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authorLen Brown <len.brown@intel.com>2014-08-15 00:36:50 -0400
committerLen Brown <len.brown@intel.com>2015-02-09 16:41:16 -0500
commit98481e79b60a50d699b79292ff1b7e56e7fa8425 (patch)
tree148ec049930bed66b08ccbfa1dcddc11ebd841c4 /tools
parentbfa76d49576599a4b9f9b7a71f23d73d6dcff735 (diff)
tools/power turbostat: relax dependency on root permission
For turbostat to run as non-root, it needs to permissions: 1. read access to /dev/cpu/*/msr via standard user/group/world file permissions 2. CAP_SYS_RAWIO eg. # setcap cap_sys_rawio=ep turbostat Yes, running as root still works. Signed-off-by: Len Brown <len.brown@intel.com>
Diffstat (limited to 'tools')
-rw-r--r--tools/power/x86/turbostat/turbostat.c53
1 files changed, 41 insertions, 12 deletions
diff --git a/tools/power/x86/turbostat/turbostat.c b/tools/power/x86/turbostat/turbostat.c
index 5b1b807265a1..6f29fc11fde6 100644
--- a/tools/power/x86/turbostat/turbostat.c
+++ b/tools/power/x86/turbostat/turbostat.c
@@ -38,6 +38,8 @@
#include <ctype.h>
#include <sched.h>
#include <cpuid.h>
+#include <linux/capability.h>
+#include <errno.h>
char *proc_stat = "/proc/stat";
unsigned int interval_sec = 5; /* set with -i interval_sec */
@@ -251,15 +253,13 @@ int get_msr(int cpu, off_t offset, unsigned long long *msr)
sprintf(pathname, "/dev/cpu/%d/msr", cpu);
fd = open(pathname, O_RDONLY);
if (fd < 0)
- return -1;
+ err(-1, "%s open failed, try chown or chmod +r /dev/cpu/*/msr, or run as root", pathname);
retval = pread(fd, msr, sizeof *msr, offset);
close(fd);
- if (retval != sizeof *msr) {
- fprintf(stderr, "%s offset 0x%llx read failed\n", pathname, (unsigned long long)offset);
- return -1;
- }
+ if (retval != sizeof *msr)
+ err(-1, "%s offset 0x%llx read failed", pathname, (unsigned long long)offset);
return 0;
}
@@ -1462,10 +1462,40 @@ void check_dev_msr()
"Try \"# modprobe msr\"");
}
-void check_super_user()
+void check_permissions()
{
- if (getuid() != 0)
- errx(-6, "must be root");
+ struct __user_cap_header_struct cap_header_data;
+ cap_user_header_t cap_header = &cap_header_data;
+ struct __user_cap_data_struct cap_data_data;
+ cap_user_data_t cap_data = &cap_data_data;
+ extern int capget(cap_user_header_t hdrp, cap_user_data_t datap);
+ int do_exit = 0;
+
+ /* check for CAP_SYS_RAWIO */
+ cap_header->pid = getpid();
+ cap_header->version = _LINUX_CAPABILITY_VERSION;
+ if (capget(cap_header, cap_data) < 0)
+ err(-6, "capget(2) failed");
+
+ if ((cap_data->effective & (1 << CAP_SYS_RAWIO)) == 0) {
+ do_exit++;
+ warnx("capget(CAP_SYS_RAWIO) failed,"
+ " try \"# setcap cap_sys_rawio=ep %s\"", progname);
+ }
+
+ /* test file permissions */
+ if (euidaccess("/dev/cpu/0/msr", R_OK)) {
+ do_exit++;
+ warn("/dev/cpu/0/msr open failed, try chown or chmod +r /dev/cpu/*/msr");
+ }
+
+ /* if all else fails, thell them to be root */
+ if (do_exit)
+ if (getuid() != 0)
+ warnx("Or simply run as root");
+
+ if (do_exit)
+ exit(-6);
}
int has_nehalem_turbo_ratio_limit(unsigned int family, unsigned int model)
@@ -2299,10 +2329,9 @@ void setup_all_buffers(void)
void turbostat_init()
{
- check_cpuid();
-
check_dev_msr();
- check_super_user();
+ check_permissions();
+ check_cpuid();
setup_all_buffers();
@@ -2441,7 +2470,7 @@ int main(int argc, char **argv)
cmdline(argc, argv);
if (verbose)
- fprintf(stderr, "turbostat v3.7 Feb 6, 2014"
+ fprintf(stderr, "turbostat v3.8 14-Aug 2014"
" - Len Brown <lenb@kernel.org>\n");
turbostat_init();