86 lines
1.8 KiB
C
86 lines
1.8 KiB
C
/*
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* Copyright (C) 2020 Embecosm Limited
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#include "semihost_fdtable.h"
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#include <errno.h>
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#include <fcntl.h>
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#include <unistd.h>
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#ifndef RISCV_MAX_OPEN_FILES
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#define RISCV_MAX_OPEN_FILES 16
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#endif
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extern int errno;
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extern int _open (const char *, int, ...);
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/* fdtable keeps track of the position of each file and is used to map stdin,
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stdout and stderr to STDIN_FILENO, STDOUT_FILENO and STDERR_FILENO. */
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static struct fdentry fdtable[RISCV_MAX_OPEN_FILES];
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/* Initialize fdtable. A handle of -1 denotes an empty entry. */
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void __attribute__ ((constructor))
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init_semihosting ()
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{
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int handle;
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for (int i=0; i<RISCV_MAX_OPEN_FILES; i++)
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fdtable[i].handle = -1;
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/* Set up std streams. */
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/* stdin. */
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handle = _open (":tt", O_RDONLY);
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fdtable[STDIN_FILENO].handle = handle;
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fdtable[STDIN_FILENO].pos = 0;
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/* stdout. */
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handle = _open (":tt", O_WRONLY|O_CREAT|O_TRUNC);
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fdtable[STDOUT_FILENO].handle = handle;
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fdtable[STDOUT_FILENO].pos = 0;
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/* stderr. */
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handle = _open (":tt", O_WRONLY|O_CREAT|O_APPEND);
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fdtable[STDERR_FILENO].handle = handle;
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fdtable[STDERR_FILENO].pos = 0;
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}
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/* Add entry to fdtable. */
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int
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__add_fdentry (int handle)
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{
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for (int i=0; i<RISCV_MAX_OPEN_FILES; i++)
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if (fdtable[i].handle == -1)
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{
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fdtable[i].handle = handle;
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fdtable[i].pos = 0;
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return i;
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}
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/* Too many open files. */
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errno = ENFILE;
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return -1;
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}
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/* Return the fdentry for file or NULL if not found. */
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struct fdentry *
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__get_fdentry (int file)
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{
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if (file<0 || file>=RISCV_MAX_OPEN_FILES || fdtable[file].handle == -1)
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{
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errno = EBADF;
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return NULL;
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}
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return &fdtable[file];
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}
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/* Remove entry from fdtable. */
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void
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__remove_fdentry (int file)
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{
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fdtable[file].handle = -1;
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}
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