63 lines
1.1 KiB
C
63 lines
1.1 KiB
C
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// #include "monitor_user.h"
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#include <fcntl.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <sys/ioctl.h>
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#include <unistd.h>
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#define DEVICE "/dev/variable_monitor"
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int file_desc = -1;
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pid_t pid = 0;
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/// @brief start watch
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/// @param w_arg
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/// @return 0 means success, other means fail
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int start_watch() {
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if (file_desc < 0) {
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file_desc = open(DEVICE, 0);
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}
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if (file_desc < 0) {
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printf("Can't open device file: %s\n", DEVICE);
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return -1;
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}
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printf("1 \n");
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if (ioctl(file_desc, 2, &pid) < 0) {
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printf("ioctl failed\n");
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close(file_desc);
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return -1;
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}
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printf("2 \n");
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return 0;
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}
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/// @brief cancel watch
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/// @return 0 means success, other means fail
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int cancel_watch() {
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if (file_desc < 0) {
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file_desc = open(DEVICE, 0);
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}
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if (file_desc < 0) {
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printf("Device not open: %s,%d \n", DEVICE, file_desc);
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return file_desc;
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}
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close(file_desc);
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file_desc = -1;
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return 0;
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}
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int main(int argc, char **argv){
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if (argc != 2)
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printf("USAGE: unwind-pid <pid>\n");
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pid = atoi(argv[1]);
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printf("%d \n", pid);
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start_watch();
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cancel_watch();
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}
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