Commit 8ece26ad authored by Ian Rogers's avatar Ian Rogers Committed by Namhyung Kim
Browse files

perf list: Add scandirat compatibility function 



scandirat is used during the printing of tracepoint events but may be
missing from certain libcs. Add a compatibility implementation that
uses the symlink of an fd in /proc as a path for the reliably present
scandir.

Signed-off-by: default avatarIan Rogers <irogers@google.com>
Cc: James Clark <james.clark@arm.com>
Cc: Justin Stitt <justinstitt@google.com>
Cc: Bill Wendling <morbo@google.com>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Yang Jihong <yangjihong1@huawei.com>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Athira Jajeev <atrajeev@linux.vnet.ibm.com>
Cc: llvm@lists.linux.dev
Signed-off-by: default avatarNamhyung Kim <namhyung@kernel.org>
Link: https://lore.kernel.org/r/20240221034155.1500118-3-irogers@google.com
parent 510e5287

tools/perf/util/print-events.c

+4 −9
Original line number Diff line number Diff line
@@ -28,6 +28,7 @@ 
#include "tracepoint.h"

#include "pfm.h"

#include "thread_map.h"

#include "util.h"



#define MAX_NAME_LEN 100
@@ -63,6 +64,8 @@ void print_tracepoint_events(const struct print_callbacks *print_cb __maybe_unus 
{

	char *events_path = get_tracing_file("events");

	int events_fd = open(events_path, O_PATH);

	struct dirent **sys_namelist = NULL;

	int sys_items;



	put_tracing_file(events_path);

	if (events_fd < 0) {
@@ -70,10 +73,7 @@ void print_tracepoint_events(const struct print_callbacks *print_cb __maybe_unus 
		return;

	}



#ifdef HAVE_SCANDIRAT_SUPPORT

{

	struct dirent **sys_namelist = NULL;

	int sys_items = tracing_events__scandir_alphasort(&sys_namelist);

	sys_items = tracing_events__scandir_alphasort(&sys_namelist);



	for (int i = 0; i < sys_items; i++) {

		struct dirent *sys_dirent = sys_namelist[i];
@@ -130,11 +130,6 @@ void print_tracepoint_events(const struct print_callbacks *print_cb __maybe_unus 
	}



	free(sys_namelist);

}

#else

	printf("\nWARNING: Your libc doesn't have the scandirat function, please ask its maintainers to implement it.\n"

	       "         As a rough fallback, please do 'ls %s' to see the available tracepoint events.\n", events_path);

#endif

	close(events_fd);

}

tools/perf/util/util.c

+19 −0
Original line number Diff line number Diff line
@@ -552,3 +552,22 @@ int sched_getcpu(void) 
	return -1;

}

#endif



#ifndef HAVE_SCANDIRAT_SUPPORT

int scandirat(int dirfd, const char *dirp,

	      struct dirent ***namelist,

	      int (*filter)(const struct dirent *),

	      int (*compar)(const struct dirent **, const struct dirent **))

{

	char path[PATH_MAX];

	int err, fd = openat(dirfd, dirp, O_PATH);



	if (fd < 0)

		return fd;



	snprintf(path, sizeof(path), "/proc/%d/fd/%d", getpid(), fd);

	err = scandir(path, namelist, filter, compar);

	close(fd);

	return err;

}

#endif

tools/perf/util/util.h

+8 −0
Original line number Diff line number Diff line
@@ -6,6 +6,7 @@ 
/* glibc 2.20 deprecates _BSD_SOURCE in favour of _DEFAULT_SOURCE */

#define _DEFAULT_SOURCE 1



#include <dirent.h>

#include <fcntl.h>

#include <stdbool.h>

#include <stddef.h>
@@ -56,6 +57,13 @@ int perf_tip(char **strp, const char *dirpath); 
int sched_getcpu(void);

#endif



#ifndef HAVE_SCANDIRAT_SUPPORT

int scandirat(int dirfd, const char *dirp,

	      struct dirent ***namelist,

	      int (*filter)(const struct dirent *),

	      int (*compar)(const struct dirent **, const struct dirent **));

#endif



extern bool perf_singlethreaded;



void perf_set_singlethreaded(void);