[Nettrace] Handle const char * to avoid truncating metadata #191
Description
Events with const char * fields have their metadata truncated in the generated nettrace.
cat /sys/kernel/tracing/events/syscalls/
sys_enter_open/format
name: sys_enter_open
ID: 683
format:
field:unsigned short common_type; offset:0; size:2; signed:0;
field:unsigned char common_flags; offset:2; size:1; signed:0;
field:unsigned char common_preempt_count; offset:3; size:1; signed:0;
field:int common_pid; offset:4; size:4; signed:1;
field:int __syscall_nr; offset:8; size:4; signed:1;
field:const char * filename; offset:16; size:8; signed:0;
field:int flags; offset:24; size:8; signed:0;
field:umode_t mode; offset:32; size:8; signed:0;
cat /sys/kernel/tracing/events/syscalls/sys_enter_openat/format
name: sys_enter_openat
ID: 681
format:
field:unsigned short common_type; offset:0; size:2; signed:0;
field:unsigned char common_flags; offset:2; size:1; signed:0;
field:unsigned char common_preempt_count; offset:3; size:1; signed:0;
field:int common_pid; offset:4; size:4; signed:1;
field:int __syscall_nr; offset:8; size:4; signed:1;
field:int dfd; offset:16; size:8; signed:0;
field:const char * filename; offset:24; size:8; signed:0;
field:int flags; offset:32; size:8; signed:0;
field:umode_t mode; offset:40; size:8; signed:0;
Viewing the event in PerfView, the fields starting from const char * filename are all missing.
The filename probably cannot be resolved without eprobes, but it would still be useful to see trailing metadata that can be resolved.