Attachment 112927 Details for Bug 88572 – A patch adding a grab flag for evtest

[patch] A patch adding a grab flag for evtest

1.32-add-grab-flag.patch (text/plain), 5.06 KB, created by Joseph Hwang on 2015-01-29 06:48:40 UTC

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Creator: Joseph Hwang

Created: 2015-01-29 06:48:40 UTC

Size: 5.06 KB

patch

obsolete

>From 53cf280c9a6926abfdd7e9fca8dfa412c37c7202 Mon Sep 17 00:00:00 2001
>From: Joseph Hwang <josephsih@chromium.org>
>Date: Fri, 23 Jan 2015 16:22:16 +0800
>Subject: [PATCH] add grab flag
>
>If the --grab flag is given in capture mode, evtest keeps an EVIOCGRAB
>on the device. While this grab is active, other processes will not
>receive events from the kernel devices. The grab is released again
>when evtest quits.
>
>TEST=Check that the cursor is frozen when --grab option is specified.
>$ evtest --grab
>---
> evtest.c   | 45 +++++++++++++++++++++++++++++++++++++--------
> evtest.txt |  6 +++++-
> 2 files changed, 42 insertions(+), 9 deletions(-)
>
>diff --git a/evtest.c b/evtest.c
>index 0fe7aa6..7f0909d 100644
>--- a/evtest.c
>+++ b/evtest.c
>@@ -55,6 +55,10 @@
> #include <errno.h>
> #include <getopt.h>
> #include <ctype.h>
>+#include <signal.h>
>+#include <sys/time.h>
>+#include <sys/types.h>
>+#include <unistd.h>
> 
> #define BITS_PER_LONG (sizeof(long) * 8)
> #define NBITS(x) ((((x)-1)/BITS_PER_LONG)+1)
>@@ -100,6 +104,14 @@ static const struct query_mode {
> 	{ "EV_SW",  EV_SW, SW_MAX, EVIOCGSW(SW_MAX) },
> };
> 
>+static int grab_flag = 0;
>+static volatile sig_atomic_t stop = 0;
>+
>+static void interrupt_handler(int sig)
>+{
>+	stop = 1;
>+}
>+
> /**
>  * Look up an entry in the query_modes table by its textual name.
>  *
>@@ -744,8 +756,9 @@ static int version(void)
> static int usage(void)
> {
> 	printf("USAGE:\n");
>-	printf(" Grab mode:\n");
>-	printf("   %s /dev/input/eventX\n", program_invocation_short_name);
>+	printf(" Capture mode:\n");
>+	printf("   %s [--grab] /dev/input/eventX\n", program_invocation_short_name);
>+	printf("     --grab  grab the device for exclusive access\n");
> 	printf("\n");
> 	printf(" Query mode: (check exit code)\n");
> 	printf("   %s --query /dev/input/eventX <type> <value>\n",
>@@ -887,8 +900,15 @@ static int print_events(int fd)
> {
> 	struct input_event ev[64];
> 	int i, rd;
>+	fd_set rdfs;
> 
>-	while (1) {
>+	FD_ZERO(&rdfs);
>+	FD_SET(fd, &rdfs);
>+
>+	while (!stop) {
>+		select(fd + 1, &rdfs, NULL, NULL, NULL);
>+		if (stop)
>+			break;
> 		rd = read(fd, ev, sizeof(struct input_event) * 64);
> 
> 		if (rd < (int) sizeof(struct input_event)) {
>@@ -922,6 +942,9 @@ static int print_events(int fd)
> 		}
> 
> 	}
>+
>+	ioctl(fd, EVIOCGRAB, (void*)0);
>+	return EXIT_SUCCESS;
> }
> 
> /**
>@@ -930,13 +953,13 @@ static int print_events(int fd)
>  * @param fd The file descriptor to the device.
>  * @return 0 if the grab was successful, or 1 otherwise.
>  */
>-static int test_grab(int fd)
>+static int test_grab(int fd, int grab_flag)
> {
> 	int rc;
> 
> 	rc = ioctl(fd, EVIOCGRAB, (void*)1);
> 
>-	if (!rc)
>+	if (rc == 0 && !grab_flag)
> 		ioctl(fd, EVIOCGRAB, (void*)0);
> 
> 	return rc;
>@@ -949,7 +972,7 @@ static int test_grab(int fd)
>  * @param device The device to monitor, or NULL if the user should be prompted.
>  * @return 0 on success, non-zero on error.
>  */
>-static int do_capture(const char *device)
>+static int do_capture(const char *device, int grab_flag)
> {
> 	int fd;
> 	char *filename = NULL;
>@@ -987,7 +1010,7 @@ static int do_capture(const char *device)
> 
> 	printf("Testing ... (interrupt to exit)\n");
> 
>-	if (test_grab(fd))
>+	if (test_grab(fd, grab_flag))
> 	{
> 		printf("***********************************************\n");
> 		printf("  This device is grabbed by another process.\n");
>@@ -1001,6 +1024,9 @@ static int do_capture(const char *device)
> 		printf("***********************************************\n");
> 	}
> 
>+	signal(SIGINT, interrupt_handler);
>+	signal(SIGTERM, interrupt_handler);
>+
> 	free(filename);
> 
> 	return print_events(fd);
>@@ -1083,6 +1109,7 @@ static int do_query(const char *device, const char *event_type, const char *keyn
> }
> 
> static const struct option long_options[] = {
>+	{ "grab", no_argument, &grab_flag, 1 },
> 	{ "query", no_argument, NULL, MODE_QUERY },
> 	{ "version", no_argument, NULL, MODE_VERSION },
> 	{ 0, },
>@@ -1101,6 +1128,8 @@ int main (int argc, char **argv)
> 		if (c == -1)
> 			break;
> 		switch (c) {
>+		case 0:
>+			break;
> 		case MODE_QUERY:
> 			mode = c;
> 			break;
>@@ -1115,7 +1144,7 @@ int main (int argc, char **argv)
> 		device = argv[optind++];
> 
> 	if (mode == MODE_CAPTURE)
>-		return do_capture(device);
>+		return do_capture(device, grab_flag);
> 
> 	if ((argc - optind) < 2) {
> 		fprintf(stderr, "Query mode requires device, type and key parameters\n");
>diff --git a/evtest.txt b/evtest.txt
>index ab89afb..5fd15b0 100644
>--- a/evtest.txt
>+++ b/evtest.txt
>@@ -8,7 +8,7 @@ NAME
> 
> SYNOPSIS
> --------
>-     evtest /dev/input/eventX
>+     evtest [--grab] /dev/input/eventX
> 
>      evtest --query /dev/input/eventX <type> <value>
> 
>@@ -19,6 +19,10 @@ 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.
> 
>+If the --grab flag is given in capture mode, evtest keeps an EVIOCGRAB on the
>+device. While this grab is active, other processes will not receive events
>+from the kernel devices. The grab is released again when evtest quits.
>+
> 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*.
> 
>-- 
>2.2.0.rc0.207.ga3a616c
>

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