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tools: add gpionotify

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Add a gpionotify tool, based on gpiomon, to report line info change
events read from chip file descriptors.

Inspired by the gpio-watch tool in the linux kernel, but with gpiomon
features such as custom formatted output, filtering events of
interest and exiting after a number of events, so more useful for
scripting.

Default output is minimalist, so just time, event type and line id.
Full event details are available using the custom formatted output.

Signed-off-by: Kent Gibson <warthog618@gmail.com>
[Bartosz: coding style tweaks]
Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>
This commit is contained in:
Kent Gibson
2022-11-21 18:22:51 +08:00
committed by Bartosz Golaszewski
parent 8ffb648928
commit 5f194b001a
4 changed files with 454 additions and 2 deletions
Download Patch File Download Diff File Expand all files Collapse all files

2
man/Makefile.am
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@@ -3,7 +3,7 @@
if WITH_MANPAGES
dist_man1_MANS = gpiodetect.man gpioinfo.man gpioget.man gpioset.man gpiomon.man
dist_man1_MANS = gpiodetect.man gpioinfo.man gpioget.man gpioset.man gpiomon.man gpionotify.man
%.man: $(top_builddir)/tools/$(*F)
help2man $(top_builddir)/tools/$(*F) --include=$(srcdir)/template --output=$(builddir)/$@ --no-info

1
tools/.gitignore vendored
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@@ -6,3 +6,4 @@ gpioinfo
gpioget
gpioset
gpiomon
gpionotify

4
tools/Makefile.am
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@@ -16,7 +16,7 @@ LDADD += $(LIBEDIT_LIBS)
endif
bin_PROGRAMS = gpiodetect gpioinfo gpioget gpioset gpiomon
bin_PROGRAMS = gpiodetect gpioinfo gpioget gpioset gpiomon gpionotify
gpiodetect_SOURCES = gpiodetect.c
@@ -28,6 +28,8 @@ gpioset_SOURCES = gpioset.c
gpiomon_SOURCES = gpiomon.c
gpionotify_SOURCES = gpionotify.c
EXTRA_DIST = gpio-tools-test gpio-tools-test.bats
if WITH_TESTS

449
tools/gpionotify.c Normal file
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@@ -0,0 +1,449 @@
// SPDX-License-Identifier: GPL-2.0-or-later
// SPDX-FileCopyrightText: 2022 Kent Gibson <warthog618@gmail.com>
#include <getopt.h>
#include <gpiod.h>
#include <inttypes.h>
#include <poll.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include "tools-common.h"
struct config {
bool banner;
bool by_name;
bool quiet;
bool strict;
bool unquoted;
int event_type;
int events_wanted;
const char *chip_id;
const char *fmt;
int timestamp_fmt;
};
static void print_help(void)
{
printf("Usage: %s [OPTIONS] <line>...\n", get_progname());
printf("\n");
printf("Wait for changes to info on GPIO lines and print them to standard output.\n");
printf("\n");
printf("Lines are specified by name, or optionally by offset if the chip option\n");
printf("is provided.\n");
printf("\n");
printf("Options:\n");
printf(" --banner\t\tdisplay a banner on successful startup\n");
printf(" --by-name\t\ttreat lines as names even if they would parse as an offset\n");
printf(" -c, --chip <chip>\trestrict scope to a particular chip\n");
printf(" -e, --event <event>\tspecify the events to monitor\n");
printf("\t\t\tPossible values: 'requested', 'released', 'reconfigured'.\n");
printf("\t\t\t(default is all events)\n");
printf(" -h, --help\t\tdisplay this help and exit\n");
printf(" -F, --format <fmt>\tspecify a custom output format\n");
printf(" --localtime\tconvert event timestamps to local time\n");
printf(" -n, --num-events <num>\n");
printf("\t\t\texit after processing num events\n");
printf(" -q, --quiet\t\tdon't generate any output\n");
printf(" -s, --strict\t\tabort if requested line names are not unique\n");
printf(" --unquoted\tdon't quote line or consumer names\n");
printf(" --utc\t\tconvert event timestamps to UTC\n");
printf(" -v, --version\t\toutput version information and exit\n");
print_chip_help();
printf("\n");
printf("Format specifiers:\n");
printf(" %%o GPIO line offset\n");
printf(" %%l GPIO line name\n");
printf(" %%c GPIO chip name\n");
printf(" %%e numeric info event type ('1' - requested, '2' - released or '3' - reconfigured)\n");
printf(" %%E info event type ('requested', 'released' or 'reconfigured')\n");
printf(" %%a line attributes\n");
printf(" %%C consumer\n");
printf(" %%S event timestamp as seconds\n");
printf(" %%U event timestamp as UTC\n");
printf(" %%L event timestamp as local time\n");
}
static int parse_event_type_or_die(const char *option)
{
if (strcmp(option, "requested") == 0)
return GPIOD_INFO_EVENT_LINE_REQUESTED;
if (strcmp(option, "released") == 0)
return GPIOD_INFO_EVENT_LINE_RELEASED;
if (strcmp(option, "reconfigured") != 0)
die("invalid edge: %s", option);
return GPIOD_INFO_EVENT_LINE_CONFIG_CHANGED;
}
static int parse_config(int argc, char **argv, struct config *cfg)
{
static const char *const shortopts = "+c:e:hF:n:qshv";
const struct option longopts[] = {
{ "banner", no_argument, NULL, '-'},
{ "by-name", no_argument, NULL, 'B'},
{ "chip", required_argument, NULL, 'c' },
{ "event", required_argument, NULL, 'e' },
{ "format", required_argument, NULL, 'F' },
{ "help", no_argument, NULL, 'h' },
{ "localtime", no_argument, &cfg->timestamp_fmt, 2 },
{ "num-events", required_argument, NULL, 'n' },
{ "quiet", no_argument, NULL, 'q' },
{ "silent", no_argument, NULL, 'q' },
{ "strict", no_argument, NULL, 's' },
{ "unquoted", no_argument, NULL, 'Q' },
{ "utc", no_argument, &cfg->timestamp_fmt, 1 },
{ "version", no_argument, NULL, 'v' },
{ GETOPT_NULL_LONGOPT },
};
int opti, optc;
memset(cfg, 0, sizeof(*cfg));
for (;;) {
optc = getopt_long(argc, argv, shortopts, longopts, &opti);
if (optc < 0)
break;
switch (optc) {
case '-':
cfg->banner = true;
break;
case 'B':
cfg->by_name = true;
break;
case 'c':
cfg->chip_id = optarg;
break;
case 'e':
cfg->event_type = parse_event_type_or_die(optarg);
break;
case 'F':
cfg->fmt = optarg;
break;
case 'n':
cfg->events_wanted = parse_uint_or_die(optarg);
break;
case 'q':
cfg->quiet = true;
break;
case 'Q':
cfg->unquoted = true;
break;
case 's':
cfg->strict = true;
break;
case 'h':
print_help();
exit(EXIT_SUCCESS);
case 'v':
print_version();
exit(EXIT_SUCCESS);
case '?':
die("try %s --help", get_progname());
case 0:
break;
default:
abort();
}
}
return optind;
}
static void print_banner(int num_lines, char **lines)
{
int i;
if (num_lines > 1) {
printf("Watching lines ");
for (i = 0; i < num_lines - 1; i++)
printf("'%s', ", lines[i]);
printf("and '%s'...\n", lines[i]);
} else {
printf("Watching line '%s'...\n", lines[0]);
}
}
static void print_event_type(int evtype)
{
switch (evtype) {
case GPIOD_INFO_EVENT_LINE_REQUESTED:
fputs("requested", stdout);
break;
case GPIOD_INFO_EVENT_LINE_RELEASED:
fputs("released", stdout);
break;
case GPIOD_INFO_EVENT_LINE_CONFIG_CHANGED:
fputs("reconfigured", stdout);
break;
default:
fputs("unknown", stdout);
break;
}
}
/*
* A convenience function to map clock monotonic to realtime, as uAPI only
* supports CLOCK_MONOTONIC.
*
* Samples the realtime clock on either side of a monotonic sample and averages
* the realtime samples to estimate the offset between the two clocks.
* Any time shifts between the two realtime samples will result in the
* monotonic time being mapped to the average of the before and after, so
* half way between the old and new times.
*
* Any CPU suspension between the event being generated and converted will
* result in the returned time being shifted by the period of suspension.
*/
static uint64_t monotonic_to_realtime(uint64_t evtime)
{
uint64_t before, after, mono;
struct timespec ts;
clock_gettime(CLOCK_REALTIME, &ts);
before = ts.tv_nsec + ((uint64_t)ts.tv_sec) * 1000000000;
clock_gettime(CLOCK_MONOTONIC, &ts);
mono = ts.tv_nsec + ((uint64_t)ts.tv_sec) * 1000000000;
clock_gettime(CLOCK_REALTIME, &ts);
after = ts.tv_nsec + ((uint64_t)ts.tv_sec) * 1000000000;
evtime += (after/2 - mono + before/2);
return evtime;
}
static void event_print_formatted(struct gpiod_info_event *event,
struct line_resolver *resolver, int chip_num,
struct config *cfg)
{
const char *lname, *prev, *curr, *consumer;
struct gpiod_line_info *info;
unsigned int offset;
uint64_t evtime;
int evtype;
char fmt;
info = gpiod_info_event_get_line_info(event);
evtime = gpiod_info_event_get_timestamp_ns(event);
evtype = gpiod_info_event_get_event_type(event);
offset = gpiod_line_info_get_offset(info);
for (prev = curr = cfg->fmt;;) {
curr = strchr(curr, '%');
if (!curr) {
fputs(prev, stdout);
break;
}
if (prev != curr)
fwrite(prev, curr - prev, 1, stdout);
fmt = *(curr + 1);
switch (fmt) {
case 'a':
print_line_attributes(info, cfg->unquoted);
break;
case 'c':
fputs(get_chip_name(resolver, chip_num), stdout);
break;
case 'C':
if (!gpiod_line_info_is_used(info)) {
consumer = "unused";
} else {
consumer = gpiod_line_info_get_consumer(info);
if (!consumer)
consumer = "kernel";
}
fputs(consumer, stdout);
break;
case 'e':
printf("%d", evtype);
break;
case 'E':
print_event_type(evtype);
break;
case 'l':
lname = gpiod_line_info_get_name(info);
if (!lname)
lname = "unnamed";
fputs(lname, stdout);
break;
case 'L':
print_event_time(monotonic_to_realtime(evtime), 2);
break;
case 'o':
printf("%u", offset);
break;
case 'S':
print_event_time(evtime, 0);
break;
case 'U':
print_event_time(monotonic_to_realtime(evtime), 1);
break;
case '%':
fputc('%', stdout);
break;
case '\0':
fputc('%', stdout);
goto end;
default:
fwrite(curr, 2, 1, stdout);
break;
}
curr += 2;
prev = curr;
}
end:
fputc('\n', stdout);
}
static void event_print_human_readable(struct gpiod_info_event *event,
struct line_resolver *resolver, int chip_num,
struct config *cfg)
{
struct gpiod_line_info *info;
unsigned int offset;
uint64_t evtime;
char *evname;
int evtype;
info = gpiod_info_event_get_line_info(event);
evtime = gpiod_info_event_get_timestamp_ns(event);
evtype = gpiod_info_event_get_event_type(event);
offset = gpiod_line_info_get_offset(info);
switch (evtype) {
case GPIOD_INFO_EVENT_LINE_REQUESTED:
evname = "requested";
break;
case GPIOD_INFO_EVENT_LINE_RELEASED:
evname = "released";
break;
case GPIOD_INFO_EVENT_LINE_CONFIG_CHANGED:
evname = "reconfigured";
break;
default:
evname = "unknown";
}
if (cfg->timestamp_fmt)
evtime = monotonic_to_realtime(evtime);
print_event_time(evtime, cfg->timestamp_fmt);
printf("\t%s\t", evname);
print_line_id(resolver, chip_num, offset, cfg->chip_id, cfg->unquoted);
fputc('\n', stdout);
}
static void event_print(struct gpiod_info_event *event,
struct line_resolver *resolver, int chip_num,
struct config *cfg)
{
if (cfg->quiet)
return;
if (cfg->fmt)
event_print_formatted(event, resolver, chip_num, cfg);
else
event_print_human_readable(event, resolver, chip_num, cfg);
}
int main(int argc, char **argv)
{
int i, j, events_done = 0, evtype;
struct line_resolver *resolver;
struct gpiod_info_event *event;
struct gpiod_chip **chips;
struct gpiod_chip *chip;
struct pollfd *pollfds;
struct config cfg;
i = parse_config(argc, argv, &cfg);
argc -= optind;
argv += optind;
if (argc < 1)
die("at least one GPIO line must be specified");
if (argc > 64)
die("too many lines given");
resolver = resolve_lines(argc, argv, cfg.chip_id, cfg.strict,
cfg.by_name);
validate_resolution(resolver, cfg.chip_id);
chips = calloc(resolver->num_chips, sizeof(*chips));
pollfds = calloc(resolver->num_chips, sizeof(*pollfds));
if (!pollfds)
die("out of memory");
for (i = 0; i < resolver->num_chips; i++) {
chip = gpiod_chip_open(resolver->chips[i].path);
if (!chip)
die_perror("unable to open chip '%s'",
resolver->chips[i].path);
for (j = 0; j < resolver->num_lines; j++)
if ((resolver->lines[j].chip_num == i) &&
!gpiod_chip_watch_line_info(
chip, resolver->lines[j].offset))
die_perror("unable to watch line on chip '%s'",
resolver->chips[i].path);
chips[i] = chip;
pollfds[i].fd = gpiod_chip_get_fd(chip);
pollfds[i].events = POLLIN;
}
if (cfg.banner)
print_banner(argc, argv);
for (;;) {
fflush(stdout);
if (poll(pollfds, resolver->num_chips, -1) < 0)
die_perror("error polling for events");
for (i = 0; i < resolver->num_chips; i++) {
if (pollfds[i].revents == 0)
continue;
event = gpiod_chip_read_info_event(chips[i]);
if (!event)
die_perror("unable to retrieve chip event");
if (cfg.event_type) {
evtype = gpiod_info_event_get_event_type(event);
if (evtype != cfg.event_type)
continue;
}
event_print(event, resolver, i, &cfg);
events_done++;
if (cfg.events_wanted &&
events_done >= cfg.events_wanted)
goto done;
}
}
done:
for (i = 0; i < resolver->num_chips; i++)
gpiod_chip_close(chips[i]);
free(chips);
free_line_resolver(resolver);
return EXIT_SUCCESS;
}