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/******************************************************************************
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* *
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* License Agreement *
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* *
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* Copyright (c) 2006 Altera Corporation, San Jose, California, USA. *
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* All rights reserved. *
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* *
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* Permission is hereby granted, free of charge, to any person obtaining a *
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* copy of this software and associated documentation files (the "Software"), *
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* to deal in the Software without restriction, including without limitation *
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* the rights to use, copy, modify, merge, publish, distribute, sublicense, *
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* and/or sell copies of the Software, and to permit persons to whom the *
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* Software is furnished to do so, subject to the following conditions: *
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* *
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* The above copyright notice and this permission notice shall be included in *
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* all copies or substantial portions of the Software. *
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* *
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR *
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, *
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE *
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER *
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING *
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER *
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* DEALINGS IN THE SOFTWARE. *
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* *
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* This agreement shall be governed in all respects by the laws of the State *
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* of California and by the laws of the United States of America. *
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* *
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* Altera does not recommend, suggest or require that this reference design *
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* file be used in conjunction or combination with any other product. *
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******************************************************************************/
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#include <unistd.h>
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#include <fcntl.h>
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#include "sys/alt_errno.h"
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#include "sys/alt_warning.h"
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#include "priv/alt_file.h"
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#include "os/alt_syscall.h"
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/*
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* The read() system call is used to read a block of data from a file or device.
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* This function simply vectors the request to the device driver associated
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* with the input file descriptor "file".
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*
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* ALT_READ is mapped onto the read() system call in alt_syscall.h
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*/
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#ifdef ALT_USE_DIRECT_DRIVERS
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#include "system.h"
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#include "sys/alt_driver.h"
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/*
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* Provide minimal version that just reads from the stdin device when provided.
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*/
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int ALT_READ (int file, void *ptr, size_t len)
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{
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#ifdef ALT_STDIN_PRESENT
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ALT_DRIVER_READ_EXTERNS(ALT_STDIN_DEV);
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#endif
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#if !defined(ALT_STDIN_PRESENT)
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/* Generate a link time warning, should this function ever be called. */
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ALT_STUB_WARNING(read);
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#endif
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switch (file) {
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#ifdef ALT_STDIN_PRESENT
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case 0: /* stdin file descriptor */
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return ALT_DRIVER_READ(ALT_STDIN_DEV, ptr, len, 0);
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#endif /* ALT_STDIN_PRESENT */
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default:
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ALT_ERRNO = EBADFD;
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return -1;
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}
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}
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#else /* !ALT_USE_DIRECT_DRIVERS */
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int ALT_READ (int file, void *ptr, size_t len)
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{
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alt_fd* fd;
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int rval;
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/*
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* A common error case is that when the file descriptor was created, the call
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* to open() failed resulting in a negative file descriptor. This is trapped
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* below so that we don't try and process an invalid file descriptor.
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*/
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fd = (file < 0) ? NULL : &alt_fd_list[file];
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if (fd)
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{
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/*
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* If the file has not been opened with read access, or if the driver does
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* not provide an implementation of read(), generate an error. Otherwise
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* call the drivers read() function to process the request.
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*/
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if (((fd->fd_flags & O_ACCMODE) != O_WRONLY) &&
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(fd->dev->read))
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{
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if ((rval = fd->dev->read(fd, ptr, len)) < 0)
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{
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ALT_ERRNO = -rval;
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return -1;
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}
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return rval;
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}
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else
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{
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ALT_ERRNO = EACCES;
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}
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}
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else
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{
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ALT_ERRNO = EBADFD;
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}
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return -1;
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}
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#endif /* ALT_USE_DIRECT_DRIVERS */
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