331 lines
11 KiB
C
331 lines
11 KiB
C
/* Remote target system call callback support.
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Copyright 1997, 2007, 2008, 2009, 2010 Free Software Foundation, Inc.
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Contributed by Cygnus Solutions.
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This file is part of GDB.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>. */
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/* This interface isn't intended to be specific to any particular kind
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of remote (hardware, simulator, whatever). As such, support for it
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(e.g. sim/common/callback.c) should *not* live in the simulator source
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tree, nor should it live in the gdb source tree. */
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/* There are various ways to handle system calls:
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1) Have a simulator intercept the appropriate trap instruction and
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directly perform the system call on behalf of the target program.
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This is the typical way of handling system calls for embedded targets.
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[Handling system calls for embedded targets isn't that much of an
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oxymoron as running compiler testsuites make use of the capability.]
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This method of system call handling is done when STATE_ENVIRONMENT
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is ENVIRONMENT_USER.
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2) Have a simulator emulate the hardware as much as possible.
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If the program running on the real hardware communicates with some sort
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of target manager, one would want to be able to run this program on the
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simulator as well.
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This method of system call handling is done when STATE_ENVIRONMENT
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is ENVIRONMENT_OPERATING.
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*/
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#ifndef CALLBACK_H
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#define CALLBACK_H
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/* ??? The reason why we check for va_start here should be documented. */
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#ifndef va_start
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#include <ansidecl.h>
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#include <stdarg.h>
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#endif
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/* Needed for enum bfd_endian. */
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#include "bfd.h"
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/* Mapping of host/target values. */
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/* ??? For debugging purposes, one might want to add a string of the
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name of the symbol. */
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typedef struct {
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int host_val;
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int target_val;
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} CB_TARGET_DEFS_MAP;
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#define MAX_CALLBACK_FDS 10
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/* Forward decl for stat/fstat. */
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struct stat;
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typedef struct host_callback_struct host_callback;
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struct host_callback_struct
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{
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int (*close) (host_callback *,int);
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int (*get_errno) (host_callback *);
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int (*isatty) (host_callback *, int);
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int (*lseek) (host_callback *, int, long , int);
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int (*open) (host_callback *, const char*, int mode);
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int (*read) (host_callback *,int, char *, int);
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int (*read_stdin) ( host_callback *, char *, int);
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int (*rename) (host_callback *, const char *, const char *);
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int (*system) (host_callback *, const char *);
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long (*time) (host_callback *, long *);
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int (*unlink) (host_callback *, const char *);
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int (*write) (host_callback *,int, const char *, int);
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int (*write_stdout) (host_callback *, const char *, int);
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void (*flush_stdout) (host_callback *);
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int (*write_stderr) (host_callback *, const char *, int);
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void (*flush_stderr) (host_callback *);
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int (*stat) (host_callback *, const char *, struct stat *);
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int (*fstat) (host_callback *, int, struct stat *);
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int (*lstat) (host_callback *, const char *, struct stat *);
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int (*ftruncate) (host_callback *, int, long);
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int (*truncate) (host_callback *, const char *, long);
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int (*pipe) (host_callback *, int *);
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/* Called by the framework when a read call has emptied a pipe buffer. */
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void (*pipe_empty) (host_callback *, int read_fd, int write_fd);
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/* Called by the framework when a write call makes a pipe buffer
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non-empty. */
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void (*pipe_nonempty) (host_callback *, int read_fd, int write_fd);
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/* When present, call to the client to give it the oportunity to
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poll any io devices for a request to quit (indicated by a nonzero
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return value). */
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int (*poll_quit) (host_callback *);
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/* Used when the target has gone away, so we can close open
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handles and free memory etc etc. */
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int (*shutdown) (host_callback *);
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int (*init) (host_callback *);
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/* depreciated, use vprintf_filtered - Talk to the user on a console. */
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void (*printf_filtered) (host_callback *, const char *, ...);
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/* Talk to the user on a console. */
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void (*vprintf_filtered) (host_callback *, const char *, va_list);
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/* Same as vprintf_filtered but to stderr. */
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void (*evprintf_filtered) (host_callback *, const char *, va_list);
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/* Print an error message and "exit".
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In the case of gdb "exiting" means doing a longjmp back to the main
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command loop. */
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void (*error) (host_callback *, const char *, ...)
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#ifdef __GNUC__
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__attribute__ ((__noreturn__))
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#endif
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;
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int last_errno; /* host format */
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int fdmap[MAX_CALLBACK_FDS];
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/* fd_buddy is used to contruct circular lists of target fds that point to
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the same host fd. A uniquely mapped fd points to itself; for a closed
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one, fd_buddy has the value -1. The host file descriptors for stdin /
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stdout / stderr are never closed by the simulators, so they are put
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in a special fd_buddy circular list which also has MAX_CALLBACK_FDS
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as a member. */
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/* ??? We don't have a callback entry for dup, although it is trival to
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implement now. */
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short fd_buddy[MAX_CALLBACK_FDS+1];
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/* 0 = none, >0 = reader (index of writer),
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<0 = writer (negative index of reader).
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If abs (ispipe[N]) == N, then N is an end of a pipe whose other
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end is closed. */
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short ispipe[MAX_CALLBACK_FDS];
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/* A writer stores the buffer at its index. Consecutive writes
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realloc the buffer and add to the size. The reader indicates the
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read part in its .size, until it has consumed it all, at which
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point it deallocates the buffer and zeroes out both sizes. */
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struct pipe_write_buffer
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{
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int size;
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char *buffer;
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} pipe_buffer[MAX_CALLBACK_FDS];
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/* System call numbers. */
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CB_TARGET_DEFS_MAP *syscall_map;
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/* Errno values. */
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CB_TARGET_DEFS_MAP *errno_map;
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/* Flags to the open system call. */
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CB_TARGET_DEFS_MAP *open_map;
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/* Signal numbers. */
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CB_TARGET_DEFS_MAP *signal_map;
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/* Layout of `stat' struct.
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The format is a series of "name,length" pairs separated by colons.
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Empty space is indicated with a `name' of "space".
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All padding must be explicitly mentioned.
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Lengths are in bytes. If this needs to be extended to bits,
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use "name.bits".
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Example: "st_dev,4:st_ino,4:st_mode,4:..." */
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const char *stat_map;
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enum bfd_endian target_endian;
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/* Size of an "int" on the target (for syscalls whose ABI uses "int").
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This must include padding, and only padding-at-higher-address is
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supported. For example, a 64-bit target with 32-bit int:s which
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are padded to 64 bits when in an array, should supposedly set this
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to 8. The default is 4 which matches ILP32 targets and 64-bit
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targets with 32-bit ints and no padding. */
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int target_sizeof_int;
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/* Marker for those wanting to do sanity checks.
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This should remain the last member of this struct to help catch
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miscompilation errors. */
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#define HOST_CALLBACK_MAGIC 4705 /* teds constant */
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int magic;
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};
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extern host_callback default_callback;
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/* Canonical versions of system call numbers.
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It's not intended to willy-nilly throw every system call ever heard
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of in here. Only include those that have an important use.
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??? One can certainly start a discussion over the ones that are currently
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here, but that will always be true. */
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/* These are used by the ANSI C support of libc. */
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#define CB_SYS_exit 1
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#define CB_SYS_open 2
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#define CB_SYS_close 3
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#define CB_SYS_read 4
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#define CB_SYS_write 5
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#define CB_SYS_lseek 6
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#define CB_SYS_unlink 7
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#define CB_SYS_getpid 8
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#define CB_SYS_kill 9
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#define CB_SYS_fstat 10
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/*#define CB_SYS_sbrk 11 - not currently a system call, but reserved. */
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/* ARGV support. */
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#define CB_SYS_argvlen 12
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#define CB_SYS_argv 13
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/* These are extras added for one reason or another. */
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#define CB_SYS_chdir 14
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#define CB_SYS_stat 15
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#define CB_SYS_chmod 16
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#define CB_SYS_utime 17
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#define CB_SYS_time 18
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/* More standard syscalls. */
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#define CB_SYS_lstat 19
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#define CB_SYS_rename 20
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#define CB_SYS_truncate 21
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#define CB_SYS_ftruncate 22
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#define CB_SYS_pipe 23
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/* Struct use to pass and return information necessary to perform a
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system call. */
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/* FIXME: Need to consider target word size. */
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typedef struct cb_syscall {
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/* The target's value of what system call to perform. */
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int func;
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/* The arguments to the syscall. */
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long arg1, arg2, arg3, arg4;
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/* The result. */
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long result;
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/* Some system calls have two results. */
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long result2;
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/* The target's errno value, or 0 if success.
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This is converted to the target's value with host_to_target_errno. */
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int errcode;
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/* Working space to be used by memory read/write callbacks. */
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PTR p1;
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PTR p2;
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long x1,x2;
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/* Callbacks for reading/writing memory (e.g. for read/write syscalls).
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??? long or unsigned long might be better to use for the `count'
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argument here. We mimic sim_{read,write} for now. Be careful to
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test any changes with -Wall -Werror, mixed signed comparisons
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will get you. */
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int (*read_mem) (host_callback * /*cb*/, struct cb_syscall * /*sc*/,
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unsigned long /*taddr*/, char * /*buf*/,
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int /*bytes*/);
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int (*write_mem) (host_callback * /*cb*/, struct cb_syscall * /*sc*/,
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unsigned long /*taddr*/, const char * /*buf*/,
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int /*bytes*/);
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/* For sanity checking, should be last entry. */
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int magic;
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} CB_SYSCALL;
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/* Magic number sanity checker. */
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#define CB_SYSCALL_MAGIC 0x12344321
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/* Macro to initialize CB_SYSCALL. Called first, before filling in
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any fields. */
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#define CB_SYSCALL_INIT(sc) \
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do { \
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memset ((sc), 0, sizeof (*(sc))); \
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(sc)->magic = CB_SYSCALL_MAGIC; \
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} while (0)
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/* Return codes for various interface routines. */
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typedef enum {
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CB_RC_OK = 0,
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/* generic error */
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CB_RC_ERR,
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/* either file not found or no read access */
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CB_RC_ACCESS,
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CB_RC_NO_MEM
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} CB_RC;
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/* Read in target values for system call numbers, errno values, signals. */
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CB_RC cb_read_target_syscall_maps (host_callback *, const char *);
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/* Translate target to host syscall function numbers. */
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int cb_target_to_host_syscall (host_callback *, int);
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/* Translate host to target errno value. */
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int cb_host_to_target_errno (host_callback *, int);
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/* Translate target to host open flags. */
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int cb_target_to_host_open (host_callback *, int);
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/* Translate target signal number to host. */
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int cb_target_to_host_signal (host_callback *, int);
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/* Translate host signal number to target. */
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int cb_host_to_target_signal (host_callback *, int);
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/* Translate host stat struct to target.
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If stat struct ptr is NULL, just compute target stat struct size.
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Result is size of target stat struct or 0 if error. */
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int cb_host_to_target_stat (host_callback *, const struct stat *, PTR);
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/* Translate a value to target endian. */
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void cb_store_target_endian (host_callback *, char *, int, long);
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/* Tests for special fds. */
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int cb_is_stdin (host_callback *, int);
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int cb_is_stdout (host_callback *, int);
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int cb_is_stderr (host_callback *, int);
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/* Perform a system call. */
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CB_RC cb_syscall (host_callback *, CB_SYSCALL *);
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#endif
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