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lighttpd1.4/src/mod_rrdtool.c

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#include "first.h"
#include "base.h"
#include "fdevent.h"
#include "log.h"
#include "plugin.h"
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>
#include <time.h>
typedef struct {
const buffer *path_rrd;
off_t requests;
off_t bytes_written;
off_t bytes_read;
} rrd_config;
typedef struct {
rrd_config *rrd;
} plugin_config;
typedef struct {
PLUGIN_DATA;
plugin_config defaults;
plugin_config conf;
int read_fd;
int write_fd;
pid_t rrdtool_pid;
pid_t srv_pid;
int rrdtool_running;
const buffer *path_rrdtool_bin;
server *srv;
} plugin_data;
INIT_FUNC(mod_rrd_init) {
return calloc(1, sizeof(plugin_data));
}
static void mod_rrd_free_config(plugin_data * const p) {
if (NULL == p->cvlist) return;
/* (init i to 0 if global context; to 1 to skip empty global context) */
for (int i = !p->cvlist[0].v.u2[1], used = p->nconfig; i < used; ++i) {
config_plugin_value_t *cpv = p->cvlist + p->cvlist[i].v.u2[0];
for (; -1 != cpv->k_id; ++cpv) {
switch (cpv->k_id) {
case 0: /* rrdtool.db-name */
if (cpv->vtype == T_CONFIG_LOCAL) free(cpv->v.v);
break;
default:
break;
}
}
}
}
FREE_FUNC(mod_rrd_free) {
plugin_data *p = p_d;
if (NULL == p->srv) return;
mod_rrd_free_config(p);
if (p->read_fd >= 0) close(p->read_fd);
if (p->write_fd >= 0) close(p->write_fd);
if (p->rrdtool_pid > 0 && p->srv_pid == p->srv->pid) {
/* collect status (blocking) */
fdevent_waitpid(p->rrdtool_pid, NULL, 0);
}
}
static int mod_rrd_create_pipe(server *srv, plugin_data *p) {
char *args[3];
int to_rrdtool_fds[2];
int from_rrdtool_fds[2];
/* mod_rrdtool does not work with server.max-workers > 0
* since the data between workers is not aggregated,
* and it is not valid to send data to rrdtool more than once a sec
* (which would happen with multiple workers writing to same pipe)
* If pipes were to be shared, then existing pipes would need to be
* reused here, if they already exist (not -1), and after flushing
* existing contents (read and discard from read-end of pipes). */
if (pipe(to_rrdtool_fds)) {
log_perror(srv->errh, __FILE__, __LINE__, "pipe()");
return 0;
}
if (pipe(from_rrdtool_fds)) {
log_perror(srv->errh, __FILE__, __LINE__, "pipe()");
close(to_rrdtool_fds[0]);
close(to_rrdtool_fds[1]);
return 0;
}
fdevent_setfd_cloexec(to_rrdtool_fds[1]);
fdevent_setfd_cloexec(from_rrdtool_fds[0]);
const char * const path_rrdtool_bin = p->path_rrdtool_bin
? p->path_rrdtool_bin->ptr
: "/usr/bin/rrdtool";
*(const char **)&args[0] = path_rrdtool_bin;
*(const char **)&args[1] = "-";
args[2] = NULL;
p->rrdtool_pid = fdevent_fork_execve(args[0], args, NULL, to_rrdtool_fds[0], from_rrdtool_fds[1], -1, -1);
if (-1 != p->rrdtool_pid) {
close(from_rrdtool_fds[1]);
close(to_rrdtool_fds[0]);
if (p->read_fd >= 0) close(p->read_fd);
if (p->write_fd >= 0) close(p->write_fd);
p->write_fd = to_rrdtool_fds[1];
p->read_fd = from_rrdtool_fds[0];
p->srv_pid = srv->pid;
return 1;
} else {
log_perror(srv->errh, __FILE__, __LINE__,
"fork/exec(%s)", path_rrdtool_bin);
close(to_rrdtool_fds[0]);
close(to_rrdtool_fds[1]);
close(from_rrdtool_fds[0]);
close(from_rrdtool_fds[1]);
return 0;
}
}
__attribute_noinline__
static int mod_rrd_exec(server *srv, plugin_data *p) {
return (p->rrdtool_running = mod_rrd_create_pipe(srv, p));
}
static void mod_rrd_merge_config_cpv(plugin_config * const pconf, const config_plugin_value_t * const cpv) {
switch (cpv->k_id) { /* index into static config_plugin_keys_t cpk[] */
case 0: /* rrdtool.db-name */
if (cpv->vtype == T_CONFIG_LOCAL) pconf->rrd = cpv->v.v;
break;
case 1: /* rrdtool.binary */ /* T_CONFIG_SCOPE_SERVER */
break;
default:/* should not happen */
return;
}
}
static void mod_rrd_merge_config(plugin_config * const pconf, const config_plugin_value_t *cpv) {
do {
mod_rrd_merge_config_cpv(pconf, cpv);
} while ((++cpv)->k_id != -1);
}
static void mod_rrd_patch_config(request_st * const r, plugin_data * const p) {
p->conf = p->defaults; /* copy small struct instead of memcpy() */
/*memcpy(&p->conf, &p->defaults, sizeof(plugin_config));*/
for (int i = 1, used = p->nconfig; i < used; ++i) {
if (config_check_cond(r, (uint32_t)p->cvlist[i].k_id))
mod_rrd_merge_config(&p->conf, p->cvlist + p->cvlist[i].v.u2[0]);
}
}
SETDEFAULTS_FUNC(mod_rrd_set_defaults) {
static const config_plugin_keys_t cpk[] = {
{ CONST_STR_LEN("rrdtool.db-name"),
T_CONFIG_STRING,
T_CONFIG_SCOPE_CONNECTION }
,{ CONST_STR_LEN("rrdtool.binary"),
T_CONFIG_STRING,
T_CONFIG_SCOPE_SERVER }
,{ NULL, 0,
T_CONFIG_UNSET,
T_CONFIG_SCOPE_UNSET }
};
plugin_data * const p = p_d;
p->srv = srv;
if (!config_plugin_values_init(srv, p, cpk, "mod_rrdtool"))
return HANDLER_ERROR;
int activate = 0;
/* process and validate config directives
* (init i to 0 if global context; to 1 to skip empty global context) */
for (int i = !p->cvlist[0].v.u2[1]; i < p->nconfig; ++i) {
config_plugin_value_t *cpv = p->cvlist + p->cvlist[i].v.u2[0];
for (; -1 != cpv->k_id; ++cpv) {
switch (cpv->k_id) {
case 0: /* rrdtool.db-name */
if (!buffer_string_is_empty(cpv->v.b)) {
rrd_config *rrd = calloc(1, sizeof(rrd_config));
force_assert(rrd);
rrd->path_rrd = cpv->v.b;
cpv->v.v = rrd;
cpv->vtype = T_CONFIG_LOCAL;
activate = 1;
}
break;
case 1: /* rrdtool.binary */ /* T_CONFIG_SCOPE_SERVER */
if (!buffer_string_is_empty(cpv->v.b))
p->path_rrdtool_bin = cpv->v.b; /*(store directly in p)*/
break;
default:/* should not happen */
break;
}
}
}
/* initialize p->defaults from global config context */
if (p->nconfig > 0 && p->cvlist->v.u2[1]) {
const config_plugin_value_t *cpv = p->cvlist + p->cvlist->v.u2[0];
if (-1 != cpv->k_id)
mod_rrd_merge_config(&p->defaults, cpv);
}
p->rrdtool_running = 0;
p->read_fd = -1;
p->write_fd = -1;
return (!activate || mod_rrd_exec(srv, p)) ? HANDLER_GO_ON : HANDLER_ERROR;
}
/* read/write wrappers to catch EINTR */
/* write to blocking socket; blocks until all data is sent, write returns 0 or an error (apart from EINTR) occurs. */
static ssize_t safe_write(int fd, const void *buf, size_t count) {
ssize_t res, sum = 0;
for (;;) {
res = write(fd, buf, count);
if (res >= 0) {
sum += res;
/* do not try again if res == 0 */
if (res == 0 || (size_t) res == count) return sum;
count -= res;
buf = (const char*) buf + res;
continue;
}
switch (errno) {
case EINTR:
continue;
default:
return -1;
}
}
}
/* this assumes we get enough data on a successful read */
static ssize_t safe_read(int fd, char *buf, size_t sz) {
ssize_t res;
do {
res = read(fd, buf, sz-1);
} while (-1 == res && errno == EINTR);
if (res >= 0) buf[res] = '\0';
return res;
}
static int mod_rrdtool_create_rrd(server *srv, plugin_data *p, rrd_config *s, char *resp, size_t respsz) {
struct stat st;
/* check if DB already exists */
if (0 == stat(s->path_rrd->ptr, &st)) {
/* check if it is plain file */
if (!S_ISREG(st.st_mode)) {
log_error(srv->errh, __FILE__, __LINE__,
"not a regular file: %s", s->path_rrd->ptr);
return HANDLER_ERROR;
}
/* still create DB if it's empty file */
if (st.st_size > 0) {
return HANDLER_GO_ON;
}
}
/* create a new one */
buffer * const cmd = srv->tmp_buf;
buffer_copy_string_len(cmd, CONST_STR_LEN("create "));
buffer_append_string_buffer(cmd, s->path_rrd);
buffer_append_string_len(cmd, CONST_STR_LEN(
" --step 60 "
"DS:InOctets:ABSOLUTE:600:U:U "
"DS:OutOctets:ABSOLUTE:600:U:U "
"DS:Requests:ABSOLUTE:600:U:U "
"RRA:AVERAGE:0.5:1:600 "
"RRA:AVERAGE:0.5:6:700 "
"RRA:AVERAGE:0.5:24:775 "
"RRA:AVERAGE:0.5:288:797 "
"RRA:MAX:0.5:1:600 "
"RRA:MAX:0.5:6:700 "
"RRA:MAX:0.5:24:775 "
"RRA:MAX:0.5:288:797 "
"RRA:MIN:0.5:1:600 "
"RRA:MIN:0.5:6:700 "
"RRA:MIN:0.5:24:775 "
"RRA:MIN:0.5:288:797\n"));
if (-1 == (safe_write(p->write_fd, CONST_BUF_LEN(cmd)))) {
log_perror(srv->errh, __FILE__, __LINE__, "rrdtool-write: failed");
return HANDLER_ERROR;
}
if (-1 == safe_read(p->read_fd, resp, respsz)) {
log_perror(srv->errh, __FILE__, __LINE__, "rrdtool-read: failed");
return HANDLER_ERROR;
}
if (resp[0] != 'O' || resp[1] != 'K') {
log_error(srv->errh, __FILE__, __LINE__,
"rrdtool-response: %s %s", cmd->ptr, resp);
return HANDLER_ERROR;
}
return HANDLER_GO_ON;
}
__attribute_cold__
static int mod_rrd_fatal_error(plugin_data *p) {
/* future: might send kill() signal to p->rrdtool_pid to trigger restart */
p->rrdtool_running = 0;
return 0;
}
__attribute_noinline__
static int mod_rrd_write_data(server *srv, plugin_data *p, rrd_config *s) {
char resp[4096];
if (HANDLER_GO_ON != mod_rrdtool_create_rrd(srv, p, s, resp, sizeof(resp)))
return 0;
buffer * const cmd = srv->tmp_buf;
buffer_copy_string_len(cmd, CONST_STR_LEN("update "));
buffer_append_string_buffer(cmd, s->path_rrd);
buffer_append_string_len(cmd, CONST_STR_LEN(" N:"));
buffer_append_int(cmd, s->bytes_read);
buffer_append_string_len(cmd, CONST_STR_LEN(":"));
buffer_append_int(cmd, s->bytes_written);
buffer_append_string_len(cmd, CONST_STR_LEN(":"));
buffer_append_int(cmd, s->requests);
buffer_append_string_len(cmd, CONST_STR_LEN("\n"));
if (-1 == safe_write(p->write_fd, CONST_BUF_LEN(cmd))) {
log_error(srv->errh, __FILE__, __LINE__, "rrdtool-write: failed");
return mod_rrd_fatal_error(p);
}
if (-1 == safe_read(p->read_fd, resp, sizeof(resp))) {
log_error(srv->errh, __FILE__, __LINE__, "rrdtool-read: failed");
return mod_rrd_fatal_error(p);
}
if (resp[0] == 'O' && resp[1] == 'K') {
s->requests = 0;
s->bytes_written = 0;
s->bytes_read = 0;
}
else if (!(strstr(resp, "(minimum one second step)")
&& log_epoch_secs - srv->startup_ts < 3)) {
/* don't fail on this error if we just started (above condition)
* (graceful restart, the old one might have just updated too) */
log_error(srv->errh, __FILE__, __LINE__,
"rrdtool-response: %s %s", cmd->ptr, resp);
return mod_rrd_fatal_error(p);
}
return 1;
}
static void mod_rrd_write_data_loop(server *srv, plugin_data *p) {
/* process and validate config directives
* (init i to 0 if global context; to 1 to skip empty global context) */
for (int i = !p->cvlist[0].v.u2[1]; i < p->nconfig; ++i) {
config_plugin_value_t *cpv = p->cvlist + p->cvlist[i].v.u2[0];
for (; -1 != cpv->k_id; ++cpv) {
switch (cpv->k_id) {
case 0: /* rrdtool.db-name */
if (cpv->vtype != T_CONFIG_LOCAL) continue;
mod_rrd_write_data(srv, p, cpv->v.v);
if (!p->rrdtool_running) return;
break;
}
}
}
}
TRIGGER_FUNC(mod_rrd_trigger) {
plugin_data *p = p_d;
/*(0 == p->rrdtool_pid if never activated; not used)*/
if (0 == p->rrdtool_pid) return HANDLER_GO_ON;
/* write data once a minute */
if ((log_epoch_secs % 60) != 0) return HANDLER_GO_ON;
if (!p->rrdtool_running) {
if (srv->pid != p->srv_pid) return HANDLER_GO_ON;
/* restart limited to once every 60 sec (above) */
if (!mod_rrd_exec(srv, p)) return HANDLER_GO_ON;
}
mod_rrd_write_data_loop(srv, p);
return HANDLER_GO_ON;
}
static handler_t mod_rrd_waitpid_cb(server *srv, void *p_d, pid_t pid, int status) {
plugin_data *p = p_d;
if (pid != p->rrdtool_pid) return HANDLER_GO_ON;
if (srv->pid != p->srv_pid) return HANDLER_GO_ON;
p->rrdtool_running = 0;
p->rrdtool_pid = -1;
UNUSED(status);
return HANDLER_FINISHED;
}
REQUESTDONE_FUNC(mod_rrd_account) {
plugin_data *p = p_d;
/*(0 == p->rrdtool_pid if never activated; not used)*/
if (0 == p->rrdtool_pid) return HANDLER_GO_ON;
mod_rrd_patch_config(r, p);
rrd_config * const rrd = p->conf.rrd;
if (NULL == rrd) return HANDLER_GO_ON;
++rrd->requests;
if (r->http_version <= HTTP_VERSION_1_1) {
rrd->bytes_written += (r->con->bytes_written - r->bytes_written_ckpt);
rrd->bytes_read += (r->con->bytes_read - r->bytes_read_ckpt);
}
else {
rrd->bytes_written += r->write_queue.bytes_out;
rrd->bytes_read += r->read_queue.bytes_in;
}
return HANDLER_GO_ON;
}
int mod_rrdtool_plugin_init(plugin *p);
int mod_rrdtool_plugin_init(plugin *p) {
p->version = LIGHTTPD_VERSION_ID;
p->name = "rrd";
p->init = mod_rrd_init;
p->cleanup = mod_rrd_free;
p->set_defaults= mod_rrd_set_defaults;
p->handle_trigger = mod_rrd_trigger;
p->handle_waitpid = mod_rrd_waitpid_cb;
p->handle_request_done = mod_rrd_account;
return 0;
}
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