| Message ID | 2e88acab7b3f998ceff7232b5e3d6a8a6d2a6f8b.1650370026.git.qemu_oss@crudebyte.com |
|---|---|
| State | New |
| Headers | show |
| Series | 9pfs: macOS host fixes | expand |
On Tue, Apr 19, 2022 at 8:18 AM Christian Schoenebeck < qemu_oss@crudebyte.com> wrote: > mknod() on macOS does not support creating sockets, so divert to > call sequence socket(), bind() and chmod() respectively if S_IFSOCK > was passed with mode argument. > > Link: https://lore.kernel.org/qemu-devel/17933734.zYzKuhC07K@silver/ > Signed-off-by > <https://lore.kernel.org/qemu-devel/17933734.zYzKuhC07K@silver/Signed-off-by>: > Christian Schoenebeck <qemu_oss@crudebyte.com> > --- > hw/9pfs/9p-util-darwin.c | 24 +++++++++++++++++++++++- > 1 file changed, 23 insertions(+), 1 deletion(-) > > diff --git a/hw/9pfs/9p-util-darwin.c b/hw/9pfs/9p-util-darwin.c > index 53e0625501..252a6fc5dd 100644 > --- a/hw/9pfs/9p-util-darwin.c > +++ b/hw/9pfs/9p-util-darwin.c > @@ -74,6 +74,24 @@ int fsetxattrat_nofollow(int dirfd, const char > *filename, const char *name, > */ > #if defined CONFIG_PTHREAD_FCHDIR_NP > > +static int create_socket_file_at_cwd(const char *filename, mode_t mode) { > + int fd, err; > + struct sockaddr_un addr = { > + .sun_family = AF_UNIX > + }; > + > + fd = socket(PF_UNIX, SOCK_DGRAM, 0); > + if (fd < 0) { > + return fd; > + } > + snprintf(addr.sun_path, sizeof(addr.sun_path), "./%s", filename); > + err = bind(fd, (struct sockaddr *) &addr, sizeof(addr)); > + if (err < 0) { > + return err; > + } > + return chmod(addr.sun_path, mode); > +} > + > int qemu_mknodat(int dirfd, const char *filename, mode_t mode, dev_t dev) > { > int preserved_errno, err; > @@ -88,7 +106,11 @@ int qemu_mknodat(int dirfd, const char *filename, > mode_t mode, dev_t dev) > if (pthread_fchdir_np(dirfd) < 0) { > return -1; > } > - err = mknod(filename, mode, dev); > + if (S_ISSOCK(mode)) { > + err = create_socket_file_at_cwd(filename, mode); > + } else { > + err = mknod(filename, mode, dev); > + } > preserved_errno = errno; > /* Stop using the thread-local cwd */ > pthread_fchdir_np(-1); > -- > 2.32.0 (Apple Git-132) > Reviewed-by: Will Cohen <wwcohen@gmail.com>
On Tue, 19 Apr 2022 13:41:03 +0200 Christian Schoenebeck <qemu_oss@crudebyte.com> wrote: > mknod() on macOS does not support creating sockets, so divert to > call sequence socket(), bind() and chmod() respectively if S_IFSOCK > was passed with mode argument. > Hmm... thinking again about this one : QEMU on linux calls the libc version of mknodat() which doesn't seem to support S_IFSOCK according to the mknod(3P) manual page. So I'm not sure there's something to be actually fixed here... what's the observed behavior on linux ? > Link: https://lore.kernel.org/qemu-devel/17933734.zYzKuhC07K@silver/ > Signed-off-by: Christian Schoenebeck <qemu_oss@crudebyte.com> > --- > hw/9pfs/9p-util-darwin.c | 24 +++++++++++++++++++++++- > 1 file changed, 23 insertions(+), 1 deletion(-) > > diff --git a/hw/9pfs/9p-util-darwin.c b/hw/9pfs/9p-util-darwin.c > index 53e0625501..252a6fc5dd 100644 > --- a/hw/9pfs/9p-util-darwin.c > +++ b/hw/9pfs/9p-util-darwin.c > @@ -74,6 +74,24 @@ int fsetxattrat_nofollow(int dirfd, const char *filename, const char *name, > */ > #if defined CONFIG_PTHREAD_FCHDIR_NP > > +static int create_socket_file_at_cwd(const char *filename, mode_t mode) { > + int fd, err; > + struct sockaddr_un addr = { > + .sun_family = AF_UNIX > + }; > + > + fd = socket(PF_UNIX, SOCK_DGRAM, 0); > + if (fd < 0) { > + return fd; > + } > + snprintf(addr.sun_path, sizeof(addr.sun_path), "./%s", filename); > + err = bind(fd, (struct sockaddr *) &addr, sizeof(addr)); > + if (err < 0) { > + return err; > + } > + return chmod(addr.sun_path, mode); > +} > + > int qemu_mknodat(int dirfd, const char *filename, mode_t mode, dev_t dev) > { > int preserved_errno, err; > @@ -88,7 +106,11 @@ int qemu_mknodat(int dirfd, const char *filename, mode_t mode, dev_t dev) > if (pthread_fchdir_np(dirfd) < 0) { > return -1; > } > - err = mknod(filename, mode, dev); > + if (S_ISSOCK(mode)) { > + err = create_socket_file_at_cwd(filename, mode); > + } else { > + err = mknod(filename, mode, dev); > + } > preserved_errno = errno; > /* Stop using the thread-local cwd */ > pthread_fchdir_np(-1);
On Mittwoch, 20. April 2022 11:09:46 CEST Greg Kurz wrote: > On Tue, 19 Apr 2022 13:41:03 +0200 > > Christian Schoenebeck <qemu_oss@crudebyte.com> wrote: > > mknod() on macOS does not support creating sockets, so divert to > > call sequence socket(), bind() and chmod() respectively if S_IFSOCK > > was passed with mode argument. > > Hmm... thinking again about this one : QEMU on linux calls the libc > version of mknodat() which doesn't seem to support S_IFSOCK according > to the mknod(3P) manual page. So I'm not sure there's something to > be actually fixed here... what's the observed behavior on linux ? It's unclear to me where you got that from. In all Linux man pages I looked up so far it said S_IFSOCK was supported. But I also tested this now with security_model=none on a Linux host and it works as expected, i.e. it creates a file of type socket on the Linux host filesystem. We are really talking about a Linux host, right? Best regards, Christian Schoenebeck
On Wed, 20 Apr 2022 12:28:01 +0200 Christian Schoenebeck <qemu_oss@crudebyte.com> wrote: > On Mittwoch, 20. April 2022 11:09:46 CEST Greg Kurz wrote: > > On Tue, 19 Apr 2022 13:41:03 +0200 > > > > Christian Schoenebeck <qemu_oss@crudebyte.com> wrote: > > > mknod() on macOS does not support creating sockets, so divert to > > > call sequence socket(), bind() and chmod() respectively if S_IFSOCK > > > was passed with mode argument. > > > > Hmm... thinking again about this one : QEMU on linux calls the libc > > version of mknodat() which doesn't seem to support S_IFSOCK according > > to the mknod(3P) manual page. So I'm not sure there's something to > > be actually fixed here... what's the observed behavior on linux ? > > It's unclear to me where you got that from. In all Linux man pages I looked up > so far it said S_IFSOCK was supported. But I also tested this now with > security_model=none on a Linux host and it works as expected, i.e. it creates > a file of type socket on the Linux host filesystem. > > We are really talking about a Linux host, right? > Yes but you can forget this remark. I've checked the glibc sources and it directly calls the syscall... I guess I got confused by the mknod(3P) manual page. Sorry for the noise :-) > Best regards, > Christian Schoenebeck > >
On Tue, 19 Apr 2022 13:41:03 +0200 Christian Schoenebeck <qemu_oss@crudebyte.com> wrote: > mknod() on macOS does not support creating sockets, so divert to > call sequence socket(), bind() and chmod() respectively if S_IFSOCK > was passed with mode argument. > > Link: https://lore.kernel.org/qemu-devel/17933734.zYzKuhC07K@silver/ > Signed-off-by: Christian Schoenebeck <qemu_oss@crudebyte.com> > --- > hw/9pfs/9p-util-darwin.c | 24 +++++++++++++++++++++++- > 1 file changed, 23 insertions(+), 1 deletion(-) > > diff --git a/hw/9pfs/9p-util-darwin.c b/hw/9pfs/9p-util-darwin.c > index 53e0625501..252a6fc5dd 100644 > --- a/hw/9pfs/9p-util-darwin.c > +++ b/hw/9pfs/9p-util-darwin.c > @@ -74,6 +74,24 @@ int fsetxattrat_nofollow(int dirfd, const char *filename, const char *name, > */ > #if defined CONFIG_PTHREAD_FCHDIR_NP > > +static int create_socket_file_at_cwd(const char *filename, mode_t mode) { > + int fd, err; > + struct sockaddr_un addr = { > + .sun_family = AF_UNIX > + }; > + > + fd = socket(PF_UNIX, SOCK_DGRAM, 0); > + if (fd < 0) { > + return fd; > + } > + snprintf(addr.sun_path, sizeof(addr.sun_path), "./%s", filename); > + err = bind(fd, (struct sockaddr *) &addr, sizeof(addr)); > + if (err < 0) { > + return err; > + } > + return chmod(addr.sun_path, mode); As with the other patch, you should close() the socket. > +} > + > int qemu_mknodat(int dirfd, const char *filename, mode_t mode, dev_t dev) > { > int preserved_errno, err; > @@ -88,7 +106,11 @@ int qemu_mknodat(int dirfd, const char *filename, mode_t mode, dev_t dev) > if (pthread_fchdir_np(dirfd) < 0) { > return -1; > } > - err = mknod(filename, mode, dev); > + if (S_ISSOCK(mode)) { > + err = create_socket_file_at_cwd(filename, mode); > + } else { > + err = mknod(filename, mode, dev); > + } > preserved_errno = errno; > /* Stop using the thread-local cwd */ > pthread_fchdir_np(-1);
On Mittwoch, 20. April 2022 14:10:44 CEST Greg Kurz wrote: > On Tue, 19 Apr 2022 13:41:03 +0200 > > Christian Schoenebeck <qemu_oss@crudebyte.com> wrote: > > mknod() on macOS does not support creating sockets, so divert to > > call sequence socket(), bind() and chmod() respectively if S_IFSOCK > > was passed with mode argument. > > > > Link: https://lore.kernel.org/qemu-devel/17933734.zYzKuhC07K@silver/ > > Signed-off-by: Christian Schoenebeck <qemu_oss@crudebyte.com> > > --- > > > > hw/9pfs/9p-util-darwin.c | 24 +++++++++++++++++++++++- > > 1 file changed, 23 insertions(+), 1 deletion(-) > > > > diff --git a/hw/9pfs/9p-util-darwin.c b/hw/9pfs/9p-util-darwin.c > > index 53e0625501..252a6fc5dd 100644 > > --- a/hw/9pfs/9p-util-darwin.c > > +++ b/hw/9pfs/9p-util-darwin.c > > @@ -74,6 +74,24 @@ int fsetxattrat_nofollow(int dirfd, const char > > *filename, const char *name,> > > */ > > > > #if defined CONFIG_PTHREAD_FCHDIR_NP > > > > +static int create_socket_file_at_cwd(const char *filename, mode_t mode) { > > + int fd, err; > > + struct sockaddr_un addr = { > > + .sun_family = AF_UNIX > > + }; > > + > > + fd = socket(PF_UNIX, SOCK_DGRAM, 0); > > + if (fd < 0) { > > + return fd; > > + } > > + snprintf(addr.sun_path, sizeof(addr.sun_path), "./%s", filename); > > + err = bind(fd, (struct sockaddr *) &addr, sizeof(addr)); > > + if (err < 0) { > > + return err; > > + } > > + return chmod(addr.sun_path, mode); > > As with the other patch, you should close() the socket. I was concerned that close(fd) might cause the socket file to disappear. But I just tested this now on macOS and it works fine. So will be fixed in v2. Thanks! Best regards, Christian Schoenebeck
diff --git a/hw/9pfs/9p-util-darwin.c b/hw/9pfs/9p-util-darwin.c index 53e0625501..252a6fc5dd 100644 --- a/hw/9pfs/9p-util-darwin.c +++ b/hw/9pfs/9p-util-darwin.c @@ -74,6 +74,24 @@ int fsetxattrat_nofollow(int dirfd, const char *filename, const char *name, */ #if defined CONFIG_PTHREAD_FCHDIR_NP +static int create_socket_file_at_cwd(const char *filename, mode_t mode) { + int fd, err; + struct sockaddr_un addr = { + .sun_family = AF_UNIX + }; + + fd = socket(PF_UNIX, SOCK_DGRAM, 0); + if (fd < 0) { + return fd; + } + snprintf(addr.sun_path, sizeof(addr.sun_path), "./%s", filename); + err = bind(fd, (struct sockaddr *) &addr, sizeof(addr)); + if (err < 0) { + return err; + } + return chmod(addr.sun_path, mode); +} + int qemu_mknodat(int dirfd, const char *filename, mode_t mode, dev_t dev) { int preserved_errno, err; @@ -88,7 +106,11 @@ int qemu_mknodat(int dirfd, const char *filename, mode_t mode, dev_t dev) if (pthread_fchdir_np(dirfd) < 0) { return -1; } - err = mknod(filename, mode, dev); + if (S_ISSOCK(mode)) { + err = create_socket_file_at_cwd(filename, mode); + } else { + err = mknod(filename, mode, dev); + } preserved_errno = errno; /* Stop using the thread-local cwd */ pthread_fchdir_np(-1);
mknod() on macOS does not support creating sockets, so divert to call sequence socket(), bind() and chmod() respectively if S_IFSOCK was passed with mode argument. Link: https://lore.kernel.org/qemu-devel/17933734.zYzKuhC07K@silver/ Signed-off-by: Christian Schoenebeck <qemu_oss@crudebyte.com> --- hw/9pfs/9p-util-darwin.c | 24 +++++++++++++++++++++++- 1 file changed, 23 insertions(+), 1 deletion(-)