1/* Remote target system call callback support. 2 Copyright 1997, 2007 Free Software Foundation, Inc. 3 Contributed by Cygnus Solutions. 4 5This file is part of GDB. 6 7This program is free software; you can redistribute it and/or modify 8it under the terms of the GNU General Public License as published by 9the Free Software Foundation; either version 2 of the License, or 10(at your option) any later version. 11 12This program is distributed in the hope that it will be useful, 13but WITHOUT ANY WARRANTY; without even the implied warranty of 14MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15GNU General Public License for more details. 16 17You should have received a copy of the GNU General Public License 18along with this program; if not, write to the Free Software 19Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ 20 21/* This interface isn't intended to be specific to any particular kind 22 of remote (hardware, simulator, whatever). As such, support for it 23 (e.g. sim/common/callback.c) should *not* live in the simulator source 24 tree, nor should it live in the gdb source tree. */ 25 26/* There are various ways to handle system calls: 27 28 1) Have a simulator intercept the appropriate trap instruction and 29 directly perform the system call on behalf of the target program. 30 This is the typical way of handling system calls for embedded targets. 31 [Handling system calls for embedded targets isn't that much of an 32 oxymoron as running compiler testsuites make use of the capability.] 33 34 This method of system call handling is done when STATE_ENVIRONMENT 35 is ENVIRONMENT_USER. 36 37 2) Have a simulator emulate the hardware as much as possible. 38 If the program running on the real hardware communicates with some sort 39 of target manager, one would want to be able to run this program on the 40 simulator as well. 41 42 This method of system call handling is done when STATE_ENVIRONMENT 43 is ENVIRONMENT_OPERATING. 44*/ 45 46#ifndef CALLBACK_H 47#define CALLBACK_H 48 49/* ??? The reason why we check for va_start here should be documented. */ 50 51#ifndef va_start 52#include <ansidecl.h> 53#include <stdarg.h> 54#endif 55/* Needed for enum bfd_endian. */ 56#include "bfd.h" 57 58/* Mapping of host/target values. */ 59/* ??? For debugging purposes, one might want to add a string of the 60 name of the symbol. */ 61 62typedef struct { 63 int host_val; 64 int target_val; 65} CB_TARGET_DEFS_MAP; 66 67#define MAX_CALLBACK_FDS 10 68 69/* Forward decl for stat/fstat. */ 70struct stat; 71 72typedef struct host_callback_struct host_callback; 73 74struct host_callback_struct 75{ 76 int (*close) PARAMS ((host_callback *,int)); 77 int (*get_errno) PARAMS ((host_callback *)); 78 int (*isatty) PARAMS ((host_callback *, int)); 79 int (*lseek) PARAMS ((host_callback *, int, long , int)); 80 int (*open) PARAMS ((host_callback *, const char*, int mode)); 81 int (*read) PARAMS ((host_callback *,int, char *, int)); 82 int (*read_stdin) PARAMS (( host_callback *, char *, int)); 83 int (*rename) PARAMS ((host_callback *, const char *, const char *)); 84 int (*system) PARAMS ((host_callback *, const char *)); 85 long (*time) PARAMS ((host_callback *, long *)); 86 int (*unlink) PARAMS ((host_callback *, const char *)); 87 int (*write) PARAMS ((host_callback *,int, const char *, int)); 88 int (*write_stdout) PARAMS ((host_callback *, const char *, int)); 89 void (*flush_stdout) PARAMS ((host_callback *)); 90 int (*write_stderr) PARAMS ((host_callback *, const char *, int)); 91 void (*flush_stderr) PARAMS ((host_callback *)); 92 int (*stat) PARAMS ((host_callback *, const char *, struct stat *)); 93 int (*fstat) PARAMS ((host_callback *, int, struct stat *)); 94 int (*lstat) PARAMS ((host_callback *, const char *, struct stat *)); 95 int (*ftruncate) PARAMS ((host_callback *, int, long)); 96 int (*truncate) PARAMS ((host_callback *, const char *, long)); 97 int (*pipe) PARAMS ((host_callback *, int *)); 98 99 /* Called by the framework when a read call has emptied a pipe buffer. */ 100 void (*pipe_empty) PARAMS ((host_callback *, int read_fd, int write_fd)); 101 102 /* Called by the framework when a write call makes a pipe buffer 103 non-empty. */ 104 void (*pipe_nonempty) PARAMS ((host_callback *, int read_fd, int write_fd)); 105 106 /* When present, call to the client to give it the oportunity to 107 poll any io devices for a request to quit (indicated by a nonzero 108 return value). */ 109 int (*poll_quit) PARAMS ((host_callback *)); 110 111 /* Used when the target has gone away, so we can close open 112 handles and free memory etc etc. */ 113 int (*shutdown) PARAMS ((host_callback *)); 114 int (*init) PARAMS ((host_callback *)); 115 116 /* depreciated, use vprintf_filtered - Talk to the user on a console. */ 117 void (*printf_filtered) PARAMS ((host_callback *, const char *, ...)); 118 119 /* Talk to the user on a console. */ 120 void (*vprintf_filtered) PARAMS ((host_callback *, const char *, va_list)); 121 122 /* Same as vprintf_filtered but to stderr. */ 123 void (*evprintf_filtered) PARAMS ((host_callback *, const char *, va_list)); 124 125 /* Print an error message and "exit". 126 In the case of gdb "exiting" means doing a longjmp back to the main 127 command loop. */ 128 void (*error) PARAMS ((host_callback *, const char *, ...)); 129 130 int last_errno; /* host format */ 131 132 int fdmap[MAX_CALLBACK_FDS]; 133 /* fd_buddy is used to contruct circular lists of target fds that point to 134 the same host fd. A uniquely mapped fd points to itself; for a closed 135 one, fd_buddy has the value -1. The host file descriptors for stdin / 136 stdout / stderr are never closed by the simulators, so they are put 137 in a special fd_buddy circular list which also has MAX_CALLBACK_FDS 138 as a member. */ 139 /* ??? We don't have a callback entry for dup, although it is trival to 140 implement now. */ 141 short fd_buddy[MAX_CALLBACK_FDS+1]; 142 143 /* 0 = none, >0 = reader (index of writer), 144 <0 = writer (negative index of reader). 145 If abs (ispipe[N]) == N, then N is an end of a pipe whose other 146 end is closed. */ 147 short ispipe[MAX_CALLBACK_FDS]; 148 149 /* A writer stores the buffer at its index. Consecutive writes 150 realloc the buffer and add to the size. The reader indicates the 151 read part in its .size, until it has consumed it all, at which 152 point it deallocates the buffer and zeroes out both sizes. */ 153 struct pipe_write_buffer 154 { 155 int size; 156 char *buffer; 157 } pipe_buffer[MAX_CALLBACK_FDS]; 158 159 /* System call numbers. */ 160 CB_TARGET_DEFS_MAP *syscall_map; 161 /* Errno values. */ 162 CB_TARGET_DEFS_MAP *errno_map; 163 /* Flags to the open system call. */ 164 CB_TARGET_DEFS_MAP *open_map; 165 /* Signal numbers. */ 166 CB_TARGET_DEFS_MAP *signal_map; 167 /* Layout of `stat' struct. 168 The format is a series of "name,length" pairs separated by colons. 169 Empty space is indicated with a `name' of "space". 170 All padding must be explicitly mentioned. 171 Lengths are in bytes. If this needs to be extended to bits, 172 use "name.bits". 173 Example: "st_dev,4:st_ino,4:st_mode,4:..." */ 174 const char *stat_map; 175 176 enum bfd_endian target_endian; 177 178 /* Size of an "int" on the target (for syscalls whose ABI uses "int"). 179 This must include padding, and only padding-at-higher-address is 180 supported. For example, a 64-bit target with 32-bit int:s which 181 are padded to 64 bits when in an array, should supposedly set this 182 to 8. The default is 4 which matches ILP32 targets and 64-bit 183 targets with 32-bit ints and no padding. */ 184 int target_sizeof_int; 185 186 /* Marker for those wanting to do sanity checks. 187 This should remain the last member of this struct to help catch 188 miscompilation errors. */ 189#define HOST_CALLBACK_MAGIC 4705 /* teds constant */ 190 int magic; 191}; 192 193extern host_callback default_callback; 194 195/* Canonical versions of system call numbers. 196 It's not intended to willy-nilly throw every system call ever heard 197 of in here. Only include those that have an important use. 198 ??? One can certainly start a discussion over the ones that are currently 199 here, but that will always be true. */ 200 201/* These are used by the ANSI C support of libc. */ 202#define CB_SYS_exit 1 203#define CB_SYS_open 2 204#define CB_SYS_close 3 205#define CB_SYS_read 4 206#define CB_SYS_write 5 207#define CB_SYS_lseek 6 208#define CB_SYS_unlink 7 209#define CB_SYS_getpid 8 210#define CB_SYS_kill 9 211#define CB_SYS_fstat 10 212/*#define CB_SYS_sbrk 11 - not currently a system call, but reserved. */ 213 214/* ARGV support. */ 215#define CB_SYS_argvlen 12 216#define CB_SYS_argv 13 217 218/* These are extras added for one reason or another. */ 219#define CB_SYS_chdir 14 220#define CB_SYS_stat 15 221#define CB_SYS_chmod 16 222#define CB_SYS_utime 17 223#define CB_SYS_time 18 224 225/* More standard syscalls. */ 226#define CB_SYS_lstat 19 227#define CB_SYS_rename 20 228#define CB_SYS_truncate 21 229#define CB_SYS_ftruncate 22 230#define CB_SYS_pipe 23 231 232/* Struct use to pass and return information necessary to perform a 233 system call. */ 234/* FIXME: Need to consider target word size. */ 235 236typedef struct cb_syscall { 237 /* The target's value of what system call to perform. */ 238 int func; 239 /* The arguments to the syscall. */ 240 long arg1, arg2, arg3, arg4; 241 242 /* The result. */ 243 long result; 244 /* Some system calls have two results. */ 245 long result2; 246 /* The target's errno value, or 0 if success. 247 This is converted to the target's value with host_to_target_errno. */ 248 int errcode; 249 250 /* Working space to be used by memory read/write callbacks. */ 251 PTR p1; 252 PTR p2; 253 long x1,x2; 254 255 /* Callbacks for reading/writing memory (e.g. for read/write syscalls). 256 ??? long or unsigned long might be better to use for the `count' 257 argument here. We mimic sim_{read,write} for now. Be careful to 258 test any changes with -Wall -Werror, mixed signed comparisons 259 will get you. */ 260 int (*read_mem) PARAMS ((host_callback * /*cb*/, struct cb_syscall * /*sc*/, 261 unsigned long /*taddr*/, char * /*buf*/, 262 int /*bytes*/)); 263 int (*write_mem) PARAMS ((host_callback * /*cb*/, struct cb_syscall * /*sc*/, 264 unsigned long /*taddr*/, const char * /*buf*/, 265 int /*bytes*/)); 266 267 /* For sanity checking, should be last entry. */ 268 int magic; 269} CB_SYSCALL; 270 271/* Magic number sanity checker. */ 272#define CB_SYSCALL_MAGIC 0x12344321 273 274/* Macro to initialize CB_SYSCALL. Called first, before filling in 275 any fields. */ 276#define CB_SYSCALL_INIT(sc) \ 277do { \ 278 memset ((sc), 0, sizeof (*(sc))); \ 279 (sc)->magic = CB_SYSCALL_MAGIC; \ 280} while (0) 281 282/* Return codes for various interface routines. */ 283 284typedef enum { 285 CB_RC_OK = 0, 286 /* generic error */ 287 CB_RC_ERR, 288 /* either file not found or no read access */ 289 CB_RC_ACCESS, 290 CB_RC_NO_MEM 291} CB_RC; 292 293/* Read in target values for system call numbers, errno values, signals. */ 294CB_RC cb_read_target_syscall_maps PARAMS ((host_callback *, const char *)); 295 296/* Translate target to host syscall function numbers. */ 297int cb_target_to_host_syscall PARAMS ((host_callback *, int)); 298 299/* Translate host to target errno value. */ 300int cb_host_to_target_errno PARAMS ((host_callback *, int)); 301 302/* Translate target to host open flags. */ 303int cb_target_to_host_open PARAMS ((host_callback *, int)); 304 305/* Translate target signal number to host. */ 306int cb_target_to_host_signal PARAMS ((host_callback *, int)); 307 308/* Translate host signal number to target. */ 309int cb_host_to_target_signal PARAMS ((host_callback *, int)); 310 311/* Translate host stat struct to target. 312 If stat struct ptr is NULL, just compute target stat struct size. 313 Result is size of target stat struct or 0 if error. */ 314int cb_host_to_target_stat PARAMS ((host_callback *, const struct stat *, PTR)); 315 316/* Translate a value to target endian. */ 317void cb_store_target_endian PARAMS ((host_callback *, char *, int, long)); 318 319/* Perform a system call. */ 320CB_RC cb_syscall PARAMS ((host_callback *, CB_SYSCALL *)); 321 322#endif 323