m_libcproc.c revision c76d0e5cf15d9a352c39a72867ae1c41875c6bb0 
1
2/*--------------------------------------------------------------------*/
3/*--- Process-related libc stuff.                     m_libcproc.c ---*/
4/*--------------------------------------------------------------------*/
5
6/*
7   This file is part of Valgrind, a dynamic binary instrumentation
8   framework.
9
10   Copyright (C) 2000-2013 Julian Seward
11      jseward@acm.org
12
13   This program is free software; you can redistribute it and/or
14   modify it under the terms of the GNU General Public License as
15   published by the Free Software Foundation; either version 2 of the
16   License, or (at your option) any later version.
17
18   This program is distributed in the hope that it will be useful, but
19   WITHOUT ANY WARRANTY; without even the implied warranty of
20   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
21   General Public License for more details.
22
23   You should have received a copy of the GNU General Public License
24   along with this program; if not, write to the Free Software
25   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
26   02111-1307, USA.
27
28   The GNU General Public License is contained in the file COPYING.
29*/
30
31#include "pub_core_basics.h"
32#include "pub_core_machine.h"    // For VG_(machine_get_VexArchInfo)
33#include "pub_core_vki.h"
34#include "pub_core_vkiscnums.h"
35#include "pub_core_libcbase.h"
36#include "pub_core_libcassert.h"
37#include "pub_core_libcprint.h"
38#include "pub_core_libcproc.h"
39#include "pub_core_libcsignal.h"
40#include "pub_core_seqmatch.h"
41#include "pub_core_mallocfree.h"
42#include "pub_core_syscall.h"
43#include "pub_core_xarray.h"
44#include "pub_core_clientstate.h"
45
46#if defined(VGO_darwin)
47/* --- !!! --- EXTERNAL HEADERS start --- !!! --- */
48#include <mach/mach.h>   /* mach_thread_self */
49/* --- !!! --- EXTERNAL HEADERS end --- !!! --- */
50#endif
51
52/* IMPORTANT: on Darwin it is essential to use the _nocancel versions
53   of syscalls rather than the vanilla version, if a _nocancel version
54   is available.  See docs/internals/Darwin-notes.txt for the reason
55   why. */
56
57/* ---------------------------------------------------------------------
58   Command line and environment stuff
59   ------------------------------------------------------------------ */
60
61/* As deduced from sp_at_startup, the client's argc, argv[] and
62   envp[] as extracted from the client's stack at startup-time. */
63HChar** VG_(client_envp) = NULL;
64
65/* Path to library directory */
66const HChar *VG_(libdir) = VG_LIBDIR;
67
68const HChar *VG_(LD_PRELOAD_var_name) =
69#if defined(VGO_linux)
70   "LD_PRELOAD";
71#elif defined(VGO_darwin)
72   "DYLD_INSERT_LIBRARIES";
73#else
74#  error Unknown OS
75#endif
76
77/* We do getenv without libc's help by snooping around in
78   VG_(client_envp) as determined at startup time. */
79HChar *VG_(getenv)(const HChar *varname)
80{
81   Int i, n;
82   vg_assert( VG_(client_envp) );
83   n = VG_(strlen)(varname);
84   for (i = 0; VG_(client_envp)[i] != NULL; i++) {
85      HChar* s = VG_(client_envp)[i];
86      if (VG_(strncmp)(varname, s, n) == 0 && s[n] == '=') {
87         return & s[n+1];
88      }
89   }
90   return NULL;
91}
92
93void  VG_(env_unsetenv) ( HChar **env, const HChar *varname )
94{
95   HChar **from, **to;
96   vg_assert(env);
97   vg_assert(varname);
98   to = NULL;
99   Int len = VG_(strlen)(varname);
100
101   for (from = to = env; from && *from; from++) {
102      if (!(VG_(strncmp)(varname, *from, len) == 0 && (*from)[len] == '=')) {
103	 *to = *from;
104	 to++;
105      }
106   }
107   *to = *from;
108}
109
110/* set the environment; returns the old env if a new one was allocated */
111HChar **VG_(env_setenv) ( HChar ***envp, const HChar* varname,
112                          const HChar *val )
113{
114   HChar **env = (*envp);
115   HChar **cpp;
116   Int len = VG_(strlen)(varname);
117   HChar *valstr = VG_(arena_malloc)(VG_AR_CORE, "libcproc.es.1",
118                                     len + VG_(strlen)(val) + 2);
119   HChar **oldenv = NULL;
120
121   VG_(sprintf)(valstr, "%s=%s", varname, val);
122
123   for (cpp = env; cpp && *cpp; cpp++) {
124      if (VG_(strncmp)(varname, *cpp, len) == 0 && (*cpp)[len] == '=') {
125	 *cpp = valstr;
126	 return oldenv;
127      }
128   }
129
130   if (env == NULL) {
131      env = VG_(arena_malloc)(VG_AR_CORE, "libcproc.es.2", sizeof(HChar *) * 2);
132      env[0] = valstr;
133      env[1] = NULL;
134
135      *envp = env;
136
137   }  else {
138      Int envlen = (cpp-env) + 2;
139      HChar **newenv = VG_(arena_malloc)(VG_AR_CORE, "libcproc.es.3",
140                                         envlen * sizeof(HChar *));
141
142      for (cpp = newenv; *env; )
143	 *cpp++ = *env++;
144      *cpp++ = valstr;
145      *cpp++ = NULL;
146
147      oldenv = *envp;
148
149      *envp = newenv;
150   }
151
152   return oldenv;
153}
154
155
156/* Walk through a colon-separated environment variable, and remove the
157   entries which match remove_pattern.  It slides everything down over
158   the removed entries, and pads the remaining space with '\0'.  It
159   modifies the entries in place (in the client address space), but it
160   shouldn't matter too much, since we only do this just before an
161   execve().
162
163   This is also careful to mop up any excess ':'s, since empty strings
164   delimited by ':' are considered to be '.' in a path.
165*/
166static void mash_colon_env(HChar *varp, const HChar *remove_pattern)
167{
168   HChar *const start = varp;
169   HChar *entry_start = varp;
170   HChar *output = varp;
171
172   if (varp == NULL)
173      return;
174
175   while(*varp) {
176      if (*varp == ':') {
177	 HChar prev;
178	 Bool match;
179
180	 /* This is a bit subtle: we want to match against the entry
181	    we just copied, because it may have overlapped with
182	    itself, junking the original. */
183
184	 prev = *output;
185	 *output = '\0';
186
187	 match = VG_(string_match)(remove_pattern, entry_start);
188
189	 *output = prev;
190
191	 if (match) {
192	    output = entry_start;
193	    varp++;			/* skip ':' after removed entry */
194	 } else
195	    entry_start = output+1;	/* entry starts after ':' */
196      }
197
198      if (*varp)
199         *output++ = *varp++;
200   }
201
202   /* make sure last entry is nul terminated */
203   *output = '\0';
204
205   /* match against the last entry */
206   if (VG_(string_match)(remove_pattern, entry_start)) {
207      output = entry_start;
208      if (output > start) {
209	 /* remove trailing ':' */
210	 output--;
211	 vg_assert(*output == ':');
212      }
213   }
214
215   /* pad out the left-overs with '\0' */
216   while(output < varp)
217      *output++ = '\0';
218}
219
220
221// Removes all the Valgrind-added stuff from the passed environment.  Used
222// when starting child processes, so they don't see that added stuff.
223void VG_(env_remove_valgrind_env_stuff)(HChar** envp)
224{
225
226#if defined(VGO_darwin)
227
228   // Environment cleanup is also handled during parent launch
229   // in vg_preloaded.c:vg_cleanup_env().
230
231#endif
232
233   Int i;
234   HChar* ld_preload_str = NULL;
235   HChar* ld_library_path_str = NULL;
236   HChar* dyld_insert_libraries_str = NULL;
237   HChar* buf;
238
239   // Find LD_* variables
240   // DDD: should probably conditionally compiled some of this:
241   // - LD_LIBRARY_PATH is universal?
242   // - LD_PRELOAD is on Linux, not on Darwin, not sure about AIX
243   // - DYLD_INSERT_LIBRARIES and DYLD_SHARED_REGION are Darwin-only
244   for (i = 0; envp[i] != NULL; i++) {
245      if (VG_(strncmp)(envp[i], "LD_PRELOAD=", 11) == 0) {
246         envp[i] = VG_(arena_strdup)(VG_AR_CORE, "libcproc.erves.1", envp[i]);
247         ld_preload_str = &envp[i][11];
248      }
249      if (VG_(strncmp)(envp[i], "LD_LIBRARY_PATH=", 16) == 0) {
250         envp[i] = VG_(arena_strdup)(VG_AR_CORE, "libcproc.erves.2", envp[i]);
251         ld_library_path_str = &envp[i][16];
252      }
253      if (VG_(strncmp)(envp[i], "DYLD_INSERT_LIBRARIES=", 22) == 0) {
254         envp[i] = VG_(arena_strdup)(VG_AR_CORE, "libcproc.erves.3", envp[i]);
255         dyld_insert_libraries_str = &envp[i][22];
256      }
257   }
258
259   buf = VG_(arena_malloc)(VG_AR_CORE, "libcproc.erves.4",
260                           VG_(strlen)(VG_(libdir)) + 20);
261
262   // Remove Valgrind-specific entries from LD_*.
263   VG_(sprintf)(buf, "%s*/vgpreload_*.so", VG_(libdir));
264   mash_colon_env(ld_preload_str, buf);
265   mash_colon_env(dyld_insert_libraries_str, buf);
266   VG_(sprintf)(buf, "%s*", VG_(libdir));
267   mash_colon_env(ld_library_path_str, buf);
268
269   // Remove VALGRIND_LAUNCHER variable.
270   VG_(env_unsetenv)(envp, VALGRIND_LAUNCHER);
271
272   // Remove DYLD_SHARED_REGION variable.
273   VG_(env_unsetenv)(envp, "DYLD_SHARED_REGION");
274
275   // XXX if variable becomes empty, remove it completely?
276
277   VG_(arena_free)(VG_AR_CORE, buf);
278}
279
280/* ---------------------------------------------------------------------
281   Various important syscall wrappers
282   ------------------------------------------------------------------ */
283
284Int VG_(waitpid)(Int pid, Int *status, Int options)
285{
286#  if defined(VGO_linux)
287   SysRes res = VG_(do_syscall4)(__NR_wait4,
288                                 pid, (UWord)status, options, 0);
289   return sr_isError(res) ? -1 : sr_Res(res);
290#  elif defined(VGO_darwin)
291   SysRes res = VG_(do_syscall4)(__NR_wait4_nocancel,
292                                 pid, (UWord)status, options, 0);
293   return sr_isError(res) ? -1 : sr_Res(res);
294#  else
295#    error Unknown OS
296#  endif
297}
298
299/* clone the environment */
300HChar **VG_(env_clone) ( HChar **oldenv )
301{
302   HChar **oldenvp;
303   HChar **newenvp;
304   HChar **newenv;
305   Int  envlen;
306
307   vg_assert(oldenv);
308   for (oldenvp = oldenv; oldenvp && *oldenvp; oldenvp++);
309
310   envlen = oldenvp - oldenv + 1;
311
312   newenv = VG_(arena_malloc)(VG_AR_CORE, "libcproc.ec.1",
313                              envlen * sizeof(HChar *));
314
315   oldenvp = oldenv;
316   newenvp = newenv;
317
318   while (oldenvp && *oldenvp) {
319      *newenvp++ = *oldenvp++;
320   }
321
322   *newenvp = *oldenvp;
323
324   return newenv;
325}
326
327void VG_(execv) ( const HChar* filename, HChar** argv )
328{
329   HChar** envp;
330   SysRes res;
331
332   /* restore the DATA rlimit for the child */
333   VG_(setrlimit)(VKI_RLIMIT_DATA, &VG_(client_rlimit_data));
334
335   envp = VG_(env_clone)(VG_(client_envp));
336   VG_(env_remove_valgrind_env_stuff)( envp );
337
338   res = VG_(do_syscall3)(__NR_execve,
339                          (UWord)filename, (UWord)argv, (UWord)envp);
340
341   VG_(printf)("EXEC failed, errno = %lld\n", (Long)sr_Err(res));
342}
343
344/* Return -1 if error, else 0.  NOTE does not indicate return code of
345   child! */
346Int VG_(system) ( const HChar* cmd )
347{
348   Int pid;
349   if (cmd == NULL)
350      return 1;
351   pid = VG_(fork)();
352   if (pid < 0)
353      return -1;
354   if (pid == 0) {
355      /* child */
356      const HChar* argv[4] = { "/bin/sh", "-c", cmd, 0 };
357      VG_(execv)(argv[0], (HChar **)argv);
358
359      /* If we're still alive here, execv failed. */
360      VG_(exit)(1);
361   } else {
362      /* parent */
363      /* We have to set SIGCHLD to its default behaviour in order that
364         VG_(waitpid) works (at least on AIX).  According to the Linux
365         man page for waitpid:
366
367         POSIX.1-2001 specifies that if the disposition of SIGCHLD is
368         set to SIG_IGN or the SA_NOCLDWAIT flag is set for SIGCHLD
369         (see sigaction(2)), then children that terminate do not
370         become zombies and a call to wait() or waitpid() will block
371         until all children have terminated, and then fail with errno
372         set to ECHILD.  (The original POSIX standard left the
373         behaviour of setting SIGCHLD to SIG_IGN unspecified.)
374      */
375      Int ir, zzz;
376      vki_sigaction_toK_t sa, sa2;
377      vki_sigaction_fromK_t saved_sa;
378      VG_(memset)( &sa, 0, sizeof(sa) );
379      VG_(sigemptyset)(&sa.sa_mask);
380      sa.ksa_handler = VKI_SIG_DFL;
381      sa.sa_flags    = 0;
382      ir = VG_(sigaction)(VKI_SIGCHLD, &sa, &saved_sa);
383      vg_assert(ir == 0);
384
385      zzz = VG_(waitpid)(pid, NULL, 0);
386
387      VG_(convert_sigaction_fromK_to_toK)( &saved_sa, &sa2 );
388      ir = VG_(sigaction)(VKI_SIGCHLD, &sa2, NULL);
389      vg_assert(ir == 0);
390      return zzz == -1 ? -1 : 0;
391   }
392}
393
394/* ---------------------------------------------------------------------
395   Resource limits
396   ------------------------------------------------------------------ */
397
398/* Support for getrlimit. */
399Int VG_(getrlimit) (Int resource, struct vki_rlimit *rlim)
400{
401   SysRes res = VG_(mk_SysRes_Error)(VKI_ENOSYS);
402   /* res = getrlimit( resource, rlim ); */
403#  ifdef __NR_ugetrlimit
404   res = VG_(do_syscall2)(__NR_ugetrlimit, resource, (UWord)rlim);
405#  endif
406   if (sr_isError(res) && sr_Err(res) == VKI_ENOSYS)
407      res = VG_(do_syscall2)(__NR_getrlimit, resource, (UWord)rlim);
408   return sr_isError(res) ? -1 : sr_Res(res);
409}
410
411
412/* Support for setrlimit. */
413Int VG_(setrlimit) (Int resource, const struct vki_rlimit *rlim)
414{
415   SysRes res;
416   /* res = setrlimit( resource, rlim ); */
417   res = VG_(do_syscall2)(__NR_setrlimit, resource, (UWord)rlim);
418   return sr_isError(res) ? -1 : sr_Res(res);
419}
420
421/* Support for prctl. */
422Int VG_(prctl) (Int option,
423                ULong arg2, ULong arg3, ULong arg4, ULong arg5)
424{
425   SysRes res = VG_(mk_SysRes_Error)(VKI_ENOSYS);
426#  if defined(VGO_linux)
427   /* res = prctl( option, arg2, arg3, arg4, arg5 ); */
428   res = VG_(do_syscall5)(__NR_prctl, (UWord) option,
429                          (UWord) arg2, (UWord) arg3, (UWord) arg4,
430                          (UWord) arg5);
431#  endif
432
433   return sr_isError(res) ? -1 : sr_Res(res);
434}
435
436/* ---------------------------------------------------------------------
437   pids, etc
438   ------------------------------------------------------------------ */
439
440Int VG_(gettid)(void)
441{
442#  if defined(VGO_linux)
443   SysRes res = VG_(do_syscall0)(__NR_gettid);
444
445   if (sr_isError(res) && sr_Res(res) == VKI_ENOSYS) {
446      HChar pid[16];
447      /*
448       * The gettid system call does not exist. The obvious assumption
449       * to make at this point would be that we are running on an older
450       * system where the getpid system call actually returns the ID of
451       * the current thread.
452       *
453       * Unfortunately it seems that there are some systems with a kernel
454       * where getpid has been changed to return the ID of the thread group
455       * leader but where the gettid system call has not yet been added.
456       *
457       * So instead of calling getpid here we use readlink to see where
458       * the /proc/self link is pointing...
459       */
460
461#     if defined(VGP_arm64_linux)
462      res = VG_(do_syscall4)(__NR_readlinkat, VKI_AT_FDCWD,
463                             (UWord)"/proc/self",
464                             (UWord)pid, sizeof(pid));
465#     else
466      res = VG_(do_syscall3)(__NR_readlink, (UWord)"/proc/self",
467                             (UWord)pid, sizeof(pid));
468#     endif
469      if (!sr_isError(res) && sr_Res(res) > 0) {
470         HChar* s;
471         pid[sr_Res(res)] = '\0';
472         res = VG_(mk_SysRes_Success)(  VG_(strtoll10)(pid, &s) );
473         if (*s != '\0') {
474            VG_(message)(Vg_DebugMsg,
475               "Warning: invalid file name linked to by /proc/self: %s\n",
476               pid);
477         }
478      }
479   }
480
481   return sr_Res(res);
482
483#  elif defined(VGO_darwin)
484   // Darwin's gettid syscall is something else.
485   // Use Mach thread ports for lwpid instead.
486   return mach_thread_self();
487
488#  else
489#    error "Unknown OS"
490#  endif
491}
492
493/* You'd be amazed how many places need to know the current pid. */
494Int VG_(getpid) ( void )
495{
496   /* ASSUMES SYSCALL ALWAYS SUCCEEDS */
497   return sr_Res( VG_(do_syscall0)(__NR_getpid) );
498}
499
500Int VG_(getpgrp) ( void )
501{
502   /* ASSUMES SYSCALL ALWAYS SUCCEEDS */
503   return sr_Res( VG_(do_syscall0)(__NR_getpgrp) );
504}
505
506Int VG_(getppid) ( void )
507{
508   /* ASSUMES SYSCALL ALWAYS SUCCEEDS */
509   return sr_Res( VG_(do_syscall0)(__NR_getppid) );
510}
511
512Int VG_(geteuid) ( void )
513{
514   /* ASSUMES SYSCALL ALWAYS SUCCEEDS */
515#  if defined(__NR_geteuid32)
516   // We use the 32-bit version if it's supported.  Otherwise, IDs greater
517   // than 65536 cause problems, as bug #151209 showed.
518   return sr_Res( VG_(do_syscall0)(__NR_geteuid32) );
519#  else
520   return sr_Res( VG_(do_syscall0)(__NR_geteuid) );
521#  endif
522}
523
524Int VG_(getegid) ( void )
525{
526   /* ASSUMES SYSCALL ALWAYS SUCCEEDS */
527#  if defined(__NR_getegid32)
528   // We use the 32-bit version if it's supported.  Otherwise, IDs greater
529   // than 65536 cause problems, as bug #151209 showed.
530   return sr_Res( VG_(do_syscall0)(__NR_getegid32) );
531#  else
532   return sr_Res( VG_(do_syscall0)(__NR_getegid) );
533#  endif
534}
535
536/* Get supplementary groups into list[0 .. size-1].  Returns the
537   number of groups written, or -1 if error.  Note that in order to be
538   portable, the groups are 32-bit unsigned ints regardless of the
539   platform. */
540Int VG_(getgroups)( Int size, UInt* list )
541{
542#  if defined(VGP_x86_linux) || defined(VGP_ppc32_linux) \
543      || defined(VGP_mips64_linux)
544   Int    i;
545   SysRes sres;
546   UShort list16[64];
547   if (size < 0) return -1;
548   if (size > 64) size = 64;
549   sres = VG_(do_syscall2)(__NR_getgroups, size, (Addr)list16);
550   if (sr_isError(sres))
551      return -1;
552   if (sr_Res(sres) > size)
553      return -1;
554   for (i = 0; i < sr_Res(sres); i++)
555      list[i] = (UInt)list16[i];
556   return sr_Res(sres);
557
558#  elif defined(VGP_amd64_linux) || defined(VGP_ppc64_linux)  \
559        || defined(VGP_arm_linux)                             \
560        || defined(VGO_darwin) || defined(VGP_s390x_linux)    \
561        || defined(VGP_mips32_linux) || defined(VGP_arm64_linux)
562   SysRes sres;
563   sres = VG_(do_syscall2)(__NR_getgroups, size, (Addr)list);
564   if (sr_isError(sres))
565      return -1;
566   return sr_Res(sres);
567
568#  else
569#     error "VG_(getgroups): needs implementation on this platform"
570#  endif
571}
572
573/* ---------------------------------------------------------------------
574   Process tracing
575   ------------------------------------------------------------------ */
576
577Int VG_(ptrace) ( Int request, Int pid, void *addr, void *data )
578{
579   SysRes res;
580   res = VG_(do_syscall4)(__NR_ptrace, request, pid, (UWord)addr, (UWord)data);
581   if (sr_isError(res))
582      return -1;
583   return sr_Res(res);
584}
585
586/* ---------------------------------------------------------------------
587   Fork
588   ------------------------------------------------------------------ */
589
590Int VG_(fork) ( void )
591{
592#  if defined(VGO_linux)
593   SysRes res;
594   res = VG_(do_syscall0)(__NR_fork);
595   if (sr_isError(res))
596      return -1;
597   return sr_Res(res);
598
599#  elif defined(VGO_darwin)
600   SysRes res;
601   res = VG_(do_syscall0)(__NR_fork); /* __NR_fork is UX64 */
602   if (sr_isError(res))
603      return -1;
604   /* on success: wLO = child pid; wHI = 1 for child, 0 for parent */
605   if (sr_ResHI(res) != 0) {
606      return 0;  /* this is child: return 0 instead of child pid */
607   }
608   return sr_Res(res);
609
610#  else
611#    error "Unknown OS"
612#  endif
613}
614
615/* ---------------------------------------------------------------------
616   Timing stuff
617   ------------------------------------------------------------------ */
618
619UInt VG_(read_millisecond_timer) ( void )
620{
621   /* 'now' and 'base' are in microseconds */
622   static ULong base = 0;
623   ULong  now;
624
625#  if defined(VGO_linux)
626   { SysRes res;
627     struct vki_timespec ts_now;
628     res = VG_(do_syscall2)(__NR_clock_gettime, VKI_CLOCK_MONOTONIC,
629                            (UWord)&ts_now);
630     if (sr_isError(res) == 0) {
631        now = ts_now.tv_sec * 1000000ULL + ts_now.tv_nsec / 1000;
632     } else {
633       struct vki_timeval tv_now;
634       res = VG_(do_syscall2)(__NR_gettimeofday, (UWord)&tv_now, (UWord)NULL);
635       vg_assert(! sr_isError(res));
636       now = tv_now.tv_sec * 1000000ULL + tv_now.tv_usec;
637     }
638   }
639
640#  elif defined(VGO_darwin)
641   // Weird: it seems that gettimeofday() doesn't fill in the timeval, but
642   // rather returns the tv_sec as the low 32 bits of the result and the
643   // tv_usec as the high 32 bits of the result.  (But the timeval cannot be
644   // NULL!)  See bug 200990.
645   { SysRes res;
646     struct vki_timeval tv_now = { 0, 0 };
647     res = VG_(do_syscall2)(__NR_gettimeofday, (UWord)&tv_now, (UWord)NULL);
648     vg_assert(! sr_isError(res));
649     now = sr_Res(res) * 1000000ULL + sr_ResHI(res);
650   }
651
652#  else
653#    error "Unknown OS"
654#  endif
655
656   /* COMMON CODE */
657   if (base == 0)
658      base = now;
659
660   return (now - base) / 1000;
661}
662
663
664/* ---------------------------------------------------------------------
665   atfork()
666   ------------------------------------------------------------------ */
667
668struct atfork {
669   vg_atfork_t  pre;
670   vg_atfork_t  parent;
671   vg_atfork_t  child;
672};
673
674#define VG_MAX_ATFORK 10
675
676static struct atfork atforks[VG_MAX_ATFORK];
677static Int n_atfork = 0;
678
679void VG_(atfork)(vg_atfork_t pre, vg_atfork_t parent, vg_atfork_t child)
680{
681   Int i;
682
683   for (i = 0; i < n_atfork; i++) {
684      if (atforks[i].pre == pre &&
685          atforks[i].parent == parent &&
686          atforks[i].child == child)
687         return;
688   }
689
690   if (n_atfork >= VG_MAX_ATFORK)
691      VG_(core_panic)(
692         "Too many VG_(atfork) handlers requested: raise VG_MAX_ATFORK");
693
694   atforks[n_atfork].pre    = pre;
695   atforks[n_atfork].parent = parent;
696   atforks[n_atfork].child  = child;
697
698   n_atfork++;
699}
700
701void VG_(do_atfork_pre)(ThreadId tid)
702{
703   Int i;
704
705   for (i = 0; i < n_atfork; i++)
706      if (atforks[i].pre != NULL)
707         (*atforks[i].pre)(tid);
708}
709
710void VG_(do_atfork_parent)(ThreadId tid)
711{
712   Int i;
713
714   for (i = 0; i < n_atfork; i++)
715      if (atforks[i].parent != NULL)
716         (*atforks[i].parent)(tid);
717}
718
719void VG_(do_atfork_child)(ThreadId tid)
720{
721   Int i;
722
723   for (i = 0; i < n_atfork; i++)
724      if (atforks[i].child != NULL)
725         (*atforks[i].child)(tid);
726}
727
728
729/* ---------------------------------------------------------------------
730   icache invalidation
731   ------------------------------------------------------------------ */
732
733void VG_(invalidate_icache) ( void *ptr, SizeT nbytes )
734{
735   if (nbytes == 0) return;    // nothing to do
736
737   // Get cache info
738   VexArchInfo vai;
739   VG_(machine_get_VexArchInfo)(NULL, &vai);
740
741   // If I-caches are coherent, nothing needs to be done here
742   if (vai.hwcache_info.icaches_maintain_coherence) return;
743
744#  if defined(VGA_ppc32) || defined(VGA_ppc64)
745   Addr startaddr = (Addr) ptr;
746   Addr endaddr   = startaddr + nbytes;
747   Addr cls;
748   Addr addr;
749
750   VG_(machine_get_VexArchInfo)( NULL, &vai );
751   cls = vai.ppc_icache_line_szB;
752
753   /* Stay sane .. */
754   vg_assert(cls == 16 || cls == 32 || cls == 64 || cls == 128);
755
756   startaddr &= ~(cls - 1);
757   for (addr = startaddr; addr < endaddr; addr += cls) {
758      __asm__ __volatile__("dcbst 0,%0" : : "r" (addr));
759   }
760   __asm__ __volatile__("sync");
761   for (addr = startaddr; addr < endaddr; addr += cls) {
762      __asm__ __volatile__("icbi 0,%0" : : "r" (addr));
763   }
764   __asm__ __volatile__("sync; isync");
765
766#  elif defined(VGP_arm_linux)
767   /* ARM cache flushes are privileged, so we must defer to the kernel. */
768   Addr startaddr = (Addr) ptr;
769   Addr endaddr   = startaddr + nbytes;
770   VG_(do_syscall2)(__NR_ARM_cacheflush, startaddr, endaddr);
771
772#  elif defined(VGP_arm64_linux)
773   // This arm64_linux section of this function VG_(invalidate_icache)
774   // is copied from
775   // https://github.com/armvixl/vixl/blob/master/src/a64/cpu-a64.cc
776   // which has the following copyright notice:
777   /*
778   Copyright 2013, ARM Limited
779   All rights reserved.
780
781   Redistribution and use in source and binary forms, with or without
782   modification, are permitted provided that the following conditions are met:
783
784   * Redistributions of source code must retain the above copyright notice,
785     this list of conditions and the following disclaimer.
786   * Redistributions in binary form must reproduce the above copyright notice,
787     this list of conditions and the following disclaimer in the documentation
788     and/or other materials provided with the distribution.
789   * Neither the name of ARM Limited nor the names of its contributors may be
790     used to endorse or promote products derived from this software without
791     specific prior written permission.
792
793   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS CONTRIBUTORS "AS IS" AND
794   ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
795   WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
796   DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE
797   FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
798   DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
799   SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
800   CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
801   OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
802   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
803   */
804
805   // Ask what the I and D line sizes are
806   UInt cache_type_register;
807   // Copy the content of the cache type register to a core register.
808   __asm__ __volatile__ ("mrs %[ctr], ctr_el0" // NOLINT
809                         : [ctr] "=r" (cache_type_register));
810
811   const Int kDCacheLineSizeShift = 16;
812   const Int kICacheLineSizeShift = 0;
813   const UInt kDCacheLineSizeMask = 0xf << kDCacheLineSizeShift;
814   const UInt kICacheLineSizeMask = 0xf << kICacheLineSizeShift;
815
816   // The cache type register holds the size of the I and D caches as a power of
817   // two.
818   const UInt dcache_line_size_power_of_two =
819       (cache_type_register & kDCacheLineSizeMask) >> kDCacheLineSizeShift;
820   const UInt icache_line_size_power_of_two =
821       (cache_type_register & kICacheLineSizeMask) >> kICacheLineSizeShift;
822
823   const UInt dcache_line_size_ = 1 << dcache_line_size_power_of_two;
824   const UInt icache_line_size_ = 1 << icache_line_size_power_of_two;
825
826   Addr start = (Addr)ptr;
827   // Sizes will be used to generate a mask big enough to cover a pointer.
828   Addr dsize = (Addr)dcache_line_size_;
829   Addr isize = (Addr)icache_line_size_;
830
831   // Cache line sizes are always a power of 2.
832   Addr dstart = start & ~(dsize - 1);
833   Addr istart = start & ~(isize - 1);
834   Addr end    = start + nbytes;
835
836   __asm__ __volatile__ (
837     // Clean every line of the D cache containing the target data.
838     "0: \n\t"
839     // dc : Data Cache maintenance
840     // c : Clean
841     // va : by (Virtual) Address
842     // u : to the point of Unification
843     // The point of unification for a processor is the point by which the
844     // instruction and data caches are guaranteed to see the same copy of a
845     // memory location. See ARM DDI 0406B page B2-12 for more information.
846     "dc cvau, %[dline] \n\t"
847     "add %[dline], %[dline], %[dsize] \n\t"
848     "cmp %[dline], %[end] \n\t"
849     "b.lt 0b \n\t"
850     // Barrier to make sure the effect of the code above is visible to the rest
851     // of the world.
852     // dsb : Data Synchronisation Barrier
853     // ish : Inner SHareable domain
854     // The point of unification for an Inner Shareable shareability domain is
855     // the point by which the instruction and data caches of all the processors
856     // in that Inner Shareable shareability domain are guaranteed to see the
857     // same copy of a memory location. See ARM DDI 0406B page B2-12 for more
858     // information.
859     "dsb ish \n\t"
860     // Invalidate every line of the I cache containing the target data.
861     "1: \n\t"
862     // ic : instruction cache maintenance
863     // i : invalidate
864     // va : by address
865     // u : to the point of unification
866     "ic ivau, %[iline] \n\t"
867     "add %[iline], %[iline], %[isize] \n\t"
868     "cmp %[iline], %[end] \n\t"
869     "b.lt 1b \n\t"
870     // Barrier to make sure the effect of the code above is visible to the rest
871     // of the world.
872     "dsb ish \n\t"
873     // Barrier to ensure any prefetching which happened before this code is
874     // discarded.
875     // isb : Instruction Synchronisation Barrier
876     "isb \n\t"
877     : [dline] "+r" (dstart),
878       [iline] "+r" (istart)
879     : [dsize] "r" (dsize),
880       [isize] "r" (isize),
881       [end] "r" (end)
882     // This code does not write to memory but without the dependency gcc might
883     // move this code before the code is generated.
884     : "cc", "memory"
885   );
886
887#  elif defined(VGA_mips32) || defined(VGA_mips64)
888   SysRes sres = VG_(do_syscall3)(__NR_cacheflush, (UWord) ptr,
889                                 (UWord) nbytes, (UWord) 3);
890   vg_assert( sres._isError == 0 );
891
892#  endif
893}
894
895
896/* ---------------------------------------------------------------------
897   dcache flushing
898   ------------------------------------------------------------------ */
899
900void VG_(flush_dcache) ( void *ptr, SizeT nbytes )
901{
902   /* Currently this is only required on ARM64. */
903#  if defined(VGA_arm64)
904   Addr startaddr = (Addr) ptr;
905   Addr endaddr   = startaddr + nbytes;
906   Addr cls;
907   Addr addr;
908
909   ULong ctr_el0;
910   __asm__ __volatile__ ("mrs %0, ctr_el0" : "=r"(ctr_el0));
911   cls = 4 * (1ULL << (0xF & (ctr_el0 >> 16)));
912
913   /* Stay sane .. */
914   vg_assert(cls == 64);
915
916   startaddr &= ~(cls - 1);
917   for (addr = startaddr; addr < endaddr; addr += cls) {
918      __asm__ __volatile__("dc cvau, %0" : : "r" (addr));
919   }
920   __asm__ __volatile__("dsb ish");
921#  endif
922}
923
924/*--------------------------------------------------------------------*/
925/*--- end                                                          ---*/
926/*--------------------------------------------------------------------*/
927