Add kallsyms querying

Author: jpsamaroo

src/BPFnative.jl

@@ -82,6 +82,7 @@ import ..API
 include("host/syscall.jl")
 include("host/maps.jl")
 include("host/socket.jl")
+include("host/kallsyms.jl")
 end
 
 # Compiler

src/host/kallsyms.jl

@@ -0,0 +1,32 @@
+function find_ksym(addr::UInt64)
+    start, stop = UInt64(0), addr
+    rgx = r"([0-9abcdef]*) ([a-zA-Z]) ([0-9a-zA-Z_\-]*)"
+    last_addr = start
+    last_kind = "?"
+    last_name = ""
+    for line in readlines(open("/proc/kallsyms", "r"))
+        m = match(rgx, line)
+        @assert m !== nothing
+        start_addr, kind, name = m.captures
+        start_addr = parse(UInt64, "0x"*start_addr)
+        if start_addr > stop
+            return last_addr, last_kind, last_name
+        elseif start_addr == stop
+            return addr, kind, name
+        end
+        last_addr = addr
+        last_kind = kind
+        last_name = name
+    end
+end
+function stack_to_string(nt::NTuple{N,UInt64}) where N
+    iob = IOBuffer()
+    for i in 1:N
+        addr = nt[i]
+        if addr == UInt64(0)
+            break
+        end
+        println(iob, "$(find_ksym(addr)[3])")
+    end
+    String(take!(iob))
+end