| 1 | /* Thread management interface, for the remote server for GDB. |
| 2 | Copyright 2002 |
| 3 | Free Software Foundation, Inc. |
| 4 | |
| 5 | Contributed by MontaVista Software. |
| 6 | |
| 7 | This file is part of GDB. |
| 8 | |
| 9 | This program is free software; you can redistribute it and/or modify |
| 10 | it under the terms of the GNU General Public License as published by |
| 11 | the Free Software Foundation; either version 2 of the License, or |
| 12 | (at your option) any later version. |
| 13 | |
| 14 | This program is distributed in the hope that it will be useful, |
| 15 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 16 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 17 | GNU General Public License for more details. |
| 18 | |
| 19 | You should have received a copy of the GNU General Public License |
| 20 | along with this program; if not, write to the Free Software |
| 21 | Foundation, Inc., 59 Temple Place - Suite 330, |
| 22 | Boston, MA 02111-1307, USA. */ |
| 23 | |
| 24 | #include "server.h" |
| 25 | |
| 26 | #include "linux-low.h" |
| 27 | |
| 28 | extern int debug_threads; |
| 29 | |
| 30 | #ifdef HAVE_THREAD_DB_H |
| 31 | #include <thread_db.h> |
| 32 | #endif |
| 33 | |
| 34 | /* Correct for all GNU/Linux targets (for quite some time). */ |
| 35 | #define GDB_GREGSET_T elf_gregset_t |
| 36 | #define GDB_FPREGSET_T elf_fpregset_t |
| 37 | |
| 38 | #ifndef HAVE_ELF_FPREGSET_T |
| 39 | /* Make sure we have said types. Not all platforms bring in <linux/elf.h> |
| 40 | via <sys/procfs.h>. */ |
| 41 | #ifdef HAVE_LINUX_ELF_H |
| 42 | #include <linux/elf.h> |
| 43 | #endif |
| 44 | #endif |
| 45 | |
| 46 | #include "../gdb_proc_service.h" |
| 47 | |
| 48 | /* Structure that identifies the child process for the |
| 49 | <proc_service.h> interface. */ |
| 50 | static struct ps_prochandle proc_handle; |
| 51 | |
| 52 | /* Connection to the libthread_db library. */ |
| 53 | static td_thragent_t *thread_agent; |
| 54 | |
| 55 | static int find_new_threads_callback (const td_thrhandle_t *th_p, void *data); |
| 56 | |
| 57 | static char * |
| 58 | thread_db_err_str (td_err_e err) |
| 59 | { |
| 60 | static char buf[64]; |
| 61 | |
| 62 | switch (err) |
| 63 | { |
| 64 | case TD_OK: |
| 65 | return "generic 'call succeeded'"; |
| 66 | case TD_ERR: |
| 67 | return "generic error"; |
| 68 | case TD_NOTHR: |
| 69 | return "no thread to satisfy query"; |
| 70 | case TD_NOSV: |
| 71 | return "no sync handle to satisfy query"; |
| 72 | case TD_NOLWP: |
| 73 | return "no LWP to satisfy query"; |
| 74 | case TD_BADPH: |
| 75 | return "invalid process handle"; |
| 76 | case TD_BADTH: |
| 77 | return "invalid thread handle"; |
| 78 | case TD_BADSH: |
| 79 | return "invalid synchronization handle"; |
| 80 | case TD_BADTA: |
| 81 | return "invalid thread agent"; |
| 82 | case TD_BADKEY: |
| 83 | return "invalid key"; |
| 84 | case TD_NOMSG: |
| 85 | return "no event message for getmsg"; |
| 86 | case TD_NOFPREGS: |
| 87 | return "FPU register set not available"; |
| 88 | case TD_NOLIBTHREAD: |
| 89 | return "application not linked with libthread"; |
| 90 | case TD_NOEVENT: |
| 91 | return "requested event is not supported"; |
| 92 | case TD_NOCAPAB: |
| 93 | return "capability not available"; |
| 94 | case TD_DBERR: |
| 95 | return "debugger service failed"; |
| 96 | case TD_NOAPLIC: |
| 97 | return "operation not applicable to"; |
| 98 | case TD_NOTSD: |
| 99 | return "no thread-specific data for this thread"; |
| 100 | case TD_MALLOC: |
| 101 | return "malloc failed"; |
| 102 | case TD_PARTIALREG: |
| 103 | return "only part of register set was written/read"; |
| 104 | case TD_NOXREGS: |
| 105 | return "X register set not available for this thread"; |
| 106 | default: |
| 107 | snprintf (buf, sizeof (buf), "unknown thread_db error '%d'", err); |
| 108 | return buf; |
| 109 | } |
| 110 | } |
| 111 | |
| 112 | #if 0 |
| 113 | static char * |
| 114 | thread_db_state_str (td_thr_state_e state) |
| 115 | { |
| 116 | static char buf[64]; |
| 117 | |
| 118 | switch (state) |
| 119 | { |
| 120 | case TD_THR_STOPPED: |
| 121 | return "stopped by debugger"; |
| 122 | case TD_THR_RUN: |
| 123 | return "runnable"; |
| 124 | case TD_THR_ACTIVE: |
| 125 | return "active"; |
| 126 | case TD_THR_ZOMBIE: |
| 127 | return "zombie"; |
| 128 | case TD_THR_SLEEP: |
| 129 | return "sleeping"; |
| 130 | case TD_THR_STOPPED_ASLEEP: |
| 131 | return "stopped by debugger AND blocked"; |
| 132 | default: |
| 133 | snprintf (buf, sizeof (buf), "unknown thread_db state %d", state); |
| 134 | return buf; |
| 135 | } |
| 136 | } |
| 137 | #endif |
| 138 | |
| 139 | static void |
| 140 | thread_db_create_event (CORE_ADDR where) |
| 141 | { |
| 142 | td_event_msg_t msg; |
| 143 | td_err_e err; |
| 144 | struct inferior_linux_data *tdata; |
| 145 | |
| 146 | if (debug_threads) |
| 147 | fprintf (stderr, "Thread creation event.\n"); |
| 148 | |
| 149 | tdata = inferior_target_data (current_inferior); |
| 150 | |
| 151 | /* FIXME: This assumes we don't get another event. |
| 152 | In the LinuxThreads implementation, this is safe, |
| 153 | because all events come from the manager thread |
| 154 | (except for its own creation, of course). */ |
| 155 | err = td_ta_event_getmsg (thread_agent, &msg); |
| 156 | if (err != TD_OK) |
| 157 | fprintf (stderr, "thread getmsg err: %s\n", |
| 158 | thread_db_err_str (err)); |
| 159 | |
| 160 | /* msg.event == TD_EVENT_CREATE */ |
| 161 | |
| 162 | find_new_threads_callback (msg.th_p, NULL); |
| 163 | } |
| 164 | |
| 165 | #if 0 |
| 166 | static void |
| 167 | thread_db_death_event (CORE_ADDR where) |
| 168 | { |
| 169 | if (debug_threads) |
| 170 | fprintf (stderr, "Thread death event.\n"); |
| 171 | } |
| 172 | #endif |
| 173 | |
| 174 | static int |
| 175 | thread_db_enable_reporting () |
| 176 | { |
| 177 | td_thr_events_t events; |
| 178 | td_notify_t notify; |
| 179 | td_err_e err; |
| 180 | |
| 181 | /* Set the process wide mask saying which events we're interested in. */ |
| 182 | td_event_emptyset (&events); |
| 183 | td_event_addset (&events, TD_CREATE); |
| 184 | |
| 185 | #if 0 |
| 186 | /* This is reported to be broken in glibc 2.1.3. A different approach |
| 187 | will be necessary to support that. */ |
| 188 | td_event_addset (&events, TD_DEATH); |
| 189 | #endif |
| 190 | |
| 191 | err = td_ta_set_event (thread_agent, &events); |
| 192 | if (err != TD_OK) |
| 193 | { |
| 194 | warning ("Unable to set global thread event mask: %s", |
| 195 | thread_db_err_str (err)); |
| 196 | return 0; |
| 197 | } |
| 198 | |
| 199 | /* Get address for thread creation breakpoint. */ |
| 200 | err = td_ta_event_addr (thread_agent, TD_CREATE, ¬ify); |
| 201 | if (err != TD_OK) |
| 202 | { |
| 203 | warning ("Unable to get location for thread creation breakpoint: %s", |
| 204 | thread_db_err_str (err)); |
| 205 | return 0; |
| 206 | } |
| 207 | set_breakpoint_at ((CORE_ADDR) (unsigned long) notify.u.bptaddr, |
| 208 | thread_db_create_event); |
| 209 | |
| 210 | #if 0 |
| 211 | /* Don't concern ourselves with reported thread deaths, only |
| 212 | with actual thread deaths (via wait). */ |
| 213 | |
| 214 | /* Get address for thread death breakpoint. */ |
| 215 | err = td_ta_event_addr (thread_agent, TD_DEATH, ¬ify); |
| 216 | if (err != TD_OK) |
| 217 | { |
| 218 | warning ("Unable to get location for thread death breakpoint: %s", |
| 219 | thread_db_err_str (err)); |
| 220 | return; |
| 221 | } |
| 222 | set_breakpoint_at ((CORE_ADDR) (unsigned long) notify.u.bptaddr, |
| 223 | thread_db_death_event); |
| 224 | #endif |
| 225 | |
| 226 | return 1; |
| 227 | } |
| 228 | |
| 229 | static void |
| 230 | maybe_attach_thread (const td_thrhandle_t *th_p, td_thrinfo_t *ti_p) |
| 231 | { |
| 232 | td_err_e err; |
| 233 | struct thread_info *inferior; |
| 234 | struct process_info *process; |
| 235 | |
| 236 | /* If we are attaching to our first thread, things are a little |
| 237 | different. */ |
| 238 | if (all_threads.head == all_threads.tail) |
| 239 | { |
| 240 | inferior = (struct thread_info *) all_threads.head; |
| 241 | process = get_thread_process (inferior); |
| 242 | if (process->thread_known == 0) |
| 243 | { |
| 244 | /* Switch to indexing the threads list by TID. */ |
| 245 | change_inferior_id (&all_threads, ti_p->ti_tid); |
| 246 | goto found; |
| 247 | } |
| 248 | } |
| 249 | |
| 250 | inferior = (struct thread_info *) find_inferior_id (&all_threads, |
| 251 | ti_p->ti_tid); |
| 252 | if (inferior != NULL) |
| 253 | return; |
| 254 | |
| 255 | if (debug_threads) |
| 256 | fprintf (stderr, "Attaching to thread %ld (LWP %d)\n", |
| 257 | ti_p->ti_tid, ti_p->ti_lid); |
| 258 | linux_attach_lwp (ti_p->ti_lid, ti_p->ti_tid); |
| 259 | inferior = (struct thread_info *) find_inferior_id (&all_threads, |
| 260 | ti_p->ti_tid); |
| 261 | if (inferior == NULL) |
| 262 | { |
| 263 | warning ("Could not attach to thread %ld (LWP %d)\n", |
| 264 | ti_p->ti_tid, ti_p->ti_lid); |
| 265 | return; |
| 266 | } |
| 267 | |
| 268 | process = inferior_target_data (inferior); |
| 269 | |
| 270 | found: |
| 271 | new_thread_notify (ti_p->ti_tid); |
| 272 | |
| 273 | process->tid = ti_p->ti_tid; |
| 274 | process->lwpid = ti_p->ti_lid; |
| 275 | |
| 276 | process->thread_known = 1; |
| 277 | err = td_thr_event_enable (th_p, 1); |
| 278 | if (err != TD_OK) |
| 279 | error ("Cannot enable thread event reporting for %d: %s", |
| 280 | ti_p->ti_lid, thread_db_err_str (err)); |
| 281 | } |
| 282 | |
| 283 | static int |
| 284 | find_new_threads_callback (const td_thrhandle_t *th_p, void *data) |
| 285 | { |
| 286 | td_thrinfo_t ti; |
| 287 | td_err_e err; |
| 288 | |
| 289 | err = td_thr_get_info (th_p, &ti); |
| 290 | if (err != TD_OK) |
| 291 | error ("Cannot get thread info: %s", thread_db_err_str (err)); |
| 292 | |
| 293 | /* Check for zombies. */ |
| 294 | if (ti.ti_state == TD_THR_UNKNOWN || ti.ti_state == TD_THR_ZOMBIE) |
| 295 | return 0; |
| 296 | |
| 297 | maybe_attach_thread (th_p, &ti); |
| 298 | |
| 299 | return 0; |
| 300 | } |
| 301 | |
| 302 | static void |
| 303 | thread_db_find_new_threads (void) |
| 304 | { |
| 305 | td_err_e err; |
| 306 | |
| 307 | /* Iterate over all user-space threads to discover new threads. */ |
| 308 | err = td_ta_thr_iter (thread_agent, find_new_threads_callback, NULL, |
| 309 | TD_THR_ANY_STATE, TD_THR_LOWEST_PRIORITY, |
| 310 | TD_SIGNO_MASK, TD_THR_ANY_USER_FLAGS); |
| 311 | if (err != TD_OK) |
| 312 | error ("Cannot find new threads: %s", thread_db_err_str (err)); |
| 313 | } |
| 314 | |
| 315 | /* Cache all future symbols that thread_db might request. We can not |
| 316 | request symbols at arbitrary states in the remote protocol, only |
| 317 | when the client tells us that new symbols are available. So when |
| 318 | we load the thread library, make sure to check the entire list. */ |
| 319 | |
| 320 | static void |
| 321 | thread_db_look_up_symbols (void) |
| 322 | { |
| 323 | const char **sym_list = td_symbol_list (); |
| 324 | CORE_ADDR unused; |
| 325 | |
| 326 | for (sym_list = td_symbol_list (); *sym_list; sym_list++) |
| 327 | look_up_one_symbol (*sym_list, &unused); |
| 328 | } |
| 329 | |
| 330 | int |
| 331 | thread_db_init () |
| 332 | { |
| 333 | int err; |
| 334 | |
| 335 | /* FIXME drow/2004-10-16: This is the "overall process ID", which |
| 336 | GNU/Linux calls tgid, "thread group ID". When we support |
| 337 | attaching to threads, the original thread may not be the correct |
| 338 | thread. We would have to get the process ID from /proc for NPTL. |
| 339 | For LinuxThreads we could do something similar: follow the chain |
| 340 | of parent processes until we find the highest one we're attached |
| 341 | to, and use its tgid. |
| 342 | |
| 343 | This isn't the only place in gdbserver that assumes that the first |
| 344 | process in the list is the thread group leader. */ |
| 345 | proc_handle.pid = ((struct inferior_list_entry *)current_inferior)->id; |
| 346 | |
| 347 | err = td_ta_new (&proc_handle, &thread_agent); |
| 348 | switch (err) |
| 349 | { |
| 350 | case TD_NOLIBTHREAD: |
| 351 | /* No thread library was detected. */ |
| 352 | return 0; |
| 353 | |
| 354 | case TD_OK: |
| 355 | /* The thread library was detected. */ |
| 356 | |
| 357 | if (thread_db_enable_reporting () == 0) |
| 358 | return 0; |
| 359 | thread_db_find_new_threads (); |
| 360 | thread_db_look_up_symbols (); |
| 361 | return 1; |
| 362 | |
| 363 | default: |
| 364 | warning ("error initializing thread_db library."); |
| 365 | } |
| 366 | |
| 367 | return 0; |
| 368 | } |