commit 05b675e8bfec6e33138fd2e1b2e0e16afe745b37
author Elliott Hughes <enh@google.com> Wed Apr 17 13:01:06 2019 -0700
committer Elliott Hughes <enh@google.com> Fri Aug 02 09:09:59 2019 -0700
tree 2de2c98f748581531eaa6b0bb92adbe30f891f36
parent c2a722f5d77911afd199f452b03d9c15fbe645f8

Add renameat2.

Bug: http://b/127675384
Test: new tests
Change-Id: Ia2e3d5679180391ca98e62fa429fa11cbf167507

libc/SYSCALLS.TXT

diff --git a/libc/SYSCALLS.TXT b/libc/SYSCALLS.TXT
index 99bdc93..62d698f 100644
--- a/libc/SYSCALLS.TXT
+++ b/libc/SYSCALLS.TXT
@@ -151,6 +151,7 @@
 int mknodat(int, const char*, mode_t, dev_t)  all
 int readlinkat(int, const char*, char*, size_t)  all
 int renameat(int, const char*, int, const char*)  all
+int renameat2(int, const char*, int, const char*, unsigned)  all
 int symlinkat(const char*, int, const char*)  all
 int unlinkat(int, const char*, int)   all
 int utimensat(int, const char*, const struct timespec times[2], int)  all

libc/include/stdio.h

diff --git a/libc/include/stdio.h b/libc/include/stdio.h
index 8bd690f..6632c01 100644
--- a/libc/include/stdio.h
+++ b/libc/include/stdio.h
@@ -165,9 +165,53 @@
 char* tempnam(const char* __dir, const char* __prefix)
     __warnattr("tempnam is unsafe, use mkstemp or tmpfile instead");
 
+/**
+ * [rename(2)](http://man7.org/linux/man-pages/man2/rename.2.html) changes
+ * the name or location of a file.
+ *
+ * Returns 0 on success, and returns -1 and sets `errno` on failure.
+ */
 int rename(const char* __old_path, const char* __new_path);
+
+/**
+ * [renameat(2)](http://man7.org/linux/man-pages/man2/renameat.2.html) changes
+ * the name or location of a file, interpreting relative paths using an fd.
+ *
+ * Returns 0 on success, and returns -1 and sets `errno` on failure.
+ */
 int renameat(int __old_dir_fd, const char* __old_path, int __new_dir_fd, const char* __new_path);
 
+#if defined(__USE_GNU)
+
+/**
+ * Flag for [renameat2(2)](http://man7.org/linux/man-pages/man2/renameat2.2.html)
+ * to fail if the new path already exists.
+ */
+#define RENAME_NOREPLACE (1<<0)
+
+/**
+ * Flag for [renameat2(2)](http://man7.org/linux/man-pages/man2/renameat2.2.html)
+ * to atomically exchange the two paths.
+ */
+#define RENAME_EXCHANGE (1<<1)
+
+/**
+ * Flag for [renameat2(2)](http://man7.org/linux/man-pages/man2/renameat2.2.html)
+ * to create a union/overlay filesystem object.
+ */
+#define RENAME_WHITEOUT (1<<2)
+
+/**
+ * [renameat2(2)](http://man7.org/linux/man-pages/man2/renameat2.2.html) changes
+ * the name or location of a file, interpreting relative paths using an fd,
+ * with optional `RENAME_` flags.
+ *
+ * Returns 0 on success, and returns -1 and sets `errno` on failure.
+ */
+int renameat2(int __old_dir_fd, const char* __old_path, int __new_dir_fd, const char* __new_path, unsigned __flags) __INTRODUCED_IN(30);
+
+#endif
+
 int fseek(FILE* __fp, long __offset, int __whence);
 long ftell(FILE* __fp);
 

libc/libc.map.txt

diff --git a/libc/libc.map.txt b/libc/libc.map.txt
index 0cab83d..c3b9e2c 100644
--- a/libc/libc.map.txt
+++ b/libc/libc.map.txt
@@ -1503,6 +1503,7 @@
     pthread_mutex_clocklock;
     pthread_rwlock_clockrdlock;
     pthread_rwlock_clockwrlock;
+    renameat2;
     sem_clockwait;
     thrd_create;
     thrd_current;