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1 : : /* Memory handling for libdw. 2 : : Copyright (C) 2003, 2004, 2006 Red Hat, Inc. 3 : : This file is part of elfutils. 4 : : Written by Ulrich Drepper <drepper@redhat.com>, 2003. 5 : : 6 : : This file is free software; you can redistribute it and/or modify 7 : : it under the terms of either 8 : : 9 : : * the GNU Lesser General Public License as published by the Free 10 : : Software Foundation; either version 3 of the License, or (at 11 : : your option) any later version 12 : : 13 : : or 14 : : 15 : : * the GNU General Public License as published by the Free 16 : : Software Foundation; either version 2 of the License, or (at 17 : : your option) any later version 18 : : 19 : : or both in parallel, as here. 20 : : 21 : : elfutils is distributed in the hope that it will be useful, but 22 : : WITHOUT ANY WARRANTY; without even the implied warranty of 23 : : MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 24 : : General Public License for more details. 25 : : 26 : : You should have received copies of the GNU General Public License and 27 : : the GNU Lesser General Public License along with this program. If 28 : : not, see <http://www.gnu.org/licenses/>. */ 29 : : 30 : : #ifdef HAVE_CONFIG_H 31 : : # include <config.h> 32 : : #endif 33 : : 34 : : #include <errno.h> 35 : : #include <stdlib.h> 36 : : #include "libdwP.h" 37 : : #include "system.h" 38 : : #include "atomics.h" 39 : : #if USE_VG_ANNOTATIONS == 1 40 : : #include <helgrind.h> 41 : : #else 42 : : #define ANNOTATE_HAPPENS_BEFORE(X) 43 : : #define ANNOTATE_HAPPENS_AFTER(X) 44 : : #endif 45 : : 46 : : #define THREAD_ID_UNSET ((size_t) -1) 47 : : static __thread size_t thread_id = THREAD_ID_UNSET; 48 : : static atomic_size_t next_id = ATOMIC_VAR_INIT(0); 49 : : 50 : : struct libdw_memblock * 51 : 5332436 : __libdw_alloc_tail (Dwarf *dbg) 52 : : { 53 [ + + ]: 5332436 : if (thread_id == THREAD_ID_UNSET) 54 : 1037 : thread_id = atomic_fetch_add (&next_id, 1); 55 : : 56 : 5332436 : pthread_rwlock_rdlock (&dbg->mem_rwl); 57 [ + + ]: 5332436 : if (thread_id >= dbg->mem_stacks) 58 : : { 59 : 1454 : pthread_rwlock_unlock (&dbg->mem_rwl); 60 : 1454 : pthread_rwlock_wrlock (&dbg->mem_rwl); 61 : : 62 : : /* Another thread may have already reallocated. In theory using an 63 : : atomic would be faster, but given that this only happens once per 64 : : thread per Dwarf, some minor slowdown should be fine. */ 65 [ + - ]: 1454 : if (thread_id >= dbg->mem_stacks) 66 : : { 67 : 1454 : dbg->mem_tails = realloc (dbg->mem_tails, (thread_id+1) 68 : : * sizeof (struct libdw_memblock *)); 69 [ - + ]: 1454 : if (dbg->mem_tails == NULL) 70 : : { 71 : 0 : pthread_rwlock_unlock (&dbg->mem_rwl); 72 : 0 : dbg->oom_handler(); 73 : : } 74 [ + + ]: 3095 : for (size_t i = dbg->mem_stacks; i <= thread_id; i++) 75 : 1641 : dbg->mem_tails[i] = NULL; 76 : 1454 : dbg->mem_stacks = thread_id + 1; 77 : 1454 : ANNOTATE_HAPPENS_BEFORE (&dbg->mem_tails); 78 : : } 79 : : 80 : 1454 : pthread_rwlock_unlock (&dbg->mem_rwl); 81 : 1454 : pthread_rwlock_rdlock (&dbg->mem_rwl); 82 : : } 83 : : 84 : : /* At this point, we have an entry in the tail array. */ 85 : 5332436 : ANNOTATE_HAPPENS_AFTER (&dbg->mem_tails); 86 : 5332436 : struct libdw_memblock *result = dbg->mem_tails[thread_id]; 87 [ + + ]: 5332436 : if (result == NULL) 88 : : { 89 : 1454 : result = malloc (dbg->mem_default_size); 90 [ - + ]: 1454 : if (result == NULL) 91 : : { 92 : 0 : pthread_rwlock_unlock (&dbg->mem_rwl); 93 : 0 : dbg->oom_handler(); 94 : : } 95 : 1454 : result->size = dbg->mem_default_size 96 : 1454 : - offsetof (struct libdw_memblock, mem); 97 : 1454 : result->remaining = result->size; 98 : 1454 : result->prev = NULL; 99 : 1454 : dbg->mem_tails[thread_id] = result; 100 : : } 101 : 5332436 : pthread_rwlock_unlock (&dbg->mem_rwl); 102 : 5332436 : return result; 103 : : } 104 : : 105 : : /* Can only be called after a allocation for this thread has already 106 : : been done, to possibly undo it. */ 107 : : struct libdw_memblock * 108 : 0 : __libdw_thread_tail (Dwarf *dbg) 109 : : { 110 : 0 : struct libdw_memblock *result; 111 : 0 : pthread_rwlock_rdlock (&dbg->mem_rwl); 112 : 0 : result = dbg->mem_tails[thread_id]; 113 : 0 : pthread_rwlock_unlock (&dbg->mem_rwl); 114 : 0 : return result; 115 : : } 116 : : 117 : : void * 118 : 46966 : __libdw_allocate (Dwarf *dbg, size_t minsize, size_t align) 119 : : { 120 : 46966 : size_t size = MAX (dbg->mem_default_size, 121 : : (align - 1 + 122 : : 2 * minsize + offsetof (struct libdw_memblock, mem))); 123 : 46966 : struct libdw_memblock *newp = malloc (size); 124 [ - + ]: 46966 : if (newp == NULL) 125 : 0 : dbg->oom_handler (); 126 : : 127 : 46966 : uintptr_t result = ((uintptr_t) newp->mem + align - 1) & ~(align - 1); 128 : : 129 : 46966 : newp->size = size - offsetof (struct libdw_memblock, mem); 130 : 46966 : newp->remaining = (uintptr_t) newp + size - (result + minsize); 131 : : 132 : 46966 : pthread_rwlock_rdlock (&dbg->mem_rwl); 133 : 46966 : newp->prev = dbg->mem_tails[thread_id]; 134 : 46966 : dbg->mem_tails[thread_id] = newp; 135 : 46966 : pthread_rwlock_unlock (&dbg->mem_rwl); 136 : : 137 : 46966 : return (void *) result; 138 : : } 139 : : 140 : : 141 : : Dwarf_OOM 142 : 0 : dwarf_new_oom_handler (Dwarf *dbg, Dwarf_OOM handler) 143 : : { 144 : 0 : Dwarf_OOM old = dbg->oom_handler; 145 : 0 : dbg->oom_handler = handler; 146 : 0 : return old; 147 : : } 148 : : 149 : : 150 : : void 151 : : __attribute ((noreturn)) attribute_hidden 152 : 0 : __libdw_oom (void) 153 : : { 154 : 0 : while (1) 155 : 0 : error (EXIT_FAILURE, ENOMEM, "libdw"); 156 : : }