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#include "git-compat-util.h"
#include "strbuf.h"
#include "strvec.h"
#include "trace2.h"
#include <sys/sysctl.h>
/*
* An arbitrarily chosen value to limit the depth of the ancestor chain.
*/
#define NR_PIDS_LIMIT 10
/*
* Get the process name and parent PID for a given PID using sysctl().
* Returns 0 on success, -1 on failure.
*/
static int get_proc_info(pid_t pid, struct strbuf *name, pid_t *ppid)
{
int mib[4];
struct kinfo_proc proc;
size_t size = sizeof(proc);
mib[0] = CTL_KERN;
mib[1] = KERN_PROC;
mib[2] = KERN_PROC_PID;
mib[3] = pid;
if (sysctl(mib, 4, &proc, &size, NULL, 0) < 0)
return -1;
if (size == 0)
return -1;
strbuf_addstr(name, proc.kp_proc.p_comm);
*ppid = proc.kp_eproc.e_ppid;
return 0;
}
/*
* Recursively push process names onto the ancestry array.
* We guard against cycles by limiting the depth to NR_PIDS_LIMIT.
*/
static void push_ancestry_name(struct strvec *names, pid_t pid, int depth)
{
struct strbuf name = STRBUF_INIT;
pid_t ppid;
if (depth >= NR_PIDS_LIMIT)
return;
if (pid <= 0)
return;
if (get_proc_info(pid, &name, &ppid) < 0)
goto cleanup;
strvec_push(names, name.buf);
/*
* Recurse to the parent process. Stop if ppid not valid
* or if we've reached ourselves (cycle).
*/
if (ppid && ppid != pid)
push_ancestry_name(names, ppid, depth + 1);
cleanup:
strbuf_release(&name);
}
void trace2_collect_process_info(enum trace2_process_info_reason reason)
{
struct strvec names = STRVEC_INIT;
if (!trace2_is_enabled())
return;
switch (reason) {
case TRACE2_PROCESS_INFO_STARTUP:
push_ancestry_name(&names, getppid(), 0);
if (names.nr)
trace2_cmd_ancestry(names.v);
strvec_clear(&names);
break;
case TRACE2_PROCESS_INFO_EXIT:
/*
* The Windows version of this calls its
* get_peak_memory_info() here. We may want to insert
* similar process-end statistics here in the future.
*/
break;
default:
BUG("trace2_collect_process_info: unknown reason '%d'", reason);
}
}
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