[PATCH 2/2] hpfall: accept disk device to unload as argument

From: Frans Pop
Date: Sat Jul 25 2009 - 15:00:25 EST


Allows users who use an IDE driver for their disk to use hpfall without
having to modify the source. By default /dev/sda is used.
Suggested by Christian Thaeter in http://lkml.org/lkml/2009/3/25/505.

While we're add it, improve error message if opening /dev/freefall fails.

Signed-off-by: Frans Pop <elendil@xxxxxxxxx>
Cc: Pavel Machek <pavel@xxxxxx>
Cc: Christian Thaeter <ct@xxxxxxxxxx>

diff --git a/Documentation/hwmon/hpfall.c b/Documentation/hwmon/hpfall.c
index a3cfe1a..681ec22 100644
--- a/Documentation/hwmon/hpfall.c
+++ b/Documentation/hwmon/hpfall.c
@@ -19,6 +19,32 @@
#include <sys/mman.h>
#include <sched.h>

+char unload_heads_path[64];
+
+int set_unload_heads_path(char *device)
+{
+ char devname[64];
+
+ if (strlen(device) <= 5 || strncmp(device, "/dev/", 5) != 0)
+ return -EINVAL;
+ strncpy(devname, device + 5, sizeof(devname));
+
+ snprintf(unload_heads_path, sizeof(unload_heads_path),
+ "/sys/block/%s/device/unload_heads", devname);
+ return 0;
+}
+int valid_disk(void)
+{
+ int fd = open(unload_heads_path, O_RDONLY);
+ if (fd < 0) {
+ perror(unload_heads_path);
+ return 0;
+ }
+
+ close(fd);
+ return 1;
+}
+
void write_int(char *path, int i)
{
char buf[1024];
@@ -42,7 +68,7 @@ void set_led(int on)

void protect(int seconds)
{
- write_int("/sys/block/sda/device/unload_heads", seconds*1000);
+ write_int(unload_heads_path, seconds*1000);
}

int on_ac(void)
@@ -61,14 +87,27 @@ void ignore_me(void)
set_led(0);
}

-int main(int argc, char *argv[])
+int main(int argc, char **argv)
{
int fd, ret;
struct sched_param param;

+ if (argc == 1)
+ ret = set_unload_heads_path("/dev/sda");
+ else if (argc == 2)
+ ret = set_unload_heads_path(argv[1]);
+ else
+ ret = -EINVAL;
+
+ if (ret || !valid_disk()) {
+ fprintf(stderr, "usage: %s <device> (default: /dev/sda)\n",
+ argv[0]);
+ exit(1);
+ }
+
fd = open("/dev/freefall", O_RDONLY);
if (fd < 0) {
- perror("open");
+ perror("/dev/freefall");
return EXIT_FAILURE;
}

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