Hi,
as a reference (and nicer rendering), I was asking this question on stack
overflow but got pointed here. I would be very thankful for your help:
http://stackoverflow.com/questions/37033240/dtrace-from-c-does-not-yield-same-profiling-result-compared-to-command-line
<http://stackoverflow.com/questions/37033240/dtrace-from-c-does-not-yield-same-profiling-result-compared-to-command-line>
I want to programmatically trace stacks from C for Node.js (JS addresses aside).
The following command gives me stacks with resolved c++ symbols.
sudo dtrace -C -n 'profile-101 /pid == 13221/ { ustack() }‘
The following C code however only returns addresses for Node's C/C++ code. What
would be the equivalent?
#include <dtrace.h>
#include <signal.h>
#include <stdio.h>
struct ps_prochandle *g_pr;
static dtrace_hdl_t* g_dtp;
static int chewrec (const dtrace_probedata_t *data, const dtrace_recdesc_t
*rec, void *arg) {
// A NULL rec indicates that we've processed the last record.
if (rec == NULL) {
return (DTRACE_CONSUME_NEXT);
}
return (DTRACE_CONSUME_THIS);
}
static const char* g_prog =
"#pragma D option switchrate=1000hz\n"
"profile-1ms /pid == 13221/ {\n"
"ustack();\n"
"}";
static int g_intr;
static int g_exited;
static void intr (int signo) {
g_intr = 1;
}
int main (int argc, char** argv) {
int err;
if ((g_dtp = dtrace_open(DTRACE_VERSION, 0, &err)) == NULL) {
fprintf(stderr, "failed to initialize dtrace: %s\n", dtrace_errmsg(NULL,
err));
return -1;
}
printf("Dtrace initialized\n");
(void) dtrace_setopt(g_dtp, "bufsize", "4m");
(void) dtrace_setopt(g_dtp, "aggsize", "4m");
printf("dtrace options set\n");
dtrace_prog_t* prog;
if ((prog = dtrace_program_strcompile(g_dtp, g_prog, DTRACE_PROBESPEC_NAME,
DTRACE_C_CPP, 0, NULL)) == NULL) {
fprintf(stderr, "failed to compile dtrace program\n");
return -1;
} else {
printf("dtrace program compiled\n");
}
dtrace_proginfo_t info;
if (dtrace_program_exec(g_dtp, prog, &info) == -1) {
fprintf(stderr, "failed to enable dtrace probes\n");
return -1;
} else {
printf("dtrace probes enabled\n");
}
struct sigaction act;
(void) sigemptyset(&act.sa_mask);
act.sa_flags = 0;
act.sa_handler = intr;
(void) sigaction(SIGINT, &act, NULL);
(void) sigaction(SIGTERM, &act, NULL);
if (dtrace_go(g_dtp) != 0) {
fprintf(stderr, "could not start instrumentation\n");
return -1;
} else {
printf("instrumentation started ..\n");
}
int done = 0;
do {
if (!g_intr && !done) {
dtrace_sleep(g_dtp);
}
if (done || g_intr || g_exited) {
done = 1;
if (dtrace_stop(g_dtp) == -1) {
fprintf(stderr, "could not stop tracing\n");
return -1;
}
}
switch (dtrace_work(g_dtp, stdout, NULL, chewrec, NULL)) {
case DTRACE_WORKSTATUS_DONE:
done = 1;
break;
case DTRACE_WORKSTATUS_OKAY:
break;
default:
fprintf(stderr, "processing aborted");
return -1;
}
} while (!done);
printf("closing dtrace\n");
dtrace_close(g_dtp);
return 0;
}
-------------------------------------------
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