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a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1708002322; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=2rcpEbJbgUxiNrBORk+pKJOPpR9mCjteYZqR1AIlbbY=; b=C8T/0ZV4tO8ots6sBRqict1+jS/oEW9uW0uVKX2Gza3KmZ7iyEg4IUZLoeELdrbaghnxhE tZg4AEERJOzCnEN2+ilRHJ2/ITxjACl0TQoiIv/jF80lHYHFa9leXUilFQLavlgUasISkn dWI74THZOzdvBnVuaOanhmfJqTcUCuM= From: Juergen Gross To: xen-devel@lists.xenproject.org Cc: Juergen Gross , Wei Liu , Anthony PERARD , Jason Andryuk Subject: [PATCH v7 02/21] tools/xen-9pfsd: connect to frontend Date: Thu, 15 Feb 2024 14:04:50 +0100 Message-Id: <20240215130509.24008-3-jgross@suse.com> X-Mailer: git-send-email 2.35.3 In-Reply-To: <20240215130509.24008-1-jgross@suse.com> References: <20240215130509.24008-1-jgross@suse.com> MIME-Version: 1.0 Authentication-Results: smtp-out1.suse.de; none X-Spamd-Result: default: False [-2.10 / 50.00]; ARC_NA(0.00)[]; RCVD_VIA_SMTP_AUTH(0.00)[]; FROM_HAS_DN(0.00)[]; TO_DN_SOME(0.00)[]; FREEMAIL_ENVRCPT(0.00)[gmail.com]; TO_MATCH_ENVRCPT_ALL(0.00)[]; MIME_GOOD(-0.10)[text/plain]; RCPT_COUNT_FIVE(0.00)[5]; RCVD_COUNT_THREE(0.00)[3]; DKIM_SIGNED(0.00)[suse.com:s=susede1]; MID_CONTAINS_FROM(1.00)[]; DBL_BLOCKED_OPENRESOLVER(0.00)[suse.com:email]; FUZZY_BLOCKED(0.00)[rspamd.com]; FROM_EQ_ENVFROM(0.00)[]; MIME_TRACE(0.00)[0:+]; FREEMAIL_CC(0.00)[suse.com,xen.org,citrix.com,gmail.com]; RCVD_TLS_ALL(0.00)[]; BAYES_HAM(-3.00)[100.00%] Add the code for connecting to frontends to xenlogd. Signed-off-by: Juergen Gross Acked-by: Anthony PERARD Reviewed-by: Jason Andryuk --- V2: - support multiple rings per device (Jason Andryuk) - don't set .revents initially (Jason Andryuk) - call poll() with infinite timeout (Jason Andryuk) - take mutex before calling pthread_cond_signal() V3: - fix SPDX indentifier (Andrew Cooper) - better validation of host path (Jason Andryuk) - don't hard-code dom0 in backend nodes (Jason Andryuk) - use bool instead of int for some functions' return types - open root directory (Jason Andryuk) --- tools/9pfsd/Makefile | 2 +- tools/9pfsd/io.c | 45 +++ tools/9pfsd/xen-9pfsd.c | 653 +++++++++++++++++++++++++++++++++++++++- tools/9pfsd/xen-9pfsd.h | 61 ++++ 4 files changed, 757 insertions(+), 4 deletions(-) create mode 100644 tools/9pfsd/io.c create mode 100644 tools/9pfsd/xen-9pfsd.h diff --git a/tools/9pfsd/Makefile b/tools/9pfsd/Makefile index 089cf5ae24..50573121ed 100644 --- a/tools/9pfsd/Makefile +++ b/tools/9pfsd/Makefile @@ -10,7 +10,7 @@ LDFLAGS += $(PTHREAD_LDFLAGS) TARGETS := xen-9pfsd -XEN-9PFSD_OBJS = xen-9pfsd.o +XEN-9PFSD_OBJS = xen-9pfsd.o io.o $(XEN-9PFSD_OBJS): CFLAGS += $(CFLAGS_libxenstore) $(XEN-9PFSD_OBJS): CFLAGS += $(CFLAGS_libxenevtchn) $(XEN-9PFSD_OBJS): CFLAGS += $(CFLAGS_libxengnttab) diff --git a/tools/9pfsd/io.c b/tools/9pfsd/io.c new file mode 100644 index 0000000000..eb7c136e09 --- /dev/null +++ b/tools/9pfsd/io.c @@ -0,0 +1,45 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ + +/* + * xen-9pfsd - Xen 9pfs daemon + * + * Copyright (C) 2024 Juergen Gross + * + * I/O thread handling. + */ + +#include +#include +#include + +#include "xen-9pfsd.h" + +static bool io_work_pending(struct ring *ring) +{ + if ( ring->stop_thread ) + return true; + return false; +} + +void *io_thread(void *arg) +{ + struct ring *ring = arg; + + while ( !ring->stop_thread ) + { + pthread_mutex_lock(&ring->mutex); + if ( !io_work_pending(ring) ) + { + if ( xenevtchn_unmask(xe, ring->evtchn) < 0 ) + syslog(LOG_WARNING, "xenevtchn_unmask() failed"); + pthread_cond_wait(&ring->cond, &ring->mutex); + } + pthread_mutex_unlock(&ring->mutex); + + /* TODO: I/O handling. */ + } + + ring->thread_active = false; + + return NULL; +} diff --git a/tools/9pfsd/xen-9pfsd.c b/tools/9pfsd/xen-9pfsd.c index 6939d01574..73b6c3a30e 100644 --- a/tools/9pfsd/xen-9pfsd.c +++ b/tools/9pfsd/xen-9pfsd.c @@ -24,34 +24,632 @@ #include #include +#include +#include +#include #include #include #include #include #include #include +#include #include #include #include -#include #include #include +#include "xen-9pfsd.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 volatile 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; + + /* Path must be absolute. */ + if ( device->host_path[0] != '/' ) + return 1; + + /* No double "/". */ + if ( strstr(device->host_path, "//") ) + return 1; + + /* No trailing "/" (includes refusing to share "/"). */ + if ( device->host_path[strlen(device->host_path) - 1] == '/' ) + 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 bool write_backend_node(device *device, const char *node, + const char *val) +{ + struct path p; + unsigned int num_perms; + struct xs_permissions *old_perms; + 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 false; + } + + old_perms = xs_get_permissions(xs, XBT_NULL, p.path, &num_perms); + if ( !old_perms ) + { + syslog(LOG_ERR, "error getting permissions for \"%s\"", p.path); + return false; + } + + perms[0] = old_perms[0]; + free(old_perms); + if ( !xs_set_permissions(xs, XBT_NULL, p.path, perms, 2) ) + { + syslog(LOG_ERR, "error setting permissions for \"%s\"", p.path); + return false; + } + + return true; +} + +static bool write_backend_node_uint(device *device, const char *node, + unsigned int val) +{ + char str[12]; + + snprintf(str, sizeof(str), "%u", val); + + return write_backend_node(device, node, str); +} + +static bool 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 false; + } + + device->backend_state = state; + + return true; +} + +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); + + if ( device->root_fd >= 0 ) + close(device->root_fd); + + free(device->host_path); + 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; + device->root_fd = -1; + + 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; + } + + 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; + } + device->root_fd = open(device->host_path, O_RDONLY | O_DIRECTORY); + if ( device->root_fd < 0 ) + goto err; + + if ( !write_backend_node(device, "versions", "1") ) + goto err; + if ( !write_backend_node_uint(device, "max-rings", MAX_RINGS) ) + goto err; + if ( !write_backend_node_uint(device, "max-ring-page-order", + MAX_RING_ORDER) ) + 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_ring(struct ring *ring) +{ + if ( !ring ) + return; + + if ( ring->thread_active ) + { + ring->stop_thread = true; + pthread_cond_signal(&ring->cond); + pthread_join(ring->thread, NULL); + ring->stop_thread = false; + } + + if ( ring->data.in ) + { + xengnttab_unmap(xg, ring->data.in, 1 << ring->ring_order); + ring->data.in = NULL; + } + if ( ring->intf ) + { + xengnttab_unmap(xg, ring->intf, 1 ); + ring->intf = NULL; + } + + if ( ring->evtchn ) + { + xenevtchn_unbind(xe, ring->evtchn); + ring->evtchn = 0; + } + + pthread_mutex_destroy(&ring->mutex); + pthread_cond_destroy(&ring->cond); +} + +static void disconnect_guest(device *device) +{ + unsigned int ring_idx; + + for ( ring_idx = 0; ring_idx < device->num_rings; ring_idx++ ) + { + disconnect_ring(device->ring[ring_idx]); + free(device->ring[ring_idx]); + device->ring[ring_idx] = NULL; + } + + device->num_rings = 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; + unsigned int ring_idx; + char node[20]; + struct ring *ring; + 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"); + device->num_rings = read_frontend_node_uint(device, "num-rings", 0); + if ( device->num_rings < 1 || device->num_rings > MAX_RINGS ) + return connect_err(device, "frontend specifies illegal ring number"); + + for ( ring_idx = 0; ring_idx < device->num_rings; ring_idx++ ) + { + ring = calloc(1, sizeof(*ring)); + if ( !ring ) + return connect_err(device, "could not allocate ring memory"); + device->ring[ring_idx] = ring; + ring->device = device; + pthread_cond_init(&ring->cond, NULL); + pthread_mutex_init(&ring->mutex, NULL); + + snprintf(node, sizeof(node), "event-channel-%u", ring_idx); + val = read_frontend_node_uint(device, node, 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"); + ring->evtchn = evtchn; + + snprintf(node, sizeof(node), "ring-ref%u", ring_idx); + val = read_frontend_node_uint(device, node, 0); + if ( val == 0 ) + return connect_err(device, + "frontend specifies illegal grant for ring"); + ring->intf = xengnttab_map_grant_ref(xg, device->domid, val, + PROT_READ | PROT_WRITE); + if ( !ring->intf ) + return connect_err(device, "could not map interface page"); + ring->ring_order = ring->intf->ring_order; + if ( ring->ring_order > MAX_RING_ORDER || ring->ring_order < 1 ) + return connect_err(device, "frontend specifies illegal ring order"); + ring->ring_size = XEN_FLEX_RING_SIZE(ring->ring_order); + ring->data.in = xengnttab_map_domain_grant_refs(xg, + 1 << ring->ring_order, + device->domid, + ring->intf->ref, + PROT_READ | PROT_WRITE); + if ( !ring->data.in ) + return connect_err(device, "could not map ring pages"); + ring->data.out = ring->data.in + ring->ring_size; + + if ( pthread_create(&ring->thread, NULL, io_thread, ring) ) + return connect_err(device, "could not start I/O thread"); + ring->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, "libxl/xen-9pfs"); + xs_unwatch(xs, "backend/xen_9pfs", "main"); + + remove_all_devices(); + } if ( xe ) xenevtchn_close(xe); if ( xg ) @@ -68,6 +666,33 @@ static void do_err(const char *msg) exit(1); } +static void handle_event(void) +{ + xenevtchn_port_or_error_t evtchn; + device *device; + struct ring *ring; + unsigned int ring_idx; + + evtchn = xenevtchn_pending(xe); + if ( evtchn < 0 ) + do_err("xenevtchn_pending() failed"); + + XEN_TAILQ_FOREACH( device, &devs, list ) + { + for ( ring_idx = 0; ring_idx < device->num_rings; ring_idx++ ) + { + ring = device->ring[ring_idx]; + if ( ring && ring->evtchn == evtchn ) + { + pthread_mutex_lock(&ring->mutex); + pthread_cond_signal(&ring->cond); + pthread_mutex_unlock(&ring->mutex); + return; + } + } + } +} + static void xen_connect(void) { xs_transaction_t t; @@ -124,6 +749,11 @@ 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 }, + { .events = POLLIN } + }; umask(027); if ( getenv("XEN_9PFSD_VERBOSE") ) @@ -136,9 +766,26 @@ 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, -1); } close_all(); diff --git a/tools/9pfsd/xen-9pfsd.h b/tools/9pfsd/xen-9pfsd.h new file mode 100644 index 0000000000..ff3562164a --- /dev/null +++ b/tools/9pfsd/xen-9pfsd.h @@ -0,0 +1,61 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ + +#ifndef XEN_9PFSD_H +#define XEN_9PFSD_H + +#include +#include +#include +#include +#include +#include +#include + +#define MAX_RINGS 4 +#define MAX_RING_ORDER 9 +#define MAX_OPEN_FILES_DEFAULT 5 + +typedef struct device device; + +struct ring { + device *device; + pthread_t thread; + bool thread_active; + bool stop_thread; + pthread_cond_t cond; + pthread_mutex_t mutex; + + evtchn_port_t evtchn; + struct xen_9pfs_data_intf *intf; + unsigned int ring_order; + RING_IDX ring_size; + struct xen_9pfs_data data; +}; + +struct device { + /* Admin data. */ + XEN_TAILQ_ENTRY(device) list; + unsigned int last_seen; /* Set in scan_backend(). */ + unsigned int domid; + unsigned int devid; + + /* 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; + unsigned int num_rings; + struct ring *ring[MAX_RINGS]; + int root_fd; +}; + +extern xenevtchn_handle *xe; + +void *io_thread(void *arg); + +#endif /* XEN_9PFSD_H */