common/shm.h

   1 #ifndef __jack_shm_h__
   2 #define __jack_shm_h__
   3
   4 #include <limits.h>
   5 #include <sys/types.h>
   6 #include "types.h"
   7 #include "JackCompilerDeps.h"
   8
   9 #define TRUE 1
  10 #define FALSE 0
  11
  12 #ifdef __cplusplus
  13 extern "C"
  14 {
  15 #endif
  16
  17 #define MAX_SERVERS 8                   /* maximum concurrent servers */
  18 #define MAX_SHM_ID 256                  /* generally about 16 per server */
  19 #define JACK_SERVER_NAME_SIZE 256       /* maximum length of server name */
  20 #define JACK_SHM_MAGIC 0x4a41434b       /* shm magic number: "JACK" */
  21 #define JACK_SHM_NULL_INDEX -1          /* NULL SHM index */
  22 #define JACK_SHM_REGISTRY_INDEX -2      /* pseudo SHM index for registry */
  23
  24
  25     /* On Mac OS X, SHM_NAME_MAX is the maximum length of a shared memory
  26      * segment name (instead of NAME_MAX or PATH_MAX as defined by the
  27      * standard).
  28      */
  29 #ifdef USE_POSIX_SHM
  30
  31 #ifndef NAME_MAX
  32 #define NAME_MAX            255
  33 #endif
  34
  35 #ifndef SHM_NAME_MAX
  36 #define SHM_NAME_MAX NAME_MAX
  37 #endif
  38     typedef char shm_name_t[SHM_NAME_MAX];
  39     typedef shm_name_t jack_shm_id_t;
  40
  41 #elif WIN32   // TO CHECK
  42 #define NAME_MAX            255
  43 #ifndef SHM_NAME_MAX
  44 #define SHM_NAME_MAX NAME_MAX
  45 #endif
  46     typedef char shm_name_t[SHM_NAME_MAX];
  47     typedef shm_name_t jack_shm_id_t;
  48
  49 #else
  50     /* System V SHM */
  51     typedef int jack_shm_id_t;
  52 #endif /* SHM type */
  53
  54     /* shared memory type */
  55     typedef enum {
  56         shm_POSIX = 1,                  /* POSIX shared memory */
  57         shm_SYSV = 2,                   /* System V shared memory */
  58         shm_WIN32 = 3                   /* Windows 32 shared memory */
  59     } jack_shmtype_t;
  60
  61     typedef int16_t jack_shm_registry_index_t;
  62
  63     /**
  64      * A structure holding information about shared memory allocated by
  65      * JACK. this persists across invocations of JACK, and can be used by
  66      * multiple JACK servers.  It contains no pointers and is valid across
  67      * address spaces.
  68      *
  69      * The registry consists of two parts: a header including an array of
  70      * server names, followed by an array of segment registry entries.
  71      */
  72     typedef struct _jack_shm_server {
  73 #ifdef WIN32
  74         int     pid;    /* process ID */
  75 #else
  76         pid_t pid;      /* process ID */
  77 #endif
  78
  79         char    name[JACK_SERVER_NAME_SIZE];
  80     }
  81     jack_shm_server_t;
  82
  83     typedef struct _jack_shm_header {
  84         uint32_t        magic;  /* magic number */
  85         uint16_t        protocol;       /* JACK protocol version */
  86         jack_shmtype_t  type;   /* shm type */
  87         jack_shmsize_t  size;   /* total registry segment size */
  88         jack_shmsize_t  hdr_len;        /* size of header */
  89         jack_shmsize_t  entry_len; /* size of registry entry */
  90         jack_shm_server_t server[MAX_SERVERS]; /* current server array */
  91     }
  92     jack_shm_header_t;
  93
  94     typedef struct _jack_shm_registry {
  95         jack_shm_registry_index_t index;     /* offset into the registry */
  96
  97 #ifdef WIN32
  98         int     allocator; /* PID that created shm segment */
  99 #else
 100         pid_t allocator; /* PID that created shm segment */
 101 #endif
 102
 103         jack_shmsize_t size;      /* for POSIX unattach */
 104         jack_shm_id_t id;        /* API specific, see above */
 105     }
 106     jack_shm_registry_t;
 107
 108 #define JACK_SHM_REGISTRY_SIZE (sizeof (jack_shm_header_t) \
 109                                 + sizeof (jack_shm_registry_t) * MAX_SHM_ID)
 110
 111     /**
 112      * a structure holding information about shared memory
 113      * allocated by JACK. this version is valid only
 114      * for a given address space. It contains a pointer
 115      * indicating where the shared memory has been
 116      * attached to the address space.
 117      */
 118
 119     typedef struct _jack_shm_info {
 120         jack_shm_registry_index_t index;       /* offset into the registry */
 121         uint32_t size;
 122         union {
 123             void *attached_at;  /* address where attached */
 124             char ptr_size[8];
 125         } ptr;  /* a "pointer" that has the same 8 bytes size when compling in 32 or 64 bits */
 126     }
 127     POST_PACKED_STRUCTURE jack_shm_info_t;
 128
 129     /* utility functions used only within JACK */
 130
 131     void jack_shm_copy_from_registry (jack_shm_info_t*,
 132                 jack_shm_registry_index_t);
 133     void jack_shm_copy_to_registry (jack_shm_info_t*,
 134                                                jack_shm_registry_index_t*);
 135     void jack_release_shm_info (jack_shm_registry_index_t);
 136     char* jack_shm_addr (jack_shm_info_t* si);
 137
 138     // here begin the API
 139     int jack_register_server (const char *server_name, int new_registry);
 140     void jack_unregister_server (const char *server_name);
 141
 142     int jack_initialize_shm (const char *server_name);
 143     int jack_initialize_shm_server (void);
 144     int jack_initialize_shm_client (void);
 145     int jack_cleanup_shm (void);
 146
 147     int jack_shmalloc (const char *shm_name, jack_shmsize_t size,
 148                                   jack_shm_info_t* result);
 149     void jack_release_shm (jack_shm_info_t*);
 150     void jack_destroy_shm (jack_shm_info_t*);
 151     int jack_attach_shm (jack_shm_info_t*);
 152     int jack_attach_shm_read (jack_shm_info_t*);
 153     int jack_resize_shm (jack_shm_info_t*, jack_shmsize_t size);
 154
 155 #ifdef __cplusplus
 156 }
 157 #endif
 158
 159 #endif /* __jack_shm_h__ */