[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [xen staging] tools/xen-9pfsd: add 9pfs attach request support
commit 27815b5f8f82236541a42602ce356ca6d4d1348f Author: Juergen Gross <jgross@xxxxxxxx> AuthorDate: Thu Feb 15 14:04:54 2024 +0100 Commit: Andrew Cooper <andrew.cooper3@xxxxxxxxxx> CommitDate: Thu Feb 15 16:24:39 2024 +0000 tools/xen-9pfsd: add 9pfs attach request support Add the attach request of the 9pfs protocol. This introduces the "fid" scheme of the 9pfs protocol. As this will be needed later, use a dedicated memory allocation function in alloc_fid() and prepare a fid reference count. For filling the qid data take the approach from the qemu 9pfs backend implementation. Signed-off-by: Juergen Gross <jgross@xxxxxxxx> Acked-by: Anthony PERARD <anthony.perard@xxxxxxxxxx> Reviewed-by: Jason Andryuk <jandryuk@xxxxxxxxx> --- tools/9pfsd/io.c | 162 ++++++++++++++++++++++++++++++++++++++++++++++++ tools/9pfsd/xen-9pfsd.c | 6 ++ tools/9pfsd/xen-9pfsd.h | 14 +++++ 3 files changed, 182 insertions(+) diff --git a/tools/9pfsd/io.c b/tools/9pfsd/io.c index 27571da192..3fd4289f7c 100644 --- a/tools/9pfsd/io.c +++ b/tools/9pfsd/io.c @@ -11,11 +11,14 @@ * before looking for the next request. */ +#include <assert.h> #include <errno.h> #include <stdbool.h> #include <stdlib.h> #include <string.h> #include <syslog.h> +#include <sys/types.h> +#include <sys/stat.h> #include <xenctrl.h> /* For cpu barriers. */ #include <xen-tools/common-macros.h> @@ -23,6 +26,7 @@ /* P9 protocol commands (response is either cmd+1 or P9_CMD_ERROR). */ #define P9_CMD_VERSION 100 +#define P9_CMD_ATTACH 104 #define P9_CMD_ERROR 107 #define P9_MIN_MSIZE 2048 @@ -461,6 +465,124 @@ static int fill_data(struct ring *ring, const char *fmt, ...) return pars; } +static struct p9_fid *find_fid(device *device, unsigned int fid) +{ + struct p9_fid *fidp; + + XEN_TAILQ_FOREACH(fidp, &device->fids, list) + { + if ( fidp->fid == fid ) + return fidp; + } + + return NULL; +} + +static struct p9_fid *alloc_fid_mem(device *device, unsigned int fid, + const char *path) +{ + struct p9_fid *fidp; + + fidp = calloc(sizeof(*fidp) + strlen(path) + 1, 1); + if ( !fidp ) + return NULL; + + fidp->fid = fid; + strcpy(fidp->path, path); + + return fidp; +} + +static struct p9_fid *alloc_fid(device *device, unsigned int fid, + const char *path) +{ + struct p9_fid *fidp = NULL; + + pthread_mutex_lock(&device->fid_mutex); + + if ( find_fid(device, fid) ) + { + errno = EBADF; + goto out; + } + + if ( device->n_fids >= device->max_open_files ) + { + errno = EMFILE; + goto out; + } + + fidp = alloc_fid_mem(device, fid, path); + if ( !fidp ) + goto out; + + fidp->ref = 1; + XEN_TAILQ_INSERT_HEAD(&device->fids, fidp, list); + device->n_fids++; + + out: + pthread_mutex_unlock(&device->fid_mutex); + + return fidp; +} + +static void free_fid(device *device, struct p9_fid *fidp) +{ + if ( !fidp ) + return; + + pthread_mutex_lock(&device->fid_mutex); + + fidp->ref--; + if ( !fidp->ref ) + { + device->n_fids--; + XEN_TAILQ_REMOVE(&device->fids, fidp, list); + free(fidp); + } + + pthread_mutex_unlock(&device->fid_mutex); +} + +void free_fids(device *device) +{ + struct p9_fid *fidp; + + while ( (fidp = XEN_TAILQ_FIRST(&device->fids)) != NULL ) + { + XEN_TAILQ_REMOVE(&device->fids, fidp, list); + free(fidp); + } +} + +static const char *relpath_from_path(const char *path) +{ + if (!strcmp(path, "/")) + return "."; + + return (path[0] == '/') ? path + 1 : path; +} + +static int fill_qid(device *device, const char *path, struct p9_qid *qid, + const struct stat *stbuf) +{ + struct stat st; + + if ( !stbuf ) + { + if ( fstatat(device->root_fd, path, &st, 0) ) + return errno; + + stbuf = &st; + } + + qid->type = S_ISDIR(stbuf->st_mode) ? QID_TYPE_DIR : 0; + qid->version = stbuf->st_mtime ^ (stbuf->st_size << 8); + qid->path = stbuf->st_ino; + + return 0; +} + static void p9_error(struct ring *ring, uint16_t tag, uint32_t err) { unsigned int erroff; @@ -502,6 +624,42 @@ static void p9_version(struct ring *ring, struct p9_header *hdr) fill_buffer(ring, hdr->cmd + 1, hdr->tag, "US", &ring->max_size, version); } +static void p9_attach(struct ring *ring, struct p9_header *hdr) +{ + device *device = ring->device; + uint32_t fid; + uint32_t dummy_u32; + unsigned int dummy_uint; + struct p9_qid qid; + int ret; + + ret = fill_data(ring, "UUSSU", &fid, &dummy_u32, &dummy_uint, &dummy_uint, + &dummy_u32); + if ( ret != 5 ) + { + p9_error(ring, hdr->tag, errno); + return; + } + + device->root_fid = alloc_fid(device, fid, relpath_from_path("/")); + if ( !device->root_fid ) + { + p9_error(ring, hdr->tag, errno); + return; + } + + ret = fill_qid(device, device->root_fid->path, &qid, NULL); + if ( ret ) + { + free_fid(device, device->root_fid); + device->root_fid = NULL; + p9_error(ring, hdr->tag, ret); + return; + } + + fill_buffer(ring, hdr->cmd + 1, hdr->tag, "Q", &qid); +} + void *io_thread(void *arg) { struct ring *ring = arg; @@ -561,6 +719,10 @@ void *io_thread(void *arg) p9_version(ring, &hdr); break; + case P9_CMD_ATTACH: + p9_attach(ring, &hdr); + break; + default: syslog(LOG_DEBUG, "%u.%u sent unhandled command %u\n", ring->device->domid, ring->device->devid, hdr.cmd); diff --git a/tools/9pfsd/xen-9pfsd.c b/tools/9pfsd/xen-9pfsd.c index 73b6c3a30e..b83b896bcc 100644 --- a/tools/9pfsd/xen-9pfsd.c +++ b/tools/9pfsd/xen-9pfsd.c @@ -304,6 +304,9 @@ static device *new_device(unsigned int domid, unsigned int devid) return NULL; } + pthread_mutex_init(&device->fid_mutex, NULL); + XEN_TAILQ_INIT(&device->fids); + val = read_backend_node(device, "security_model"); if ( !val || strcmp(val, "none") ) { @@ -399,6 +402,8 @@ static void disconnect_guest(device *device) } device->num_rings = 0; + + free_fids(device); } static void close_device(device *device, enum xenbus_state state) @@ -482,6 +487,7 @@ static void remove_device(device *device) XEN_TAILQ_REMOVE(&devs, device, list); disconnect_guest(device); + pthread_mutex_destroy(&device->fid_mutex); free_device(device); } diff --git a/tools/9pfsd/xen-9pfsd.h b/tools/9pfsd/xen-9pfsd.h index 0cde0d2bb8..6c755411a7 100644 --- a/tools/9pfsd/xen-9pfsd.h +++ b/tools/9pfsd/xen-9pfsd.h @@ -21,6 +21,13 @@ struct p9_header { uint16_t tag; } __attribute__((packed)); +struct p9_fid { + XEN_TAILQ_ENTRY(struct p9_fid) list; + unsigned int fid; + unsigned int ref; + char path[]; +}; + typedef struct device device; struct ring { @@ -71,10 +78,17 @@ struct device { unsigned int num_rings; struct ring *ring[MAX_RINGS]; int root_fd; + + /* File system handling. */ + pthread_mutex_t fid_mutex; + XEN_TAILQ_HEAD(fidhead, struct p9_fid) fids; + struct p9_fid *root_fid; + unsigned int n_fids; }; extern xenevtchn_handle *xe; void *io_thread(void *arg); +void free_fids(device *device); #endif /* XEN_9PFSD_H */ -- generated by git-patchbot for /home/xen/git/xen.git#staging
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