apps: Add touch

apps/CMakeLists.txt

@@ -46,3 +46,4 @@ luna_app(socket-test.cpp socket-test)
 luna_app(socket-client.cpp socket-client)
 luna_app(input.cpp input)
 luna_app(shmem-test.cpp shmem-test)
+luna_app(touch.cpp touch)

apps/touch.cpp

@@ -0,0 +1,47 @@
+#include <errno.h>
+#include <os/ArgumentParser.h>
+#include <os/File.h>
+#include <sys/stat.h>
+
+Result<int> luna_main(int argc, char** argv)
+{
+    Vector<StringView> files;
+
+    bool only_atime { false };
+    bool only_mtime { false };
+    bool no_create { false };
+    bool no_dereference { false };
+
+    os::ArgumentParser parser;
+    parser.add_description("Update the access and modification times of files."_sv);
+    parser.add_system_program_info("touch"_sv);
+    parser.set_vector_argument(files, "files", true);
+    parser.add_switch_argument(only_atime, 'a', ""_sv, "change only the access time"_sv);
+    parser.add_switch_argument(no_create, 'c', "no-create"_sv, "do not create new files"_sv);
+    parser.add_switch_argument(no_dereference, 'h', "no-dereference"_sv, "do not follow symbolic links"_sv);
+    parser.add_switch_argument(only_mtime, 'm', ""_sv, "change only the modification time"_sv);
+    TRY(parser.parse(argc, argv));
+
+    if (only_atime && only_mtime)
+    {
+        os::eprintln("%s: only one of -a and -m can be specified.", argv[0]);
+        parser.short_usage(argv[0]);
+    }
+
+    struct timespec times[2] = {
+        { .tv_sec = 0, .tv_nsec = only_mtime ? UTIME_OMIT : UTIME_NOW },
+        { .tv_sec = 0, .tv_nsec = only_atime ? UTIME_OMIT : UTIME_NOW },
+    };
+
+    for (auto& filename : files)
+    {
+        SharedPtr<os::File> file;
+        if (no_create) file = TRY(os::File::open(filename, os::File::ReadOnly));
+        else
+            file = TRY(os::File::open_or_create(filename, os::File::ReadOnly));
+
+        if (futimens(file->fd(), times, no_dereference ? AT_SYMLINK_NOFOLLOW : 0) < 0) return err(errno);
+    }
+
+    return 0;
+}

kernel/src/sys/file.cpp

@@ -300,14 +300,20 @@ Result<u64> sys_utimensat(Registers*, SyscallArgs args)
     if (ktimes[0].tv_nsec != UTIME_OMIT)
     {
         if (ktimes[0].tv_nsec == UTIME_NOW) metadata.atime = *Timer::realtime_clock();
-        if (ktimes[0].tv_nsec < 0 || ktimes[0].tv_nsec > 999'999'999) return err(EINVAL);
-        metadata.atime = ktimes[0];
+        else
+        {
+            if (ktimes[0].tv_nsec < 0 || ktimes[0].tv_nsec > 999'999'999) return err(EINVAL);
+            metadata.atime = ktimes[0];
+        }
     }
     if (ktimes[1].tv_nsec != UTIME_OMIT)
     {
         if (ktimes[1].tv_nsec == UTIME_NOW) metadata.mtime = *Timer::realtime_clock();
-        if (ktimes[1].tv_nsec < 0 || ktimes[1].tv_nsec > 999'999'999) return err(EINVAL);
-        metadata.mtime = ktimes[1];
+        else
+        {
+            if (ktimes[1].tv_nsec < 0 || ktimes[1].tv_nsec > 999'999'999) return err(EINVAL);
+            metadata.mtime = ktimes[1];
+        }
     }
     TRY(inode->set_metadata(metadata));