[lvm-devel] LVM2/daemons/common daemon-client.h daemon-ser ...
mornfall at sourceware.org
mornfall at sourceware.org
Tue Jun 14 02:34:19 UTC 2011
CVSROOT: /cvs/lvm2
Module name: LVM2
Changes by: mornfall at sourceware.org 2011-06-14 02:34:18
Modified files:
daemons/common : daemon-client.h daemon-server.c daemon-server.h
Added files:
daemons/common : daemon-client.c daemon-shared.c daemon-shared.h
Log message:
Common daemon code: Implement basic socket-based communication infrastructure
(both client and server side). The server handles each connection in a separate
thread.
Patches:
http://sourceware.org/cgi-bin/cvsweb.cgi/LVM2/daemons/common/daemon-client.c.diff?cvsroot=lvm2&r1=NONE&r2=1.1
http://sourceware.org/cgi-bin/cvsweb.cgi/LVM2/daemons/common/daemon-shared.c.diff?cvsroot=lvm2&r1=NONE&r2=1.1
http://sourceware.org/cgi-bin/cvsweb.cgi/LVM2/daemons/common/daemon-shared.h.diff?cvsroot=lvm2&r1=NONE&r2=1.1
http://sourceware.org/cgi-bin/cvsweb.cgi/LVM2/daemons/common/daemon-client.h.diff?cvsroot=lvm2&r1=1.2&r2=1.3
http://sourceware.org/cgi-bin/cvsweb.cgi/LVM2/daemons/common/daemon-server.c.diff?cvsroot=lvm2&r1=1.3&r2=1.4
http://sourceware.org/cgi-bin/cvsweb.cgi/LVM2/daemons/common/daemon-server.h.diff?cvsroot=lvm2&r1=1.4&r2=1.5
/cvs/lvm2/LVM2/daemons/common/daemon-client.c,v --> standard output
revision 1.1
--- LVM2/daemons/common/daemon-client.c
+++ - 2011-06-14 02:34:19.031404000 +0000
@@ -0,0 +1,54 @@
+#include "daemon-client.h"
+#include "daemon-shared.h"
+#include <sys/un.h>
+#include <sys/socket.h>
+#include <string.h>
+#include <stdio.h>
+#include <assert.h>
+
+daemon_handle daemon_open(daemon_info i) {
+ daemon_handle h;
+ struct sockaddr_un sockaddr;
+ if ((h.socket_fd = socket(PF_UNIX, SOCK_STREAM | SOCK_NONBLOCK, 0)) < 0) {
+ perror("socket");
+ goto error;
+ }
+ memset(&sockaddr, 0, sizeof(sockaddr));
+ fprintf(stderr, "connecting to %s\n", i.socket);
+ strcpy(sockaddr.sun_path, i.socket);
+ sockaddr.sun_family = AF_UNIX;
+ if (connect(h.socket_fd,(struct sockaddr *) &sockaddr, sizeof(sockaddr))) {
+ perror("connect");
+ goto error;
+ }
+ h.protocol = 0;
+ return h;
+error:
+ if (h.socket_fd >= 0)
+ close(h.socket_fd);
+ h.socket_fd = -1;
+ return h;
+}
+
+daemon_reply daemon_send(daemon_handle h, daemon_request rq)
+{
+ daemon_reply reply;
+ assert(h.socket_fd >= 0);
+
+ if (!rq.buffer) {
+ /* TODO: build the buffer from rq.cft */
+ }
+
+ assert(rq.buffer);
+ write_buffer(h.socket_fd, rq.buffer, strlen(rq.buffer));
+
+ if (read_buffer(h.socket_fd, &reply.buffer)) {
+ /* TODO: parse reply.buffer into reply.cft */
+ } else
+ reply.error = 1;
+
+ return reply;
+}
+
+void daemon_close(daemon_handle h) {
+}
/cvs/lvm2/LVM2/daemons/common/daemon-shared.c,v --> standard output
revision 1.1
--- LVM2/daemons/common/daemon-shared.c
+++ - 2011-06-14 02:34:19.142467000 +0000
@@ -0,0 +1,68 @@
+#include <errno.h>
+#include <stdio.h>
+#include <malloc.h>
+#include <string.h>
+
+/*
+ * Read a single message from a (socket) filedescriptor. Messages are delimited
+ * by blank lines. This call will block until all of a message is received. The
+ * memory will be allocated from heap. Upon error, all memory is freed and the
+ * buffer pointer is set to NULL.
+ */
+int read_buffer(int fd, char **buffer) {
+ int bytes = 0;
+ int buffersize = 32;
+ *buffer = malloc(buffersize + 1);
+
+ while (1) {
+ int result = read(fd, (*buffer) + bytes, buffersize - bytes);
+ if (result > 0)
+ bytes += result;
+ if (result == 0)
+ goto fail; /* we should never encounter EOF here */
+ if (result < 0 && errno != EAGAIN && errno != EWOULDBLOCK)
+ goto fail;
+
+ if (bytes == buffersize) {
+ buffersize += 1024;
+ char *new = realloc(*buffer, buffersize + 1);
+ if (new)
+ *buffer = new;
+ else
+ goto fail;
+ } else {
+ (*buffer)[bytes] = 0;
+ char *end;
+ if ((end = strstr((*buffer) + bytes - 2, "\n\n"))) {
+ *end = 0;
+ break; /* success, we have the full message now */
+ }
+ /* TODO call select here if we encountered EAGAIN/EWOULDBLOCK */
+ }
+ }
+ return 1;
+fail:
+ free(*buffer);
+ *buffer = NULL;
+ return 0;
+}
+
+/*
+ * Write a buffer to a filedescriptor. Keep trying. Blocks (even on
+ * SOCK_NONBLOCK) until all of the write went through.
+ *
+ * TODO use select on EWOULDBLOCK/EAGAIN to avoid useless spinning
+ */
+int write_buffer(int fd, char *buffer, int length) {
+ int written = 0;
+ while (1) {
+ int result = write(fd, buffer + written, length - written);
+ if (result > 0)
+ written += result;
+ if (result < 0 && errno != EWOULDBLOCK && errno != EAGAIN)
+ break; /* too bad */
+ if (written == length)
+ return 1; /* done */
+ }
+ return 0;
+}
/cvs/lvm2/LVM2/daemons/common/daemon-shared.h,v --> standard output
revision 1.1
--- LVM2/daemons/common/daemon-shared.h
+++ - 2011-06-14 02:34:19.240114000 +0000
@@ -0,0 +1,2 @@
+int read_buffer(int fd, char **buffer);
+int write_buffer(int fd, char *buffer, int length);
--- LVM2/daemons/common/daemon-client.h 2011/05/15 11:02:29 1.2
+++ LVM2/daemons/common/daemon-client.h 2011/06/14 02:34:18 1.3
@@ -12,6 +12,8 @@
* Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
+#include "config.h" // should become part of libdevmapper later
+
#ifndef _LVM_DAEMON_COMMON_CLIENT_H
#define _LVM_DAEMON_COMMON_CLIENT_H
@@ -28,13 +30,14 @@
} daemon_info;
typedef struct {
- char *request;
+ char *buffer;
+ struct config_node *cft;
} daemon_request;
typedef struct {
int error; /* 0 for success */
- char *reply; /* textual reply */
- struct config_tree *cft; /* parsed reply, if available */
+ char *buffer; /* textual reply */
+ struct config_node *cft; /* parsed reply, if available */
} daemon_reply;
/*
--- LVM2/daemons/common/daemon-server.c 2011/05/15 11:02:29 1.3
+++ LVM2/daemons/common/daemon-server.c 2011/06/14 02:34:18 1.4
@@ -107,8 +107,9 @@
fprintf(stderr, "setting CLOEXEC on socket fd %d failed: %s\n", fd, strerror(errno));
fcntl(fd, F_SETFL, fcntl(fd, F_GETFL, 0) | O_NONBLOCK);
+ fprintf(stderr, "creating %s\n", s.socket_path);
memset(&sockaddr, 0, sizeof(sockaddr));
- memcpy(sockaddr.sun_path, s.socket_path, strlen(s.socket_path));
+ strcpy(sockaddr.sun_path, s.socket_path);
sockaddr.sun_family = AF_UNIX;
if (bind(fd, (struct sockaddr *) &sockaddr, sizeof(sockaddr))) {
@@ -128,6 +129,7 @@
error:
if (fd >= 0) {
close(fd);
+ unlink(s.socket_path);
fd = -1;
}
goto out;
@@ -198,6 +200,60 @@
setsid();
}
+struct thread_baton {
+ daemon_state s;
+ client_handle client;
+};
+
+void *client_thread(void *baton)
+{
+ struct thread_baton *b = baton;
+ request req;
+ while (1) {
+ if (!read_buffer(b->client.socket_fd, &req.buffer))
+ goto fail;
+
+ /* TODO parse the buffer into req.cft */
+ response res = b->s.handler(b->s, b->client, req);
+
+ if (!res.buffer) {
+ /* TODO fill in the buffer from res.cft */
+ }
+
+ write_buffer(b->client.socket_fd, res.buffer, strlen(res.buffer));
+
+ free(res.buffer);
+ free(req.buffer);
+ }
+fail:
+ /* TODO what should we really do here? */
+ return NULL;
+}
+
+int handle_connect(daemon_state s)
+{
+ struct sockaddr_un sockaddr;
+ client_handle client;
+ socklen_t sl = sizeof(sockaddr);
+ int client_fd = accept(s.socket_fd, (struct sockaddr *) &sockaddr, &sl);
+ if (client_fd < 0)
+ return 0;
+
+ struct thread_baton *baton = malloc(sizeof(struct thread_baton));
+ if (!baton)
+ return 0;
+
+ client.socket_fd = client_fd;
+ client.read_buf = 0;
+ client.private = 0;
+ baton->s = s;
+ baton->client = client;
+
+ if (pthread_create(&baton->client.thread_id, NULL, client_thread, baton))
+ return 0;
+ return 1;
+}
+
void daemon_start(daemon_state s)
{
int failed = 0;
@@ -230,6 +286,8 @@
signal(SIGINT, &_exit_handler);
signal(SIGHUP, &_exit_handler);
signal(SIGQUIT, &_exit_handler);
+ signal(SIGTERM, &_exit_handler);
+ signal(SIGPIPE, SIG_IGN);
#ifdef linux
if (s.avoid_oom && !_set_oom_adj(OOM_DISABLE) && !_set_oom_adj(OOM_ADJUST_MIN))
@@ -247,9 +305,20 @@
kill(getppid(), SIGTERM);
while (!_shutdown_requested && !failed) {
- /* TODO: do work */
+ int status;
+ fd_set in;
+ FD_ZERO(&in);
+ FD_SET(s.socket_fd, &in);
+ if (select(FD_SETSIZE, &in, NULL, NULL, NULL) < 0 && errno != EINTR)
+ perror("select error");
+ if (FD_ISSET(s.socket_fd, &in))
+ if (!handle_connect(s))
+ syslog(LOG_ERR, "Failed to handle a client connection.");
}
+ if (s.socket_fd >= 0)
+ unlink(s.socket_path);
+
syslog(LOG_NOTICE, "%s shutting down", s.name);
closelog();
remove_lockfile(s.pidfile);
--- LVM2/daemons/common/daemon-server.h 2011/05/15 11:02:29 1.4
+++ LVM2/daemons/common/daemon-server.h 2011/06/14 02:34:18 1.5
@@ -13,6 +13,7 @@
*/
#include "daemon-client.h"
+#include "config.h" // XXX will be in libdevmapper.h later
#ifndef _LVM_DAEMON_COMMON_SERVER_H
#define _LVM_DAEMON_COMMON_SERVER_H
@@ -25,12 +26,14 @@
} client_handle;
typedef struct {
- struct config_tree *cft;
+ struct config_node *cft;
+ char *buffer;
} request;
typedef struct {
int error;
- struct config_tree *cft;
+ struct config_node *cft;
+ char *buffer;
} response;
struct daemon_state;
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