[agw][mme] Replace ctime_r with strftime

[ssanadhya]

Signed-off-by: Shruti Sanadhya ssanadhya@fb.com

Summary

Replace ctime_r with recommended strftime

Test Plan

make integ_test for functional testing

tail /var/log/mme.log to make sure the time is printed correctly

vagrant@magma-dev:~/magma/lte/gateway$ tail /var/log/mme.log
000275 Mon Jan 04 23:37:17 2021 7FBF36BEDC80 INFO  SPGW-A tasks/sgw/pgw_config.c          :0588        SGi MTU (read)........: 1500
000276 Mon Jan 04 23:37:17 2021 7FBF36BEDC80 INFO  SPGW-A tasks/sgw/pgw_config.c          :0591        NAT ..................: true
000277 Mon Jan 04 23:37:17 2021 7FBF36BEDC80 INFO  SPGW-A tasks/sgw/pgw_config.c          :0594        User TCP MSS clamping : true
000278 Mon Jan 04 23:37:17 2021 7FBF36BEDC80 INFO  SPGW-A tasks/sgw/pgw_config.c          :0597        User IP masquerading  : false
000279 Mon Jan 04 23:37:17 2021 7FBF36BEDC80 INFO  SPGW-A tasks/sgw/pgw_config.c          :0600    - PCEF support ...........: false (in development)
000280 Mon Jan 04 23:37:17 2021 7FBF36BEDC80 INFO  SPGW-A tasks/sgw/pgw_config.c          :0646    - DNS Configuration:
000281 Mon Jan 04 23:37:17 2021 7FBF36BEDC80 INFO  SPGW-A tasks/sgw/pgw_config.c          :0649        IPv4 Primary Address ..........: 8.8.8.8
000282 Mon Jan 04 23:37:17 2021 7FBF36BEDC80 INFO  SPGW-A tasks/sgw/pgw_config.c          :0652        IPv4 Secondary Address ..........: 8.8.4.4
000283 Mon Jan 04 23:37:17 2021 7FBF36BEDC80 INFO  SPGW-A tasks/sgw/pgw_config.c          :0653    - Helpers:
000284 Mon Jan 04 23:37:17 2021 7FBF36BEDC80 INFO  SPGW-A tasks/sgw/pgw_config.c          :0656        Push PCO (DNS+MTU) ........: false

[ulaskozat]

LGTM

[pshelar]

This array can be allocated on stack of caller to avoid dynamic memory allocation. Caller can pass explicit array pointer. is there any downside of this ?

[ssanadhya]

Yes @pshelar, that is also a feasible approach. We will have to pass the array pointer as well as the array length to the function, increasing the number of arguments to the function. Alternatively, we can fix the size of the time_str using a macro and just use that everywhere. What do you think?

[ssanadhya]

Modified in 744d161