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Diffstat (limited to 'libc')
-rw-r--r--libc/sysdeps/linux/common/dup2.c17
-rw-r--r--libc/sysdeps/linux/common/dup3.c1
2 files changed, 18 insertions, 0 deletions
diff --git a/libc/sysdeps/linux/common/dup2.c b/libc/sysdeps/linux/common/dup2.c
index 006f06b69..98ac4e305 100644
--- a/libc/sysdeps/linux/common/dup2.c
+++ b/libc/sysdeps/linux/common/dup2.c
@@ -9,7 +9,24 @@
#include <sys/syscall.h>
#include <unistd.h>
+#if defined __NR_dup3 && !defined __NR_dup2
+# include <fcntl.h>
+extern int __libc_fcntl (int fd, int cmd, ...);
+libc_hidden_proto(__libc_fcntl);
+int dup2(int old, int newfd)
+{
+ /*
+ * Check if old fd is valid before we try
+ * to ducplicate it. Return it if valid
+ * or EBADF otherwise
+ */
+ if (old == newfd)
+ return fcntl(old, F_GETFL, 0) < 0 ? -1 : newfd;
+ return dup3(old, newfd, 0);
+}
+#else
_syscall2(int, dup2, int, oldfd, int, newfd)
+#endif
libc_hidden_def(dup2)
diff --git a/libc/sysdeps/linux/common/dup3.c b/libc/sysdeps/linux/common/dup3.c
index 0472dd3be..5e8acdc8b 100644
--- a/libc/sysdeps/linux/common/dup3.c
+++ b/libc/sysdeps/linux/common/dup3.c
@@ -12,4 +12,5 @@
#if defined(__NR_dup3)
_syscall3(int, dup3, int, oldfd, int, newfd, int, flags)
+libc_hidden_def(dup3)
#endif