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 SHM_NAME_MAX
  32 #define SHM_NAME_MAX NAME_MAX
  33 #endif
  34     typedef char        shm_name_t[SHM_NAME_MAX];
  35     typedef shm_name_t jack_shm_id_t;
  36
  37 #elif WIN32   // steph TO CHECK
  38 #define NAME_MAX            255
  39 #ifndef SHM_NAME_MAX
  40 #define SHM_NAME_MAX NAME_MAX
  41 #endif
  42     typedef char        shm_name_t[SHM_NAME_MAX];
  43     typedef shm_name_t jack_shm_id_t;
  44
  45 #else
  46     /* System V SHM */
  47     typedef int jack_shm_id_t;
  48 #endif /* SHM type */
  49
  50     /* shared memory type */
  51     typedef enum {
  52         shm_POSIX = 1,                  /* POSIX shared memory */
  53         shm_SYSV = 2,                   /* System V shared memory */
  54         shm_WIN32 = 3                   /* Windows 32 shared memory */
  55     } jack_shmtype_t;
  56
  57     typedef int16_t jack_shm_registry_index_t;
  58
  59     /**
  60      * A structure holding information about shared memory allocated by
  61      * JACK. this persists across invocations of JACK, and can be used by
  62      * multiple JACK servers.  It contains no pointers and is valid across
  63      * address spaces.
  64      *
  65      * The registry consists of two parts: a header including an array of
  66      * server names, followed by an array of segment registry entries.
  67      */
  68     typedef struct _jack_shm_server {
  69 #ifdef WIN32
  70         int     pid;    /* process ID */
  71 #else
  72
  73         pid_t pid;      /* process ID */
  74 #endif
  75
  76         char    name[JACK_SERVER_NAME_SIZE];
  77     }
  78     jack_shm_server_t;
  79
  80     typedef struct _jack_shm_header {
  81         uint32_t        magic;  /* magic number */
  82         uint16_t        protocol;       /* JACK protocol version */
  83         jack_shmtype_t  type;   /* shm type */
  84         jack_shmsize_t  size;   /* total registry segment size */
  85         jack_shmsize_t  hdr_len;        /* size of header */
  86         jack_shmsize_t  entry_len; /* size of registry entry */
  87         jack_shm_server_t server[MAX_SERVERS]; /* current server array */
  88     }
  89     jack_shm_header_t;
  90
  91     typedef struct _jack_shm_registry {
  92         jack_shm_registry_index_t index;     /* offset into the registry */
  93
  94 #ifdef WIN32
  95
  96         int     allocator; /* PID that created shm segment */
  97 #else
  98
  99         pid_t allocator; /* PID that created shm segment */
 100 #endif
 101
 102         jack_shmsize_t size;      /* for POSIX unattach */
 103         jack_shm_id_t id;        /* API specific, see above */
 104     }
 105     jack_shm_registry_t;
 106
 107 #define JACK_SHM_REGISTRY_SIZE (sizeof (jack_shm_header_t) \
 108                                 + sizeof (jack_shm_registry_t) * MAX_SHM_ID)
 109
 110     /**
 111      * a structure holding information about shared memory
 112      * allocated by JACK. this version is valid only
 113      * for a given address space. It contains a pointer
 114      * indicating where the shared memory has been
 115      * attached to the address space.
 116      */
 117     typedef struct _jack_shm_info {
 118         jack_shm_registry_index_t index;       /* offset into the registry */
 119         size_t size;
 120         void *attached_at; /* address where attached */
 121     }
 122     jack_shm_info_t;
 123
 124     /* utility functions used only within JACK */
 125
 126     void jack_shm_copy_from_registry (jack_shm_info_t*,
 127                 jack_shm_registry_index_t);
 128     void jack_shm_copy_to_registry (jack_shm_info_t*,
 129                                                jack_shm_registry_index_t*);
 130     void jack_release_shm_info (jack_shm_registry_index_t);
 131     char* jack_shm_addr (jack_shm_info_t* si);  // steph
 132
 133     // here begin the API
 134     int jack_register_server (const char *server_name, int new_registry);
 135     void jack_unregister_server (const char *server_name);
 136
 137     int jack_initialize_shm (const char *server_name);
 138     int jack_initialize_shm_server (void);  // steph
 139     int jack_initialize_shm_client (void);  // steph
 140     int jack_cleanup_shm (void);
 141
 142     int jack_shmalloc (const char *shm_name, jack_shmsize_t size,
 143                                   jack_shm_info_t* result);
 144     void jack_release_shm (jack_shm_info_t*);
 145     void jack_destroy_shm (jack_shm_info_t*);
 146     int jack_attach_shm (jack_shm_info_t*);
 147     int jack_attach_shm_read (jack_shm_info_t*); // steph
 148     int jack_resize_shm (jack_shm_info_t*, jack_shmsize_t size);
 149
 150 #ifdef __cplusplus
 151 }
 152 #endif
 153
 154 #endif /* __jack_shm_h__ */