bsd-user: Implement stat related syscalls

Implement the following syscalls:
stat(2)
lstat(2)
fstat(2)
fstatat(2)
nstat
nfstat
nlstat

Signed-off-by: Stacey Son <sson@FreeBSD.org>
Signed-off-by: Karim Taha <kariem.taha2.7@gmail.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Warner Losh <imp@bsdimp.com>

bsd-user/freebsd/os-stat.h

+/*
+ *  stat related system call shims and definitions
+ *
+ *  Copyright (c) 2013 Stacey D. Son
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef BSD_USER_FREEBSD_OS_STAT_H
+#define BSD_USER_FREEBSD_OS_STAT_H
+
+/* stat(2) */
+static inline abi_long do_freebsd11_stat(abi_long arg1, abi_long arg2)
+{
+    abi_long ret;
+    void *p;
+    struct freebsd11_stat st;
+
+    LOCK_PATH(p, arg1);
+    ret = get_errno(freebsd11_stat(path(p), &st));
+    UNLOCK_PATH(p, arg1);
+    if (!is_error(ret)) {
+        ret = h2t_freebsd11_stat(arg2, &st);
+    }
+    return ret;
+}
+
+/* lstat(2) */
+static inline abi_long do_freebsd11_lstat(abi_long arg1, abi_long arg2)
+{
+    abi_long ret;
+    void *p;
+    struct freebsd11_stat st;
+
+    LOCK_PATH(p, arg1);
+    ret = get_errno(freebsd11_lstat(path(p), &st));
+    UNLOCK_PATH(p, arg1);
+    if (!is_error(ret)) {
+        ret = h2t_freebsd11_stat(arg2, &st);
+    }
+    return ret;
+}
+
+/* fstat(2) */
+static inline abi_long do_freebsd_fstat(abi_long arg1, abi_long arg2)
+{
+    abi_long ret;
+    struct stat st;
+
+    ret = get_errno(fstat(arg1, &st));
+    if (!is_error(ret))  {
+        ret = h2t_freebsd_stat(arg2, &st);
+    }
+    return ret;
+}
+
+/* fstatat(2) */
+static inline abi_long do_freebsd_fstatat(abi_long arg1, abi_long arg2,
+        abi_long arg3, abi_long arg4)
+{
+    abi_long ret;
+    void *p;
+    struct stat st;
+
+    LOCK_PATH(p, arg2);
+    ret = get_errno(fstatat(arg1, p, &st, arg4));
+    UNLOCK_PATH(p, arg2);
+    if (!is_error(ret) && arg3) {
+        ret = h2t_freebsd_stat(arg3, &st);
+    }
+    return ret;
+}
+
+/* undocummented nstat(char *path, struct nstat *ub) syscall */
+static abi_long do_freebsd11_nstat(abi_long arg1, abi_long arg2)
+{
+    abi_long ret;
+    void *p;
+    struct freebsd11_stat st;
+
+    LOCK_PATH(p, arg1);
+    ret = get_errno(freebsd11_nstat(path(p), &st));
+    UNLOCK_PATH(p, arg1);
+    if (!is_error(ret)) {
+        ret = h2t_freebsd11_nstat(arg2, &st);
+    }
+    return ret;
+}
+
+/* undocummented nfstat(int fd, struct nstat *sb) syscall */
+static abi_long do_freebsd11_nfstat(abi_long arg1, abi_long arg2)
+{
+    abi_long ret;
+    struct freebsd11_stat st;
+
+    ret = get_errno(freebsd11_nfstat(arg1, &st));
+    if (!is_error(ret))  {
+        ret = h2t_freebsd11_nstat(arg2, &st);
+    }
+    return ret;
+}
+
+/* undocummented nlstat(char *path, struct nstat *ub) syscall */
+static abi_long do_freebsd11_nlstat(abi_long arg1, abi_long arg2)
+{
+    abi_long ret;
+    void *p;
+    struct freebsd11_stat st;
+
+    LOCK_PATH(p, arg1);
+    ret = get_errno(freebsd11_nlstat(path(p), &st));
+    UNLOCK_PATH(p, arg1);
+    if (!is_error(ret)) {
+        ret = h2t_freebsd11_nstat(arg2, &st);
+    }
+    return ret;
+}
+
+#endif /* BSD_USER_FREEBSD_OS_STAT_H */