1 /* Copyright (C) 1995-2023 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