Modules: db_redis for usrloc module

[SurendraPlivo]

This module provides db api interface to redis database

Pre-Submission Checklist

• Commit message has the format required by CONTRIBUTING guide
• Commits are split per component (core, individual modules, libs, utils, ...)
• Each component has a single commit (if not, squash them into one commit)
• No commits to README files for modules (changes must be done to docbook files
  in doc/ subfolder, the README file is autogenerated)

Type Of Change

• Small bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds new functionality)
• Breaking change (fix or feature that would change existing functionality)

Checklist:

• PR should be backported to stable branches
• Tested changes locally
• Related to issue #XXXX (replace XXXX with an open issue number)

Description

[SurendraPlivo]

@agranig @miconda

[Vadiml1024]

I would suggest some rework:

This code contains potential reentrancy problems because
of strtok usage... should be using strtok_r

In lot of places it uses sprintf, strcat, and strcpy which are subject to potential buffer overflows

in some places i see snprintf where source string size is passed as 2 parameter (buffer size). The idea is to pass target buffer size as second parameter

[SurendraPlivo]

@Vadiml1024 first of all thank you for review .

will you please help me out for reentrancy by producing it ? because we tested it for more than 300 rps and with 70000 endpoint. we didn't face this issue.anyway its good if you can point me to specific case.

in some places i see snprintf where source string size is passed as 2 parameter (buffer size). The idea is to pass target buffer size as second parameter ???? will you please point out these places.

[miconda]

The module is very tight to usrloc module, embedding even the default column names for location table. If this is going to be merge in this state, I would suggest to name it like db_redisuloc or something else that suggests the constraints with its usage. Later can be renamed.

Regarding the issue with snprintf size parameter reported above, I spotted like:

return_code = snprintf(table_name,(CON_TABLE(_h)->len+1) * sizeof(char),"%s%.*s%s",CON_TQUOTESZ(_h), CON_TABLE(_h)->len, CON_TABLE(_h)->s, CON_TQUOTESZ(_h));

Another aspect that needs to be take care is to check if pkg_malloc() returns NULL or not -- if there is no sufficient memory, it will cause a crash.