@@ -2748,4 +2748,17 @@ struct target_sched_param {
abi_int sched_priority;
};
+/* from kernel's include/uapi/linux/openat2.h */
+struct target_open_how_ver0 {
+ abi_ullong flags;
+ abi_ullong mode;
+ abi_ullong resolve;
+};
+#ifndef RESOLVE_NO_MAGICLINKS
+#define RESOLVE_NO_MAGICLINKS 0x02
+#endif
+#ifndef RESOLVE_NO_SYMLINKS
+#define RESOLVE_NO_SYMLINKS 0x04
+#endif
+
#endif
@@ -602,6 +602,34 @@ static int check_zeroed_user(abi_long addr, size_t ksize, size_t usize)
return 1;
}
+/*
+ * Copies a target struct to a host struct, in a way that guarantees
+ * backwards-compatibility for struct syscall arguments.
+ *
+ * Similar to kernels uaccess.h:copy_struct_from_user()
+ */
+static int
+copy_struct_from_user(void *dst, size_t ksize, abi_ptr src, size_t usize)
+{
+ size_t size = MIN(ksize, usize);
+ size_t rest = MAX(ksize, usize) - size;
+
+ /* Deal with trailing bytes. */
+ if (usize < ksize) {
+ memset(dst + size, 0, rest);
+ } else if (usize > ksize) {
+ int ret = check_zeroed_user(src, ksize, usize);
+ if (ret <= 0) {
+ return ret ?: -TARGET_E2BIG;
+ }
+ }
+ /* Copy the interoperable parts of the struct. */
+ if (copy_from_user(dst, src, size)) {
+ return -TARGET_EFAULT;
+ }
+ return 0;
+}
+
#define safe_syscall0(type, name) \
static type safe_##name(void) \
{ \
@@ -653,6 +681,15 @@ safe_syscall3(ssize_t, read, int, fd, void *, buff, size_t, count)
safe_syscall3(ssize_t, write, int, fd, const void *, buff, size_t, count)
safe_syscall4(int, openat, int, dirfd, const char *, pathname, \
int, flags, mode_t, mode)
+
+struct open_how_ver0 {
+ __u64 flags;
+ __u64 mode;
+ __u64 resolve;
+};
+safe_syscall4(int, openat2, int, dirfd, const char *, pathname, \
+ const struct open_how_ver0 *, how, size_t, size)
+
#if defined(TARGET_NR_wait4) || defined(TARGET_NR_waitpid)
safe_syscall4(pid_t, wait4, pid_t, pid, int *, status, int, options, \
struct rusage *, rusage)
@@ -8332,8 +8369,9 @@ static int open_net_route(CPUArchState *cpu_env, int fd)
}
#endif
-int do_guest_openat(CPUArchState *cpu_env, int dirfd, const char *fname,
- int flags, mode_t mode, bool safe)
+static int maybe_do_fake_open(CPUArchState *cpu_env, int dirfd,
+ const char *fname, int flags, mode_t mode,
+ int openat2_resolve, bool safe)
{
g_autofree char *proc_name = NULL;
const char *pathname;
@@ -8370,6 +8408,12 @@ int do_guest_openat(CPUArchState *cpu_env, int dirfd, const char *fname,
}
if (is_proc_myself(pathname, "exe")) {
+ /* Honor openat2 resolve flags */
+ if ((openat2_resolve & RESOLVE_NO_MAGICLINKS) ||
+ (openat2_resolve & RESOLVE_NO_SYMLINKS)) {
+ errno = ELOOP;
+ return -1;
+ }
if (safe) {
return safe_openat(dirfd, exec_path, flags, mode);
} else {
@@ -8416,6 +8460,17 @@ int do_guest_openat(CPUArchState *cpu_env, int dirfd, const char *fname,
return fd;
}
+ return -2;
+}
+
+int do_guest_openat(CPUArchState *cpu_env, int dirfd, const char *pathname,
+ int flags, mode_t mode, bool safe)
+{
+ int fd = maybe_do_fake_open(cpu_env, dirfd, pathname, flags, mode, 0, safe);
+ if (fd > -2) {
+ return fd;
+ }
+
if (safe) {
return safe_openat(dirfd, path(pathname), flags, mode);
} else {
@@ -8423,6 +8478,49 @@ int do_guest_openat(CPUArchState *cpu_env, int dirfd, const char *fname,
}
}
+
+static int do_openat2(CPUArchState *cpu_env, abi_long dirfd,
+ abi_ptr guest_pathname, abi_ptr guest_open_how,
+ abi_ulong guest_size)
+{
+ struct open_how_ver0 how = {0};
+ char *pathname;
+ int ret;
+
+ if (guest_size < sizeof(struct target_open_how_ver0)) {
+ return -TARGET_EINVAL;
+ }
+ ret = copy_struct_from_user(&how, sizeof(how), guest_open_how, guest_size);
+ if (ret) {
+ if (ret == -TARGET_E2BIG) {
+ qemu_log_mask(LOG_UNIMP,
+ "Unimplemented openat2 open_how size: "
+ TARGET_ABI_FMT_lu "\n", guest_size);
+ }
+ return ret;
+ }
+ pathname = lock_user_string(guest_pathname);
+ if (!pathname) {
+ return -TARGET_EFAULT;
+ }
+
+ how.flags = target_to_host_bitmask(tswap64(how.flags), fcntl_flags_tbl);
+ how.mode = tswap64(how.mode);
+ how.resolve = tswap64(how.resolve);
+ int fd = maybe_do_fake_open(cpu_env, dirfd, pathname, how.flags, how.mode,
+ how.resolve, true);
+ if (fd > -2) {
+ ret = get_errno(fd);
+ } else {
+ ret = get_errno(safe_openat2(dirfd, pathname, &how,
+ sizeof(struct open_how_ver0)));
+ }
+
+ fd_trans_unregister(ret);
+ unlock_user(pathname, guest_pathname, 0);
+ return ret;
+}
+
ssize_t do_guest_readlink(const char *pathname, char *buf, size_t bufsiz)
{
ssize_t ret;
@@ -9195,6 +9293,9 @@ static abi_long do_syscall1(CPUArchState *cpu_env, int num, abi_long arg1,
fd_trans_unregister(ret);
unlock_user(p, arg2, 0);
return ret;
+ case TARGET_NR_openat2:
+ ret = do_openat2(cpu_env, arg1, arg2, arg3, arg4);
+ return ret;
#if defined(TARGET_NR_name_to_handle_at) && defined(CONFIG_OPEN_BY_HANDLE)
case TARGET_NR_name_to_handle_at:
ret = do_name_to_handle_at(arg1, arg2, arg3, arg4, arg5);