UserspaceEmulator: Implement set_process_name syscall

Userland/DevTools/UserspaceEmulator/Emulator.h

@@ -125,6 +125,7 @@ private:
     int virt$mkdir(FlatPtr path, size_t path_length, mode_t mode);
     int virt$unlink(FlatPtr path, size_t path_length);
     int virt$get_process_name(FlatPtr buffer, int size);
+    int virt$set_process_name(FlatPtr buffer, int size);
     int virt$set_mmap_name(FlatPtr);
     int virt$gettimeofday(FlatPtr);
     int virt$clock_gettime(int, FlatPtr);

Userland/DevTools/UserspaceEmulator/Emulator_syscalls.cpp

@@ -168,6 +168,8 @@ u32 Emulator::virt_syscall(u32 function, u32 arg1, u32 arg2, u32 arg3)
         return virt$getsockopt(arg1);
     case SC_get_process_name:
         return virt$get_process_name(arg1, arg2);
+    case SC_set_process_name:
+        return virt$set_process_name(arg1, arg2);
     case SC_dbgputstr:
         return virt$dbgputstr(arg1, arg2);
     case SC_dbgputch:
@@ -481,6 +483,15 @@ int Emulator::virt$get_process_name(FlatPtr buffer, int size)
     return rc;
 }
 
+int Emulator::virt$set_process_name(FlatPtr user_buffer, int size)
+{
+    if (size < 0)
+        return -EINVAL;
+    auto host_buffer = mmu().copy_buffer_from_vm(user_buffer, size);
+    auto name = String::formatted("(UE) {}", StringView { host_buffer.data(), host_buffer.size() });
+    return syscall(SC_set_process_name, name.characters(), name.length());
+}
+
 int Emulator::virt$lseek(int fd, off_t offset, int whence)
 {
     return syscall(SC_lseek, fd, offset, whence);