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