video-setup/dev/cli/v4l2_ctrl_cli.c

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "error.h"
#include "v4l2_ctrl.h"

static void usage(const char *prog) {
	fprintf(stderr,
		"Usage: %s <command> [args]\n"
		"\n"
		"Commands:\n"
		"  list                        List all /dev/video* devices\n"
		"  controls <device>           List all controls with current values\n"
		"  get      <device> <id>      Get a control value by ID (decimal or 0x hex)\n"
		"  set      <device> <id>=<value>\n"
		"                              Set a control value\n"
		"\n"
		"Examples:\n"
		"  %s list\n"
		"  %s controls /dev/video0\n"
		"  %s get /dev/video0 0x00980900\n"
		"  %s set /dev/video0 0x00980900=128\n",
		prog, prog, prog, prog, prog);
}

/* --- list --- */

static void on_device_found(const char *path, void *userdata) {
	(void)userdata;
	printf("  %s\n", path);
}

static int cmd_list(void) {
	printf("Video devices:\n");
	struct App_Error err = v4l2_ctrl_find_devices(on_device_found, NULL);
	if (!APP_IS_OK(err)) {
		app_error_print(&err);
		return 1;
	}
	return 0;
}

/* --- controls --- */

static void on_control(
	const struct V4l2_Ctrl_Desc *desc,
	uint32_t menu_count,
	const struct V4l2_Menu_Item *menu_items,
	void *userdata)
{
	(void)userdata;

	printf("  0x%08x  %-32s  %-9s  current=%-6d  default=%-6d  min=%-6d  max=%-6d",
		desc->id,
		desc->name,
		v4l2_ctrl_type_name(desc->type),
		desc->current_value,
		desc->default_value,
		desc->min,
		desc->max);

	if (desc->type == CTRL_TYPE_INTEGER || desc->type == CTRL_TYPE_INTEGER64) {
		printf("  step=%d", desc->step);
	}

	printf("\n");

	for (uint32_t i = 0; i < menu_count; i++) {
		if (desc->type == CTRL_TYPE_INTEGER_MENU) {
			printf("    [%u] %lld\n", menu_items[i].index, (long long)menu_items[i].value);
		} else {
			printf("    [%u] %s\n", menu_items[i].index, menu_items[i].name);
		}
	}
}

static int cmd_controls(const char *device) {
	struct V4l2_Ctrl_Handle *handle = NULL;
	struct App_Error err = v4l2_ctrl_open(device, &handle);
	if (!APP_IS_OK(err)) {
		app_error_print(&err);
		return 1;
	}

	printf("Controls on %s:\n", device);
	err = v4l2_ctrl_enumerate(handle, on_control, NULL);
	if (!APP_IS_OK(err)) {
		app_error_print(&err);
		v4l2_ctrl_close(handle);
		return 1;
	}

	v4l2_ctrl_close(handle);
	return 0;
}

/* --- get --- */

static int cmd_get(const char *device, const char *id_arg) {
	uint32_t id = (uint32_t)strtoul(id_arg, NULL, 0);

	struct V4l2_Ctrl_Handle *handle = NULL;
	struct App_Error err = v4l2_ctrl_open(device, &handle);
	if (!APP_IS_OK(err)) {
		app_error_print(&err);
		return 1;
	}

	int32_t value;
	err = v4l2_ctrl_get(handle, id, &value);
	if (!APP_IS_OK(err)) {
		app_error_print(&err);
		v4l2_ctrl_close(handle);
		return 1;
	}

	printf("0x%08x = %d\n", id, value);

	v4l2_ctrl_close(handle);
	return 0;
}

/* --- set --- */

static int cmd_set(const char *device, const char *assignment) {
	char id_str[64];
	const char *eq = strchr(assignment, '=');
	if (!eq) {
		fprintf(stderr, "Expected <id>=<value>, got: %s\n", assignment);
		return 1;
	}

	size_t id_len = (size_t)(eq - assignment);
	if (id_len >= sizeof(id_str)) {
		fprintf(stderr, "ID string too long\n");
		return 1;
	}
	memcpy(id_str, assignment, id_len);
	id_str[id_len] = '\0';

	uint32_t id    = (uint32_t)strtoul(id_str, NULL, 0);
	int32_t  value = (int32_t)strtol(eq + 1, NULL, 0);

	struct V4l2_Ctrl_Handle *handle = NULL;
	struct App_Error err = v4l2_ctrl_open(device, &handle);
	if (!APP_IS_OK(err)) {
		app_error_print(&err);
		return 1;
	}

	err = v4l2_ctrl_set(handle, id, value);
	if (!APP_IS_OK(err)) {
		app_error_print(&err);
		v4l2_ctrl_close(handle);
		return 1;
	}

	printf("0x%08x set to %d\n", id, value);

	v4l2_ctrl_close(handle);
	return 0;
}

/* --- main --- */

int main(int argc, char **argv) {
	if (argc < 2) {
		usage(argv[0]);
		return 1;
	}

	const char *cmd = argv[1];

	if (strcmp(cmd, "list") == 0) {
		return cmd_list();
	}

	if (strcmp(cmd, "controls") == 0) {
		if (argc < 3) {
			fprintf(stderr, "controls requires a device argument\n");
			return 1;
		}
		return cmd_controls(argv[2]);
	}

	if (strcmp(cmd, "get") == 0) {
		if (argc < 4) {
			fprintf(stderr, "get requires: <device> <id>\n");
			return 1;
		}
		return cmd_get(argv[2], argv[3]);
	}

	if (strcmp(cmd, "set") == 0) {
		if (argc < 4) {
			fprintf(stderr, "set requires: <device> <id>=<value>\n");
			return 1;
		}
		return cmd_set(argv[2], argv[3]);
	}

	fprintf(stderr, "Unknown command: %s\n\n", cmd);
	usage(argv[0]);
	return 1;
}