From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thomas Monjalon Subject: Re: [PATCH] eal: fix strdup usages in internal config Date: Thu, 31 Jan 2019 16:04:23 +0100 Message-ID: <1614490.ZEn2XMpOzn@xps> References: <4e041e83fb00d8d818682997f795928c36b3283a.1547127516.git.anatoly.burakov@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7Bit Cc: "Burakov, Anatoly" , dev@dpdk.org, Bruce Richardson , ferruh.yigit@intel.com, andy01011501@163.com, Yongseok Koh , "stable@dpdk.org" To: Kevin Traynor Return-path: In-Reply-To: List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" 31/01/2019 15:15, Kevin Traynor: > On 01/31/2019 02:10 PM, Burakov, Anatoly wrote: > > On 31-Jan-19 11:21 AM, Kevin Traynor wrote: > >> On 01/10/2019 01:38 PM, Anatoly Burakov wrote: > >>> Currently, we use strdup in a few places to store command-line > >>> parameter values for certain internal config values. There are > >>> several issues with that. > >>> > >>> First of all, they're never freed, so memory ends up leaking > >>> either after EAL exit, or when these command-line options are > >>> supplied multiple times. > >>> > >>> Second of all, they're defined as `const char *`, so they > >>> *cannot* be freed even if we wanted to. > >>> > >>> Finally, strdup may return NULL, which will be stored in the > >>> config. For most fields, NULL is a valid value, but for the > >>> default prefix, the value is always expected to be valid. > >>> > >>> To fix all of this, three things are done. First, we change > >>> the definitions of these values to `char *` as opposed to > >>> `const char *`. This does not break the ABI, and previous > >>> code assumes constness (which is more restrictive), so it's > >>> safe to do so. > >>> > >>> Then, fix all usages of strdup to check return value, and add > >>> a cleanup function that will free the memory occupied by > >>> these strings, as well as freeing them before assigning a new > >>> value to prevent leaks when parameter is specified multiple > >>> times. > >>> > >>> And finally, add an internal API to query hugefile prefix, so > >>> that, absent of a valid value, a default value will be > >>> returned, and also fix up all usages of hugefile prefix to > >>> use this API instead of accessing hugefile prefix directly. > >>> > >>> Bugzilla ID: 108 > >>> > >> > >> Hi Anatoly - this doesn't have stable or Fixes tags, but the bugzilla > >> was reported on 17.11. Is it for backport to stable branches? > >> > > > > It can be. Whether it's worth the effort of backporting is not my call :) > > > > It's fine for 18.11 branch anyway, just needed a little help due to some > changed context. I will send diff to stable list as normal. Nothing was broken. I see it like an improvement. Not sure it is worth the effort.