[PATCH evtest 2/2] Add one-shot query functionality
Peter Hutterer
peter.hutterer at who-t.net
Sun Jul 17 17:29:58 PDT 2011
On Sat, Jul 16, 2011 at 11:07:14PM +0100, Daniel Drake wrote:
> Add functionality to query evdev state of a specific key, switch, button,
> LED or sound event. This is useful in programs such as powerd
> (http://wiki.laptop.org/go/Powerd) which need to query things like the
> state of the laptop lid switch from shell code.
>
> Original capture-mode functionality is left unchanged and is still
> activated by default. New usage modes are explained in the man page.
>
> Signed-off-by: Daniel Drake <dsd at laptop.org>
Thanks, looking better and much easier to review. I've merged patch 1 again,
for this one see the comments below (and Walter's comments in the other
email).
> ---
> evtest.c | 203 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++--
> evtest.txt | 33 ++++++++--
> 2 files changed, 226 insertions(+), 10 deletions(-)
>
> diff --git a/evtest.c b/evtest.c
> index eb04a51..9a7ac7f 100644
> --- a/evtest.c
> +++ b/evtest.c
> @@ -49,6 +49,8 @@
> #include <stdlib.h>
> #include <dirent.h>
> #include <errno.h>
> +#include <getopt.h>
> +#include <ctype.h>
>
> #define BITS_PER_LONG (sizeof(long) * 8)
> #define NBITS(x) ((((x)-1)/BITS_PER_LONG)+1)
> @@ -69,6 +71,42 @@
>
> #define NAME_ELEMENT(element) [element] = #element
>
> +enum evtest_mode {
> + MODE_CAPTURE,
> + MODE_QUERY,
> +};
> +
> +static const struct query_mode {
> + const char *name;
> + int event_type;
> + int max;
> + int rq;
> +} query_modes[] = {
> + { "key", EV_KEY, KEY_MAX, EVIOCGKEY(KEY_MAX) },
> + { "led", EV_LED, LED_MAX, EVIOCGLED(LED_MAX) },
> + { "snd", EV_SND, SND_MAX, EVIOCGSND(SND_MAX) },
> + { "sw", EV_SW, SW_MAX, EVIOCGSW(SW_MAX) },
> +};
any particular reason you use "key", "led", etc. here instead of the
numerical value or the define name?
It seems to me that "evtest --query EV_KEY KEY_FOO" is a more consistent
UI than "evtest --query key KEY_FOO". And it may be useful to accept the
numerical values for EV_KEY etc. here as well.
> +
> +/**
> + * Look up an entry in the query_modes table by its textual name. The search
> + * is case-insensitive.
> + *
> + * @param mode The name of the entry to be found.
> + *
> + * @return The requested query_mode, or NULL if it could not be found.
> + */
> +static const struct query_mode *find_query_mode(const char *name)
> +{
> + int i;
> + for (i = 0; i < sizeof(query_modes) / sizeof(*query_modes); i++) {
> + const struct query_mode *mode = &query_modes[i];
> + if (strcasecmp(mode->name, name) == 0)
> + return mode;
> + }
> + return NULL;
> +}
> +
> static const char * const events[EV_MAX + 1] = {
> [0 ... EV_MAX] = NULL,
> NAME_ELEMENT(EV_SYN), NAME_ELEMENT(EV_KEY),
> @@ -480,6 +518,41 @@ static const char * const * const names[EV_MAX + 1] = {
> };
>
> /**
> + * Convert a string to a specific key/snd/led/sw code. The string can either
> + * be the name of the key in question (e.g. "SW_DOCK") or the numerical
> + * value, either as decimal (e.g. "5") or as hex (e.g. "0x5").
> + *
> + * @param mode The mode being queried (key, snd, led, sw)
> + * @param kstr The string to parse and convert
> + *
> + * @return The requested code's numerical value, or negative on error.
> + */
> +static int get_keycode(const struct query_mode *query_mode, const char *kstr)
> +{
> + if (isdigit(kstr[0])) {
> + unsigned long val;
> + errno = 0;
> + val = strtoul(kstr, NULL, 0);
> + if (errno) {
> + fprintf(stderr, "Could not interpret value %s\n", kstr);
> + return -1;
> + }
> + return (int) val;
> + } else {
> + const char * const *keynames = names[query_mode->event_type];
> + int i;
> +
> + for (i = 0; i < query_mode->max; i++) {
> + const char *name = keynames[i];
> + if (name && strcasecmp(name, kstr) == 0)
> + return i;
> + }
> +
> + return -1;
> + }
> +}
> +
> +/**
> * Filter for the AutoDevProbe scandir on /dev/input.
> *
> * @param dir The current directory entry provided by scandir.
> @@ -546,8 +619,18 @@ static char* scan_devices(void)
> */
> static void usage(void)
> {
> - printf("Usage: evtest /dev/input/eventX\n");
> - printf("Where X = input device number\n");
> + printf("USAGE:\n");
> + printf(" Grab mode:\n");
> + printf(" %s /dev/input/eventX\n", program_invocation_short_name);
> + printf("\n");
> + printf(" Query mode: (check exit code)\n");
> + printf(" %s --query /dev/input/eventX <type> <value>\n",
> + program_invocation_short_name);
> +
> + printf("\n");
> + printf("<type> is one of: key, sw, led, snd\n");
> + printf("<value> can either be a numerical value, or the textual name of the\n");
> + printf("key/switch/LED/sound being queried (e.g. SW_DOCK).\n");
> }
>
> /**
> @@ -743,14 +826,124 @@ static int do_capture(const char *device)
> return print_events(fd);
> }
>
> +/**
> + * Perform a one-shot state query on a specific device. The query can be of
> + * any known mode, on any valid keycode.
> + *
> + * @param device Path to the evdev device node that should be queried.
> + * @param query_mode The event type that is being queried (e.g. key, switch)
> + * @param keycode The code of the key/switch/sound/LED to be queried
> + * @return 0 if the state bit is unset, 10 if the state bit is set, 1 on error.
> + */
> +static int query_device(const char *device, const struct query_mode *query_mode, int keycode)
> +{
> + int fd;
> + int r;
> + unsigned char state[NBITS(query_mode->max)];
> +
> + fd = open(device, O_RDONLY);
> + if (fd < 0) {
> + perror("open");
> + return EXIT_FAILURE;
> + }
> +
> + memset(state, 0, sizeof(state));
> + r = ioctl(fd, query_mode->rq, state);
> + close(fd);
> +
> + if (r == -1) {
> + perror("ioctl");
> + return EXIT_FAILURE;
> + }
> +
> + if (test_bit(keycode, state))
> + return 10; /* different from EXIT_FAILURE */
> + else
> + return 0;
> +}
> +
> +/**
> + * Enter query mode. The requested event device will be queried for the state
> + * of a particular switch/key/sound/LED.
> + *
> + * @param device The device to query.
> + * @param mode The mode (event type) that is to be queried (snd, sw, key, led)
> + * @param keycode The key code to query the state of.
> + * @return 0 if the state bit is unset, 10 if the state bit is set.
> + */
> +static int do_query(const char *device, const char *event_type, const char *keyname)
> +{
> + const struct query_mode *query_mode;
> + int keycode;
> +
> + if (!device) {
> + fprintf(stderr, "Device argument is required for query.\n");
> + usage();
> + return EXIT_FAILURE;
> + }
> +
> + query_mode = find_query_mode(event_type);
> + if (!query_mode) {
> + fprintf(stderr, "Unrecognsied event type: %s\n", event_type);
^ typo
> + usage();
> + return EXIT_FAILURE;
> + }
> +
> + keycode = get_keycode(query_mode, keyname);
> + if (keycode < 0) {
> + fprintf(stderr, "Unrecognised key name: %s\n", keyname);
> + usage();
> + return EXIT_FAILURE;
> + } else if (keycode > query_mode->max) {
> + fprintf(stderr, "Key %d out of bounds.\n", keycode);
"key %d is out of bounds" maybe?
No other comments but please see Walter's comments in the other email.
Cheers,
Peter
> + return EXIT_FAILURE;
> + }
> +
> + return query_device(device, query_mode, keycode);
> +}
> +
> +static const struct option long_options[] = {
> + { "query", no_argument, NULL, MODE_QUERY },
> + { 0, },
> +};
> +
> int main (int argc, char **argv)
> {
> const char *device = NULL;
> + const char *keyname;
> + const char *event_type;
> + enum evtest_mode mode = MODE_CAPTURE;
> +
> + while (1) {
> + int option_index = 0;
> + int c = getopt_long(argc, argv, "", long_options, &option_index);
> + if (c == -1)
> + break;
> + switch (c) {
> + case MODE_QUERY:
> + mode = c;
> + break;
> + default:
> + usage();
> + break;
> + }
> + }
>
> - if (argc >= 2)
> - device = argv[1];
> + if (optind < argc)
> + device = argv[optind++];
> +
> + if (mode == MODE_CAPTURE)
> + return do_capture(device);
> +
> + if ((argc - optind) < 2) {
> + fprintf(stderr, "Query mode requires device, type and key parameters\n");
> + usage();
> + return EXIT_FAILURE;
> + }
>
> - return do_capture(device);
> + event_type = argv[optind++];
> + keyname = argv[optind++];
> + return do_query(device, event_type, keyname);
> }
>
> /* vim: set noexpandtab tabstop=8 shiftwidth=8: */
> diff --git a/evtest.txt b/evtest.txt
> index 685a4de..4cb1a18 100644
> --- a/evtest.txt
> +++ b/evtest.txt
> @@ -4,17 +4,33 @@ EVTEST(1)
> NAME
> ----
>
> - evtest - Input device event monitor
> + evtest - Input device event monitor and query tool
>
> SYNOPSIS
> --------
> - evtest "/dev/input/eventX"
> + evtest /dev/input/eventX
> +
> + evtest --query /dev/input/eventX <type> <value>
>
> DESCRIPTION
> -----------
> -evtest displays information on the input device specified on the command
> -line, including all the events supported by the device. It then monitors the
> -device and displays all the events layer events generated.
> +The first invocation type displayed above ("capture mode") causes evtest to
> +display information about the specified input device, including all the events
> +supported by the device. It then monitors the device and displays all the
> +events layer events generated.
> +
> +In the second invocation type ("query mode"), evtest performs a one-shot query
> +of the state of a specific key *value* of an event *type*.
> +
> +*type* is one of: *key*, *sw*, *snd*, *led*
> +
> +*value* can be either a decimal representation (e.g. 44), hex
> +(e.g. 0x2c), or the constant name (e.g. KEY_Z) of the key/switch/sound/LED
> +being queried.
> +
> +If the state bit is set (key pressed, switch on, ...), evtest exits with
> +code 0. If the state bit is unset (key depressed, switch off, ...), evtest
> +exits with code 10. No other output is generated.
>
> evtest needs to be able to read from the device; in most cases this means it
> must be run as root.
> @@ -32,6 +48,13 @@ when debugging a synaptics device from within X. VT switching to a TTY or
> shutting down the X server terminates this grab and synaptics devices can be
> debugged.
>
> +EXIT CODE
> +---------
> +evtest returns 1 on error.
> +
> +When used to query state, evtest returns 0 if the state bit is unset and
> +10 if the state bit is set.
> +
> SEE ALSO
> --------
> inputattach(1)
> --
> 1.7.6
>
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