Re: [PATCH v3] perf probe: Find compilation directory path for lazy matching

[Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>]

(2015/03/13 14:18), Naohiro Aota wrote:
> If we use lazy matching, it failed to open a souce file if perf command
> is invoked outside of compilation directory:
> 
> $ perf probe -a '__schedule;clear_*'
> Failed to open kernel/sched/core.c: No such file or directory
>   Error: Failed to add events. (-2)
> 
> OTOH, other commands like "probe -L" can solve the souce directory by
> themselves. Let's make it possible for lazy matching too!
> 

Ok, I've built and tested it.
----
[mhiramat@localhost opt]$ sudo /home/mhiramat/ksrc/linux-3/tools/perf/perf probe -fna '__schedule;clear_*'
Added new event:
  probe:__schedule     (on __schedule)

You can now use it in all perf tools, such as:

        perf record -e probe:__schedule -aR sleep 1

----
So now it can go :)

Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>


Thank you!

> Signed-off-by: Naohiro Aota <naota@elisp.net>
> ---
>  tools/perf/util/probe-event.c  | 59 -----------------------------------
>  tools/perf/util/probe-finder.c | 71 +++++++++++++++++++++++++++++++++++++++++-
>  tools/perf/util/probe-finder.h |  4 +++
>  3 files changed, 74 insertions(+), 60 deletions(-)
> 
> diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
> index f272a71..32a429b 100644
> --- a/tools/perf/util/probe-event.c
> +++ b/tools/perf/util/probe-event.c
> @@ -648,65 +648,6 @@ static int try_to_find_probe_trace_events(struct perf_probe_event *pev,
>  	return ntevs;
>  }
>  
> -/*
> - * Find a src file from a DWARF tag path. Prepend optional source path prefix
> - * and chop off leading directories that do not exist. Result is passed back as
> - * a newly allocated path on success.
> - * Return 0 if file was found and readable, -errno otherwise.
> - */
> -static int get_real_path(const char *raw_path, const char *comp_dir,
> -			 char **new_path)
> -{
> -	const char *prefix = symbol_conf.source_prefix;
> -
> -	if (!prefix) {
> -		if (raw_path[0] != '/' && comp_dir)
> -			/* If not an absolute path, try to use comp_dir */
> -			prefix = comp_dir;
> -		else {
> -			if (access(raw_path, R_OK) == 0) {
> -				*new_path = strdup(raw_path);
> -				return *new_path ? 0 : -ENOMEM;
> -			} else
> -				return -errno;
> -		}
> -	}
> -
> -	*new_path = malloc((strlen(prefix) + strlen(raw_path) + 2));
> -	if (!*new_path)
> -		return -ENOMEM;
> -
> -	for (;;) {
> -		sprintf(*new_path, "%s/%s", prefix, raw_path);
> -
> -		if (access(*new_path, R_OK) == 0)
> -			return 0;
> -
> -		if (!symbol_conf.source_prefix) {
> -			/* In case of searching comp_dir, don't retry */
> -			zfree(new_path);
> -			return -errno;
> -		}
> -
> -		switch (errno) {
> -		case ENAMETOOLONG:
> -		case ENOENT:
> -		case EROFS:
> -		case EFAULT:
> -			raw_path = strchr(++raw_path, '/');
> -			if (!raw_path) {
> -				zfree(new_path);
> -				return -ENOENT;
> -			}
> -			continue;
> -
> -		default:
> -			zfree(new_path);
> -			return -errno;
> -		}
> -	}
> -}
> -
>  #define LINEBUF_SIZE 256
>  #define NR_ADDITIONAL_LINES 2
>  
> diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c
> index 46f009a..0fd2df4 100644
> --- a/tools/perf/util/probe-finder.c
> +++ b/tools/perf/util/probe-finder.c
> @@ -849,11 +849,22 @@ static int probe_point_lazy_walker(const char *fname, int lineno,
>  static int find_probe_point_lazy(Dwarf_Die *sp_die, struct probe_finder *pf)
>  {
>  	int ret = 0;
> +	char *fpath;
>  
>  	if (intlist__empty(pf->lcache)) {
> +		const char *comp_dir;
> +
> +		comp_dir = cu_get_comp_dir(&pf->cu_die);
> +		ret = get_real_path(pf->fname, comp_dir, &fpath);
> +		if (ret < 0) {
> +			pr_warning("Failed to find source file path.\n");
> +			return ret;
> +		}
> +
>  		/* Matching lazy line pattern */
> -		ret = find_lazy_match_lines(pf->lcache, pf->fname,
> +		ret = find_lazy_match_lines(pf->lcache, fpath,
>  					    pf->pev->point.lazy_line);
> +		free(fpath);
>  		if (ret <= 0)
>  			return ret;
>  	}
> @@ -1616,3 +1627,61 @@ found:
>  	return (ret < 0) ? ret : lf.found;
>  }
>  
> +/*
> + * Find a src file from a DWARF tag path. Prepend optional source path prefix
> + * and chop off leading directories that do not exist. Result is passed back as
> + * a newly allocated path on success.
> + * Return 0 if file was found and readable, -errno otherwise.
> + */
> +int get_real_path(const char *raw_path, const char *comp_dir,
> +			 char **new_path)
> +{
> +	const char *prefix = symbol_conf.source_prefix;
> +
> +	if (!prefix) {
> +		if (raw_path[0] != '/' && comp_dir)
> +			/* If not an absolute path, try to use comp_dir */
> +			prefix = comp_dir;
> +		else {
> +			if (access(raw_path, R_OK) == 0) {
> +				*new_path = strdup(raw_path);
> +				return *new_path ? 0 : -ENOMEM;
> +			} else
> +				return -errno;
> +		}
> +	}
> +
> +	*new_path = malloc((strlen(prefix) + strlen(raw_path) + 2));
> +	if (!*new_path)
> +		return -ENOMEM;
> +
> +	for (;;) {
> +		sprintf(*new_path, "%s/%s", prefix, raw_path);
> +
> +		if (access(*new_path, R_OK) == 0)
> +			return 0;
> +
> +		if (!symbol_conf.source_prefix) {
> +			/* In case of searching comp_dir, don't retry */
> +			zfree(new_path);
> +			return -errno;
> +		}
> +
> +		switch (errno) {
> +		case ENAMETOOLONG:
> +		case ENOENT:
> +		case EROFS:
> +		case EFAULT:
> +			raw_path = strchr(++raw_path, '/');
> +			if (!raw_path) {
> +				zfree(new_path);
> +				return -ENOENT;
> +			}
> +			continue;
> +
> +		default:
> +			zfree(new_path);
> +			return -errno;
> +		}
> +	}
> +}
> diff --git a/tools/perf/util/probe-finder.h b/tools/perf/util/probe-finder.h
> index 92590b2..ebf8c8c 100644
> --- a/tools/perf/util/probe-finder.h
> +++ b/tools/perf/util/probe-finder.h
> @@ -55,6 +55,10 @@ extern int debuginfo__find_available_vars_at(struct debuginfo *dbg,
>  					     struct variable_list **vls,
>  					     int max_points, bool externs);
>  
> +/* Find a src file from a DWARF tag path */
> +int get_real_path(const char *raw_path, const char *comp_dir,
> +			 char **new_path);
> +
>  struct probe_finder {
>  	struct perf_probe_event	*pev;		/* Target probe event */
>  
> 


-- 
Masami HIRAMATSU
Software Platform Research Dept. Linux Technology Research Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: masami.hiramatsu.pt@hitachi.com