1 /* Remote target system call callback support. 2 Copyright 1997 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 2 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, write to the Free Software 19 Foundation, 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 #ifdef ANSI_PROTOTYPES 54 #include <stdarg.h> 55 #else 56 #include <varargs.h> 57 #endif 58 #endif 59 /* Needed for enum bfd_endian. */ 60 #include "bfd.h" 61 62 /* Mapping of host/target values. */ 63 /* ??? For debugging purposes, one might want to add a string of the 64 name of the symbol. */ 65 66 typedef struct { 67 int host_val; 68 int target_val; 69 } CB_TARGET_DEFS_MAP; 70 71 #define MAX_CALLBACK_FDS 10 72 73 /* Forward decl for stat/fstat. */ 74 struct stat; 75 76 typedef struct host_callback_struct host_callback; 77 78 struct host_callback_struct 79 { 80 int (*close) PARAMS ((host_callback *,int)); 81 int (*get_errno) PARAMS ((host_callback *)); 82 int (*isatty) PARAMS ((host_callback *, int)); 83 int (*lseek) PARAMS ((host_callback *, int, long , int)); 84 int (*open) PARAMS ((host_callback *, const char*, int mode)); 85 int (*read) PARAMS ((host_callback *,int, char *, int)); 86 int (*read_stdin) PARAMS (( host_callback *, char *, int)); 87 int (*rename) PARAMS ((host_callback *, const char *, const char *)); 88 int (*system) PARAMS ((host_callback *, const char *)); 89 long (*time) PARAMS ((host_callback *, long *)); 90 int (*unlink) PARAMS ((host_callback *, const char *)); 91 int (*write) PARAMS ((host_callback *,int, const char *, int)); 92 int (*write_stdout) PARAMS ((host_callback *, const char *, int)); 93 void (*flush_stdout) PARAMS ((host_callback *)); 94 int (*write_stderr) PARAMS ((host_callback *, const char *, int)); 95 void (*flush_stderr) PARAMS ((host_callback *)); 96 int (*stat) PARAMS ((host_callback *, const char *, struct stat *)); 97 int (*fstat) PARAMS ((host_callback *, int, struct stat *)); 98 int (*lstat) PARAMS ((host_callback *, const char *, struct stat *)); 99 int (*ftruncate) PARAMS ((host_callback *, int, long)); 100 int (*truncate) PARAMS ((host_callback *, const char *, long)); 101 int (*pipe) PARAMS ((host_callback *, int *)); 102 103 /* Called by the framework when a read call has emptied a pipe buffer. */ 104 void (*pipe_empty) PARAMS ((host_callback *, int read_fd, int write_fd)); 105 106 /* Called by the framework when a write call makes a pipe buffer 107 non-empty. */ 108 void (*pipe_nonempty) PARAMS ((host_callback *, int read_fd, int write_fd)); 109 110 /* When present, call to the client to give it the oportunity to 111 poll any io devices for a request to quit (indicated by a nonzero 112 return value). */ 113 int (*poll_quit) PARAMS ((host_callback *)); 114 115 /* Used when the target has gone away, so we can close open 116 handles and free memory etc etc. */ 117 int (*shutdown) PARAMS ((host_callback *)); 118 int (*init) PARAMS ((host_callback *)); 119 120 /* depreciated, use vprintf_filtered - Talk to the user on a console. */ 121 void (*printf_filtered) PARAMS ((host_callback *, const char *, ...)); 122 123 /* Talk to the user on a console. */ 124 void (*vprintf_filtered) PARAMS ((host_callback *, const char *, va_list)); 125 126 /* Same as vprintf_filtered but to stderr. */ 127 void (*evprintf_filtered) PARAMS ((host_callback *, const char *, va_list)); 128 129 /* Print an error message and "exit". 130 In the case of gdb "exiting" means doing a longjmp back to the main 131 command loop. */ 132 void (*error) PARAMS ((host_callback *, const char *, ...)); 133 134 int last_errno; /* host format */ 135 136 int fdmap[MAX_CALLBACK_FDS]; 137 /* fd_buddy is used to contruct circular lists of target fds that point to 138 the same host fd. A uniquely mapped fd points to itself; for a closed 139 one, fd_buddy has the value -1. The host file descriptors for stdin / 140 stdout / stderr are never closed by the simulators, so they are put 141 in a special fd_buddy circular list which also has MAX_CALLBACK_FDS 142 as a member. */ 143 /* ??? We don't have a callback entry for dup, although it is trival to 144 implement now. */ 145 short fd_buddy[MAX_CALLBACK_FDS+1]; 146 147 /* 0 = none, >0 = reader (index of writer), 148 <0 = writer (negative index of reader). 149 If abs (ispipe[N]) == N, then N is an end of a pipe whose other 150 end is closed. */ 151 short ispipe[MAX_CALLBACK_FDS]; 152 153 /* A writer stores the buffer at its index. Consecutive writes 154 realloc the buffer and add to the size. The reader indicates the 155 read part in its .size, until it has consumed it all, at which 156 point it deallocates the buffer and zeroes out both sizes. */ 157 struct pipe_write_buffer 158 { 159 int size; 160 char *buffer; 161 } pipe_buffer[MAX_CALLBACK_FDS]; 162 163 /* System call numbers. */ 164 CB_TARGET_DEFS_MAP *syscall_map; 165 /* Errno values. */ 166 CB_TARGET_DEFS_MAP *errno_map; 167 /* Flags to the open system call. */ 168 CB_TARGET_DEFS_MAP *open_map; 169 /* Signal numbers. */ 170 CB_TARGET_DEFS_MAP *signal_map; 171 /* Layout of `stat' struct. 172 The format is a series of "name,length" pairs separated by colons. 173 Empty space is indicated with a `name' of "space". 174 All padding must be explicitly mentioned. 175 Lengths are in bytes. If this needs to be extended to bits, 176 use "name.bits". 177 Example: "st_dev,4:st_ino,4:st_mode,4:..." */ 178 const char *stat_map; 179 180 enum bfd_endian target_endian; 181 182 /* Size of an "int" on the target (for syscalls whose ABI uses "int"). 183 This must include padding, and only padding-at-higher-address is 184 supported. For example, a 64-bit target with 32-bit int:s which 185 are padded to 64 bits when in an array, should supposedly set this 186 to 8. The default is 4 which matches ILP32 targets and 64-bit 187 targets with 32-bit ints and no padding. */ 188 int target_sizeof_int; 189 190 /* Marker for those wanting to do sanity checks. 191 This should remain the last member of this struct to help catch 192 miscompilation errors. */ 193 #define HOST_CALLBACK_MAGIC 4705 /* teds constant */ 194 int magic; 195 }; 196 197 extern host_callback default_callback; 198 199 /* Canonical versions of system call numbers. 200 It's not intended to willy-nilly throw every system call ever heard 201 of in here. Only include those that have an important use. 202 ??? One can certainly start a discussion over the ones that are currently 203 here, but that will always be true. */ 204 205 /* These are used by the ANSI C support of libc. */ 206 #define CB_SYS_exit 1 207 #define CB_SYS_open 2 208 #define CB_SYS_close 3 209 #define CB_SYS_read 4 210 #define CB_SYS_write 5 211 #define CB_SYS_lseek 6 212 #define CB_SYS_unlink 7 213 #define CB_SYS_getpid 8 214 #define CB_SYS_kill 9 215 #define CB_SYS_fstat 10 216 /*#define CB_SYS_sbrk 11 - not currently a system call, but reserved. */ 217 218 /* ARGV support. */ 219 #define CB_SYS_argvlen 12 220 #define CB_SYS_argv 13 221 222 /* These are extras added for one reason or another. */ 223 #define CB_SYS_chdir 14 224 #define CB_SYS_stat 15 225 #define CB_SYS_chmod 16 226 #define CB_SYS_utime 17 227 #define CB_SYS_time 18 228 229 /* More standard syscalls. */ 230 #define CB_SYS_lstat 19 231 #define CB_SYS_rename 20 232 #define CB_SYS_truncate 21 233 #define CB_SYS_ftruncate 22 234 #define CB_SYS_pipe 23 235 236 /* Struct use to pass and return information necessary to perform a 237 system call. */ 238 /* FIXME: Need to consider target word size. */ 239 240 typedef struct cb_syscall { 241 /* The target's value of what system call to perform. */ 242 int func; 243 /* The arguments to the syscall. */ 244 long arg1, arg2, arg3, arg4; 245 246 /* The result. */ 247 long result; 248 /* Some system calls have two results. */ 249 long result2; 250 /* The target's errno value, or 0 if success. 251 This is converted to the target's value with host_to_target_errno. */ 252 int errcode; 253 254 /* Working space to be used by memory read/write callbacks. */ 255 PTR p1; 256 PTR p2; 257 long x1,x2; 258 259 /* Callbacks for reading/writing memory (e.g. for read/write syscalls). 260 ??? long or unsigned long might be better to use for the `count' 261 argument here. We mimic sim_{read,write} for now. Be careful to 262 test any changes with -Wall -Werror, mixed signed comparisons 263 will get you. */ 264 int (*read_mem) PARAMS ((host_callback * /*cb*/, struct cb_syscall * /*sc*/, 265 unsigned long /*taddr*/, char * /*buf*/, 266 int /*bytes*/)); 267 int (*write_mem) PARAMS ((host_callback * /*cb*/, struct cb_syscall * /*sc*/, 268 unsigned long /*taddr*/, const char * /*buf*/, 269 int /*bytes*/)); 270 271 /* For sanity checking, should be last entry. */ 272 int magic; 273 } CB_SYSCALL; 274 275 /* Magic number sanity checker. */ 276 #define CB_SYSCALL_MAGIC 0x12344321 277 278 /* Macro to initialize CB_SYSCALL. Called first, before filling in 279 any fields. */ 280 #define CB_SYSCALL_INIT(sc) \ 281 do { \ 282 memset ((sc), 0, sizeof (*(sc))); \ 283 (sc)->magic = CB_SYSCALL_MAGIC; \ 284 } while (0) 285 286 /* Return codes for various interface routines. */ 287 288 typedef enum { 289 CB_RC_OK = 0, 290 /* generic error */ 291 CB_RC_ERR, 292 /* either file not found or no read access */ 293 CB_RC_ACCESS, 294 CB_RC_NO_MEM 295 } CB_RC; 296 297 /* Read in target values for system call numbers, errno values, signals. */ 298 CB_RC cb_read_target_syscall_maps PARAMS ((host_callback *, const char *)); 299 300 /* Translate target to host syscall function numbers. */ 301 int cb_target_to_host_syscall PARAMS ((host_callback *, int)); 302 303 /* Translate host to target errno value. */ 304 int cb_host_to_target_errno PARAMS ((host_callback *, int)); 305 306 /* Translate target to host open flags. */ 307 int cb_target_to_host_open PARAMS ((host_callback *, int)); 308 309 /* Translate target signal number to host. */ 310 int cb_target_to_host_signal PARAMS ((host_callback *, int)); 311 312 /* Translate host signal number to target. */ 313 int cb_host_to_target_signal PARAMS ((host_callback *, int)); 314 315 /* Translate host stat struct to target. 316 If stat struct ptr is NULL, just compute target stat struct size. 317 Result is size of target stat struct or 0 if error. */ 318 int cb_host_to_target_stat PARAMS ((host_callback *, const struct stat *, PTR)); 319 320 /* Translate a value to target endian. */ 321 void cb_store_target_endian PARAMS ((host_callback *, char *, int, long)); 322 323 /* Perform a system call. */ 324 CB_RC cb_syscall PARAMS ((host_callback *, CB_SYSCALL *)); 325 326 #endif 327