/usr/include/linux/shm.h is in linux-libc-dev 3.16.56-1+deb8u1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 | #ifndef _LINUX_SHM_H_
#define _LINUX_SHM_H_
#include <linux/ipc.h>
#include <linux/errno.h>
#include <unistd.h>
/*
* SHMMNI, SHMMAX and SHMALL are default upper limits which can be
* modified by sysctl. The SHMMAX and SHMALL values have been chosen to
* be as large possible without facilitating scenarios where userspace
* causes overflows when adjusting the limits via operations of the form
* "retrieve current limit; add X; update limit". It is therefore not
* advised to make SHMMAX and SHMALL any larger. These limits are
* suitable for both 32 and 64-bit systems.
*/
#define SHMMIN 1 /* min shared seg size (bytes) */
#define SHMMNI 4096 /* max num of segs system wide */
#define SHMMAX (ULONG_MAX - (1UL << 24)) /* max shared seg size (bytes) */
#define SHMALL (ULONG_MAX - (1UL << 24)) /* max shm system wide (pages) */
#define SHMSEG SHMMNI /* max shared segs per process */
/* Obsolete, used only for backwards compatibility and libc5 compiles */
struct shmid_ds {
struct ipc_perm shm_perm; /* operation perms */
int shm_segsz; /* size of segment (bytes) */
__kernel_time_t shm_atime; /* last attach time */
__kernel_time_t shm_dtime; /* last detach time */
__kernel_time_t shm_ctime; /* last change time */
__kernel_ipc_pid_t shm_cpid; /* pid of creator */
__kernel_ipc_pid_t shm_lpid; /* pid of last operator */
unsigned short shm_nattch; /* no. of current attaches */
unsigned short shm_unused; /* compatibility */
void *shm_unused2; /* ditto - used by DIPC */
void *shm_unused3; /* unused */
};
/* Include the definition of shmid64_ds and shminfo64 */
#include <asm/shmbuf.h>
/* permission flag for shmget */
#define SHM_R 0400 /* or S_IRUGO from <linux/stat.h> */
#define SHM_W 0200 /* or S_IWUGO from <linux/stat.h> */
/* mode for attach */
#define SHM_RDONLY 010000 /* read-only access */
#define SHM_RND 020000 /* round attach address to SHMLBA boundary */
#define SHM_REMAP 040000 /* take-over region on attach */
#define SHM_EXEC 0100000 /* execution access */
/* super user shmctl commands */
#define SHM_LOCK 11
#define SHM_UNLOCK 12
/* ipcs ctl commands */
#define SHM_STAT 13
#define SHM_INFO 14
/* Obsolete, used only for backwards compatibility */
struct shminfo {
int shmmax;
int shmmin;
int shmmni;
int shmseg;
int shmall;
};
struct shm_info {
int used_ids;
__kernel_ulong_t shm_tot; /* total allocated shm */
__kernel_ulong_t shm_rss; /* total resident shm */
__kernel_ulong_t shm_swp; /* total swapped shm */
__kernel_ulong_t swap_attempts;
__kernel_ulong_t swap_successes;
};
#endif /* _LINUX_SHM_H_ */
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