| Message ID | 20231101093325.30302-10-jgross@suse.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | tools: enable xenstore-stubdom to use 9pfs | expand |
On Wed, Nov 1, 2023 at 6:13 AM Juergen Gross <jgross@suse.com> wrote: > > Add the open request of the 9pfs protocol. > > Signed-off-by: Juergen Gross <jgross@suse.com> > --- > tools/xenlogd/io.c | 130 ++++++++++++++++++++++++++++++++++++++++ > tools/xenlogd/xenlogd.h | 4 ++ > 2 files changed, 134 insertions(+) > > diff --git a/tools/xenlogd/io.c b/tools/xenlogd/io.c > index 778e1dc2c9..c2b259f42e 100644 > --- a/tools/xenlogd/io.c > +++ b/tools/xenlogd/io.c > @@ -734,6 +745,121 @@ static void p9_walk(device *device, struct p9_header *hdr) > free(names); > } > > +static int open_flags_from_mode(uint8_t mode) > +{ > + int flags; > + > + switch ( mode & P9_OMODEMASK ) > + { > + case P9_OREAD: > + flags = O_RDONLY; > + break; > + > + case P9_OWRITE: > + flags = O_WRONLY; > + break; > + > + case P9_ORDWR: > + flags = O_RDWR; > + break; > + > + default: > + return -1; > + } > + > + if ( mode & P9_OTRUNC ) > + flags |= O_TRUNC; """ In addition, if mode has the OTRUNC (0x10) bit set, the file is to be truncated, which requires write permission (if the file is append-only, and permission is granted, the open succeeds but the file will not be trun- cated); """ This relies on libc O_TRUNC handling - I think that is probably better than something custom so you get the libc semantics. > + > + return flags; > +} > + > +static unsigned int get_iounit(device *device, struct stat *st) > +{ > + return (device->max_size - st->st_blksize) & ~(st->st_blksize - 1); > +} > + > +static void p9_open(device *device, struct p9_header *hdr) > +{ > + uint32_t fid; > + uint8_t mode; > + struct p9_fid *fidp; > + struct stat st; > + struct p9_qid qid; > + uint32_t iounit; > + int flags; > + int ret; > + > + ret = fill_data(device, "Ub", &fid, &mode); > + if ( ret != 2 ) > + { > + p9_error(device, hdr->tag, EINVAL); > + return; > + } > + if ( mode & ~(P9_OMODEMASK | P9_OTRUNC | P9_OREMOVE) ) > + { > + p9_error(device, hdr->tag, EINVAL); > + return; > + } > + > + fidp = find_fid(device, fid); > + if ( !fidp ) > + { > + p9_error(device, hdr->tag, ENOENT); If the host_path points at a populated directory, there is nothing that populates the fids for pre-existing files and directories? So those files cannot be opened? I guess that's not needed for Xenstore-stubdom? Thanks, Jason
On 06.11.23 20:33, Jason Andryuk wrote: > On Wed, Nov 1, 2023 at 6:13 AM Juergen Gross <jgross@suse.com> wrote: >> >> Add the open request of the 9pfs protocol. >> >> Signed-off-by: Juergen Gross <jgross@suse.com> >> --- >> tools/xenlogd/io.c | 130 ++++++++++++++++++++++++++++++++++++++++ >> tools/xenlogd/xenlogd.h | 4 ++ >> 2 files changed, 134 insertions(+) >> >> diff --git a/tools/xenlogd/io.c b/tools/xenlogd/io.c >> index 778e1dc2c9..c2b259f42e 100644 >> --- a/tools/xenlogd/io.c >> +++ b/tools/xenlogd/io.c > >> @@ -734,6 +745,121 @@ static void p9_walk(device *device, struct p9_header *hdr) >> free(names); >> } >> >> +static int open_flags_from_mode(uint8_t mode) >> +{ >> + int flags; >> + >> + switch ( mode & P9_OMODEMASK ) >> + { >> + case P9_OREAD: >> + flags = O_RDONLY; >> + break; >> + >> + case P9_OWRITE: >> + flags = O_WRONLY; >> + break; >> + >> + case P9_ORDWR: >> + flags = O_RDWR; >> + break; >> + >> + default: >> + return -1; >> + } >> + >> + if ( mode & P9_OTRUNC ) >> + flags |= O_TRUNC; > > """ > In addition, if mode has the OTRUNC (0x10) bit set, the file is to be > truncated, which requires write permission (if the file is > append-only, and permission is granted, the open succeeds but the file > will not be trun- cated); > """ > > This relies on libc O_TRUNC handling - I think that is probably better > than something custom so you get the libc semantics. That was my thinking, yes. > >> + >> + return flags; >> +} >> + >> +static unsigned int get_iounit(device *device, struct stat *st) >> +{ >> + return (device->max_size - st->st_blksize) & ~(st->st_blksize - 1); >> +} >> + >> +static void p9_open(device *device, struct p9_header *hdr) >> +{ >> + uint32_t fid; >> + uint8_t mode; >> + struct p9_fid *fidp; >> + struct stat st; >> + struct p9_qid qid; >> + uint32_t iounit; >> + int flags; >> + int ret; >> + >> + ret = fill_data(device, "Ub", &fid, &mode); >> + if ( ret != 2 ) >> + { >> + p9_error(device, hdr->tag, EINVAL); >> + return; >> + } >> + if ( mode & ~(P9_OMODEMASK | P9_OTRUNC | P9_OREMOVE) ) >> + { >> + p9_error(device, hdr->tag, EINVAL); >> + return; >> + } >> + >> + fidp = find_fid(device, fid); >> + if ( !fidp ) >> + { >> + p9_error(device, hdr->tag, ENOENT); > > If the host_path points at a populated directory, there is nothing > that populates the fids for pre-existing files and directories? So > those files cannot be opened? I guess that's not needed for > Xenstore-stubdom? It is the guest which is associating a fid with a file. For opening an existing file the guest should use the WALK command to walk the path from a known fid (e.g. the root fid associated at ATTACH time) to the target file. Juergen
diff --git a/tools/xenlogd/io.c b/tools/xenlogd/io.c index 778e1dc2c9..c2b259f42e 100644 --- a/tools/xenlogd/io.c +++ b/tools/xenlogd/io.c @@ -18,6 +18,8 @@ #include <syslog.h> #include <sys/types.h> #include <sys/stat.h> +#include <dirent.h> +#include <fcntl.h> #include <xenctrl.h> /* For cpu barriers. */ #include <xen-tools/common-macros.h> @@ -28,6 +30,15 @@ #define P9_CMD_ATTACH 104 #define P9_CMD_ERROR 107 #define P9_CMD_WALK 110 +#define P9_CMD_OPEN 112 + +/* P9 protocol open flags. */ +#define P9_OREAD 0 /* read */ +#define P9_OWRITE 1 /* write */ +#define P9_ORDWR 2 /* read and write */ +#define P9_OMODEMASK 0x03 +#define P9_OTRUNC 0x10 /* or'ed in, truncate file first */ +#define P9_OREMOVE 0x40 /* or'ed in, remove file after clunk */ #define P9_MIN_MSIZE 2048 #define P9_VERSION "9P2000.u" @@ -734,6 +745,121 @@ static void p9_walk(device *device, struct p9_header *hdr) free(names); } +static int open_flags_from_mode(uint8_t mode) +{ + int flags; + + switch ( mode & P9_OMODEMASK ) + { + case P9_OREAD: + flags = O_RDONLY; + break; + + case P9_OWRITE: + flags = O_WRONLY; + break; + + case P9_ORDWR: + flags = O_RDWR; + break; + + default: + return -1; + } + + if ( mode & P9_OTRUNC ) + flags |= O_TRUNC; + + return flags; +} + +static unsigned int get_iounit(device *device, struct stat *st) +{ + return (device->max_size - st->st_blksize) & ~(st->st_blksize - 1); +} + +static void p9_open(device *device, struct p9_header *hdr) +{ + uint32_t fid; + uint8_t mode; + struct p9_fid *fidp; + struct stat st; + struct p9_qid qid; + uint32_t iounit; + int flags; + int ret; + + ret = fill_data(device, "Ub", &fid, &mode); + if ( ret != 2 ) + { + p9_error(device, hdr->tag, EINVAL); + return; + } + if ( mode & ~(P9_OMODEMASK | P9_OTRUNC | P9_OREMOVE) ) + { + p9_error(device, hdr->tag, EINVAL); + return; + } + + fidp = find_fid(device, fid); + if ( !fidp ) + { + p9_error(device, hdr->tag, ENOENT); + return; + } + if ( fidp->opened ) + { + p9_error(device, hdr->tag, EINVAL); + return; + } + + if ( stat(fidp->path, &st) < 0 ) + { + p9_error(device, hdr->tag, ENOENT); + return; + } + + fidp->isdir = S_ISDIR(st.st_mode); + fidp->mode = mode; + if ( fidp->isdir ) + { + if ( mode != P9_OREAD ) + { + p9_error(device, hdr->tag, EINVAL); + return; + } + fidp->data = opendir(fidp->path); + if ( !fidp->data ) + { + p9_error(device, hdr->tag, errno); + return; + } + fidp->fd = dirfd(fidp->data); + } + else + { + flags = open_flags_from_mode(mode); + if ( flags < 0 ) + { + p9_error(device, hdr->tag, EINVAL); + return; + } + + fidp->fd = open(fidp->path, flags); + if ( fidp->fd < 0 ) + { + p9_error(device, hdr->tag, errno); + return; + } + } + + fill_qid(fidp->path, &qid, &st); + iounit = get_iounit(device, &st); + fidp->opened = true; + + fill_buffer(device, hdr->cmd + 1, hdr->tag, "QU", &qid, &iounit); +} + void *io_thread(void *arg) { device *device = arg; @@ -801,6 +927,10 @@ void *io_thread(void *arg) p9_walk(device, &hdr); break; + case P9_CMD_OPEN: + p9_open(device, &hdr); + break; + default: syslog(LOG_DEBUG, "%u.%u sent unhandled command %u\n", device->domid, device->devid, hdr.cmd); diff --git a/tools/xenlogd/xenlogd.h b/tools/xenlogd/xenlogd.h index 23f013af9e..6b7b5e2b91 100644 --- a/tools/xenlogd/xenlogd.h +++ b/tools/xenlogd/xenlogd.h @@ -22,7 +22,11 @@ struct p9_header { struct p9_fid { XEN_TAILQ_ENTRY(struct p9_fid) list; unsigned int fid; + int fd; + uint8_t mode; bool opened; + bool isdir; + void *data; /* File type specific. */ char path[]; };
Add the open request of the 9pfs protocol. Signed-off-by: Juergen Gross <jgross@suse.com> --- tools/xenlogd/io.c | 130 ++++++++++++++++++++++++++++++++++++++++ tools/xenlogd/xenlogd.h | 4 ++ 2 files changed, 134 insertions(+)