Merge "adb: win32: file descriptor reliability improvements" (feacf20d) · Commits · e / os / android_system_core

adb/sysdeps_win32.cpp

+27 −20

Original line number	Diff line number	Diff line
		@@ -203,7 +203,7 @@ typedef struct FHRec_

		static adb_mutex_t _win32_lock;
		static FHRec _win32_fhs[ WIN32_MAX_FHS ];
		static int _win32_fh_count;
		static int _win32_fh_next; // where to start search for free FHRec

		static FH
		_fh_from_int( int fd, const char* func )
		@@ -212,7 +212,7 @@ _fh_from_int( int fd, const char* func )

		fd -= WIN32_FH_BASE;

		if (fd < 0 \|\| fd >= _win32_fh_count) {
		if (fd < 0 \|\| fd >= WIN32_MAX_FHS) {
		D( "_fh_from_int: invalid fd %d passed to %s\n", fd + WIN32_FH_BASE,
		func );
		errno = EBADF;
		@@ -244,28 +244,32 @@ _fh_to_int( FH f )
		static FH
		_fh_alloc( FHClass clazz )
		{
		int nn;
		FH f = NULL;

		adb_mutex_lock( &_win32_lock );

		if (_win32_fh_count < WIN32_MAX_FHS) {
		f = &_win32_fhs[ _win32_fh_count++ ];
		goto Exit;
		}

		for (nn = 0; nn < WIN32_MAX_FHS; nn++) {
		if ( _win32_fhs[nn].clazz == NULL) {
		f = &_win32_fhs[nn];
		// Search entire array, starting from _win32_fh_next.
		for (int nn = 0; nn < WIN32_MAX_FHS; nn++) {
		// Keep incrementing _win32_fh_next to avoid giving out an index that
		// was recently closed, to try to avoid use-after-free.
		const int index = _win32_fh_next++;
		// Handle wrap-around of _win32_fh_next.
		if (_win32_fh_next == WIN32_MAX_FHS) {
		_win32_fh_next = 0;
		}
		if (_win32_fhs[index].clazz == NULL) {
		f = &_win32_fhs[index];
		goto Exit;
		}
		}
		D( "_fh_alloc: no more free file descriptors\n" );
		errno = EMFILE; // Too many open files
		Exit:
		if (f) {
		f->clazz = clazz;
		f->used = 1;
		f->eof = 0;
		f->name[0] = '\0';
		clazz->_fh_init(f);
		}
		adb_mutex_unlock( &_win32_lock );
		@@ -276,12 +280,17 @@ Exit:
		static int
		_fh_close( FH f )
		{
		// Use lock so that closing only happens once and so that _fh_alloc can't
		// allocate a FH that we're in the middle of closing.
		adb_mutex_lock(&_win32_lock);
		if (f->used) {
		f->clazz->_fh_close( f );
		f->used = 0;
		f->name[0] = '\0';
		f->eof = 0;
		f->used = 0;
		f->clazz = NULL;
		}
		adb_mutex_unlock(&_win32_lock);
		return 0;
		}

		@@ -404,7 +413,6 @@ int adb_open(const char* path, int options)

		f = _fh_alloc( &_fh_file_class );
		if ( !f ) {
		errno = ENOMEM;
		return -1;
		}

		@@ -446,7 +454,6 @@ int adb_creat(const char* path, int mode)

		f = _fh_alloc( &_fh_file_class );
		if ( !f ) {
		errno = ENOMEM;
		return -1;
		}