profilers: print user-friendly errors

Prior to this patch, there was no error-checking in profilers,
which resulted in raw Lua errors being reported in cases of
non-existing paths or corrupt file structures. This patch adds
error handling, so all parsing errors are now reported in a
user-friendly manner.

Event parsing is now moved into a separate profiler-agnostic
module.

Tool CLI flag tests are adapted correspondingly to error message
changes.

Resolves tarantool/tarantool#9217
Part of tarantool/tarantool#5994

test/tarantool-tests/gh-5688-tool-cli-flag.test.lua

@@ -42,7 +42,7 @@ local SMOKE_CMD_SET = {
 local MEMPROF_CMD_SET = {
   {
     cmd = MEMPROF_PARSER .. BAD_PATH,
-    like = 'fopen, errno: 2',
+    like = 'Failed to open',
   },
   {
     cmd = MEMPROF_PARSER .. TMP_BINFILE_MEMPROF,
@@ -61,7 +61,7 @@ local MEMPROF_CMD_SET = {
 local SYSPROF_CMD_SET = {
   {
     cmd = SYSPROF_PARSER .. BAD_PATH,
-    like = 'fopen, errno: 2',
+    like = 'Failed to open',
   },
   {
     cmd = SYSPROF_PARSER .. TMP_BINFILE_SYSPROF,

tools/CMakeLists.txt

@@ -18,6 +18,7 @@ else()
     memprof.lua
     utils/avl.lua
     utils/bufread.lua
+    utils/profile_data_reader.lua
     utils/symtab.lua
   )
   list(APPEND LUAJIT_TOOLS_DEPS tools-parse-memprof)
@@ -36,6 +37,7 @@ else()
   install(FILES
       ${CMAKE_CURRENT_SOURCE_DIR}/utils/avl.lua
       ${CMAKE_CURRENT_SOURCE_DIR}/utils/bufread.lua
+      ${CMAKE_CURRENT_SOURCE_DIR}/utils/profile_data_reader.lua
       ${CMAKE_CURRENT_SOURCE_DIR}/utils/symtab.lua
     DESTINATION ${LUAJIT_DATAROOTDIR}/utils
     PERMISSIONS
@@ -67,6 +69,7 @@ else()
     sysprof/collapse.lua
     sysprof.lua
     utils/bufread.lua
+    utils/profile_data_reader.lua
     utils/symtab.lua
   )
   list(APPEND LUAJIT_TOOLS_DEPS tools-parse-sysprof)
@@ -85,6 +88,7 @@ else()
   )
   install(FILES
       ${CMAKE_CURRENT_SOURCE_DIR}/utils/bufread.lua
+      ${CMAKE_CURRENT_SOURCE_DIR}/utils/profile_data_reader.lua
       ${CMAKE_CURRENT_SOURCE_DIR}/utils/symtab.lua
     DESTINATION ${LUAJIT_DATAROOTDIR}/utils
     PERMISSIONS

tools/memprof.lua

@@ -10,11 +10,10 @@
 -- Major portions taken verbatim or adapted from the LuaVela.
 -- Copyright (C) 2015-2019 IPONWEB Ltd.
 
-local bufread = require "utils.bufread"
-local memprof = require "memprof.parse"
-local process = require "memprof.process"
-local symtab = require "utils.symtab"
-local view = require "memprof.humanize"
+local memprof = require('memprof.parse')
+local process = require('memprof.process')
+local reader = require('utils.profile_data_reader')
+local view = require('memprof.humanize')
 
 local stdout, stderr = io.stdout, io.stderr
 local match, gmatch = string.match, string.gmatch
@@ -107,9 +106,11 @@ local function parseargs(args)
 end
 
 local function dump(inputfile)
-  local reader = bufread.new(inputfile)
-  local symbols = symtab.parse(reader)
-  local events = memprof.parse(reader, symbols)
+  -- XXX: This function exits with a non-zero exit code and
+  -- prints an error message if it encounters any failure during
+  -- the process of parsing.
+  local events, symbols = reader(inputfile, memprof.parse)
+
   if not config.leak_only then
     view.profile_info(events, config)
   end

tools/sysprof.lua

@@ -1,6 +1,5 @@
-local bufread = require "utils.bufread"
-local sysprof = require "sysprof.parse"
-local symtab = require "utils.symtab"
+local reader = require('utils.profile_data_reader')
+local sysprof = require('sysprof.parse')
 
 local stdout, stderr = io.stdout, io.stderr
 local match, gmatch = string.match, string.gmatch
@@ -77,10 +76,12 @@ local function parseargs(args)
   return args[args.argn]
 end
 
+
 local function dump(inputfile)
-  local reader = bufread.new(inputfile)
-  local symbols = symtab.parse(reader)
-  local events = sysprof.parse(reader, symbols)
+  -- XXX: This function exits with a non-zero exit code and
+  -- prints an error message if it encounters any failure during
+  -- the process of parsing.
+  local events = reader(inputfile, sysprof.parse)
 
   for stack, count in pairs(events) do
     print(stack, count)

tools/sysprof/parse.lua

@@ -237,7 +237,7 @@ function M.parse(reader, symbols)
   local _ = reader:read_octets(3)
 
   if magic ~= LJP_MAGIC then
-    error("Bad LJP format prologue: "..magic)
+    error("Bad LJP format prologue: " .. tostring(magic))
   end
 
   if string.byte(version) ~= LJP_CURRENT_VERSION then

tools/utils/profile_data_reader.lua

@@ -0,0 +1,33 @@
+local bufread = require('utils.bufread')
+local symtab = require('utils.symtab')
+
+local function make_xpcall_handler(inputfile, fmt)
+  return function()
+    io.stderr:write(string.format(fmt, inputfile))
+    os.exit(1, true)
+  end
+end
+
+local function safe_event_reader(inputfile, parser)
+  local _, reader = xpcall(
+    bufread.new,
+    make_xpcall_handler(inputfile, 'Failed to open %s.'),
+    inputfile
+  )
+
+  local _, symbols = xpcall(
+    symtab.parse,
+    make_xpcall_handler(inputfile, 'Failed to parse symtab from %s.'),
+    reader
+  )
+
+  local _, events = xpcall(
+    parser,
+    make_xpcall_handler(inputfile, 'Failed to parse profile data from %s.'),
+    reader,
+    symbols
+  )
+  return events, symbols
+end
+
+return safe_event_reader

tools/utils/symtab.lua

@@ -95,7 +95,7 @@ function M.parse(reader)
   local _ = reader:read_octets(3)
 
   if magic ~= LJS_MAGIC then
-    error("Bad LJS format prologue: "..magic)
+    error("Bad LJS format prologue: " .. tostring(magic))
   end
 
   if string.byte(version) ~= LJS_CURRENT_VERSION then