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/* Remote target system call callback support. |
Copyright 1997-2013 Free Software Foundation, Inc. |
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 |
it under the terms of the GNU General Public License as published by |
the Free Software Foundation; either version 3 of the License, or |
(at your option) any later version. |
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This program is distributed in the hope that it will be useful, |
but WITHOUT ANY WARRANTY; without even the implied warranty of |
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
GNU General Public License for more details. |
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You should have received a copy of the GNU General Public License |
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 |
of remote (hardware, simulator, whatever). As such, support for it |
(e.g. sim/common/callback.c) should *not* live in the simulator source |
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 |
directly perform the system call on behalf of the target program. |
This is the typical way of handling system calls for embedded targets. |
[Handling system calls for embedded targets isn't that much of an |
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 |
is ENVIRONMENT_USER. |
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2) Have a simulator emulate the hardware as much as possible. |
If the program running on the real hardware communicates with some sort |
of target manager, one would want to be able to run this program on the |
simulator as well. |
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This method of system call handling is done when STATE_ENVIRONMENT |
is ENVIRONMENT_OPERATING. |
*/ |
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#ifndef CALLBACK_H |
#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 |
#include <ansidecl.h> |
#include <stdarg.h> |
#endif |
/* Needed for enum bfd_endian. */ |
#include "bfd.h" |
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/* Mapping of host/target values. */ |
/* ??? For debugging purposes, one might want to add a string of the |
name of the symbol. */ |
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typedef struct { |
int host_val; |
int target_val; |
} CB_TARGET_DEFS_MAP; |
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#define MAX_CALLBACK_FDS 10 |
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/* Forward decl for stat/fstat. */ |
struct stat; |
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typedef struct host_callback_struct host_callback; |
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struct host_callback_struct |
{ |
int (*close) (host_callback *,int); |
int (*get_errno) (host_callback *); |
int (*isatty) (host_callback *, int); |
int (*lseek) (host_callback *, int, long , int); |
int (*open) (host_callback *, const char*, int mode); |
int (*read) (host_callback *,int, char *, int); |
int (*read_stdin) ( host_callback *, char *, int); |
int (*rename) (host_callback *, const char *, const char *); |
int (*system) (host_callback *, const char *); |
long (*time) (host_callback *, long *); |
int (*unlink) (host_callback *, const char *); |
int (*write) (host_callback *,int, const char *, int); |
int (*write_stdout) (host_callback *, const char *, int); |
void (*flush_stdout) (host_callback *); |
int (*write_stderr) (host_callback *, const char *, int); |
void (*flush_stderr) (host_callback *); |
int (*stat) (host_callback *, const char *, struct stat *); |
int (*fstat) (host_callback *, int, struct stat *); |
int (*lstat) (host_callback *, const char *, struct stat *); |
int (*ftruncate) (host_callback *, int, long); |
int (*truncate) (host_callback *, const char *, long); |
int (*pipe) (host_callback *, int *); |
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/* Called by the framework when a read call has emptied a pipe buffer. */ |
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 |
non-empty. */ |
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 |
poll any io devices for a request to quit (indicated by a nonzero |
return value). */ |
int (*poll_quit) (host_callback *); |
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/* Used when the target has gone away, so we can close open |
handles and free memory etc etc. */ |
int (*shutdown) (host_callback *); |
int (*init) (host_callback *); |
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/* depreciated, use vprintf_filtered - Talk to the user on a console. */ |
void (*printf_filtered) (host_callback *, const char *, ...); |
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/* Talk to the user on a console. */ |
void (*vprintf_filtered) (host_callback *, const char *, va_list); |
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/* Same as vprintf_filtered but to stderr. */ |
void (*evprintf_filtered) (host_callback *, const char *, va_list); |
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/* Print an error message and "exit". |
In the case of gdb "exiting" means doing a longjmp back to the main |
command loop. */ |
void (*error) (host_callback *, const char *, ...) |
#ifdef __GNUC__ |
__attribute__ ((__noreturn__)) |
#endif |
; |
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int last_errno; /* host format */ |
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int fdmap[MAX_CALLBACK_FDS]; |
/* fd_buddy is used to contruct circular lists of target fds that point to |
the same host fd. A uniquely mapped fd points to itself; for a closed |
one, fd_buddy has the value -1. The host file descriptors for stdin / |
stdout / stderr are never closed by the simulators, so they are put |
in a special fd_buddy circular list which also has MAX_CALLBACK_FDS |
as a member. */ |
/* ??? We don't have a callback entry for dup, although it is trival to |
implement now. */ |
short fd_buddy[MAX_CALLBACK_FDS+1]; |
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/* 0 = none, >0 = reader (index of writer), |
<0 = writer (negative index of reader). |
If abs (ispipe[N]) == N, then N is an end of a pipe whose other |
end is closed. */ |
short ispipe[MAX_CALLBACK_FDS]; |
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/* A writer stores the buffer at its index. Consecutive writes |
realloc the buffer and add to the size. The reader indicates the |
read part in its .size, until it has consumed it all, at which |
point it deallocates the buffer and zeroes out both sizes. */ |
struct pipe_write_buffer |
{ |
int size; |
char *buffer; |
} pipe_buffer[MAX_CALLBACK_FDS]; |
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/* System call numbers. */ |
CB_TARGET_DEFS_MAP *syscall_map; |
/* Errno values. */ |
CB_TARGET_DEFS_MAP *errno_map; |
/* Flags to the open system call. */ |
CB_TARGET_DEFS_MAP *open_map; |
/* Signal numbers. */ |
CB_TARGET_DEFS_MAP *signal_map; |
/* Layout of `stat' struct. |
The format is a series of "name,length" pairs separated by colons. |
Empty space is indicated with a `name' of "space". |
All padding must be explicitly mentioned. |
Lengths are in bytes. If this needs to be extended to bits, |
use "name.bits". |
Example: "st_dev,4:st_ino,4:st_mode,4:..." */ |
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"). |
This must include padding, and only padding-at-higher-address is |
supported. For example, a 64-bit target with 32-bit int:s which |
are padded to 64 bits when in an array, should supposedly set this |
to 8. The default is 4 which matches ILP32 targets and 64-bit |
targets with 32-bit ints and no padding. */ |
int target_sizeof_int; |
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/* Marker for those wanting to do sanity checks. |
This should remain the last member of this struct to help catch |
miscompilation errors. */ |
#define HOST_CALLBACK_MAGIC 4705 /* teds constant */ |
int magic; |
}; |
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extern host_callback default_callback; |
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/* Canonical versions of system call numbers. |
It's not intended to willy-nilly throw every system call ever heard |
of in here. Only include those that have an important use. |
??? One can certainly start a discussion over the ones that are currently |
here, but that will always be true. */ |
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/* These are used by the ANSI C support of libc. */ |
#define CB_SYS_exit 1 |
#define CB_SYS_open 2 |
#define CB_SYS_close 3 |
#define CB_SYS_read 4 |
#define CB_SYS_write 5 |
#define CB_SYS_lseek 6 |
#define CB_SYS_unlink 7 |
#define CB_SYS_getpid 8 |
#define CB_SYS_kill 9 |
#define CB_SYS_fstat 10 |
/*#define CB_SYS_sbrk 11 - not currently a system call, but reserved. */ |
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/* ARGV support. */ |
#define CB_SYS_argvlen 12 |
#define CB_SYS_argv 13 |
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/* These are extras added for one reason or another. */ |
#define CB_SYS_chdir 14 |
#define CB_SYS_stat 15 |
#define CB_SYS_chmod 16 |
#define CB_SYS_utime 17 |
#define CB_SYS_time 18 |
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/* More standard syscalls. */ |
#define CB_SYS_lstat 19 |
#define CB_SYS_rename 20 |
#define CB_SYS_truncate 21 |
#define CB_SYS_ftruncate 22 |
#define CB_SYS_pipe 23 |
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/* New ARGV support. */ |
#define CB_SYS_argc 24 |
#define CB_SYS_argnlen 25 |
#define CB_SYS_argn 26 |
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/* Struct use to pass and return information necessary to perform a |
system call. */ |
/* FIXME: Need to consider target word size. */ |
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typedef struct cb_syscall { |
/* The target's value of what system call to perform. */ |
int func; |
/* The arguments to the syscall. */ |
long arg1, arg2, arg3, arg4; |
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/* The result. */ |
long result; |
/* Some system calls have two results. */ |
long result2; |
/* The target's errno value, or 0 if success. |
This is converted to the target's value with host_to_target_errno. */ |
int errcode; |
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/* Working space to be used by memory read/write callbacks. */ |
PTR p1; |
PTR p2; |
long x1,x2; |
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/* Callbacks for reading/writing memory (e.g. for read/write syscalls). |
??? long or unsigned long might be better to use for the `count' |
argument here. We mimic sim_{read,write} for now. Be careful to |
test any changes with -Wall -Werror, mixed signed comparisons |
will get you. */ |
int (*read_mem) (host_callback * /*cb*/, struct cb_syscall * /*sc*/, |
unsigned long /*taddr*/, char * /*buf*/, |
int /*bytes*/); |
int (*write_mem) (host_callback * /*cb*/, struct cb_syscall * /*sc*/, |
unsigned long /*taddr*/, const char * /*buf*/, |
int /*bytes*/); |
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/* For sanity checking, should be last entry. */ |
int magic; |
} CB_SYSCALL; |
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/* Magic number sanity checker. */ |
#define CB_SYSCALL_MAGIC 0x12344321 |
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/* Macro to initialize CB_SYSCALL. Called first, before filling in |
any fields. */ |
#define CB_SYSCALL_INIT(sc) \ |
do { \ |
memset ((sc), 0, sizeof (*(sc))); \ |
(sc)->magic = CB_SYSCALL_MAGIC; \ |
} while (0) |
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/* Return codes for various interface routines. */ |
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typedef enum { |
CB_RC_OK = 0, |
/* generic error */ |
CB_RC_ERR, |
/* either file not found or no read access */ |
CB_RC_ACCESS, |
CB_RC_NO_MEM |
} CB_RC; |
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/* Read in target values for system call numbers, errno values, signals. */ |
CB_RC cb_read_target_syscall_maps (host_callback *, const char *); |
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/* Translate target to host syscall function numbers. */ |
int cb_target_to_host_syscall (host_callback *, int); |
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/* Translate host to target errno value. */ |
int cb_host_to_target_errno (host_callback *, int); |
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/* Translate target to host open flags. */ |
int cb_target_to_host_open (host_callback *, int); |
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/* Translate target signal number to host. */ |
int cb_target_to_host_signal (host_callback *, int); |
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/* Translate host signal number to target. */ |
int cb_host_to_gdb_signal (host_callback *, int); |
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/* Translate host stat struct to target. |
If stat struct ptr is NULL, just compute target stat struct size. |
Result is size of target stat struct or 0 if error. */ |
int cb_host_to_target_stat (host_callback *, const struct stat *, PTR); |
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/* Translate a value to target endian. */ |
void cb_store_target_endian (host_callback *, char *, int, long); |
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/* Tests for special fds. */ |
int cb_is_stdin (host_callback *, int); |
int cb_is_stdout (host_callback *, int); |
int cb_is_stderr (host_callback *, int); |
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/* Read a string out of the target. */ |
int cb_get_string (host_callback *, CB_SYSCALL *, char *, int, unsigned long); |
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/* Perform a system call. */ |
CB_RC cb_syscall (host_callback *, CB_SYSCALL *); |
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#endif |