| Message ID | 20240205105001.24171-15-jgross@suse.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | tools: enable xenstore-stubdom to use 9pfs | expand |
On Mon, Feb 5, 2024 at 5:51 AM Juergen Gross <jgross@suse.com> wrote: > > Add the read request of the 9pfs protocol. > > Signed-off-by: Juergen Gross <jgross@suse.com> > Reviewed-by: Jason Andryuk <jandryuk@gmail.com> > Acked-by: Anthony PERARD <anthony.perard@citrix.com> > --- > V2: > - make error check more readable (Jason Andryuk) > V4: > - add directory read support > --- > tools/xen-9pfsd/io.c | 90 ++++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 90 insertions(+) > > diff --git a/tools/xen-9pfsd/io.c b/tools/xen-9pfsd/io.c > index b763e3d8d9..cfbf3bef59 100644 > --- a/tools/xen-9pfsd/io.c > +++ b/tools/xen-9pfsd/io.c > + > + len = count; > + buf = ring->buffer + sizeof(*hdr) + sizeof(uint32_t); > + > + if ( fidp->isdir ) > + { > + struct dirent *dirent; > + struct stat st; > + struct p9_stat p9s; > + """ For directories, read returns an integral number of direc- tory entries exactly as in stat (see stat(5)), one for each member of the directory. The read request message must have offset equal to zero or the value of offset in the previous read on the directory, plus the number of bytes returned in the previous read. In other words, seeking other than to the beginning is illegal in a directory (see seek(2)). """ I think you need to check `off`. Looks like QEMU only checks for off == 0 and rewinds in that case. QEMU ignores other values. Regards, Jason > + while ( len != 0 ) > + { > + errno = 0; > + dirent = readdir(fidp->data); > + if ( !dirent ) > + { > + if ( errno ) > + goto err; > + break; > + } > + if ( fstatat(fidp->fd, dirent->d_name, &st, 0) < 0 ) > + goto err; > + fill_p9_stat(device, &p9s, &st, dirent->d_name); > + if ( p9s.size + sizeof(p9s.size) > len ) > + { > + seekdir(fidp->data, dirent->d_off); > + break; > + } > + fill_buffer_at(&buf, "s", &p9s); > + len -= p9s.size + sizeof(p9s.size); > + } > + } > + else > + { > + while ( len != 0 ) > + { > + ret = pread(fidp->fd, buf, len, off); > + if ( ret <= 0 ) > + break; > + len -= ret; > + buf += ret; > + off += ret; > + } > + if ( ret < 0 && len == count ) > + goto err; > + } > + > + buf = ring->buffer + sizeof(*hdr) + sizeof(uint32_t); > + len = count - len; > + fill_buffer(ring, hdr->cmd + 1, hdr->tag, "D", &len, buf); > + > + out: > + free_fid(device, fidp); > + > + return; > + > + err: > + p9_error(ring, hdr->tag, errno); > + goto out; > +} > +
On 08.02.24 02:28, Jason Andryuk wrote: > On Mon, Feb 5, 2024 at 5:51 AM Juergen Gross <jgross@suse.com> wrote: >> >> Add the read request of the 9pfs protocol. >> >> Signed-off-by: Juergen Gross <jgross@suse.com> >> Reviewed-by: Jason Andryuk <jandryuk@gmail.com> >> Acked-by: Anthony PERARD <anthony.perard@citrix.com> >> --- >> V2: >> - make error check more readable (Jason Andryuk) >> V4: >> - add directory read support >> --- >> tools/xen-9pfsd/io.c | 90 ++++++++++++++++++++++++++++++++++++++++++++ >> 1 file changed, 90 insertions(+) >> >> diff --git a/tools/xen-9pfsd/io.c b/tools/xen-9pfsd/io.c >> index b763e3d8d9..cfbf3bef59 100644 >> --- a/tools/xen-9pfsd/io.c >> +++ b/tools/xen-9pfsd/io.c > >> + >> + len = count; >> + buf = ring->buffer + sizeof(*hdr) + sizeof(uint32_t); >> + >> + if ( fidp->isdir ) >> + { >> + struct dirent *dirent; >> + struct stat st; >> + struct p9_stat p9s; >> + > > """ > For directories, read returns an integral number of direc- tory > entries exactly as in stat (see stat(5)), one for each member of the > directory. The read request message must have offset equal to zero or > the value of offset in the previous read on the directory, plus the > number of bytes returned in the previous read. In other words, seeking > other than to the beginning is illegal in a directory (see seek(2)). > """ > > I think you need to check `off`. Looks like QEMU only checks for off > == 0 and rewinds in that case. QEMU ignores other values. Oh, indeed. Thanks for noticing. I'll use the same approach as qemu. Juergen
diff --git a/tools/xen-9pfsd/io.c b/tools/xen-9pfsd/io.c index b763e3d8d9..cfbf3bef59 100644 --- a/tools/xen-9pfsd/io.c +++ b/tools/xen-9pfsd/io.c @@ -33,6 +33,7 @@ #define P9_CMD_WALK 110 #define P9_CMD_OPEN 112 #define P9_CMD_CREATE 114 +#define P9_CMD_READ 116 #define P9_CMD_WRITE 118 #define P9_CMD_CLUNK 120 #define P9_CMD_STAT 124 @@ -1247,6 +1248,91 @@ static void p9_stat(struct ring *ring, struct p9_header *hdr) free_fid(device, fidp); } +static void p9_read(struct ring *ring, struct p9_header *hdr) +{ + device *device = ring->device; + uint32_t fid; + uint64_t off; + unsigned int len; + uint32_t count; + void *buf; + struct p9_fid *fidp; + int ret; + + ret = fill_data(ring, "ULU", &fid, &off, &count); + if ( ret != 3 ) + { + p9_error(ring, hdr->tag, EINVAL); + return; + } + + fidp = get_fid_ref(device, fid); + if ( !fidp || !fidp->opened ) + { + errno = EBADF; + goto err; + } + + len = count; + buf = ring->buffer + sizeof(*hdr) + sizeof(uint32_t); + + if ( fidp->isdir ) + { + struct dirent *dirent; + struct stat st; + struct p9_stat p9s; + + while ( len != 0 ) + { + errno = 0; + dirent = readdir(fidp->data); + if ( !dirent ) + { + if ( errno ) + goto err; + break; + } + if ( fstatat(fidp->fd, dirent->d_name, &st, 0) < 0 ) + goto err; + fill_p9_stat(device, &p9s, &st, dirent->d_name); + if ( p9s.size + sizeof(p9s.size) > len ) + { + seekdir(fidp->data, dirent->d_off); + break; + } + fill_buffer_at(&buf, "s", &p9s); + len -= p9s.size + sizeof(p9s.size); + } + } + else + { + while ( len != 0 ) + { + ret = pread(fidp->fd, buf, len, off); + if ( ret <= 0 ) + break; + len -= ret; + buf += ret; + off += ret; + } + if ( ret < 0 && len == count ) + goto err; + } + + buf = ring->buffer + sizeof(*hdr) + sizeof(uint32_t); + len = count - len; + fill_buffer(ring, hdr->cmd + 1, hdr->tag, "D", &len, buf); + + out: + free_fid(device, fidp); + + return; + + err: + p9_error(ring, hdr->tag, errno); + goto out; +} + static void p9_write(struct ring *ring, struct p9_header *hdr) { device *device = ring->device; @@ -1371,6 +1457,10 @@ void *io_thread(void *arg) p9_create(ring, &hdr); break; + case P9_CMD_READ: + p9_read(ring, &hdr); + break; + case P9_CMD_WRITE: p9_write(ring, &hdr); break;