53 lines
937 B
C
53 lines
937 B
C
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#include <errno.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <fcntl.h>
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#include <unistd.h>
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int main() {
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#define BIOS_DATA_AREA 0x400
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#define BDA_KEYBOARD_STATUS_FLAGS_4 0x97
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#define BDA_KSF4_NUMLOCK_MASK 0x02
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int fdmem;
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char c;
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errno=0;
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fdmem = open("/dev/mem", O_RDONLY);
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if (fdmem < 0) {
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fprintf(stderr, "Couldn't open /dev/mem; %s\n", strerror(errno));
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goto finish;
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}
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if (lseek(fdmem, BIOS_DATA_AREA + BDA_KEYBOARD_STATUS_FLAGS_4, SEEK_SET) == (off_t) -1) {
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fprintf(stderr, "Failed to seek /dev/mem: %s\n", strerror(errno));
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goto finish;
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}
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if (read (fdmem, &c, sizeof(char)) == -1) {
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fprintf(stderr, "Failed to read /dev/mem: %s\n", strerror(errno));
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goto finish;
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}
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if (c & BDA_KSF4_NUMLOCK_MASK)
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printf("on\n");
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else
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printf("off\n");
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finish:
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close(fdmem);
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if (errno)
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{
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printf("unknown\n");
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exit(EXIT_FAILURE);
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}
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return 0;
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}
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