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tools lib api fs: Introduce sysfs__read_{int,ull}()

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To read either an int or an unsigned long long value from the given
file.

E.g.:

  $ cat /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_max_freq
  3200000
  $ ./sysfs__read_ull
  devices/system/cpu/cpu0/cpufreq/cpuinfo_max_freq
  /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_max_freq=3200000
  $

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-4a12m4d5k8m4qgc1vguocvei@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Arnaldo Carvalho de Melo 2015-09-10 11:58:50 -03:00
parent e0838e029f
commit 2d729f6a8a
2 changed files with 49 additions and 0 deletions
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45
tools/lib/api/fs/fs.c
View File

@ -1,5 +1,6 @@
#include <ctype.h>
#include <errno.h>
#include <limits.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
@ -281,6 +282,50 @@ int filename__read_int(const char *filename, int *value)
return err;
}
int filename__read_ull(const char *filename, unsigned long long *value)
{
char line[64];
int fd = open(filename, O_RDONLY), err = -1;
if (fd < 0)
return -1;
if (read(fd, line, sizeof(line)) > 0) {
*value = strtoull(line, NULL, 10);
if (*value != ULLONG_MAX)
err = 0;
}
close(fd);
return err;
}
int sysfs__read_ull(const char *entry, unsigned long long *value)
{
char path[PATH_MAX];
const char *sysfs = sysfs__mountpoint();
if (!sysfs)
return -1;
snprintf(path, sizeof(path), "%s/%s", sysfs, entry);
return filename__read_ull(path, value);
}
int sysfs__read_int(const char *entry, int *value)
{
char path[PATH_MAX];
const char *sysfs = sysfs__mountpoint();
if (!sysfs)
return -1;
snprintf(path, sizeof(path), "%s/%s", sysfs, entry);
return filename__read_int(path, value);
}
int sysctl__read_int(const char *sysctl, int *value)
{
char path[PATH_MAX];

4
tools/lib/api/fs/fs.h
View File

@ -25,5 +25,9 @@ FS(tracefs)
int filename__read_int(const char *filename, int *value);
int filename__read_ull(const char *filename, unsigned long long *value);
int sysctl__read_int(const char *sysctl, int *value);
int sysfs__read_int(const char *entry, int *value);
int sysfs__read_ull(const char *entry, unsigned long long *value);
#endif /* __API_FS__ */