.gitmodules

@@ -22,3 +22,6 @@
 [submodule "external/CLI11"]
 	path = external/CLI11
 	url = https://github.com/CLIUtils/CLI11.git
+[submodule "external/GSL"]
+	path = external/GSL
+	url = https://github.com/microsoft/GSL

CMakeLists.txt

@@ -247,6 +247,13 @@ include_from_source(cli11
   GIT_TAG v2.2.0
   )
 
+### GSL: Guidelines Support Library
+include_from_source(gsl
+	MESSAGE "[${PROJECT_NAME}] Searching for GSL"
+	SOURCE_DIR ${GKFS_DEPENDENCIES_PATH}/GSL
+  GIT_REPOSITORY https://github.com/microsoft/GSL
+  GIT_TAG v4.0.0
+  )
 
 ################################################################################
 ## Check configured variables/options and act accordingly

GSL @ a3534567

+Subproject commit a3534567187d2edc428efd3f13466ff75fe5805c

src/client/CMakeLists.txt

@@ -62,6 +62,7 @@ target_link_libraries(
          fmt::fmt
          Threads::Threads
          Date::TZ
+         Microsoft.GSL::GSL
 )
 
 install(
@@ -113,6 +114,7 @@ if(GKFS_ENABLE_FORWARDING)
            fmt::fmt
            Threads::Threads
            Date::TZ
+           Microsoft.GSL::GSL
   )
 
   install(

src/client/hooks.cpp

@@ -36,6 +36,7 @@
 #include <client/open_dir.hpp>
 
 #include <common/path_util.hpp>
+#include <gsl/gsl>
 
 #include <memory>
 
@@ -246,7 +247,7 @@ hook_pread(unsigned int fd, char* buf, size_t count, loff_t pos) {
     }
     /* Since kernel 2.6: pread() became pread64(), and pwrite() became
      * pwrite64(). */
-    return syscall_no_intercept_wrapper(SYS_pread64, fd, buf, count, pos);
+    return gsl::narrow<int>(syscall_no_intercept_wrapper(SYS_pread64, fd, buf, count, pos));
 }
 
 int
@@ -300,7 +301,7 @@ hook_pwrite(unsigned int fd, const char* buf, size_t count, loff_t pos) {
     }
     /* Since kernel 2.6: pread() became pread64(), and pwrite() became
      * pwrite64(). */
-    return syscall_no_intercept_wrapper(SYS_pwrite64, fd, buf, count, pos);
+    return gsl::narrow<int>(syscall_no_intercept_wrapper(SYS_pwrite64, fd, buf, count, pos));
 }
 
 int
@@ -602,7 +603,7 @@ hook_getdents64(unsigned int fd, struct linux_dirent64* dirp,
     if(CTX->file_map()->exist(fd)) {
         return with_errno(gkfs::syscall::gkfs_getdents64(fd, dirp, count));
     }
-    return syscall_no_intercept_wrapper(SYS_getdents64, fd, dirp, count);
+    return gsl::narrow<int>(syscall_no_intercept_wrapper(SYS_getdents64, fd, dirp, count));
 }