[PATCH v2 0/16] x86_energy_perf_policy cleanups

[PATCH v2 0/16] x86_energy_perf_policy cleanups

[Len Brown]

These patches have changed since v1:

[PATCH 01/16] x86_energy_perf_policy: Rewrite Linux/Android MSR path
	This combines the old patch 1 and patch 2, which didn't
	really stand on their own.

	Andy, I took your reviewed-by off of #1
	because it wasn't on the old #2.

[PATCH 03/16] x86_energy_perf_policy: Harden with strtol()
	Updated to address human and AI comments.

[PATCH 07/16] x86_energy_perf_policy: Bound package iteration
[PATCH 08/16] x86_energy_perf_policy: Cleanup: Define
	Andy, These had RB, but resending b/c AI review asked for some tweaks.

[PATCH 09/16] x86_energy_perf_policy: Cleanup: Define BCLK_MHZ
	Updated per Andy comments.

[PATCH 13/16] <I combined the previous trivial #14 & #15 Constify patches>

[PATCH 15/16] x86_energy_perf_policy: Simplify write_sysfs() return
	Re-written due to review comments

[PATCH 01/16] x86_energy_perf_policy: Rewrite Linux/Android MSR path discovery

[Len Brown]

From: Len Brown <len.brown@intel.com>

First check that the Linux MSR driver path exists, modprobe if no.
If still no, then check that the Android MSR driver path exists.

Read or Write permissions are handled at run-time
in the get_msr()/put_msr() error paths.

Create set_msr_path() helper.

Return -1 for all fatal errors.

Suggested-by: Andy Shevchenko <andriy.shevchenko@intel.com>
Assisted-by: GitHub-Copilot:Claude-Sonnet-4.6
Signed-off-by: Len Brown <len.brown@intel.com>
---
 .../x86_energy_perf_policy.c                  | 73 ++++++++++++-------
 1 file changed, 47 insertions(+), 26 deletions(-)

diff --git a/tools/power/x86/x86_energy_perf_policy/x86_energy_perf_policy.c b/tools/power/x86/x86_energy_perf_policy/x86_energy_perf_policy.c
index 0dc959e30076..8a15093a485e 100644
--- a/tools/power/x86/x86_energy_perf_policy/x86_energy_perf_policy.c
+++ b/tools/power/x86/x86_energy_perf_policy/x86_energy_perf_policy.c
@@ -15,6 +15,7 @@
 #include <sys/types.h>
 #include <sched.h>
 #include <sys/stat.h>
+#include <sys/wait.h>
 #include <sys/resource.h>
 #include <getopt.h>
 #include <err.h>
@@ -98,6 +99,7 @@ unsigned char update_platform_profile;
 int soc_slider_balance;
 int soc_slider_offset;
 char platform_profile[64];
+char msr_path[64];
 
 #define PATH_TO_CPU "/sys/devices/system/cpu/"
 #define SYSFS_PATH_MAX 255
@@ -799,21 +801,32 @@ void err_on_hypervisor(void)
 		err(-1, "not supported on this virtual machine");
 }
 
+/*
+ * if (use_android_msr_path)
+ *	msr_path = /dev/msr%d	// Android
+ * else
+ *	msr_path = /dev/cpu/%d/msr	// Linux
+ */
+static void set_msr_path(int cpu)
+{
+	if (snprintf(msr_path, sizeof(msr_path), use_android_msr_path ? "/dev/msr%d" : "/dev/cpu/%d/msr", cpu) >= (int)sizeof(msr_path))
+		err(-1, "MSR path buffer overflow for cpu%d", cpu);
+}
+
 int get_msr(int cpu, int offset, unsigned long long *msr)
 {
 	int retval;
-	char pathname[32];
 	int fd;
 
-	sprintf(pathname, use_android_msr_path ? "/dev/msr%d" : "/dev/cpu/%d/msr", cpu);
-	fd = open(pathname, O_RDONLY);
+	set_msr_path(cpu);
+	fd = open(msr_path, O_RDONLY);
 	if (fd < 0)
-		err(-1, "%s open failed, try chown or chmod +r %s, or run as root", pathname, use_android_msr_path ? "/dev/msr*" : "/dev/cpu/*/msr");
+		err(-1, "%s open failed, try chown or chmod +r, or run as root", msr_path);
 
 	retval = pread(fd, msr, sizeof(*msr), offset);
 	if (retval != sizeof(*msr)) {
 		err_on_hypervisor();
-		err(-1, "%s offset 0x%llx read failed", pathname, (unsigned long long)offset);
+		err(-1, "%s offset 0x%llx read failed", msr_path, (unsigned long long)offset);
 	}
 
 	if (debug > 1)
@@ -825,14 +838,13 @@ int get_msr(int cpu, int offset, unsigned long long *msr)
 
 int put_msr(int cpu, int offset, unsigned long long new_msr)
 {
-	char pathname[32];
 	int retval;
 	int fd;
 
-	sprintf(pathname, use_android_msr_path ? "/dev/msr%d" : "/dev/cpu/%d/msr", cpu);
-	fd = open(pathname, O_RDWR);
+	set_msr_path(cpu);
+	fd = open(msr_path, O_RDWR);
 	if (fd < 0)
-		err(-1, "%s open failed, try chown or chmod +r %s, or run as root", pathname, use_android_msr_path ? "/dev/msr*" : "/dev/cpu/*/msr");
+		err(-1, "%s open failed, try chown or chmod +w, or run as root", msr_path);
 
 	retval = pwrite(fd, &new_msr, sizeof(new_msr), offset);
 	if (retval != sizeof(new_msr))
@@ -1601,32 +1613,41 @@ void set_base_cpu(void)
 		err(-ENODEV, "No valid cpus found");
 }
 
-static void probe_android_msr_path(void)
+/* return 0 if path exists */
+static int check_msr_path(void)
 {
 	struct stat sb;
-	char test_path[32];
 
-	sprintf(test_path, "/dev/msr%d", base_cpu);
-	if (stat(test_path, &sb) == 0)
-		use_android_msr_path = 1;
+	return stat(msr_path, &sb);
 }
 
+/*
+ * Check Linux MSR path
+ * If it fails, try modprobe and check it again
+ * If still no joy, enable Android path and try again
+ */
 void probe_dev_msr(void)
 {
-	struct stat sb;
-	char pathname[32];
+	int retval;
 
-	probe_android_msr_path();
+	use_android_msr_path = 0;
+	set_msr_path(base_cpu);
+	if (check_msr_path() == 0)
+		return;
 
-	sprintf(pathname, use_android_msr_path ? "/dev/msr%d" : "/dev/cpu/%d/msr", base_cpu);
-	if (stat(pathname, &sb)) {
-		if (system("/sbin/modprobe msr > /dev/null 2>&1")) {
-			if (use_android_msr_path)
-				err(-5, "no /dev/msr0, Try \"# modprobe msr\" ");
-			else
-				err(-5, "no /dev/cpu/0/msr, Try \"# modprobe msr\" ");
-		}
-	}
+	retval = system("/sbin/modprobe msr > /dev/null 2>&1");
+
+	if (check_msr_path() == 0)
+		return;
+
+	use_android_msr_path = 1;
+	set_msr_path(base_cpu);
+	if (check_msr_path() == 0)
+		return;
+
+	if (WIFEXITED(retval))
+		retval = WEXITSTATUS(retval);
+	errx(-1, "\"msr\" driver support required, modprobe msr returned %d", retval);
 }
 
 static void get_cpuid_or_exit(unsigned int leaf, unsigned int *eax, unsigned int *ebx, unsigned int *ecx, unsigned int *edx)
-- 
2.45.2

[PATCH 03/16] x86_energy_perf_policy: Harden with strtol()

[Len Brown]

From: Len Brown <len.brown@intel.com>

Replace atoi() with strtol() and proper error checking when parsing the
--hwp-use-pkg command-line argument value, and other spots.

Add explicit check that value is in valid range [0, 1].

Update associated error message strings.

parse_optarg_string() now returns long, as returned from strtol().

Assisted-by: GitHub-Copilot:Claude-Sonnet-4.6
Signed-off-by: Len Brown <len.brown@intel.com>
---
 .../x86_energy_perf_policy.c                  | 71 ++++++++++---------
 1 file changed, 39 insertions(+), 32 deletions(-)

diff --git a/tools/power/x86/x86_energy_perf_policy/x86_energy_perf_policy.c b/tools/power/x86/x86_energy_perf_policy/x86_energy_perf_policy.c
index da89b267f357..d53427a059f3 100644
--- a/tools/power/x86/x86_energy_perf_policy/x86_energy_perf_policy.c
+++ b/tools/power/x86/x86_energy_perf_policy/x86_energy_perf_policy.c
@@ -191,7 +191,7 @@ int parse_cmdline_epb(int i)
 		return ENERGY_PERF_BIAS_PERFORMANCE;
 	}
 	if (i < 0 || i > ENERGY_PERF_BIAS_POWERSAVE)
-		errx(1, "--epb must be from 0 to 15");
+		errx(1, "--epb must be 0 through 15");
 	return i;
 }
 
@@ -305,8 +305,8 @@ int parse_cmdline_hwp_epp(int i)
 	case OPTARG_PERFORMANCE:
 		return HWP_EPP_PERFORMANCE;
 	}
-	if (i < 0 || i > 0xff) {
-		fprintf(stderr, "--hwp-epp must be from 0 to 0xff\n");
+	if (i < 0 || i > 255) {
+		fprintf(stderr, "--hwp-epp must be 0 through 255\n");
 		usage();
 	}
 	return i;
@@ -332,9 +332,9 @@ int parse_cmdline_turbo(int i)
 	return i;
 }
 
-int parse_optarg_string(char *s)
+long parse_optarg_string(char *s)
 {
-	int i;
+	long i;
 	char *endptr;
 
 	if (!strncmp(s, "default", 7))
@@ -355,19 +355,13 @@ int parse_optarg_string(char *s)
 	if (!strncmp(s, "performance", 11))
 		return OPTARG_PERFORMANCE;
 
+	errno = 0;
 	i = strtol(s, &endptr, 0);
-	if (s == endptr) {
-		fprintf(stderr, "no digits in \"%s\"\n", s);
+	if (endptr == s || errno == ERANGE || i < 0 || i > 255) {
+		warnx("bad value \"%s\"", s);
 		usage();
 	}
-	if (i == LONG_MIN || i == LONG_MAX)
-		errx(-1, "%s", s);
 
-	if (i > 0xFF)
-		errx(-1, "%d (0x%x) must be < 256", i, i);
-
-	if (i < 0)
-		errx(-1, "%d (0x%x) must be >= 0", i, i);
 	return i;
 }
 
@@ -424,9 +418,10 @@ void parse_cmdline_cpu(char *s)
 			int end_cpu;
 
 			startp++;
+			errno = 0;
 			end_cpu = strtol(startp, &endp, 10);
-			if (startp == endp)
-				continue;
+			if (startp == endp || errno == ERANGE)
+				errx(1, "Confused by end_cpu '%s'", startp);
 
 			while (cpu <= end_cpu) {
 				if (cpu > max_cpu_num)
@@ -469,11 +464,11 @@ void parse_cmdline_cpu(char *s)
 				break;
 		}
 
+		errno = 0;
 		cpu = strtol(startp, &endp, 10);
-		if (startp == endp)
+		if (startp == endp || errno == ERANGE || cpu < 0 || cpu > max_cpu_num)
 			errx(1, "--cpu cpu-set: confused by '%s'", startp);
-		if (cpu > max_cpu_num)
-			errx(1, "Requested cpu%d exceeds max cpu%d", cpu, max_cpu_num);
+
 		CPU_SET_S(cpu, cpu_setsize, cpu_selected_set);
 		startp = endp;
 	}
@@ -504,9 +499,10 @@ void parse_cmdline_pkg(char *s)
 			int end_pkg;
 
 			startp++;
+			errno = 0;
 			end_pkg = strtol(startp, &endp, 10);
-			if (startp == endp)
-				continue;
+			if (startp == endp || errno == ERANGE)
+				errx(1, "Confused by end_pkg '%s'", startp);
 
 			while (pkg <= end_pkg) {
 				if (pkg > max_pkg_num)
@@ -523,9 +519,11 @@ void parse_cmdline_pkg(char *s)
 			return;
 		}
 
+		errno = 0;
 		pkg = strtol(startp, &endp, 10);
-		if (pkg > max_pkg_num)
-			errx(1, "Requested pkg%d Exceeds max pkg%d", pkg, max_pkg_num);
+		if (startp == endp || errno == ERANGE || pkg < 0 || pkg > max_pkg_num)
+			errx(1, "Confused by pkg '%s'", startp);
+
 		pkg_selected_set |= 1 << pkg;
 		startp = endp;
 	}
@@ -546,6 +544,7 @@ static int parse_cmdline_int(const char *s, int *out)
 	char *endp;
 	long val;
 
+	errno = 0;
 	val = strtol(s, &endp, 0);
 	if (endp == s || errno == ERANGE)
 		return -1;
@@ -714,13 +713,19 @@ void cmdline(int argc, char **argv)
 		case 't':
 			turbo_update_value = parse_cmdline_turbo(parse_optarg_string(optarg));
 			break;
-		case 'u':
-			update_hwp_use_pkg++;
-			if (atoi(optarg) == 0)
-				req_update.hwp_use_pkg = 0;
-			else
-				req_update.hwp_use_pkg = 1;
-			break;
+		case 'u': {
+				char *endp;
+				long val;
+
+				update_hwp_use_pkg++;
+
+				errno = 0;
+				val = strtol(optarg, &endp, 10);
+				if (endp == optarg || errno == ERANGE || val < 0 || val > 1)
+					errx(1, "--hwp-use-pkg: must be 0 or 1");
+				req_update.hwp_use_pkg = val;
+				break;
+			}
 		case 'v':
 			print_version();
 			exit(0);
@@ -1016,8 +1021,9 @@ static int get_epb_sysfs(int cpu)
 	if (!read_sysfs(path, linebuf, 3))
 		return -1;
 
+	errno = 0;
 	val = strtol(linebuf, &endp, 0);
-	if (endp == linebuf || errno == ERANGE)
+	if (endp == linebuf || errno == ERANGE || val < 0 || val > 15)
 		return -1;
 
 	return (int)val;
@@ -1040,8 +1046,9 @@ static int set_epb_sysfs(int cpu, int val)
 	if (ret <= 0)
 		return -1;
 
+	errno = 0;
 	val = strtol(linebuf, &endp, 0);
-	if (endp == linebuf || errno == ERANGE)
+	if (endp == linebuf || errno == ERANGE || val < 0 || val > 15)
 		return -1;
 
 	return (int)val;
-- 
2.45.2

[PATCH 07/16] x86_energy_perf_policy: Bound package iteration

[Len Brown]

From: Len Brown <len.brown@intel.com>

Add explicit bounds checking against MAX_PACKAGES in for_packages()
to prevent potential out-of-bounds bit shift operations.
Also, use consistent shift idiom: (1ULL << pkg_num)

Assisted-by: GitHub-Copilot:Claude-Sonnet-4.6
Reviewed-by: Andy Shevchenko <andriy.shevchenko@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
---
 .../x86/x86_energy_perf_policy/x86_energy_perf_policy.c   | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/tools/power/x86/x86_energy_perf_policy/x86_energy_perf_policy.c b/tools/power/x86/x86_energy_perf_policy/x86_energy_perf_policy.c
index e79462f93f3a..2d77f465f1ee 100644
--- a/tools/power/x86/x86_energy_perf_policy/x86_energy_perf_policy.c
+++ b/tools/power/x86/x86_energy_perf_policy/x86_energy_perf_policy.c
@@ -509,7 +509,7 @@ void parse_cmdline_pkg(char *s)
 			while (pkg <= end_pkg) {
 				if (pkg > max_pkg_num)
 					errx(1, "Requested pkg%d exceeds max pkg%d", pkg, max_pkg_num);
-				pkg_selected_set |= 1 << pkg;
+				pkg_selected_set |= 1ULL << pkg;
 				pkg++;
 			}
 			startp = endp;
@@ -526,7 +526,7 @@ void parse_cmdline_pkg(char *s)
 		if (startp == endp || errno == ERANGE || pkg < 0 || pkg > max_pkg_num)
 			errx(1, "Confused by pkg '%s'", startp);
 
-		pkg_selected_set |= 1 << pkg;
+		pkg_selected_set |= 1ULL << pkg;
 		startp = endp;
 	}
 }
@@ -535,8 +535,8 @@ void for_packages(unsigned long long pkg_set, int (func) (int))
 {
 	int pkg_num;
 
-	for (pkg_num = 0; pkg_num <= max_pkg_num; ++pkg_num) {
-		if (pkg_set & (1UL << pkg_num))
+	for (pkg_num = 0; pkg_num <= max_pkg_num && pkg_num < MAX_PACKAGES; ++pkg_num) {
+		if (pkg_set & (1ULL << pkg_num))
 			func(pkg_num);
 	}
 }
-- 
2.45.2

[PATCH 08/16] x86_energy_perf_policy: Cleanup: Define HWP_WINDOW_MAX_USEC

[Len Brown]

From: Len Brown <len.brown@intel.com>

Define HWP_WINDOW_MAX_USEC
Doing so pointed out that it should be unsigned,
so change associated code that touches it to use unsigned.

Assisted-by: GitHub-Copilot:Claude-Sonnet-4.6
Reviewed-by: Andy Shevchenko <andriy.shevchenko@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
---
 .../x86_energy_perf_policy/x86_energy_perf_policy.c | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/tools/power/x86/x86_energy_perf_policy/x86_energy_perf_policy.c b/tools/power/x86/x86_energy_perf_policy/x86_energy_perf_policy.c
index 2d77f465f1ee..5fb6b0883e55 100644
--- a/tools/power/x86/x86_energy_perf_policy/x86_energy_perf_policy.c
+++ b/tools/power/x86/x86_energy_perf_policy/x86_energy_perf_policy.c
@@ -34,6 +34,9 @@
 #define	OPTARG_BALANCE_PERFORMANCE	(INT_MAX - 4)
 #define	OPTARG_PERFORMANCE		(INT_MAX - 5)
 
+/* Maximum HWP activity window duration in microseconds */
+#define HWP_WINDOW_MAX_USEC 1270000000U
+
 struct msr_hwp_cap {
 	unsigned char highest;
 	unsigned char guaranteed;
@@ -259,7 +262,7 @@ int parse_cmdline_hwp_desired(int i)
 	return i;
 }
 
-int parse_cmdline_hwp_window(int i)
+unsigned int parse_cmdline_hwp_window(unsigned int i)
 {
 	unsigned int exponent;
 
@@ -273,13 +276,13 @@ int parse_cmdline_hwp_window(int i)
 	case OPTARG_PERFORMANCE:
 		return 0;
 	}
-	if (i < 0 || i > 1270000000) {
-		fprintf(stderr, "--hwp-window: 0 for auto; 1 - 1270000000 usec for window duration\n");
+	if (i > HWP_WINDOW_MAX_USEC) {
+		fprintf(stderr, "--hwp-window: 0 for auto; 1 - %u usec for window duration\n", HWP_WINDOW_MAX_USEC);
 		usage();
 	}
 	for (exponent = 0;; ++exponent) {
 		if (debug)
-			printf("%d 10^%d\n", i, exponent);
+			printf("%u 10^%d\n", i, exponent);
 
 		if (i <= 127)
 			break;
@@ -287,7 +290,7 @@ int parse_cmdline_hwp_window(int i)
 		i = i / 10;
 	}
 	if (debug)
-		fprintf(stderr, "%d*10^%d: 0x%x\n", i, exponent, (exponent << 7) | i);
+		fprintf(stderr, "%u*10^%d: 0x%x\n", i, exponent, (exponent << 7) | i);
 
 	return (exponent << 7) | i;
 }
-- 
2.45.2

[PATCH 09/16] x86_energy_perf_policy: Cleanup: Define BCLK_MHZ

[Len Brown]

From: Len Brown <len.brown@intel.com>

Replace the hardcoded value 100 with a named symbolic constant BCLK_MHZ in
ratio_2_sysfs_khz() to document the assumed bus clock frequency.

Assisted-by: GitHub-Copilot:Claude-Sonnet-4.6
Signed-off-by: Len Brown <len.brown@intel.com>
---
 .../x86/x86_energy_perf_policy/x86_energy_perf_policy.c     | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/tools/power/x86/x86_energy_perf_policy/x86_energy_perf_policy.c b/tools/power/x86/x86_energy_perf_policy/x86_energy_perf_policy.c
index 5fb6b0883e55..0a67b6f5381c 100644
--- a/tools/power/x86/x86_energy_perf_policy/x86_energy_perf_policy.c
+++ b/tools/power/x86/x86_energy_perf_policy/x86_energy_perf_policy.c
@@ -37,6 +37,10 @@
 /* Maximum HWP activity window duration in microseconds */
 #define HWP_WINDOW_MAX_USEC 1270000000U
 
+/* Nominal bus clock frequency in MHz - assumed for all HWP systems */
+#define BCLK_MHZ 100
+#define KHZ_PER_MHZ 1000
+
 struct msr_hwp_cap {
 	unsigned char highest;
 	unsigned char guaranteed;
@@ -1163,7 +1167,7 @@ int print_pkg_msrs(int pkg)
  */
 int ratio_2_sysfs_khz(int ratio)
 {
-	int bclk_khz = 100 * 1000;	/* 100,000 KHz = 100 MHz */
+	int bclk_khz = BCLK_MHZ * KHZ_PER_MHZ; /* Convert MHz to KHz */
 
 	return ratio * bclk_khz;
 }
-- 
2.45.2

[PATCH 15/16] x86_energy_perf_policy: Simplify write_sysfs() return type

[Len Brown]

From: Len Brown <len.brown@intel.com>

Simplify error check in write_sysfs().

Suggested-by: Amarjeet <amarjeet@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
---
 .../x86_energy_perf_policy/x86_energy_perf_policy.c  | 12 +++++-------
 1 file changed, 5 insertions(+), 7 deletions(-)

diff --git a/tools/power/x86/x86_energy_perf_policy/x86_energy_perf_policy.c b/tools/power/x86/x86_energy_perf_policy/x86_energy_perf_policy.c
index 904ab803f5c7..2b4d48b520f2 100644
--- a/tools/power/x86/x86_energy_perf_policy/x86_energy_perf_policy.c
+++ b/tools/power/x86/x86_energy_perf_policy/x86_energy_perf_policy.c
@@ -900,14 +900,14 @@ static unsigned int read_sysfs(const char *path, char *buf, size_t buflen)
 	return (unsigned int)numread;
 }
 
-static unsigned int write_sysfs(const char *path, char *buf, size_t buflen)
+static int write_sysfs(const char *path, char *buf, size_t buflen)
 {
 	ssize_t numwritten;
 	int fd;
 
 	fd = open(path, O_WRONLY);
 	if (fd == -1)
-		return 0;
+		return -1;
 
 	numwritten = write(fd, buf, buflen - 1);
 	if (numwritten < 1) {
@@ -919,7 +919,7 @@ static unsigned int write_sysfs(const char *path, char *buf, size_t buflen)
 
 	close(fd);
 
-	return (unsigned int)numwritten;
+	return 0;
 }
 
 static int sysfs_read_string(const char *path, char *buf, size_t buflen)
@@ -944,7 +944,7 @@ static int sysfs_write_string(const char *path, const char *buf)
 	len = snprintf(tmp, sizeof(tmp), "%s\n", buf);
 	if (len < 0 || len >= (int)sizeof(tmp))
 		return -1;
-	return write_sysfs(path, tmp, (size_t)len + 1) ? 0 : -1;
+	return write_sysfs(path, tmp, (size_t)len + 1);
 }
 
 void print_hwp_cap(int cpu, struct msr_hwp_cap *cap, char *str)
@@ -1050,7 +1050,6 @@ static int set_epb_sysfs(int cpu, int val)
 	char path[SYSFS_PATH_MAX];
 	char linebuf[3];
 	char *endp;
-	int ret;
 
 	if (!has_epb)
 		return -1;
@@ -1058,8 +1057,7 @@ static int set_epb_sysfs(int cpu, int val)
 	snprintf(path, sizeof(path), PATH_TO_CPU "cpu%u/power/energy_perf_bias", cpu);
 	snprintf(linebuf, sizeof(linebuf), "%d", val);
 
-	ret = write_sysfs(path, linebuf, 3);
-	if (ret <= 0)
+	if (write_sysfs(path, linebuf, 3))
 		return -1;
 
 	errno = 0;
-- 
2.45.2