Kernel+LibC: Unify sys$open() and sys$openat()

The syscall is now called sys$open(), but it behaves like the old sys$openat().
In userspace, open_with_path_length() is made a wrapper over openat_with_path_length().

Kernel/Process.cpp

@@ -1862,50 +1862,6 @@ int Process::sys$open(const Syscall::SC_open_params* user_params)
     if (!validate_read_and_copy_typed(&params, user_params))
         return -EFAULT;
 
-    auto options = params.options;
-    auto mode = params.mode;
-
-    if (options & O_NOFOLLOW_NOERROR)
-        return -EINVAL;
-
-    if ((options & O_RDWR) || (options & O_WRONLY))
-        REQUIRE_PROMISE(wpath);
-    else
-        REQUIRE_PROMISE(rpath);
-
-    if (options & O_CREAT)
-        REQUIRE_PROMISE(cpath);
-
-    auto path = get_syscall_path_argument(params.path);
-    if (path.is_error())
-        return path.error();
-
-    // Ignore everything except permission bits.
-    mode &= 04777;
-
-    int fd = alloc_fd();
-#ifdef DEBUG_IO
-    dbgprintf("%s(%u) sys$open(\"%s\") -> %d\n", name().characters(), pid(), path.value().characters(), fd);
-#endif
-    if (fd < 0)
-        return fd;
-    auto result = VFS::the().open(path.value(), options, mode & ~umask(), current_directory());
-    if (result.is_error())
-        return result.error();
-    auto description = result.value();
-    description->set_rw_mode(options);
-    description->set_file_flags(options);
-    u32 fd_flags = (options & O_CLOEXEC) ? FD_CLOEXEC : 0;
-    m_fds[fd].set(move(description), fd_flags);
-    return fd;
-}
-
-int Process::sys$openat(const Syscall::SC_openat_params* user_params)
-{
-    Syscall::SC_openat_params params;
-    if (!validate_read_and_copy_typed(&params, user_params))
-        return -EFAULT;
-
     int dirfd = params.dirfd;
     int options = params.options;
     u16 mode = params.mode;
@@ -1928,7 +1884,7 @@ int Process::sys$openat(const Syscall::SC_openat_params* user_params)
     if (path.is_error())
         return path.error();
 #ifdef DEBUG_IO
-    dbgprintf("%s(%u) sys$openat(%d, \"%s\")\n", dirfd, name().characters(), pid(), path.value().characters());
+    dbgprintf("%s(%u) sys$open(%d, \"%s\")\n", dirfd, name().characters(), pid(), path.value().characters());
 #endif
     int fd = alloc_fd();
     if (fd < 0)

Kernel/Process.h

@@ -145,7 +145,6 @@ public:
     pid_t sys$getppid();
     mode_t sys$umask(mode_t);
     int sys$open(const Syscall::SC_open_params*);
-    int sys$openat(const Syscall::SC_openat_params*);
     int sys$close(int fd);
     ssize_t sys$read(int fd, u8*, ssize_t);
     ssize_t sys$write(int fd, const u8*, ssize_t);

Kernel/Syscall.h

@@ -132,7 +132,6 @@ typedef u32 socklen_t;
     __ENUMERATE_SYSCALL(setkeymap)                  \
     __ENUMERATE_SYSCALL(clock_gettime)              \
     __ENUMERATE_SYSCALL(clock_nanosleep)            \
-    __ENUMERATE_SYSCALL(openat)                     \
     __ENUMERATE_SYSCALL(join_thread)                \
     __ENUMERATE_SYSCALL(module_load)                \
     __ENUMERATE_SYSCALL(module_unload)              \
@@ -218,12 +217,6 @@ struct SC_mmap_params {
 };
 
 struct SC_open_params {
-    StringArgument path;
-    int options;
-    u16 mode;
-};
-
-struct SC_openat_params {
     int dirfd;
     StringArgument path;
     int options;

Libraries/LibC/fcntl.cpp

@@ -33,17 +33,7 @@ int creat_with_path_length(const char* path, size_t path_length, mode_t mode)
 
 int open_with_path_length(const char* path, size_t path_length, int options, mode_t mode)
 {
-    if (!path) {
-        errno = EFAULT;
-        return -1;
-    }
-    if (path_length > INT32_MAX) {
-        errno = EINVAL;
-        return -1;
-    }
-    Syscall::SC_open_params params { { path, path_length }, options, mode };
-    int rc = syscall(SC_open, &params);
-    __RETURN_WITH_ERRNO(rc, rc, -1);
+    return openat_with_path_length(AT_FDCWD, path, path_length, options, mode);
 }
 
 int openat_with_path_length(int dirfd, const char* path, size_t path_length, int options, mode_t mode)
@@ -56,8 +46,8 @@ int openat_with_path_length(int dirfd, const char* path, size_t path_length, int
         errno = EINVAL;
         return -1;
     }
-    Syscall::SC_openat_params params { dirfd, { path, path_length }, options, mode };
-    int rc = syscall(SC_openat, &params);
+    Syscall::SC_open_params params { dirfd, { path, path_length }, options, mode };
+    int rc = syscall(SC_open, &params);
     __RETURN_WITH_ERRNO(rc, rc, -1);
 }