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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.
* Copyright (c) 2008-2022 Ivan Maidanski
*
* 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(MPROTECT_VDB) && !defined(MSWIN32) && !defined(MSWINCE)) \
|| defined(GC_SOLARIS_THREADS) || defined(OPENBSD)
# include <signal.h>
#endif
#if defined(UNIX_LIKE) || defined(CYGWIN32) || defined(NACL) \
|| defined(SYMBIAN)
# include <fcntl.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. */
#ifdef AMIGA
# define GC_AMIGA_DEF
# include "extra/AmigaOS.c"
# undef GC_AMIGA_DEF
#endif
#ifdef MACOS
# include <Processes.h>
#endif
#ifdef IRIX5
# include <sys/uio.h>
# include <malloc.h> /* for locking */
#endif
#if defined(MMAP_SUPPORTED) || defined(ADD_HEAP_GUARD_PAGES)
# if defined(USE_MUNMAP) && !defined(USE_MMAP) && !defined(CPPCHECK)
# error Invalid config: USE_MUNMAP requires USE_MMAP
# endif
# include <sys/mman.h>
# include <sys/stat.h>
#endif
#if defined(ADD_HEAP_GUARD_PAGES) || defined(LINUX_STACKBOTTOM) \
|| defined(MMAP_SUPPORTED) || defined(NEED_PROC_MAPS)
# include <errno.h>
#endif
#if defined(DARWIN) && !defined(DYNAMIC_LOADING) \
&& !defined(GC_DONT_REGISTER_MAIN_STATIC_DATA)
/* 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)
STATIC GC_bool GC_pages_executable = TRUE;
#else
STATIC GC_bool GC_pages_executable = FALSE;
#endif
#define IGNORE_PAGES_EXECUTABLE 1
/* Undefined on GC_pages_executable real use. */
#if ((defined(LINUX_STACKBOTTOM) || defined(NEED_PROC_MAPS) \
|| defined(PROC_VDB) || defined(SOFT_VDB)) && !defined(PROC_READ)) \
|| defined(CPPCHECK)
# define PROC_READ read
/* Should probably call the real read, if read is wrapped. */
#endif
#if defined(LINUX_STACKBOTTOM) || defined(NEED_PROC_MAPS)
/* Repeatedly perform a read call until the buffer is filled */
/* up, or we encounter EOF or an error. */
STATIC ssize_t GC_repeat_read(int fd, char *buf, size_t count)
{
ssize_t num_read = 0;
ASSERT_CANCEL_DISABLED();
while ((size_t)num_read < count) {
ssize_t result = PROC_READ(fd, buf + num_read,
count - (size_t)num_read);
if (result < 0) return result;
if (result == 0) break;
num_read += result;
}
return num_read;
}
#endif /* LINUX_STACKBOTTOM || NEED_PROC_MAPS */
#ifdef NEED_PROC_MAPS
/* 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. */
#ifdef THREADS
/* Determine the length of a file by incrementally reading it into a */
/* buffer. This would be silly to use it on a file supporting lseek, */
/* but Linux /proc files usually do not. */
/* As of Linux 4.15.0, lseek(SEEK_END) fails for /proc/self/maps. */
STATIC size_t GC_get_file_len(int f)
{
size_t total = 0;
ssize_t result;
# define GET_FILE_LEN_BUF_SZ 500
char buf[GET_FILE_LEN_BUF_SZ];
do {
result = PROC_READ(f, buf, sizeof(buf));
if (result == -1) return 0;
total += (size_t)result;
} while (result > 0);
return total;
}
STATIC size_t GC_get_maps_len(void)
{
int f = open("/proc/self/maps", O_RDONLY);
size_t result;
if (f < 0) return 0; /* treat missing file as empty */
result = GC_get_file_len(f);
close(f);
return result;
}
#endif /* THREADS */
/* Copy the contents of /proc/self/maps to a buffer in our address */
/* space. Return the address of the buffer. */
GC_INNER const char * GC_get_maps(void)
{
ssize_t result;
static char *maps_buf = NULL;
static size_t maps_buf_sz = 1;
size_t maps_size;
# ifdef THREADS
size_t old_maps_size = 0;
# endif
/* The buffer is essentially static, so there must be a single client. */
GC_ASSERT(I_HOLD_LOCK());
/* Note that in the presence of threads, the maps file can */
/* essentially shrink asynchronously and unexpectedly as */
/* threads that we already think of as dead release their */
/* stacks. And there is no easy way to read the entire */
/* file atomically. This is arguably a misfeature of the */
/* /proc/self/maps interface. */
/* Since we expect the file can grow asynchronously in rare */
/* cases, it should suffice to first determine */
/* the size (using read), and then to reread the file. */
/* If the size is inconsistent we have to retry. */
/* This only matters with threads enabled, and if we use */
/* this to locate roots (not the default). */
# ifdef THREADS
/* Determine the initial size of /proc/self/maps. */
maps_size = GC_get_maps_len();
if (0 == maps_size)
ABORT("Cannot determine length of /proc/self/maps");
# else
maps_size = 4000; /* Guess */
# endif
/* Read /proc/self/maps, growing maps_buf as necessary. */
/* Note that we may not allocate conventionally, and */
/* thus can't use stdio. */
do {
int f;
while (maps_size >= maps_buf_sz) {
# ifdef LINT2
/* Workaround passing tainted maps_buf to a tainted sink. */
GC_noop1_ptr(maps_buf);
# else
GC_scratch_recycle_no_gww(maps_buf, maps_buf_sz);
# endif
/* 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 (NULL == maps_buf)
ABORT_ARG1("Insufficient space for /proc/self/maps buffer",
", %lu bytes requested", (unsigned long)maps_buf_sz);
# ifdef THREADS
/* Recompute initial length, since we allocated. */
/* This can only happen a few times per program */
/* execution. */
maps_size = GC_get_maps_len();
if (0 == maps_size)
ABORT("Cannot determine length of /proc/self/maps");
# endif
}
GC_ASSERT(maps_buf_sz >= maps_size + 1);
f = open("/proc/self/maps", O_RDONLY);
if (-1 == f)
ABORT_ARG1("Cannot open /proc/self/maps",
": errno= %d", errno);
# ifdef THREADS
old_maps_size = maps_size;
# endif
maps_size = 0;
do {
result = GC_repeat_read(f, maps_buf, maps_buf_sz-1);
if (result < 0) {
ABORT_ARG1("Failed to read /proc/self/maps",
": errno= %d", errno);
}
maps_size += (size_t)result;
} while ((size_t)result == maps_buf_sz-1);
close(f);
if (0 == maps_size)
ABORT("Empty /proc/self/maps");
# ifdef THREADS
if (maps_size > old_maps_size) {
/* This might be caused by e.g. thread creation. */
WARN("Unexpected asynchronous /proc/self/maps growth"
" (to %" WARN_PRIuPTR " bytes)\n", maps_size);
}
# endif
} while (maps_size >= maps_buf_sz
# ifdef THREADS
|| maps_size < old_maps_size
# endif
);
maps_buf[maps_size] = '\0';
return maps_buf;
}
/*
* 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 august 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 maps_ptr to (*start), */
/* (*end), (*prot), (*maj_dev) and (*mapping_name). mapping_name may */
/* be NULL. (*prot) and (*mapping_name) are assigned pointers into the */
/* original buffer. */
#if defined(DYNAMIC_LOADING) && defined(USE_PROC_FOR_LIBRARIES) \
|| defined(IA64) || defined(INCLUDE_LINUX_THREAD_DESCR) \
|| (defined(CHECK_SOFT_VDB) && defined(MPROTECT_VDB)) \
|| (defined(REDIRECT_MALLOC) && defined(GC_LINUX_THREADS))
GC_INNER const char *GC_parse_map_entry(const char *maps_ptr,
ptr_t *start, ptr_t *end,
const char **prot, unsigned *maj_dev,
const char **mapping_name)
{
const unsigned char *start_start, *end_start, *maj_dev_start;
const unsigned char *p; /* unsigned for isspace, isxdigit */
if (maps_ptr == NULL || *maps_ptr == '\0') {
return NULL;
}
p = (const unsigned char *)maps_ptr;
while (isspace(*p)) ++p;
start_start = p;
GC_ASSERT(isxdigit(*start_start));
*start = (ptr_t)strtoul((const char *)start_start, (char **)&p, 16);
GC_ASSERT(*p=='-');
++p;
end_start = p;
GC_ASSERT(isxdigit(*end_start));
*end = (ptr_t)strtoul((const char *)end_start, (char **)&p, 16);
GC_ASSERT(isspace(*p));
while (isspace(*p)) ++p;
GC_ASSERT(*p == 'r' || *p == '-');
*prot = (const char *)p;
/* 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((const char *)maj_dev_start, NULL, 16);
if (mapping_name != NULL) {
while (*p && *p != '\n' && *p != '/' && *p != '[') p++;
*mapping_name = (const char *)p;
}
while (*p && *p++ != '\n');
return (const char *)p;
}
#endif /* REDIRECT_MALLOC || DYNAMIC_LOADING || IA64 || ... */
#if defined(IA64) || defined(INCLUDE_LINUX_THREAD_DESCR) \
|| (defined(CHECK_SOFT_VDB) && defined(MPROTECT_VDB))
/* Try to read the backing store base from /proc/self/maps. */
/* Return the bounds of the writable mapping with a 0 major device, */
/* which includes the address passed as data. */
/* Return FALSE if there is no such mapping. */
GC_INNER GC_bool GC_enclosing_writable_mapping(ptr_t addr, ptr_t *startp,
ptr_t *endp)
{
const char *prot;
ptr_t my_start, my_end;
const char *maps_ptr;
unsigned maj_dev;
GC_ASSERT(I_HOLD_LOCK());
maps_ptr = GC_get_maps();
for (;;) {
maps_ptr = GC_parse_map_entry(maps_ptr, &my_start, &my_end,
&prot, &maj_dev, 0);
if (NULL == maps_ptr) break;
if (ADDR_INSIDE(addr, my_start, my_end)) {
if (prot[1] != 'w' || maj_dev != 0) break;
*startp = my_start;
*endp = my_end;
return TRUE;
}
}
return FALSE;
}
#endif /* IA64 || INCLUDE_LINUX_THREAD_DESCR */
#if defined(REDIRECT_MALLOC) && defined(GC_LINUX_THREADS)
/* Find the text(code) mapping for the library whose name, after */
/* stripping the directory part, starts with nm. */
GC_INNER GC_bool GC_text_mapping(const char *nm, ptr_t *startp, ptr_t *endp)
{
size_t nm_len;
const char *prot, *map_path;
ptr_t my_start, my_end;
unsigned int maj_dev;
const char *maps_ptr;
GC_ASSERT(I_HOLD_LOCK());
maps_ptr = GC_get_maps();
nm_len = strlen(nm);
for (;;) {
maps_ptr = GC_parse_map_entry(maps_ptr, &my_start, &my_end,
&prot, &maj_dev, &map_path);
if (NULL == maps_ptr) break;
if (prot[0] == 'r' && prot[1] == '-' && prot[2] == 'x') {
const char *p = map_path;
/* Set p to point just past last slash, if any. */
while (*p != '\0' && *p != '\n' && *p != ' ' && *p != '\t') ++p;
while (ADDR_GE((ptr_t)p, (ptr_t)map_path) && *p != '/') --p;
++p;
if (strncmp(nm, p, nm_len) == 0) {
*startp = my_start;
*endp = my_end;
return TRUE;
}
}
}
return FALSE;
}
#endif /* REDIRECT_MALLOC */
#ifdef IA64
static ptr_t backing_store_base_from_proc(void)
{
ptr_t my_start, my_end;
GC_ASSERT(I_HOLD_LOCK());
if (!GC_enclosing_writable_mapping(GC_save_regs_in_stack(),
&my_start, &my_end)) {
GC_COND_LOG_PRINTF("Failed to find backing store base from /proc\n");
return 0;
}
return my_start;
}
#endif
#endif /* NEED_PROC_MAPS */
#if defined(SEARCH_FOR_DATA_START)
/* The i686 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. */
# if defined(LINUX) || defined(HURD)
/* 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, preferring __data_start.*/
/* We assume gcc-compatible pragmas. */
EXTERN_C_BEGIN
# pragma weak __data_start
# pragma weak data_start
extern int __data_start[], data_start[];
EXTERN_C_END
# elif defined(NETBSD)
EXTERN_C_BEGIN
extern char **environ;
EXTERN_C_END
# endif
ptr_t GC_data_start = NULL;
GC_INNER void GC_init_linux_data_start(void)
{
ptr_t data_end = DATAEND;
# if (defined(LINUX) || defined(HURD)) && defined(USE_PROG_DATA_START)
/* Try the easy approaches first: */
/* However, this may lead to wrong data start value if libgc */
/* code is put into a shared library (directly or indirectly) */
/* which is linked with -Bsymbolic-functions option. Thus, */
/* the following is not used by default. */
if (COVERT_DATAFLOW(ADDR(__data_start)) != 0) {
GC_data_start = (ptr_t)(__data_start);
} else {
GC_data_start = (ptr_t)(data_start);
}
if (COVERT_DATAFLOW(ADDR(GC_data_start)) != 0) {
if (ADDR_LT(data_end, GC_data_start))
ABORT_ARG2("Wrong __data_start/_end pair",
": %p .. %p", (void *)GC_data_start, (void *)data_end);
return;
}
# ifdef DEBUG_ADD_DEL_ROOTS
GC_log_printf("__data_start not provided\n");
# endif
# endif /* LINUX */
if (GC_no_dls) {
/* Not needed, avoids the SIGSEGV caused by */
/* GC_find_limit which complicates debugging. */
GC_data_start = data_end; /* set data root size to 0 */
return;
}
# ifdef NETBSD
/* This may need to be environ, without the underscore, for */
/* some versions. */
GC_data_start = (ptr_t)GC_find_limit(&environ, FALSE);
# else
GC_data_start = (ptr_t)GC_find_limit(data_end, FALSE);
# endif
}
#endif /* SEARCH_FOR_DATA_START */
#ifdef ECOS
# ifndef ECOS_GC_MEMORY_SIZE
# define ECOS_GC_MEMORY_SIZE (448 * 1024)
# endif /* ECOS_GC_MEMORY_SIZE */
/* TODO: 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 ecos_gc_memory[ECOS_GC_MEMORY_SIZE];
static ptr_t ecos_gc_brk = ecos_gc_memory;
static void *tiny_sbrk(ptrdiff_t increment)
{
void *p = ecos_gc_brk;
ecos_gc_brk += increment;
if (ADDR_LT((ptr_t)ecos_gc_memory + sizeof(ecos_gc_memory), ecos_gc_brk)) {
ecos_gc_brk -= increment;
return NULL;
}
return p;
}
# define sbrk tiny_sbrk
#endif /* ECOS */
#if defined(ADDRESS_SANITIZER) && (defined(UNIX_LIKE) \
|| defined(NEED_FIND_LIMIT) || defined(MPROTECT_VDB)) \
&& !defined(CUSTOM_ASAN_DEF_OPTIONS)
EXTERN_C_BEGIN
GC_API const char *__asan_default_options(void);
EXTERN_C_END
/* To tell ASan to allow GC to use its own SIGBUS/SEGV handlers. */
/* The function is exported just to be visible to ASan library. */
GC_API const char *__asan_default_options(void)
{
return "allow_user_segv_handler=1";
}
#endif
#ifdef OPENBSD
static struct sigaction old_segv_act;
STATIC JMP_BUF GC_jmp_buf_openbsd;
STATIC void GC_fault_handler_openbsd(int sig)
{
UNUSED_ARG(sig);
LONGJMP(GC_jmp_buf_openbsd, 1);
}
static volatile int firstpass;
/* Return first addressable location > p or bound. */
STATIC ptr_t GC_skip_hole_openbsd(ptr_t p, ptr_t bound)
{
static volatile ptr_t result;
struct sigaction act;
size_t pgsz;
GC_ASSERT(I_HOLD_LOCK());
pgsz = (size_t)sysconf(_SC_PAGESIZE);
GC_ASSERT(ADDR(bound) >= (word)pgsz);
act.sa_handler = GC_fault_handler_openbsd;
sigemptyset(&act.sa_mask);
act.sa_flags = SA_NODEFER | SA_RESTART;
/* act.sa_restorer is deprecated and should not be initialized. */
sigaction(SIGSEGV, &act, &old_segv_act);
firstpass = 1;
result = PTR_ALIGN_DOWN(p, pgsz);
if (SETJMP(GC_jmp_buf_openbsd) != 0 || firstpass) {
firstpass = 0;
if (ADDR_GE(result, bound - pgsz)) {
result = bound;
} else {
result = result + pgsz;
/* no overflow expected; do not use compound */
/* assignment with volatile-qualified left operand */
GC_noop1((word)(unsigned char)(*result));
}
}
sigaction(SIGSEGV, &old_segv_act, 0);
return result;
}
#endif /* OPENBSD */
#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_DOSERRORS
# define INCL_DOSEXCEPTIONS
# define INCL_DOSFILEMGR
# define INCL_DOSMEMMGR
# define INCL_DOSMISC
# define INCL_DOSMODULEMGR
# define INCL_DOSPROCESS
# include <os2.h>
#endif /* OS2 */
/* Find the page size. */
GC_INNER size_t GC_page_size = 0;
#ifdef REAL_PAGESIZE_NEEDED
GC_INNER size_t GC_real_page_size = 0;
#endif
#ifdef SOFT_VDB
STATIC unsigned GC_log_pagesize = 0;
#endif
#ifdef ANY_MSWIN
# ifndef VER_PLATFORM_WIN32_CE
# define VER_PLATFORM_WIN32_CE 3
# endif
# if defined(MSWINCE) && defined(THREADS)
GC_INNER GC_bool GC_dont_query_stack_min = FALSE;
# endif
GC_INNER SYSTEM_INFO GC_sysinfo;
# ifndef CYGWIN32
# 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. */
STATIC 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 & ~(word)(PAGE_GUARD | PAGE_NOCACHE);
if (!is_writable(protect) || buf.State != MEM_COMMIT) return 0;
return buf.RegionSize;
}
/* Fill in the GC_stack_base structure with the stack bottom for */
/* this thread. Should not acquire the allocator lock as the */
/* function is used by GC_DllMain. */
GC_API int GC_CALL GC_get_stack_base(struct GC_stack_base *sb)
{
ptr_t trunc_sp;
word size;
/* Set page size if it is not ready (so client can use this */
/* function even before GC is initialized). */
if (!GC_page_size) GC_setpagesize();
trunc_sp = PTR_ALIGN_DOWN(GC_approx_sp(), GC_page_size);
/* FIXME: This won't work if called from a deeply recursive */
/* client code (and the committed stack space has grown). */
size = GC_get_writable_length(trunc_sp, 0);
GC_ASSERT(size != 0);
sb -> mem_base = trunc_sp + size;
return GC_SUCCESS;
}
# else /* CYGWIN32 */
/* An alternate version for Cygwin (adapted from Dave Korn's */
/* gcc version of boehm-gc). */
GC_API int GC_CALL GC_get_stack_base(struct GC_stack_base *sb)
{
# ifdef X86_64
sb -> mem_base = ((NT_TIB*)NtCurrentTeb())->StackBase;
# else
void * _tlsbase;
__asm__ ("movl %%fs:4, %0"
: "=r" (_tlsbase));
sb -> mem_base = _tlsbase;
# endif
return GC_SUCCESS;
}
# endif /* CYGWIN32 */
# define HAVE_GET_STACK_BASE
#elif defined(OS2)
static int os2_getpagesize(void)
{
ULONG result[1];
if (DosQuerySysInfo(QSV_PAGE_SIZE, QSV_PAGE_SIZE,
(void *)result, sizeof(ULONG)) != NO_ERROR) {
WARN("DosQuerySysInfo failed\n", 0);
result[0] = 4096;
}
return (int)result[0];
}
#endif /* !ANY_MSWIN && OS2 */
GC_INNER void GC_setpagesize(void)
{
# ifdef ANY_MSWIN
GetSystemInfo(&GC_sysinfo);
# ifdef ALT_PAGESIZE_USED
/* Allocations made with mmap() are aligned to the allocation */
/* granularity, which (at least on Win64) is not the same as the */
/* page size. Probably we could distinguish the allocation */
/* granularity from the actual page size, but in practice there */
/* is no good reason to make allocations smaller than */
/* dwAllocationGranularity, so we just use it instead of the */
/* actual page size here (as Cygwin itself does in many cases). */
GC_page_size = (size_t)GC_sysinfo.dwAllocationGranularity;
# ifdef REAL_PAGESIZE_NEEDED
GC_real_page_size = (size_t)GC_sysinfo.dwPageSize;
GC_ASSERT(GC_page_size >= GC_real_page_size);
# endif
# else
GC_page_size = (size_t)GC_sysinfo.dwPageSize;
# endif
# if defined(MSWINCE) && !defined(_WIN32_WCE_EMULATION)
{
OSVERSIONINFO verInfo;
/* Check the current WinCE version. */
verInfo.dwOSVersionInfoSize = sizeof(OSVERSIONINFO);
if (!GetVersionEx(&verInfo))
ABORT("GetVersionEx failed");
if (verInfo.dwPlatformId == VER_PLATFORM_WIN32_CE &&
verInfo.dwMajorVersion < 6) {
/* Only the first 32 MB of address space belongs to the */
/* current process (unless WinCE 6.0+ or emulation). */
GC_sysinfo.lpMaximumApplicationAddress = (LPVOID)((word)32 << 20);
# ifdef THREADS
/* On some old WinCE versions, it's observed that */
/* VirtualQuery calls don't work properly when used to */
/* get thread current stack committed minimum. */
if (verInfo.dwMajorVersion < 5)
GC_dont_query_stack_min = TRUE;
# endif
}
}
# endif
# else
# ifdef ALT_PAGESIZE_USED
# ifdef REAL_PAGESIZE_NEEDED
GC_real_page_size = (size_t)GETPAGESIZE();
# endif
/* It's acceptable to fake it. */
GC_page_size = HBLKSIZE;
# else
GC_page_size = (size_t)GETPAGESIZE();
# if !defined(CPPCHECK)
if (0 == GC_page_size)
ABORT("getpagesize failed");
# endif
# endif
# endif /* !ANY_MSWIN */
# ifdef SOFT_VDB
{
size_t pgsize;
unsigned log_pgsize = 0;
# if !defined(CPPCHECK)
if (((GC_page_size-1) & GC_page_size) != 0)
ABORT("Invalid page size"); /* not a power of two */
# endif
for (pgsize = GC_page_size; pgsize > 1; pgsize >>= 1)
log_pgsize++;
GC_log_pagesize = log_pgsize;
}
# endif
}
#ifdef EMBOX
# include <kernel/thread/thread_stack.h>
# include <pthread.h>
GC_API int GC_CALL GC_get_stack_base(struct GC_stack_base *sb)
{
pthread_t self = pthread_self();
void *stack_addr = thread_stack_get(self);
/* TODO: use pthread_getattr_np, pthread_attr_getstack alternatively */
# ifdef STACK_GROWS_UP
sb -> mem_base = stack_addr;
# else
sb -> mem_base = (ptr_t)stack_addr + thread_stack_get_size(self);
# endif
return GC_SUCCESS;
}
# define HAVE_GET_STACK_BASE
#endif /* EMBOX */
#ifdef HAIKU
# include <kernel/OS.h>
GC_API int GC_CALL GC_get_stack_base(struct GC_stack_base *sb)
{
thread_info th;
get_thread_info(find_thread(NULL),&th);
sb->mem_base = th.stack_end;
return GC_SUCCESS;
}
# define HAVE_GET_STACK_BASE
#endif /* HAIKU */
#ifdef OS2
GC_API int GC_CALL GC_get_stack_base(struct GC_stack_base *sb)
{
PTIB ptib; /* thread information block */
PPIB ppib;
if (DosGetInfoBlocks(&ptib, &ppib) != NO_ERROR) {
WARN("DosGetInfoBlocks failed\n", 0);
return GC_UNIMPLEMENTED;
}
sb->mem_base = ptib->tib_pstacklimit;
return GC_SUCCESS;
}
# define HAVE_GET_STACK_BASE
#endif /* OS2 */
#ifdef AMIGA
# define GC_AMIGA_SB
# include "extra/AmigaOS.c"
# undef GC_AMIGA_SB
# define GET_MAIN_STACKBASE_SPECIAL
#endif /* AMIGA */
#if defined(NEED_FIND_LIMIT) \
|| (defined(UNIX_LIKE) && !defined(NO_DEBUGGING)) \
|| (defined(USE_PROC_FOR_LIBRARIES) && defined(THREADS)) \
|| (defined(WRAP_MARK_SOME) && defined(NO_SEH_AVAILABLE))
# include <signal.h>
# ifdef USE_SEGV_SIGACT
# ifndef OPENBSD
static struct sigaction old_segv_act;
# endif
# ifdef USE_BUS_SIGACT
static struct sigaction old_bus_act;
# endif
# else
static GC_fault_handler_t old_segv_hand;
# ifdef HAVE_SIGBUS
static GC_fault_handler_t old_bus_hand;
# endif
# endif /* !USE_SEGV_SIGACT */
GC_INNER void GC_set_and_save_fault_handler(GC_fault_handler_t h)
{
# ifdef USE_SEGV_SIGACT
struct sigaction act;
act.sa_handler = h;
# ifdef SIGACTION_FLAGS_NODEFER_HACK
/* 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);
/* act.sa_restorer is deprecated and should not be initialized. */
# 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);
# else
(void)sigaction(SIGSEGV, &act, &old_segv_act);
# ifdef USE_BUS_SIGACT
/* 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_hand = signal(SIGSEGV, h);
# ifdef HAVE_SIGBUS
old_bus_hand = signal(SIGBUS, h);
# endif
# endif /* !USE_SEGV_SIGACT */
# if defined(CPPCHECK) && defined(ADDRESS_SANITIZER)
GC_noop1((word)(GC_funcptr_uint)&__asan_default_options);
# endif
}
#endif /* NEED_FIND_LIMIT || UNIX_LIKE || WRAP_MARK_SOME */
#if defined(NEED_FIND_LIMIT) \
|| (defined(USE_PROC_FOR_LIBRARIES) && defined(THREADS)) \
|| (defined(WRAP_MARK_SOME) && defined(NO_SEH_AVAILABLE))
GC_INNER JMP_BUF GC_jmp_buf;
STATIC void GC_fault_handler(int sig)
{
UNUSED_ARG(sig);
LONGJMP(GC_jmp_buf, 1);
}
GC_INNER void GC_setup_temporary_fault_handler(void)
{
/* Handler is process-wide, so this should only happen in */
/* one thread at a time. */
GC_ASSERT(I_HOLD_LOCK());
GC_set_and_save_fault_handler(GC_fault_handler);
}
GC_INNER void GC_reset_fault_handler(void)
{
# ifdef USE_SEGV_SIGACT
(void)sigaction(SIGSEGV, &old_segv_act, 0);
# ifdef USE_BUS_SIGACT
(void)sigaction(SIGBUS, &old_bus_act, 0);
# endif
# else
(void)signal(SIGSEGV, old_segv_hand);
# ifdef HAVE_SIGBUS
(void)signal(SIGBUS, old_bus_hand);
# endif
# endif
}
#endif /* NEED_FIND_LIMIT || USE_PROC_FOR_LIBRARIES || WRAP_MARK_SOME */
#if defined(NEED_FIND_LIMIT) \
|| (defined(USE_PROC_FOR_LIBRARIES) && defined(THREADS))
# define MIN_PAGE_SIZE 256 /* Smallest conceivable page size, in bytes. */
/* Return the first non-addressable 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. */
GC_ATTR_NO_SANITIZE_ADDR
STATIC ptr_t GC_find_limit_with_bound(ptr_t p, GC_bool up, ptr_t bound)
{
static volatile ptr_t result;
/* Safer if static, since otherwise it may not be */
/* preserved across the longjmp. Can safely be */
/* static since it's only called with the allocator */
/* lock held. */
GC_ASSERT(up ? ADDR(bound) >= MIN_PAGE_SIZE
: ADDR(bound) <= ~(word)MIN_PAGE_SIZE);
GC_ASSERT(I_HOLD_LOCK());
GC_setup_temporary_fault_handler();
if (SETJMP(GC_jmp_buf) == 0) {