RFR: 8286212: Cgroup v1 initialization causes NPE on some systems [v2]

[Severin Gehwolf]

On Thu, 12 May 2022 15:58:57 GMT, Severin Gehwolf <sgehwolf at openjdk.org> wrote:

>> src/hotspot/os/linux/cgroupV1Subsystem_linux.cpp line 113:
>> 
>>> 111:           }
>>> 112:           buf[MAXPATHLEN-1] = '\0';
>>> 113:           _path = os::strdup(buf);
>> 
>> I think this code can be simplified a lot with stringStream and without strtok, so no need for fixed buffers (which may fail with longer path names) and no need for writable string copies on the stack.
>> 
>> Something like this:
>> 
>> stringStream ss;
>> ss.print_raw(_mount_point);
>> const char* p1 = _root;
>> const char* p2 = cgroup_path;
>> int last_matching_dash_pos = -1;
>> for (int i = 0; *p1 == *p2 && *p1 != 0; i ++) {
>> 	if (*p1 == '/') {
>> 		last_matching_dash_pos = i;
>> 	}
>>         p1++; p2++;
>> }
>> ss.print_raw(_root, last_matching_dash_pos);
>> // Now use ss.base() to access the assembled string
>
> Nice, thanks! I'll update it.

Done.

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PR: https://git.openjdk.java.net/jdk/pull/8629