37 lines
745 B
C
37 lines
745 B
C
#include <stdio.h>
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#include <string.h>
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#include <fcntl.h>
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#include <unistd.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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int main(int argc, char *argv[])
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{
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struct stat st;
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char buf[1024];
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int len, fd;
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if (argc != 2) {
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fprintf(stderr, "Usage: %s <iface>\n", argv[0]);
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return 1;
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}
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snprintf(buf, sizeof(buf), "/sys/class/backlight/%s/brightness", argv[1]);
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fd = open(buf, O_RDWR);
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if (fd < 0 || fstat(fd, &st) || major(st.st_dev)) {
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fprintf(stderr, "Cannot access backlight interface '%s'\n", argv[1]);
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return 1;
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}
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while (fgets(buf, sizeof(buf), stdin)) {
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len = strlen(buf);
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if (write(fd, buf, len) != len) {
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fprintf(stderr, "Failed to update backlight interface '%s'\n", argv[1]);
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return 2;
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}
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}
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return 0;
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}
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