73 lines
1.4 KiB
C
73 lines
1.4 KiB
C
#include <sys/types.h>
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#include <sys/stat.h>
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#include <stdlib.h>
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#include <stdio.h>
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#include <fcntl.h>
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#include <unistd.h>
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#include <linux/fs.h>
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#include <linux/limits.h>
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#define NR_OPEN 1024
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void logg(int num){
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printf("You are in: %d\n",num);
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}
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int _daemon(int nochdir, int noclose){
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pid_t pid, sid;
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// pid_t defined in sys/types.h
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// pid_t is a signed int data type
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logg(1);
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pid = fork(); // fork of the parent process
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// fork() function defined in unistd.h
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logg(2);
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if (pid < 0){
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logg(3);
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exit(EXIT_FAILURE); // exit and EXIT_FAILURE defined in stdlib.h
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}
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else if (pid > 0){
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logg(4);
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exit(EXIT_SUCCESS);
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}
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logg(5);
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sid = setsid();
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logg(6);
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if (sid < 0) {
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logg(7);
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exit(EXIT_FAILURE);
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}
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logg(8);
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if ((chdir("/")) < 0) {
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logg(10);
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exit(EXIT_FAILURE);
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}
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logg(11);
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if (!noclose) {
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logg(12);
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for (int i = 0; i < NR_OPEN; i++){
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logg(13);
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close(i);
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// close(STDOUT_FILENO); => close(1);
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// close(STDERR_FILENO); => close(2);
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}
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open("/dev/null", O_RDWR);
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logg(14);
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dup(0);
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dup(0);
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}
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while (1) {
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logg(15);
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int status = system("/usr/lib/cdaemontmp/info");
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// TODO SECURITY ISSUE
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// LINK https://stackoverflow.com/questions/5237482/how-do-i-execute-an-external-program-within-c-code-in-linux-with-arguments#
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sleep(1);
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}
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logg(16);
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exit(EXIT_SUCCESS);
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} |