Skip to content

Latest commit

 

History

History
73 lines (59 loc) · 2.53 KB

07_maypanic.md

File metadata and controls

73 lines (59 loc) · 2.53 KB

May Panic Analysis

This analysis is not supported at the same level as the taint, backtrace and dependencies analyses. It is still included as users may find it useful.

The "may panic" analysis tool maypanic performs an analysis to determine whether each function that is launched as a goroutine recover()s all panics. Failure to recover from a panic in the top function of a goroutine will result in the Go runtime terminating the program. An example invocation is:

$ argot maypanic maypanic.go
Reading sources
Analyzing
unrecovered panic in command-line-arguments.callFunc
  command-line-arguments.callFunc
  maypanic.go:7:6
  created by maypanic.go:4:2
Found 1 unrecovered panics

The above output is a possible result if the maypanic.go file contains:

package main

func main() {
	go callFunc()
}

func callFunc() {
    // no recover()
	doPanic()
}

func doPanic() {
	panic("Panic in doPanic")
}

If we change callFunc() to:

func callFunc() {
	defer func() {
		if x := recover(); x != nil {
			// do nothing with error
		}
	}()
	doPanic()
}

then the error is considered handled. This tool does not enforce any particular action when recovering a panic, only that it is not allowed to be propagated to the root of the goroutine. This tool also does not enforce that code that recovers (or further deferred actions) does not panic; thus recovery code that panics may still cause program termination.

Running the maypanic tool

The maypanic function takes options, followed by the go files to analyze.

maypanic [OPTIONS] source.go
maypanic [OPTIONS] source1.go source2.go
maypanic [OPTIONS] package...

The use with packages requires the packages to be accessible on the GOPATH.

The command may be prefixed with assignments GOOS and/or GOARCH to analyze a different architecture:

GOOS=windows GOARCH=amd64 argot maypanic source.go

Options

Options that may be passed to maypanic:

  • -exclude PATH Path to exclude from analysis. May be supplied multiple times to ignore multiple paths.
  • -json Output results as a list of JSON objects. Example:
[{"Description":"unrecovered panic","GoRoutine":{"Function":"command-line-arguments.callFunc","Filename":"maypanic.go","Line":7,"Column":6},"Creators":[{"Function":"","Filename":"maypanic.go","Line":4,"Column":2}]}]
  • -tags TAGS... A list of build tags to consider satisfied during the build. For more information about build tags, see the description of build constraints in the documentation for the go/build package