kernel: Add umask

apps/init.cpp

@@ -272,6 +272,8 @@ int main()
     stdout = fopen("/dev/console", "w");
     stderr = fopen("/dev/console", "w");
 
+    umask(022);
+
     g_init_log = fopen("/init.log", "w+");
     fcntl(fileno(g_init_log), F_SETFD, FD_CLOEXEC);
 

apps/mkdir.cpp

@@ -2,6 +2,14 @@
 #include <luna/PathParser.h>
 #include <os/ArgumentParser.h>
 #include <os/FileSystem.h>
+#include <sys/stat.h>
+
+static mode_t s_umask = 0;
+
+static void read_umask()
+{
+    s_umask = umask(0);
+}
 
 Result<void> mkdir_recursively(StringView path, mode_t mode)
 {
@@ -15,7 +23,7 @@ begin:
         PathParser parser = TRY(PathParser::create(path.chars()));
         auto parent = TRY(parser.dirname());
 
-        TRY(mkdir_recursively(parent.view(), mode));
+        TRY(mkdir_recursively(parent.view(), (0777 & ~s_umask) | S_IWUSR | S_IXUSR));
 
         goto begin;
     }
@@ -33,12 +41,18 @@ Result<int> luna_main(int argc, char** argv)
     parser.add_description("Create directories."_sv);
     parser.add_system_program_info("mkdir"_sv);
     parser.add_positional_argument(path, "path"_sv, true);
-    parser.add_positional_argument(mode_string, "mode"_sv, "755"_sv);
+    parser.add_value_argument(mode_string, 'm', "mode"_sv, true, "set the mode for the newly created directory");
     parser.add_switch_argument(recursive, 'p', "parents"_sv,
                                "if parent directories do not exist, create them as well"_sv);
     parser.parse(argc, argv);
 
-    mode_t mode = (mode_t)parse_unsigned_integer(mode_string.chars(), nullptr, 8);
+    read_umask();
+
+    mode_t mode;
+
+    if (mode_string.is_empty()) mode = 0777 & ~s_umask;
+    else
+        mode = (mode_t)parse_unsigned_integer(mode_string.chars(), nullptr, 8) & 01777;
 
     if (recursive)
     {

kernel/src/sys/exec.cpp

@@ -134,6 +134,7 @@ Result<u64> sys_fork(Registers* regs, SyscallArgs)
     thread->auth = current->auth;
     thread->current_directory = current->current_directory;
     thread->current_directory_path = move(current_directory_path);
+    thread->umask = current->umask;
     thread->parent = current;
 
     for (int i = 0; i < FD_MAX; i++)

kernel/src/sys/file.cpp

@@ -194,3 +194,16 @@ Result<u64> sys_pipe(Registers*, SyscallArgs args)
 
     return 0;
 }
+
+Result<u64> sys_umask(Registers*, SyscallArgs args)
+{
+    mode_t new_umask = (mode_t)args[0];
+
+    auto* current = Scheduler::current();
+
+    mode_t old_umask = current->umask;
+
+    current->umask = new_umask & 0777;
+
+    return old_umask;
+}

kernel/src/sys/mkdir.cpp

@@ -12,7 +12,7 @@ Result<u64> sys_mkdir(Registers*, SyscallArgs args)
     Thread* current = Scheduler::current();
 
     auto inode = TRY(VFS::create_directory(path.chars(), current->auth, current->current_directory));
-    inode->chmod(mode);
+    inode->chmod(mode & ~current->umask);
     inode->chown(current->auth.euid, current->auth.egid);
 
     return 0;

kernel/src/sys/open.cpp

@@ -38,7 +38,7 @@ Result<u64> sys_openat(Registers*, SyscallArgs args)
         if (error == ENOENT && (flags & O_CREAT) && !path.is_empty())
         {
             inode = TRY(VFS::create_file(path.chars(), current->auth, parent_inode));
-            inode->chmod(mode);
+            inode->chmod(mode & ~current->umask);
             inode->chown(current->auth.euid, current->auth.egid);
         }
         else

kernel/src/thread/Thread.h

@@ -87,6 +87,8 @@ struct Thread : public LinkedListNode<Thread>
 
     u8 status { 0 };
 
+    mode_t umask { 0 };
+
     StaticString<128> name;
 
     String current_directory_path = {};

libc/include/sys/stat.h

@@ -38,6 +38,9 @@ extern "C"
     /* Retrieve information about a file. */
     int fstatat(int dirfd, const char* path, struct stat* st, int flags);
 
+    /* Change the process's file creation mask. */
+    mode_t umask(mode_t mask);
+
 #ifdef __cplusplus
 }
 #endif

libc/src/sys/stat.cpp

@@ -47,4 +47,9 @@ extern "C"
         long rc = syscall(SYS_fstatat, dirfd, path, st, flags);
         __errno_return(rc, int);
     }
+
+    mode_t umask(mode_t mask)
+    {
+        return (mode_t)syscall(SYS_umask, mask);
+    }
 }

libluna/include/luna/Syscall.h

@@ -5,7 +5,7 @@
         _e(lseek) _e(mkdir) _e(execve) _e(fork) _e(waitpid) _e(getppid) _e(fcntl) _e(getdents) _e(getuid) _e(geteuid)  \
             _e(getgid) _e(getegid) _e(setuid) _e(setgid) _e(seteuid) _e(setegid) _e(fchmodat) _e(fchownat) _e(ioctl)   \
                 _e(fstatat) _e(chdir) _e(getcwd) _e(unlinkat) _e(uname) _e(sethostname) _e(dup2) _e(pipe) _e(mount)    \
-                    _e(umount) _e(pstat) _e(getrusage) _e(symlinkat) _e(readlinkat)
+                    _e(umount) _e(pstat) _e(getrusage) _e(symlinkat) _e(readlinkat) _e(umask)
 
 enum Syscalls
 {