From 38d01bd6df937f69c881df61b111492e941f2b74 Mon Sep 17 00:00:00 2001 From: Joseph Myers Date: Wed, 11 Jan 2017 13:57:59 +0000 Subject: 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. --- elf/sotruss-lib.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'elf/sotruss-lib.c') diff --git a/elf/sotruss-lib.c b/elf/sotruss-lib.c index a27ab9f6d1..da2fedd52a 100644 --- 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) -- cgit v1.2.3