diff --git a/proj/server/src/intercept.py b/proj/server/src/intercept.py
index 2431243..b8a7b30 100755
--- a/proj/server/src/intercept.py
+++ b/proj/server/src/intercept.py
@@ -300,16 +300,21 @@ class Handler(StreamRequestHandler):
     def after_shm_unlink(self, name: PointerTo[bytes],
                          ret_value: int, errno: str = None) -> None:
         raise NotImplementedError()
-    def before_mmap(self, addr: Pointer, len_value: int, prot: Flags, flags: Flags, fildes: int, off: int) -> str:
+    def before_mmap(self, addr: Pointer, length: int, prot: Flags, flags: Flags, fildes: int, off: int) -> str:
         raise NotImplementedError()
-    def after_mmap(self, addr: Pointer, len_value: int, prot: Flags, flags: Flags, fildes: int, off: int,
+    def after_mmap(self, addr: Pointer, length: int, prot: Flags, flags: Flags, fildes: int, off: int,
                    ret_value: Pointer, errno: str = None) -> None:
         raise NotImplementedError()
-    def before_munmap(self, addr: Pointer, len_value: int) -> str:
+    def before_munmap(self, addr: Pointer, length: int) -> str:
         raise NotImplementedError()
-    def after_munmap(self, addr: Pointer, len_value: int,
+    def after_munmap(self, addr: Pointer, length: int,
                      ret_value: int, errno: str = None) -> None:
         raise NotImplementedError()
+    def before_ftruncate(self, fildes: int, length: int) -> str:
+        raise NotImplementedError()
+    def after_ftruncate(self, fildes: int, length: int,
+                        ret_value: int, errno: str = None) -> None:
+        raise NotImplementedError()
 
 
 class MemoryAllocationTester(Handler):
@@ -393,6 +398,7 @@ class InterruptedCheckTester(Handler):
         'sem_trywait': ('fail EINTR', 'return 0'),
         'sem_timedwait': ('fail EINTR', 'return 0'),
         'sem_post': (None, 'return 0'),
+        'ftruncate': ('fail EINTR', 'ok'),
     }
 
     counter: int = 0
diff --git a/proj/test1/Makefile b/proj/test1/Makefile
index 16edf24..892a803 100644
--- a/proj/test1/Makefile
+++ b/proj/test1/Makefile
@@ -27,7 +27,8 @@ main: bin/main.o
 main_intercept: bin/main.o src/intercept.c
 	$(CC) -o $@ $^ $(CFLAGS) -lc -Wl,--wrap=malloc,--wrap=free,--wrap=calloc,--wrap=realloc,--wrap=reallocarray,--wrap=getopt,--wrap=exit,--wrap=close,--wrap=sigaction,\
 --wrap=sem_init,--wrap=sem_open,--wrap=sem_post,--wrap=sem_wait,--wrap=sem_trywait,--wrap=sem_timedwait,--wrap=sem_getvalue,--wrap=sem_close,--wrap=sem_unlink,--wrap=sem_destroy,\
---wrap=shm_open,--wrap=shm_unlink,--wrap=mmap,--wrap=munmap
+--wrap=shm_open,--wrap=shm_unlink,--wrap=mmap,--wrap=munmap,\
+--wrap=ftruncate
 
 clean:
 	rm -rf main main_wrapped bin/* *.so *.ko *.o
diff --git a/proj/test1/src/intercept.c b/proj/test1/src/intercept.c
index a5130fe..c2a198f 100644
--- a/proj/test1/src/intercept.c
+++ b/proj/test1/src/intercept.c
@@ -45,6 +45,7 @@ static int (*__real_shm_open)(const char *, int, mode_t);
 static int (*__real_shm_unlink)(const char *);
 static void *(*__real_mmap)(void *, size_t, int, int, int, off_t);
 static int (*__real_munmap)(void *, size_t);
+extern int (*__real_ftruncate)(int, off_t);
 #define load(name) \
     if (((__real_ ## name) = dlsym(RTLD_NEXT, #name)) == NULL) { \
         fprintf(stderr, "intercept: unable to load symbol '%s': %s", #name, strerror(errno)); \
@@ -75,6 +76,7 @@ extern int __real_shm_open(const char *, int, mode_t);
 extern int __real_shm_unlink(const char *);
 extern void *__real_mmap(void *, size_t, int, int, int, off_t);
 extern int __real_munmap(void *, size_t);
+extern int __real_ftruncate(int, off_t);
 #define sym(name) __wrap_ ## name
 #endif
 
@@ -210,6 +212,19 @@ extern int __real_munmap(void *, size_t);
     msg("return %i; errno %s", -1, strerrorname_np(errno)); \
     return -1; }
 
+#define if_error_5_int_errno(name, err1, err2, err3, err4, err5) if (strncmp(buf, "fail ", 5) == 0) { \
+    if (strcmp(buf + 5, #err1) == 0) { errno = err1; \
+    } else if (strcmp(buf + 5, #err2) == 0) { errno = err2; \
+    } else if (strcmp(buf + 5, #err3) == 0) { errno = err3; \
+    } else if (strcmp(buf + 5, #err4) == 0) { errno = err4; \
+    } else if (strcmp(buf + 5, #err5) == 0) { errno = err5; \
+    } else { \
+        errno = 0; \
+        fprintf(stderr, "intercept: %s: invalid error code in fail command: '%s'\n", #name, buf + 5); \
+    } \
+    msg("return %i; errno %s", -1, strerrorname_np(errno)); \
+    return -1; }
+
 #define if_error_7_int_errno(name, err1, err2, err3, err4, err5, err6, err7) if (strncmp(buf, "fail ", 5) == 0) { \
     if (strcmp(buf + 5, #err1) == 0) { errno = err1; \
     } else if (strcmp(buf + 5, #err2) == 0) { errno = err2; \
@@ -504,6 +519,7 @@ static void init(void) {
     load(shm_unlink);
     load(mmap);
     load(munmap);
+    load(ftruncate);
 #endif
     atexit(fin);
     const char *val = getenv("INTERCEPT");
@@ -1206,3 +1222,19 @@ int sym(munmap)(void *addr, size_t len) {
     msg("return %i; errno %s", ret, strerrorname_np(errno));
     return ret;
 }
+
+int sym(ftruncate)(int fildes, off_t length) {
+    init();
+    msg("ftruncate(%i, %i): %p", fildes, length);
+    if (mode >= 4) {
+        char buf[BUFFER_SIZE];
+        rcv(buf, sizeof(buf));
+        if_modify_int_int(ftruncate, int, fildes, off_t, length)
+        else if_return_int_errno(ftruncate)
+        else if_error_5_int_errno(ftruncate, EINTR, EINVAL, EFBIG, EIO, EBADF)
+        else if_invalid(ftruncate)
+    }
+    const int ret = __real_ftruncate(fildes, length);
+    msg("return %i; errno %s", ret, strerrorname_np(errno));
+    return ret;
+}