4 files changed, 12 insertions, 4 deletions
diff --git a/src/stat/fchmod.c b/src/stat/fchmod.c
index 1b943d44..6d281416 100644
--- a/src/stat/fchmod.c
+++ b/src/stat/fchmod.c
@@ -1,5 +1,6 @@
 #include <sys/stat.h>
 #include <errno.h>
+#include <fcntl.h>
 #include "syscall.h"
 
 void __procfdname(char *, unsigned);
@@ -7,7 +8,8 @@ void __procfdname(char *, unsigned);
 int fchmod(int fd, mode_t mode)
 {
 	int ret = __syscall(SYS_fchmod, fd, mode);
-	if (ret != -EBADF || fd < 0) return __syscall_ret(ret);
+	if (ret != -EBADF || __syscall(SYS_fcntl, fd, F_GETFD) < 0)
+		return __syscall_ret(ret);
 
 	char buf[15+3*sizeof(int)];
 	__procfdname(buf, fd);
diff --git a/src/stat/fstat.c b/src/stat/fstat.c
index 29b4243d..b5611767 100644
--- a/src/stat/fstat.c
+++ b/src/stat/fstat.c
@@ -1,5 +1,6 @@
 #include <sys/stat.h>
 #include <errno.h>
+#include <fcntl.h>
 #include "syscall.h"
 #include "libc.h"
 
@@ -8,7 +9,8 @@ void __procfdname(char *, unsigned);
 int fstat(int fd, struct stat *st)
 {
 	int ret = __syscall(SYS_fstat, fd, st);
-	if (ret != -EBADF || fd < 0) return __syscall_ret(ret);
+	if (ret != -EBADF || __syscall(SYS_fcntl, fd, F_GETFD) < 0)
+		return __syscall_ret(ret);
 
 	char buf[15+3*sizeof(int)];
 	__procfdname(buf, fd);
diff --git a/src/unistd/fchdir.c b/src/unistd/fchdir.c
index 9fbc8154..72c3915e 100644
--- a/src/unistd/fchdir.c
+++ b/src/unistd/fchdir.c
@@ -1,5 +1,6 @@
 #include <unistd.h>
 #include <errno.h>
+#include <fcntl.h>
 #include "syscall.h"
 
 void __procfdname(char *, unsigned);
@@ -7,7 +8,8 @@ void __procfdname(char *, unsigned);
 int fchdir(int fd)
 {
 	int ret = __syscall(SYS_fchdir, fd);
-	if (ret != -EBADF || fd < 0) return __syscall_ret(ret);
+	if (ret != -EBADF || __syscall(SYS_fcntl, fd, F_GETFD) < 0)
+		return __syscall_ret(ret);
 
 	char buf[15+3*sizeof(int)];
 	__procfdname(buf, fd);
diff --git a/src/unistd/fchown.c b/src/unistd/fchown.c
index e1c3198a..36633b0e 100644
--- a/src/unistd/fchown.c
+++ b/src/unistd/fchown.c
@@ -1,5 +1,6 @@
 #include <unistd.h>
 #include <errno.h>
+#include <fcntl.h>
 #include "syscall.h"
 
 void __procfdname(char *, unsigned);
@@ -7,7 +8,8 @@ void __procfdname(char *, unsigned);
 int fchown(int fd, uid_t uid, gid_t gid)
 {
 	int ret = __syscall(SYS_fchown, fd, uid, gid);
-	if (ret != -EBADF || fd < 0) return __syscall_ret(ret);
+	if (ret != -EBADF || __syscall(SYS_fcntl, fd, F_GETFD) < 0)
+		return __syscall_ret(ret);
 
 	char buf[15+3*sizeof(int)];
 	__procfdname(buf, fd);