds *shmid64,
  38                      struct kernel_shmid64_ds *kshmid)
  39 {
  40   kshmid->shm_perm       = shmid64->shm_perm;
  41   kshmid->shm_segsz      = shmid64->shm_segsz;
  42   kshmid->shm_atime      = shmid64->shm_atime;
  43   kshmid->shm_atime_high = shmid64->shm_atime >> 32;
  44   kshmid->shm_dtime      = shmid64->shm_dtime;
  45   kshmid->shm_dtime_high = shmid64->shm_dtime >> 32;
  46   kshmid->shm_ctime      = shmid64->shm_ctime;
  47   kshmid->shm_ctime_high = shmid64->shm_ctime >> 32;
  48   kshmid->shm_cpid       = shmid64->shm_cpid;
  49   kshmid->shm_lpid       = shmid64->shm_lpid;
  50   kshmid->shm_nattch     = shmid64->shm_nattch;
  51 }
  52
  53 static void
  54 kshmid64_to_shmid64 (const struct kernel_shmid64_ds *kshmid,
  55                      struct __shmid64_ds *shmid64)
  56 {
  57   shmid64->shm_perm   = kshmid->shm_perm;
  58   shmid64->shm_segsz  = kshmid->shm_segsz;
  59   shmid64->shm_atime  = kshmid->shm_atime
  60                         | ((__time64_t) kshmid->shm_atime_high << 32);
  61   shmid64->shm_dtime  = kshmid->shm_dtime
  62                         | ((__time64_t) kshmid->shm_dtime_high << 32);
  63   shmid64->shm_ctime  = kshmid->shm_ctime
  64                         | ((__time64_t) kshmid->shm_ctime_high << 32);
  65   shmid64->shm_cpid   = kshmid->shm_cpid;
  66   shmid64->shm_lpid   = kshmid->shm_lpid;
  67   shmid64->shm_nattch = kshmid->shm_nattch;
  68 }
  69
  70 typedef struct kernel_shmid64_ds shmctl_arg_t;
  71 #endif
  72
  73 static int
  74 shmctl_syscall (int shmid, int cmd, shmctl_arg_t *buf)
  75 {
  76 #ifdef __ASSUME_DIRECT_SYSVIPC_SYSCALLS
  77   return INLINE_SYSCALL_CALL (shmctl, shmid, cmd | __IPC_64, buf);
  78 #else
  79   return INLINE_SYSCALL_CALL (ipc, IPCOP_shmctl, shmid, cmd | __IPC_64, 0,
  80                               buf);
  81 #endif
  82 }
  83
  84 /* Provide operations to control over shared memory segments.  */
  85 int
  86 __shmctl64 (int shmid, int cmd, struct __shmid64_ds *buf)
  87 {
  88 #if IPC_CTL_NEED_TRANSLATION
  89 # if __IPC_TIME64
  90   struct kernel_shmid64_ds kshmid, *arg = NULL;
  91 # else
  92   shmctl_arg_t *arg;
  93 # endif
  94
  95   /* Some applications pass the __IPC_64 flag in cmd, to invoke
  96      previously unsupported commands back when there was no EINVAL
  97      error checking in glibc.  Mask the flag for the switch statements
  98      below.  shmctl_syscall adds back the __IPC_64 flag for the actual
  99      system call.  */
 100   cmd &= ~__IPC_64;
 101
 102   switch (cmd)
 103     {
 104     case IPC_RMID:
 105     case SHM_LOCK:
 106     case SHM_UNLOCK:
 107       arg = NULL;
 108       break;
 109
 110     case IPC_SET:
 111     case IPC_STAT:
 112     case SHM_STAT:
 113     case SHM_STAT_ANY:
 114 # if __IPC_TIME64
 115       if (buf != NULL)
 116         {
 117           shmid64_to_kshmid64 (buf, &kshmid);
 118           arg = &kshmid;
 119         }
 120 #  ifdef __ASSUME_SYSVIPC_BROKEN_MODE_T
 121       if (cmd == IPC_SET)
 122         arg->shm_perm.mode *= 0x10000U;
 123 #  endif
 124 # else
 125       arg = buf;
 126 # endif
 127       break;
 128
 129     case IPC_INFO:
 130     case SHM_INFO:
 131       /* This is a Linux extension where kernel expects either a
 132          'struct shminfo' (IPC_INFO) or 'struct shm_info' (SHM_INFO).  */
 133       arg = (__typeof__ (arg)) buf;
 134       break;
 135
 136     default:
 137       __set_errno (EINVAL);
 138       return -1;
 139     }
 140
 141
 142   int ret = shmctl_syscall (shmid, cmd, arg);
 143   if (ret < 0)
 144     return ret;
 145
 146   switch (cmd)
 147     {
 148       case IPC_STAT:
 149       case SHM_STAT:
 150       case SHM_STAT_ANY:
 151 # ifdef __ASSUME_SYSVIPC_BROKEN_MODE_T
 152         arg->shm_perm.mode >>= 16;
 153 # else
 154       /* Old Linux kernel versions might not clear the mode padding.  */
 155       if (sizeof ((struct shmid_ds){0}.shm_perm.mode)
 156           != sizeof (__kernel_mode_t))
 157         arg->shm_perm.mode &= 0xFFFF;
 158 # endif
 159
 160 # if __IPC_TIME64
 161       kshmid64_to_shmid64 (arg, buf);
 162 # endif
 163     }
 164
 165   return ret;
 166
 167 #else /* !IPC_CTL_NEED_TRANSLATION */
 168   return shmctl_syscall (shmid, cmd, buf);
 169 #endif
 170 }
 171 #if __TIMESIZE != 64
 172 libc_hidden_def (__shmctl64)
 173
 174 static void
 175 shmid_to_shmid64 (struct __shmid64_ds *shm64, const struct shmid_ds *shm)
 176 {
 177   shm64->shm_perm   = shm->shm_perm;
 178   shm64->shm_segsz  = shm->shm_segsz;
 179   shm64->shm_atime  = shm->shm_atime
 180                       | ((__time64_t) shm->__shm_atime_high << 32);
 181   shm64->shm_dtime  = shm->shm_dtime
 182                       | ((__time64_t) shm->__shm_dtime_high << 32);
 183   shm64->shm_ctime  = shm->shm_ctime
 184                       | ((__time64_t) shm->__shm_ctime_high << 32);
 185   shm64->shm_cpid   = shm->shm_cpid;
 186   shm64->shm_lpid   = shm->shm_lpid;
 187   shm64->shm_nattch = shm->shm_nattch;
 188 }
 189
 190 static void
 191 shmid64_to_shmid (struct shmid_ds *shm, const struct __shmid64_ds *shm64)
 192 {
 193   shm->shm_perm         = shm64->shm_perm;
 194   shm->shm_segsz        = shm64->shm_segsz;
 195   shm->shm_atime        = shm64->shm_atime;
 196   shm->__shm_atime_high = 0;
 197   shm->shm_dtime        = shm64->shm_dtime;
 198   shm->__shm_dtime_high = 0;
 199   shm->shm_ctime        = shm64->shm_ctime;
 200   shm->__shm_ctime_high = 0;
 201   shm->shm_cpid         = shm64->shm_cpid;
 202   shm->shm_lpid         = shm64->shm_lpid;
 203   shm->shm_nattch       = shm64->shm_nattch;
 204 }
 205
 206 int
 207 __shmctl (int shmid, int cmd, struct shmid_ds *buf)
 208 {
 209   struct __shmid64_ds shmid64, *buf64 = NULL;
 210   if (buf != NULL)
 211     {
 212       /* This is a Linux extension where kernel expects either a
 213          'struct shminfo' (IPC_INFO) or 'struct shm_info' (SHM_INFO).  */
 214       if (cmd == IPC_INFO || cmd == SHM_INFO)
 215         buf64 = (struct __shmid64_ds *) buf;
 216       else
 217         {
 218           shmid_to_shmid64 (&shmid64, buf);
 219           buf64 = &shmid64;
 220         }
 221     }
 222
 223   int ret = __shmctl64 (shmid, cmd, buf64);
 224   if (ret < 0)
 225     return ret;
 226
 227   switch (cmd)
 228     {
 229       case IPC_STAT:
 230       case SHM_STAT:
 231       case SHM_STAT_ANY:
 232         shmid64_to_shmid (buf, buf64);
 233     }
 234
 235   return ret;
 236 }
 237 #endif
 238
 239 #ifndef DEFAULT_VERSION
 240 # ifndef __ASSUME_SYSVIPC_BROKEN_MODE_T
 241 #  define DEFAULT_VERSION GLIBC_2_2
 242 # else
 243 #  define DEFAULT_VERSION GLIBC_2_31
 244 # endif
 245 #endif
 246
 247 versioned_symbol (libc, __shmctl, shmctl, DEFAULT_VERSION);
 248
 249 #if defined __ASSUME_SYSVIPC_BROKEN_MODE_T \
 250     && SHLIB_COMPAT (libc, GLIBC_2_2, GLIBC_2_31)
 251 int
 252 attribute_compat_text_section
 253 __shmctl_mode16 (int shmid, int cmd, struct shmid_ds *buf)
 254 {
 255   return shmctl_syscall (shmid, cmd, (shmctl_arg_t *) buf);
 256 }
 257 compat_symbol (libc, __shmctl_mode16, shmctl, GLIBC_2_2);
 258 #endif
 259
 260 #if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_2)
 261 struct __old_shmid_ds
 262 {
 263   struct __old_ipc_perm shm_perm;       /* operation permission struct */
 264   int shm_segsz;                        /* size of segment in bytes */
 265   __time_t shm_atime;                   /* time of last shmat() */
 266   __time_t shm_dtime;                   /* time of last shmdt() */
 267   __time_t shm_ctime;                   /* time of last change by shmctl() */
 268   __ipc_pid_t shm_cpid;                 /* pid of creator */
 269   __ipc_pid_t shm_lpid;                 /* pid of last shmop */
 270   unsigned short int shm_nattch;        /* number of current attaches */
 271   unsigned short int __shm_npages;      /* size of segment (pages) */
 272   unsigned long int *__shm_pages;       /* array of ptrs to frames -> SHMMAX */
 273   struct vm_area_struct *__attaches;    /* descriptors for attaches */
 274 };
 275
 276 int
 277 attribute_compat_text_section
 278 __old_shmctl (int shmid, int cmd, struct __old_shmid_ds *buf)
 279 {
 280 #if defined __ASSUME_DIRECT_SYSVIPC_SYSCALLS \
 281     && !defined __ASSUME_SYSVIPC_DEFAULT_IPC_64
 282   /* For architecture that have wire-up shmctl but also have __IPC_64 to a
 283      value different than default (0x0), it means the compat symbol used the
 284      __NR_ipc syscall.  */
 285   return INLINE_SYSCALL_CALL (shmctl, shmid, cmd, buf);
 286 #else
 287   return INLINE_SYSCALL_CALL (ipc, IPCOP_shmctl, shmid, cmd, 0, buf);
 288 #endif
 289 }
 290 compat_symbol (libc, __old_shmctl, shmctl, GLIBC_2_0);
 291 #endif