winsup/cygwin/debug.cc

   1 /* debug.cc
   2
   3 This software is a copyrighted work licensed under the terms of the
   4 Cygwin license.  Please consult the file "CYGWIN_LICENSE" for
   5 details. */
   6
   7 #include "winsup.h"
   8 #include "cygerrno.h"
   9 #ifdef DEBUGGING
  10 #include "path.h"
  11 #include "fhandler.h"
  12 #include "dtable.h"
  13 #include "cygheap.h"
  14 #endif
  15
  16 #undef CloseHandle
  17
  18 #ifdef DEBUGGING
  19 /* Here lies extra debugging routines which help track down internal
  20    Cygwin problems when compiled with -DDEBUGGING . */
  21 #define NFREEH (sizeof (cygheap->debug.freeh) / sizeof (cygheap->debug.freeh[0]))
  22
  23 class lock_debug
  24 {
  25   static NO_COPY SRWLOCK lock;
  26  public:
  27   lock_debug () { AcquireSRWLockExclusive (&lock); }
  28   ~lock_debug () { ReleaseSRWLockExclusive (&lock); }
  29 };
  30
  31 SRWLOCK NO_COPY lock_debug::lock = SRWLOCK_INIT;
  32
  33 static bool mark_closed (const char *, int, HANDLE, const char *, bool);
  34
  35 /* Find a registered handle in the linked list of handles. */
  36 static handle_list *
  37 find_handle (HANDLE h)
  38 {
  39   handle_list *hl;
  40   for (hl = &cygheap->debug.starth; hl->next != NULL; hl = hl->next)
  41     if (hl->next->h == h)
  42       goto out;
  43   hl = NULL;
  44
  45 out:
  46   return hl;
  47 }
  48
  49 void
  50 verify_handle (const char *func, int ln, HANDLE h)
  51 {
  52   lock_debug here;
  53   handle_list *hl = find_handle (h);
  54   if (!hl)
  55     return;
  56   system_printf ("%s:%d - multiple attempts to add handle %p", func, ln, h);
  57
  58   system_printf (" previously allocated by %s:%d(%s<%p>) winpid %d",
  59                  hl->func, hl->ln, hl->name, hl->h, hl->pid);
  60 }
  61
  62 void
  63 setclexec (HANDLE oh, HANDLE nh, bool not_inheriting)
  64 {
  65   lock_debug here;
  66   handle_list *hl = find_handle (oh);
  67   if (hl)
  68     {
  69       hl = hl->next;
  70       hl->inherited = !not_inheriting;
  71       hl->h = nh;
  72     }
  73 }
  74
  75 /* Create a new handle record */
  76 static handle_list *
  77 newh ()
  78 {
  79   handle_list *hl;
  80
  81   for (hl = cygheap->debug.freeh; hl < cygheap->debug.freeh + NFREEH; hl++)
  82     if (hl->name == NULL)
  83       return hl;
  84
  85   return NULL;
  86 }
  87
  88 void
  89 modify_handle (const char *func, int ln, HANDLE h, const char *name, bool inh)
  90 {
  91   lock_debug here;
  92   handle_list *hl = find_handle (h);
  93   if (!hl)
  94     {
  95       system_printf ("%s:%d handle %s<%p> not found", func, ln, name, h);
  96       return;
  97     }
  98   hl->next->inherited = inh;
  99   debug_printf ("%s:%d set handle %s<%p> inheritance flag to %d", func, ln,
 100                 name, h, inh);
 101 }
 102
 103 /* Add a handle to the linked list of known handles. */
 104 void
 105 add_handle (const char *func, int ln, HANDLE h, const char *name, bool inh)
 106 {
 107   handle_list *hl;
 108
 109   if (!cygheap)
 110     return;
 111
 112   lock_debug here;
 113   if ((hl = find_handle (h)))
 114     {
 115       hl = hl->next;
 116       if (hl->name == name && hl->func == func && hl->ln == ln)
 117         return;
 118       system_printf ("%s:%d - multiple attempts to add handle %s<%p>", func,
 119                      ln, name, h);
 120       system_printf (" previously allocated by %s:%d(%s<%p>) winpid %d",
 121                      hl->func, hl->ln, hl->name, hl->h, hl->pid);
 122       return;
 123     }
 124
 125   if ((hl = newh ()) == NULL)
 126     {
 127       debug_printf ("couldn't allocate memory for %s(%d): %s(%p)",
 128                     func, ln, name, h);
 129       return;
 130     }
 131   hl->h = h;
 132   hl->name = name;
 133   hl->func = func;
 134   hl->ln = ln;
 135   hl->inherited = inh;
 136   hl->pid = GetCurrentProcessId ();
 137   hl->next = cygheap->debug.starth.next;
 138   cygheap->debug.starth.next = hl;
 139   SetHandleInformation (h, HANDLE_FLAG_PROTECT_FROM_CLOSE, HANDLE_FLAG_PROTECT_FROM_CLOSE);
 140   debug_printf ("protecting handle '%s'(%p), inherited flag %d", hl->name, hl->h, hl->inherited);
 141 }
 142
 143 static void
 144 delete_handle (handle_list *hl)
 145 {
 146   handle_list *hnuke = hl->next;
 147   debug_printf ("nuking handle '%s' (%p)", hnuke->name, hnuke->h);
 148   hl->next = hnuke->next;
 149   memset (hnuke, 0, sizeof (*hnuke));
 150 }
 151
 152 void
 153 debug_fixup_after_fork_exec ()
 154 {
 155   /* No lock needed at this point */
 156   handle_list *hl;
 157   for (hl = &cygheap->debug.starth; hl->next != NULL; /* nothing */)
 158     if (hl->next->inherited)
 159       hl = hl->next;
 160     else
 161       delete_handle (hl);       // removes hl->next
 162 }
 163
 164 static bool
 165 mark_closed (const char *func, int ln, HANDLE h, const char *name, bool force)
 166 {
 167   handle_list *hl;
 168
 169   if (!cygheap)
 170     return true;
 171
 172   if ((hl = find_handle (h)) && !force)
 173     {
 174       hl = hl->next;
 175       system_printf ("attempt to close protected handle %s:%d(%s<%p>) winpid %d",
 176                      hl->func, hl->ln, hl->name, hl->h, hl->pid);
 177       system_printf (" by %s:%d(%s<%p>)", func, ln, name, h);
 178       return false;
 179     }
 180
 181   handle_list *hln;
 182   if (hl && (hln = hl->next) && strcmp (name, hln->name) != 0)
 183     {
 184       system_printf ("closing protected handle %s:%d(%s<%p>)",
 185                      hln->func, hln->ln, hln->name, hln->h);
 186       system_printf (" by %s:%d(%s<%p>)", func, ln, name, h);
 187     }
 188
 189   if (hl)
 190     delete_handle (hl);
 191
 192   return true;
 193 }
 194
 195 /* Close a known handle.  Complain if !force and closing a known handle or
 196    if the name of the handle being closed does not match the registered name. */
 197 bool
 198 close_handle (const char *func, int ln, HANDLE h, const char *name, bool force)
 199 {
 200   bool ret;
 201
 202   lock_debug here;
 203   if (!mark_closed (func, ln, h, name, force))
 204     return false;
 205
 206   SetHandleInformation (h, HANDLE_FLAG_PROTECT_FROM_CLOSE, 0);
 207   ret = CloseHandle (h);
 208
 209   if (!ret)
 210     {
 211       system_printf ("CloseHandle(%s<%p>) failed %s:%d, %E", name, h, func, ln);
 212       try_to_debug ();
 213     }
 214   return ret;
 215 }
 216 #endif /*DEBUGGING*/