Add trace module, used for logging all function calls

Remove previous implementation from e2lib and move it into a
free-standing module. Extend so it can be disabled and enabled when
convenient.

Signed-off-by: Tobias Ulmer <tu@emlix.com>

diff --git a/generic/Makefile b/generic/Makefile
index 37d8ea57f2e4b406e066c04af4e0402586b345fd..ebde45a4345aad73722869980b6308aa2813a55c 100644 (file)
--- a/generic/Makefile
+++ b/generic/Makefile
@@ -31,7 +31,7 @@ include $(TOPLEVEL)/make.vars
 
 LUA_LIBS = strict.lua plugin.lua e2lib.lua
 LUA_LIBS += e2option.lua hash.lua tools.lua transport.lua cache.lua url.lua
-LUA_LIBS += generic_git.lua eio.lua err.lua lock.lua errno.lua
+LUA_LIBS += generic_git.lua eio.lua err.lua lock.lua errno.lua trace.lua
 SO_LIBS = sha1.so leio.so le2lib.so
 
 CLEAN_FILES = *~ *.o *.so

diff --git a/generic/e2lib.lua b/generic/e2lib.lua
index a6d27853b3075c8c44cd9a9ab9d2247eda6a57cf..41f17614aeba37e6b2ebe370ffdc7bc3cbcb0977 100644 (file)
--- a/generic/e2lib.lua
+++ b/generic/e2lib.lua
@@ -56,6 +56,7 @@ local tools = require("tools")
 local cache = require("cache")
 local eio = require("eio")
 local le2lib = require("le2lib")
+local trace = require("trace")
 
 -- Module-level global variables
 --
@@ -318,9 +319,8 @@ end
 -- @return Error object on failure.
 function e2lib.init()
     e2lib.log(4, "e2lib.init()")
-    -- DEBUG: change to "cr" to log return from function
-    local traceflags = os.getenv("E2_TRACE") or "c"
-    debug.sethook(e2lib.tracer, traceflags)
+
+    trace.enable()
 
     local rc, re = e2lib.signal_reset()
     if not rc then
@@ -439,74 +439,6 @@ function e2lib.init2()
     return true
 end
 
---- function call tracer
--- @param event string: type of event
--- @param line line number of event (unused)
-function e2lib.tracer(event, line)
-    local ftbl = debug.getinfo(2)
-    if ftbl == nil or ftbl.name == nil then
-        return
-    end
-
-    -- approximate module name, not always accurate but good enough
-    local module
-    if ftbl.source == nil or ftbl.source == "=[C]" then
-        module = "C."
-        -- DEBUG: comment this to see all C calls.
-        return
-    else
-        module = string.match(ftbl.source, "(%w+%.)lua$")
-        if module == nil then
-            module = "<unknown module>."
-            -- DEBUG: comment this to see all unknown calls.
-            return
-        end
-    end
-
-    if event == "call" then
-        local out = string.format("%s%s(", module, ftbl.name)
-        for lo = 1, 10 do
-            local name, value = debug.getlocal(2, lo)
-            if name == nil or name == "(*temporary)" then
-                break
-            end
-            if lo > 1 then
-                out = out .. ", "
-            end
-
-            if type(value) == "string" then
-                local isbinary = false
-
-                -- check the first 40 bytes for values common in binary data
-                for _,v in ipairs({string.byte(value, 1, 41)}) do
-                    if (v >= 0 and v < 9) or (v > 13 and v < 32) then
-                        isbinary = true
-                        break
-                    end
-                end
-
-                if isbinary then
-                    out = string.format("%s%s=<binary data>", out, name)
-                else
-                    local svalue = string.sub(value, 0, 800)
-                    if string.len(value) > string.len(svalue) then
-                        svalue = svalue .. "..."
-                    end
-
-                    out = string.format("%s%s=\"%s\"", out, name, svalue)
-                end
-            else
-                out = string.format("%s%s=%s", out, name, tostring(value))
-            end
-
-        end
-        out = out .. ")"
-        e2lib.log(4, out)
-    else
-        e2lib.logf(4, "< %s%s", module, ftbl.name)
-    end
-end
-
 --- Print a warning, composed by concatenating all arguments to a string.
 -- @param ... any number of strings
 -- @return nil

diff --git a/generic/trace.lua b/generic/trace.lua
new file mode 100644 (file)
index 0000000..2c9cecf
--- /dev/null
+++ b/generic/trace.lua
@@ -0,0 +1,108 @@
+--- Function call tracing
+-- @module generic.trace
+
+-- Copyright (C) 2013 emlix GmbH, see file AUTHORS
+--
+-- This file is part of e2factory, the emlix embedded build system.
+-- For more information see http://www.e2factory.org
+--
+-- e2factory is a registered trademark of emlix GmbH.
+--
+-- e2factory is free software: you can redistribute it and/or modify it under
+-- the terms of the GNU General Public License as published by the
+-- Free Software Foundation, either version 3 of the License, or (at your
+-- option) any later version.
+--
+-- This program is distributed in the hope that it will be useful, but WITHOUT
+-- ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+-- FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+-- more details.
+
+local trace = {}
+local e2lib = require("e2lib")
+local strict = require("strict")
+
+--- Function call tracer. Logs all function calls at debug level while active.
+-- @param event string: type of event
+-- @param line line number of event (unused)
+local function tracer(event, line)
+    local ftbl, module, out, name, value, isbinary, svalue
+
+    ftbl = debug.getinfo(2)
+    if ftbl == nil or ftbl.name == nil then
+        return
+    end
+
+    -- approximate module name, not always accurate but good enough
+    if ftbl.source == nil or ftbl.source == "=[C]" then
+        module = "C."
+        -- DEBUG: comment this to see all C calls.
+        return
+    else
+        module = string.match(ftbl.source, "(%w+%.)lua$")
+        if module == nil then
+            module = "<unknown module>."
+            -- DEBUG: comment this to see all unknown calls.
+            return
+        end
+    end
+
+    if event == "call" then
+        out = string.format("%s%s(", module, ftbl.name)
+        for lo = 1, 10 do
+            name, value = debug.getlocal(2, lo)
+            if name == nil or name == "(*temporary)" then
+                break
+            end
+            if lo > 1 then
+                out = out .. ", "
+            end
+
+            if type(value) == "string" then
+                isbinary = false
+
+                -- check the first 40 bytes for values common in binary data
+                for _,v in ipairs({string.byte(value, 1, 41)}) do
+                    if (v >= 0 and v < 9) or (v > 13 and v < 32) then
+                        isbinary = true
+                        break
+                    end
+                end
+
+                if isbinary then
+                    out = string.format("%s%s=<binary data>", out, name)
+                else
+                    svalue = string.sub(value, 0, 800)
+                    if string.len(value) > string.len(svalue) then
+                        svalue = svalue .. "..."
+                    end
+
+                    out = string.format("%s%s=\"%s\"", out, name, svalue)
+                end
+            else
+                out = string.format("%s%s=%s", out, name, tostring(value))
+            end
+
+        end
+        out = out .. ")"
+        e2lib.log(4, out)
+    else
+        e2lib.logf(4, "< %s%s", module, ftbl.name)
+    end
+end
+
+--- Enable function call tracer.
+function trace.enable()
+    e2lib.log(4, "trace.enable()")
+    local flags = os.getenv("E2_TRACE") or "c"
+    debug.sethook(tracer, flags)
+end
+
+--- Disable function call tracer.
+function trace.disable()
+    debug.sethook()
+end
+
+return strict.lock(trace)
+
+-- vim:sw=4:sts=4:et: