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/*
* Copyright (c) 2012, Chris Andrews. All rights reserved.
*/
#include "usdt_internal.h"
#include <stdarg.h>
#include <string.h>
#include <stdio.h>
char *usdt_errors[] = {
"failed to allocate memory",
"failed to allocate page-aligned memory",
"no probes defined",
"failed to load DOF: %s",
"provider is already enabled",
"failed to unload DOF: %s",
"probe named %s:%s:%s:%s already exists",
"failed to remove probe %s:%s:%s:%s"
};
static void
free_probedef(usdt_probedef_t *pd)
{
int i;
switch (pd->refcnt) {
case 1:
free((char *)pd->function);
free((char *)pd->name);
if (pd->probe) {
usdt_free_tracepoints(pd->probe);
free(pd->probe);
}
for (i = 0; i < pd->argc; i++)
free(pd->types[i]);
free(pd);
break;
case 2:
pd->refcnt = 1;
break;
default:
break;
}
}
usdt_provider_t *
usdt_create_provider(const char *name, const char *module)
{
usdt_provider_t *provider;
if ((provider = malloc(sizeof *provider)) == NULL)
return NULL;
provider->name = strdup(name);
provider->module = strdup(module);
provider->probedefs = NULL;
provider->enabled = 0;
return provider;
}
usdt_probedef_t *
usdt_create_probe(const char *func, const char *name, size_t argc, const char **types)
{
int i;
usdt_probedef_t *p;
if (argc > USDT_ARG_MAX)
argc = USDT_ARG_MAX;
if ((p = malloc(sizeof *p)) == NULL)
return (NULL);
p->refcnt = 2;
p->function = strdup(func);
p->name = strdup(name);
p->argc = argc;
p->probe = NULL;
for (i = 0; i < argc; i++)
p->types[i] = strdup(types[i]);
return (p);
}
void
usdt_probe_release(usdt_probedef_t *probedef)
{
free_probedef(probedef);
}
int
usdt_provider_add_probe(usdt_provider_t *provider, usdt_probedef_t *probedef)
{
usdt_probedef_t *pd;
if (provider->probedefs != NULL) {
for (pd = provider->probedefs; (pd != NULL); pd = pd->next) {
if ((strcmp(pd->name, probedef->name) == 0) &&
(strcmp(pd->function, probedef->function) == 0)) {
usdt_error(provider, USDT_ERROR_DUP_PROBE,
provider->name, provider->module,
probedef->function, probedef->name);
return (-1);
}
}
}
probedef->next = NULL;
if (provider->probedefs == NULL)
provider->probedefs = probedef;
else {
for (pd = provider->probedefs; (pd->next != NULL); pd = pd->next) ;
pd->next = probedef;
}
return (0);
}
int
usdt_provider_remove_probe(usdt_provider_t *provider, usdt_probedef_t *probedef)
{
usdt_probedef_t *pd, *prev_pd = NULL;
if (provider->probedefs == NULL) {
usdt_error(provider, USDT_ERROR_NOPROBES);
return (-1);
}
for (pd = provider->probedefs; (pd != NULL);
prev_pd = pd, pd = pd->next) {
if ((strcmp(pd->name, probedef->name) == 0) &&
(strcmp(pd->function, probedef->function) == 0)) {
if (prev_pd == NULL)
provider->probedefs = pd->next;
else
prev_pd->next = pd->next;
return (0);
}
}
usdt_error(provider, USDT_ERROR_REMOVE_PROBE,
provider->name, provider->module,
probedef->function, probedef->name);
return (-1);
}
int
usdt_provider_enable(usdt_provider_t *provider)
{
usdt_strtab_t strtab;
usdt_dof_file_t *file;
usdt_probedef_t *pd;
int i;
size_t size;
usdt_dof_section_t sects[5];
if (provider->enabled == 1) {
usdt_error(provider, USDT_ERROR_ALREADYENABLED);
return (0); /* not fatal */
}
if (provider->probedefs == NULL) {
usdt_error(provider, USDT_ERROR_NOPROBES);
return (-1);
}
for (pd = provider->probedefs; pd != NULL; pd = pd->next) {
if ((pd->probe = malloc(sizeof(*pd->probe))) == NULL) {
usdt_error(provider, USDT_ERROR_MALLOC);
return (-1);
}
}
if ((usdt_strtab_init(&strtab, 0)) < 0) {
usdt_error(provider, USDT_ERROR_MALLOC);
return (-1);
}
if ((usdt_strtab_add(&strtab, provider->name)) == 0) {
usdt_error(provider, USDT_ERROR_MALLOC);
return (-1);
}
if ((usdt_dof_probes_sect(§s[0], provider, &strtab)) < 0)
return (-1);
if ((usdt_dof_prargs_sect(§s[1], provider)) < 0)
return (-1);
size = usdt_provider_dof_size(provider, &strtab);
if ((file = usdt_dof_file_init(provider, size)) == NULL)
return (-1);
if ((usdt_dof_proffs_sect(§s[2], provider, file->dof)) < 0)
return (-1);
if ((usdt_dof_prenoffs_sect(§s[3], provider, file->dof)) < 0)
return (-1);
if ((usdt_dof_provider_sect(§s[4], provider)) < 0)
return (-1);
for (i = 0; i < 5; i++)
usdt_dof_file_append_section(file, §s[i]);
usdt_dof_file_generate(file, &strtab);
usdt_dof_section_free((usdt_dof_section_t *)&strtab);
for (i = 0; i < 5; i++)
usdt_dof_section_free(§s[i]);
if ((usdt_dof_file_load(file, provider->module)) < 0) {
usdt_error(provider, USDT_ERROR_LOADDOF, strerror(errno));
return (-1);
}
provider->enabled = 1;
provider->file = file;
return (0);
}
int
usdt_provider_disable(usdt_provider_t *provider)
{
usdt_probedef_t *pd;
if (provider->enabled == 0)
return (0);
if ((usdt_dof_file_unload((usdt_dof_file_t *)provider->file)) < 0) {
usdt_error(provider, USDT_ERROR_UNLOADDOF, strerror(errno));
return (-1);
}
usdt_dof_file_free(provider->file);
provider->file = NULL;
/* We would like to free the tracepoints here too, but OS X
* (and to a lesser extent Illumos) struggle with this:
*
* If a provider is repeatedly disabled and re-enabled, and is
* allowed to reuse the same memory for its tracepoints, *and*
* there's a DTrace consumer running with enablings for these
* probes, tracepoints are not always cleaned up sufficiently
* that the newly-created probes work.
*
* Here, then, we will leak the memory holding the
* tracepoints, which serves to stop us reusing the same
* memory address for new tracepoints, avoiding the bug.
*/
for (pd = provider->probedefs; (pd != NULL); pd = pd->next) {
/* may have an as yet never-enabled probe on an
otherwise enabled provider */
if (pd->probe) {
/* usdt_free_tracepoints(pd->probe); */
free(pd->probe);
pd->probe = NULL;
}
}
provider->enabled = 0;
return (0);
}
void
usdt_provider_free(usdt_provider_t *provider)
{
usdt_probedef_t *pd, *next;
for (pd = provider->probedefs; pd != NULL; pd = next) {
next = pd->next;
free_probedef(pd);
}
free((char *)provider->name);
free((char *)provider->module);
free(provider);
}
int
usdt_is_enabled(usdt_probe_t *probe)
{
if (probe != NULL)
return (*probe->isenabled_addr)();
else
return 0;
}
void
usdt_fire_probe(usdt_probe_t *probe, size_t argc, void **nargv)
{
if (probe != NULL)
usdt_probe_args(probe->probe_addr, argc, nargv);
}
static void
usdt_verror(usdt_provider_t *provider, usdt_error_t error, va_list argp)
{
vasprintf(&provider->error, usdt_errors[error], argp);
}
void
usdt_error(usdt_provider_t *provider, usdt_error_t error, ...)
{
va_list argp;
va_start(argp, error);
usdt_verror(provider, error, argp);
va_end(argp);
}
char *
usdt_errstr(usdt_provider_t *provider)
{
return (provider->error);
}
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