mpd/src/client.c

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/* the Music Player Daemon (MPD)
* Copyright (C) 2003-2007 by Warren Dukes (warren.dukes@gmail.com)
* This project's homepage is: http://www.musicpd.org
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include "client.h"
#include "command.h"
#include "conf.h"
#include "log.h"
#include "listen.h"
#include "permission.h"
#include "sllist.h"
#include "utils.h"
#include "ioops.h"
#include "main_notify.h"
#include "dlist.h"
#include "idle.h"
#include "../config.h"
#include <glib.h>
#include <assert.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <string.h>
#define GREETING "OK MPD " PROTOCOL_VERSION "\n"
#define CLIENT_LIST_MODE_BEGIN "command_list_begin"
#define CLIENT_LIST_OK_MODE_BEGIN "command_list_ok_begin"
#define CLIENT_LIST_MODE_END "command_list_end"
#define CLIENT_TIMEOUT_DEFAULT (60)
#define CLIENT_MAX_CONNECTIONS_DEFAULT (10)
#define CLIENT_MAX_COMMAND_LIST_DEFAULT (2048*1024)
#define CLIENT_MAX_OUTPUT_BUFFER_SIZE_DEFAULT (8192*1024)
/* set this to zero to indicate we have no possible clients */
static unsigned int client_max_connections; /*CLIENT_MAX_CONNECTIONS_DEFAULT; */
static int client_timeout = CLIENT_TIMEOUT_DEFAULT;
static size_t client_max_command_list_size =
CLIENT_MAX_COMMAND_LIST_DEFAULT;
static size_t client_max_output_buffer_size =
CLIENT_MAX_OUTPUT_BUFFER_SIZE_DEFAULT;
struct client {
struct list_head siblings;
char buffer[4096];
size_t bufferLength;
size_t bufferPos;
int fd; /* file descriptor; -1 if expired */
unsigned permission;
/** the uid of the client process, or -1 if unknown */
int uid;
time_t lastTime;
GSList *cmd_list; /* for when in list mode */
int cmd_list_OK; /* print OK after each command execution */
size_t cmd_list_size; /* mem cmd_list consumes */
struct sllnode *deferred_send; /* for output if client is slow */
size_t deferred_bytes; /* mem deferred_send consumes */
unsigned int num; /* client number */
char send_buf[4096];
size_t send_buf_used; /* bytes used this instance */
/** is this client waiting for an "idle" response? */
bool idle_waiting;
/** idle flags pending on this client, to be sent as soon as
the client enters "idle" */
unsigned idle_flags;
};
static LIST_HEAD(clients);
static unsigned num_clients;
static void client_write_deferred(struct client *client);
static void client_write_output(struct client *client);
int client_is_expired(const struct client *client)
{
return client->fd < 0;
}
int client_get_uid(const struct client *client)
{
return client->uid;
}
unsigned client_get_permission(const struct client *client)
{
return client->permission;
}
void client_set_permission(struct client *client, unsigned permission)
{
client->permission = permission;
}
static inline void client_set_expired(struct client *client)
{
if (client->fd >= 0) {
xclose(client->fd);
client->fd = -1;
}
}
static void client_init(struct client *client, int fd)
{
static unsigned int next_client_num;
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assert(fd >= 0);
client->cmd_list_size = 0;
client->cmd_list_OK = -1;
client->bufferLength = 0;
client->bufferPos = 0;
client->fd = fd;
set_nonblocking(fd);
client->lastTime = time(NULL);
client->cmd_list = NULL;
client->deferred_send = NULL;
client->deferred_bytes = 0;
client->num = next_client_num++;
client->send_buf_used = 0;
client->permission = getDefaultPermissions();
xwrite(fd, GREETING, strlen(GREETING));
}
static void free_cmd_list(GSList *list)
{
for (GSList *tmp = list; tmp != NULL; tmp = g_slist_next(tmp))
g_free(tmp->data);
g_slist_free(list);
}
static void new_cmd_list_ptr(struct client *client, char *s)
{
client->cmd_list = g_slist_prepend(client->cmd_list, g_strdup(s));
}
static void client_close(struct client *client)
{
struct sllnode *buf;
assert(num_clients > 0);
assert(!list_empty(&clients));
list_del(&client->siblings);
--num_clients;
client_set_expired(client);
if (client->cmd_list) {
free_cmd_list(client->cmd_list);
client->cmd_list = NULL;
}
if ((buf = client->deferred_send)) {
do {
struct sllnode *prev = buf;
buf = buf->next;
free(prev);
} while (buf);
client->deferred_send = NULL;
}
SECURE("client %i: closed\n", client->num);
free(client);
}
static const char *
sockaddr_to_tmp_string(const struct sockaddr *addr)
{
const char *hostname;
switch (addr->sa_family) {
#ifdef HAVE_TCP
case AF_INET:
hostname = (const char *)inet_ntoa(((const struct sockaddr_in *)
addr)->sin_addr);
if (!hostname)
hostname = "error getting ipv4 address";
break;
#ifdef HAVE_IPV6
case AF_INET6:
{
static char host[INET6_ADDRSTRLEN + 1];
memset(host, 0, INET6_ADDRSTRLEN + 1);
if (inet_ntop(AF_INET6, (const void *)
&(((const struct sockaddr_in6 *)addr)->
sin6_addr), host,
INET6_ADDRSTRLEN)) {
hostname = (const char *)host;
} else {
hostname = "error getting ipv6 address";
}
}
break;
#endif
#endif /* HAVE_TCP */
#ifdef HAVE_UN
case AF_UNIX:
hostname = "local connection";
break;
#endif /* HAVE_UN */
default:
hostname = "unknown";
}
return hostname;
}
void client_new(int fd, const struct sockaddr *addr, int uid)
{
struct client *client;
if (num_clients >= client_max_connections) {
ERROR("Max Connections Reached!\n");
xclose(fd);
return;
}
client = xcalloc(1, sizeof(*client));
list_add(&client->siblings, &clients);
++num_clients;
client_init(client, fd);
client->uid = uid;
SECURE("client %i: opened from %s\n", client->num,
sockaddr_to_tmp_string(addr));
}
static int client_process_line(struct client *client, char *line)
{
int ret = 1;
if (strcmp(line, "noidle") == 0) {
if (client->idle_waiting) {
/* send empty idle response and leave idle mode */
client->idle_waiting = false;
command_success(client);
client_write_output(client);
}
/* do nothing if the client wasn't idling: the client
has already received the full idle response from
client_idle_notify(), which he can now evaluate */
return 0;
} else if (client->idle_waiting) {
/* during idle mode, clients must not send anything
except "noidle" */
ERROR("client %i: command \"%s\" during idle\n",
client->num, line);
return COMMAND_RETURN_CLOSE;
}
if (client->cmd_list_OK >= 0) {
if (strcmp(line, CLIENT_LIST_MODE_END) == 0) {
DEBUG("client %i: process command "
"list\n", client->num);
/* for scalability reasons, we have prepended
each new command; now we have to reverse it
to restore the correct order */
client->cmd_list = g_slist_reverse(client->cmd_list);
ret = command_process_list(client,
client->cmd_list_OK,
client->cmd_list);
DEBUG("client %i: process command "
"list returned %i\n", client->num, ret);
if (ret == COMMAND_RETURN_CLOSE ||
client_is_expired(client))
return COMMAND_RETURN_CLOSE;
if (ret == 0)
command_success(client);
client_write_output(client);
free_cmd_list(client->cmd_list);
client->cmd_list = NULL;
client->cmd_list_OK = -1;
} else {
size_t len = strlen(line) + 1;
client->cmd_list_size += len;
if (client->cmd_list_size >
client_max_command_list_size) {
ERROR("client %i: command "
"list size (%lu) is "
"larger than the max "
"(%lu)\n",
client->num,
(unsigned long)client->cmd_list_size,
(unsigned long)
client_max_command_list_size);
return COMMAND_RETURN_CLOSE;
} else
new_cmd_list_ptr(client, line);
}
} else {
if (strcmp(line, CLIENT_LIST_MODE_BEGIN) == 0) {
client->cmd_list_OK = 0;
ret = 1;
} else if (strcmp(line, CLIENT_LIST_OK_MODE_BEGIN) == 0) {
client->cmd_list_OK = 1;
ret = 1;
} else {
DEBUG("client %i: process command \"%s\"\n",
client->num, line);
ret = command_process(client, line);
DEBUG("client %i: command returned %i\n",
client->num, ret);
if (ret == COMMAND_RETURN_CLOSE ||
client_is_expired(client))
return COMMAND_RETURN_CLOSE;
if (ret == 0)
command_success(client);
client_write_output(client);
}
}
return ret;
}
static int client_input_received(struct client *client, size_t bytesRead)
{
char *start = client->buffer + client->bufferPos, *end;
char *newline, *next;
int ret;
assert(client->bufferPos <= client->bufferLength);
assert(client->bufferLength + bytesRead <= sizeof(client->buffer));
client->bufferLength += bytesRead;
end = client->buffer + client->bufferLength;
/* process all lines */
while ((newline = memchr(start, '\n', end - start)) != NULL) {
next = newline + 1;
if (newline > start && newline[-1] == '\r')
--newline;
*newline = 0;
ret = client_process_line(client, start);
if (ret == COMMAND_RETURN_KILL ||
ret == COMMAND_RETURN_CLOSE)
return ret;
if (client_is_expired(client))
return COMMAND_RETURN_CLOSE;
start = next;
}
/* mark consumed lines */
client->bufferPos = start - client->buffer;
/* if we're have reached the buffer's end, close the gab at
the beginning */
if (client->bufferLength == sizeof(client->buffer)) {
if (client->bufferPos == 0) {
ERROR("client %i: buffer overflow\n",
client->num);
return COMMAND_RETURN_CLOSE;
}
assert(client->bufferLength >= client->bufferPos
&& "bufferLength >= bufferPos");
client->bufferLength -= client->bufferPos;
memmove(client->buffer,
client->buffer + client->bufferPos,
client->bufferLength);
client->bufferPos = 0;
}
return 0;
}
static int client_read(struct client *client)
{
ssize_t bytesRead;
assert(client->bufferPos <= client->bufferLength);
assert(client->bufferLength < sizeof(client->buffer));
bytesRead = read(client->fd,
client->buffer + client->bufferLength,
sizeof(client->buffer) - client->bufferLength);
if (bytesRead > 0)
return client_input_received(client, bytesRead);
else if (bytesRead < 0 && errno == EINTR)
/* try again later, after select() */
return 0;
else
/* peer disconnected or I/O error */
return COMMAND_RETURN_CLOSE;
}
static void client_manager_register_read_fd(fd_set * fds, int *fdmax)
{
struct client *client;
FD_ZERO(fds);
addListenSocketsToFdSet(fds, fdmax);
list_for_each_entry(client, &clients, siblings) {
if (!client_is_expired(client) && !client->deferred_send) {
FD_SET(client->fd, fds);
if (*fdmax < client->fd)
*fdmax = client->fd;
}
}
}
static void client_manager_register_write_fd(fd_set * fds, int *fdmax)
{
struct client *client;
FD_ZERO(fds);
list_for_each_entry(client, &clients, siblings) {
if (client->fd >= 0 && !client_is_expired(client)
&& client->deferred_send) {
FD_SET(client->fd, fds);
if (*fdmax < client->fd)
*fdmax = client->fd;
}
}
}
int client_manager_io(void)
{
fd_set rfds;
fd_set wfds;
fd_set efds;
struct client *client, *n;
int ret;
int fdmax = 0;
FD_ZERO( &efds );
client_manager_register_read_fd(&rfds, &fdmax);
client_manager_register_write_fd(&wfds, &fdmax);
registered_IO_add_fds(&fdmax, &rfds, &wfds, &efds);
main_notify_lock();
ret = select(fdmax + 1, &rfds, &wfds, &efds, NULL);
main_notify_unlock();
if (ret < 0) {
if (errno == EINTR)
return 0;
FATAL("select() failed: %s\n", strerror(errno));
}
registered_IO_consume_fds(&ret, &rfds, &wfds, &efds);
getConnections(&rfds);
list_for_each_entry_safe(client, n, &clients, siblings) {
if (FD_ISSET(client->fd, &rfds)) {
ret = client_read(client);
if (ret == COMMAND_RETURN_KILL)
return COMMAND_RETURN_KILL;
if (ret == COMMAND_RETURN_CLOSE) {
client_close(client);
continue;
}
assert(!client_is_expired(client));
client->lastTime = time(NULL);
}
if (!client_is_expired(client) &&
FD_ISSET(client->fd, &wfds)) {
client_write_deferred(client);
client->lastTime = time(NULL);
}
}
return 0;
}
void client_manager_init(void)
{
char *test;
ConfigParam *param;
param = getConfigParam(CONF_CONN_TIMEOUT);
if (param) {
client_timeout = strtol(param->value, &test, 10);
if (*test != '\0' || client_timeout <= 0) {
FATAL("connection timeout \"%s\" is not a positive "
"integer, line %i\n", CONF_CONN_TIMEOUT,
param->line);
}
}
param = getConfigParam(CONF_MAX_CONN);
if (param) {
client_max_connections = strtol(param->value, &test, 10);
if (*test != '\0' || client_max_connections <= 0) {
FATAL("max connections \"%s\" is not a positive integer"
", line %i\n", param->value, param->line);
}
} else
client_max_connections = CLIENT_MAX_CONNECTIONS_DEFAULT;
param = getConfigParam(CONF_MAX_COMMAND_LIST_SIZE);
if (param) {
long tmp = strtol(param->value, &test, 10);
if (*test != '\0' || tmp <= 0) {
FATAL("max command list size \"%s\" is not a positive "
"integer, line %i\n", param->value, param->line);
}
client_max_command_list_size = tmp * 1024;
}
param = getConfigParam(CONF_MAX_OUTPUT_BUFFER_SIZE);
if (param) {
long tmp = strtol(param->value, &test, 10);
if (*test != '\0' || tmp <= 0) {
FATAL("max output buffer size \"%s\" is not a positive "
"integer, line %i\n", param->value, param->line);
}
client_max_output_buffer_size = tmp * 1024;
}
}
static void client_close_all(void)
{
struct client *client, *n;
list_for_each_entry_safe(client, n, &clients, siblings)
client_close(client);
num_clients = 0;
}
void client_manager_deinit(void)
{
client_close_all();
client_max_connections = 0;
}
void client_manager_expire(void)
{
struct client *client, *n;
list_for_each_entry_safe(client, n, &clients, siblings) {
if (client_is_expired(client)) {
DEBUG("client %i: expired\n", client->num);
client_close(client);
} else if (!client->idle_waiting && /* idle clients
never expire */
time(NULL) - client->lastTime >
client_timeout) {
DEBUG("client %i: timeout\n", client->num);
client_close(client);
}
}
}
static void client_write_deferred(struct client *client)
{
struct sllnode *buf;
ssize_t ret = 0;
buf = client->deferred_send;
while (buf) {
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assert(buf->size > 0);
ret = write(client->fd, buf->data, buf->size);
if (ret < 0)
break;
else if ((size_t)ret < buf->size) {
assert(client->deferred_bytes >= (size_t)ret);
client->deferred_bytes -= ret;
buf->data = (char *)buf->data + ret;
buf->size -= ret;
} else {
struct sllnode *tmp = buf;
size_t decr = (buf->size + sizeof(struct sllnode));
assert(client->deferred_bytes >= decr);
client->deferred_bytes -= decr;
buf = buf->next;
free(tmp);
client->deferred_send = buf;
}
client->lastTime = time(NULL);
}
if (!client->deferred_send) {
DEBUG("client %i: buffer empty %lu\n", client->num,
(unsigned long)client->deferred_bytes);
assert(client->deferred_bytes == 0);
} else if (ret < 0 && errno != EAGAIN && errno != EINTR) {
/* cause client to close */
DEBUG("client %i: problems flushing buffer\n",
client->num);
client_set_expired(client);
}
}
static void client_defer_output(struct client *client,
const void *data, size_t length)
{
struct sllnode **buf_r;
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assert(length > 0);
client->deferred_bytes += sizeof(struct sllnode) + length;
if (client->deferred_bytes > client_max_output_buffer_size) {
ERROR("client %i: output buffer size (%lu) is "
"larger than the max (%lu)\n",
client->num,
(unsigned long)client->deferred_bytes,
(unsigned long)client_max_output_buffer_size);
/* cause client to close */
client_set_expired(client);
return;
}
buf_r = &client->deferred_send;
while (*buf_r != NULL)
buf_r = &(*buf_r)->next;
*buf_r = new_sllnode(data, length);
}
static void client_write_direct(struct client *client,
const char *data, size_t length)
{
ssize_t ret;
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assert(length > 0);
assert(client->deferred_send == NULL);
if ((ret = write(client->fd, data, length)) < 0) {
if (errno == EAGAIN || errno == EINTR) {
client_defer_output(client, data, length);
} else {
DEBUG("client %i: problems writing\n", client->num);
client_set_expired(client);
return;
}
} else if ((size_t)ret < client->send_buf_used) {
client_defer_output(client, data + ret, length - ret);
}
if (client->deferred_send)
DEBUG("client %i: buffer created\n", client->num);
}
static void client_write_output(struct client *client)
{
if (client_is_expired(client) || !client->send_buf_used)
return;
if (client->deferred_send != NULL)
client_defer_output(client, client->send_buf,
client->send_buf_used);
else
client_write_direct(client, client->send_buf,
client->send_buf_used);
client->send_buf_used = 0;
}
void client_write(struct client *client, const char *buffer, size_t buflen)
{
/* if the client is going to be closed, do nothing */
if (client_is_expired(client))
return;
while (buflen > 0 && !client_is_expired(client)) {
size_t copylen;
assert(client->send_buf_used < sizeof(client->send_buf));
copylen = sizeof(client->send_buf) - client->send_buf_used;
if (copylen > buflen)
copylen = buflen;
memcpy(client->send_buf + client->send_buf_used, buffer,
copylen);
buflen -= copylen;
client->send_buf_used += copylen;
buffer += copylen;
if (client->send_buf_used >= sizeof(client->send_buf))
client_write_output(client);
}
}
void client_puts(struct client *client, const char *s)
{
client_write(client, s, strlen(s));
}
void client_vprintf(struct client *client, const char *fmt, va_list args)
{
va_list tmp;
int length;
char *buffer;
va_copy(tmp, args);
length = vsnprintf(NULL, 0, fmt, tmp);
va_end(tmp);
if (length <= 0)
/* wtf.. */
return;
buffer = xmalloc(length + 1);
vsnprintf(buffer, length + 1, fmt, args);
client_write(client, buffer, length);
free(buffer);
}
mpd_fprintf void client_printf(struct client *client, const char *fmt, ...)
{
va_list args;
va_start(args, fmt);
client_vprintf(client, fmt, args);
va_end(args);
}
static const char *const idle_names[] = {
"database",
"stored_playlist",
"playlist",
"player",
"mixer",
"output",
"options",
};
/**
* Send "idle" response to this client.
*/
static void
client_idle_notify(struct client *client)
{
unsigned flags, i;
assert(client->idle_waiting);
assert(client->idle_flags != 0);
flags = client->idle_flags;
client->idle_flags = 0;
client->idle_waiting = false;
for (i = 0; i < sizeof(idle_names) / sizeof(idle_names[0]); ++i) {
assert(idle_names[i] != NULL);
if (flags & (1 << i))
client_printf(client, "changed: %s\n",
idle_names[i]);
}
client_puts(client, "OK\n");
client->lastTime = time(NULL);
}
void client_manager_idle_add(unsigned flags)
{
struct client *client;
assert(flags != 0);
list_for_each_entry(client, &clients, siblings) {
if (client_is_expired(client))
continue;
client->idle_flags |= flags;
if (client->idle_waiting) {
client_idle_notify(client);
client_write_output(client);
}
}
}
bool client_idle_wait(struct client *client)
{
assert(!client->idle_waiting);
client->idle_waiting = true;
if (client->idle_flags != 0) {
client_idle_notify(client);
return true;
} else
return false;
}