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Add actledPi.c

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New program acteldPi added. Blinks the ACT led on all mass storage I/O, i.e. not only the SD card.
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Ragnar Jensen 2016-10-02 15:19:30 +02:00 committed by GitHub
parent 4515a6948e
commit cea22cb0b8
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/*
* This is free and unencumbered software released into the public domain.
*
* Anyone is free to copy, modify, publish, use, compile, sell, or
* distribute this software, either in source code form or as a compiled
* binary, for any purpose, commercial or non-commercial, and by any
* means.
*
* In jurisdictions that recognize copyright laws, the author or authors
* of this software dedicate any and all copyright interest in the
* software to the public domain. We make this dedication for the benefit
* of the public at large and to the detriment of our heirs and
* successors. We intend this dedication to be an overt act of
* relinquishment in perpetuity of all present and future rights to this
* software under copyright law.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
* IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR
* OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
* ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
* OTHER DEALINGS IN THE SOFTWARE.
*
* For more information, please refer to <http://unlicense.org/>
*
**************************************************************************
*
* A disk activity light for the Raspberry Pi.
* Blinks the ACT led on all mass storage I/O, i.e. not only the SD card.
* Based on hddled.c - http://members.optusnet.com.au/foonly/whirlpool/code/hddled.c -
*
*
* To compile:
* gcc -Wall -O3 -o actledPi actledPi.c
*
* Options:
* -d, --detach Detach from terminal (become a daemon)
* -r, --refresh=VALUE Refresh interval (default: 20 ms)
*
*/
#define VMSTAT "/proc/vmstat"
#define ACTLED "/sys/class/leds/led0/brightness"
#define TRGCTL "/sys/class/leds/led0/trigger"
#define LOW 0
#define HIGH 1
#define _GNU_SOURCE
#include <argp.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <unistd.h>
static unsigned int o_refresh = 20; /* milliseconds */
static int o_detach = 0;
static volatile sig_atomic_t running = 1;
static char *line = NULL;
static size_t len = 0;
FILE *actled = NULL;
FILE *trigger_ctl = NULL;
/* Reread the vmstat file */
int activity(FILE *vmstat) {
static unsigned int prev_pgpgin, prev_pgpgout;
unsigned int pgpgin, pgpgout;
int found_pgpgin, found_pgpgout;
int result;
/* Reload the vmstat file */
result = TEMP_FAILURE_RETRY(fseek(vmstat, 0L, SEEK_SET));
if (result) {
perror("Could not rewind " VMSTAT);
return result;
}
/* Clear glibc's buffer */
result = TEMP_FAILURE_RETRY(fflush(vmstat));
if (result) {
perror("Could not flush input stream");
return result;
}
/* Extract the I/O stats */
found_pgpgin = found_pgpgout = 0;
while (getline(&line, &len, vmstat) != -1 && errno != EINTR) {
if (sscanf(line, "pgpgin %u", &pgpgin))
found_pgpgin++;
else if (sscanf(line, "pgpgout %u", &pgpgout))
found_pgpgout++;
if (found_pgpgin && found_pgpgout)
break;
}
if (!found_pgpgin || !found_pgpgout) {
fprintf(stderr, "Could not find required lines in " VMSTAT);
return -1;
}
/* Anything changed? */
result =
(prev_pgpgin != pgpgin) ||
(prev_pgpgout != pgpgout);
prev_pgpgin = pgpgin;
prev_pgpgout = pgpgout;
return result;
}
/* Update the LED */
void led(int on) {
static int current = 1; /* Ensure the LED turns off on first call */
if (current == on)
return;
if (on) {
fputs("255\n", actled);
} else {
fputs("0\n", actled);
}
fflush(actled);
current = on;
}
/* Signal handler -- break out of the main loop */
void shutdown(int sig) {
running = 0;
}
/* Argp parser function */
error_t parse_options(int key, char *arg, struct argp_state *state) {
switch (key) {
case 'd':
o_detach = 1;
break;
case 'r':
o_refresh = strtol(arg, NULL, 10);
if (o_refresh < 10)
argp_failure(state, EXIT_FAILURE, 0,
"refresh interval must be at least 10");
break;
}
return 0;
}
int main(int argc, char **argv) {
struct argp_option options[] = {
{ "detach", 'd', NULL, 0, "Detach from terminal" },
{ "refresh", 'r', "VALUE", 0, "Refresh interval (default: 20 ms)" },
{ 0 },
};
struct argp parser = {
NULL, parse_options, NULL,
"Show disk activity on all disks.",
NULL, NULL, NULL
};
int status = EXIT_FAILURE;
FILE *vmstat = NULL;
struct timespec delay;
/* Parse the command-line */
parser.options = options;
if (argp_parse(&parser, argc, argv, ARGP_NO_ARGS, NULL, NULL))
goto out;
delay.tv_sec = o_refresh / 1000;
delay.tv_nsec = 1000000 * (o_refresh % 1000);
/* Open the vmstat file */
vmstat = fopen(VMSTAT, "r");
if (!vmstat) {
perror("Could not open " VMSTAT " for reading");
goto out;
}
/* Change the trigger on the OK/Act LED to "none" */
trigger_ctl = fopen(TRGCTL, "rw");
if (!trigger_ctl) {
perror("Unable to change LED trigger");
goto out;
}
fputs ("none\n", trigger_ctl);
fclose (trigger_ctl);
/* Open the actled file */
actled = fopen(ACTLED, "w");
if (!actled) {
perror("Could not open " ACTLED " for writing");
goto out;
}
/* Ensure the LED is off */
led(LOW);
if (activity(vmstat) < 0)
goto out;
/* Detach from terminal? */
if (o_detach) {
pid_t child = fork();
if (child < 0) {
perror("Could not detach from terminal");
goto out;
}
if (child) {
/* I am the parent */
status = EXIT_SUCCESS;
goto out;
}
}
/* We catch these signals so we can clean up */
{
struct sigaction action;
memset(&action, 0, sizeof(action));
action.sa_handler = shutdown;
sigemptyset(&action.sa_mask);
action.sa_flags = 0; /* We block on usleep; don't use SA_RESTART */
sigaction(SIGHUP, &action, NULL);
sigaction(SIGINT, &action, NULL);
sigaction(SIGTERM, &action, NULL);
}
/* Loop until signal received */
while (running) {
int a;
if (nanosleep(&delay, NULL) < 0)
break;
a = activity(vmstat);
if (a < 0)
break;
led(a);
}
/* Ensure the LED is off */
led(LOW);
status = EXIT_SUCCESS;
out:
if (line) free(line);
if (vmstat) fclose(vmstat);
if (actled) {
fclose(actled);
trigger_ctl = fopen(TRGCTL, "rw");
fputs("mmc0\n", trigger_ctl);
fclose(trigger_ctl);
}
return status;
}