1 /* Remote target system call callback support. 2 Copyright (C) 1997-2016 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. */ 59 /* ??? For debugging purposes, one might want to add a string of the 60 name of the symbol. */ 61 62 typedef struct { 63 const char *name; 64 int host_val; 65 int target_val; 66 } CB_TARGET_DEFS_MAP; 67 68 #define MAX_CALLBACK_FDS 10 69 70 /* Forward decl for stat/fstat. */ 71 struct stat; 72 73 typedef struct host_callback_struct host_callback; 74 75 struct host_callback_struct 76 { 77 int (*close) (host_callback *,int); 78 int (*get_errno) (host_callback *); 79 int (*isatty) (host_callback *, int); 80 int (*lseek) (host_callback *, int, long , int); 81 int (*open) (host_callback *, const char*, int mode); 82 int (*read) (host_callback *,int, char *, int); 83 int (*read_stdin) ( host_callback *, char *, int); 84 int (*rename) (host_callback *, const char *, const char *); 85 int (*system) (host_callback *, const char *); 86 long (*time) (host_callback *, long *); 87 int (*unlink) (host_callback *, const char *); 88 int (*write) (host_callback *,int, const char *, int); 89 int (*write_stdout) (host_callback *, const char *, int); 90 void (*flush_stdout) (host_callback *); 91 int (*write_stderr) (host_callback *, const char *, int); 92 void (*flush_stderr) (host_callback *); 93 int (*to_stat) (host_callback *, const char *, struct stat *); 94 int (*to_fstat) (host_callback *, int, struct stat *); 95 int (*to_lstat) (host_callback *, const char *, struct stat *); 96 int (*ftruncate) (host_callback *, int, long); 97 int (*truncate) (host_callback *, const char *, long); 98 int (*pipe) (host_callback *, int *); 99 100 /* Called by the framework when a read call has emptied a pipe buffer. */ 101 void (*pipe_empty) (host_callback *, int read_fd, int write_fd); 102 103 /* Called by the framework when a write call makes a pipe buffer 104 non-empty. */ 105 void (*pipe_nonempty) (host_callback *, int read_fd, int write_fd); 106 107 /* When present, call to the client to give it the oportunity to 108 poll any io devices for a request to quit (indicated by a nonzero 109 return value). */ 110 int (*poll_quit) (host_callback *); 111 112 /* Used when the target has gone away, so we can close open 113 handles and free memory etc etc. */ 114 int (*shutdown) (host_callback *); 115 int (*init) (host_callback *); 116 117 /* depreciated, use vprintf_filtered - Talk to the user on a console. */ 118 void (*printf_filtered) (host_callback *, const char *, ...); 119 120 /* Talk to the user on a console. */ 121 void (*vprintf_filtered) (host_callback *, const char *, va_list); 122 123 /* Same as vprintf_filtered but to stderr. */ 124 void (*evprintf_filtered) (host_callback *, const char *, va_list); 125 126 /* Print an error message and "exit". 127 In the case of gdb "exiting" means doing a longjmp back to the main 128 command loop. */ 129 void (*error) (host_callback *, const char *, ...) 130 #ifdef __GNUC__ 131 __attribute__ ((__noreturn__)) 132 #endif 133 ; 134 135 int last_errno; /* host format */ 136 137 int fdmap[MAX_CALLBACK_FDS]; 138 /* fd_buddy is used to contruct circular lists of target fds that point to 139 the same host fd. A uniquely mapped fd points to itself; for a closed 140 one, fd_buddy has the value -1. The host file descriptors for stdin / 141 stdout / stderr are never closed by the simulators, so they are put 142 in a special fd_buddy circular list which also has MAX_CALLBACK_FDS 143 as a member. */ 144 /* ??? We don't have a callback entry for dup, although it is trival to 145 implement now. */ 146 short fd_buddy[MAX_CALLBACK_FDS+1]; 147 148 /* 0 = none, >0 = reader (index of writer), 149 <0 = writer (negative index of reader). 150 If abs (ispipe[N]) == N, then N is an end of a pipe whose other 151 end is closed. */ 152 short ispipe[MAX_CALLBACK_FDS]; 153 154 /* A writer stores the buffer at its index. Consecutive writes 155 realloc the buffer and add to the size. The reader indicates the 156 read part in its .size, until it has consumed it all, at which 157 point it deallocates the buffer and zeroes out both sizes. */ 158 struct pipe_write_buffer 159 { 160 int size; 161 char *buffer; 162 } pipe_buffer[MAX_CALLBACK_FDS]; 163 164 /* System call numbers. */ 165 CB_TARGET_DEFS_MAP *syscall_map; 166 /* Errno values. */ 167 CB_TARGET_DEFS_MAP *errno_map; 168 /* Flags to the open system call. */ 169 CB_TARGET_DEFS_MAP *open_map; 170 /* Signal numbers. */ 171 CB_TARGET_DEFS_MAP *signal_map; 172 /* Layout of `stat' struct. 173 The format is a series of "name,length" pairs separated by colons. 174 Empty space is indicated with a `name' of "space". 175 All padding must be explicitly mentioned. 176 Lengths are in bytes. If this needs to be extended to bits, 177 use "name.bits". 178 Example: "st_dev,4:st_ino,4:st_mode,4:..." */ 179 const char *stat_map; 180 181 enum bfd_endian target_endian; 182 183 /* Size of an "int" on the target (for syscalls whose ABI uses "int"). 184 This must include padding, and only padding-at-higher-address is 185 supported. For example, a 64-bit target with 32-bit int:s which 186 are padded to 64 bits when in an array, should supposedly set this 187 to 8. The default is 4 which matches ILP32 targets and 64-bit 188 targets with 32-bit ints and no padding. */ 189 int target_sizeof_int; 190 191 /* Marker for those wanting to do sanity checks. 192 This should remain the last member of this struct to help catch 193 miscompilation errors. */ 194 #define HOST_CALLBACK_MAGIC 4705 /* teds constant */ 195 int magic; 196 }; 197 198 extern host_callback default_callback; 199 200 /* Canonical versions of system call numbers. 202 It's not intended to willy-nilly throw every system call ever heard 203 of in here. Only include those that have an important use. 204 ??? One can certainly start a discussion over the ones that are currently 205 here, but that will always be true. */ 206 207 /* These are used by the ANSI C support of libc. */ 208 #define CB_SYS_exit 1 209 #define CB_SYS_open 2 210 #define CB_SYS_close 3 211 #define CB_SYS_read 4 212 #define CB_SYS_write 5 213 #define CB_SYS_lseek 6 214 #define CB_SYS_unlink 7 215 #define CB_SYS_getpid 8 216 #define CB_SYS_kill 9 217 #define CB_SYS_fstat 10 218 /*#define CB_SYS_sbrk 11 - not currently a system call, but reserved. */ 219 220 /* ARGV support. */ 221 #define CB_SYS_argvlen 12 222 #define CB_SYS_argv 13 223 224 /* These are extras added for one reason or another. */ 225 #define CB_SYS_chdir 14 226 #define CB_SYS_stat 15 227 #define CB_SYS_chmod 16 228 #define CB_SYS_utime 17 229 #define CB_SYS_time 18 230 231 /* More standard syscalls. */ 232 #define CB_SYS_lstat 19 233 #define CB_SYS_rename 20 234 #define CB_SYS_truncate 21 235 #define CB_SYS_ftruncate 22 236 #define CB_SYS_pipe 23 237 238 /* New ARGV support. */ 239 #define CB_SYS_argc 24 240 #define CB_SYS_argnlen 25 241 #define CB_SYS_argn 26 242 243 /* Struct use to pass and return information necessary to perform a 245 system call. */ 246 /* FIXME: Need to consider target word size. */ 247 248 typedef struct cb_syscall { 249 /* The target's value of what system call to perform. */ 250 int func; 251 /* The arguments to the syscall. */ 252 long arg1, arg2, arg3, arg4; 253 254 /* The result. */ 255 long result; 256 /* Some system calls have two results. */ 257 long result2; 258 /* The target's errno value, or 0 if success. 259 This is converted to the target's value with host_to_target_errno. */ 260 int errcode; 261 262 /* Working space to be used by memory read/write callbacks. */ 263 PTR p1; 264 PTR p2; 265 long x1,x2; 266 267 /* Callbacks for reading/writing memory (e.g. for read/write syscalls). 268 ??? long or unsigned long might be better to use for the `count' 269 argument here. We mimic sim_{read,write} for now. Be careful to 270 test any changes with -Wall -Werror, mixed signed comparisons 271 will get you. */ 272 int (*read_mem) (host_callback * /*cb*/, struct cb_syscall * /*sc*/, 273 unsigned long /*taddr*/, char * /*buf*/, 274 int /*bytes*/); 275 int (*write_mem) (host_callback * /*cb*/, struct cb_syscall * /*sc*/, 276 unsigned long /*taddr*/, const char * /*buf*/, 277 int /*bytes*/); 278 279 /* For sanity checking, should be last entry. */ 280 int magic; 281 } CB_SYSCALL; 282 283 /* Magic number sanity checker. */ 284 #define CB_SYSCALL_MAGIC 0x12344321 285 286 /* Macro to initialize CB_SYSCALL. Called first, before filling in 287 any fields. */ 288 #define CB_SYSCALL_INIT(sc) \ 289 do { \ 290 memset ((sc), 0, sizeof (*(sc))); \ 291 (sc)->magic = CB_SYSCALL_MAGIC; \ 292 } while (0) 293 294 /* Return codes for various interface routines. */ 296 297 typedef enum { 298 CB_RC_OK = 0, 299 /* generic error */ 300 CB_RC_ERR, 301 /* either file not found or no read access */ 302 CB_RC_ACCESS, 303 CB_RC_NO_MEM 304 } CB_RC; 305 306 /* Read in target values for system call numbers, errno values, signals. */ 307 CB_RC cb_read_target_syscall_maps (host_callback *, const char *); 308 309 /* Translate target to host syscall function numbers. */ 310 int cb_target_to_host_syscall (host_callback *, int); 311 312 /* Translate host to target errno value. */ 313 int cb_host_to_target_errno (host_callback *, int); 314 315 /* Translate target to host open flags. */ 316 int cb_target_to_host_open (host_callback *, int); 317 318 /* Translate target signal number to host. */ 319 int cb_target_to_host_signal (host_callback *, int); 320 321 /* Translate host signal number to target. */ 322 int cb_host_to_gdb_signal (host_callback *, int); 323 324 /* Translate symbols into human readable strings. */ 325 const char *cb_host_str_syscall (host_callback *, int); 326 const char *cb_host_str_errno (host_callback *, int); 327 const char *cb_host_str_signal (host_callback *, int); 328 const char *cb_target_str_syscall (host_callback *, int); 329 const char *cb_target_str_errno (host_callback *, int); 330 const char *cb_target_str_signal (host_callback *, int); 331 332 /* Translate host stat struct to target. 333 If stat struct ptr is NULL, just compute target stat struct size. 334 Result is size of target stat struct or 0 if error. */ 335 int cb_host_to_target_stat (host_callback *, const struct stat *, PTR); 336 337 /* Translate a value to target endian. */ 338 void cb_store_target_endian (host_callback *, char *, int, long); 339 340 /* Tests for special fds. */ 341 int cb_is_stdin (host_callback *, int); 342 int cb_is_stdout (host_callback *, int); 343 int cb_is_stderr (host_callback *, int); 344 345 /* Read a string out of the target. */ 346 int cb_get_string (host_callback *, CB_SYSCALL *, char *, int, unsigned long); 347 348 /* Perform a system call. */ 349 CB_RC cb_syscall (host_callback *, CB_SYSCALL *); 350 351 #endif 352
