4 files changed, 22 insertions, 3 deletions
diff --git a/src/unistd/faccessat.c b/src/unistd/faccessat.c
index 557503eb..43052dd7 100644
--- a/src/unistd/faccessat.c
+++ b/src/unistd/faccessat.c
@@ -53,7 +53,7 @@ int faccessat(int fd, const char *filename, int amode, int flag)
 	if (pid<0 || __syscall(SYS_read, p[0], &ret, sizeof ret) != sizeof(ret))
 		ret = -EBUSY;
 	__syscall(SYS_close, p[0]);
-	__syscall(SYS_wait4, pid, &status, __WCLONE, 0);
+	__sys_wait4(pid, &status, __WCLONE, 0);
 
 	__restore_sigs(&set);
 
diff --git a/src/unistd/pwrite.c b/src/unistd/pwrite.c
index 869b69f0..a008b3ec 100644
--- a/src/unistd/pwrite.c
+++ b/src/unistd/pwrite.c
@@ -1,7 +1,18 @@
+#define _GNU_SOURCE
 #include <unistd.h>
+#include <sys/uio.h>
+#include <fcntl.h>
 #include "syscall.h"
 
 ssize_t pwrite(int fd, const void *buf, size_t size, off_t ofs)
 {
+	if (ofs == -1) ofs--;
+	int r = __syscall_cp(SYS_pwritev2, fd,
+		(&(struct iovec){ .iov_base = (void *)buf, .iov_len = size }),
+		1, (long)(ofs), (long)(ofs>>32), RWF_NOAPPEND);
+	if (r != -EOPNOTSUPP && r != -ENOSYS)
+		return __syscall_ret(r);
+	if (fcntl(fd, F_GETFL) & O_APPEND)
+		return __syscall_ret(-EOPNOTSUPP);
 	return syscall_cp(SYS_pwrite, fd, buf, size, __SYSCALL_LL_PRW(ofs));
 }
diff --git a/src/unistd/pwritev.c b/src/unistd/pwritev.c
index becf9deb..44a53d85 100644
--- a/src/unistd/pwritev.c
+++ b/src/unistd/pwritev.c
@@ -1,10 +1,18 @@
-#define _BSD_SOURCE
+#define _GNU_SOURCE
 #include <sys/uio.h>
 #include <unistd.h>
+#include <fcntl.h>
 #include "syscall.h"
 
 ssize_t pwritev(int fd, const struct iovec *iov, int count, off_t ofs)
 {
+	if (ofs == -1) ofs--;
+	int r = __syscall_cp(SYS_pwritev2, fd, iov, count,
+		(long)(ofs), (long)(ofs>>32), RWF_NOAPPEND);
+	if (r != -EOPNOTSUPP && r != -ENOSYS)
+		return __syscall_ret(r);
+	if (fcntl(fd, F_GETFL) & O_APPEND)
+		return __syscall_ret(-EOPNOTSUPP);
 	return syscall_cp(SYS_pwritev, fd, iov, count,
 		(long)(ofs), (long)(ofs>>32));
 }
diff --git a/src/unistd/setxid.c b/src/unistd/setxid.c
index 487c1a16..a629ed4b 100644
--- a/src/unistd/setxid.c
+++ b/src/unistd/setxid.c
@@ -30,5 +30,5 @@ int __setxid(int nr, int id, int eid, int sid)
 	 * trigger the safety kill above. */
 	struct ctx c = { .nr = nr, .id = id, .eid = eid, .sid = sid, .ret = 1 };
 	__synccall(do_setxid, &c);
-	return __syscall_ret(c.ret);
+	return __syscall_ret(c.ret > 0 ? -EAGAIN : c.ret);
 }