1 /* Remote target system call callback support. 2 Copyright (C) 1997-2024 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 SIM_CALLBACK_H 46 #define SIM_CALLBACK_H 47 48 #include <stdarg.h> 49 #include <stdint.h> 50 51 #include <ansidecl.h> 52 /* Needed for enum bfd_endian. */ 53 #include <bfd.h> 54 55 /* Mapping of host/target values. */ 56 /* ??? For debugging purposes, one might want to add a string of the 57 name of the symbol. */ 58 59 typedef struct { 60 const char *name; 61 int host_val; 62 int target_val; 63 } CB_TARGET_DEFS_MAP; 64 65 #define MAX_CALLBACK_FDS 10 66 67 /* Forward decl for stat/fstat. */ 68 struct stat; 69 70 typedef struct host_callback_struct host_callback; 71 72 struct host_callback_struct 73 { 74 int (*close) (host_callback *,int); 75 int (*get_errno) (host_callback *); 76 int (*isatty) (host_callback *, int); 77 int64_t (*lseek) (host_callback *, int, int64_t, int); 78 int (*open) (host_callback *, const char*, int mode); 79 int (*read) (host_callback *,int, char *, int); 80 int (*read_stdin) ( host_callback *, char *, int); 81 int (*rename) (host_callback *, const char *, const char *); 82 int (*system) (host_callback *, const char *); 83 int64_t (*time) (host_callback *); 84 int (*unlink) (host_callback *, const char *); 85 int (*write) (host_callback *,int, const char *, int); 86 int (*write_stdout) (host_callback *, const char *, int); 87 void (*flush_stdout) (host_callback *); 88 int (*write_stderr) (host_callback *, const char *, int); 89 void (*flush_stderr) (host_callback *); 90 int (*to_stat) (host_callback *, const char *, struct stat *); 91 int (*to_fstat) (host_callback *, int, struct stat *); 92 int (*to_lstat) (host_callback *, const char *, struct stat *); 93 int (*ftruncate) (host_callback *, int, int64_t); 94 int (*truncate) (host_callback *, const char *, int64_t); 95 int (*getpid) (host_callback *); 96 int (*kill) (host_callback *, int, int); 97 int (*pipe) (host_callback *, int *); 98 99 /* Called by the framework when a read call has emptied a pipe buffer. */ 100 void (*pipe_empty) (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) (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) (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) (host_callback *); 114 int (*init) (host_callback *); 115 116 /* depreciated, use vprintf_filtered - Talk to the user on a console. */ 117 void (*printf_filtered) (host_callback *, const char *, ...) 118 ATTRIBUTE_PRINTF_2; 119 120 /* Talk to the user on a console. */ 121 void (*vprintf_filtered) (host_callback *, const char *, va_list) 122 ATTRIBUTE_PRINTF (2, 0); 123 124 /* Same as vprintf_filtered but to stderr. */ 125 void (*evprintf_filtered) (host_callback *, const char *, va_list) 126 ATTRIBUTE_PRINTF (2, 0); 127 128 /* Print an error message and "exit". 129 In the case of gdb "exiting" means doing a longjmp back to the main 130 command loop. */ 131 void (*error) (host_callback *, const char *, ...) 132 ATTRIBUTE_NORETURN ATTRIBUTE_PRINTF_2; 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 /* Program command line options. */ 183 char **argv; 184 185 /* Program environment. */ 186 char **envp; 187 188 /* Size of an "int" on the target (for syscalls whose ABI uses "int"). 189 This must include padding, and only padding-at-higher-address is 190 supported. For example, a 64-bit target with 32-bit int:s which 191 are padded to 64 bits when in an array, should supposedly set this 192 to 8. The default is 4 which matches ILP32 targets and 64-bit 193 targets with 32-bit ints and no padding. */ 194 int target_sizeof_int; 195 196 /* Marker for those wanting to do sanity checks. 197 This should remain the last member of this struct to help catch 198 miscompilation errors. */ 199 #define HOST_CALLBACK_MAGIC 4705 /* teds constant */ 200 int magic; 201 }; 202 203 extern host_callback default_callback; 204 205 /* Canonical versions of system call numbers. 206 It's not intended to willy-nilly throw every system call ever heard 207 of in here. Only include those that have an important use. 208 ??? One can certainly start a discussion over the ones that are currently 209 here, but that will always be true. */ 210 211 /* These are used by the ANSI C support of libc. */ 212 #define CB_SYS_exit 1 213 #define CB_SYS_open 2 214 #define CB_SYS_close 3 215 #define CB_SYS_read 4 216 #define CB_SYS_write 5 217 #define CB_SYS_lseek 6 218 #define CB_SYS_unlink 7 219 #define CB_SYS_getpid 8 220 #define CB_SYS_kill 9 221 #define CB_SYS_fstat 10 222 /*#define CB_SYS_sbrk 11 - not currently a system call, but reserved. */ 223 224 /* ARGV support. */ 225 #define CB_SYS_argvlen 12 226 #define CB_SYS_argv 13 227 228 /* These are extras added for one reason or another. */ 229 #define CB_SYS_chdir 14 230 #define CB_SYS_stat 15 231 #define CB_SYS_chmod 16 232 #define CB_SYS_utime 17 233 #define CB_SYS_time 18 234 235 /* More standard syscalls. */ 236 #define CB_SYS_lstat 19 237 #define CB_SYS_rename 20 238 #define CB_SYS_truncate 21 239 #define CB_SYS_ftruncate 22 240 #define CB_SYS_pipe 23 241 242 /* New ARGV support. */ 243 #define CB_SYS_argc 24 244 #define CB_SYS_argnlen 25 245 #define CB_SYS_argn 26 246 247 /* Struct use to pass and return information necessary to perform a 248 system call. */ 249 /* FIXME: Need to consider target word size. */ 250 251 typedef struct cb_syscall { 252 /* The target's value of what system call to perform. */ 253 int func; 254 /* The arguments to the syscall. */ 255 long arg1, arg2, arg3, arg4, arg5, arg6, arg7; 256 257 /* The result. */ 258 long result; 259 /* Some system calls have two results. */ 260 long result2; 261 /* The target's errno value, or 0 if success. 262 This is converted to the target's value with host_to_target_errno. */ 263 int errcode; 264 265 /* Working space to be used by memory read/write callbacks. */ 266 void *p1; 267 void *p2; 268 long x1,x2; 269 270 /* Callbacks for reading/writing memory (e.g. for read/write syscalls). 271 ??? long or unsigned long might be better to use for the `count' 272 argument here. We mimic sim_{read,write} for now. Be careful to 273 test any changes with -Wall -Werror, mixed signed comparisons 274 will get you. */ 275 int (*read_mem) (host_callback * /*cb*/, struct cb_syscall * /*sc*/, 276 unsigned long /*taddr*/, char * /*buf*/, 277 int /*bytes*/); 278 int (*write_mem) (host_callback * /*cb*/, struct cb_syscall * /*sc*/, 279 unsigned long /*taddr*/, const char * /*buf*/, 280 int /*bytes*/); 281 282 /* For sanity checking, should be last entry. */ 283 int magic; 284 } CB_SYSCALL; 285 286 /* Magic number sanity checker. */ 287 #define CB_SYSCALL_MAGIC 0x12344321 288 289 /* Macro to initialize CB_SYSCALL. Called first, before filling in 290 any fields. */ 291 #define CB_SYSCALL_INIT(sc) \ 292 do { \ 293 memset ((sc), 0, sizeof (*(sc))); \ 294 (sc)->magic = CB_SYSCALL_MAGIC; \ 295 } while (0) 296 297 /* Return codes for various interface routines. */ 298 299 typedef enum { 300 CB_RC_OK = 0, 301 /* generic error */ 302 CB_RC_ERR, 303 /* either file not found or no read access */ 304 CB_RC_ACCESS, 305 CB_RC_NO_MEM 306 } CB_RC; 307 308 /* Read in target values for system call numbers, errno values, signals. */ 309 CB_RC cb_read_target_syscall_maps (host_callback *, const char *); 310 311 /* Translate target to host syscall function numbers. */ 312 int cb_target_to_host_syscall (host_callback *, int); 313 314 /* Translate host to target errno value. */ 315 int cb_host_to_target_errno (host_callback *, int); 316 317 /* Translate target to host open flags. */ 318 int cb_target_to_host_open (host_callback *, int); 319 320 /* Translate target signal number to host. */ 321 int cb_target_to_host_signal (host_callback *, int); 322 323 /* Translate host signal number to target. */ 324 int cb_host_to_gdb_signal (host_callback *, int); 325 326 /* Translate symbols into human readable strings. */ 327 const char *cb_host_str_syscall (host_callback *, int); 328 const char *cb_host_str_errno (host_callback *, int); 329 const char *cb_host_str_signal (host_callback *, int); 330 const char *cb_target_str_syscall (host_callback *, int); 331 const char *cb_target_str_errno (host_callback *, int); 332 const char *cb_target_str_signal (host_callback *, int); 333 334 /* Translate host stat struct to target. 335 If stat struct ptr is NULL, just compute target stat struct size. 336 Result is size of target stat struct or 0 if error. */ 337 int cb_host_to_target_stat (host_callback *, const struct stat *, void *); 338 339 /* Translate a value to target endian. */ 340 void cb_store_target_endian (host_callback *, char *, int, long); 341 342 /* Tests for special fds. */ 343 int cb_is_stdin (host_callback *, int); 344 int cb_is_stdout (host_callback *, int); 345 int cb_is_stderr (host_callback *, int); 346 347 /* Read a string out of the target. */ 348 int cb_get_string (host_callback *, CB_SYSCALL *, char *, int, unsigned long); 349 350 /* Perform a system call. */ 351 CB_RC cb_syscall (host_callback *, CB_SYSCALL *); 352 353 #endif 354