src/libs/ck-libs/ampi/romio/adio/ad_bgl/ad_bgl_getsh.c

   1 /* ---------------------------------------------------------------- */
   2 /* (C)Copyright IBM Corp.  2007, 2008                               */
   3 /* ---------------------------------------------------------------- */
   4 /**
   5  * \file ad_bgl_getsh.c
   6  * \brief ???
   7  */
   8
   9 /* -*- Mode: C; c-basic-offset:4 ; -*- */
  10 /*
  11  *   Copyright (C) 1997 University of Chicago.
  12  *   See COPYRIGHT notice in top-level directory.
  13  */
  14
  15 #include "ad_bgl.h"
  16
  17 /* returns the current location of the shared_fp in terms of the
  18    no. of etypes relative to the current view, and also increments the
  19    shared_fp by the number of etypes to be accessed (incr) in the read
  20    or write following this function. */
  21
  22 void ADIOI_BGL_Get_shared_fp(ADIO_File fd, int incr, ADIO_Offset *shared_fp,
  23                          int *error_code)
  24 {
  25     ADIO_Offset new_fp;
  26     int err;
  27     MPI_Comm dupcommself;
  28     static char myname[] = "ADIOI_BGL_GET_SHARED_FP";
  29
  30     if (fd->shared_fp_fd == ADIO_FILE_NULL) {
  31         MPI_Comm_dup(MPI_COMM_SELF, &dupcommself);
  32         fd->shared_fp_fd = ADIO_Open(MPI_COMM_SELF,
  33                                      dupcommself,
  34                                      fd->shared_fp_fname,
  35                                      fd->file_system,
  36                                      fd->fns,
  37                                      ADIO_CREATE | ADIO_RDWR | ADIO_DELETE_ON_CLOSE,
  38                                      0,
  39                                      MPI_BYTE,
  40                                      MPI_BYTE,
  41                                      MPI_INFO_NULL,
  42                                      ADIO_PERM_NULL,
  43                                      error_code);
  44         if (*error_code != MPI_SUCCESS) return;
  45         *shared_fp = 0;
  46         ADIOI_WRITE_LOCK(fd->shared_fp_fd, 0, SEEK_SET, sizeof(ADIO_Offset));
  47         err = read(fd->shared_fp_fd->fd_sys, shared_fp, sizeof(ADIO_Offset));
  48         /* if the file is empty, the above read may return error
  49            (reading beyond end of file). In that case, shared_fp = 0,
  50            set above, is the correct value. */
  51     }
  52     else {
  53         ADIOI_WRITE_LOCK(fd->shared_fp_fd, 0, SEEK_SET, sizeof(ADIO_Offset));
  54
  55         err = lseek(fd->shared_fp_fd->fd_sys, 0, SEEK_SET);
  56         if (err == 0) {
  57             err = read(fd->shared_fp_fd->fd_sys, shared_fp,
  58                        sizeof(ADIO_Offset));
  59         }
  60         if (err == -1) {
  61             ADIOI_UNLOCK(fd->shared_fp_fd, 0, SEEK_SET, sizeof(ADIO_Offset));
  62             *error_code = MPIO_Err_create_code(MPI_SUCCESS,
  63                                                MPIR_ERR_RECOVERABLE, myname,
  64                                                __LINE__, MPI_ERR_IO, "**io",
  65                                                "**io %s", strerror(errno));
  66             return;
  67         }
  68     }
  69
  70     new_fp = *shared_fp + incr;
  71
  72     err = lseek(fd->shared_fp_fd->fd_sys, 0, SEEK_SET);
  73     if (err == 0) {
  74         err = write(fd->shared_fp_fd->fd_sys, &new_fp, sizeof(ADIO_Offset));
  75     }
  76     ADIOI_UNLOCK(fd->shared_fp_fd, 0, SEEK_SET, sizeof(ADIO_Offset));
  77     if (err == -1) {
  78         *error_code = MPIO_Err_create_code(MPI_SUCCESS, MPIR_ERR_RECOVERABLE,
  79                                            myname, __LINE__, MPI_ERR_IO,
  80                                            "**io",
  81                                            "**io %s", strerror(errno));
  82     }
  83     else *error_code = MPI_SUCCESS;
  84 }