/**
* 使用当前JVM的jar包
*/
void FileMapInfo::populate_header(size_t alignment) {
_header._magic = 0xf00baba2;
_header._version = _current_version;
_header._alignment = alignment;
// The following fields are for sanity checks for whether this archive
// will function correctly with this JVM and the bootclasspath it's
// invoked with.
// JVM version string ... changes on each build.
const char *vm_version = VM_Version::internal_vm_info_string();
if (strlen(vm_version) < (JVM_IDENT_MAX-1)) {
strcpy(_header._jvm_ident, vm_version);
} else {
fail_stop("JVM Ident field for shared archive is too long"
" - truncated to <%s>", _header._jvm_ident);
}
// Build checks on classpath and jar files
_header._num_jars = 0;
ClassPathEntry *cpe = ClassLoader::classpath_entry(0);
for ( ; cpe != NULL; cpe = cpe->next()) {
if (cpe->is_jar_file()) { //jar包文件
if (_header._num_jars >= JVM_SHARED_JARS_MAX) {
fail_stop("Too many jar files to share.", NULL);
}
// Jar file - record timestamp and file size.
struct stat st;
const char *path = cpe->name();
if (os::stat(path, &st) != 0) {
// If we can't access a jar file in the boot path, then we can't
// make assumptions about where classes get loaded from.
fail_stop("Unable to open jar file %s.", path);
}
_header._jar[_header._num_jars]._timestamp = st.st_mtime;
_header._jar[_header._num_jars]._filesize = st.st_size;
_header._num_jars++;
} else {
// If directories appear in boot classpath, they must be empty to
// avoid having to verify each individual class file.
const char* name = ((ClassPathDirEntry*)cpe)->name();
if (!os::dir_is_empty(name)) {
fail_stop("Boot classpath directory %s is not empty.", name);
}
}
}
}
void FileMapInfo::unmap_region(int i) {
struct FileMapInfo::FileMapHeader::space_info* si = &_header._space[i];
size_t used = si->_used;
size_t size = align_size_up(used, os::vm_allocation_granularity());
if (!os::unmap_memory(si->_base, size)) {
fail_stop("Unable to unmap shared space.");
}
}
void FileMapInfo::close() {
if (_file_open) {
if (::close(_fd) < 0) {
fail_stop("Unable to close the shared archive file.");
}
_file_open = false;
_fd = -1;
}
}
void FileMapInfo::write_bytes(const void* buffer, int nbytes) {
if (_file_open) {
int n = ::write(_fd, buffer, nbytes);
if (n != nbytes) {
// It is dangerous to leave the corrupted shared archive file around,
// close and remove the file. See bug 6372906.
close();
remove(_full_path);
fail_stop("Unable to write to shared archive file.", NULL);
}
}
_file_offset += nbytes;
}
// Unmap mapped regions of shared space.
void FileMapInfo::stop_sharing_and_unmap(const char* msg) {
FileMapInfo *map_info = FileMapInfo::current_info();
if (map_info) {
map_info->fail_continue(msg);
for (int i = 0; i < MetaspaceShared::n_regions; i++) {
if (map_info->_header->_space[i]._base != NULL) {
map_info->unmap_region(i);
map_info->_header->_space[i]._base = NULL;
}
}
} else if (DumpSharedSpaces) {
fail_stop(msg, NULL);
}
}
void FileMapInfo::unmap_string_regions() {
for (int i = MetaspaceShared::first_string;
i < MetaspaceShared::first_string + MetaspaceShared::max_strings; i++) {
struct FileMapInfo::FileMapHeader::space_info* si = &_header->_space[i];
size_t used = si->_used;
if (used > 0) {
size_t size = align_size_up(used, os::vm_allocation_granularity());
char* addr = (char*)((void*)oopDesc::decode_heap_oop_not_null(
(narrowOop)si->_addr._offset));
if (!os::unmap_memory(addr, size)) {
fail_stop("Unable to unmap shared space.");
}
}
}
}
void FileMapInfo::unmap_region(int i) {
assert(!MetaspaceShared::is_string_region(i), "sanity");
struct FileMapInfo::FileMapHeader::space_info* si = &_header->_space[i];
size_t used = si->_used;
size_t size = align_size_up(used, os::vm_allocation_granularity());
if (used == 0) {
return;
}
char* addr = _header->region_addr(i);
if (!os::unmap_memory(addr, size)) {
fail_stop("Unable to unmap shared space.");
}
}
void FileMapInfo::align_file_position() {
long new_file_offset = align_size_up(_file_offset, os::vm_allocation_granularity());
if (new_file_offset != _file_offset) {
_file_offset = new_file_offset;
if (_file_open) {
// Seek one byte back from the target and write a byte to insure
// that the written file is the correct length.
_file_offset -= 1;
if (lseek(_fd, _file_offset, SEEK_SET) < 0) {
fail_stop("Unable to seek.", NULL);
}
char zero = 0;
write_bytes(&zero, 1);
}
}
}
// Unmap mapped regions of shared space.
void FileMapInfo::stop_sharing_and_unmap(const char* msg) {
FileMapInfo *map_info = FileMapInfo::current_info();
if (map_info) {
map_info->fail_continue("%s", msg);
for (int i = 0; i < MetaspaceShared::num_non_strings; i++) {
char *addr = map_info->_header->region_addr(i);
if (addr != NULL && !MetaspaceShared::is_string_region(i)) {
map_info->unmap_region(i);
map_info->_header->_space[i]._addr._base = NULL;
}
}
map_info->unmap_string_regions();
} else if (DumpSharedSpaces) {
fail_stop("%s", msg);
}
}
void FileMapInfo::open_for_write() {
_full_path = Arguments::GetSharedArchivePath();
if (PrintSharedSpaces) {
tty->print_cr("Dumping shared data to file: ");
tty->print_cr(" %s", _full_path);
}
// Remove the existing file in case another process has it open.
remove(_full_path);
int fd = open(_full_path, O_RDWR | O_CREAT | O_TRUNC | O_BINARY, 0444);
if (fd < 0) {
fail_stop("Unable to create shared archive file %s.", _full_path);
}
_fd = fd;
_file_offset = 0;
_file_open = true;
}
void FileMapInfo::open_for_write() {
_full_path = Arguments::GetSharedArchivePath();
if (PrintSharedSpaces) {
tty->print_cr("Dumping shared data to file: ");
tty->print_cr(" %s", _full_path);
}
#ifdef _WINDOWS // On Windows, need WRITE permission to remove the file.
chmod(_full_path, _S_IREAD | _S_IWRITE);
#endif
// Use remove() to delete the existing file because, on Unix, this will
// allow processes that have it open continued access to the file.
remove(_full_path);
int fd = open(_full_path, O_RDWR | O_CREAT | O_TRUNC | O_BINARY, 0444);
if (fd < 0) {
fail_stop("Unable to create shared archive file %s.", _full_path);
}
_fd = fd;
_file_offset = 0;
_file_open = true;
}
void FileMapInfo::assert_mark(bool check) {
if (!check) {
fail_stop("Mark mismatch while restoring from shared file.", NULL);
}
}