[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [PATCH 03/29] tools/xenlogd: connect to frontend
Add the code for connecting to frontends to xenlogd. Signed-off-by: Juergen Gross <jgross@xxxxxxxx> --- tools/xenlogd/Makefile | 2 +- tools/xenlogd/io.c | 45 ++++ tools/xenlogd/xenlogd.c | 575 +++++++++++++++++++++++++++++++++++++++- tools/xenlogd/xenlogd.h | 50 ++++ 4 files changed, 668 insertions(+), 4 deletions(-) create mode 100644 tools/xenlogd/io.c create mode 100644 tools/xenlogd/xenlogd.h diff --git a/tools/xenlogd/Makefile b/tools/xenlogd/Makefile index 550e914f59..0d44cd0e85 100644 --- a/tools/xenlogd/Makefile +++ b/tools/xenlogd/Makefile @@ -10,7 +10,7 @@ LDFLAGS += $(PTHREAD_LDFLAGS) TARGETS := xenlogd -XENLOGD_OBJS = xenlogd.o +XENLOGD_OBJS = xenlogd.o io.o $(XENLOGD_OBJS): CFLAGS += $(CFLAGS_libxenstore) $(XENLOGD_OBJS): CFLAGS += $(CFLAGS_libxenevtchn) $(XENLOGD_OBJS): CFLAGS += $(CFLAGS_libxengnttab) diff --git a/tools/xenlogd/io.c b/tools/xenlogd/io.c new file mode 100644 index 0000000000..ef0954d69d --- /dev/null +++ b/tools/xenlogd/io.c @@ -0,0 +1,45 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +/* + * xenlogd - Xen logging daemon + * + * Copyright (C) 2023 Juergen Gross <jgross@xxxxxxxx> + * + * I/O thread handling. + */ + +#include <stdbool.h> +#include <string.h> +#include <syslog.h> + +#include "xenlogd.h" + +static bool io_work_pending(device *device) +{ + if ( device->stop_thread ) + return true; + return false; +} + +void *io_thread(void *arg) +{ + device *device = arg; + + while ( !device->stop_thread ) + { + pthread_mutex_lock(&device->mutex); + if ( !io_work_pending(device) ) + { + if ( xenevtchn_unmask(xe, device->evtchn) < 0 ) + syslog(LOG_WARNING, "xenevtchn_unmask() failed"); + pthread_cond_wait(&device->cond, &device->mutex); + } + pthread_mutex_unlock(&device->mutex); + + /* TODO: I/O handling. */ + } + + device->thread_active = false; + + return NULL; +} diff --git a/tools/xenlogd/xenlogd.c b/tools/xenlogd/xenlogd.c index 792d1026a3..da0a09a122 100644 --- a/tools/xenlogd/xenlogd.c +++ b/tools/xenlogd/xenlogd.c @@ -24,34 +24,562 @@ #include <err.h> #include <errno.h> +#include <poll.h> +#include <pthread.h> #include <signal.h> #include <stdbool.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #include <syslog.h> +#include <sys/mman.h> #include <sys/types.h> #include <sys/stat.h> #include <unistd.h> -#include <xenevtchn.h> #include <xengnttab.h> #include <xenstore.h> +#include "xenlogd.h" + +/* + * List of currently known devices. + * The list itself is modified only in the main thread. When a device is being + * removed its memory needs to be freed after the I/O thread (if existing) + * has stopped. + */ +static XEN_TAILQ_HEAD(devhead, device) devs = XEN_TAILQ_HEAD_INITIALIZER(devs); + +struct path { + char path[100]; +}; + static bool stop_me; static bool daemon_running; static struct xs_handle *xs; static xengnttab_handle *xg; -static xenevtchn_handle *xe; +static unsigned int now; + +xenevtchn_handle *xe; static void handle_stop(int sig) { stop_me = true; } +static int check_host_path(device *device) +{ + struct stat statbuf; + char *path, *p; + int ret = 1; + + if ( !device->host_path ) + return 1; + + if ( device->host_path[0] != '/' ) + return 1; + + path = strdup(device->host_path); + if ( !path ) + { + syslog(LOG_CRIT, "memory allocation failure!"); + return 1; + } + + for ( p = path; p; ) + { + p = strchr(p + 1, '/'); + if ( p ) + *p = 0; + if ( !stat(path, &statbuf) ) + { + if ( !(statbuf.st_mode & S_IFDIR) ) + break; + if ( !p ) + { + ret = 0; + break; + } + *p = '/'; + continue; + } + if ( mkdir(path, 0777) ) + break; + if ( p ) + *p = '/'; + } + + free(path); + return ret; +} + +static void construct_frontend_path(device *device, const char *node, + struct path *p) +{ + snprintf(p->path, sizeof(p->path), "/local/domain/%u/device/9pfs/%u/%s", + device->domid, device->devid, node); +} + +static void construct_backend_path(device *device, const char *node, + struct path *p) +{ + snprintf(p->path, sizeof(p->path), "backend/xen_9pfs/%u/%u/%s", + device->domid, device->devid, node); +} + +static char *read_backend_node(device *device, const char *node) +{ + struct path p; + char *val; + unsigned int len; + + construct_backend_path(device, node, &p); + val = xs_read(xs, XBT_NULL, p.path, &len); + + return val; +} + +static unsigned int uint_from_string(char *string, unsigned int def) +{ + unsigned long val; + char *end; + + if ( !string ) + return def; + + val = strtoul(string, &end, 10); + if ( *end || val > UINT_MAX ) + val = def; + free(string); + + return val; +} + +static unsigned int read_backend_node_uint(device *device, const char *node, + unsigned int def) +{ + return uint_from_string(read_backend_node(device, node), def); +} + +static unsigned int read_frontend_node_uint(device *device, const char *node, + unsigned int def) +{ + struct path p; + unsigned int len; + + construct_frontend_path(device, node, &p); + + return uint_from_string(xs_read(xs, XBT_NULL, p.path, &len), def); +} + +static int write_backend_node(device *device, const char *node, const char *val) +{ + struct path p; + struct xs_permissions perms[2] = { + { .id = 0, .perms = XS_PERM_NONE }, + { .id = device->domid, .perms = XS_PERM_READ } + }; + + construct_backend_path(device, node, &p); + if ( !xs_write(xs, XBT_NULL, p.path, val, strlen(val)) ) + { + syslog(LOG_ERR, "error writing bacḱend node \"%s\" for device %u/%u", + node, device->domid, device->devid); + return 1; + } + + if ( !xs_set_permissions(xs, XBT_NULL, p.path, perms, 2) ) + { + syslog(LOG_ERR, "error setting permissions for \"%s\"", p.path); + return 1; + } + + return 0; +} + +static int write_backend_state(device *device, enum xenbus_state state) +{ + struct path p; + char val[2]; + + snprintf(val, sizeof(val), "%u", state); + construct_backend_path(device, "state", &p); + if ( !xs_write(xs, XBT_NULL, p.path, val, 1) ) + { + syslog(LOG_ERR, "error writing backend state %u for device %u/%u", + state, device->domid, device->devid); + return 1; + } + + device->backend_state = state; + + return 0; +} + +static device *find_device(unsigned int domid, unsigned int devid) +{ + device *device; + + XEN_TAILQ_FOREACH( device, &devs, list ) + { + if ( domid == device->domid && devid == device->devid ) + return device; + } + + return NULL; +} + +static void free_device(device *device) +{ + char token[20]; + struct path p; + + construct_frontend_path(device, "state", &p); + snprintf(token, sizeof(token), "%u/%u", device->domid, device->devid); + xs_unwatch(xs, p.path, token); + + free(device->host_path); + + pthread_mutex_destroy(&device->mutex); + pthread_cond_destroy(&device->cond); + + free(device); +} + +static device *new_device(unsigned int domid, unsigned int devid) +{ + device *device; + char token[20]; + struct path p; + char *val; + + device = calloc(1, sizeof(*device)); + if ( !device ) + { + syslog(LOG_CRIT, "Got no memory for new device %u/%u", domid, devid); + return NULL; + } + + device->domid = domid; + device->devid = devid; + + construct_frontend_path(device, "state", &p); + snprintf(token, sizeof(token), "%u/%u", domid, devid); + if ( !xs_watch(xs, p.path, token) ) + { + syslog(LOG_ERR, "Setting up watch for device %u/%u failed", + domid, devid); + free(device); + return NULL; + } + + pthread_cond_init(&device->cond, NULL); + pthread_mutex_init(&device->mutex, NULL); + + val = read_backend_node(device, "security_model"); + if ( !val || strcmp(val, "none") ) + { + syslog(LOG_ERR, "Security model \"%s\" for device %u/%u invalid.", + val, domid, devid); + free(val); + goto err; + } + free(val); + + device->max_space = read_backend_node_uint(device, "max-space", 0); + device->max_files = read_backend_node_uint(device, "max-files", 0); + device->max_open_files = + read_backend_node_uint(device, "max-open-files", 0) + ?: MAX_OPEN_FILES_DEFAULT; + device->auto_delete = !!read_backend_node_uint(device, "auto-delete", 0); + + device->host_path = read_backend_node(device, "path"); + if ( check_host_path(device) ) + { + syslog(LOG_ERR, "Host path \"%s\" for device %u/%u invalid.", + device->host_path, domid, devid); + goto err; + } + + if ( write_backend_node(device, "versions", "1") ) + goto err; + if ( write_backend_node(device, "max-rings", "1") ) + goto err; + if ( write_backend_node(device, "max-ring-page-order", "9") ) + goto err; + + if ( write_backend_state(device, XenbusStateInitWait) ) + goto err; + + XEN_TAILQ_INSERT_TAIL(&devs, device, list); + syslog(LOG_INFO, "New device %u/%u added", domid, devid); + + return device; + + err: + free_device(device); + return NULL; +} + +static void disconnect_guest(device *device) +{ + if ( device->thread_active ) + { + device->stop_thread = true; + pthread_cond_signal(&device->cond); + pthread_join(device->thread, NULL); + device->stop_thread = false; + } + + if ( device->data.in ) + { + xengnttab_unmap(xg, device->data.in, 1 << device->ring_order); + device->data.in = NULL; + } + if ( device->intf ) + { + xengnttab_unmap(xg, device->intf, 1 ); + device->intf = NULL; + } + + if ( device->evtchn ) + { + xenevtchn_unbind(xe, device->evtchn); + device->evtchn = 0; + } +} + +static void close_device(device *device, enum xenbus_state state) +{ + disconnect_guest(device); + write_backend_state(device, state); +} + +static void connect_err(device *device, const char *msg) +{ + syslog(LOG_WARNING, "%s", msg); + close_device(device, XenbusStateClosed); +} + +static void connect_device(device *device) +{ + unsigned int val; + xenevtchn_port_or_error_t evtchn; + + val = read_frontend_node_uint(device, "version", 0); + if ( val != 1 ) + return connect_err(device, "frontend specifies illegal version"); + val = read_frontend_node_uint(device, "num-rings", 0); + if ( val != 1 ) + return connect_err(device, "frontend specifies illegal ring number"); + + val = read_frontend_node_uint(device, "event-channel-0", 0); + if ( val == 0 ) + return connect_err(device, "frontend specifies illegal evtchn"); + evtchn = xenevtchn_bind_interdomain(xe, device->domid, val); + if ( evtchn < 0 ) + return connect_err(device, "could not bind to event channel"); + device->evtchn = evtchn; + + val = read_frontend_node_uint(device, "ring-ref0", 0); + if ( val == 0 ) + return connect_err(device, "frontend specifies illegal grant for ring"); + device->intf = xengnttab_map_grant_ref(xg, device->domid, val, + PROT_READ | PROT_WRITE); + if ( !device->intf ) + return connect_err(device, "could not map interface page"); + device->ring_order = device->intf->ring_order; + if ( device->ring_order > 9 || device->ring_order < 1 ) + return connect_err(device, "frontend specifies illegal ring order"); + device->ring_size = XEN_FLEX_RING_SIZE(device->ring_order); + device->data.in = xengnttab_map_domain_grant_refs(xg, + 1 << device->ring_order, + device->domid, + device->intf->ref, + PROT_READ | PROT_WRITE); + if ( !device->data.in ) + return connect_err(device, "could not map ring pages"); + device->data.out = device->data.in + device->ring_size; + + if ( pthread_create(&device->thread, NULL, io_thread, device) ) + return connect_err(device, "could not start I/O thread"); + device->thread_active = true; + + write_backend_state(device, XenbusStateConnected); +} + +static void remove_device(device *device) +{ + XEN_TAILQ_REMOVE(&devs, device, list); + + disconnect_guest(device); + free_device(device); +} + +static void remove_all_devices(void) +{ + device *device, *tmp; + + XEN_TAILQ_FOREACH_SAFE( device, &devs, list, tmp ) + remove_device(device); +} + +static void frontend_changed(device *device) +{ + struct path p; + char *state, *end; + unsigned int len; + unsigned long new_state; + + construct_frontend_path(device, "state", &p); + state = xs_read(xs, XBT_NULL, p.path, &len); + if ( !state ) + { + close_device(device, XenbusStateClosed); + return; + } + + new_state = strtoul(state, &end, 10); + if ( *end || new_state > XenbusStateReconfigured ) + { + syslog(LOG_WARNING, "unknown state \"%s\" seen for device %u/%u", state, + device->domid, device->devid); + new_state = XenbusStateUnknown; + } + free(state); + + if ( new_state == device->frontend_state ) + return; + + switch ( new_state ) + { + case XenbusStateInitialising: + break; + + case XenbusStateInitialised: + connect_device(device); + break; + + case XenbusStateConnected: + break; + + case XenbusStateClosing: + close_device(device, XenbusStateClosing); + break; + + case XenbusStateClosed: + close_device(device, XenbusStateClosed); + break; + + default: + syslog(LOG_WARNING, "not handled frontend state %lu for device %u/%u", + new_state, device->domid, device->devid); + break; + } + + device->frontend_state = new_state; +} + +static void check_device(unsigned int domid, unsigned int devid) +{ + device *device; + + device = find_device(domid, devid); + if ( !device ) + { + device = new_device(domid, devid); + if ( !device ) + return; + } + + device->last_seen = now; +} + +static void scan_backend(void) +{ + char **doms; + unsigned int n_doms, dom; + char **devices; + unsigned int n_devs, dev; + char dom_path[24]; + unsigned long domid, devid; + char *end; + device *device, *tmp; + + now++; + + doms = xs_directory(xs, XBT_NULL, "backend/xen_9pfs", &n_doms); + if ( doms == NULL ) + return; + + for ( dom = 0; dom < n_doms; dom++ ) + { + errno = 0; + domid = strtoul(doms[dom], &end, 10); + if ( errno || *end || domid >= DOMID_FIRST_RESERVED ) + continue; + + snprintf(dom_path, sizeof(dom_path), "backend/xen_9pfs/%lu", domid); + devices = xs_directory(xs, XBT_NULL, dom_path, &n_devs); + + for ( dev = 0; dev < n_devs; dev++ ) + { + errno = 0; + devid = strtoul(devices[dev], &end, 10); + if ( errno || *end || devid > UINT_MAX ) + continue; + + check_device(domid, devid); + } + + free(devices); + } + + free(doms); + + XEN_TAILQ_FOREACH_SAFE( device, &devs, list, tmp ) + { + if ( device->last_seen != now ) + remove_device(device); + } +} + +static void handle_watch(char *path, char *token) +{ + unsigned int domid, devid; + device *device; + + if ( !strcmp(token, "main") ) + { + scan_backend(); + return; + } + + if ( sscanf(token, "%u/%u", &domid, &devid) != 2 ) + { + syslog(LOG_WARNING, "unknown watch event %s %s", path, token); + return; + } + + device = find_device(domid, devid); + if ( !device ) + { + syslog(LOG_WARNING, "watch event for unknown device %u/%u", + domid, devid); + return; + } + + frontend_changed(device); +} + static void close_all(void) { if ( daemon_running ) + { xs_rm(xs, XBT_NULL, "/tool/xenlog"); + xs_unwatch(xs, "backend/xen_9pfs", "main"); + + remove_all_devices(); + } if ( xe ) xenevtchn_close(xe); if ( xg ) @@ -68,6 +596,25 @@ static void do_err(const char *msg) exit(1); } +static void handle_event(void) +{ + xenevtchn_port_or_error_t evtchn; + device *device; + + evtchn = xenevtchn_pending(xe); + if ( evtchn < 0 ) + do_err("xenevtchn_pending() failed"); + + XEN_TAILQ_FOREACH( device, &devs, list ) + { + if ( device->evtchn == evtchn ) + { + pthread_cond_signal(&device->cond); + break; + } + } +} + static void xen_connect(void) { xs_transaction_t t; @@ -122,6 +669,11 @@ int main(int argc, char *argv[]) int syslog_mask = LOG_MASK(LOG_WARNING) | LOG_MASK(LOG_ERR) | LOG_MASK(LOG_CRIT) | LOG_MASK(LOG_ALERT) | LOG_MASK(LOG_EMERG); + char **watch; + struct pollfd p[2] = { + { .events = POLLIN, .revents = POLLIN }, + { .events = POLLIN } + }; umask(027); if ( getenv("XENLOGD_VERBOSE") ) @@ -134,9 +686,26 @@ int main(int argc, char *argv[]) xen_connect(); + if ( !xs_watch(xs, "backend/xen_9pfs", "main") ) + do_err("xs_watch() in main thread failed"); + p[0].fd = xs_fileno(xs); + p[1].fd = xenevtchn_fd(xe); + + scan_backend(); + while ( !stop_me ) { - sleep(60); + while ( (p[0].revents & POLLIN) && + (watch = xs_check_watch(xs)) != NULL ) + { + handle_watch(watch[XS_WATCH_PATH], watch[XS_WATCH_TOKEN]); + free(watch); + } + + if ( p[1].revents & POLLIN ) + handle_event(); + + poll(p, 2, 10000); } close_all(); diff --git a/tools/xenlogd/xenlogd.h b/tools/xenlogd/xenlogd.h new file mode 100644 index 0000000000..a8e9f9ca22 --- /dev/null +++ b/tools/xenlogd/xenlogd.h @@ -0,0 +1,50 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +#ifndef XENLOGD_H +#define XENLOGD_H + +#include <pthread.h> +#include <stdbool.h> +#include <xenevtchn.h> +#include <xen_list.h> +#include <xen/xen.h> +#include <xen/io/xenbus.h> +#include <xen/io/9pfs.h> + +#define MAX_OPEN_FILES_DEFAULT 5 + +typedef struct device device; +struct device { + /* Admin data. */ + XEN_TAILQ_ENTRY(device) list; + unsigned int last_seen; /* Set in scan_backend(). */ + unsigned int domid; + unsigned int devid; + bool thread_active; + bool stop_thread; + pthread_t thread; + pthread_cond_t cond; + pthread_mutex_t mutex; + + /* Tool side configuration data. */ + char *host_path; + unsigned int max_space; + unsigned int max_files; + unsigned int max_open_files; + bool auto_delete; + + /* Connection data. */ + enum xenbus_state backend_state; + enum xenbus_state frontend_state; + evtchn_port_t evtchn; + struct xen_9pfs_data_intf *intf; + unsigned int ring_order; + RING_IDX ring_size; + struct xen_9pfs_data data; +}; + +extern xenevtchn_handle *xe; + +void *io_thread(void *arg); + +#endif /* XENLOGD_H */ -- 2.35.3
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