On 12-Jul-19 3:22 AM, Yasufumi Ogawa wrote:
On 2019/07/11 22:14, Burakov, Anatoly wrote:
On 11-Jul-19 12:57 PM, Yasufumi Ogawa wrote:
On 2019/07/11 19:53, Burakov, Anatoly wrote:
On 11-Jul-19 11:31 AM, yasufu...@gmail.com wrote:
From: Yasufumi Ogawa <ogawa.yasuf...@lab.ntt.co.jp>
<...>
+ if (getpid() == 1) {
+ FILE *hn_fp;
+ hn_fp = fopen("/etc/hostname", "r");
+ if (hn_fp == NULL) {
+ RTE_LOG(ERR, EAL,
+ "Cannot open '/etc/hostname' for secondary\n");
+ return -1;
+ }
+
+ /* with docker, /etc/hostname just has one entry of
hostname */
+ if (fscanf(hn_fp, "%s", proc_id) == EOF) {
Apologies for not pointing this out earlier, but do i understand
correctly that there's no bounds checking here, and fscanf() will
write however many bytes it wants?
I understand "%s" is not appropriate. hostname is 12 bytes char and I
thought proc_id[16] is enough, but it is unsafe. In addition,
hostname can be defined by user with docker's option, so it should be
enough for user defined name.
How do you think expecting max 32 chars of hostname and set boundary
"%32s" as following?
proc_id[33]; /* define proc id from hostname less than 33
bytes. */
...
if (fscanf(hn_fp, "%32s", proc_id) == EOF) {
As long as it takes NULL-termination into account as well, it should
be OK. I can't recall off the top of my head if %32s includes NULL
terminator (probably not?).
Do you agree if initialize with NULL chars to ensure proc_id is
NULL-terminated? As tested on my environment, "%Ns" sets next of Nth
char as NULL, but it seems more reliable.
proc_id[33] = { 0 };
Yasufumi
Yes, that should be OK.
--
Thanks,
Anatoly
