perf tools: Simplify debugfs mountpoint handling code

We don't need to have two PATH_MAX char sized arrays holding it, just
one in util/debugfs.c will do.

Also rename debugfs_path to tracing_events_path, as it is not the path
to debugfs, that is debugfs_mountpoint. Both are now accessible.

This will allow accessing this code in the perf python binding without
having to drag in perf.c and util/parse-events.c.

The defaults for these variables are the canonical "/sys/kernel/debug"
and "/sys/kernel/debug/tracing/events/", removing the need for simple
tools to call debugfs_mount(NULL).

Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-ug9jvtjrsqbluuhqqxpvg30f@git.kernel.orgSigned-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent c168fbfb
......@@ -7,6 +7,7 @@
#include "util/cache.h"
#include "util/debug.h"
#include "util/debugfs.h"
#include "util/evlist.h"
#include "util/parse-options.h"
#include "util/parse-events.h"
......@@ -247,7 +248,7 @@ static int trace_event__id(const char *evname)
if (asprintf(&filename,
"%s/syscalls/%s/id",
debugfs_path, evname) < 0)
tracing_events_path, evname) < 0)
return -1;
fd = open(filename, O_RDONLY);
......
......@@ -29,8 +29,6 @@ struct pager_config {
int val;
};
static char debugfs_mntpt[MAXPATHLEN];
static int pager_command_config(const char *var, const char *value, void *data)
{
struct pager_config *c = data;
......@@ -81,15 +79,6 @@ static void commit_pager_choice(void)
}
}
static void set_debugfs_path(void)
{
char *path;
path = getenv(PERF_DEBUGFS_ENVIRONMENT);
snprintf(debugfs_path, MAXPATHLEN, "%s/%s", path ?: debugfs_mntpt,
"tracing/events");
}
static int handle_options(const char ***argv, int *argc, int *envchanged)
{
int handled = 0;
......@@ -161,15 +150,14 @@ static int handle_options(const char ***argv, int *argc, int *envchanged)
fprintf(stderr, "No directory given for --debugfs-dir.\n");
usage(perf_usage_string);
}
strncpy(debugfs_mntpt, (*argv)[1], MAXPATHLEN);
debugfs_mntpt[MAXPATHLEN - 1] = '\0';
debugfs_set_path((*argv)[1]);
if (envchanged)
*envchanged = 1;
(*argv)++;
(*argc)--;
} else if (!prefixcmp(cmd, CMD_DEBUGFS_DIR)) {
strncpy(debugfs_mntpt, cmd + strlen(CMD_DEBUGFS_DIR), MAXPATHLEN);
debugfs_mntpt[MAXPATHLEN - 1] = '\0';
debugfs_set_path(cmd + strlen(CMD_DEBUGFS_DIR));
fprintf(stderr, "dir: %s\n", debugfs_mountpoint);
if (envchanged)
*envchanged = 1;
} else {
......@@ -281,7 +269,6 @@ static int run_builtin(struct cmd_struct *p, int argc, const char **argv)
if (use_pager == -1 && p->option & USE_PAGER)
use_pager = 1;
commit_pager_choice();
set_debugfs_path();
status = p->fn(argc, argv, prefix);
exit_browser(status);
......@@ -416,17 +403,6 @@ static int run_argv(int *argcp, const char ***argv)
return done_alias;
}
/* mini /proc/mounts parser: searching for "^blah /mount/point debugfs" */
static void get_debugfs_mntpt(void)
{
const char *path = debugfs_mount(NULL);
if (path)
strncpy(debugfs_mntpt, path, sizeof(debugfs_mntpt));
else
debugfs_mntpt[0] = '\0';
}
static void pthread__block_sigwinch(void)
{
sigset_t set;
......@@ -453,7 +429,7 @@ int main(int argc, const char **argv)
if (!cmd)
cmd = "perf-help";
/* get debugfs mount point from /proc/mounts */
get_debugfs_mntpt();
debugfs_mount(NULL);
/*
* "perf-xxxx" is the same as "perf xxxx", but we obviously:
*
......@@ -476,7 +452,6 @@ int main(int argc, const char **argv)
argc--;
handle_options(&argv, &argc, NULL);
commit_pager_choice();
set_debugfs_path();
set_buildid_dir();
if (argc > 0) {
......
......@@ -2,10 +2,12 @@
#include "debugfs.h"
#include "cache.h"
#include <linux/kernel.h>
#include <sys/mount.h>
static int debugfs_premounted;
static char debugfs_mountpoint[PATH_MAX + 1];
char debugfs_mountpoint[PATH_MAX + 1] = "/sys/kernel/debug";
char tracing_events_path[PATH_MAX + 1] = "/sys/kernel/debug/tracing/events";
static const char *debugfs_known_mountpoints[] = {
"/sys/kernel/debug/",
......@@ -64,7 +66,7 @@ const char *debugfs_find_mountpoint(void)
/* give up and parse /proc/mounts */
fp = fopen("/proc/mounts", "r");
if (fp == NULL)
die("Can't open /proc/mounts for read");
return NULL;
while (fscanf(fp, "%*s %" STR(PATH_MAX) "s %99s %*s %*d %*d\n",
debugfs_mountpoint, type) == 2) {
......@@ -106,6 +108,12 @@ int debugfs_valid_entry(const char *path)
return 0;
}
static void debugfs_set_tracing_events_path(const char *mountpoint)
{
snprintf(tracing_events_path, sizeof(tracing_events_path), "%s/%s",
mountpoint, "tracing/events");
}
/* mount the debugfs somewhere if it's not mounted */
char *debugfs_mount(const char *mountpoint)
......@@ -113,7 +121,7 @@ char *debugfs_mount(const char *mountpoint)
/* see if it's already mounted */
if (debugfs_find_mountpoint()) {
debugfs_premounted = 1;
return debugfs_mountpoint;
goto out;
}
/* if not mounted and no argument */
......@@ -129,12 +137,19 @@ char *debugfs_mount(const char *mountpoint)
return NULL;
/* save the mountpoint */
strncpy(debugfs_mountpoint, mountpoint, sizeof(debugfs_mountpoint));
debugfs_found = 1;
strncpy(debugfs_mountpoint, mountpoint, sizeof(debugfs_mountpoint));
out:
debugfs_set_tracing_events_path(debugfs_mountpoint);
return debugfs_mountpoint;
}
void debugfs_set_path(const char *mountpoint)
{
snprintf(debugfs_mountpoint, sizeof(debugfs_mountpoint), "%s", mountpoint);
debugfs_set_tracing_events_path(mountpoint);
}
/* umount the debugfs */
int debugfs_umount(void)
......
......@@ -6,9 +6,13 @@ int debugfs_valid_mountpoint(const char *debugfs);
int debugfs_valid_entry(const char *path);
char *debugfs_mount(const char *mountpoint);
int debugfs_umount(void);
void debugfs_set_path(const char *mountpoint);
int debugfs_write(const char *entry, const char *value);
int debugfs_read(const char *entry, char *buffer, size_t size);
void debugfs_force_cleanup(void);
int debugfs_make_path(const char *element, char *buffer, int size);
extern char debugfs_mountpoint[];
extern char tracing_events_path[];
#endif /* __DEBUGFS_H__ */
......@@ -25,8 +25,6 @@ enum event_result {
EVT_HANDLED_ALL
};
char debugfs_path[MAXPATHLEN];
#define CHW(x) .type = PERF_TYPE_HARDWARE, .config = PERF_COUNT_HW_##x
#define CSW(x) .type = PERF_TYPE_SOFTWARE, .config = PERF_COUNT_SW_##x
......@@ -140,7 +138,7 @@ static int tp_event_has_id(struct dirent *sys_dir, struct dirent *evt_dir)
char evt_path[MAXPATHLEN];
int fd;
snprintf(evt_path, MAXPATHLEN, "%s/%s/%s/id", debugfs_path,
snprintf(evt_path, MAXPATHLEN, "%s/%s/%s/id", tracing_events_path,
sys_dir->d_name, evt_dir->d_name);
fd = open(evt_path, O_RDONLY);
if (fd < 0)
......@@ -171,16 +169,16 @@ struct tracepoint_path *tracepoint_id_to_path(u64 config)
char evt_path[MAXPATHLEN];
char dir_path[MAXPATHLEN];
if (debugfs_valid_mountpoint(debugfs_path))
if (debugfs_valid_mountpoint(tracing_events_path))
return NULL;
sys_dir = opendir(debugfs_path);
sys_dir = opendir(tracing_events_path);
if (!sys_dir)
return NULL;
for_each_subsystem(sys_dir, sys_dirent, sys_next) {
snprintf(dir_path, MAXPATHLEN, "%s/%s", debugfs_path,
snprintf(dir_path, MAXPATHLEN, "%s/%s", tracing_events_path,
sys_dirent.d_name);
evt_dir = opendir(dir_path);
if (!evt_dir)
......@@ -447,7 +445,7 @@ parse_single_tracepoint_event(char *sys_name,
u64 id;
int fd;
snprintf(evt_path, MAXPATHLEN, "%s/%s/%s/id", debugfs_path,
snprintf(evt_path, MAXPATHLEN, "%s/%s/%s/id", tracing_events_path,
sys_name, evt_name);
fd = open(evt_path, O_RDONLY);
......@@ -485,7 +483,7 @@ parse_multiple_tracepoint_event(struct perf_evlist *evlist, char *sys_name,
struct dirent *evt_ent;
DIR *evt_dir;
snprintf(evt_path, MAXPATHLEN, "%s/%s", debugfs_path, sys_name);
snprintf(evt_path, MAXPATHLEN, "%s/%s", tracing_events_path, sys_name);
evt_dir = opendir(evt_path);
if (!evt_dir) {
......@@ -528,7 +526,7 @@ parse_tracepoint_event(struct perf_evlist *evlist, const char **strp,
char sys_name[MAX_EVENT_LENGTH];
unsigned int sys_length, evt_length;
if (debugfs_valid_mountpoint(debugfs_path))
if (debugfs_valid_mountpoint(tracing_events_path))
return 0;
evt_name = strchr(*strp, ':');
......@@ -920,10 +918,10 @@ void print_tracepoint_events(const char *subsys_glob, const char *event_glob)
char evt_path[MAXPATHLEN];
char dir_path[MAXPATHLEN];
if (debugfs_valid_mountpoint(debugfs_path))
if (debugfs_valid_mountpoint(tracing_events_path))
return;
sys_dir = opendir(debugfs_path);
sys_dir = opendir(tracing_events_path);
if (!sys_dir)
return;
......@@ -932,7 +930,7 @@ void print_tracepoint_events(const char *subsys_glob, const char *event_glob)
!strglobmatch(sys_dirent.d_name, subsys_glob))
continue;
snprintf(dir_path, MAXPATHLEN, "%s/%s", debugfs_path,
snprintf(dir_path, MAXPATHLEN, "%s/%s", tracing_events_path,
sys_dirent.d_name);
evt_dir = opendir(dir_path);
if (!evt_dir)
......@@ -964,16 +962,16 @@ int is_valid_tracepoint(const char *event_string)
char evt_path[MAXPATHLEN];
char dir_path[MAXPATHLEN];
if (debugfs_valid_mountpoint(debugfs_path))
if (debugfs_valid_mountpoint(tracing_events_path))
return 0;
sys_dir = opendir(debugfs_path);
sys_dir = opendir(tracing_events_path);
if (!sys_dir)
return 0;
for_each_subsystem(sys_dir, sys_dirent, sys_next) {
snprintf(dir_path, MAXPATHLEN, "%s/%s", debugfs_path,
snprintf(dir_path, MAXPATHLEN, "%s/%s", tracing_events_path,
sys_dirent.d_name);
evt_dir = opendir(dir_path);
if (!evt_dir)
......
......@@ -39,7 +39,6 @@ void print_tracepoint_events(const char *subsys_glob, const char *event_glob);
int print_hwcache_events(const char *event_glob);
extern int is_valid_tracepoint(const char *event_string);
extern char debugfs_path[];
extern int valid_debugfs_mount(const char *debugfs);
#endif /* __PERF_PARSE_EVENTS_H */
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