[jira] [Commented] (MAPREDUCE-6005) native-task: fix some valgrind errors

[Sean Zhong (JIRA)]

    [ 
https://issues.apache.org/jira/browse/MAPREDUCE-6005?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14080567#comment-14080567
 ] 

Sean Zhong commented on MAPREDUCE-6005:
---------------------------------------

One more:

Can you also fix 
{quote}
string StringUtil::ToString(int32_t v) {
  char tmp[32];
  snprintf(tmp, 32, "%d", v);
  return tmp;
}

string StringUtil::ToString(uint32_t v) {
  char tmp[32];
  snprintf(tmp, 32, "%u", v);
  return tmp;
}

string StringUtil::ToString(int64_t v) {
  char tmp[32];
  snprintf(tmp, 32, "%lld", (long long int)v);
  return tmp;
}

string StringUtil::ToString(int64_t v, char pad, int64_t len) {
  char tmp[32];
  snprintf(tmp, 32, "%%%c%lldlld", pad, len);
  return Format(tmp, v);
}

string StringUtil::ToString(uint64_t v) {
  char tmp[32];
  snprintf(tmp, 32, "%llu", (long long unsigned int)v);
  return tmp;
}

string StringUtil::ToString(bool v) {
  if (v) {
    return "true";
  } else {
    return "false";
  }
}

string StringUtil::ToString(float v) {
  char tmp[32];
  snprintf(tmp, 32, "%f", v);
  return tmp;
}

string StringUtil::ToString(double v) {
  char tmp[32];
  snprintf(tmp, 32, "%lf", v);
  return tmp;
}

{quote}

1) it is not safe to convert a char array to a string like this. It will 
trigger a copy contructor. But by 
http://www.cplusplus.com/reference/string/string/string/, 
{quote}
string (const char* s);
the string need to be null terminated.
{quote}

2)   snprintf(tmp, 32, "%lf", v) impl is platform dependant when size  “32” 
equals the v length. It may truncate the raw data, or may ignore the null 
terminitor. http://linux.die.net/man/3/snprintf, 
{quote}
The functions snprintf() and vsnprintf() write at most size bytes (including 
the terminating null byte ('\0')) to str.
{quote}

> native-task: fix some valgrind errors 
> --------------------------------------
>
>                 Key: MAPREDUCE-6005
>                 URL: https://issues.apache.org/jira/browse/MAPREDUCE-6005
>             Project: Hadoop Map/Reduce
>          Issue Type: Sub-task
>          Components: task
>            Reporter: Binglin Chang
>            Assignee: Binglin Chang
>         Attachments: MAPREDUCE-6005.v1.patch, MAPREDUCE-6005.v2.patch, 
> MAPREDUCE-6005.v3.patch
>
>
> Running test with valgrind shows there are some bugs, this jira try to fix 
> them.



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