27 lines
933 B
C
27 lines
933 B
C
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// Probe whether an input device is exclusively grabbed (EVIOCGRAB) by another
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// process (e.g. xochitl). If we can grab it, it was free -> a background watcher
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// can read it alongside xochitl. If EBUSY, xochitl holds it exclusively.
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#include <errno.h>
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#include <fcntl.h>
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#include <linux/input.h>
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#include <stdio.h>
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#include <string.h>
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#include <unistd.h>
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#include <sys/ioctl.h>
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int main(int argc, char **argv)
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{
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const char *dev = argc > 1 ? argv[1] : "/dev/input/event3";
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int fd = open(dev, O_RDONLY);
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if (fd < 0) { printf("%s: open failed: %s\n", dev, strerror(errno)); return 1; }
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int r = ioctl(fd, EVIOCGRAB, (void *)1);
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if (r == 0) {
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ioctl(fd, EVIOCGRAB, (void *)0); // release immediately
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printf("%s: NOT exclusively grabbed -> a watcher can read it\n", dev);
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} else {
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printf("%s: GRABBED by another process (%s)\n", dev, strerror(errno));
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}
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close(fd);
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return 0;
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}
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