Attachment 112824 Details for Bug 88572 – A patch to add a grab flag for evtest

[patch] A patch to add a grab flag for evtest

1.29-add-grab-flag.patch (text/plain), 3.87 KB, created by Joseph Hwang on 2015-01-26 05:10:52 UTC

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Creator: Joseph Hwang

Created: 2015-01-26 05:10:52 UTC

Size: 3.87 KB

patch

obsolete

>From b472cf36a65c3a7eeb17c3860ecead85e67e56cd 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
>
>This patch grabs the device when --grab command line option is
>present. In this way, no other processes are able to access the
>device.
>
>TEST=Check that the cursor is frozen when --grab option is specified.
>$ evtest --grab
>---
> evtest.c   | 38 +++++++++++++++++++++++++++++++++++---
> evtest.txt |  6 +++++-
> 2 files changed, 40 insertions(+), 4 deletions(-)
>
>diff --git a/evtest.c b/evtest.c
>index 74230ea..6a2b7a1 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)
>@@ -93,6 +97,17 @@ static const struct query_mode {
> 	{ "EV_SW",  EV_SW, SW_MAX, EVIOCGSW(SW_MAX) },
> };
> 
>+static int grab_flag = 0;
>+static volatile int stop = 0;
>+
>+/**
>+ * An interrupt handler to ungrab the device.
>+ */
>+static void interrupt_handler(void)
>+{
>+	stop = 1;
>+}
>+
> /**
>  * Look up an entry in the query_modes table by its textual name.
>  *
>@@ -675,8 +690,9 @@ 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",
>@@ -768,8 +784,15 @@ static int print_events(int fd)
> {
> 	struct input_event ev[64];
> 	int i, rd;
>+	fd_set rdfs;
>+
>+	FD_ZERO(&rdfs);
>+	FD_SET(fd, &rdfs);
> 
> 	while (1) {
>+		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)) {
>@@ -800,6 +823,9 @@ static int print_events(int fd)
> 		}
> 
> 	}
>+
>+	ioctl(fd, EVIOCGRAB, (void*)0);
>+	return EXIT_SUCCESS;
> }
> 
> /**
>@@ -814,7 +840,7 @@ static int test_grab(int fd)
> 
> 	rc = ioctl(fd, EVIOCGRAB, (void*)1);
> 
>-	if (!rc)
>+	if (!rc && !grab_flag)
> 		ioctl(fd, EVIOCGRAB, (void*)0);
> 
> 	return rc;
>@@ -878,6 +904,9 @@ static int do_capture(const char *device)
> 		printf("***********************************************\n");
> 	}
> 
>+	signal(SIGINT, interrupt_handler);
>+	signal(SIGTERM, interrupt_handler);
>+
> 	return print_events(fd);
> }
> 
>@@ -954,6 +983,7 @@ 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, },
>@@ -972,6 +1002,8 @@ int main (int argc, char **argv)
> 		if (c == -1)
> 			break;
> 		switch (c) {
>+		case 0:
>+			break;
> 		case MODE_QUERY:
> 			mode = c;
> 			break;
>diff --git a/evtest.txt b/evtest.txt
>index b614482..0a8d3cb 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 specified in the capture mode, evtest would grab
>+the device for exclusive access during its execution period. No other
>+processes are allowed to access the device simultaneously in this case.
>+
> 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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