trace: fix build with gcc 10

Prevent from writing beyond the allocated memory.

GCC 10 compiling output:
eal_common_trace_utils.c: In function 'eal_trace_dir_args_save':
eal_common_trace_utils.c:290:24: error: '__builtin___sprintf_chk'   \
	may write a terminating nul past the end of the destination \
	[-Werror=format-overflow=]
  290 |  sprintf(dir_path, "%s/", optarg);
      |                        ^

Fixes: 8af866df8d8c ("trace: add trace directory configuration parameter")

Signed-off-by: Phil Yang <phil.yang@arm.com>
Reviewed-by: Lijian Zhang <lijian.zhang@arm.com>
Tested-by: Lijian Zhang <lijian.zhang@arm.com>
Acked-by: Sunil Kumar Kori <skori@marvell.com>
Signed-off-by: David Marchand <david.marchand@redhat.com>

diff --git a/lib/librte_eal/common/eal_common_trace_utils.c b/lib/librte_eal/common/eal_common_trace_utils.c
index eed861e..64f58fb 100644 (file)
--- a/lib/librte_eal/common/eal_common_trace_utils.c
+++ b/lib/librte_eal/common/eal_common_trace_utils.c
@@ -245,22 +245,19 @@ int
 eal_trace_dir_args_save(char const *val)
 {
        struct trace *trace = trace_obj_get();
-       uint32_t size = sizeof(trace->dir);
-       char *dir_path = NULL;
+       char *dir_path;
        int rc;
 
-       if (strlen(val) >= size) {
+       if (strlen(val) >= sizeof(trace->dir) - 1) {
                trace_err("input string is too big");
                return -ENAMETOOLONG;
        }
 
-       dir_path = (char *)calloc(1, size);
-       if (dir_path == NULL) {
-               trace_err("fail to allocate memory");
+       if (asprintf(&dir_path, "%s/", val) == -1) {
+               trace_err("failed to copy directory: %s", strerror(errno));
                return -ENOMEM;
        }
 
-       sprintf(dir_path, "%s/", val);
        rc = trace_dir_update(dir_path);
 
        free(dir_path);