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#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/syscall.h>
#define __NR_ptree 313
struct prinfo {
long state;
pid_t pid;
pid_t parent_pid;
pid_t first_child_pid;
pid_t next_sibling_pid;
long uid;
char comm[64];
};
static inline int ptree(struct prinfo *processes, unsigned int *count)
{
return syscall(__NR_ptree, processes, count);
}
static pid_t find_parent(struct prinfo *processes, unsigned int count, pid_t pid)
{
int i;
for (i = 0; i < count; ++i) {
if (processes[i].pid == pid)
return processes[i].parent_pid;
}
return 0;
}
static int hilariously_inefficient_method_of_finding_indentation_level(struct prinfo *processes, unsigned int count, pid_t pid)
{
int indentation = 0;
while((pid = find_parent(processes, count, pid)))
++indentation;
return indentation;
/* Bonus points if you can find a reasonable _looking_
* algorithm that is even more inefficient. */
}
int main(int argc, char *argv[])
{
struct prinfo *processes;
unsigned int count, indentation, i, j;
pid_t last_ppid;
indentation = 0;
count = 32768;
processes = malloc(sizeof(struct prinfo) * count);
if (!processes) {
perror("processes");
return EXIT_FAILURE;
}
memset(processes, 0, sizeof(struct prinfo) * count);
if (ptree(processes, &count)) {
perror("ptree");
return EXIT_FAILURE;
}
for (i = 0; i < count; ++i) {
indentation = hilariously_inefficient_method_of_finding_indentation_level(processes, count, processes[i].pid);
for (j = 0; j < indentation; ++j)
putchar('\t');
printf("%s,%d,%ld,%d,%d,%d,%ld\n", processes[i].comm, processes[i].pid,
processes[i].state, processes[i].parent_pid, processes[i].first_child_pid,
processes[i].next_sibling_pid, processes[i].uid);
}
printf("%d processes\n", count);
return EXIT_SUCCESS;
}
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