adb: create unix_isatty() function.
Our Windows code has several different ways it checks whether an FD is
a console or not, some of which aren't exactly correct as they may
treat character devices (e.g. NUL) as consoles.
This CL disallows using the builtin isatty() function and provides
unix_isatty() instead which correctly checks these corner cases.
Change-Id: I6d551c745dae691c7eb3446b585265d62c1e62fa
diff --git a/adb/sysdeps.h b/adb/sysdeps.h
index 51d09a6..1735627 100644
--- a/adb/sysdeps.h
+++ b/adb/sysdeps.h
@@ -181,6 +181,17 @@
extern int unix_open(const char* path, int options, ...);
#define open ___xxx_unix_open
+// Checks if |fd| corresponds to a console.
+// Standard Windows isatty() returns 1 for both console FDs and character
+// devices like NUL. unix_isatty() performs some extra checking to only match
+// console FDs.
+// |fd| must be a real file descriptor, meaning STDxx_FILENO or unix_open() FDs
+// will work but adb_open() FDs will not. Additionally the OS handle associated
+// with |fd| must have GENERIC_READ access (which console FDs have by default).
+// Returns 1 if |fd| is a console FD, 0 otherwise. The value of errno after
+// calling this function is unreliable and should not be used.
+int unix_isatty(int fd);
+#define isatty ___xxx_isatty
/* normally provided by <cutils/misc.h> */
extern void* load_file(const char* pathname, unsigned* psize);
@@ -551,6 +562,11 @@
#undef creat
#define creat ___xxx_creat
+static __inline__ int unix_isatty(int fd) {
+ return isatty(fd);
+}
+#define isatty ___xxx_isatty
+
// Helper for network_* functions.
inline int _fd_set_error_str(int fd, std::string* error) {
if (fd == -1) {