mpv/ta/ta.c

407 lines
12 KiB
C

/* Copyright (C) 2017 the mpv developers
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <assert.h>
#define TA_NO_WRAPPERS
#include "ta.h"
// Note: the actual minimum alignment is dictated by malloc(). It doesn't
// make sense to set this value higher than malloc's alignment.
#define MIN_ALIGN 16
#if !defined(TA_MEMORY_DEBUGGING)
#if !defined(NDEBUG)
#define TA_MEMORY_DEBUGGING 1
#else
#define TA_MEMORY_DEBUGGING 0
#endif
#endif
struct ta_header {
size_t size; // size of the user allocation
// Invariant: parent!=NULL => prev==NULL
struct ta_header *prev; // siblings list (by destructor order)
struct ta_header *next;
// Invariant: parent==NULL || parent->child==this
struct ta_header *child; // points to first child
struct ta_header *parent; // set for _first_ child only, NULL otherwise
void (*destructor)(void *);
#if TA_MEMORY_DEBUGGING
unsigned int canary;
struct ta_header *leak_next;
struct ta_header *leak_prev;
const char *name;
#endif
};
#define CANARY 0xD3ADB3EF
union aligned_header {
struct ta_header ta;
// Make sure to satisfy typical alignment requirements
void *align_ptr;
int align_int;
double align_d;
long long align_ll;
char align_min[(sizeof(struct ta_header) + MIN_ALIGN - 1) & ~(MIN_ALIGN - 1)];
};
#define PTR_TO_HEADER(ptr) (&((union aligned_header *)(ptr) - 1)->ta)
#define PTR_FROM_HEADER(h) ((void *)((union aligned_header *)(h) + 1))
#define MAX_ALLOC (((size_t)-1) - sizeof(union aligned_header))
static void ta_dbg_add(struct ta_header *h);
static void ta_dbg_check_header(struct ta_header *h);
static void ta_dbg_remove(struct ta_header *h);
static struct ta_header *get_header(void *ptr)
{
struct ta_header *h = ptr ? PTR_TO_HEADER(ptr) : NULL;
ta_dbg_check_header(h);
return h;
}
/* Set the parent allocation of ptr. If parent==NULL, remove the parent.
* Setting parent==NULL (with ptr!=NULL) unsets the parent of ptr.
* With ptr==NULL, the function does nothing.
*
* Warning: if ta_parent is a direct or indirect child of ptr, things will go
* wrong. The function will apparently succeed, but creates circular
* parent links, which are not allowed.
*/
void ta_set_parent(void *ptr, void *ta_parent)
{
struct ta_header *ch = get_header(ptr);
if (!ch)
return;
struct ta_header *new_parent = get_header(ta_parent);
// Unlink from previous parent
if (ch->prev)
ch->prev->next = ch->next;
if (ch->next)
ch->next->prev = ch->prev;
// If ch was the first child, change child link of old parent
if (ch->parent) {
assert(ch->parent->child == ch);
ch->parent->child = ch->next;
if (ch->parent->child) {
assert(!ch->parent->child->parent);
ch->parent->child->parent = ch->parent;
}
}
ch->next = ch->prev = ch->parent = NULL;
// Link to new parent - insert at start of list (LIFO destructor order)
if (new_parent) {
ch->next = new_parent->child;
if (ch->next) {
ch->next->prev = ch;
ch->next->parent = NULL;
}
new_parent->child = ch;
ch->parent = new_parent;
}
}
/* Return the parent allocation, or NULL if none or if ptr==NULL.
*
* Warning: do not use this for program logic, or I'll be sad.
*/
void *ta_get_parent(void *ptr)
{
struct ta_header *ch = get_header(ptr);
return ch ? ch->parent : NULL;
}
/* Allocate size bytes of memory. If ta_parent is not NULL, this is used as
* parent allocation (if ta_parent is freed, this allocation is automatically
* freed as well). size==0 allocates a block of size 0 (i.e. returns non-NULL).
* Returns NULL on OOM.
*/
void *ta_alloc_size(void *ta_parent, size_t size)
{
if (size >= MAX_ALLOC)
return NULL;
struct ta_header *h = malloc(sizeof(union aligned_header) + size);
if (!h)
return NULL;
*h = (struct ta_header) {.size = size};
ta_dbg_add(h);
void *ptr = PTR_FROM_HEADER(h);
ta_set_parent(ptr, ta_parent);
return ptr;
}
/* Exactly the same as ta_alloc_size(), but the returned memory block is
* initialized to 0.
*/
void *ta_zalloc_size(void *ta_parent, size_t size)
{
if (size >= MAX_ALLOC)
return NULL;
struct ta_header *h = calloc(1, sizeof(union aligned_header) + size);
if (!h)
return NULL;
*h = (struct ta_header) {.size = size};
ta_dbg_add(h);
void *ptr = PTR_FROM_HEADER(h);
ta_set_parent(ptr, ta_parent);
return ptr;
}
/* Reallocate the allocation given by ptr and return a new pointer. Much like
* realloc(), the returned pointer can be different, and on OOM, NULL is
* returned.
*
* size==0 is equivalent to ta_free(ptr).
* ptr==NULL is equivalent to ta_alloc_size(ta_parent, size).
*
* ta_parent is used only in the ptr==NULL case.
*
* Returns NULL if the operation failed.
* NULL is also returned if size==0.
*/
void *ta_realloc_size(void *ta_parent, void *ptr, size_t size)
{
if (size >= MAX_ALLOC)
return NULL;
if (!size) {
ta_free(ptr);
return NULL;
}
if (!ptr)
return ta_alloc_size(ta_parent, size);
struct ta_header *h = get_header(ptr);
struct ta_header *old_h = h;
if (h->size == size)
return ptr;
ta_dbg_remove(h);
h = realloc(h, sizeof(union aligned_header) + size);
ta_dbg_add(h ? h : old_h);
if (!h)
return NULL;
h->size = size;
if (h != old_h) {
// Relink parent
if (h->parent)
h->parent->child = h;
// Relink siblings
if (h->next)
h->next->prev = h;
if (h->prev)
h->prev->next = h;
// Relink children
if (h->child)
h->child->parent = h;
}
return PTR_FROM_HEADER(h);
}
/* Return the allocated size of ptr. This returns the size parameter of the
* most recent ta_alloc.../ta_realloc... call.
* If ptr==NULL, return 0.
*/
size_t ta_get_size(void *ptr)
{
struct ta_header *h = get_header(ptr);
return h ? h->size : 0;
}
/* Free all allocations that (recursively) have ptr as parent allocation, but
* do not free ptr itself.
*/
void ta_free_children(void *ptr)
{
struct ta_header *h = get_header(ptr);
while (h && h->child)
ta_free(PTR_FROM_HEADER(h->child));
}
/* Free the given allocation, and all of its direct and indirect children.
*/
void ta_free(void *ptr)
{
struct ta_header *h = get_header(ptr);
if (!h)
return;
if (h->destructor)
h->destructor(ptr);
ta_free_children(ptr);
ta_set_parent(ptr, NULL);
ta_dbg_remove(h);
free(h);
}
/* Set a destructor that is to be called when the given allocation is freed.
* (Whether the allocation is directly freed with ta_free() or indirectly by
* freeing its parent does not matter.) There is only one destructor. If an
* destructor was already set, it's overwritten.
*
* The destructor will be called with ptr as argument. The destructor can do
* almost anything, but it must not attempt to free or realloc ptr. The
* destructor is run before the allocation's children are freed (also, before
* their destructors are run).
*/
void ta_set_destructor(void *ptr, void (*destructor)(void *))
{
struct ta_header *h = get_header(ptr);
if (h)
h->destructor = destructor;
}
#if TA_MEMORY_DEBUGGING
#include <pthread.h>
static pthread_mutex_t ta_dbg_mutex = PTHREAD_MUTEX_INITIALIZER;
static bool enable_leak_check; // pretty much constant
static struct ta_header leak_node;
static char allocation_is_string;
static void ta_dbg_add(struct ta_header *h)
{
h->canary = CANARY;
if (enable_leak_check) {
pthread_mutex_lock(&ta_dbg_mutex);
h->leak_next = &leak_node;
h->leak_prev = leak_node.leak_prev;
leak_node.leak_prev->leak_next = h;
leak_node.leak_prev = h;
pthread_mutex_unlock(&ta_dbg_mutex);
}
}
static void ta_dbg_check_header(struct ta_header *h)
{
if (h) {
assert(h->canary == CANARY);
if (h->parent) {
assert(!h->prev);
assert(h->parent->child == h);
}
}
}
static void ta_dbg_remove(struct ta_header *h)
{
ta_dbg_check_header(h);
if (h->leak_next) { // assume checking for !=NULL invariant ok without lock
pthread_mutex_lock(&ta_dbg_mutex);
h->leak_next->leak_prev = h->leak_prev;
h->leak_prev->leak_next = h->leak_next;
pthread_mutex_unlock(&ta_dbg_mutex);
h->leak_next = h->leak_prev = NULL;
}
h->canary = 0;
}
static size_t get_children_size(struct ta_header *h)
{
size_t size = 0;
for (struct ta_header *s = h->child; s; s = s->next)
size += s->size + get_children_size(s);
return size;
}
static void print_leak_report(void)
{
pthread_mutex_lock(&ta_dbg_mutex);
if (leak_node.leak_next && leak_node.leak_next != &leak_node) {
size_t size = 0;
size_t num_blocks = 0;
fprintf(stderr, "Blocks not freed:\n");
fprintf(stderr, " %-20s %10s %10s %s\n",
"Ptr", "Bytes", "C. Bytes", "Name");
while (leak_node.leak_next != &leak_node) {
struct ta_header *cur = leak_node.leak_next;
// Don't list those with parent; logically, only parents are listed
if (!cur->next) {
size_t c_size = get_children_size(cur);
char name[30] = {0};
if (cur->name)
snprintf(name, sizeof(name), "%s", cur->name);
if (cur->name == &allocation_is_string) {
snprintf(name, sizeof(name), "'%.*s'",
(int)cur->size, (char *)PTR_FROM_HEADER(cur));
}
for (int n = 0; n < sizeof(name); n++) {
if (name[n] && name[n] < 0x20)
name[n] = '.';
}
fprintf(stderr, " %-20p %10zu %10zu %s\n",
cur, cur->size, c_size, name);
}
size += cur->size;
num_blocks += 1;
// Unlink, and don't confuse valgrind by leaving live pointers.
cur->leak_next->leak_prev = cur->leak_prev;
cur->leak_prev->leak_next = cur->leak_next;
cur->leak_next = cur->leak_prev = NULL;
}
fprintf(stderr, "%zu bytes in %zu blocks.\n", size, num_blocks);
}
pthread_mutex_unlock(&ta_dbg_mutex);
}
void ta_enable_leak_report(void)
{
pthread_mutex_lock(&ta_dbg_mutex);
enable_leak_check = true;
if (!leak_node.leak_prev && !leak_node.leak_next) {
leak_node.leak_prev = &leak_node;
leak_node.leak_next = &leak_node;
atexit(print_leak_report);
}
pthread_mutex_unlock(&ta_dbg_mutex);
}
/* Set a (static) string that will be printed if the memory allocation in ptr
* shows up on the leak report. The string must stay valid until ptr is freed.
* Calling it on ptr==NULL does nothing.
* Typically used to set location info.
* Always returns ptr (useful for chaining function calls).
*/
void *ta_dbg_set_loc(void *ptr, const char *loc)
{
struct ta_header *h = get_header(ptr);
if (h)
h->name = loc;
return ptr;
}
/* Mark the allocation as string. The leak report will print it literally.
*/
void *ta_dbg_mark_as_string(void *ptr)
{
// Specially handled by leak report code.
return ta_dbg_set_loc(ptr, &allocation_is_string);
}
#else
static void ta_dbg_add(struct ta_header *h){}
static void ta_dbg_check_header(struct ta_header *h){}
static void ta_dbg_remove(struct ta_header *h){}
void ta_enable_leak_report(void){}
void *ta_dbg_set_loc(void *ptr, const char *loc){return ptr;}
void *ta_dbg_mark_as_string(void *ptr){return ptr;}
#endif