cfitsio (4.3.1)
1 /* S H A R E D M E M O R Y D R I V E R
2 =======================================
3
4 by Jerzy.Borkowski@obs.unige.ch
5
6 09-Mar-98 : initial version 1.0 released
7 23-Mar-98 : shared_malloc now accepts new handle as an argument
8 */
9
10
11 #include <sys/ipc.h> /* this is necessary for Solaris/Linux */
12 #include <sys/shm.h>
13 #include <sys/sem.h>
14
15 #ifdef _AIX
16 #include <fcntl.h>
17 #else
18 #include <sys/fcntl.h>
19 #endif
20
21 /* configuration parameters */
22
23 #define SHARED_MAXSEG (16) /* maximum number of shared memory blocks */
24
25 #define SHARED_KEYBASE (14011963) /* base for shared memory keys, may be overriden by getenv */
26 #define SHARED_FDNAME ("/tmp/.shmem-lockfile") /* template for lock file name */
27
28 #define SHARED_ENV_KEYBASE ("SHMEM_LIB_KEYBASE") /* name of environment variable */
29 #define SHARED_ENV_MAXSEG ("SHMEM_LIB_MAXSEG") /* name of environment variable */
30
31 /* useful constants */
32
33 #define SHARED_RDONLY (0) /* flag for shared_(un)lock, lock for read */
34 #define SHARED_RDWRITE (1) /* flag for shared_(un)lock, lock for write */
35 #define SHARED_WAIT (0) /* flag for shared_lock, block if cannot lock immediate */
36 #define SHARED_NOWAIT (2) /* flag for shared_lock, fail if cannot lock immediate */
37 #define SHARED_NOLOCK (0x100) /* flag for shared_validate function */
38
39 #define SHARED_RESIZE (4) /* flag for shared_malloc, object is resizeable */
40 #define SHARED_PERSIST (8) /* flag for shared_malloc, object is not deleted after last proc detaches */
41
42 #define SHARED_INVALID (-1) /* invalid handle for semaphore/shared memory */
43
44 #define SHARED_EMPTY (0) /* entries for shared_used table */
45 #define SHARED_USED (1)
46
47 #define SHARED_GRANUL (16384) /* granularity of shared_malloc allocation = phys page size, system dependent */
48
49
50
51 /* checkpoints in shared memory segments - might be omitted */
52
53 #define SHARED_ID_0 ('J') /* first byte of identifier in BLKHEAD */
54 #define SHARED_ID_1 ('B') /* second byte of identifier in BLKHEAD */
55
56 #define BLOCK_REG (0) /* value for tflag member of BLKHEAD */
57 #define BLOCK_SHARED (1) /* value for tflag member of BLKHEAD */
58
59 /* generic error codes */
60
61 #define SHARED_OK (0)
62
63 #define SHARED_ERR_MIN_IDX SHARED_BADARG
64 #define SHARED_ERR_MAX_IDX SHARED_NORESIZE
65
66
67 #define DAL_SHM_FREE (0)
68 #define DAL_SHM_USED (1)
69
70 #define DAL_SHM_ID0 ('D')
71 #define DAL_SHM_ID1 ('S')
72 #define DAL_SHM_ID2 ('M')
73
74 #define DAL_SHM_SEGHEAD_ID (0x19630114)
75
76
77
78 /* data types */
79
80 /* BLKHEAD object is placed at the beginning of every memory segment (both
81 shared and regular) to allow automatic recognition of segments type */
82
83 typedef union
84 { struct BLKHEADstruct
85 { char ID[2]; /* ID = 'JB', just as a checkpoint */
86 char tflag; /* is it shared memory or regular one ? */
87 int handle; /* this is not necessary, used only for non-resizeable objects via ptr */
88 } s;
89 double d; /* for proper alignment on every machine */
90 } BLKHEAD;
91
92 typedef void *SHARED_P; /* generic type of shared memory pointer */
93
94 typedef struct SHARED_GTABstruct /* data type used in global table */
95 { int sem; /* access semaphore (1 field): process count */
96 int semkey; /* key value used to generate semaphore handle */
97 int key; /* key value used to generate shared memory handle (realloc changes it) */
98 int handle; /* handle of shared memory segment */
99 int size; /* size of shared memory segment */
100 int nprocdebug; /* attached proc counter, helps remove zombie segments */
101 char attr; /* attributes of shared memory object */
102 } SHARED_GTAB;
103
104 typedef struct SHARED_LTABstruct /* data type used in local table */
105 { BLKHEAD *p; /* pointer to segment (may be null) */
106 int tcnt; /* number of threads in this process attached to segment */
107 int lkcnt; /* >=0 <- number of read locks, -1 - write lock */
108 long seekpos; /* current pointer position, read/write/seek operations change it */
109 } SHARED_LTAB;
110
111
112 /* system dependent definitions */
113
114 #ifndef HAVE_FLOCK_T
115 typedef struct flock flock_t;
116 #define HAVE_FLOCK_T
117 #endif
118
119 #ifndef HAVE_UNION_SEMUN
120 union semun
121 { int val;
122 struct semid_ds *buf;
123 unsigned short *array;
124 };
125 #define HAVE_UNION_SEMUN
126 #endif
127
128
129 typedef struct DAL_SHM_SEGHEAD_STRUCT DAL_SHM_SEGHEAD;
130
131 struct DAL_SHM_SEGHEAD_STRUCT
132 { int ID; /* ID for debugging */
133 int h; /* handle of sh. mem */
134 int size; /* size of data area */
135 int nodeidx; /* offset of root object (node struct typically) */
136 };
137
138 /* API routines */
139
140 #ifdef __cplusplus
141 extern "C" {
142 #endif
143
144 void shared_cleanup(void); /* must be called at exit/abort */
145 int shared_init(int debug_msgs); /* must be called before any other shared memory routine */
146 int shared_recover(int id); /* try to recover dormant segment(s) after applic crash */
147 int shared_malloc(long size, int mode, int newhandle); /* allocate n-bytes of shared memory */
148 int shared_attach(int idx); /* attach to segment given index to table */
149 int shared_free(int idx); /* release shared memory */
150 SHARED_P shared_lock(int idx, int mode); /* lock segment for reading */
151 SHARED_P shared_realloc(int idx, long newsize); /* reallocate n-bytes of shared memory (ON LOCKED SEGMENT ONLY) */
152 int shared_size(int idx); /* get size of attached shared memory segment (ON LOCKED SEGMENT ONLY) */
153 int shared_attr(int idx); /* get attributes of attached shared memory segment (ON LOCKED SEGMENT ONLY) */
154 int shared_set_attr(int idx, int newattr); /* set attributes of attached shared memory segment (ON LOCKED SEGMENT ONLY) */
155 int shared_unlock(int idx); /* unlock segment (ON LOCKED SEGMENT ONLY) */
156 int shared_set_debug(int debug_msgs); /* set/reset debug mode */
157 int shared_set_createmode(int mode); /* set/reset debug mode */
158 int shared_list(int id); /* list segment(s) */
159 int shared_uncond_delete(int id); /* uncondintionally delete (NOWAIT operation) segment(s) */
160 int shared_getaddr(int id, char **address); /* get starting address of FITS file in segment */
161
162 int smem_init(void);
163 int smem_shutdown(void);
164 int smem_setoptions(int options);
165 int smem_getoptions(int *options);
166 int smem_getversion(int *version);
167 int smem_open(char *filename, int rwmode, int *driverhandle);
168 int smem_create(char *filename, int *driverhandle);
169 int smem_close(int driverhandle);
170 int smem_remove(char *filename);
171 int smem_size(int driverhandle, LONGLONG *size);
172 int smem_flush(int driverhandle);
173 int smem_seek(int driverhandle, LONGLONG offset);
174 int smem_read(int driverhandle, void *buffer, long nbytes);
175 int smem_write(int driverhandle, void *buffer, long nbytes);
176
177 #ifdef __cplusplus
178 }
179 #endif
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