tests: add read_int_from_file function to libtests

* tests/overflowuid.c (read_int_from_file): New function.
(check_overflow_id): Use it.
* tests/tests.h (read_int_from_file): New prototype.

diff --git a/tests/overflowuid.c b/tests/overflowuid.c
index d9d9e3719b22fc83ba9f9b7e6bbc48a700fb274f..a3c742b46016999dc566079deaa79a93e54d8697 100644 (file)
--- a/tests/overflowuid.c
+++ b/tests/overflowuid.c
@@ -31,27 +31,55 @@
 #include <stdlib.h>
 #include <unistd.h>
 
+int
+read_int_from_file(const char *const fname, int *const pvalue)
+{
+       const int fd = open(fname, O_RDONLY);
+       if (fd < 0)
+               return -1;
+
+       long lval;
+       char buf[sizeof(lval) * 3];
+       int n = read(fd, buf, sizeof(buf) - 1);
+       int saved_errno = errno;
+       close(fd);
+
+       if (n < 0) {
+               errno = saved_errno;
+               return -1;
+       }
+
+       buf[n] = '\0';
+       char *endptr = 0;
+       errno = 0;
+       lval = strtol(buf, &endptr, 10);
+       if (!endptr || (*endptr && '\n' != *endptr)
+#if INT_MAX < LONG_MAX
+           || lval > INT_MAX || lval < INT_MIN
+#endif
+           || ERANGE == errno) {
+               if (!errno)
+                       errno = EINVAL;
+               return -1;
+       }
+
+       *pvalue = (int) lval;
+       return 0;
+}
+
 static void
 check_overflow_id(const int id, const char *overflowid)
 {
-       int fd = open(overflowid, O_RDONLY);
-       if (fd < 0) {
+       int n;
+
+       if (read_int_from_file(overflowid, &n)) {
                if (ENOENT == errno)
                        return;
-               perror_msg_and_fail("open: %s", overflowid);
+               perror_msg_and_fail("read_int_from_file: %s", overflowid);
        }
 
-       /* we trust the kernel */
-       char buf[sizeof(int)*3];
-       int n = read(fd, buf, sizeof(buf) - 1);
-       if (n > 0) {
-               buf[n] = '\0';
-               n = atoi(buf);
-               if (id == n)
-                       error_msg_and_skip("%d matches %s", id, overflowid);
-       }
-
-       close(fd);
+       if (id == n)
+               error_msg_and_skip("%d matches %s", id, overflowid);
 }
 
 void

diff --git a/tests/tests.h b/tests/tests.h
index 02d588edf5d1ebdbe6f83080071dd8f827a021a3..e2928f0968ea18afea483935c9771bc7586b89d1 100644 (file)
--- a/tests/tests.h
+++ b/tests/tests.h
@@ -84,6 +84,9 @@ void print_quoted_string(const char *);
 /* Print memory in a quoted form. */
 void print_quoted_memory(const char *, size_t);
 
+/* Read an int from the file. */
+int read_int_from_file(const char *, int *);
+
 /* Check whether given uid matches kernel overflowuid. */
 void check_overflowuid(const int);