Initial commit

1 files changed, 953 insertions, 0 deletions

diff --git a/pkg/tbtables/cfitsio/drvrsmem.c b/pkg/tbtables/cfitsio/drvrsmem.c
new file mode 100644
index 00000000..3c2b4032
--- /dev/null
+++ b/pkg/tbtables/cfitsio/drvrsmem.c
@@ -0,0 +1,953 @@
+/*              S H A R E D   M E M O R Y   D R I V E R
+                =======================================
+
+                  by Jerzy.Borkowski@obs.unige.ch
+
+09-Mar-98 : initial version 1.0 released
+23-Mar-98 : shared_malloc now accepts new handle as an argument
+23-Mar-98 : shmem://0, shmem://1, etc changed to shmem://h0, etc due to bug
+            in url parser.
+10-Apr-98 : code cleanup
+13-May-99 : delayed initialization added, global table deleted on exit when
+            no shmem segments remain, and last process terminates
+*/
+
+#ifdef HAVE_SHMEM_SERVICES
+#include "fitsio2.h"                         /* drvrsmem.h is included by it */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <unistd.h>
+
+
+static int shared_kbase = 0;                    /* base for shared memory handles */
+static int shared_maxseg = 0;                   /* max number of shared memory blocks */
+static int shared_range = 0;                    /* max number of tried entries */
+static int shared_fd = SHARED_INVALID;          /* handle of global access lock file */
+static int shared_gt_h = SHARED_INVALID;        /* handle of global table segment */
+static SHARED_LTAB *shared_lt = NULL;           /* local table pointer */
+static SHARED_GTAB *shared_gt = NULL;           /* global table pointer */
+static int shared_create_mode = 0666;           /* permission flags for created objects */
+static int shared_debug = 1;                    /* simple debugging tool, set to 0 to disable messages */
+static int shared_init_called = 0;              /* flag whether shared_init() has been called, used for delayed init */
+
+                /* static support routines prototypes */
+
+static  int shared_clear_entry(int idx);        /* unconditionally clear entry */
+static  int shared_destroy_entry(int idx);      /* unconditionally destroy sema & shseg and clear entry */
+static  int shared_mux(int idx, int mode);      /* obtain exclusive access to specified segment */
+static  int shared_demux(int idx, int mode);    /* free exclusive access to specified segment */
+
+static  int shared_process_count(int sem);      /* valid only for time of invocation */
+static  int shared_delta_process(int sem, int delta); /* change number of processes hanging on segment */
+static  int shared_attach_process(int sem);
+static  int shared_detach_process(int sem);
+static  int shared_get_free_entry(int newhandle);       /* get free entry in shared_key, or -1, entry is set rw locked */
+static  int shared_get_hash(long size, int idx);/* return hash value for malloc */
+static  long shared_adjust_size(long size);     /* size must be >= 0 !!! */
+static  int shared_check_locked_index(int idx); /* verify that given idx is valid */ 
+static  int shared_map(int idx);                /* map all tables for given idx, check for validity */
+static  int shared_validate(int idx, int mode); /* use intrnally inside crit.sect !!! */
+
+                /* support routines - initialization */
+
+
+static  int shared_clear_entry(int idx)         /* unconditionally clear entry */
+ { if ((idx < 0) || (idx >= shared_maxseg)) return(SHARED_BADARG);
+   shared_gt[idx].key = SHARED_INVALID;         /* clear entries in global table */
+   shared_gt[idx].handle = SHARED_INVALID;
+   shared_gt[idx].sem = SHARED_INVALID;
+   shared_gt[idx].semkey = SHARED_INVALID;
+   shared_gt[idx].nprocdebug = 0;
+   shared_gt[idx].size = 0;
+   shared_gt[idx].attr = 0;
+
+   return(SHARED_OK);
+ }
+
+static  int shared_destroy_entry(int idx)       /* unconditionally destroy sema & shseg and clear entry */
+ { int r, r2;
+   union semun filler;
+
+   if ((idx < 0) || (idx >= shared_maxseg)) return(SHARED_BADARG);
+   r2 = r = SHARED_OK;
+   filler.val = 0;                              /* this is to make cc happy (warning otherwise) */
+   if (SHARED_INVALID != shared_gt[idx].sem)  r = semctl(shared_gt[idx].sem, 0, IPC_RMID, filler); /* destroy semaphore */
+   if (SHARED_INVALID != shared_gt[idx].handle) r2 = shmctl(shared_gt[idx].handle, IPC_RMID, 0); /* destroy shared memory segment */
+   if (SHARED_OK == r) r = r2;                  /* accumulate error code in r, free r2 */
+   r2 = shared_clear_entry(idx);
+   return((SHARED_OK == r) ? r2 : r);
+ }
+
+void    shared_cleanup(void)                    /* this must (should) be called during exit/abort */
+ { int          i, j, r, oktodelete, filelocked, segmentspresent;
+   flock_t      flk;
+   struct shmid_ds  ds;
+
+   if (shared_debug) printf("shared_cleanup:");
+   if (NULL != shared_lt)
+     { if (shared_debug) printf(" deleting segments:");
+       for (i=0; i<shared_maxseg; i++)
+        { if (0 == shared_lt[i].tcnt) continue; /* we're not using this segment, skip this ... */
+          if (-1 != shared_lt[i].lkcnt) continue;  /* seg not R/W locked by us, skip this ... */
+
+          r = shared_destroy_entry(i);          /* destroy unconditionally sema & segment */
+          if (shared_debug) 
+            { if (SHARED_OK == r) printf(" [%d]", i);
+              else printf(" [error on %d !!!!]", i);
+
+            }
+        }
+       free((void *)shared_lt);                 /* free local table */
+       shared_lt = NULL;
+     }
+   if (NULL != shared_gt)                       /* detach global index table */
+     { oktodelete = 0;
+       filelocked = 0;
+       if (shared_debug) printf(" detaching globalsharedtable");
+       if (SHARED_INVALID != shared_fd)
+
+       flk.l_type = F_WRLCK;                    /* lock whole lock file */
+       flk.l_whence = 0;
+       flk.l_start = 0;
+       flk.l_len = shared_maxseg;
+       if (-1 != fcntl(shared_fd, F_SETLK, &flk))
+         { filelocked = 1;                      /* success, scan global table, to see if there are any segs */
+           segmentspresent = 0;                 /* assume, there are no segs in the system */
+           for (j=0; j<shared_maxseg; j++)
+            { if (SHARED_INVALID != shared_gt[j].key)
+                { segmentspresent = 1;          /* yes, there is at least one */
+                  break;
+                }
+            }
+           if (0 == segmentspresent)            /* if there are no segs ... */
+             if (0 == shmctl(shared_gt_h, IPC_STAT, &ds)) /* get number of processes attached to table */
+               { if (ds.shm_nattch <= 1) oktodelete = 1; /* if only one (we), then it is safe (but see text 4 lines later) to unlink */
+               }
+         }
+       shmdt((char *)shared_gt);                /* detach global table */
+       if (oktodelete)                          /* delete global table from system, if no shm seg present */
+         { shmctl(shared_gt_h, IPC_RMID, 0);    /* there is a race condition here - time window between shmdt and shmctl */
+           shared_gt_h = SHARED_INVALID;
+         }
+       shared_gt = NULL;
+       if (filelocked)                          /* if we locked, we need to unlock */
+         { flk.l_type = F_UNLCK;
+           flk.l_whence = 0;
+           flk.l_start = 0;
+           flk.l_len = shared_maxseg;
+           fcntl(shared_fd, F_SETLK, &flk);
+         }
+     }
+   shared_gt_h = SHARED_INVALID;
+
+   if (SHARED_INVALID != shared_fd)             /* close lock file */
+     { if (shared_debug) printf(" closing lockfile");
+       close(shared_fd);
+       shared_fd = SHARED_INVALID;
+     }
+
+   
+   shared_kbase = 0;
+   shared_maxseg = 0;
+   shared_range = 0;
+   shared_init_called = 0;
+
+   if (shared_debug) printf(" <<done>>\n");
+   return;
+ }
+
+
+int     shared_init(int debug_msgs)             /* initialize shared memory stuff, you have to call this routine once */
+ { int i;
+   char buf[1000], *p;
+   mode_t oldumask;
+
+   shared_init_called = 1;                      /* tell everybody no need to call us for the 2nd time */
+   shared_debug = debug_msgs;                   /* set required debug mode */
+   
+   if (shared_debug) printf("shared_init:");
+
+   shared_kbase = 0;                            /* adapt to current env. settings */
+   if (NULL != (p = getenv(SHARED_ENV_KEYBASE))) shared_kbase = atoi(p);
+   if (0 == shared_kbase) shared_kbase = SHARED_KEYBASE;
+   if (shared_debug) printf(" keybase=%d", shared_kbase);
+
+   shared_maxseg = 0;
+   if (NULL != (p = getenv(SHARED_ENV_MAXSEG))) shared_maxseg = atoi(p);
+   if (0 == shared_maxseg) shared_maxseg = SHARED_MAXSEG;
+   if (shared_debug) printf(" maxseg=%d", shared_maxseg);
+   
+   shared_range = 3 * shared_maxseg;
+
+   if (SHARED_INVALID == shared_fd)             /* create rw locking file (this file is never deleted) */
+     { if (shared_debug) printf(" lockfileinit=");
+       sprintf(buf, "%s.%d.%d", SHARED_FDNAME, shared_kbase, shared_maxseg);
+       oldumask = umask(0);
+
+       shared_fd = open(buf, O_TRUNC | O_EXCL | O_CREAT | O_RDWR, shared_create_mode);
+       umask(oldumask);
+       if (SHARED_INVALID == shared_fd)         /* or just open rw locking file, in case it already exists */
+         { shared_fd = open(buf, O_TRUNC | O_RDWR, shared_create_mode);
+           if (SHARED_INVALID == shared_fd) return(SHARED_NOFILE);
+           if (shared_debug) printf("slave");
+
+         }
+       else
+         { if (shared_debug) printf("master");
+         }
+     }
+
+   if (SHARED_INVALID == shared_gt_h)           /* global table not attached, try to create it in shared memory */
+     { if (shared_debug) printf(" globalsharedtableinit=");
+       shared_gt_h = shmget(shared_kbase, shared_maxseg * sizeof(SHARED_GTAB), IPC_CREAT | IPC_EXCL | shared_create_mode); /* try open as a master */
+       if (SHARED_INVALID == shared_gt_h)       /* if failed, try to open as a slave */
+         { shared_gt_h = shmget(shared_kbase, shared_maxseg * sizeof(SHARED_GTAB), shared_create_mode);
+           if (SHARED_INVALID == shared_gt_h) return(SHARED_IPCERR); /* means deleted ID residing in system, shared mem unusable ... */
+           shared_gt = (SHARED_GTAB *)shmat(shared_gt_h, 0, 0); /* attach segment */
+           if (((SHARED_GTAB *)SHARED_INVALID) == shared_gt) return(SHARED_IPCERR);
+           if (shared_debug) printf("slave");
+         }
+       else
+         { shared_gt = (SHARED_GTAB *)shmat(shared_gt_h, 0, 0); /* attach segment */
+           if (((SHARED_GTAB *)SHARED_INVALID) == shared_gt) return(SHARED_IPCERR);
+           for (i=0; i<shared_maxseg; i++) shared_clear_entry(i);       /* since we are master, init data */
+           if (shared_debug) printf("master");
+         }
+     }
+
+   if (NULL == shared_lt)                       /* initialize local table */
+     { if (shared_debug) printf(" localtableinit=");
+       if (NULL == (shared_lt = (SHARED_LTAB *)malloc(shared_maxseg * sizeof(SHARED_LTAB)))) return(SHARED_NOMEM);
+       for (i=0; i<shared_maxseg; i++)
+        { shared_lt[i].p = NULL;                /* not mapped */
+          shared_lt[i].tcnt = 0;                /* unused (or zero threads using this seg) */
+          shared_lt[i].lkcnt = 0;               /* segment is unlocked */
+          shared_lt[i].seekpos = 0L;            /* r/w pointer at the beginning of file */
+        }
+       if (shared_debug) printf("ok");
+     }
+
+   atexit(shared_cleanup);                      /* we want shared_cleanup to be called at exit or abort */
+
+   if (shared_debug) printf(" <<done>>\n");
+   return(SHARED_OK);
+ }
+
+
+int     shared_recover(int id)                  /* try to recover dormant segments after applic crash */
+ { int i, r, r2;
+
+   if (NULL == shared_gt) return(SHARED_NOTINIT);       /* not initialized */
+   if (NULL == shared_lt) return(SHARED_NOTINIT);       /* not initialized */
+   r = SHARED_OK;
+   for (i=0; i<shared_maxseg; i++)
+    { if (-1 != id) if (i != id) continue;
+      if (shared_lt[i].tcnt) continue;          /* somebody (we) is using it */
+      if (SHARED_INVALID == shared_gt[i].key) continue; /* unused slot */
+      if (shared_mux(i, SHARED_NOWAIT | SHARED_RDWRITE)) continue; /* acquire exclusive access to segment, but do not wait */
+      r2 = shared_process_count(shared_gt[i].sem);
+      if ((shared_gt[i].nprocdebug > r2) || (0 == r2))
+        { if (shared_debug) printf("Bogus handle=%d nproc=%d sema=%d:", i, shared_gt[i].nprocdebug, r2);
+          r = shared_destroy_entry(i);
+          if (shared_debug)
+            { printf("%s", r ? "error couldn't clear handle" : "handle cleared");
+            }
+        }
+      shared_demux(i, SHARED_RDWRITE);
+    }
+   return(r);                                           /* table full */
+ }
+
+                /* API routines - mutexes and locking */
+
+static  int shared_mux(int idx, int mode)       /* obtain exclusive access to specified segment */
+ { flock_t flk;
+
+   int r;
+
+   if (0 == shared_init_called)                 /* delayed initialization */
+     { if (SHARED_OK != (r = shared_init(0))) return(r);
+
+     }
+   if (SHARED_INVALID == shared_fd) return(SHARED_NOTINIT);
+   if ((idx < 0) || (idx >= shared_maxseg)) return(SHARED_BADARG);
+   flk.l_type = ((mode & SHARED_RDWRITE) ? F_WRLCK : F_RDLCK);
+   flk.l_whence = 0;
+   flk.l_start = idx;
+   flk.l_len = 1;
+   if (shared_debug) printf(" [mux (%d): ", idx);
+   if (-1 == fcntl(shared_fd, ((mode & SHARED_NOWAIT) ? F_SETLK : F_SETLKW), &flk))
+     { switch (errno)
+        { case EAGAIN: ;
+
+          case EACCES: if (shared_debug) printf("again]");
+                       return(SHARED_AGAIN);
+          default:     if (shared_debug) printf("err]");
+                       return(SHARED_IPCERR);
+        }
+     }
+   if (shared_debug) printf("ok]");
+   return(SHARED_OK);
+ }
+
+
+
+static  int shared_demux(int idx, int mode)     /* free exclusive access to specified segment */
+ { flock_t flk;
+
+   if (SHARED_INVALID == shared_fd) return(SHARED_NOTINIT);
+   if ((idx < 0) || (idx >= shared_maxseg)) return(SHARED_BADARG);
+   flk.l_type = F_UNLCK;
+   flk.l_whence = 0;
+   flk.l_start = idx;
+   flk.l_len = 1;
+   if (shared_debug) printf(" [demux (%d): ", idx);
+   if (-1 == fcntl(shared_fd, F_SETLKW, &flk))
+     { switch (errno)
+        { case EAGAIN: ;
+          case EACCES: if (shared_debug) printf("again]");
+                       return(SHARED_AGAIN);
+          default:     if (shared_debug) printf("err]");
+                       return(SHARED_IPCERR);
+        }
+
+     }
+   if (shared_debug) printf("mode=%d ok]", mode);
+   return(SHARED_OK);
+ }
+
+
+
+static int shared_process_count(int sem)                /* valid only for time of invocation */
+ { union semun su;
+
+   su.val = 0;                                          /* to force compiler not to give warning messages */
+   return(semctl(sem, 0, GETVAL, su));                  /* su is unused here */
+ }
+
+
+static int shared_delta_process(int sem, int delta)     /* change number of processes hanging on segment */
+ { struct sembuf sb;
+ 
+   if (SHARED_INVALID == sem) return(SHARED_BADARG);    /* semaphore not attached */
+   sb.sem_num = 0;
+   sb.sem_op = delta;
+   sb.sem_flg = SEM_UNDO;
+   return((-1 == semop(sem, &sb, 1)) ? SHARED_IPCERR : SHARED_OK);
+ }
+
+
+static int shared_attach_process(int sem)
+ { if (shared_debug) printf(" [attach process]");
+   return(shared_delta_process(sem, 1));
+ }
+
+
+static int shared_detach_process(int sem)
+ { if (shared_debug) printf(" [detach process]");
+   return(shared_delta_process(sem, -1));
+ }
+
+                /* API routines - hashing and searching */
+
+
+static int shared_get_free_entry(int newhandle)         /* get newhandle, or -1, entry is set rw locked */
+ {
+   if (NULL == shared_gt) return(-1);                   /* not initialized */
+   if (NULL == shared_lt) return(-1);                   /* not initialized */
+   if (newhandle < 0) return(-1);
+   if (newhandle >= shared_maxseg) return(-1);
+   if (shared_lt[newhandle].tcnt) return(-1);                   /* somebody (we) is using it */
+   if (shared_mux(newhandle, SHARED_NOWAIT | SHARED_RDWRITE)) return(-1); /* used by others */
+   if (SHARED_INVALID == shared_gt[newhandle].key) return(newhandle); /* we have found free slot, lock it and return index */
+   shared_demux(newhandle, SHARED_RDWRITE);
+   if (shared_debug) printf("[free_entry - ERROR - entry unusable]");
+   return(-1);                                          /* table full */
+ }
+
+
+static int shared_get_hash(long size, int idx)  /* return hash value for malloc */
+ { static int counter = 0;
+   int hash;
+
+   hash = (counter + size * idx) % shared_range;
+   counter = (counter + 1) % shared_range;
+   return(hash);
+ }
+
+
+static  long shared_adjust_size(long size)              /* size must be >= 0 !!! */
+ { return(((size + sizeof(BLKHEAD) + SHARED_GRANUL - 1) / SHARED_GRANUL) * SHARED_GRANUL); }
+
+
+                /* API routines - core : malloc/realloc/free/attach/detach/lock/unlock */
+
+int     shared_malloc(long size, int mode, int newhandle)               /* return idx or SHARED_INVALID */
+ { int h, i, r, idx, key;
+   union semun filler;
+   BLKHEAD *bp;
+   
+   if (0 == shared_init_called)                 /* delayed initialization */
+     { if (SHARED_OK != (r = shared_init(0))) return(r);
+     }
+   if (shared_debug) printf("malloc (size = %ld, mode = %d):", size, mode);
+   if (size < 0) return(SHARED_INVALID);
+   if (-1 == (idx = shared_get_free_entry(newhandle)))  return(SHARED_INVALID);
+   if (shared_debug) printf(" idx=%d", idx);
+   for (i = 0; ; i++)
+    { if (i >= shared_range)                            /* table full, signal error & exit */
+        { shared_demux(idx, SHARED_RDWRITE);
+          return(SHARED_INVALID);
+        }
+      key = shared_kbase + ((i + shared_get_hash(size, idx)) % shared_range);
+      if (shared_debug) printf(" key=%d", key);
+      h = shmget(key, shared_adjust_size(size), IPC_CREAT | IPC_EXCL | shared_create_mode);
+      if (shared_debug) printf(" handle=%d", h);
+      if (SHARED_INVALID == h) continue;                /* segment already accupied */
+      bp = (BLKHEAD *)shmat(h, 0, 0);                   /* try attach */
+      if (shared_debug) printf(" p=%p", bp);
+      if (((BLKHEAD *)SHARED_INVALID) == bp)            /* cannot attach, delete segment, try with another key */
+        { shmctl(h, IPC_RMID, 0);
+          continue;
+        }                                               /* now create semaphor counting number of processes attached */
+      if (SHARED_INVALID == (shared_gt[idx].sem = semget(key, 1, IPC_CREAT | IPC_EXCL | shared_create_mode)))
+        { shmdt((void *)bp);                            /* cannot create segment, delete everything */
+          shmctl(h, IPC_RMID, 0);
+          continue;                                     /* try with another key */
+        }
+      if (shared_debug) printf(" sem=%d", shared_gt[idx].sem);
+      if (shared_attach_process(shared_gt[idx].sem))    /* try attach process */
+        { semctl(shared_gt[idx].sem, 0, IPC_RMID, filler);      /* destroy semaphore */
+          shmdt((char *)bp);                            /* detach shared mem segment */
+          shmctl(h, IPC_RMID, 0);                       /* destroy shared mem segment */
+          continue;                                     /* try with another key */
+        }
+      bp->s.tflag = BLOCK_SHARED;                       /* fill in data in segment's header (this is really not necessary) */
+      bp->s.ID[0] = SHARED_ID_0;
+      bp->s.ID[1] = SHARED_ID_1;
+      bp->s.handle = idx;                               /* used in yorick */
+      if (mode & SHARED_RESIZE)
+        { if (shmdt((char *)bp)) r = SHARED_IPCERR;     /* if segment is resizable, then detach segment */
+          shared_lt[idx].p = NULL;
+        }
+      else  { shared_lt[idx].p = bp; }
+      shared_lt[idx].tcnt = 1;                          /* one thread using segment */
+      shared_lt[idx].lkcnt = 0;                         /* no locks at the moment */
+      shared_lt[idx].seekpos = 0L;                      /* r/w pointer positioned at beg of block */
+      shared_gt[idx].handle = h;                        /* fill in data in global table */
+      shared_gt[idx].size = size;
+      shared_gt[idx].attr = mode;
+      shared_gt[idx].semkey = key;
+      shared_gt[idx].key = key;
+      shared_gt[idx].nprocdebug = 0;
+
+      break;
+    }
+   shared_demux(idx, SHARED_RDWRITE);                   /* hope this will not fail */
+   return(idx);
+ }
+
+
+int     shared_attach(int idx)
+ { int r, r2;
+
+   if (SHARED_OK != (r = shared_mux(idx, SHARED_RDWRITE | SHARED_WAIT))) return(r);
+   if (SHARED_OK != (r = shared_map(idx)))
+     { shared_demux(idx, SHARED_RDWRITE);
+       return(r);
+     }
+   if (shared_attach_process(shared_gt[idx].sem))       /* try attach process */
+     { shmdt((char *)(shared_lt[idx].p));               /* cannot attach process, detach everything */
+       shared_lt[idx].p = NULL;
+       shared_demux(idx, SHARED_RDWRITE);
+       return(SHARED_BADARG);
+     }
+   shared_lt[idx].tcnt++;                               /* one more thread is using segment */
+   if (shared_gt[idx].attr & SHARED_RESIZE)             /* if resizeable, detach and return special pointer */
+     { if (shmdt((char *)(shared_lt[idx].p))) r = SHARED_IPCERR;  /* if segment is resizable, then detach segment */
+       shared_lt[idx].p = NULL;
+     }
+   shared_lt[idx].seekpos = 0L;                         /* r/w pointer positioned at beg of block */
+   r2 = shared_demux(idx, SHARED_RDWRITE);
+   return(r ? r : r2);
+ }
+
+
+
+static int      shared_check_locked_index(int idx)      /* verify that given idx is valid */ 
+ { int r;
+
+   if (0 == shared_init_called)                         /* delayed initialization */
+     { if (SHARED_OK != (r = shared_init(0))) return(r);
+
+     }
+   if ((idx < 0) || (idx >= shared_maxseg)) return(SHARED_BADARG);
+   if (NULL == shared_lt[idx].p) return(SHARED_BADARG); /* NULL pointer, not attached ?? */
+   if (0 == shared_lt[idx].lkcnt) return(SHARED_BADARG); /* not locked ?? */
+   if ((SHARED_ID_0 != (shared_lt[idx].p)->s.ID[0]) || (SHARED_ID_1 != (shared_lt[idx].p)->s.ID[1]) || 
+       (BLOCK_SHARED != (shared_lt[idx].p)->s.tflag))   /* invalid data in segment */
+     return(SHARED_BADARG);
+   return(SHARED_OK);
+ }
+
+
+
+static int      shared_map(int idx)                     /* map all tables for given idx, check for validity */
+ { int h;                                               /* have to obtain excl. access before calling shared_map */
+   BLKHEAD *bp;
+
+   if ((idx < 0) || (idx >= shared_maxseg)) return(SHARED_BADARG);
+   if (SHARED_INVALID == shared_gt[idx].key)  return(SHARED_BADARG);
+   if (SHARED_INVALID == (h = shmget(shared_gt[idx].key, 1, shared_create_mode)))  return(SHARED_BADARG);
+   if (((BLKHEAD *)SHARED_INVALID) == (bp = (BLKHEAD *)shmat(h, 0, 0)))  return(SHARED_BADARG);
+   if ((SHARED_ID_0 != bp->s.ID[0]) || (SHARED_ID_1 != bp->s.ID[1]) || (BLOCK_SHARED != bp->s.tflag) || (h != shared_gt[idx].handle))
+     { shmdt((char *)bp);                               /* invalid segment, detach everything */
+       return(SHARED_BADARG);
+
+     }
+   if (shared_gt[idx].sem != semget(shared_gt[idx].semkey, 1, shared_create_mode)) /* check if sema is still there */
+     { shmdt((char *)bp);                               /* cannot attach semaphore, detach everything */
+       return(SHARED_BADARG);
+     }
+   shared_lt[idx].p = bp;                               /* store pointer to shmem data */
+   return(SHARED_OK);
+ }
+
+
+static  int     shared_validate(int idx, int mode)      /* use intrnally inside crit.sect !!! */
+ { int r;
+
+   if (SHARED_OK != (r = shared_mux(idx, mode)))  return(r);            /* idx checked by shared_mux */
+   if (NULL == shared_lt[idx].p)
+     if (SHARED_OK != (r = shared_map(idx)))
+       { shared_demux(idx, mode); 
+         return(r);
+       }
+   if ((SHARED_ID_0 != (shared_lt[idx].p)->s.ID[0]) || (SHARED_ID_1 != (shared_lt[idx].p)->s.ID[1]) || (BLOCK_SHARED != (shared_lt[idx].p)->s.tflag))
+     { shared_demux(idx, mode);
+       return(r);
+     }
+   return(SHARED_OK);
+ }
+
+
+SHARED_P shared_realloc(int idx, long newsize)  /* realloc shared memory segment */
+ { int h, key, i, r;
+   BLKHEAD *bp;
+   long transfersize;
+
+   r = SHARED_OK;
+   if (newsize < 0) return(NULL);
+   if (shared_check_locked_index(idx)) return(NULL);
+   if (0 == (shared_gt[idx].attr & SHARED_RESIZE)) return(NULL);
+   if (-1 != shared_lt[idx].lkcnt) return(NULL); /* check for RW lock */
+   if (shared_adjust_size(shared_gt[idx].size) == shared_adjust_size(newsize))
+     { shared_gt[idx].size = newsize;
+
+       return((SHARED_P)((shared_lt[idx].p) + 1));
+     }
+   for (i = 0; ; i++)
+    { if (i >= shared_range)  return(NULL);     /* table full, signal error & exit */
+      key = shared_kbase + ((i + shared_get_hash(newsize, idx)) % shared_range);
+      h = shmget(key, shared_adjust_size(newsize), IPC_CREAT | IPC_EXCL | shared_create_mode);
+      if (SHARED_INVALID == h) continue;        /* segment already accupied */
+      bp = (BLKHEAD *)shmat(h, 0, 0);           /* try attach */
+      if (((BLKHEAD *)SHARED_INVALID) == bp)    /* cannot attach, delete segment, try with another key */
+        { shmctl(h, IPC_RMID, 0);
+          continue;
+        }
+      *bp = *(shared_lt[idx].p);                /* copy header, then data */
+      transfersize = ((newsize < shared_gt[idx].size) ? newsize : shared_gt[idx].size);
+      if (transfersize > 0)
+        memcpy((void *)(bp + 1), (void *)((shared_lt[idx].p) + 1), transfersize);
+      if (shmdt((char *)(shared_lt[idx].p))) r = SHARED_IPCERR; /* try to detach old segment */
+      if (shmctl(shared_gt[idx].handle, IPC_RMID, 0)) if (SHARED_OK == r) r = SHARED_IPCERR;  /* destroy old shared memory segment */
+      shared_gt[idx].size = newsize;            /* signal new size */
+      shared_gt[idx].handle = h;                /* signal new handle */
+      shared_gt[idx].key = key;                 /* signal new key */
+      shared_lt[idx].p = bp;
+      break;
+    }
+   return((SHARED_P)(bp + 1));
+ }
+
+
+int     shared_free(int idx)                    /* detach segment, if last process & !PERSIST, destroy segment */
+ { int cnt, r, r2;
+
+   if (SHARED_OK != (r = shared_validate(idx, SHARED_RDWRITE | SHARED_WAIT))) return(r);
+   if (SHARED_OK != (r = shared_detach_process(shared_gt[idx].sem)))    /* update number of processes using segment */
+     { shared_demux(idx, SHARED_RDWRITE);
+       return(r);
+     }
+   shared_lt[idx].tcnt--;                       /* update number of threads using segment */
+   if (shared_lt[idx].tcnt > 0)  return(shared_demux(idx, SHARED_RDWRITE));  /* if more threads are using segment we are done */
+   if (shmdt((char *)(shared_lt[idx].p)))       /* if, we are the last thread, try to detach segment */
+     { shared_demux(idx, SHARED_RDWRITE);
+       return(SHARED_IPCERR);
+     }
+   shared_lt[idx].p = NULL;                     /* clear entry in local table */
+   shared_lt[idx].seekpos = 0L;                 /* r/w pointer positioned at beg of block */
+   if (-1 == (cnt = shared_process_count(shared_gt[idx].sem))) /* get number of processes hanging on segment */
+     { shared_demux(idx, SHARED_RDWRITE);
+       return(SHARED_IPCERR);
+     }
+   if ((0 == cnt) && (0 == (shared_gt[idx].attr & SHARED_PERSIST)))  r = shared_destroy_entry(idx); /* no procs on seg, destroy it */
+   r2 = shared_demux(idx, SHARED_RDWRITE);
+   return(r ? r : r2);
+ }
+
+
+SHARED_P shared_lock(int idx, int mode)         /* lock given segment for exclusive access */
+ { int r;
+
+   if (shared_mux(idx, mode))  return(NULL);    /* idx checked by shared_mux */
+   if (0 != shared_lt[idx].lkcnt)               /* are we already locked ?? */
+     if (SHARED_OK != (r = shared_map(idx)))
+       { shared_demux(idx, mode); 
+         return(NULL);
+       }
+   if (NULL == shared_lt[idx].p)                /* stupid pointer ?? */
+     if (SHARED_OK != (r = shared_map(idx)))
+       { shared_demux(idx, mode); 
+         return(NULL);
+       }
+   if ((SHARED_ID_0 != (shared_lt[idx].p)->s.ID[0]) || (SHARED_ID_1 != (shared_lt[idx].p)->s.ID[1]) || (BLOCK_SHARED != (shared_lt[idx].p)->s.tflag))
+     { shared_demux(idx, mode);
+       return(NULL);
+     }
+   if (mode & SHARED_RDWRITE)
+     { shared_lt[idx].lkcnt = -1;
+
+       shared_gt[idx].nprocdebug++;
+     }
+
+   else shared_lt[idx].lkcnt++;
+   shared_lt[idx].seekpos = 0L;                 /* r/w pointer positioned at beg of block */
+   return((SHARED_P)((shared_lt[idx].p) + 1));
+ }
+
+
+int     shared_unlock(int idx)                  /* unlock given segment, assumes seg is locked !! */
+ { int r, r2, mode;
+
+   if (SHARED_OK != (r = shared_check_locked_index(idx))) return(r);
+   if (shared_lt[idx].lkcnt > 0)
+     { shared_lt[idx].lkcnt--;                  /* unlock read lock */
+       mode = SHARED_RDONLY;
+     }
+   else
+     { shared_lt[idx].lkcnt = 0;                /* unlock write lock */
+       shared_gt[idx].nprocdebug--;
+       mode = SHARED_RDWRITE;
+     }
+   if (0 == shared_lt[idx].lkcnt) if (shared_gt[idx].attr & SHARED_RESIZE)
+     { if (shmdt((char *)(shared_lt[idx].p))) r = SHARED_IPCERR; /* segment is resizable, then detach segment */
+       shared_lt[idx].p = NULL;                 /* signal detachment in local table */
+     }
+   r2 = shared_demux(idx, mode);                /* unlock segment, rest is only parameter checking */
+   return(r ? r : r2);
+ }
+
+                /* API routines - support and info routines */
+
+
+int     shared_attr(int idx)                    /* get the attributes of the shared memory segment */
+ { int r;
+
+   if (shared_check_locked_index(idx)) return(SHARED_INVALID);
+   r = shared_gt[idx].attr;
+   return(r);
+ }
+
+
+int     shared_set_attr(int idx, int newattr)   /* get the attributes of the shared memory segment */
+ { int r;
+
+   if (shared_check_locked_index(idx)) return(SHARED_INVALID);
+   if (-1 != shared_lt[idx].lkcnt) return(SHARED_INVALID); /* ADDED - check for RW lock */
+   r = shared_gt[idx].attr;
+   shared_gt[idx].attr = newattr;
+   return(r);
+
+ }
+
+
+int     shared_set_debug(int mode)              /* set/reset debug mode */
+ { int r = shared_debug;
+
+   shared_debug = mode;
+   return(r);
+ }
+
+
+int     shared_set_createmode(int mode)          /* set/reset debug mode */
+ { int r = shared_create_mode;
+
+   shared_create_mode = mode;
+   return(r);
+ }
+
+
+
+
+int     shared_list(int id)
+ { int i, r;
+
+   if (NULL == shared_gt) return(SHARED_NOTINIT);       /* not initialized */
+   if (NULL == shared_lt) return(SHARED_NOTINIT);       /* not initialized */
+   if (shared_debug) printf("shared_list:");
+   r = SHARED_OK;
+   printf(" Idx    Key   Nproc   Size   Flags\n");
+   printf("==============================================\n");
+   for (i=0; i<shared_maxseg; i++)
+    { if (-1 != id) if (i != id) continue;
+      if (SHARED_INVALID == shared_gt[i].key) continue; /* unused slot */
+      switch (shared_mux(i, SHARED_NOWAIT | SHARED_RDONLY)) /* acquire exclusive access to segment, but do not wait */
+
+       { case SHARED_AGAIN:
+                printf("!%3d %08lx %4d  %8d", i, (unsigned long int)shared_gt[i].key,
+                                shared_gt[i].nprocdebug, shared_gt[i].size);
+                if (SHARED_RESIZE & shared_gt[i].attr) printf(" RESIZABLE");
+                if (SHARED_PERSIST & shared_gt[i].attr) printf(" PERSIST");
+                printf("\n");
+                break;
+         case SHARED_OK:
+                printf(" %3d %08lx %4d  %8d", i, (unsigned long int)shared_gt[i].key,
+
+                                shared_gt[i].nprocdebug, shared_gt[i].size);
+                if (SHARED_RESIZE & shared_gt[i].attr) printf(" RESIZABLE");
+                if (SHARED_PERSIST & shared_gt[i].attr) printf(" PERSIST");
+                printf("\n");
+                shared_demux(i, SHARED_RDONLY);
+                break;
+         default:
+                continue;
+       }
+    }
+   if (shared_debug) printf(" done\n");
+   return(r);                                           /* table full */
+ }
+
+
+int     shared_uncond_delete(int id)
+ { int i, r;
+
+   if (NULL == shared_gt) return(SHARED_NOTINIT);       /* not initialized */
+   if (NULL == shared_lt) return(SHARED_NOTINIT);       /* not initialized */
+   if (shared_debug) printf("shared_uncond_delete:");
+   r = SHARED_OK;
+   for (i=0; i<shared_maxseg; i++)
+    { if (-1 != id) if (i != id) continue;
+      if (shared_attach(i))
+        { if (-1 != id) printf("no such handle\n");
+          continue;
+        }
+      printf("handle %d:", i);
+      if (NULL == shared_lock(i, SHARED_RDWRITE | SHARED_NOWAIT)) 
+        { printf(" cannot lock in RW mode, not deleted\n");
+          continue;
+        }
+      if (shared_set_attr(i, SHARED_RESIZE) >= SHARED_ERRBASE)
+        { printf(" cannot clear PERSIST attribute");
+        }
+      if (shared_free(i))
+        { printf(" delete failed\n");
+        }
+      else
+        { printf(" deleted\n");
+        }
+    }
+   if (shared_debug) printf(" done\n");
+   return(r);                                           /* table full */
+ }
+
+
+/************************* CFITSIO DRIVER FUNCTIONS ***************************/
+
+int     smem_init(void)
+ { return(0);
+ }
+
+int     smem_shutdown(void)
+
+ { if (shared_init_called) shared_cleanup();
+   return(0);
+ }
+
+int     smem_setoptions(int option)
+ { option = 0;
+   return(0);
+ }
+
+
+int     smem_getoptions(int *options)
+ { if (NULL == options) return(SHARED_NULPTR);
+   *options = 0;
+   return(0);
+ }
+
+int     smem_getversion(int *version)
+ { if (NULL == version) return(SHARED_NULPTR);
+   *version = 10;
+   return(0);
+ }
+
+
+int     smem_open(char *filename, int rwmode, int *driverhandle)
+ { int h, nitems, r;
+   DAL_SHM_SEGHEAD *sp;
+
+
+   if (NULL == filename) return(SHARED_NULPTR);
+   if (NULL == driverhandle) return(SHARED_NULPTR);
+   nitems = sscanf(filename, "h%d", &h);
+   if (1 != nitems) return(SHARED_BADARG);
+
+   if (SHARED_OK != (r = shared_attach(h))) return(r);
+
+   if (NULL == (sp = (DAL_SHM_SEGHEAD *)shared_lock(h,
+                ((READWRITE == rwmode) ? SHARED_RDWRITE : SHARED_RDONLY))))
+     {  shared_free(h);
+        return(SHARED_BADARG);
+     }
+
+   if ((h != sp->h) || (DAL_SHM_SEGHEAD_ID != sp->ID))
+     { shared_unlock(h);
+       shared_free(h);
+
+       return(SHARED_BADARG);
+     }
+
+   *driverhandle = h;
+   return(0);
+ }
+
+
+int     smem_create(char *filename, int *driverhandle)
+ { DAL_SHM_SEGHEAD *sp;
+   int h, sz, nitems;
+
+   if (NULL == filename) return(SHARED_NULPTR);         /* currently ignored */
+   if (NULL == driverhandle) return(SHARED_NULPTR);
+   nitems = sscanf(filename, "h%d", &h);
+   if (1 != nitems) return(SHARED_BADARG);
+
+   if (SHARED_INVALID == (h = shared_malloc(sz = 2880 + sizeof(DAL_SHM_SEGHEAD), 
+                        SHARED_RESIZE | SHARED_PERSIST, h)))
+     return(SHARED_NOMEM);
+
+   if (NULL == (sp = (DAL_SHM_SEGHEAD *)shared_lock(h, SHARED_RDWRITE)))
+     { shared_free(h);
+       return(SHARED_BADARG);
+     }
+
+   sp->ID = DAL_SHM_SEGHEAD_ID;
+   sp->h = h;
+   sp->size = sz;
+   sp->nodeidx = -1;
+
+   *driverhandle = h;
+   
+   return(0);
+ }
+
+
+int     smem_close(int driverhandle)
+ { int r;
+
+   if (SHARED_OK != (r = shared_unlock(driverhandle))) return(r);
+   return(shared_free(driverhandle));
+ }
+
+int     smem_remove(char *filename)
+ { int nitems, h, r;
+
+   if (NULL == filename) return(SHARED_NULPTR);
+   nitems = sscanf(filename, "h%d", &h);
+   if (1 != nitems) return(SHARED_BADARG);
+
+   if (0 == shared_check_locked_index(h))       /* are we locked ? */
+
+     { if (-1 != shared_lt[h].lkcnt)            /* are we locked RO ? */
+         { if (SHARED_OK != (r = shared_unlock(h))) return(r);  /* yes, so relock in RW */
+           if (NULL == shared_lock(h, SHARED_RDWRITE)) return(SHARED_BADARG);
+         }
+
+     }
+   else                                         /* not locked */
+     { if (SHARED_OK != (r = smem_open(filename, READWRITE, &h)))
+         return(r);                             /* so open in RW mode */
+     }
+
+   shared_set_attr(h, SHARED_RESIZE);           /* delete PERSIST attribute */
+   return(smem_close(h));                       /* detach segment (this will delete it) */
+ }
+
+int     smem_size(int driverhandle, OFF_T *size)
+ {
+   if (NULL == size) return(SHARED_NULPTR);
+   if (shared_check_locked_index(driverhandle)) return(SHARED_INVALID);
+   *size = (OFF_T) (shared_gt[driverhandle].size - sizeof(DAL_SHM_SEGHEAD));
+   return(0);
+ }
+
+int     smem_flush(int driverhandle)
+ {
+   if (shared_check_locked_index(driverhandle)) return(SHARED_INVALID);
+   return(0);
+ }
+
+int     smem_seek(int driverhandle, OFF_T offset)
+ {
+   if (offset < 0) return(SHARED_BADARG);
+   if (shared_check_locked_index(driverhandle)) return(SHARED_INVALID);
+   shared_lt[driverhandle].seekpos = offset;
+   return(0);
+ }
+
+int     smem_read(int driverhandle, void *buffer, long nbytes)
+ {
+   if (NULL == buffer) return(SHARED_NULPTR);
+   if (shared_check_locked_index(driverhandle)) return(SHARED_INVALID);
+   if (nbytes < 0) return(SHARED_BADARG);
+   if ((shared_lt[driverhandle].seekpos + nbytes) > shared_gt[driverhandle].size)
+     return(SHARED_BADARG);             /* read beyond EOF */
+
+   memcpy(buffer,
+          ((char *)(((DAL_SHM_SEGHEAD *)(shared_lt[driverhandle].p + 1)) + 1)) +
+                shared_lt[driverhandle].seekpos,
+          nbytes);
+
+   shared_lt[driverhandle].seekpos += nbytes;
+   return(0);
+ }
+
+int     smem_write(int driverhandle, void *buffer, long nbytes)
+ {
+   if (NULL == buffer) return(SHARED_NULPTR);
+   if (shared_check_locked_index(driverhandle)) return(SHARED_INVALID);
+   if (-1 != shared_lt[driverhandle].lkcnt) return(SHARED_INVALID); /* are we locked RW ? */
+
+   if (nbytes < 0) return(SHARED_BADARG);
+   if ((unsigned long)(shared_lt[driverhandle].seekpos + nbytes) > (unsigned long)(shared_gt[driverhandle].size - sizeof(DAL_SHM_SEGHEAD)))
+     {                  /* need to realloc shmem */
+       if (NULL == shared_realloc(driverhandle, shared_lt[driverhandle].seekpos + nbytes + sizeof(DAL_SHM_SEGHEAD)))
+         return(SHARED_NOMEM);
+     }
+
+   memcpy(((char *)(((DAL_SHM_SEGHEAD *)(shared_lt[driverhandle].p + 1)) + 1)) +
+                shared_lt[driverhandle].seekpos,
+          buffer,
+          nbytes);
+
+   shared_lt[driverhandle].seekpos += nbytes;
+   return(0);
+ }
+#endif