ref: 4573bb5550de7917d8fc6276a3650a3d2dfedff0
dir: /sys/src/libc/port/malloc.c/
#include <u.h>
#include <libc.h>
#include <pool.h>
#include <tos.h>
static void* sbrkalloc(ulong);
static int sbrkmerge(void*, void*);
static void plock(Pool*);
static void punlock(Pool*);
static void pprint(Pool*, char*, ...);
static void ppanic(Pool*, char*, ...);
typedef struct Private Private;
struct Private {
Lock lk;
int pid;
int printfd; /* gets debugging output if set */
};
Private sbrkmempriv;
static Pool sbrkmem = {
.name= "sbrkmem",
.maxsize= (3840UL-1)*1024*1024, /* up to ~0xf0000000 */
.minarena= 4*1024,
.quantum= 32,
.alloc= sbrkalloc,
.merge= sbrkmerge,
.flags= 0,
.lock= plock,
.unlock= punlock,
.print= pprint,
.panic= ppanic,
.private= &sbrkmempriv,
};
Pool *mainmem = &sbrkmem;
Pool *imagmem = &sbrkmem;
/*
* we do minimal bookkeeping so we can tell pool
* whether two blocks are adjacent and thus mergeable.
*/
static void*
sbrkalloc(ulong n)
{
ulong *x;
n += 2*sizeof(ulong); /* two longs for us */
x = sbrk(n);
if(x == (void*)-1)
return nil;
x[0] = (n+7)&~7; /* sbrk rounds size up to mult. of 8 */
x[1] = 0xDeadBeef;
return x+2;
}
static int
sbrkmerge(void *x, void *y)
{
ulong *lx, *ly;
lx = x;
if(lx[-1] != 0xDeadBeef)
abort();
if((uchar*)lx+lx[-2] == (uchar*)y) {
ly = y;
lx[-2] += ly[-2];
return 1;
}
return 0;
}
static void
plock(Pool *p)
{
Private *pv;
pv = p->private;
lock(&pv->lk);
if(pv->pid != 0)
abort();
pv->pid = _tos->pid;
}
static void
punlock(Pool *p)
{
Private *pv;
pv = p->private;
if(pv->pid != _tos->pid)
abort();
pv->pid = 0;
unlock(&pv->lk);
}
static int
checkenv(void)
{
int n, fd;
char buf[20];
fd = open("/env/MALLOCFD", OREAD|OCEXEC);
if(fd < 0)
return -1;
n = read(fd, buf, sizeof buf);
close(fd);
if(n < 0)
return -1;
if(n >= sizeof buf)
n = sizeof(buf)-1;
buf[n] = 0;
n = atoi(buf);
if(n == 0)
n = -1;
return n;
}
static void
pprint(Pool *p, char *fmt, ...)
{
va_list v;
Private *pv;
pv = p->private;
if(pv->printfd == 0)
pv->printfd = checkenv();
if(pv->printfd <= 0)
pv->printfd = 2;
va_start(v, fmt);
vfprint(pv->printfd, fmt, v);
va_end(v);
}
static char panicbuf[256];
static void
ppanic(Pool *p, char *fmt, ...)
{
va_list v;
int n;
char *msg;
Private *pv;
pv = p->private;
assert(canlock(&pv->lk)==0);
if(pv->printfd == 0)
pv->printfd = checkenv();
if(pv->printfd <= 0)
pv->printfd = 2;
msg = panicbuf;
va_start(v, fmt);
n = vseprint(msg, msg+sizeof panicbuf, fmt, v) - msg;
write(2, "panic: ", 7);
write(2, msg, n);
write(2, "\n", 1);
if(pv->printfd != 2){
write(pv->printfd, "panic: ", 7);
write(pv->printfd, msg, n);
write(pv->printfd, "\n", 1);
}
va_end(v);
// unlock(&pv->lk);
abort();
}
/* - everything from here down should be the same in libc, libdebugmalloc, and the kernel - */
/* - except the code for malloc(), which alternately doesn't clear or does. - */
/*
* Npadlong is the number of ulongs's to leave at the beginning of
* each allocated buffer for our own bookkeeping. We return to the callers
* a pointer that points immediately after our bookkeeping area. Incoming pointers
* must be decremented by that much, and outgoing pointers incremented.
* The malloc tag is stored at MallocOffset from the beginning of the block,
* and the realloc tag at ReallocOffset. The offsets are from the true beginning
* of the block, not the beginning the caller sees.
*
* The extra if(Npadlong != 0) in various places is a hint for the compiler to
* compile out function calls that would otherwise be no-ops.
*/
/* non tracing
*
enum {
Npadlong = 0,
MallocOffset = 0,
ReallocOffset = 0,
};
*
*/
/* tracing */
enum {
Npadlong = 2,
MallocOffset = 0,
ReallocOffset = 1
};
void*
malloc(ulong size)
{
void *v;
v = poolalloc(mainmem, size+Npadlong*sizeof(ulong));
if(Npadlong && v != nil) {
v = (ulong*)v+Npadlong;
setmalloctag(v, getcallerpc(&size));
setrealloctag(v, 0);
}
return v;
}
void*
mallocz(ulong size, int clr)
{
void *v;
v = poolalloc(mainmem, size+Npadlong*sizeof(ulong));
if(Npadlong && v != nil){
v = (ulong*)v+Npadlong;
setmalloctag(v, getcallerpc(&size));
setrealloctag(v, 0);
}
if(clr && v != nil)
memset(v, 0, size);
return v;
}
void*
mallocalign(ulong size, ulong align, long offset, ulong span)
{
void *v;
v = poolallocalign(mainmem, size+Npadlong*sizeof(ulong), align, offset-Npadlong*sizeof(ulong), span);
if(Npadlong && v != nil){
v = (ulong*)v+Npadlong;
setmalloctag(v, getcallerpc(&size));
setrealloctag(v, 0);
}
return v;
}
void
free(void *v)
{
if(v != nil)
poolfree(mainmem, (ulong*)v-Npadlong);
}
void*
realloc(void *v, ulong size)
{
void *nv;
if(size == 0){
free(v);
return nil;
}
if(v)
v = (ulong*)v-Npadlong;
size += Npadlong*sizeof(ulong);
if(nv = poolrealloc(mainmem, v, size)){
nv = (ulong*)nv+Npadlong;
setrealloctag(nv, getcallerpc(&v));
if(v == nil)
setmalloctag(nv, getcallerpc(&v));
}
return nv;
}
ulong
msize(void *v)
{
return poolmsize(mainmem, (ulong*)v-Npadlong)-Npadlong*sizeof(ulong);
}
void
setmalloctag(void *v, uintptr pc)
{
USED(v, pc);
if(Npadlong <= MallocOffset || v == nil)
return;
((ulong*)v)[-Npadlong+MallocOffset] = (ulong)pc;
}
void
setrealloctag(void *v, uintptr pc)
{
USED(v, pc);
if(Npadlong <= ReallocOffset || v == nil)
return;
((ulong*)v)[-Npadlong+ReallocOffset] = (ulong)pc;
}
uintptr
getmalloctag(void *v)
{
USED(v);
if(Npadlong <= MallocOffset)
return ~0;
return (int)((ulong*)v)[-Npadlong+MallocOffset];
}
uintptr
getrealloctag(void *v)
{
USED(v);
if(Npadlong <= ReallocOffset)
return ~0;
return (int)((ulong*)v)[-Npadlong+ReallocOffset];
}
void*
malloctopoolblock(void *v)
{
if(v == nil)
return nil;
return &((ulong*)v)[-Npadlong];
}