| 1 | /* Target-dependent code for Interix running on i386's, for GDB. |
| 2 | Copyright 2002 Free Software Foundation, Inc. |
| 3 | |
| 4 | This file is part of GDB. |
| 5 | |
| 6 | This program is free software; you can redistribute it and/or modify |
| 7 | it under the terms of the GNU General Public License as published by |
| 8 | the Free Software Foundation; either version 2 of the License, or |
| 9 | (at your option) any later version. |
| 10 | |
| 11 | This program is distributed in the hope that it will be useful, |
| 12 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 14 | GNU General Public License for more details. |
| 15 | |
| 16 | You should have received a copy of the GNU General Public License |
| 17 | along with this program; if not, write to the Free Software |
| 18 | Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ |
| 19 | |
| 20 | #include "defs.h" |
| 21 | #include "arch-utils.h" |
| 22 | |
| 23 | #include "frame.h" |
| 24 | #include "gdb_string.h" |
| 25 | #include "gdb-stabs.h" |
| 26 | #include "gdbcore.h" |
| 27 | #include "gdbtypes.h" |
| 28 | #include "i386-tdep.h" |
| 29 | #include "inferior.h" |
| 30 | #include "libbfd.h" |
| 31 | #include "objfiles.h" |
| 32 | #include "osabi.h" |
| 33 | #include "regcache.h" |
| 34 | |
| 35 | /* offsetof (mcontext_t, gregs.gregs[EBP]) */ |
| 36 | static const int mcontext_EBP_greg_offset = 180; |
| 37 | |
| 38 | /* offsetof (mcontext_t, gregs.gregs[EIP]) */ |
| 39 | static const int mcontext_EIP_greg_offset = 184; |
| 40 | |
| 41 | /* offsetof (mcontext_t, gregs.gregs[UESP]) */ |
| 42 | static const int mcontext_UESP_greg_offset = 196; |
| 43 | |
| 44 | /* offsetof (mcontext_t, gregs.reserved[1]) */ |
| 45 | static const int mcontext_syscall_greg_offset = 4; |
| 46 | |
| 47 | /* offsetof (_JUMP_BUFFER, Eip) */ |
| 48 | static const int jump_buffer_Eip_offset = 20; |
| 49 | |
| 50 | /* See procfs.c and *interix*.h in config/[alpha,i386]. */ |
| 51 | /* ??? These should be static, but this needs a bit of work before this |
| 52 | can be done. */ |
| 53 | CORE_ADDR tramp_start; |
| 54 | CORE_ADDR tramp_end; |
| 55 | CORE_ADDR null_start; |
| 56 | CORE_ADDR null_end; |
| 57 | int winver; /* Windows NT version number */ |
| 58 | |
| 59 | /* Forward declarations. */ |
| 60 | extern void _initialize_i386_interix_tdep (void); |
| 61 | extern initialize_file_ftype _initialize_i386_interix_tdep; |
| 62 | |
| 63 | /* Adjust the section offsets in an objfile structure so that it's correct |
| 64 | for the type of symbols being read (or undo it with the _restore |
| 65 | arguments). |
| 66 | |
| 67 | If main programs ever start showing up at other than the default Image |
| 68 | Base, this is where that would likely be applied. */ |
| 69 | |
| 70 | void |
| 71 | pei_adjust_objfile_offsets (struct objfile *objfile, |
| 72 | enum objfile_adjusts type) |
| 73 | { |
| 74 | int i; |
| 75 | CORE_ADDR symbols_offset; |
| 76 | |
| 77 | switch (type) |
| 78 | { |
| 79 | case adjust_for_symtab: |
| 80 | symbols_offset = NONZERO_LINK_BASE (objfile->obfd); |
| 81 | break; |
| 82 | case adjust_for_symtab_restore: |
| 83 | symbols_offset = -NONZERO_LINK_BASE (objfile->obfd); |
| 84 | break; |
| 85 | case adjust_for_stabs: |
| 86 | case adjust_for_stabs_restore: |
| 87 | case adjust_for_dwarf: |
| 88 | case adjust_for_dwarf_restore: |
| 89 | default: |
| 90 | return; |
| 91 | } |
| 92 | |
| 93 | for (i = 0; i < objfile->num_sections; i++) |
| 94 | { |
| 95 | (objfile->section_offsets)->offsets[i] += symbols_offset; |
| 96 | } |
| 97 | } |
| 98 | |
| 99 | static int |
| 100 | i386_interix_pc_in_sigtramp (CORE_ADDR pc, char *name) |
| 101 | { |
| 102 | /* This is sufficient, where used, but is NOT a complete test; There |
| 103 | is more in DEPRECATED_INIT_EXTRA_FRAME_INFO |
| 104 | (a.k.a. interix_back_one_frame). */ |
| 105 | return ((pc >= tramp_start && pc < tramp_end) |
| 106 | || (pc >= null_start && pc < null_end)); |
| 107 | } |
| 108 | |
| 109 | static int |
| 110 | i386_interix_in_solib_call_trampoline (CORE_ADDR pc, char *name) |
| 111 | { |
| 112 | return i386_pe_skip_trampoline_code (pc, name); |
| 113 | } |
| 114 | |
| 115 | static CORE_ADDR |
| 116 | i386_interix_skip_trampoline_code (CORE_ADDR pc) |
| 117 | { |
| 118 | return i386_pe_skip_trampoline_code (pc, 0); |
| 119 | } |
| 120 | |
| 121 | static int |
| 122 | i386_interix_frame_chain_valid (CORE_ADDR chain, struct frame_info *thisframe) |
| 123 | { |
| 124 | /* In the context where this is used, we get the saved PC before we've |
| 125 | successfully unwound far enough to be sure what we've got (it may |
| 126 | be a signal handler caller). If we're dealing with a signal |
| 127 | handler caller, this will return valid, which is fine. If not, |
| 128 | it'll make the correct test. */ |
| 129 | return ((get_frame_type (thisframe) == SIGTRAMP_FRAME) |
| 130 | || (chain != 0 |
| 131 | && !deprecated_inside_entry_file (read_memory_integer |
| 132 | (thisframe->frame + 4, 4)))); |
| 133 | } |
| 134 | |
| 135 | /* We want to find the previous frame, which on Interix is tricky when |
| 136 | signals are involved; set frame->frame appropriately, and also get |
| 137 | the pc and tweak tye frame's type; this replaces a boatload of |
| 138 | nested macros, as well. */ |
| 139 | static void |
| 140 | i386_interix_back_one_frame (int fromleaf, struct frame_info *frame) |
| 141 | { |
| 142 | CORE_ADDR ra; |
| 143 | CORE_ADDR fm; |
| 144 | CORE_ADDR context; |
| 145 | long t; |
| 146 | |
| 147 | if (frame == NULL) |
| 148 | internal_error (__FILE__, __LINE__, "unexpected NULL frame"); |
| 149 | |
| 150 | if (fromleaf) |
| 151 | { |
| 152 | frame->pc = DEPRECATED_SAVED_PC_AFTER_CALL (frame->next); |
| 153 | return; |
| 154 | } |
| 155 | |
| 156 | if (!frame->next) |
| 157 | { |
| 158 | frame->pc = read_pc (); |
| 159 | |
| 160 | /* Part of the signal stuff... See below. */ |
| 161 | if (stopped_by_random_signal) |
| 162 | { |
| 163 | /* We know we're in a system call mini-frame; was it |
| 164 | NullApi or something else? */ |
| 165 | ra = DEPRECATED_SAVED_PC_AFTER_CALL (frame); |
| 166 | if (ra >= null_start && ra < null_end) |
| 167 | deprecated_set_frame_type (frame, SIGTRAMP_FRAME); |
| 168 | /* There might also be an indirect call to the mini-frame, |
| 169 | putting one more return address on the stack. (XP only, |
| 170 | I think?) This can't (reasonably) return the address of the |
| 171 | signal handler caller unless it's that situation, so this |
| 172 | is safe. */ |
| 173 | ra = read_memory_unsigned_integer (read_register (SP_REGNUM) + 4, 4); |
| 174 | if (ra >= null_start && ra < null_end) |
| 175 | deprecated_set_frame_type (frame, SIGTRAMP_FRAME); |
| 176 | } |
| 177 | return; |
| 178 | } |
| 179 | |
| 180 | if (!(get_frame_type (frame->next) == SIGTRAMP_FRAME)) |
| 181 | { |
| 182 | frame->pc = read_memory_integer (frame->next->frame + 4, 4); |
| 183 | return; |
| 184 | } |
| 185 | |
| 186 | /* This is messy (actually AWFUL)... The "trampoline" might be 2, 3 |
| 187 | or all 5 entities on the frame. |
| 188 | |
| 189 | Chunk 1 will be present when we're actually in a signal handler. |
| 190 | Chunk 2 will be present when an asynchronous signal (one that |
| 191 | didn't come in with a system call) is present. |
| 192 | We may not (yet) be in the handler, if we're just returning |
| 193 | from the call. |
| 194 | When we're actually in a handler taken from an asynchronous |
| 195 | signal, both will be present. |
| 196 | |
| 197 | Chunk 1: |
| 198 | PdxSignalDeliverer's frame |
| 199 | + Context struct -- not accounted for in any frame |
| 200 | |
| 201 | Chunk 2: |
| 202 | + PdxNullPosixApi's frame |
| 203 | + PdxNullApiCaller's frame |
| 204 | + Context struct = 0x230 not accounted for in any frame |
| 205 | |
| 206 | The symbol names come from examining objdumps of psxdll.dll; |
| 207 | they don't appear in the runtime image. |
| 208 | |
| 209 | For gdb's purposes, we can pile all this into one frame. */ |
| 210 | |
| 211 | ra = frame->next->pc; |
| 212 | /* Are we already pointing at PdxNullPosixApi? We are if |
| 213 | this is a signal frame, we're at next-to-top, and were stopped |
| 214 | by a random signal (if it wasn't the right address under |
| 215 | these circumstances, we wouldn't be here at all by tests above |
| 216 | on the prior frame). */ |
| 217 | if (frame->next->next == NULL && stopped_by_random_signal) |
| 218 | { |
| 219 | /* We're pointing at the frame FOR PdxNullApi. */ |
| 220 | fm = frame->frame; |
| 221 | } |
| 222 | else |
| 223 | { |
| 224 | /* No... We must be pointing at the frame that was called |
| 225 | by PdxSignalDeliverer; back up across the whole mess. */ |
| 226 | |
| 227 | /* Extract the frame for PdxSignalDeliverer. Note: |
| 228 | DEPRECATED_FRAME_CHAIN used the "old" frame pointer because |
| 229 | we were a deliverer. Get the address of the context record |
| 230 | that's on here frameless. */ |
| 231 | context = read_memory_integer (frame->frame, 4); /* an Arg */ |
| 232 | |
| 233 | /* Now extract the frame pointer contained in the context. */ |
| 234 | fm = read_memory_integer (context + mcontext_EBP_greg_offset, 4); |
| 235 | |
| 236 | ra = read_memory_integer (context + mcontext_EIP_greg_offset, 4); |
| 237 | |
| 238 | /* We need to know if we're in a system call because we'll be |
| 239 | in a syscall mini-frame, if so, and the rules are different. */ |
| 240 | t = (long) read_memory_integer (context + mcontext_syscall_greg_offset, |
| 241 | 4); |
| 242 | /* t contains 0 if running free, 1 if blocked on a system call, |
| 243 | and 2 if blocked on an exception message (e.g. a trap); |
| 244 | we don't expect to get here with a 2. */ |
| 245 | if (t != 1) |
| 246 | { |
| 247 | /* Not at a system call, therefore it can't be NullApi. */ |
| 248 | frame->pc = ra; |
| 249 | frame->frame = fm; |
| 250 | return; |
| 251 | } |
| 252 | |
| 253 | /* It's a system call... Mini frame, then look for NullApi. */ |
| 254 | /* Get the RA (on the stack) associated with this... It's |
| 255 | a system call mini-frame. */ |
| 256 | ra = read_memory_integer (context + mcontext_UESP_greg_offset, 4); |
| 257 | |
| 258 | if (winver >= 51) |
| 259 | { |
| 260 | /* Newer versions of Windows NT interpose another return |
| 261 | address (but no other "stack frame" stuff) that we need |
| 262 | to simply ignore here. */ |
| 263 | ra += 4; |
| 264 | } |
| 265 | |
| 266 | ra = read_memory_integer (ra, 4); |
| 267 | |
| 268 | if (!(ra >= null_start && ra < null_end)) |
| 269 | { |
| 270 | /* No Null API present; we're done. */ |
| 271 | frame->pc = ra; |
| 272 | frame->frame = fm; |
| 273 | return; |
| 274 | } |
| 275 | } |
| 276 | |
| 277 | /* At this point, we're looking at the frame for PdxNullPosixApi, |
| 278 | in either case. |
| 279 | |
| 280 | PdxNullPosixApi is called by PdxNullApiCaller (which in turn |
| 281 | is called by _PdxNullApiCaller (note the _).) |
| 282 | PdxNullPosixApiCaller (no _) is a frameless function. |
| 283 | |
| 284 | The saved frame pointer is as fm, but it's not of interest |
| 285 | to us because it skips us over the saved context, which is |
| 286 | the wrong thing to do, because it skips the interrrupted |
| 287 | routine! PdxNullApiCaller takes as its only argument the |
| 288 | address of the context of the interrupded function (which |
| 289 | is really in no frame, but jammed on the stack by the system) |
| 290 | |
| 291 | So: fm+0: saved bp |
| 292 | fm+4: return address to _PdxNullApiCaller |
| 293 | fm+8: arg to PdxNullApiCaller pushed by _Pdx... */ |
| 294 | |
| 295 | fm = read_memory_integer (fm + 0x8, 4); |
| 296 | |
| 297 | /* Extract the second context record. */ |
| 298 | |
| 299 | ra = read_memory_integer (fm + mcontext_EIP_greg_offset, 4); |
| 300 | fm = read_memory_integer (fm + mcontext_EBP_greg_offset, 4); |
| 301 | |
| 302 | frame->frame = fm; |
| 303 | frame->pc = ra; |
| 304 | |
| 305 | return; |
| 306 | } |
| 307 | |
| 308 | static CORE_ADDR |
| 309 | i386_interix_frame_saved_pc (struct frame_info *fi) |
| 310 | { |
| 311 | /* Assume that we've already unwound enough to have the caller's address |
| 312 | if we're dealing with a signal handler caller (And if that fails, |
| 313 | return 0). */ |
| 314 | if ((get_frame_type (fi) == SIGTRAMP_FRAME)) |
| 315 | return fi->next ? fi->next->pc : 0; |
| 316 | else |
| 317 | return read_memory_integer (fi->frame + 4, 4); |
| 318 | } |
| 319 | |
| 320 | static void |
| 321 | i386_interix_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch) |
| 322 | { |
| 323 | struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); |
| 324 | |
| 325 | tdep->struct_return = reg_struct_return; |
| 326 | tdep->jb_pc_offset = jump_buffer_Eip_offset; |
| 327 | |
| 328 | set_gdbarch_decr_pc_after_break (gdbarch, 0); |
| 329 | set_gdbarch_pc_in_sigtramp (gdbarch, i386_interix_pc_in_sigtramp); |
| 330 | set_gdbarch_in_solib_call_trampoline (gdbarch, |
| 331 | i386_interix_in_solib_call_trampoline); |
| 332 | set_gdbarch_skip_trampoline_code (gdbarch, |
| 333 | i386_interix_skip_trampoline_code); |
| 334 | set_gdbarch_deprecated_init_extra_frame_info (gdbarch, i386_interix_back_one_frame); |
| 335 | set_gdbarch_deprecated_frame_chain_valid (gdbarch, i386_interix_frame_chain_valid); |
| 336 | set_gdbarch_deprecated_frame_saved_pc (gdbarch, i386_interix_frame_saved_pc); |
| 337 | set_gdbarch_name_of_malloc (gdbarch, "_malloc"); |
| 338 | } |
| 339 | |
| 340 | static enum gdb_osabi |
| 341 | i386_interix_osabi_sniffer (bfd * abfd) |
| 342 | { |
| 343 | char *target_name = bfd_get_target (abfd); |
| 344 | |
| 345 | if (strcmp (target_name, "pei-i386") == 0) |
| 346 | return GDB_OSABI_INTERIX; |
| 347 | |
| 348 | return GDB_OSABI_UNKNOWN; |
| 349 | } |
| 350 | |
| 351 | void |
| 352 | _initialize_i386_interix_tdep (void) |
| 353 | { |
| 354 | gdbarch_register_osabi_sniffer (bfd_arch_i386, bfd_target_coff_flavour, |
| 355 | i386_interix_osabi_sniffer); |
| 356 | |
| 357 | gdbarch_register_osabi (bfd_arch_i386, 0, GDB_OSABI_INTERIX, |
| 358 | i386_interix_init_abi); |
| 359 | } |