adb: move win32 fd base to 2048, fix fd allocation.
Windows has a maximum fd limit of 2048, so we can avoid collision with
real file descriptors by starting from there. Also, fds would be
previously be allocated by a linear walk from the last allocated FD,
instead of the lowest available FD, as required by POSIX. Keep track of
the lowest available file descriptor to make things feel more familiar.
Change-Id: Id6ac1c54f4f7964a6cdfa8d3f4f96262e4881964
diff --git a/sysdeps_win32.cpp b/sysdeps_win32.cpp
index 0dbfb98..c36d779 100644
--- a/sysdeps_win32.cpp
+++ b/sysdeps_win32.cpp
@@ -190,8 +190,7 @@
#define fh_handle u.handle
#define fh_socket u.socket
-#define WIN32_FH_BASE 100
-
+#define WIN32_FH_BASE 2048
#define WIN32_MAX_FHS 128
static adb_mutex_t _win32_lock;
@@ -241,17 +240,10 @@
adb_mutex_lock( &_win32_lock );
- // 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];
+ for (int i = _win32_fh_next; i < WIN32_MAX_FHS; ++i) {
+ if (_win32_fhs[i].clazz == NULL) {
+ f = &_win32_fhs[i];
+ _win32_fh_next = i + 1;
goto Exit;
}
}
@@ -276,6 +268,12 @@
// 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);
+
+ int offset = f - _win32_fhs;
+ if (_win32_fh_next > offset) {
+ _win32_fh_next = offset;
+ }
+
if (f->used) {
f->clazz->_fh_close( f );
f->name[0] = '\0';