tor/scripts/coccinelle/debugmm.cocci

// Look for use of expressions with side-effects inside of debug logs.
//
// This script detects expressions like ++E, --E, E++, and E-- inside of
// calls to log_debug().
//
// The log_debug() macro exits early if debug logging is not enabled,
// potentially causing problems if its arguments have side-effects.

@@
expression E;
@@
*log_debug(... , <+...  --E ...+>, ... );


@@
expression E;
@@
*log_debug(... , <+...  ++E ...+>, ... );

@@
expression E;
@@
*log_debug(... , <+...  E-- ...+>, ... );


@@
expression E;
@@
*log_debug(... , <+...  E++ ...+>, ... );
Add a coccinelle script to look for {inc,dec}rements in log_debug We want to forbid this pattern since, unlike the other log_*() macros, log_debug() conditionally evaluates its arguments only if debug-level logging is enabled. Thus, a call to log_debug("%d", x++); will only increment x if debugging logs are enabled, which is probably not what the programmer intended. One bug caused by this pattern was #30628. This script detects log_debug( ) calls with any of E++, E--, ++E, or --E in their arguments, where E is an arbitrary expression. Closes ticket 30743. 2019-09-12 00:53:16 +02:00			`// Look for use of expressions with side-effects inside of debug logs.`
			`//`
			`// This script detects expressions like ++E, --E, E++, and E-- inside of`
			`// calls to log_debug().`
			`//`
			`// The log_debug() macro exits early if debug logging is not enabled,`
			`// potentially causing problems if its arguments have side-effects.`

			`@@`
			`expression E;`
			`@@`
			`*log_debug(... , <+... --E ...+>, ... );`


			`@@`
			`expression E;`
			`@@`
			`*log_debug(... , <+... ++E ...+>, ... );`

			`@@`
			`expression E;`
			`@@`
			`*log_debug(... , <+... E-- ...+>, ... );`


			`@@`
			`expression E;`
			`@@`
			`*log_debug(... , <+... E++ ...+>, ... );`