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os_dep.c
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os_dep.c
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/*
* Copyright 1988, 1989 Hans-J. Boehm, Alan J. Demers
* Copyright (c) 1991-1995 by Xerox Corporation. All rights reserved.
* Copyright (c) 1996-1999 by Silicon Graphics. All rights reserved.
* Copyright (c) 1999 by Hewlett-Packard Company. All rights reserved.
*
* THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
* OR IMPLIED. ANY USE IS AT YOUR OWN RISK.
*
* Permission is hereby granted to use or copy this program
* for any purpose, provided the above notices are retained on all copies.
* Permission to modify the code and to distribute modified code is granted,
* provided the above notices are retained, and a notice that the code was
* modified is included with the above copyright notice.
*/
# include "private/gc_priv.h"
# if defined(LINUX) && !defined(POWERPC)
# include <linux/version.h>
# if (LINUX_VERSION_CODE <= 0x10400)
/* Ugly hack to get struct sigcontext_struct definition. Required */
/* for some early 1.3.X releases. Will hopefully go away soon. */
/* in some later Linux releases, asm/sigcontext.h may have to */
/* be included instead. */
# define __KERNEL__
# include <asm/signal.h>
# undef __KERNEL__
# else
/* Kernels prior to 2.1.1 defined struct sigcontext_struct instead of */
/* struct sigcontext. libc6 (glibc2) uses "struct sigcontext" in */
/* prototypes, so we have to include the top-level sigcontext.h to */
/* make sure the former gets defined to be the latter if appropriate. */
# include <features.h>
# if 2 <= __GLIBC__
# if 2 == __GLIBC__ && 0 == __GLIBC_MINOR__
/* glibc 2.1 no longer has sigcontext.h. But signal.h */
/* has the right declaration for glibc 2.1. */
# include <sigcontext.h>
# endif /* 0 == __GLIBC_MINOR__ */
# else /* not 2 <= __GLIBC__ */
/* libc5 doesn't have <sigcontext.h>: go directly with the kernel */
/* one. Check LINUX_VERSION_CODE to see which we should reference. */
# include <asm/sigcontext.h>
# endif /* 2 <= __GLIBC__ */
# endif
# endif
# if !defined(OS2) && !defined(PCR) && !defined(AMIGA) && !defined(MACOS) \
&& !defined(MSWINCE)
# include <sys/types.h>
# if !defined(MSWIN32) && !defined(SUNOS4)
# include <unistd.h>
# endif
# endif
# include <stdio.h>
# if defined(MSWINCE)
# define SIGSEGV 0 /* value is irrelevant */
# else
# include <signal.h>
# endif
#if defined(LINUX) || defined(LINUX_STACKBOTTOM)
# include <ctype.h>
#endif
/* Blatantly OS dependent routines, except for those that are related */
/* to dynamic loading. */
# if defined(HEURISTIC2) || defined(SEARCH_FOR_DATA_START)
# define NEED_FIND_LIMIT
# endif
# if !defined(STACKBOTTOM) && defined(HEURISTIC2)
# define NEED_FIND_LIMIT
# endif
# if (defined(SUNOS4) && defined(DYNAMIC_LOADING)) && !defined(PCR)
# define NEED_FIND_LIMIT
# endif
# if (defined(SVR4) || defined(AUX) || defined(DGUX) \
|| (defined(LINUX) && defined(SPARC))) && !defined(PCR)
# define NEED_FIND_LIMIT
# endif
#if defined(FREEBSD) && (defined(I386) || defined(X86_64) || defined(powerpc) || defined(__powerpc__))
# include <machine/trap.h>
# if !defined(PCR)
# define NEED_FIND_LIMIT
# endif
#endif
#if (defined(NETBSD) || defined(OPENBSD)) && defined(__ELF__) \
&& !defined(NEED_FIND_LIMIT)
/* Used by GC_init_netbsd_elf() below. */
# define NEED_FIND_LIMIT
#endif
#ifdef NEED_FIND_LIMIT
# include <setjmp.h>
#endif
#ifdef AMIGA
# define GC_AMIGA_DEF
# include "AmigaOS.c"
# undef GC_AMIGA_DEF
#endif
#if defined(MSWIN32) || defined(MSWINCE) || defined(CYGWIN32)
# define WIN32_LEAN_AND_MEAN
# define NOSERVICE
# include <windows.h>
#endif
#ifdef MACOS
# include <Processes.h>
#endif
#ifdef IRIX5
# include <sys/uio.h>
# include <malloc.h> /* for locking */
#endif
#if defined(USE_MMAP) || defined(USE_MUNMAP)
# ifndef USE_MMAP
--> USE_MUNMAP requires USE_MMAP
# endif
# include <sys/types.h>
# include <sys/mman.h>
# include <sys/stat.h>
# include <errno.h>
#endif
#ifdef UNIX_LIKE
# include <fcntl.h>
# if defined(SUNOS5SIGS) && !defined(FREEBSD)
# include <sys/siginfo.h>
# endif
/* Define SETJMP and friends to be the version that restores */
/* the signal mask. */
# define SETJMP(env) sigsetjmp(env, 1)
# define LONGJMP(env, val) siglongjmp(env, val)
# define JMP_BUF sigjmp_buf
#else
# define SETJMP(env) setjmp(env)
# define LONGJMP(env, val) longjmp(env, val)
# define JMP_BUF jmp_buf
#endif
#ifdef DARWIN
/* for get_etext and friends */
#include <mach-o/getsect.h>
#endif
#ifdef DJGPP
/* Apparently necessary for djgpp 2.01. May cause problems with */
/* other versions. */
typedef long unsigned int caddr_t;
#endif
#ifdef PCR
# include "il/PCR_IL.h"
# include "th/PCR_ThCtl.h"
# include "mm/PCR_MM.h"
#endif
#if !defined(NO_EXECUTE_PERMISSION)
# define OPT_PROT_EXEC PROT_EXEC
#else
# define OPT_PROT_EXEC 0
#endif
#if defined(LINUX) && \
(defined(USE_PROC_FOR_LIBRARIES) || defined(IA64) || !defined(SMALL_CONFIG))
/* We need to parse /proc/self/maps, either to find dynamic libraries, */
/* and/or to find the register backing store base (IA64). Do it once */
/* here. */
#define READ read
/* Repeatedly perform a read call until the buffer is filled or */
/* we encounter EOF. */
ssize_t GC_repeat_read(int fd, char *buf, size_t count)
{
ssize_t num_read = 0;
ssize_t result;
while (num_read < count) {
result = READ(fd, buf + num_read, count - num_read);
if (result < 0) return result;
if (result == 0) break;
num_read += result;
}
return num_read;
}
/*
* Apply fn to a buffer containing the contents of /proc/self/maps.
* Return the result of fn or, if we failed, 0.
* We currently do nothing to /proc/self/maps other than simply read
* it. This code could be simplified if we could determine its size
* ahead of time.
*/
word GC_apply_to_maps(word (*fn)(char *))
{
int f;
int result;
size_t maps_size = 4000; /* Initial guess. */
static char init_buf[1];
static char *maps_buf = init_buf;
static size_t maps_buf_sz = 1;
/* Read /proc/self/maps, growing maps_buf as necessary. */
/* Note that we may not allocate conventionally, and */
/* thus can't use stdio. */
do {
if (maps_size >= maps_buf_sz) {
/* Grow only by powers of 2, since we leak "too small" buffers. */
while (maps_size >= maps_buf_sz) maps_buf_sz *= 2;
maps_buf = GC_scratch_alloc(maps_buf_sz);
if (maps_buf == 0) return 0;
}
f = open("/proc/self/maps", O_RDONLY);
if (-1 == f) return 0;
maps_size = 0;
do {
result = GC_repeat_read(f, maps_buf, maps_buf_sz-1);
if (result <= 0) return 0;
maps_size += result;
} while (result == maps_buf_sz-1);
close(f);
} while (maps_size >= maps_buf_sz);
maps_buf[maps_size] = '\0';
/* Apply fn to result. */
return fn(maps_buf);
}
#endif /* Need GC_apply_to_maps */
#if defined(LINUX) && (defined(USE_PROC_FOR_LIBRARIES) || defined(IA64))
//
// GC_parse_map_entry parses an entry from /proc/self/maps so we can
// locate all writable data segments that belong to shared libraries.
// The format of one of these entries and the fields we care about
// is as follows:
// XXXXXXXX-XXXXXXXX r-xp 00000000 30:05 260537 name of mapping...\n
// ^^^^^^^^ ^^^^^^^^ ^^^^ ^^
// start end prot maj_dev
//
// Note that since about auguat 2003 kernels, the columns no longer have
// fixed offsets on 64-bit kernels. Hence we no longer rely on fixed offsets
// anywhere, which is safer anyway.
//
/*
* Assign various fields of the first line in buf_ptr to *start, *end,
* *prot_buf and *maj_dev. Only *prot_buf may be set for unwritable maps.
*/
char *GC_parse_map_entry(char *buf_ptr, word *start, word *end,
char *prot_buf, unsigned int *maj_dev)
{
char *start_start, *end_start, *prot_start, *maj_dev_start;
char *p;
char *endp;
if (buf_ptr == NULL || *buf_ptr == '\0') {
return NULL;
}
p = buf_ptr;
while (isspace(*p)) ++p;
start_start = p;
GC_ASSERT(isxdigit(*start_start));
*start = strtoul(start_start, &endp, 16); p = endp;
GC_ASSERT(*p=='-');
++p;
end_start = p;
GC_ASSERT(isxdigit(*end_start));
*end = strtoul(end_start, &endp, 16); p = endp;
GC_ASSERT(isspace(*p));
while (isspace(*p)) ++p;
prot_start = p;
GC_ASSERT(*prot_start == 'r' || *prot_start == '-');
memcpy(prot_buf, prot_start, 4);
prot_buf[4] = '\0';
if (prot_buf[1] == 'w') {/* we can skip the rest if it's not writable. */
/* Skip past protection field to offset field */
while (!isspace(*p)) ++p; while (isspace(*p)) ++p;
GC_ASSERT(isxdigit(*p));
/* Skip past offset field, which we ignore */
while (!isspace(*p)) ++p; while (isspace(*p)) ++p;
maj_dev_start = p;
GC_ASSERT(isxdigit(*maj_dev_start));
*maj_dev = strtoul(maj_dev_start, NULL, 16);
}
while (*p && *p++ != '\n');
return p;
}
#endif /* Need to parse /proc/self/maps. */
#if defined(SEARCH_FOR_DATA_START)
/* The I386 case can be handled without a search. The Alpha case */
/* used to be handled differently as well, but the rules changed */
/* for recent Linux versions. This seems to be the easiest way to */
/* cover all versions. */
# ifdef LINUX
/* Some Linux distributions arrange to define __data_start. Some */
/* define data_start as a weak symbol. The latter is technically */
/* broken, since the user program may define data_start, in which */
/* case we lose. Nonetheless, we try both, prefering __data_start. */
/* We assume gcc-compatible pragmas. */
# pragma weak __data_start
extern int __data_start[];
# pragma weak data_start
extern int data_start[];
# endif /* LINUX */
extern int _end[];
ptr_t GC_data_start;
void GC_init_linux_data_start()
{
extern ptr_t GC_find_limit();
# ifdef LINUX
/* Try the easy approaches first: */
if ((ptr_t)__data_start != 0) {
GC_data_start = (ptr_t)(__data_start);
return;
}
if ((ptr_t)data_start != 0) {
GC_data_start = (ptr_t)(data_start);
return;
}
# endif /* LINUX */
GC_data_start = GC_find_limit((ptr_t)(_end), FALSE);
}
#endif
# ifdef ECOS
# ifndef ECOS_GC_MEMORY_SIZE
# define ECOS_GC_MEMORY_SIZE (448 * 1024)
# endif /* ECOS_GC_MEMORY_SIZE */
// setjmp() function, as described in ANSI para 7.6.1.1
#undef SETJMP
#define SETJMP( __env__ ) hal_setjmp( __env__ )
// FIXME: This is a simple way of allocating memory which is
// compatible with ECOS early releases. Later releases use a more
// sophisticated means of allocating memory than this simple static
// allocator, but this method is at least bound to work.
static char memory[ECOS_GC_MEMORY_SIZE];
static char *brk = memory;
static void *tiny_sbrk(ptrdiff_t increment)
{
void *p = brk;
brk += increment;
if (brk > memory + sizeof memory)
{
brk -= increment;
return NULL;
}
return p;
}
#define sbrk tiny_sbrk
# endif /* ECOS */
#if (defined(NETBSD) || defined(OPENBSD)) && defined(__ELF__)
ptr_t GC_data_start;
void GC_init_netbsd_elf()
{
extern ptr_t GC_find_limit();
extern char **environ;
/* This may need to be environ, without the underscore, for */
/* some versions. */
GC_data_start = GC_find_limit((ptr_t)&environ, FALSE);
}
#endif
# ifdef OS2
# include <stddef.h>
# if !defined(__IBMC__) && !defined(__WATCOMC__) /* e.g. EMX */
struct exe_hdr {
unsigned short magic_number;
unsigned short padding[29];
long new_exe_offset;
};
#define E_MAGIC(x) (x).magic_number
#define EMAGIC 0x5A4D
#define E_LFANEW(x) (x).new_exe_offset
struct e32_exe {
unsigned char magic_number[2];
unsigned char byte_order;
unsigned char word_order;
unsigned long exe_format_level;
unsigned short cpu;
unsigned short os;
unsigned long padding1[13];
unsigned long object_table_offset;
unsigned long object_count;
unsigned long padding2[31];
};
#define E32_MAGIC1(x) (x).magic_number[0]
#define E32MAGIC1 'L'
#define E32_MAGIC2(x) (x).magic_number[1]
#define E32MAGIC2 'X'
#define E32_BORDER(x) (x).byte_order
#define E32LEBO 0
#define E32_WORDER(x) (x).word_order
#define E32LEWO 0
#define E32_CPU(x) (x).cpu
#define E32CPU286 1
#define E32_OBJTAB(x) (x).object_table_offset
#define E32_OBJCNT(x) (x).object_count
struct o32_obj {
unsigned long size;
unsigned long base;
unsigned long flags;
unsigned long pagemap;
unsigned long mapsize;
unsigned long reserved;
};
#define O32_FLAGS(x) (x).flags
#define OBJREAD 0x0001L
#define OBJWRITE 0x0002L
#define OBJINVALID 0x0080L
#define O32_SIZE(x) (x).size
#define O32_BASE(x) (x).base
# else /* IBM's compiler */
/* A kludge to get around what appears to be a header file bug */
# ifndef WORD
# define WORD unsigned short
# endif
# ifndef DWORD
# define DWORD unsigned long
# endif
# define EXE386 1
# include <newexe.h>
# include <exe386.h>
# endif /* __IBMC__ */
# define INCL_DOSEXCEPTIONS
# define INCL_DOSPROCESS
# define INCL_DOSERRORS
# define INCL_DOSMODULEMGR
# define INCL_DOSMEMMGR
# include <os2.h>
/* Disable and enable signals during nontrivial allocations */
void GC_disable_signals(void)
{
ULONG nest;
DosEnterMustComplete(&nest);
if (nest != 1) ABORT("nested GC_disable_signals");
}
void GC_enable_signals(void)
{
ULONG nest;
DosExitMustComplete(&nest);
if (nest != 0) ABORT("GC_enable_signals");
}
# else
# if !defined(PCR) && !defined(AMIGA) && !defined(MSWIN32) \
&& !defined(MSWINCE) \
&& !defined(MACOS) && !defined(DJGPP) && !defined(DOS4GW) \
&& !defined(NOSYS) && !defined(ECOS)
# if defined(SIG_BLOCK)
/* Use POSIX/SYSV interface */
# define SIGSET_T sigset_t
# define SIG_DEL(set, signal) sigdelset(&(set), (signal))
# define SIG_FILL(set) sigfillset(&set)
# define SIGSETMASK(old, new) sigprocmask(SIG_SETMASK, &(new), &(old))
# elif defined(sigmask) && !defined(UTS4) && !defined(HURD)
/* Use the traditional BSD interface */
# define SIGSET_T int
# define SIG_DEL(set, signal) (set) &= ~(sigmask(signal))
# define SIG_FILL(set) (set) = 0x7fffffff
/* Setting the leading bit appears to provoke a bug in some */
/* longjmp implementations. Most systems appear not to have */
/* a signal 32. */
# define SIGSETMASK(old, new) (old) = sigsetmask(new)
# else
# error undetectable signal API
# endif
static GC_bool mask_initialized = FALSE;
static SIGSET_T new_mask;
static SIGSET_T old_mask;
static SIGSET_T dummy;
#if defined(PRINTSTATS) && !defined(THREADS)
# define CHECK_SIGNALS
int GC_sig_disabled = 0;
#endif
void GC_disable_signals()
{
if (!mask_initialized) {
SIG_FILL(new_mask);
SIG_DEL(new_mask, SIGSEGV);
SIG_DEL(new_mask, SIGILL);
SIG_DEL(new_mask, SIGQUIT);
# ifdef SIGBUS
SIG_DEL(new_mask, SIGBUS);
# endif
# ifdef SIGIOT
SIG_DEL(new_mask, SIGIOT);
# endif
# ifdef SIGEMT
SIG_DEL(new_mask, SIGEMT);
# endif
# ifdef SIGTRAP
SIG_DEL(new_mask, SIGTRAP);
# endif
mask_initialized = TRUE;
}
# ifdef CHECK_SIGNALS
if (GC_sig_disabled != 0) ABORT("Nested disables");
GC_sig_disabled++;
# endif
SIGSETMASK(old_mask,new_mask);
}
void GC_enable_signals()
{
# ifdef CHECK_SIGNALS
if (GC_sig_disabled != 1) ABORT("Unmatched enable");
GC_sig_disabled--;
# endif
SIGSETMASK(dummy,old_mask);
}
# endif /* !PCR */
# endif /*!OS/2 */
/* Ivan Demakov: simplest way (to me) */
#if defined (DOS4GW)
void GC_disable_signals() { }
void GC_enable_signals() { }
#endif
/* Find the page size */
word GC_page_size;
# if defined(MSWIN32) || defined(MSWINCE) || defined (CYGWIN32)
void GC_setpagesize()
{
GetSystemInfo(&GC_sysinfo);
GC_page_size = GC_sysinfo.dwPageSize;
}
# else
# if defined(MPROTECT_VDB) || defined(PROC_VDB) || defined(USE_MMAP) \
|| defined(USE_MUNMAP)
void GC_setpagesize()
{
GC_page_size = GETPAGESIZE();
}
# else
/* It's acceptable to fake it. */
void GC_setpagesize()
{
GC_page_size = HBLKSIZE;
}
# endif
# endif
/*
* Find the base of the stack.
* Used only in single-threaded environment.
* With threads, GC_mark_roots needs to know how to do this.
* Called with allocator lock held.
*/
# if defined(MSWIN32) || defined(MSWINCE)
# define is_writable(prot) ((prot) == PAGE_READWRITE \
|| (prot) == PAGE_WRITECOPY \
|| (prot) == PAGE_EXECUTE_READWRITE \
|| (prot) == PAGE_EXECUTE_WRITECOPY)
/* Return the number of bytes that are writable starting at p. */
/* The pointer p is assumed to be page aligned. */
/* If base is not 0, *base becomes the beginning of the */
/* allocation region containing p. */
word GC_get_writable_length(ptr_t p, ptr_t *base)
{
MEMORY_BASIC_INFORMATION buf;
word result;
word protect;
result = VirtualQuery(p, &buf, sizeof(buf));
if (result != sizeof(buf)) ABORT("Weird VirtualQuery result");
if (base != 0) *base = (ptr_t)(buf.AllocationBase);
protect = (buf.Protect & ~(PAGE_GUARD | PAGE_NOCACHE));
if (!is_writable(protect)) {
return(0);
}
if (buf.State != MEM_COMMIT) return(0);
return(buf.RegionSize);
}
ptr_t GC_get_stack_base()
{
int dummy;
ptr_t sp = (ptr_t)(&dummy);
ptr_t trunc_sp = (ptr_t)((word)sp & ~(GC_page_size - 1));
word size = GC_get_writable_length(trunc_sp, 0);
return(trunc_sp + size);
}
# endif /* MS Windows */
# ifdef BEOS
# include <kernel/OS.h>
ptr_t GC_get_stack_base(){
thread_info th;
get_thread_info(find_thread(NULL),&th);
return th.stack_end;
}
# endif /* BEOS */
# ifdef OS2
ptr_t GC_get_stack_base()
{
PTIB ptib;
PPIB ppib;
if (DosGetInfoBlocks(&ptib, &ppib) != NO_ERROR) {
GC_err_printf0("DosGetInfoBlocks failed\n");
ABORT("DosGetInfoBlocks failed\n");
}
return((ptr_t)(ptib -> tib_pstacklimit));
}
# endif /* OS2 */
# ifdef AMIGA
# define GC_AMIGA_SB
# include "AmigaOS.c"
# undef GC_AMIGA_SB
# endif /* AMIGA */
# if defined(NEED_FIND_LIMIT) || defined(UNIX_LIKE)
# ifdef __STDC__
typedef void (*handler)(int);
# else
typedef void (*handler)();
# endif
# if defined(SUNOS5SIGS) || defined(IRIX5) || defined(OSF1) \
|| defined(HURD) || defined(NETBSD)
static struct sigaction old_segv_act;
# if defined(IRIX5) || defined(HPUX) \
|| defined(HURD) || defined(NETBSD)
static struct sigaction old_bus_act;
# endif
# else
static handler old_segv_handler, old_bus_handler;
# endif
# ifdef __STDC__
void GC_set_and_save_fault_handler(handler h)
# else
void GC_set_and_save_fault_handler(h)
handler h;
# endif
{
# if defined(SUNOS5SIGS) || defined(IRIX5) \
|| defined(OSF1) || defined(HURD) || defined(NETBSD)
struct sigaction act;
act.sa_handler = h;
# if 0 /* Was necessary for Solaris 2.3 and very temporary */
/* NetBSD bugs. */
act.sa_flags = SA_RESTART | SA_NODEFER;
# else
act.sa_flags = SA_RESTART;
# endif
(void) sigemptyset(&act.sa_mask);
# ifdef GC_IRIX_THREADS
/* Older versions have a bug related to retrieving and */
/* and setting a handler at the same time. */
(void) sigaction(SIGSEGV, 0, &old_segv_act);
(void) sigaction(SIGSEGV, &act, 0);
(void) sigaction(SIGBUS, 0, &old_bus_act);
(void) sigaction(SIGBUS, &act, 0);
# else
(void) sigaction(SIGSEGV, &act, &old_segv_act);
# if defined(IRIX5) \
|| defined(HPUX) || defined(HURD) || defined(NETBSD)
/* Under Irix 5.x or HP/UX, we may get SIGBUS. */
/* Pthreads doesn't exist under Irix 5.x, so we */
/* don't have to worry in the threads case. */
(void) sigaction(SIGBUS, &act, &old_bus_act);
# endif
# endif /* GC_IRIX_THREADS */
# else
old_segv_handler = signal(SIGSEGV, h);
# ifdef SIGBUS
old_bus_handler = signal(SIGBUS, h);
# endif
# endif
}
# endif /* NEED_FIND_LIMIT || UNIX_LIKE */
# ifdef NEED_FIND_LIMIT
/* Some tools to implement HEURISTIC2 */
# define MIN_PAGE_SIZE 256 /* Smallest conceivable page size, bytes */
/* static */ JMP_BUF GC_jmp_buf;
/*ARGSUSED*/
void GC_fault_handler(sig)
int sig;
{
LONGJMP(GC_jmp_buf, 1);
}
void GC_setup_temporary_fault_handler()
{
GC_set_and_save_fault_handler(GC_fault_handler);
}
void GC_reset_fault_handler()
{
# if defined(SUNOS5SIGS) || defined(IRIX5) \
|| defined(OSF1) || defined(HURD) || defined(NETBSD)
(void) sigaction(SIGSEGV, &old_segv_act, 0);
# if defined(IRIX5) \
|| defined(HPUX) || defined(HURD) || defined(NETBSD)
(void) sigaction(SIGBUS, &old_bus_act, 0);
# endif
# else
(void) signal(SIGSEGV, old_segv_handler);
# ifdef SIGBUS
(void) signal(SIGBUS, old_bus_handler);
# endif
# endif
}
/* Return the first nonaddressible location > p (up) or */
/* the smallest location q s.t. [q,p) is addressable (!up). */
/* We assume that p (up) or p-1 (!up) is addressable. */
ptr_t GC_find_limit(p, up)
ptr_t p;
GC_bool up;
{
static VOLATILE ptr_t result;
/* Needs to be static, since otherwise it may not be */
/* preserved across the longjmp. Can safely be */
/* static since it's only called once, with the */
/* allocation lock held. */
GC_setup_temporary_fault_handler();
if (SETJMP(GC_jmp_buf) == 0) {
result = (ptr_t)(((word)(p))
& ~(MIN_PAGE_SIZE-1));
for (;;) {
if (up) {
result += MIN_PAGE_SIZE;
} else {
result -= MIN_PAGE_SIZE;
}
GC_noop1((word)(*result));
}
}
GC_reset_fault_handler();
if (!up) {
result += MIN_PAGE_SIZE;
}
return(result);
}
# endif
#if defined(ECOS) || defined(NOSYS)
ptr_t GC_get_stack_base()
{
return STACKBOTTOM;
}
#endif
#ifdef HPUX_STACKBOTTOM
#include <sys/param.h>
#include <sys/pstat.h>
ptr_t GC_get_register_stack_base(void)
{
struct pst_vm_status vm_status;
int i = 0;
while (pstat_getprocvm(&vm_status, sizeof(vm_status), 0, i++) == 1) {
if (vm_status.pst_type == PS_RSESTACK) {
return (ptr_t) vm_status.pst_vaddr;
}
}
/* old way to get the register stackbottom */
return (ptr_t)(((word)GC_stackbottom - BACKING_STORE_DISPLACEMENT - 1)
& ~(BACKING_STORE_ALIGNMENT - 1));
}
#endif /* HPUX_STACK_BOTTOM */
#ifdef LINUX_STACKBOTTOM
#include <sys/types.h>
#include <sys/stat.h>
# define STAT_SKIP 27 /* Number of fields preceding startstack */
/* field in /proc/self/stat */
#ifdef USE_LIBC_PRIVATES
# pragma weak __libc_stack_end
extern ptr_t __libc_stack_end;
#endif
# ifdef IA64
/* Try to read the backing store base from /proc/self/maps. */
/* We look for the writable mapping with a 0 major device, */
/* which is as close to our frame as possible, but below it.*/
static word backing_store_base_from_maps(char *maps)
{
char prot_buf[5];
char *buf_ptr = maps;
word start, end;
unsigned int maj_dev;
word current_best = 0;
word dummy;
for (;;) {
buf_ptr = GC_parse_map_entry(buf_ptr, &start, &end, prot_buf, &maj_dev);
if (buf_ptr == NULL) return current_best;
if (prot_buf[1] == 'w' && maj_dev == 0) {
if (end < (word)(&dummy) && start > current_best) current_best = start;
}
}
return current_best;
}
static word backing_store_base_from_proc(void)
{
return GC_apply_to_maps(backing_store_base_from_maps);
}
# ifdef USE_LIBC_PRIVATES
# pragma weak __libc_ia64_register_backing_store_base
extern ptr_t __libc_ia64_register_backing_store_base;
# endif
ptr_t GC_get_register_stack_base(void)
{
# ifdef USE_LIBC_PRIVATES
if (0 != &__libc_ia64_register_backing_store_base
&& 0 != __libc_ia64_register_backing_store_base) {
/* Glibc 2.2.4 has a bug such that for dynamically linked */
/* executables __libc_ia64_register_backing_store_base is */
/* defined but uninitialized during constructor calls. */
/* Hence we check for both nonzero address and value. */
return __libc_ia64_register_backing_store_base;
}
# endif
word result = backing_store_base_from_proc();
if (0 == result) {
/* Use dumb heuristics. Works only for default configuration. */
result = (word)GC_stackbottom - BACKING_STORE_DISPLACEMENT;
result += BACKING_STORE_ALIGNMENT - 1;
result &= ~(BACKING_STORE_ALIGNMENT - 1);
/* Verify that it's at least readable. If not, we goofed. */
GC_noop1(*(word *)result);
}
return (ptr_t)result;
}
# endif
ptr_t GC_linux_stack_base(void)
{
/* We read the stack base value from /proc/self/stat. We do this */
/* using direct I/O system calls in order to avoid calling malloc */
/* in case REDIRECT_MALLOC is defined. */
# define STAT_BUF_SIZE 4096
# define STAT_READ read
/* Should probably call the real read, if read is wrapped. */
char stat_buf[STAT_BUF_SIZE];
int f;
char c;
word result = 0;
size_t i, buf_offset = 0;
/* First try the easy way. This should work for glibc 2.2 */
/* This fails in a prelinked ("prelink" command) executable */
/* since the correct value of __libc_stack_end never */
/* becomes visible to us. The second test works around */
/* this. */
# ifdef USE_LIBC_PRIVATES
if (0 != &__libc_stack_end && 0 != __libc_stack_end ) {
# ifdef IA64
/* Some versions of glibc set the address 16 bytes too */
/* low while the initialization code is running. */
if (((word)__libc_stack_end & 0xfff) + 0x10 < 0x1000) {
return __libc_stack_end + 0x10;
} /* Otherwise it's not safe to add 16 bytes and we fall */
/* back to using /proc. */
# else
# ifdef SPARC
/* Older versions of glibc for 64-bit Sparc do not set
* this variable correctly, it gets set to either zero
* or one.
*/
if (__libc_stack_end != (ptr_t) (unsigned long)0x1)
return __libc_stack_end;
# else
return __libc_stack_end;
# endif
# endif
}
# endif
f = open("/proc/self/stat", O_RDONLY);
if (f < 0 || STAT_READ(f, stat_buf, STAT_BUF_SIZE) < 2 * STAT_SKIP) {
ABORT("Couldn't read /proc/self/stat");
}
c = stat_buf[buf_offset++];
/* Skip the required number of fields. This number is hopefully */
/* constant across all Linux implementations. */
for (i = 0; i < STAT_SKIP; ++i) {
while (isspace(c)) c = stat_buf[buf_offset++];
while (!isspace(c)) c = stat_buf[buf_offset++];
}
while (isspace(c)) c = stat_buf[buf_offset++];
while (isdigit(c)) {
result *= 10;
result += c - '0';
c = stat_buf[buf_offset++];
}
close(f);
if (result < 0x10000000) ABORT("Absurd stack bottom value");
return (ptr_t)result;
}
#endif /* LINUX_STACKBOTTOM */
#ifdef FREEBSD_STACKBOTTOM
/* This uses an undocumented sysctl call, but at least one expert */
/* believes it will stay. */
#include <unistd.h>
#include <sys/types.h>
#include <sys/sysctl.h>
ptr_t GC_freebsd_stack_base(void)
{
int nm[2] = {CTL_KERN, KERN_USRSTACK};
ptr_t base;