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      1 
      2 /*--------------------------------------------------------------------*/
      3 /*--- Handle remote gdb protocol.                    m_gdbserver.c ---*/
      4 /*--------------------------------------------------------------------*/
      5 
      6 /*
      7    This file is part of Valgrind, a dynamic binary instrumentation
      8    framework.
      9 
     10    Copyright (C) 2011-2013 Philippe Waroquiers
     11 
     12    This program is free software; you can redistribute it and/or
     13    modify it under the terms of the GNU General Public License as
     14    published by the Free Software Foundation; either version 2 of the
     15    License, or (at your option) any later version.
     16 
     17    This program is distributed in the hope that it will be useful, but
     18    WITHOUT ANY WARRANTY; without even the implied warranty of
     19    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
     20    General Public License for more details.
     21 
     22    You should have received a copy of the GNU General Public License
     23    along with this program; if not, write to the Free Software
     24    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
     25    02111-1307, USA.
     26 
     27    The GNU General Public License is contained in the file COPYING.
     28 */
     29 
     30 #include "pub_core_basics.h"
     31 #include "pub_core_vki.h"
     32 #include "pub_core_debuglog.h"
     33 #include "pub_core_libcproc.h"
     34 #include "pub_core_libcprint.h"
     35 #include "pub_core_mallocfree.h"
     36 #include "pub_core_threadstate.h"
     37 #include "pub_core_gdbserver.h"
     38 #include "pub_core_options.h"
     39 #include "pub_core_transtab.h"
     40 #include "pub_core_hashtable.h"
     41 #include "pub_core_xarray.h"
     42 #include "pub_core_libcassert.h"
     43 #include "pub_core_libcbase.h"
     44 #include "pub_core_libcsignal.h"
     45 #include "pub_core_signals.h"
     46 #include "pub_core_machine.h"     // VG_(fnptr_to_fnentry)
     47 #include "pub_core_debuginfo.h"
     48 #include "pub_core_scheduler.h"
     49 #include "pub_core_syswrap.h"
     50 
     51 #include "server.h"
     52 
     53 Int VG_(dyn_vgdb_error);
     54 
     55 /* forward declarations */
     56 VG_REGPARM(1)
     57 void VG_(helperc_CallDebugger) ( HWord iaddr );
     58 VG_REGPARM(1)
     59 void VG_(helperc_invalidate_if_not_gdbserved) ( Addr addr );
     60 static void invalidate_current_ip (ThreadId tid, const HChar *who);
     61 
     62 /* reasons of call to call_gdbserver. */
     63 typedef
     64    enum {
     65       init_reason,    // initialises gdbserver resources
     66       vgdb_reason,    // gdbserver invocation by vgdb doing ptrace
     67       core_reason,    // gdbserver invocation by core (e.g. error encountered)
     68       break_reason,   // break encountered
     69       watch_reason,   // watchpoint detected by tool
     70       signal_reason,  // signal encountered
     71       exit_reason}    // process terminated
     72     CallReason;
     73 
     74 static const HChar* ppCallReason(CallReason reason)
     75 {
     76    switch (reason) {
     77    case init_reason:    return "init_reason";
     78    case vgdb_reason:    return "vgdb_reason";
     79    case core_reason:    return "core_reason";
     80    case break_reason:   return "break_reason";
     81    case watch_reason:   return "watch_reason";
     82    case signal_reason:  return "signal_reason";
     83    case exit_reason:    return "exit_reason";
     84    default: vg_assert (0);
     85    }
     86 }
     87 
     88 /* An instruction instrumented for gdbserver looks like this:
     89     1. Ist_Mark (0x1234)
     90     2. Put (IP, 0x1234)
     91     3. helperc_CallDebugger (0x1234)
     92          This will give control to gdb if there is a break at 0x1234
     93          or if we are single stepping
     94     4. ... here the real IR for the instruction at 0x1234
     95 
     96     When there is a break at 0x1234:
     97       if user does "continue" or "step" or similar,
     98         then - the call to debugger returns
     99              - valgrind executes at 3. the real IR(s) for 0x1234
    100 
    101       if as part of helperc_CallDebugger, the user calls
    102       some code in gdb e.g print hello_world()
    103         then - gdb prepares a dummy stack frame with a specific
    104                return address (typically it uses _start) and
    105                inserts a break at this address
    106              - gdb then puts in EIP the address of hello_world()
    107              - gdb then continues (so the helperc_CallDebugger
    108                returns)
    109              - call_gdbserver() function will then return the
    110                control to the scheduler (using VG_MINIMAL_LONGJMP)
    111                to allow the block of the new EIP
    112                to be executed.
    113              - hello_world code is executed.
    114              - when hello_world() returns, it returns to
    115                _start and encounters the break at _start.
    116              - gdb then removes this break, put 0x1234 in EIP
    117                and does a "step". This causes to jump from
    118                _start to 0x1234, where the call to
    119                 helperc_CallDebugger is redone.
    120              - This is all ok, the user can then give new gdb
    121                commands.
    122 
    123     However, when continue is given, address 0x1234 is to
    124     be executed: gdb gives a single step, which must not
    125     report again the break at 0x1234. To avoid a 2nd report
    126     of the same break, the below tells that the next
    127     helperc_CallDebugger call must ignore a break/stop at
    128     this address.
    129 */
    130 static Addr ignore_this_break_once = 0;
    131 
    132 
    133 static void call_gdbserver ( ThreadId tid , CallReason reason);
    134 
    135 /* Describes the address addr (for debugging/printing purposes).
    136    Last two results are kept. A third call will replace the
    137    oldest result. */
    138 static HChar* sym (Addr addr, Bool is_code)
    139 {
    140    static HChar *buf[2];
    141    static int w = 0;
    142    PtrdiffT offset;
    143    if (w == 2) w = 0;
    144 
    145    if (is_code) {
    146       const HChar *name;
    147       name = VG_(describe_IP) (addr, NULL);
    148       if (buf[w]) VG_(free)(buf[w]);
    149       buf[w] = VG_(strdup)("gdbserver sym", name);
    150    } else {
    151       const HChar *name;
    152       VG_(get_datasym_and_offset) (addr, &name, &offset);
    153       if (buf[w]) VG_(free)(buf[w]);
    154       buf[w] = VG_(strdup)("gdbserver sym", name);
    155    }
    156    return buf[w++];
    157 }
    158 
    159 /* Each time gdbserver is called, gdbserver_called is incremented
    160    gdbserver_exited is incremented when gdbserver is asked to exit */
    161 static int gdbserver_called = 0;
    162 static int gdbserver_exited = 0;
    163 
    164 /* alloc and free functions for xarray and similar. */
    165 static void* gs_alloc (const HChar* cc, SizeT sz)
    166 {
    167    return VG_(malloc)(cc, sz);
    168 }
    169 static void gs_free (void* ptr)
    170 {
    171    VG_(free)(ptr);
    172 }
    173 
    174 typedef
    175    enum {
    176      GS_break,
    177      GS_jump
    178    }
    179    GS_Kind;
    180 
    181 typedef
    182    struct _GS_Address {
    183       struct _GS_Address* next;
    184       Addr    addr;
    185       GS_Kind kind;
    186    }
    187    GS_Address;
    188 
    189 /* gs_addresses contains a list of all addresses that have been invalidated
    190    because they have been (or must be) instrumented for gdbserver.
    191    An entry is added in this table when there is a break at this
    192    address (kind == GS_break) or if this address is the jump target of an
    193    exit of a block that has been instrumented for gdbserver while
    194    single stepping (kind == GS_jump).
    195    When gdbserver is not single stepping anymore, all GS_jump entries
    196    are removed, their translations are invalidated.
    197 
    198    Note for ARM: addr in GS_Address is the value without the thumb bit set.
    199 */
    200 static VgHashTable *gs_addresses = NULL;
    201 
    202 // Transform addr in the form stored in the list of addresses.
    203 // For the ARM architecture, we store it with the thumb bit set to 0.
    204 static Addr HT_addr ( Addr addr )
    205 {
    206 #if defined(VGA_arm)
    207   return addr & ~(Addr)1;
    208 #else
    209   return addr;
    210 #endif
    211 }
    212 
    213 static void add_gs_address (Addr addr, GS_Kind kind, const HChar* from)
    214 {
    215    GS_Address *p;
    216 
    217    p = VG_(malloc)(from, sizeof(GS_Address));
    218    p->addr = HT_addr (addr);
    219    p->kind = kind;
    220    VG_(HT_add_node)(gs_addresses, p);
    221    /* It should be sufficient to discard a range of 1.
    222       We use 2 to ensure the below is not sensitive to the presence
    223       of thumb bit in the range of addresses to discard.
    224       No need to discard translations for Vg_VgdbFull as all
    225       instructions are in any case vgdb-instrumented. */
    226    if (VG_(clo_vgdb) != Vg_VgdbFull)
    227       VG_(discard_translations) (addr, 2, from);
    228 }
    229 
    230 static void remove_gs_address (GS_Address* g, const HChar* from)
    231 {
    232    VG_(HT_remove) (gs_addresses, g->addr);
    233    // See add_gs_address for the explanation for condition and the range 2 below.
    234    if (VG_(clo_vgdb) != Vg_VgdbFull)
    235       VG_(discard_translations) (g->addr, 2, from);
    236    VG_(free) (g);
    237 }
    238 
    239 const HChar* VG_(ppPointKind) (PointKind kind)
    240 {
    241    switch(kind) {
    242    case software_breakpoint: return "software_breakpoint";
    243    case hardware_breakpoint: return "hardware_breakpoint";
    244    case write_watchpoint:    return "write_watchpoint";
    245    case read_watchpoint:     return "read_watchpoint";
    246    case access_watchpoint:   return "access_watchpoint";
    247    default:                  return "???wrong PointKind";
    248    }
    249 }
    250 
    251 typedef
    252    struct _GS_Watch {
    253       Addr    addr;
    254       SizeT   len;
    255       PointKind kind;
    256    }
    257    GS_Watch;
    258 
    259 /* gs_watches contains a list of all addresses+len+kind that are being
    260    watched. */
    261 static XArray* gs_watches = NULL;
    262 
    263 static inline GS_Watch* index_gs_watches(Word i)
    264 {
    265    return *(GS_Watch **) VG_(indexXA) (gs_watches, i);
    266 }
    267 
    268 /* Returns the GS_Watch matching addr/len/kind and sets *g_ix to its
    269    position in gs_watches.
    270    If no matching GS_Watch is found, returns NULL and sets g_ix to -1. */
    271 static GS_Watch* lookup_gs_watch (Addr addr, SizeT len, PointKind kind,
    272                                   Word* g_ix)
    273 {
    274    const Word n_elems = VG_(sizeXA) (gs_watches);
    275    Word i;
    276    GS_Watch *g;
    277 
    278    /* Linear search. If we have many watches, this might be optimised
    279       by having the array sorted and using VG_(lookupXA) */
    280    for (i = 0; i < n_elems; i++) {
    281       g = index_gs_watches(i);
    282       if (g->addr == addr && g->len == len && g->kind == kind) {
    283          // Found.
    284          *g_ix = i;
    285          return g;
    286       }
    287    }
    288 
    289    // Not found.
    290    *g_ix = -1;
    291    return NULL;
    292 }
    293 
    294 
    295 /* protocol spec tells the below must be idempotent. */
    296 static void breakpoint (Bool insert, CORE_ADDR addr)
    297 {
    298    GS_Address *g;
    299 
    300    g = VG_(HT_lookup) (gs_addresses, (UWord)HT_addr(addr));
    301    if (insert) {
    302       /* insert a breakpoint at addr or upgrade its kind */
    303       if (g == NULL) {
    304          add_gs_address (addr, GS_break, "m_gdbserver breakpoint insert");
    305       } else {
    306          /* already gdbserved. Normally, it must be because of a jump.
    307             However, due to idempotent or if connection with gdb was
    308             lost (kept breaks from the previous gdb), if already existing,
    309             we just upgrade its kind. */
    310          g->kind = GS_break;
    311       }
    312    } else {
    313       /* delete a breakpoint at addr or downgrade its kind */
    314       if (g != NULL && g->kind == GS_break) {
    315          if (valgrind_single_stepping()) {
    316             /* keep gdbserved instrumentation while single stepping */
    317             g->kind = GS_jump;
    318          } else {
    319             remove_gs_address (g, "m_gdbserver breakpoint remove");
    320          }
    321       } else {
    322          dlog (1, "remove break addr %p %s\n",
    323                C2v(addr), (g == NULL ?
    324                            "NULL" :
    325                            (g->kind == GS_jump ? "GS_jump" : "GS_break")));
    326       }
    327    }
    328 }
    329 
    330 static Bool (*tool_watchpoint) (PointKind kind,
    331                                 Bool insert,
    332                                 Addr addr,
    333                                 SizeT len) = NULL;
    334 void VG_(needs_watchpoint) (Bool (*watchpoint) (PointKind kind,
    335                                                 Bool insert,
    336                                                 Addr addr,
    337                                                 SizeT len))
    338 {
    339    tool_watchpoint = watchpoint;
    340 }
    341 
    342 Bool VG_(gdbserver_point) (PointKind kind, Bool insert,
    343                            CORE_ADDR addr, int len)
    344 {
    345    Bool res;
    346    GS_Watch *g;
    347    Word g_ix;
    348    Bool is_code = kind == software_breakpoint || kind == hardware_breakpoint;
    349 
    350    dlog(1, "%s %s at addr %p %s\n",
    351         (insert ? "insert" : "remove"),
    352         VG_(ppPointKind) (kind),
    353         C2v(addr),
    354         sym(addr, is_code));
    355 
    356    if (is_code) {
    357       breakpoint (insert, addr);
    358       return True;
    359    }
    360 
    361    vg_assert (kind == access_watchpoint
    362               || kind == read_watchpoint
    363               || kind == write_watchpoint);
    364 
    365    if (tool_watchpoint == NULL)
    366       return False;
    367 
    368    res = (*tool_watchpoint) (kind, insert, addr, len);
    369    if (!res)
    370       return False; /* error or unsupported */
    371 
    372    // Protocol says insert/remove must be idempotent.
    373    // So, we just ignore double insert or (supposed) double delete.
    374 
    375    g = lookup_gs_watch (addr, len, kind, &g_ix);
    376    if (insert) {
    377       if (g == NULL) {
    378          g = VG_(malloc)("gdbserver_point watchpoint", sizeof(GS_Watch));
    379          g->addr = addr;
    380          g->len  = len;
    381          g->kind = kind;
    382          VG_(addToXA)(gs_watches, &g);
    383       } else {
    384          dlog(1,
    385               "VG_(gdbserver_point) addr %p len %d kind %s already inserted\n",
    386                C2v(addr), len, VG_(ppPointKind) (kind));
    387       }
    388    } else {
    389       if (g != NULL) {
    390          VG_(removeIndexXA) (gs_watches, g_ix);
    391          VG_(free) (g);
    392       } else {
    393          dlog(1,
    394               "VG_(gdbserver_point) addr %p len %d kind %s already deleted?\n",
    395               C2v(addr), len, VG_(ppPointKind) (kind));
    396       }
    397    }
    398    return True;
    399 }
    400 
    401 Bool VG_(has_gdbserver_breakpoint) (Addr addr)
    402 {
    403    GS_Address *g;
    404    if (!gdbserver_called)
    405       return False;
    406    g = VG_(HT_lookup) (gs_addresses, (UWord)HT_addr(addr));
    407    return (g != NULL && g->kind == GS_break);
    408 }
    409 
    410 Bool VG_(is_watched)(PointKind kind, Addr addr, Int szB)
    411 {
    412    Word n_elems;
    413    GS_Watch* g;
    414    Word i;
    415    Bool watched = False;
    416    const ThreadId tid = VG_(running_tid);
    417 
    418    if (!gdbserver_called)
    419       return False;
    420 
    421    n_elems = VG_(sizeXA) (gs_watches);
    422 
    423    Addr to = addr + szB; // semi-open interval [addr, to[
    424 
    425    vg_assert (kind == access_watchpoint
    426               || kind == read_watchpoint
    427               || kind == write_watchpoint);
    428    dlog(1, "tid %d VG_(is_watched) %s addr %p szB %d\n",
    429         tid, VG_(ppPointKind) (kind), C2v(addr), szB);
    430 
    431    for (i = 0; i < n_elems; i++) {
    432       g = index_gs_watches(i);
    433       switch (g->kind) {
    434       case software_breakpoint:
    435       case hardware_breakpoint:
    436          break;
    437       case access_watchpoint:
    438       case read_watchpoint:
    439       case write_watchpoint:
    440          if (to <= g->addr || addr >= (g->addr + g->len))
    441             /* If no overlap, examine next watchpoint: */
    442             continue;
    443 
    444          watched = True; /* We have an overlap */
    445 
    446          /* call gdbserver if access kind reported by the tool
    447             matches the watchpoint kind. */
    448          if (kind == access_watchpoint
    449              || g->kind == access_watchpoint
    450              || g->kind == kind) {
    451             /* Watchpoint encountered.
    452                If this is a read watchpoint, we directly call gdbserver
    453                to report it to gdb.
    454                Otherwise, for a write watchpoint, we have to finish
    455                the instruction so as to modify the value.
    456                If we do not finish the instruction, then gdb sees no
    457                value change and continues.
    458                For a read watchpoint, we better call gdbserver directly:
    459                in case the current block is not gdbserved, Valgrind
    460                will execute instructions till the next block. */
    461 
    462             /* set the watchpoint stop address to the first read or written. */
    463             if (g->addr <= addr) {
    464                VG_(set_watchpoint_stop_address) (addr);
    465             } else {
    466                VG_(set_watchpoint_stop_address) (g->addr);
    467             }
    468 
    469             if (kind == write_watchpoint) {
    470                /* Let Valgrind stop as early as possible after this instruction
    471                   by switching to Single Stepping mode. */
    472                valgrind_set_single_stepping (True);
    473                invalidate_current_ip (tid, "m_gdbserver write watchpoint");
    474             } else {
    475                call_gdbserver (tid, watch_reason);
    476                VG_(set_watchpoint_stop_address) ((Addr) 0);
    477             }
    478             return True; // we are watched here.
    479          }
    480          break;
    481       default:
    482          vg_assert (0);
    483       }
    484    }
    485    return watched;
    486 }
    487 
    488 /* Returns the reason for which gdbserver instrumentation is needed */
    489 static VgVgdb VG_(gdbserver_instrumentation_needed) (const VexGuestExtents* vge)
    490 {
    491    GS_Address* g;
    492    int e;
    493 
    494    if (!gdbserver_called)
    495       return Vg_VgdbNo;
    496 
    497    if (valgrind_single_stepping()) {
    498       dlog(2, "gdbserver_instrumentation_needed due to single stepping\n");
    499       return Vg_VgdbYes;
    500    }
    501 
    502    if (VG_(clo_vgdb) == Vg_VgdbYes && VG_(HT_count_nodes) (gs_addresses) == 0)
    503       return Vg_VgdbNo;
    504 
    505    /* We assume we do not have a huge nr of breakpoints.
    506       Otherwise, we need something more efficient e.g.
    507       a sorted list of breakpoints or associate extents to it or ...
    508    */
    509    VG_(HT_ResetIter) (gs_addresses);
    510    while ((g = VG_(HT_Next) (gs_addresses))) {
    511       for (e = 0; e < vge->n_used; e++) {
    512          if (g->addr >= HT_addr(vge->base[e])
    513              && g->addr < HT_addr(vge->base[e]) + vge->len[e]) {
    514             dlog(2,
    515                  "gdbserver_instrumentation_needed %p %s reason %s\n",
    516                  C2v(g->addr), sym(g->addr, /* is_code */ True),
    517                  (g->kind == GS_jump ? "GS_jump" : "GS_break"));
    518             return Vg_VgdbYes;
    519          }
    520       }
    521    }
    522 
    523    if (VG_(clo_vgdb) == Vg_VgdbFull) {
    524       dlog(4, "gdbserver_instrumentation_needed"
    525            " due to VG_(clo_vgdb) == Vg_VgdbFull\n");
    526       return Vg_VgdbFull;
    527    }
    528 
    529 
    530    return Vg_VgdbNo;
    531 }
    532 
    533 // Clear gdbserved_addresses in gs_addresses.
    534 // If clear_only_jumps, clears only the addresses that are served
    535 // for jump reasons.
    536 // Otherwise, clear all the addresses.
    537 // Cleared addresses are invalidated so as to have them re-translated.
    538 static void clear_gdbserved_addresses(Bool clear_only_jumps)
    539 {
    540    GS_Address** ag;
    541    UInt n_elems;
    542    int i;
    543 
    544    dlog(1,
    545         "clear_gdbserved_addresses: scanning hash table nodes %d\n",
    546         VG_(HT_count_nodes) (gs_addresses));
    547    ag = (GS_Address**) VG_(HT_to_array) (gs_addresses, &n_elems);
    548    for (i = 0; i < n_elems; i++)
    549       if (!clear_only_jumps || ag[i]->kind == GS_jump)
    550          remove_gs_address (ag[i], "clear_gdbserved_addresses");
    551    VG_(free) (ag);
    552 }
    553 
    554 // Clear watched addressed in gs_watches, delete gs_watches.
    555 static void clear_watched_addresses(void)
    556 {
    557    GS_Watch* g;
    558    const Word n_elems = VG_(sizeXA) (gs_watches);
    559    Word i;
    560 
    561    dlog(1,
    562         "clear_watched_addresses: %ld elements\n",
    563         n_elems);
    564 
    565    for (i = 0; i < n_elems; i++) {
    566       g = index_gs_watches(i);
    567       if (!VG_(gdbserver_point) (g->kind,
    568                                  /* insert */ False,
    569                                  g->addr,
    570                                  g->len)) {
    571          vg_assert (0);
    572       }
    573    }
    574 
    575    VG_(deleteXA) (gs_watches);
    576    gs_watches = NULL;
    577 }
    578 
    579 static void invalidate_if_jump_not_yet_gdbserved (Addr addr, const HChar* from)
    580 {
    581    if (VG_(HT_lookup) (gs_addresses, (UWord)HT_addr(addr)))
    582       return;
    583    add_gs_address (addr, GS_jump, from);
    584 }
    585 
    586 static void invalidate_current_ip (ThreadId tid, const HChar *who)
    587 {
    588    invalidate_if_jump_not_yet_gdbserved (VG_(get_IP) (tid), who);
    589 }
    590 
    591 Bool VG_(gdbserver_init_done) (void)
    592 {
    593    return gdbserver_called > 0;
    594 }
    595 
    596 Bool VG_(gdbserver_stop_at) (VgdbStopAt stopat)
    597 {
    598    return gdbserver_called > 0 && VgdbStopAtiS(stopat, VG_(clo_vgdb_stop_at));
    599 }
    600 
    601 void VG_(gdbserver_prerun_action) (ThreadId tid)
    602 {
    603    // Using VG_(dyn_vgdb_error) allows the user to control if gdbserver
    604    // stops after a fork.
    605    if (VG_(dyn_vgdb_error) == 0
    606        || VgdbStopAtiS(VgdbStopAt_Startup, VG_(clo_vgdb_stop_at))) {
    607       /* The below call allows gdb to attach at startup
    608          before the first guest instruction is executed. */
    609       VG_(umsg)("(action at startup) vgdb me ... \n");
    610       VG_(gdbserver)(tid);
    611    } else {
    612       /* User has activated gdbserver => initialize now the FIFOs
    613          to let vgdb/gdb contact us either via the scheduler poll
    614          mechanism or via vgdb ptrace-ing valgrind. */
    615       if (VG_(gdbserver_activity) (tid))
    616          VG_(gdbserver) (tid);
    617    }
    618 }
    619 
    620 /* when fork is done, various cleanup is needed in the child process.
    621    In particular, child must have its own connection to avoid stealing
    622    data from its parent */
    623 static void gdbserver_cleanup_in_child_after_fork(ThreadId me)
    624 {
    625    dlog(1, "thread %d gdbserver_cleanup_in_child_after_fork pid %d\n",
    626         me, VG_(getpid) ());
    627 
    628    /* finish connection inheritated from parent */
    629    remote_finish(reset_after_fork);
    630 
    631    /* ensure next call to gdbserver will be considered as a brand
    632       new call that will initialize a fresh gdbserver. */
    633    if (gdbserver_called) {
    634       gdbserver_called = 0;
    635       vg_assert (gs_addresses != NULL);
    636       vg_assert (gs_watches != NULL);
    637       clear_gdbserved_addresses(/* clear only jumps */ False);
    638       VG_(HT_destruct) (gs_addresses, VG_(free));
    639       gs_addresses = NULL;
    640       clear_watched_addresses();
    641    } else {
    642       vg_assert (gs_addresses == NULL);
    643       vg_assert (gs_watches == NULL);
    644    }
    645 
    646 
    647    if (VG_(clo_trace_children)) {
    648       VG_(gdbserver_prerun_action) (me);
    649    }
    650 }
    651 
    652 /* If reason is init_reason, creates the connection resources (e.g.
    653       the FIFOs) to allow a gdb connection to be detected by polling
    654       using remote_desc_activity.
    655    Otherwise (other reasons):
    656        If connection with gdb not yet opened, opens the connection with gdb.
    657        reads gdb remote protocol packets and executes the requested commands.
    658 */
    659 static void call_gdbserver ( ThreadId tid , CallReason reason)
    660 {
    661    ThreadState*     tst = VG_(get_ThreadState)(tid);
    662    int stepping;
    663    Addr saved_pc;
    664 
    665    dlog(1,
    666         "entering call_gdbserver %s ... pid %d tid %d status %s "
    667         "sched_jmpbuf_valid %d\n",
    668         ppCallReason (reason),
    669         VG_(getpid) (), tid, VG_(name_of_ThreadStatus)(tst->status),
    670         tst->sched_jmpbuf_valid);
    671 
    672    /* If we are about to die, then just run server_main() once to get
    673       the resume reply out and return immediately because most of the state
    674       of this tid and process is about to be torn down. */
    675    if (reason == exit_reason) {
    676       server_main();
    677       return;
    678    }
    679 
    680    vg_assert(VG_(is_valid_tid)(tid));
    681    saved_pc = VG_(get_IP) (tid);
    682 
    683    if (gdbserver_exited) {
    684       dlog(0, "call_gdbserver called when gdbserver_exited %d\n",
    685            gdbserver_exited);
    686       return;
    687    }
    688 
    689    if (gdbserver_called == 0) {
    690       vg_assert (gs_addresses == NULL);
    691       vg_assert (gs_watches == NULL);
    692       gs_addresses = VG_(HT_construct)( "gdbserved_addresses" );
    693       gs_watches = VG_(newXA)(gs_alloc,
    694                               "gdbserved_watches",
    695                               gs_free,
    696                               sizeof(GS_Watch*));
    697       VG_(atfork)(NULL, NULL, gdbserver_cleanup_in_child_after_fork);
    698    }
    699    vg_assert (gs_addresses != NULL);
    700    vg_assert (gs_watches != NULL);
    701 
    702    gdbserver_called++;
    703 
    704    /* call gdbserver_init if this is the first call to gdbserver. */
    705    if (gdbserver_called == 1)
    706       gdbserver_init();
    707 
    708    if (reason == init_reason || gdbserver_called == 1)
    709       remote_open(VG_(clo_vgdb_prefix));
    710 
    711    /* if the call reason is to initialize, then return control to
    712       valgrind. After this initialization, gdbserver will be called
    713       again either if there is an error detected by valgrind or
    714       if vgdb sends data to the valgrind process. */
    715    if (reason == init_reason) {
    716       return;
    717    }
    718 
    719    stepping = valgrind_single_stepping();
    720 
    721    server_main();
    722 
    723    ignore_this_break_once = valgrind_get_ignore_break_once();
    724    if (ignore_this_break_once)
    725       dlog(1, "!!! will ignore_this_break_once %s\n",
    726            sym(ignore_this_break_once, /* is_code */ True));
    727 
    728 
    729    if (valgrind_single_stepping()) {
    730       /* we are single stepping. If we were not stepping on entry,
    731          then invalidate the current program counter so as to properly
    732          do single step. In case the program counter was changed by
    733          gdb, this will also invalidate the target address we will
    734          jump to. */
    735       if (!stepping && tid != 0) {
    736          invalidate_current_ip (tid, "m_gdbserver single step");
    737       }
    738    } else {
    739       /* We are not single stepping.  If we were stepping on entry,
    740          then clear the gdbserved addresses.  This will cause all
    741          these gdbserved blocks to be invalidated so that they can be
    742          re-translated without being gdbserved. */
    743       if (stepping)
    744          clear_gdbserved_addresses(/* clear only jumps */ True);
    745    }
    746 
    747    /* can't do sanity check at beginning. At least the stack
    748       check is not yet possible. */
    749    if (gdbserver_called > 1)
    750       VG_(sanity_check_general) (/* force_expensive */ False);
    751 
    752    /* If the PC has been changed by gdb, then we VG_MINIMAL_LONGJMP to
    753       the scheduler to execute the block of the new PC.
    754       Otherwise we just return to continue executing the
    755       current block. */
    756    if (VG_(get_IP) (tid) != saved_pc) {
    757       dlog(1, "tid %d %s PC changed from %s to %s\n",
    758            tid, VG_(name_of_ThreadStatus) (tst->status),
    759            sym(saved_pc, /* is_code */ True),
    760            sym(VG_(get_IP) (tid), /* is_code */ True));
    761       if (tst->status == VgTs_Yielding) {
    762          SysRes sres;
    763          VG_(memset)(&sres, 0, sizeof(SysRes));
    764          VG_(acquire_BigLock)(tid, "gdbsrv VG_MINIMAL_LONGJMP");
    765       }
    766       if (tst->sched_jmpbuf_valid) {
    767          /* resume scheduler */
    768          VG_MINIMAL_LONGJMP(tst->sched_jmpbuf);
    769       }
    770       /* else continue to run */
    771    }
    772    /* continue to run */
    773 }
    774 
    775 /* busy > 0 when gdbserver is currently being called.
    776    busy is used to to avoid vgdb invoking gdbserver
    777    while gdbserver by Valgrind. */
    778 static volatile int busy = 0;
    779 
    780 void VG_(gdbserver) ( ThreadId tid )
    781 {
    782    busy++;
    783    /* called by the rest of valgrind for
    784          --vgdb-error=0 reason
    785       or by scheduler "poll/debug/interrupt" reason
    786       or to terminate. */
    787    if (tid != 0) {
    788       call_gdbserver (tid, core_reason);
    789    } else {
    790       if (gdbserver_called == 0) {
    791          dlog(1, "VG_(gdbserver) called to terminate, nothing to terminate\n");
    792       } else if (gdbserver_exited) {
    793          dlog(0, "VG_(gdbserver) called to terminate again %d\n",
    794               gdbserver_exited);
    795       } else {
    796          gdbserver_terminate();
    797          gdbserver_exited++;
    798       }
    799    }
    800    busy--;
    801 }
    802 
    803 // nr of invoke_gdbserver while gdbserver is already executing.
    804 static int interrupts_while_busy = 0;
    805 
    806 // nr of invoke_gdbserver while gdbserver is not executing.
    807 static int interrupts_non_busy = 0;
    808 
    809 // nr of invoke_gdbserver when some threads are not interruptible.
    810 static int interrupts_non_interruptible = 0;
    811 
    812 /* When all threads are blocked in a system call, the Valgrind
    813    scheduler cannot poll the shared memory for gdbserver activity.  In
    814    such a case, vgdb will force the invokation of gdbserver using
    815    ptrace. To do that, vgdb 'pushes' a call to invoke_gdbserver
    816    on the stack using ptrace. invoke_gdbserver must not return.
    817    Instead, it must call give_control_back_to_vgdb.
    818    vgdb expects to receive a SIGSTOP, which this function generates.
    819    When vgdb gets this SIGSTOP, it knows invoke_gdbserver call
    820    is finished and can reset the Valgrind process in the state prior to
    821    the 'pushed call' (using ptrace again).
    822    This all works well. However, the user must avoid
    823    'kill-9ing' vgdb during such a pushed call, otherwise
    824    the SIGSTOP generated below will be seen by the Valgrind core,
    825    instead of being handled by vgdb. The OS will then handle the SIGSTOP
    826    by stopping the Valgrind process.
    827    We use SIGSTOP as this process cannot be masked. */
    828 
    829 static void give_control_back_to_vgdb(void)
    830 {
    831    /* cause a SIGSTOP to be sent to ourself, so that vgdb takes control.
    832       vgdb will then restore the stack so as to resume the activity
    833       before the ptrace (typically do_syscall_WRK). */
    834    if (VG_(kill)(VG_(getpid)(), VKI_SIGSTOP) != 0)
    835       vg_assert2(0, "SIGSTOP for vgdb could not be generated\n");
    836 
    837    /* If we arrive here, it means a call was pushed on the stack
    838       by vgdb, but during this call, vgdb and/or connection
    839       died. Alternatively, it is a bug in the vgdb<=>Valgrind gdbserver
    840       ptrace handling. */
    841    vg_assert2(0,
    842               "vgdb did not took control. Did you kill vgdb ?\n"
    843               "busy %d vgdb_interrupted_tid %d\n",
    844               busy, vgdb_interrupted_tid);
    845 }
    846 
    847 /* Using ptrace calls, vgdb will force an invocation of gdbserver.
    848    VG_(invoke_gdbserver) is the entry point called through the
    849    vgdb ptrace technique. */
    850 void VG_(invoke_gdbserver) ( int check )
    851 {
    852    /* ******* Avoid non-reentrant function call from here .....
    853       till the ".... till here" below. */
    854 
    855    /* We need to determine the state of the various threads to decide
    856       if we directly invoke gdbserver or if we rather indicate to the
    857       scheduler to invoke the gdbserver.  To decide that, it is
    858       critical to avoid any "coregrind" function call as the ptrace
    859       might have stopped the process in the middle of this (possibly)
    860       non-rentrant function.  So, it is only when all threads are in
    861       an "interruptible" state that we can safely invoke
    862       gdbserver. Otherwise, we let the valgrind scheduler invoke
    863       gdbserver at the next poll.  This poll will be made very soon
    864       thanks to a call to VG_(force_vgdb_poll). */
    865    int n_tid;
    866 
    867    vg_assert (check == 0x8BADF00D);
    868 
    869    if (busy) {
    870       interrupts_while_busy++;
    871       give_control_back_to_vgdb();
    872    }
    873    interrupts_non_busy++;
    874 
    875    /* check if all threads are in an "interruptible" state.  If yes,
    876       we invoke gdbserver. Otherwise, we tell the scheduler to wake up
    877       asap. */
    878    for (n_tid = 1; n_tid < VG_N_THREADS; n_tid++) {
    879       switch (VG_(threads)[n_tid].status) {
    880       /* interruptible states. */
    881       case VgTs_WaitSys:
    882       case VgTs_Yielding:
    883          if (vgdb_interrupted_tid == 0) vgdb_interrupted_tid = n_tid;
    884          break;
    885 
    886       case VgTs_Empty:
    887       case VgTs_Zombie:
    888          break;
    889 
    890       /* non interruptible states. */
    891       case VgTs_Init:
    892       case VgTs_Runnable:
    893          interrupts_non_interruptible++;
    894          VG_(force_vgdb_poll) ();
    895          give_control_back_to_vgdb();
    896 
    897       default:             vg_assert(0);
    898       }
    899    }
    900 
    901    /* .... till here.
    902       From here onwards, function calls are ok: it is
    903       safe to call valgrind core functions: all threads are blocked in
    904       a system call or are yielding or ... */
    905    dlog(1, "invoke_gdbserver running_tid %d vgdb_interrupted_tid %d\n",
    906         VG_(running_tid), vgdb_interrupted_tid);
    907    call_gdbserver (vgdb_interrupted_tid, vgdb_reason);
    908    vgdb_interrupted_tid = 0;
    909    dlog(1,
    910         "exit invoke_gdbserver running_tid %d\n", VG_(running_tid));
    911    give_control_back_to_vgdb();
    912 
    913    vg_assert2(0, "end of invoke_gdbserver reached");
    914 
    915 }
    916 
    917 Bool VG_(gdbserver_activity) (ThreadId tid)
    918 {
    919    Bool ret;
    920    busy++;
    921    if (!gdbserver_called)
    922       call_gdbserver (tid, init_reason);
    923    switch (remote_desc_activity("VG_(gdbserver_activity)")) {
    924    case 0: ret = False; break;
    925    case 1: ret = True; break;
    926    case 2:
    927       remote_finish(reset_after_error);
    928       call_gdbserver (tid, init_reason);
    929       ret = False;
    930       break;
    931    default: vg_assert (0);
    932    }
    933    busy--;
    934    return ret;
    935 }
    936 
    937 static void dlog_signal (const HChar *who, const vki_siginfo_t *info,
    938                          ThreadId tid)
    939 {
    940    dlog(1, "VG core calling %s "
    941         "vki_nr %d %s gdb_nr %d %s tid %d\n",
    942         who,
    943         info->si_signo, VG_(signame)(info->si_signo),
    944         target_signal_from_host (info->si_signo),
    945         target_signal_to_name(target_signal_from_host (info->si_signo)),
    946         tid);
    947 
    948 }
    949 
    950 void VG_(gdbserver_report_fatal_signal) (const vki_siginfo_t *info,
    951                                          ThreadId tid)
    952 {
    953    dlog_signal("VG_(gdbserver_report_fatal_signal)", info, tid);
    954 
    955    if (remote_connected()) {
    956       dlog(1, "already connected, assuming already reported\n");
    957       return;
    958    }
    959 
    960    VG_(umsg)("(action on fatal signal) vgdb me ... \n");
    961 
    962    /* indicate to gdbserver that there is a signal */
    963    gdbserver_signal_encountered (info);
    964 
    965    /* let gdbserver do some work, e.g. show the signal to the user */
    966    call_gdbserver (tid, signal_reason);
    967 
    968 }
    969 
    970 Bool VG_(gdbserver_report_signal) (vki_siginfo_t *info, ThreadId tid)
    971 {
    972    dlog_signal("VG_(gdbserver_report_signal)", info, tid);
    973 
    974    /* if gdbserver is currently not connected, then signal
    975       is to be given to the process */
    976    if (!remote_connected()) {
    977       dlog(1, "not connected => pass\n");
    978       return True;
    979    }
    980    /* if gdb has informed gdbserver that this signal can be
    981       passed directly without informing gdb, then signal is
    982       to be given to the process. */
    983    if (pass_signals[target_signal_from_host(info->si_signo)]) {
    984       dlog(1, "pass_signals => pass\n");
    985       return True;
    986    }
    987 
    988    /* indicate to gdbserver that there is a signal */
    989    gdbserver_signal_encountered (info);
    990 
    991    /* let gdbserver do some work, e.g. show the signal to the user.
    992       User can also decide to ignore the signal or change the signal. */
    993    call_gdbserver (tid, signal_reason);
    994 
    995    /* ask gdbserver what is the final decision */
    996    if (gdbserver_deliver_signal (info)) {
    997       dlog(1, "gdbserver deliver signal\n");
    998       return True;
    999    } else {
   1000       dlog(1, "gdbserver ignore signal\n");
   1001       return False;
   1002    }
   1003 }
   1004 
   1005 void VG_(gdbserver_exit) (ThreadId tid, VgSchedReturnCode tids_schedretcode)
   1006 {
   1007    dlog(1, "VG core calling VG_(gdbserver_exit) tid %d will exit\n", tid);
   1008    if (remote_connected()) {
   1009       /* Make sure vgdb knows we are about to die and why. */
   1010       switch(tids_schedretcode) {
   1011       case VgSrc_None:
   1012          vg_assert (0);
   1013       case VgSrc_ExitThread:
   1014       case VgSrc_ExitProcess:
   1015          gdbserver_process_exit_encountered ('W', VG_(threads)[tid].os_state.exitcode);
   1016          call_gdbserver (tid, exit_reason);
   1017          break;
   1018       case VgSrc_FatalSig:
   1019          gdbserver_process_exit_encountered ('X', VG_(threads)[tid].os_state.fatalsig);
   1020          call_gdbserver (tid, exit_reason);
   1021          break;
   1022       default:
   1023          vg_assert(0);
   1024       }
   1025    } else {
   1026       dlog(1, "not connected\n");
   1027    }
   1028 
   1029    /* Tear down the connection if it still exists. */
   1030    VG_(gdbserver) (0);
   1031 }
   1032 
   1033 // Check if single_stepping or if there is a break requested at iaddr.
   1034 // If yes, call debugger
   1035 VG_REGPARM(1)
   1036 void VG_(helperc_CallDebugger) ( HWord iaddr )
   1037 {
   1038    GS_Address* g;
   1039 
   1040    // For Vg_VgdbFull, after a fork, we might have calls to this helper
   1041    // while gdbserver is not yet initialized.
   1042    if (!gdbserver_called)
   1043       return;
   1044 
   1045    if (valgrind_single_stepping() ||
   1046        ((g = VG_(HT_lookup) (gs_addresses, (UWord)HT_addr(iaddr))) &&
   1047         (g->kind == GS_break))) {
   1048       if (iaddr == HT_addr(ignore_this_break_once)) {
   1049          dlog(1, "ignoring ignore_this_break_once %s\n",
   1050               sym(ignore_this_break_once, /* is_code */ True));
   1051          ignore_this_break_once = 0;
   1052       } else {
   1053          call_gdbserver (VG_(get_running_tid)(), break_reason);
   1054       }
   1055    }
   1056 }
   1057 
   1058 /* software_breakpoint support --------------------------------------*/
   1059 /* When a block is instrumented for gdbserver, single step and breaks
   1060    will be obeyed in this block.  However, if a jump to another block
   1061    is executed while single_stepping is active, we must ensure that
   1062    this block is also instrumented. For this, when a block is
   1063    instrumented for gdbserver while single_stepping, the target of all
   1064    the Jump instructions in this block will be checked to verify if
   1065    the block is already instrumented for gdbserver.  The below will
   1066    ensure that if not already instrumented for gdbserver, the target
   1067    block translation containing addr will be invalidated.  The list of
   1068    gdbserved Addr will also be kept so that translations can be
   1069    dropped automatically by gdbserver when going out of single step
   1070    mode.
   1071 
   1072    Call the below at translation time if the jump target is a constant.
   1073    Otherwise, rather use VG_(add_stmt_call_invalidate_if_not_gdbserved).
   1074 
   1075    To instrument the target exit statement, you can call
   1076    VG_(add_stmt_call_invalidate_exit_target_if_not_gdbserved) rather
   1077    than check the kind of target exit. */
   1078 static void VG_(invalidate_if_not_gdbserved) (Addr addr)
   1079 {
   1080    if (valgrind_single_stepping())
   1081       invalidate_if_jump_not_yet_gdbserved
   1082          (addr, "gdbserver target jump (instrument)");
   1083 }
   1084 
   1085 // same as VG_(invalidate_if_not_gdbserved) but is intended to be called
   1086 // at runtime (only difference is the invalidate reason which traces
   1087 // it is at runtime)
   1088 VG_REGPARM(1)
   1089 void VG_(helperc_invalidate_if_not_gdbserved) ( Addr addr )
   1090 {
   1091    if (valgrind_single_stepping())
   1092       invalidate_if_jump_not_yet_gdbserved
   1093          (addr, "gdbserver target jump (runtime)");
   1094 }
   1095 
   1096 static void VG_(add_stmt_call_invalidate_if_not_gdbserved)
   1097      ( IRSB* sb_in,
   1098        const VexGuestLayout* layout,
   1099        const VexGuestExtents* vge,
   1100        IRTemp jmp,
   1101        IRSB* irsb)
   1102 {
   1103 
   1104    void*    fn;
   1105    const HChar*   nm;
   1106    IRExpr** args;
   1107    Int      nargs;
   1108    IRDirty* di;
   1109 
   1110    fn    = &VG_(helperc_invalidate_if_not_gdbserved);
   1111    nm    = "VG_(helperc_invalidate_if_not_gdbserved)";
   1112    args  = mkIRExprVec_1(IRExpr_RdTmp (jmp));
   1113    nargs = 1;
   1114 
   1115    di = unsafeIRDirty_0_N( nargs/*regparms*/, nm,
   1116                            VG_(fnptr_to_fnentry)( fn ), args );
   1117 
   1118    di->nFxState = 0;
   1119 
   1120    addStmtToIRSB(irsb, IRStmt_Dirty(di));
   1121 }
   1122 
   1123 /* software_breakpoint support --------------------------------------*/
   1124 /* If a tool wants to allow gdbserver to do something at Addr, then
   1125    VG_(add_stmt_call_gdbserver) will add in IRSB a call to a helper
   1126    function.  This helper function will check if the process must be
   1127    stopped at the instruction Addr: either there is a break at Addr or
   1128    the process is being single-stepped.  Typical usage of the below is to
   1129    instrument an Ist_IMark to allow the debugger to interact at any
   1130    instruction being executed.  As soon as there is one break in a block,
   1131    then to allow single stepping in this block (and possible insertions
   1132    of other breaks in the same sb_in while the process is stopped), a
   1133    debugger statement will be inserted for all instructions of a block. */
   1134 static void VG_(add_stmt_call_gdbserver)
   1135      (IRSB* sb_in,                /* block being translated */
   1136       const VexGuestLayout* layout,
   1137       const VexGuestExtents* vge,
   1138       IRType gWordTy, IRType hWordTy,
   1139       Addr  iaddr,                /* Addr of instruction being instrumented */
   1140       UChar delta,                /* delta to add to iaddr to obtain IP */
   1141       IRSB* irsb)                 /* irsb block to which call is added */
   1142 {
   1143    void*    fn;
   1144    const HChar*   nm;
   1145    IRExpr** args;
   1146    Int      nargs;
   1147    IRDirty* di;
   1148 
   1149    /* first store the address in the program counter so that the check
   1150       done by VG_(helperc_CallDebugger) will be based on the correct
   1151       program counter.  We might make this more efficient by rather
   1152       searching for assignement to program counter and instrumenting
   1153       that but the below is easier and I guess that the optimiser will
   1154       remove the redundant store. And in any case, when debugging a
   1155       piece of code, the efficiency requirement is not critical: very
   1156       few blocks will be instrumented for debugging. */
   1157 
   1158    /* For platforms on which the IP can differ from the addr of the instruction
   1159       being executed, we need to add the delta to obtain the IP.
   1160       This IP will be given to gdb (e.g. if a breakpoint is put at iaddr).
   1161 
   1162       For ARM, this delta will ensure that the thumb bit is set in the
   1163       IP when executing thumb code. gdb uses this thumb bit a.o.
   1164       to properly guess the next IP for the 'step' and 'stepi' commands. */
   1165    vg_assert(delta <= 1);
   1166    addStmtToIRSB(irsb, IRStmt_Put(layout->offset_IP ,
   1167                                   mkIRExpr_HWord(iaddr + (Addr)delta)));
   1168 
   1169    fn    = &VG_(helperc_CallDebugger);
   1170    nm    = "VG_(helperc_CallDebugger)";
   1171    args  = mkIRExprVec_1(mkIRExpr_HWord (iaddr));
   1172    nargs = 1;
   1173 
   1174    di = unsafeIRDirty_0_N( nargs/*regparms*/, nm,
   1175                            VG_(fnptr_to_fnentry)( fn ), args );
   1176 
   1177    /* Note: in fact, a debugger call can read whatever register
   1178       or memory. It can also write whatever register or memory.
   1179       So, in theory, we have to indicate the whole universe
   1180       can be read and modified. It is however not critical
   1181       to indicate precisely what is being read/written
   1182       as such indications are needed for tool error detection
   1183       and we do not want to have errors being detected for
   1184       gdb interactions. */
   1185 
   1186    di->nFxState = 2;
   1187    di->fxState[0].fx        = Ifx_Read;
   1188    di->fxState[0].offset    = layout->offset_SP;
   1189    di->fxState[0].size      = layout->sizeof_SP;
   1190    di->fxState[0].nRepeats  = 0;
   1191    di->fxState[0].repeatLen = 0;
   1192    di->fxState[1].fx        = Ifx_Modify;
   1193    di->fxState[1].offset    = layout->offset_IP;
   1194    di->fxState[1].size      = layout->sizeof_IP;
   1195    di->fxState[1].nRepeats  = 0;
   1196    di->fxState[1].repeatLen = 0;
   1197 
   1198    addStmtToIRSB(irsb, IRStmt_Dirty(di));
   1199 
   1200 }
   1201 
   1202 
   1203 /* Invalidate the target of the exit if needed:
   1204    If target is constant, it is invalidated at translation time.
   1205    Otherwise, a call to a helper function is generated to invalidate
   1206    the translation at run time.
   1207    The below is thus calling either VG_(invalidate_if_not_gdbserved)
   1208    or VG_(add_stmt_call_invalidate_if_not_gdbserved).  */
   1209 static void VG_(add_stmt_call_invalidate_exit_target_if_not_gdbserved)
   1210    (IRSB* sb_in,
   1211     const VexGuestLayout* layout,
   1212     const VexGuestExtents* vge,
   1213     IRType gWordTy,
   1214     IRSB* irsb)
   1215 {
   1216    if (sb_in->next->tag == Iex_Const) {
   1217      VG_(invalidate_if_not_gdbserved) (gWordTy == Ity_I64 ?
   1218                                        sb_in->next->Iex.Const.con->Ico.U64
   1219                                        : sb_in->next->Iex.Const.con->Ico.U32);
   1220    } else if (sb_in->next->tag == Iex_RdTmp) {
   1221      VG_(add_stmt_call_invalidate_if_not_gdbserved)
   1222        (sb_in, layout, vge, sb_in->next->Iex.RdTmp.tmp, irsb);
   1223    } else {
   1224      vg_assert (0); /* unexpected expression tag in exit. */
   1225    }
   1226 }
   1227 
   1228 IRSB* VG_(instrument_for_gdbserver_if_needed)
   1229      (IRSB* sb_in,
   1230       const VexGuestLayout* layout,
   1231       const VexGuestExtents* vge,
   1232       IRType gWordTy, IRType hWordTy)
   1233 {
   1234    IRSB* sb_out;
   1235    Int i;
   1236    const VgVgdb instr_needed = VG_(gdbserver_instrumentation_needed) (vge);
   1237 
   1238    if (instr_needed == Vg_VgdbNo)
   1239      return sb_in;
   1240 
   1241 
   1242    /* here, we need to instrument for gdbserver */
   1243    sb_out = deepCopyIRSBExceptStmts(sb_in);
   1244 
   1245    for (i = 0; i < sb_in->stmts_used; i++) {
   1246       IRStmt* st = sb_in->stmts[i];
   1247 
   1248       if (!st || st->tag == Ist_NoOp) continue;
   1249 
   1250       if (st->tag == Ist_Exit && instr_needed == Vg_VgdbYes) {
   1251         VG_(invalidate_if_not_gdbserved)
   1252           (hWordTy == Ity_I64 ?
   1253            st->Ist.Exit.dst->Ico.U64 :
   1254            st->Ist.Exit.dst->Ico.U32);
   1255       }
   1256       addStmtToIRSB( sb_out, st );
   1257       if (st->tag == Ist_IMark) {
   1258          /* For an Ist_Mark, add a call to debugger. */
   1259          switch (instr_needed) {
   1260          case Vg_VgdbNo: vg_assert (0);
   1261          case Vg_VgdbYes:
   1262          case Vg_VgdbFull:
   1263             VG_(add_stmt_call_gdbserver) ( sb_in, layout, vge,
   1264                                            gWordTy, hWordTy,
   1265                                            st->Ist.IMark.addr,
   1266                                            st->Ist.IMark.delta,
   1267                                            sb_out);
   1268             /* There is an optimisation possible here for Vg_VgdbFull:
   1269                Put a guard ensuring we only call gdbserver if 'FullCallNeeded'.
   1270                FullCallNeeded would be set to 1 we have just switched on
   1271                Single Stepping or have just encountered a watchpoint
   1272                or have just inserted a breakpoint.
   1273                (as gdb by default removes and re-insert breakpoints), we would
   1274                need to also implement the notion of 'breakpoint pending removal'
   1275                to remove at the next 'continue/step' packet. */
   1276             break;
   1277          default: vg_assert (0);
   1278          }
   1279       }
   1280    }
   1281 
   1282    if (instr_needed == Vg_VgdbYes) {
   1283       VG_(add_stmt_call_invalidate_exit_target_if_not_gdbserved) (sb_in,
   1284                                                                   layout, vge,
   1285                                                                   gWordTy,
   1286                                                                   sb_out);
   1287    }
   1288 
   1289    return sb_out;
   1290 }
   1291 
   1292 struct mon_out_buf {
   1293    HChar buf[DATASIZ+1];
   1294    int next;
   1295    UInt ret;
   1296 };
   1297 
   1298 static void mon_out (HChar c, void *opaque)
   1299 {
   1300    struct mon_out_buf *b = (struct mon_out_buf *) opaque;
   1301    b->ret++;
   1302    b->buf[b->next] = c;
   1303    b->next++;
   1304    if (b->next == DATASIZ) {
   1305       b->buf[b->next] = '\0';
   1306       monitor_output(b->buf);
   1307       b->next = 0;
   1308    }
   1309 }
   1310 UInt VG_(gdb_printf) ( const HChar *format, ... )
   1311 {
   1312    struct mon_out_buf b;
   1313 
   1314    b.next = 0;
   1315    b.ret = 0;
   1316 
   1317    va_list vargs;
   1318    va_start(vargs, format);
   1319    VG_(vcbprintf) (mon_out, &b, format, vargs);
   1320    va_end(vargs);
   1321 
   1322    if (b.next > 0) {
   1323       b.buf[b.next] = '\0';
   1324       monitor_output(b.buf);
   1325    }
   1326    return b.ret;
   1327 }
   1328 
   1329 Int VG_(keyword_id) (const HChar* keywords, const HChar* input_word,
   1330                      kwd_report_error report)
   1331 {
   1332    const Int il = (input_word == NULL ? 0 : VG_(strlen) (input_word));
   1333    HChar  iw[il+1];
   1334    HChar  kwds[VG_(strlen)(keywords)+1];
   1335    HChar  *kwdssaveptr;
   1336 
   1337    HChar* kw; /* current keyword, its length, its position */
   1338    Int   kwl;
   1339    Int   kpos = -1;
   1340 
   1341    Int pass;
   1342    /* pass 0 = search, optional pass 1 = output message multiple matches */
   1343 
   1344    Int pass1needed = 0;
   1345 
   1346    Int partial_match = -1;
   1347    Int full_match = -1;
   1348 
   1349    if (input_word == NULL) {
   1350       iw[0] = 0;
   1351       partial_match = 0; /* to force an empty string to cause an error */
   1352    } else {
   1353       VG_(strcpy) (iw, input_word);
   1354    }
   1355 
   1356    for (pass = 0; pass < 2; pass++) {
   1357       VG_(strcpy) (kwds, keywords);
   1358       if (pass == 1)
   1359          VG_(gdb_printf) ("%s can match",
   1360                           (il == 0 ? "<empty string>" : iw));
   1361       for (kw = VG_(strtok_r) (kwds, " ", &kwdssaveptr);
   1362            kw != NULL;
   1363            kw = VG_(strtok_r) (NULL, " ", &kwdssaveptr)) {
   1364          kwl = VG_(strlen) (kw);
   1365          kpos++;
   1366 
   1367          if (il > kwl) {
   1368             ; /* ishtar !~ is */
   1369          } else if (il == kwl) {
   1370             if (VG_(strcmp) (kw, iw) == 0) {
   1371                /* exact match */
   1372                if (pass == 1)
   1373                   VG_(gdb_printf) (" %s", kw);
   1374                if (full_match != -1)
   1375                   pass1needed++;
   1376                full_match = kpos;
   1377             }
   1378          } else {
   1379             /* il < kwl */
   1380             if (VG_(strncmp) (iw, kw, il) == 0) {
   1381                /* partial match */
   1382                if (pass == 1)
   1383                   VG_(gdb_printf) (" %s", kw);
   1384                if (partial_match != -1)
   1385                   pass1needed++;
   1386                partial_match = kpos;
   1387             }
   1388          }
   1389       }
   1390       /* check for success or for no match at all */
   1391       if (pass1needed == 0) {
   1392          if (full_match != -1) {
   1393             return full_match;
   1394          } else {
   1395             if (report == kwd_report_all && partial_match == -1) {
   1396                VG_(gdb_printf) ("%s does not match any of '%s'\n",
   1397                                 iw, keywords);
   1398             }
   1399             return partial_match;
   1400          }
   1401       }
   1402 
   1403       /* here we have duplicated match error */
   1404       if (pass == 1 || report == kwd_report_none) {
   1405          if (report != kwd_report_none) {
   1406             VG_(gdb_printf) ("\n");
   1407          }
   1408          if (partial_match != -1 || full_match != -1)
   1409             return -2;
   1410          else
   1411             return -1;
   1412       }
   1413    }
   1414    /* UNREACHED */
   1415    vg_assert (0);
   1416 }
   1417 
   1418 /* True if string can be a 0x number */
   1419 static Bool is_zero_x (const HChar *s)
   1420 {
   1421    if (strlen (s) >= 3 && s[0] == '0' && s[1] == 'x')
   1422       return True;
   1423    else
   1424       return False;
   1425 }
   1426 
   1427 /* True if string can be a 0b number */
   1428 static Bool is_zero_b (const HChar *s)
   1429 {
   1430    if (strlen (s) >= 3 && s[0] == '0' && s[1] == 'b')
   1431       return True;
   1432    else
   1433       return False;
   1434 }
   1435 
   1436 Bool VG_(strtok_get_address_and_size) (Addr* address,
   1437                                        SizeT* szB,
   1438                                        HChar **ssaveptr)
   1439 {
   1440    HChar* wa;
   1441    HChar* ws;
   1442    HChar* endptr;
   1443    const HChar *ppc;
   1444 
   1445    wa = VG_(strtok_r) (NULL, " ", ssaveptr);
   1446    ppc = wa;
   1447    if (ppc == NULL || !VG_(parse_Addr) (&ppc, address)) {
   1448       VG_(gdb_printf) ("missing or malformed address\n");
   1449       *address = (Addr) 0;
   1450       *szB = 0;
   1451       return False;
   1452    }
   1453    ws = VG_(strtok_r) (NULL, " ", ssaveptr);
   1454    if (ws == NULL) {
   1455       /* Do nothing, i.e. keep current value of szB. */ ;
   1456    } else if (is_zero_x (ws)) {
   1457       *szB = VG_(strtoull16) (ws, &endptr);
   1458    } else if (is_zero_b (ws)) {
   1459       Int j;
   1460       HChar *parsews = ws;
   1461       Int n_bits = VG_(strlen) (ws) - 2;
   1462       *szB = 0;
   1463       ws = NULL; // assume the below loop gives a correct nr.
   1464       for (j = 0; j < n_bits; j++) {
   1465          if      ('0' == parsews[j+2]) { /* do nothing */ }
   1466          else if ('1' == parsews[j+2]) *szB |= (1 << (n_bits-j-1));
   1467          else {
   1468             /* report malformed binary integer */
   1469             ws = parsews;
   1470             endptr = ws + j + 2;
   1471             break;
   1472          }
   1473       }
   1474    } else {
   1475       *szB = VG_(strtoull10) (ws, &endptr);
   1476    }
   1477 
   1478    if (ws != NULL && *endptr != '\0') {
   1479       VG_(gdb_printf) ("malformed integer, expecting "
   1480                        "hex 0x..... or dec ...... or binary .....b\n");
   1481       *address = (Addr) 0;
   1482       *szB = 0;
   1483       return False;
   1484    }
   1485    return True;
   1486 }
   1487 
   1488 void VG_(gdbserver_status_output)(void)
   1489 {
   1490    const int nr_gdbserved_addresses
   1491       = (gs_addresses == NULL ? -1 : VG_(HT_count_nodes) (gs_addresses));
   1492    const int nr_watchpoints
   1493       = (gs_watches == NULL ? -1 : (int) VG_(sizeXA) (gs_watches));
   1494    remote_utils_output_status();
   1495    VG_(umsg)
   1496       ("nr of calls to gdbserver: %d\n"
   1497        "single stepping %d\n"
   1498        "interrupts intr_tid %d gs_non_busy %d gs_busy %d tid_non_intr %d\n"
   1499        "gdbserved addresses %d (-1 = not initialized)\n"
   1500        "watchpoints %d (-1 = not initialized)\n"
   1501        "vgdb-error %d\n"
   1502        "hostvisibility %s\n",
   1503        gdbserver_called,
   1504        valgrind_single_stepping(),
   1505 
   1506        vgdb_interrupted_tid,
   1507        interrupts_non_busy,
   1508        interrupts_while_busy,
   1509        interrupts_non_interruptible,
   1510 
   1511        nr_gdbserved_addresses,
   1512        nr_watchpoints,
   1513        VG_(dyn_vgdb_error),
   1514        hostvisibility ? "yes" : "no");
   1515 }
   1516