collect enter and exit times of the syscall tracepoints

1 files changed, 26 insertions, 4 deletions

diff --git a/ioriotng.bpf.c b/ioriotng.bpf.c
index d9b0f5a..8f39573 100644
--- a/ioriotng.bpf.c
+++ b/ioriotng.bpf.c
@@ -5,8 +5,6 @@
 #include <bpf/bpf_helpers.h>
 #include "maps.bpf.h"
 
-// TODO: Split out this file into several *.bpf.c programs.
-
 // TODO: Make UID_FILTER configurable via a flag from the userland part.
 // For now, this is set to my own user for development purposes.
 #define UID_FILTER 1001 
@@ -19,6 +17,7 @@ int handle_enter_open(struct trace_event_raw_sys_enter *ctx) {
     u32 tid = bpf_get_current_pid_tgid();
     struct open_event event = {
         .op_id = OPEN,
+        .enter_time = bpf_ktime_get_ns(),
     };
 
     bpf_probe_read_user_str(event.filename, sizeof(event.filename), (void *)ctx->args[0]);
@@ -40,6 +39,7 @@ int handle_exit_open(struct trace_event_raw_sys_exit *ctx) {
         return 0;
     }
     eventp->fd = ctx->ret;
+    eventp->exit_time = bpf_ktime_get_ns();
     bpf_perf_event_output(ctx, &open_event_map, BPF_F_CURRENT_CPU, eventp, sizeof(struct open_event));
     bpf_map_delete_elem(&open_event_temp_map, &tid);
 
@@ -52,7 +52,10 @@ int handle_enter_openat(struct trace_event_raw_sys_enter *ctx) {
         return 0;
 
     u32 tid = bpf_get_current_pid_tgid();
-    struct open_event event = { .op_id = OPEN_AT };
+    struct open_event event = {
+        .op_id = OPEN_AT,
+        .enter_time = bpf_ktime_get_ns(),
+    };
 
     bpf_probe_read_user_str(event.filename, sizeof(event.filename), (void *)ctx->args[1]);
     bpf_get_current_comm(&event.comm, sizeof(event.comm));
@@ -75,12 +78,31 @@ int handle_enter_close(struct trace_event_raw_sys_enter *ctx) {
     if ((bpf_get_current_uid_gid() & 0xFFFFFFFF) != UID_FILTER)
         return 0;
 
+    u32 tid = bpf_get_current_pid_tgid();
     struct fd_event event = {
         .fd = (int)ctx->args[0],
         .op_id = CLOSE,
         .tid = bpf_get_current_pid_tgid(),
+        .enter_time = bpf_ktime_get_ns(),
     };
-    bpf_perf_event_output(ctx, &fd_event_map, BPF_F_CURRENT_CPU, &event, sizeof(struct fd_event));
+    bpf_map_update_elem(&fd_event_temp_map, &tid, &event, BPF_ANY);
+
+    return 0;
+}
+
+SEC("tracepoint/syscalls/sys_exit_close")
+int handle_exit_close(struct trace_event_raw_sys_enter *ctx) {
+    if ((bpf_get_current_uid_gid() & 0xFFFFFFFF) != UID_FILTER)
+        return 0;
+
+    u32 tid = bpf_get_current_pid_tgid();
+    struct open_event *eventp = bpf_map_lookup_elem(&fd_event_temp_map, &tid);
+    if (!eventp) {
+        return 0;
+    }
+    eventp->exit_time = bpf_ktime_get_ns();
+    bpf_perf_event_output(ctx, &fd_event_map, BPF_F_CURRENT_CPU, eventp, sizeof(struct fd_event));
+    bpf_map_delete_elem(&fd_event_temp_map, &tid);
 
     return 0;
 }