linux/tools/perf/util/config.c

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/*
* GIT - The information manager from hell
*
* Copyright (C) Linus Torvalds, 2005
* Copyright (C) Johannes Schindelin, 2005
*
*/
#include "util.h"
#include "cache.h"
#include "exec_cmd.h"
#define MAXNAME (256)
perf buildid: add perfconfig option to specify buildid cache dir This patch adds the ability to specify an alternate directory to store the buildid cache (buildids, copy of binaries). By default, it is hardcoded to $HOME/.debug. This directory contains immutable data. The layout of the directory is such that no conflicts in filenames are possible. A modification in a file, yields a different buildid and thus a different location in the subdir hierarchy. You may want to put the buildid cache elsewhere because of disk space limitation or simply to share the cache between users. It is also useful for remote collect vs. local analysis of profiles. This patch adds a new config option to the perfconfig file. Under the tag 'buildid', there is a dir option. For instance, if you have: $ cat /etc/perfconfig [buildid] dir = /var/cache/perf-buildid All buildids and binaries are be saved in the directory specified. The perf record, buildid-list, buildid-cache, report, annotate, and archive commands will it to pull information out. The option can be set in the system-wide perfconfig file or in the $HOME/.perfconfig file. Cc: David S. Miller <davem@davemloft.net> Cc: Frédéric Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Cc: Tom Zanussi <tzanussi@gmail.com> LKML-Reference: <4c055fb7.df0ce30a.5f0d.ffffae52@mx.google.com> Signed-off-by: Stephane Eranian <eranian@google.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2010-06-01 19:25:01 +00:00
#define DEBUG_CACHE_DIR ".debug"
char buildid_dir[MAXPATHLEN]; /* root dir for buildid, binary cache */
static FILE *config_file;
static const char *config_file_name;
static int config_linenr;
static int config_file_eof;
static const char *config_exclusive_filename;
static int get_next_char(void)
{
int c;
FILE *f;
c = '\n';
if ((f = config_file) != NULL) {
c = fgetc(f);
if (c == '\r') {
/* DOS like systems */
c = fgetc(f);
if (c != '\n') {
ungetc(c, f);
c = '\r';
}
}
if (c == '\n')
config_linenr++;
if (c == EOF) {
config_file_eof = 1;
c = '\n';
}
}
return c;
}
static char *parse_value(void)
{
static char value[1024];
int quote = 0, comment = 0, space = 0;
size_t len = 0;
for (;;) {
int c = get_next_char();
if (len >= sizeof(value) - 1)
return NULL;
if (c == '\n') {
if (quote)
return NULL;
value[len] = 0;
return value;
}
if (comment)
continue;
if (isspace(c) && !quote) {
space = 1;
continue;
}
if (!quote) {
if (c == ';' || c == '#') {
comment = 1;
continue;
}
}
if (space) {
if (len)
value[len++] = ' ';
space = 0;
}
if (c == '\\') {
c = get_next_char();
switch (c) {
case '\n':
continue;
case 't':
c = '\t';
break;
case 'b':
c = '\b';
break;
case 'n':
c = '\n';
break;
/* Some characters escape as themselves */
case '\\': case '"':
break;
/* Reject unknown escape sequences */
default:
return NULL;
}
value[len++] = c;
continue;
}
if (c == '"') {
quote = 1-quote;
continue;
}
value[len++] = c;
}
}
static inline int iskeychar(int c)
{
return isalnum(c) || c == '-';
}
static int get_value(config_fn_t fn, void *data, char *name, unsigned int len)
{
int c;
char *value;
/* Get the full name */
for (;;) {
c = get_next_char();
if (config_file_eof)
break;
if (!iskeychar(c))
break;
perf buildid: add perfconfig option to specify buildid cache dir This patch adds the ability to specify an alternate directory to store the buildid cache (buildids, copy of binaries). By default, it is hardcoded to $HOME/.debug. This directory contains immutable data. The layout of the directory is such that no conflicts in filenames are possible. A modification in a file, yields a different buildid and thus a different location in the subdir hierarchy. You may want to put the buildid cache elsewhere because of disk space limitation or simply to share the cache between users. It is also useful for remote collect vs. local analysis of profiles. This patch adds a new config option to the perfconfig file. Under the tag 'buildid', there is a dir option. For instance, if you have: $ cat /etc/perfconfig [buildid] dir = /var/cache/perf-buildid All buildids and binaries are be saved in the directory specified. The perf record, buildid-list, buildid-cache, report, annotate, and archive commands will it to pull information out. The option can be set in the system-wide perfconfig file or in the $HOME/.perfconfig file. Cc: David S. Miller <davem@davemloft.net> Cc: Frédéric Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Cc: Tom Zanussi <tzanussi@gmail.com> LKML-Reference: <4c055fb7.df0ce30a.5f0d.ffffae52@mx.google.com> Signed-off-by: Stephane Eranian <eranian@google.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2010-06-01 19:25:01 +00:00
name[len++] = c;
if (len >= MAXNAME)
return -1;
}
name[len] = 0;
while (c == ' ' || c == '\t')
c = get_next_char();
value = NULL;
if (c != '\n') {
if (c != '=')
return -1;
value = parse_value();
if (!value)
return -1;
}
return fn(name, value, data);
}
static int get_extended_base_var(char *name, int baselen, int c)
{
do {
if (c == '\n')
return -1;
c = get_next_char();
} while (isspace(c));
/* We require the format to be '[base "extension"]' */
if (c != '"')
return -1;
name[baselen++] = '.';
for (;;) {
perf: Enable more compiler warnings Related to a shadowed variable bug fix Valdis Kletnieks noticed that perf does not get built with -Wshadow, which could have helped us avoid the bug. So enable -Wshadow and also enable the following warnings on perf builds, in addition to the already enabled -Wall -Wextra -std=gnu99 warnings: -Wcast-align -Wformat=2 -Wshadow -Winit-self -Wpacked -Wredundant-decls -Wstack-protector -Wstrict-aliasing=3 -Wswitch-default -Wswitch-enum -Wno-system-headers -Wundef -Wvolatile-register-var -Wwrite-strings -Wbad-function-cast -Wmissing-declarations -Wmissing-prototypes -Wnested-externs -Wold-style-definition -Wstrict-prototypes -Wdeclaration-after-statement And change/fix the perf code to build cleanly under GCC 4.3.2. The list of warnings enablement is rather arbitrary: it's based on my (quick) reading of the GCC manpages and trying them on perf. I categorized the warnings based on individually enabling them and looking whether they trigger something in the perf build. If i liked those warnings (i.e. if they trigger for something that arguably could be improved) i enabled the warning. If the warnings seemed to come from language laywers spamming the build with tons of nuisance warnings i generally kept them off. Most of the sign conversion related warnings were in this category. (A second patch enabling some of the sign warnings might be welcome - sign bugs can be nasty.) I also kept warnings that seem to make sense from their manpage description and which produced no actual warnings on our code base. These warnings might still be turned off if they end up being a nuisance. I also left out a few warnings that are not supported in older compilers. [ Note that these changes might break the build on older compilers i did not test, or on non-x86 architectures that produce different warnings, so more testing would be welcome. ] Reported-by: Valdis.Kletnieks@vt.edu Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Mike Galbraith <efault@gmx.de> Cc: Paul Mackerras <paulus@samba.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> LKML-Reference: <new-submission> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-08-15 10:26:57 +00:00
int ch = get_next_char();
if (ch == '\n')
return -1;
perf: Enable more compiler warnings Related to a shadowed variable bug fix Valdis Kletnieks noticed that perf does not get built with -Wshadow, which could have helped us avoid the bug. So enable -Wshadow and also enable the following warnings on perf builds, in addition to the already enabled -Wall -Wextra -std=gnu99 warnings: -Wcast-align -Wformat=2 -Wshadow -Winit-self -Wpacked -Wredundant-decls -Wstack-protector -Wstrict-aliasing=3 -Wswitch-default -Wswitch-enum -Wno-system-headers -Wundef -Wvolatile-register-var -Wwrite-strings -Wbad-function-cast -Wmissing-declarations -Wmissing-prototypes -Wnested-externs -Wold-style-definition -Wstrict-prototypes -Wdeclaration-after-statement And change/fix the perf code to build cleanly under GCC 4.3.2. The list of warnings enablement is rather arbitrary: it's based on my (quick) reading of the GCC manpages and trying them on perf. I categorized the warnings based on individually enabling them and looking whether they trigger something in the perf build. If i liked those warnings (i.e. if they trigger for something that arguably could be improved) i enabled the warning. If the warnings seemed to come from language laywers spamming the build with tons of nuisance warnings i generally kept them off. Most of the sign conversion related warnings were in this category. (A second patch enabling some of the sign warnings might be welcome - sign bugs can be nasty.) I also kept warnings that seem to make sense from their manpage description and which produced no actual warnings on our code base. These warnings might still be turned off if they end up being a nuisance. I also left out a few warnings that are not supported in older compilers. [ Note that these changes might break the build on older compilers i did not test, or on non-x86 architectures that produce different warnings, so more testing would be welcome. ] Reported-by: Valdis.Kletnieks@vt.edu Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Mike Galbraith <efault@gmx.de> Cc: Paul Mackerras <paulus@samba.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> LKML-Reference: <new-submission> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-08-15 10:26:57 +00:00
if (ch == '"')
break;
perf: Enable more compiler warnings Related to a shadowed variable bug fix Valdis Kletnieks noticed that perf does not get built with -Wshadow, which could have helped us avoid the bug. So enable -Wshadow and also enable the following warnings on perf builds, in addition to the already enabled -Wall -Wextra -std=gnu99 warnings: -Wcast-align -Wformat=2 -Wshadow -Winit-self -Wpacked -Wredundant-decls -Wstack-protector -Wstrict-aliasing=3 -Wswitch-default -Wswitch-enum -Wno-system-headers -Wundef -Wvolatile-register-var -Wwrite-strings -Wbad-function-cast -Wmissing-declarations -Wmissing-prototypes -Wnested-externs -Wold-style-definition -Wstrict-prototypes -Wdeclaration-after-statement And change/fix the perf code to build cleanly under GCC 4.3.2. The list of warnings enablement is rather arbitrary: it's based on my (quick) reading of the GCC manpages and trying them on perf. I categorized the warnings based on individually enabling them and looking whether they trigger something in the perf build. If i liked those warnings (i.e. if they trigger for something that arguably could be improved) i enabled the warning. If the warnings seemed to come from language laywers spamming the build with tons of nuisance warnings i generally kept them off. Most of the sign conversion related warnings were in this category. (A second patch enabling some of the sign warnings might be welcome - sign bugs can be nasty.) I also kept warnings that seem to make sense from their manpage description and which produced no actual warnings on our code base. These warnings might still be turned off if they end up being a nuisance. I also left out a few warnings that are not supported in older compilers. [ Note that these changes might break the build on older compilers i did not test, or on non-x86 architectures that produce different warnings, so more testing would be welcome. ] Reported-by: Valdis.Kletnieks@vt.edu Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Mike Galbraith <efault@gmx.de> Cc: Paul Mackerras <paulus@samba.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> LKML-Reference: <new-submission> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-08-15 10:26:57 +00:00
if (ch == '\\') {
ch = get_next_char();
if (ch == '\n')
return -1;
}
perf: Enable more compiler warnings Related to a shadowed variable bug fix Valdis Kletnieks noticed that perf does not get built with -Wshadow, which could have helped us avoid the bug. So enable -Wshadow and also enable the following warnings on perf builds, in addition to the already enabled -Wall -Wextra -std=gnu99 warnings: -Wcast-align -Wformat=2 -Wshadow -Winit-self -Wpacked -Wredundant-decls -Wstack-protector -Wstrict-aliasing=3 -Wswitch-default -Wswitch-enum -Wno-system-headers -Wundef -Wvolatile-register-var -Wwrite-strings -Wbad-function-cast -Wmissing-declarations -Wmissing-prototypes -Wnested-externs -Wold-style-definition -Wstrict-prototypes -Wdeclaration-after-statement And change/fix the perf code to build cleanly under GCC 4.3.2. The list of warnings enablement is rather arbitrary: it's based on my (quick) reading of the GCC manpages and trying them on perf. I categorized the warnings based on individually enabling them and looking whether they trigger something in the perf build. If i liked those warnings (i.e. if they trigger for something that arguably could be improved) i enabled the warning. If the warnings seemed to come from language laywers spamming the build with tons of nuisance warnings i generally kept them off. Most of the sign conversion related warnings were in this category. (A second patch enabling some of the sign warnings might be welcome - sign bugs can be nasty.) I also kept warnings that seem to make sense from their manpage description and which produced no actual warnings on our code base. These warnings might still be turned off if they end up being a nuisance. I also left out a few warnings that are not supported in older compilers. [ Note that these changes might break the build on older compilers i did not test, or on non-x86 architectures that produce different warnings, so more testing would be welcome. ] Reported-by: Valdis.Kletnieks@vt.edu Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Mike Galbraith <efault@gmx.de> Cc: Paul Mackerras <paulus@samba.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> LKML-Reference: <new-submission> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-08-15 10:26:57 +00:00
name[baselen++] = ch;
if (baselen > MAXNAME / 2)
return -1;
}
/* Final ']' */
if (get_next_char() != ']')
return -1;
return baselen;
}
static int get_base_var(char *name)
{
int baselen = 0;
for (;;) {
int c = get_next_char();
if (config_file_eof)
return -1;
if (c == ']')
return baselen;
if (isspace(c))
return get_extended_base_var(name, baselen, c);
if (!iskeychar(c) && c != '.')
return -1;
if (baselen > MAXNAME / 2)
return -1;
name[baselen++] = tolower(c);
}
}
static int perf_parse_file(config_fn_t fn, void *data)
{
int comment = 0;
int baselen = 0;
static char var[MAXNAME];
/* U+FEFF Byte Order Mark in UTF8 */
static const unsigned char *utf8_bom = (unsigned char *) "\xef\xbb\xbf";
const unsigned char *bomptr = utf8_bom;
for (;;) {
int c = get_next_char();
if (bomptr && *bomptr) {
/* We are at the file beginning; skip UTF8-encoded BOM
* if present. Sane editors won't put this in on their
* own, but e.g. Windows Notepad will do it happily. */
if ((unsigned char) c == *bomptr) {
bomptr++;
continue;
} else {
/* Do not tolerate partial BOM. */
if (bomptr != utf8_bom)
break;
/* No BOM at file beginning. Cool. */
bomptr = NULL;
}
}
if (c == '\n') {
if (config_file_eof)
return 0;
comment = 0;
continue;
}
if (comment || isspace(c))
continue;
if (c == '#' || c == ';') {
comment = 1;
continue;
}
if (c == '[') {
baselen = get_base_var(var);
if (baselen <= 0)
break;
var[baselen++] = '.';
var[baselen] = 0;
continue;
}
if (!isalpha(c))
break;
var[baselen] = tolower(c);
if (get_value(fn, data, var, baselen+1) < 0)
break;
}
die("bad config file line %d in %s", config_linenr, config_file_name);
}
static int parse_unit_factor(const char *end, unsigned long *val)
{
if (!*end)
return 1;
else if (!strcasecmp(end, "k")) {
*val *= 1024;
return 1;
}
else if (!strcasecmp(end, "m")) {
*val *= 1024 * 1024;
return 1;
}
else if (!strcasecmp(end, "g")) {
*val *= 1024 * 1024 * 1024;
return 1;
}
return 0;
}
static int perf_parse_long(const char *value, long *ret)
{
if (value && *value) {
char *end;
long val = strtol(value, &end, 0);
unsigned long factor = 1;
if (!parse_unit_factor(end, &factor))
return 0;
*ret = val * factor;
return 1;
}
return 0;
}
static void die_bad_config(const char *name)
{
if (config_file_name)
die("bad config value for '%s' in %s", name, config_file_name);
die("bad config value for '%s'", name);
}
int perf_config_int(const char *name, const char *value)
{
long ret = 0;
if (!perf_parse_long(value, &ret))
die_bad_config(name);
return ret;
}
static int perf_config_bool_or_int(const char *name, const char *value, int *is_bool)
{
*is_bool = 1;
if (!value)
return 1;
if (!*value)
return 0;
if (!strcasecmp(value, "true") || !strcasecmp(value, "yes") || !strcasecmp(value, "on"))
return 1;
if (!strcasecmp(value, "false") || !strcasecmp(value, "no") || !strcasecmp(value, "off"))
return 0;
*is_bool = 0;
return perf_config_int(name, value);
}
int perf_config_bool(const char *name, const char *value)
{
int discard;
return !!perf_config_bool_or_int(name, value, &discard);
}
perf buildid: add perfconfig option to specify buildid cache dir This patch adds the ability to specify an alternate directory to store the buildid cache (buildids, copy of binaries). By default, it is hardcoded to $HOME/.debug. This directory contains immutable data. The layout of the directory is such that no conflicts in filenames are possible. A modification in a file, yields a different buildid and thus a different location in the subdir hierarchy. You may want to put the buildid cache elsewhere because of disk space limitation or simply to share the cache between users. It is also useful for remote collect vs. local analysis of profiles. This patch adds a new config option to the perfconfig file. Under the tag 'buildid', there is a dir option. For instance, if you have: $ cat /etc/perfconfig [buildid] dir = /var/cache/perf-buildid All buildids and binaries are be saved in the directory specified. The perf record, buildid-list, buildid-cache, report, annotate, and archive commands will it to pull information out. The option can be set in the system-wide perfconfig file or in the $HOME/.perfconfig file. Cc: David S. Miller <davem@davemloft.net> Cc: Frédéric Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Cc: Tom Zanussi <tzanussi@gmail.com> LKML-Reference: <4c055fb7.df0ce30a.5f0d.ffffae52@mx.google.com> Signed-off-by: Stephane Eranian <eranian@google.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2010-06-01 19:25:01 +00:00
const char *perf_config_dirname(const char *name, const char *value)
{
if (!name)
return NULL;
return value;
}
static int perf_default_core_config(const char *var __used, const char *value __used)
{
/* Add other config variables here and to Documentation/config.txt. */
return 0;
}
int perf_default_config(const char *var, const char *value, void *dummy __used)
{
if (!prefixcmp(var, "core."))
return perf_default_core_config(var, value);
/* Add other config variables here and to Documentation/config.txt. */
return 0;
}
static int perf_config_from_file(config_fn_t fn, const char *filename, void *data)
{
int ret;
FILE *f = fopen(filename, "r");
ret = -1;
if (f) {
config_file = f;
config_file_name = filename;
config_linenr = 1;
config_file_eof = 0;
ret = perf_parse_file(fn, data);
fclose(f);
config_file_name = NULL;
}
return ret;
}
static const char *perf_etc_perfconfig(void)
{
static const char *system_wide;
if (!system_wide)
system_wide = system_path(ETC_PERFCONFIG);
return system_wide;
}
static int perf_env_bool(const char *k, int def)
{
const char *v = getenv(k);
return v ? perf_config_bool(k, v) : def;
}
static int perf_config_system(void)
{
return !perf_env_bool("PERF_CONFIG_NOSYSTEM", 0);
}
static int perf_config_global(void)
{
return !perf_env_bool("PERF_CONFIG_NOGLOBAL", 0);
}
int perf_config(config_fn_t fn, void *data)
{
int ret = 0, found = 0;
char *repo_config = NULL;
const char *home = NULL;
/* Setting $PERF_CONFIG makes perf read _only_ the given config file. */
if (config_exclusive_filename)
return perf_config_from_file(fn, config_exclusive_filename, data);
if (perf_config_system() && !access(perf_etc_perfconfig(), R_OK)) {
ret += perf_config_from_file(fn, perf_etc_perfconfig(),
data);
found += 1;
}
home = getenv("HOME");
if (perf_config_global() && home) {
char *user_config = strdup(mkpath("%s/.perfconfig", home));
if (!access(user_config, R_OK)) {
ret += perf_config_from_file(fn, user_config, data);
found += 1;
}
free(user_config);
}
repo_config = perf_pathdup("config");
if (!access(repo_config, R_OK)) {
ret += perf_config_from_file(fn, repo_config, data);
found += 1;
}
free(repo_config);
if (found == 0)
return -1;
return ret;
}
/*
* Call this to report error for your variable that should not
* get a boolean value (i.e. "[my] var" means "true").
*/
int config_error_nonbool(const char *var)
{
return error("Missing value for '%s'", var);
}
perf buildid: add perfconfig option to specify buildid cache dir This patch adds the ability to specify an alternate directory to store the buildid cache (buildids, copy of binaries). By default, it is hardcoded to $HOME/.debug. This directory contains immutable data. The layout of the directory is such that no conflicts in filenames are possible. A modification in a file, yields a different buildid and thus a different location in the subdir hierarchy. You may want to put the buildid cache elsewhere because of disk space limitation or simply to share the cache between users. It is also useful for remote collect vs. local analysis of profiles. This patch adds a new config option to the perfconfig file. Under the tag 'buildid', there is a dir option. For instance, if you have: $ cat /etc/perfconfig [buildid] dir = /var/cache/perf-buildid All buildids and binaries are be saved in the directory specified. The perf record, buildid-list, buildid-cache, report, annotate, and archive commands will it to pull information out. The option can be set in the system-wide perfconfig file or in the $HOME/.perfconfig file. Cc: David S. Miller <davem@davemloft.net> Cc: Frédéric Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Cc: Tom Zanussi <tzanussi@gmail.com> LKML-Reference: <4c055fb7.df0ce30a.5f0d.ffffae52@mx.google.com> Signed-off-by: Stephane Eranian <eranian@google.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2010-06-01 19:25:01 +00:00
struct buildid_dir_config {
char *dir;
};
static int buildid_dir_command_config(const char *var, const char *value,
void *data)
{
struct buildid_dir_config *c = data;
const char *v;
/* same dir for all commands */
if (!prefixcmp(var, "buildid.") && !strcmp(var + 8, "dir")) {
v = perf_config_dirname(var, value);
if (!v)
return -1;
strncpy(c->dir, v, MAXPATHLEN-1);
c->dir[MAXPATHLEN-1] = '\0';
}
return 0;
}
static void check_buildid_dir_config(void)
{
struct buildid_dir_config c;
c.dir = buildid_dir;
perf_config(buildid_dir_command_config, &c);
}
void set_buildid_dir(void)
{
buildid_dir[0] = '\0';
/* try config file */
check_buildid_dir_config();
/* default to $HOME/.debug */
if (buildid_dir[0] == '\0') {
char *v = getenv("HOME");
if (v) {
snprintf(buildid_dir, MAXPATHLEN-1, "%s/%s",
v, DEBUG_CACHE_DIR);
} else {
strncpy(buildid_dir, DEBUG_CACHE_DIR, MAXPATHLEN-1);
}
buildid_dir[MAXPATHLEN-1] = '\0';
}
/* for communicating with external commands */
setenv("PERF_BUILDID_DIR", buildid_dir, 1);
}