/* * Copyright (C) 1997 NCSA * All rights reserved. * * Programmer: Robb Matzke * Wednesday, October 22, 1997 * * Purpose: This is the Posix section-2 I/O subclass of H5Flow. * * Notes: This driver keeps track of its own file position in order to * minimize the number of calls to lseek(). We assume that * opening a file sets the current file position to the beginning * and that read() and write() modify the file position as * expected when they return successfully (unsuccessful return * leaves the file position undefined). */ #include #include #include #include #include #include #define PABLO_MASK H5F_sec2 static hbool_t interface_initialize_g = FALSE; #define INTERFACE_INIT NULL static H5F_low_t *H5F_sec2_open (const char *name, uintn flags, H5F_search_t*); static herr_t H5F_sec2_close (H5F_low_t *lf); static herr_t H5F_sec2_read (H5F_low_t *lf, const haddr_t *addr, size_t size, uint8 *buf); static herr_t H5F_sec2_write (H5F_low_t *lf, const haddr_t *addr, size_t size, const uint8 *buf); const H5F_low_class_t H5F_LOW_SEC2[1] = {{ NULL, /* access method */ H5F_sec2_open, /* open method */ H5F_sec2_close, /* close method */ H5F_sec2_read, /* read method */ H5F_sec2_write, /* write method */ NULL, /* flush method */ NULL, /* extend method */ }}; /*------------------------------------------------------------------------- * Function: H5F_sec2_open * * Purpose: Opens a file with name NAME. The FLAGS are a bit field with * the possible values defined in H5F_low_open(). * * Errors: * IO CANTOPENFILE Open failed. * * Return: Success: Low-level file pointer * * Failure: NULL * * Programmer: Robb Matzke * Wednesday, October 22, 1997 * * Modifications: * *------------------------------------------------------------------------- */ static H5F_low_t * H5F_sec2_open (const char *name, uintn flags, H5F_search_t *key/*out*/) { uintn oflags; H5F_low_t *lf = NULL; int fd; struct stat sb; FUNC_ENTER (H5F_sec2_open, NULL); oflags = (flags & H5F_ACC_WRITE) ? O_RDWR : O_RDONLY; oflags |= (flags & H5F_ACC_CREAT) ? O_CREAT : 0; oflags |= (flags & H5F_ACC_EXCL) ? O_EXCL : 0; oflags |= (flags & H5F_ACC_TRUNC) ? O_TRUNC : 0; if ((fd=open (name, oflags, 0666))<0) { HRETURN_ERROR (H5E_IO, H5E_CANTOPENFILE, NULL, "open failed"); } lf = H5MM_xcalloc (1, sizeof(H5F_low_t)); lf->u.sec2.fd = fd; lf->u.sec2.op = H5F_OP_SEEK; lf->u.sec2.cur = 0; fstat (fd, &sb); lf->eof.offset = sb.st_size; if (key) { key->dev = sb.st_dev; key->ino = sb.st_ino; } FUNC_LEAVE (lf); } /*------------------------------------------------------------------------- * Function: H5F_sec2_close * * Purpose: Closes a file. * * Errors: * IO CLOSEERROR Close failed. * * Return: Success: SUCCEED * * Failure: FAIL * * Programmer: Robb Matzke * Wednesday, October 22, 1997 * * Modifications: * *------------------------------------------------------------------------- */ static herr_t H5F_sec2_close (H5F_low_t *lf) { FUNC_ENTER (H5F_sec2_close, FAIL); if (close (lf->u.sec2.fd)<0) { HRETURN_ERROR (H5E_IO, H5E_CLOSEERROR, FAIL, "close failed"); } lf->u.sec2.fd = -1; FUNC_LEAVE (SUCCEED); } /*------------------------------------------------------------------------- * Function: H5F_sec2_read * * Purpose: Reads SIZE bytes beginning at address ADDR in file LF and * places them in buffer BUF. Reading past the logical or * physical end of file returns zeros instead of failing. * * Errors: * IO READERROR Read failed. * IO SEEKERROR Lseek failed. * * Return: Success: SUCCEED * * Failure: FAIL * * Programmer: Robb Matzke * Wednesday, October 22, 1997 * * Modifications: * *------------------------------------------------------------------------- */ static herr_t H5F_sec2_read (H5F_low_t *lf, const haddr_t *addr, size_t size, uint8 *buf) { ssize_t n; off_t offset; FUNC_ENTER (H5F_sec2_read, FAIL); /* Check for overflow */ offset = addr->offset; assert ("address overflowed" && offset==addr->offset); assert ("overflow" && offset+size>=offset); /* Check easy cases */ if (0==size) HRETURN (SUCCEED); if (offset>=lf->eof.offset) { HDmemset (buf, 0, size); HRETURN (SUCCEED); } /* * Optimize seeking. If that optimization is disabled then always call * lseek(). */ if (!H5F_OPT_SEEK || lf->u.sec2.op==H5F_OP_UNKNOWN || lf->u.sec2.cur!=offset) { if (lseek (lf->u.sec2.fd, offset, SEEK_SET)<0) { HRETURN_ERROR (H5E_IO, H5E_SEEKERROR, FAIL, "lseek failed"); } lf->u.sec2.cur = offset; } /* * Read zeros past the logical end of file (physical is handled below) */ if ((size_t)offset+size>lf->eof.offset) { size_t nbytes = (size_t)offset+size - lf->eof.offset; HDmemset (buf+size-nbytes, 0, nbytes); size -= nbytes; } /* * Read the data. If a read error occurs then set the last file operation * to UNKNOWN because the file position isn't guaranteed by Posix. */ if ((n=read (lf->u.sec2.fd, buf, size))<0) { lf->u.sec2.op = H5F_OP_UNKNOWN; HRETURN_ERROR (H5E_IO, H5E_READERROR, FAIL, "read failed"); } else if (nu.sec2.op = H5F_OP_READ; lf->u.sec2.cur = offset + n; assert ("address overflowed" && lf->u.sec2.cur>=offset); FUNC_LEAVE (SUCCEED); } /*------------------------------------------------------------------------- * Function: H5F_sec2_write * * Purpose: Writes SIZE bytes from the beginning of BUF into file LF at * file address ADDR. * * Errors: * IO SEEKERROR Lseek failed. * IO WRITEERROR Write failed. * * Return: Success: SUCCEED * * Failure: FAIL * * Programmer: Robb Matzke * Wednesday, October 22, 1997 * * Modifications: * *------------------------------------------------------------------------- */ static herr_t H5F_sec2_write (H5F_low_t *lf, const haddr_t *addr, size_t size, const uint8 *buf) { off_t offset; FUNC_ENTER (H5F_sec2_write, FAIL); /* Check for overflow */ offset = addr->offset; assert ("address overflowed" && offset==addr->offset); assert ("overflow" && offset+size>=offset); /* * Optimize seeking. If that optimization is disabled then always call * lseek(). */ if (!H5F_OPT_SEEK || lf->u.sec2.op==H5F_OP_UNKNOWN || lf->u.sec2.cur!=offset) { if (lseek (lf->u.sec2.fd, offset, SEEK_SET)<0) { HRETURN_ERROR (H5E_IO, H5E_SEEKERROR, FAIL, "lseek failed"); } lf->u.sec2.cur = offset; } /* * Write the data to the file. If the write failed then set the * operation back to UNKNOWN since Posix doesn't gurantee its value. */ if (size != write (lf->u.sec2.fd, buf, size)) { lf->u.sec2.op = H5F_OP_UNKNOWN; HRETURN_ERROR (H5E_IO, H5E_WRITEERROR, FAIL, "write failed"); } /* * Update the file position. */ lf->u.sec2.op = H5F_OP_WRITE; lf->u.sec2.cur = offset + size; assert ("address overflowed" && lf->u.sec2.cur>=offset); FUNC_LEAVE (SUCCEED); }