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/* -*- linux-c -*-
*
* ctl.c - staprun control channel
*
* This file is part of systemtap, and is free software. You can
* redistribute it and/or modify it under the terms of the GNU General
* Public License (GPL); either version 2, or (at your option) any
* later version.
*
* Copyright (C) 2007 Red Hat Inc.
*/
#include "staprun.h"
int init_ctl_channel(const char *name, int verb)
{
char buf[PATH_MAX];
struct statfs st;
int old_transport = 0;
if (statfs("/sys/kernel/debug", &st) == 0 && (int)st.f_type == (int)DEBUGFS_MAGIC) {
if (sprintf_chk(buf, "/sys/kernel/debug/systemtap/%s/.cmd", name))
return -1;
} else {
old_transport = 1;
if (sprintf_chk(buf, "/proc/systemtap/%s/.cmd", name))
return -2;
}
if (access(buf, R_OK|W_OK) != 0)
return -5;
control_channel = open(buf, O_RDWR);
dbug(2, "Opened %s (%d)\n", buf, control_channel);
if (control_channel < 0) {
if (verb) {
if (attach_mod && errno == ENOENT)
err("ERROR: Can not attach. Module %s not running.\n", name);
else
perr("Couldn't open control channel '%s'", buf);
}
return -3;
}
if (set_clexec(control_channel) < 0)
return -4;
return old_transport;
}
void close_ctl_channel(void)
{
if (control_channel >= 0) {
dbug(2, "Closed ctl fd %d\n", control_channel);
close(control_channel);
control_channel = -1;
}
}
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