Fix elf/sotruss-lib format-truncation error.

Building 64-bit glibc with GCC mainline fails with:

../elf/sotruss-lib.c: In function 'la_version':
../elf/sotruss-lib.c:91:28: error: '%lu' directive output may be truncated writing between 1 and 20 bytes into a region of size 11 [-Werror=format-truncation=]
      snprintf (endp, 12, ".%lu", (unsigned long int) pid);
                            ^~~
../elf/sotruss-lib.c:91:26: note: using the range [1, 18446744073709551615] for directive argument
      snprintf (endp, 12, ".%lu", (unsigned long int) pid);
                          ^~~~~~
../elf/sotruss-lib.c:91:6: note: format output between 3 and 22 bytes into a destination of size 12
      snprintf (endp, 12, ".%lu", (unsigned long int) pid);
      ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Pids from getpid cannot actually be negative, but the compiler doesn't
know this.  Other places in this file use (signed) long int for
printing, so this patch makes this place do so as well.  Then it
increases the buffer size by one byte to allow for the minus sign that
can't actually occur.  It doesn't seem worth using diagnostic pragmas
to save one byte; other place in this file just use a cruder 3 *
sizeof (pid_t) calculation for number of digits.

Tested with GCC mainline with compilation for aarch64 with
build-many-glibcs.py, and with glibc testsuite for x86_64 (built with
GCC 6).

	* elf/sotruss-lib.c (init): Increase space allocated for pid by
	one byte.  Print it with %ld, cast to long int.

diff --git a/ChangeLog b/ChangeLog
index 4f87985cdbaa8749b3512a7481118e14fe513f3f..fe612a80b9c06f4fe501b282c75fd9288de7b434 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2017-01-11  Joseph Myers  <joseph@codesourcery.com>
+
+       * elf/sotruss-lib.c (init): Increase space allocated for pid by
+       one byte.  Print it with %ld, cast to long int.
+
 2017-01-11  Szabolcs Nagy  <szabolcs.nagy@arm.com>
 
        * scripts/build-many-glibcs.py (os.cpu_count): Add compatibility definition.

diff --git a/elf/sotruss-lib.c b/elf/sotruss-lib.c
index a27ab9f6d17bc963aee75fdc3194d29dd23bf969..da2fedd52af691f8886fff48956aee4a5d2c995c 100644 (file)
--- a/elf/sotruss-lib.c
+++ b/elf/sotruss-lib.c
@@ -84,11 +84,11 @@ init (void)
 
       if (out_filename != NULL && out_filename[0] != 0)
        {
-         size_t out_filename_len = strlen (out_filename) + 12;
+         size_t out_filename_len = strlen (out_filename) + 13;
          char fullname[out_filename_len];
          char *endp = stpcpy (fullname, out_filename);
          if (which_process == NULL || which_process[0] == '\0')
-           snprintf (endp, 12, ".%lu", (unsigned long int) pid);
+           snprintf (endp, 13, ".%ld", (long int) pid);
 
          out_fd = open (fullname, O_RDWR | O_CREAT | O_TRUNC, 0666);
          if (out_fd != -1)