evil: Implement ftruncate

Create POSIX-compliant ftruncate with tests.

src/lib/evil/evil_unistd.c

@@ -25,6 +25,26 @@ execvp(const char *file, char *const argv[])
 LONGLONG _evil_time_freq;
 LONGLONG _evil_time_count;
 
+EVIL_API int
+ftruncate(int fd, off_t size)
+{
+   HANDLE file = (HANDLE)_get_osfhandle(fd);
+
+   if (SetFilePointer(file, (LONG)size, NULL, FILE_BEGIN) == INVALID_SET_FILE_POINTER)
+     {
+       _set_errno(EINVAL);
+       return -1;
+     }
+
+   if (!SetEndOfFile(file))
+     {
+       _set_errno(EIO);
+       return -1;
+     }
+
+    return 0;
+}
+
 /*
  * Time related functions
  *

src/lib/evil/evil_unistd.h

@@ -23,6 +23,7 @@
 #include <process.h> // for _execvp (but not execvp), getpid
 #undef execvp 
 EVIL_API int execvp(const char *file, char *const argv[]);
+EVIL_API int ftruncate(int fd, off_t size);
 
 /* Values for the second argument to access.  These may be OR'd together.  */
 #define R_OK    4       /* Test for read permission.  */

src/tests/evil/evil_test_unistd.c

@@ -22,6 +22,8 @@
 
 #include <stdlib.h>
 #include <stdio.h>
+#include <io.h>
+#include <fcntl.h>
 
 # define WIN32_LEAN_AND_MEAN
 # include <winsock2.h>
@@ -109,7 +111,38 @@ EFL_START_TEST(evil_unistd_pipe)
 }
 EFL_END_TEST
 
+EFL_START_TEST(evil_unistd_ftruncate)
+{
+   FILE* f = fopen("foo.txt", "wb");
+   ck_assert(f);
+   fseek(f, 0L, SEEK_END);
+   ck_assert_int_eq(ftell(f), 0);
+
+   int fd = fileno(f);
+   int ret;
+
+   ret = ftruncate(fd, 16L);
+   ck_assert(ret >= 0);
+   fseek(f, 0L, SEEK_END);
+   ck_assert_int_eq(ftell(f), 16);
+
+   ret = ftruncate(fd, 8L);
+   ck_assert(ret >= 0);
+   fseek(f, 0L, SEEK_END);
+   ck_assert_int_eq(ftell(f), 8);
+
+   ret = ftruncate(fd, -8L);
+   ck_assert(ret < 0);
+   ck_assert_int_eq(errno, EINVAL);
+   fseek(f, 0L, SEEK_END);
+   ck_assert_int_eq(ftell(f), 8);
+
+   fclose(f);
+}
+EFL_END_TEST
+
 void evil_test_unistd(TCase *tc)
 {
    tcase_add_test(tc, evil_unistd_pipe);
+   tcase_add_test(tc, evil_unistd_ftruncate);
 }