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