| Message ID | 20241112-statmount-v1-1-d98090c4c8be@kernel.org (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | samples: add a mountinfo program to demonstrate statmount()/listmount() | expand |
On Tue, Nov 12, 2024 at 04:21:23PM -0500, Jeff Layton wrote: > Add a new "mountinfo" sample userland program that demonstrates how to > use statmount() and listmount() to get at the same info that > /proc/pid/mountinfo provides. > > The output of the program tries to mimic the mountinfo procfile > contents. With the -p flag, it can be pointed at an arbitrary pid to > print out info about its mount namespace. With the -r flag it will > attempt to walk all of the namespaces under the pid's mount namespace > and dump out mount info from all of them. > > Signed-off-by: Jeff Layton <jlayton@kernel.org> > --- > We had some recent queries internally asking how to use the new > statmount() and listmount() interfaces. I was doing some other work in > this area, so I whipped up this tool. My hope is that this will > represent something of a "rosetta stone" for how to translate between > mountinfo and statmount(), and an example for other people looking to > use the new interfaces. > > It may also be possible to use this as the basis for a statmount() > testcase. We can call this program, and compare its output to the > mountinfo file. > --- Yes, that's great. Thanks for doing that! > samples/vfs/.gitignore | 1 + > samples/vfs/Makefile | 2 +- > samples/vfs/mountinfo.c | 271 ++++++++++++++++++++++++++++++++++++++++++++++++ > 3 files changed, 273 insertions(+), 1 deletion(-) > > diff --git a/samples/vfs/.gitignore b/samples/vfs/.gitignore > index 79212d91285bca72b0ff85f28aaccd2e803ac092..33a03cffe072fe2466c9df30ad47e9c58b0eea7c 100644 > --- a/samples/vfs/.gitignore > +++ b/samples/vfs/.gitignore > @@ -1,3 +1,4 @@ > # SPDX-License-Identifier: GPL-2.0-only > /test-fsmount > /test-statx > +/mountinfo > diff --git a/samples/vfs/Makefile b/samples/vfs/Makefile > index 6377a678134acf0d682151d751d2f5042dbf5e0a..fb9bb33fdc751556e806aa897f0dbd48f7e3a4d8 100644 > --- a/samples/vfs/Makefile > +++ b/samples/vfs/Makefile > @@ -1,4 +1,4 @@ > # SPDX-License-Identifier: GPL-2.0-only > -userprogs-always-y += test-fsmount test-statx > +userprogs-always-y += test-fsmount test-statx mountinfo > > userccflags += -I usr/include > diff --git a/samples/vfs/mountinfo.c b/samples/vfs/mountinfo.c > new file mode 100644 > index 0000000000000000000000000000000000000000..7f430835dd7fb1a3d87d98cad00c619dbb5c6f70 > --- /dev/null > +++ b/samples/vfs/mountinfo.c > @@ -0,0 +1,271 @@ > +// SPDX-License-Identifier: GPL-2.0-or-later > + > +/* > + * Use pidfds, nsfds, listmount() and statmount() mimic the > + * contents of /proc/self/mountinfo. > + */ > +#define _GNU_SOURCE > +#include <stdio.h> > +#include <stdint.h> > +#include <sys/ioctl.h> > +#include <sys/syscall.h> > +#include <linux/pidfd.h> > +#include <linux/mount.h> > +#include <linux/nsfs.h> > +#include <unistd.h> > +#include <alloca.h> > +#include <getopt.h> > +#include <stdlib.h> > +#include <stdbool.h> > +#include <errno.h> > + > +/* max mounts per listmount call */ > +#define MAXMOUNTS 1024 > + > +/* size of struct statmount (including trailing string buffer) */ > +#define STATMOUNT_BUFSIZE 4096 > + > +static bool ext_format; > + > +/* > + * There are no bindings in glibc for listmount() and statmount() (yet), > + * make our own here. > + */ > +static int statmount(uint64_t mnt_id, uint64_t mnt_ns_id, uint64_t mask, > + struct statmount *buf, size_t bufsize, > + unsigned int flags) > +{ > + struct mnt_id_req req = { > + .size = MNT_ID_REQ_SIZE_VER0, > + .mnt_id = mnt_id, > + .param = mask, > + }; > + > + if (mnt_ns_id) { > + req.size = MNT_ID_REQ_SIZE_VER1; > + req.mnt_ns_id = mnt_ns_id; > + } > + > + return syscall(__NR_statmount, &req, buf, bufsize, flags); > +} > + > +static ssize_t listmount(uint64_t mnt_id, uint64_t mnt_ns_id, > + uint64_t last_mnt_id, uint64_t list[], size_t num, > + unsigned int flags) > +{ > + struct mnt_id_req req = { > + .size = MNT_ID_REQ_SIZE_VER0, > + .mnt_id = mnt_id, > + .param = last_mnt_id, > + }; > + > + if (mnt_ns_id) { > + req.size = MNT_ID_REQ_SIZE_VER1; > + req.mnt_ns_id = mnt_ns_id; > + } > + > + return syscall(__NR_listmount, &req, list, num, flags); > +} > + > +static void show_mnt_attrs(uint64_t flags) > +{ > + printf("%s", flags & MOUNT_ATTR_RDONLY ? "ro" : "rw"); > + > + if (flags & MOUNT_ATTR_NOSUID) > + printf(",nosuid"); > + if (flags & MOUNT_ATTR_NODEV) > + printf(",nodev"); > + if (flags & MOUNT_ATTR_NOEXEC) > + printf(",noexec"); > + > + switch (flags & MOUNT_ATTR__ATIME) { > + case MOUNT_ATTR_RELATIME: > + printf(",relatime"); > + break; > + case MOUNT_ATTR_NOATIME: > + printf(",noatime"); > + break; > + case MOUNT_ATTR_STRICTATIME: > + /* print nothing */ > + break; > + } > + > + if (flags & MOUNT_ATTR_NOSYMFOLLOW) > + printf(",nosymfollow"); > + if (flags & MOUNT_ATTR_IDMAP) > + printf(",idmapped"); > +} > + > +static void show_propagation(struct statmount *sm) > +{ > + if (sm->mnt_propagation & MS_SHARED) > + printf(" shared:%llu", sm->mnt_peer_group); > + if (sm->mnt_propagation & MS_SLAVE) { > + printf(" master:%llu", sm->mnt_master); > + if (sm->mnt_master) > + printf(" propagate_from:%llu", sm->propagate_from); > + } > + if (sm->mnt_propagation & MS_UNBINDABLE) > + printf(" unbindable"); > +} > + > +static void show_sb_flags(uint64_t flags) > +{ > + printf("%s", flags & MS_RDONLY ? "ro" : "rw"); > + if (flags & MS_SYNCHRONOUS) > + printf(",sync"); > + if (flags & MS_DIRSYNC) > + printf(",dirsync"); > + if (flags & MS_MANDLOCK) > + printf(",mand"); > + if (flags & MS_LAZYTIME) > + printf(",lazytime"); > +} > + > +static int dump_mountinfo(uint64_t mnt_id, uint64_t mnt_ns_id) > +{ > + int ret; > + struct statmount *buf = alloca(STATMOUNT_BUFSIZE); > + const uint64_t mask = STATMOUNT_SB_BASIC | STATMOUNT_MNT_BASIC | > + STATMOUNT_PROPAGATE_FROM | STATMOUNT_FS_TYPE | > + STATMOUNT_MNT_ROOT | STATMOUNT_MNT_POINT | > + STATMOUNT_MNT_OPTS | STATMOUNT_FS_SUBTYPE | > + STATMOUNT_SB_SOURCE; > + > + ret = statmount(mnt_id, mnt_ns_id, mask, buf, STATMOUNT_BUFSIZE, 0); > + if (ret < 0) { > + perror("statmount"); > + return 1; > + } > + > + if (ext_format) > + printf("0x%lx 0x%lx 0x%llx ", mnt_ns_id, mnt_id, buf->mnt_parent_id); > + > + printf("%u %u %u:%u %s %s ", buf->mnt_id_old, buf->mnt_parent_id_old, > + buf->sb_dev_major, buf->sb_dev_minor, > + &buf->str[buf->mnt_root], > + &buf->str[buf->mnt_point]); > + show_mnt_attrs(buf->mnt_attr); > + show_propagation(buf); > + > + printf(" - %s", &buf->str[buf->fs_type]); > + if (buf->mask & STATMOUNT_FS_SUBTYPE) > + printf(".%s", &buf->str[buf->fs_subtype]); > + if (buf->mask & STATMOUNT_SB_SOURCE) > + printf(" %s ", &buf->str[buf->sb_source]); > + else > + printf(" :none "); > + > + show_sb_flags(buf->sb_flags); > + if (buf->mask & STATMOUNT_MNT_OPTS) > + printf(",%s", &buf->str[buf->mnt_opts]); > + printf("\n"); > + return 0; > +} > + > +static int dump_mounts(uint64_t mnt_ns_id) > +{ > + uint64_t mntid[MAXMOUNTS]; > + uint64_t last_mnt_id = 0; > + ssize_t count; > + int i; > + > + /* > + * Get a list of all mntids in mnt_ns_id. If it returns MAXMOUNTS > + * mounts, then go again until we get everything. > + */ > + do { > + count = listmount(LSMT_ROOT, mnt_ns_id, last_mnt_id, mntid, MAXMOUNTS, 0); > + if (count < 0 || count > MAXMOUNTS) { > + errno = count < 0 ? errno : count; > + perror("listmount"); > + return 1; > + } > + > + /* Walk the returned mntids and print info about each */ > + for (i = 0; i < count; ++i) { > + int ret = dump_mountinfo(mntid[i], mnt_ns_id); > + > + if (ret != 0) > + return ret; > + } > + /* Set up last_mnt_id to pick up where we left off */ > + last_mnt_id = mntid[count - 1] + 1; > + } while (count == MAXMOUNTS); > + return 0; > +} > + > +static void usage(const char * const prog) > +{ > + printf("Usage:\n"); > + printf("%s [-e] [-p pid] [-r] [-h]\n", prog); > + printf(" -e: extended format\n"); > + printf(" -h: print usage message\n"); > + printf(" -p: get mount namespace from given pid\n"); > + printf(" -r: recursively print all mounts in all child namespaces\n"); > +} > + > +int main(int argc, char * const *argv) > +{ > + struct mnt_ns_info mni = { .size = MNT_NS_INFO_SIZE_VER0 }; > + int pidfd, mntns, ret, opt; > + pid_t pid = getpid(); > + bool recursive = false; > + > + while ((opt = getopt(argc, argv, "ehp:r")) != -1) { > + switch (opt) { > + case 'e': > + ext_format = true; > + break; > + case 'h': > + usage(argv[0]); > + return 0; > + case 'p': > + pid = atoi(optarg); > + break; > + case 'r': > + recursive = true; > + break; > + } > + } > + > + /* Get a pidfd for pid */ > + pidfd = syscall(SYS_pidfd_open, pid, 0); > + if (pidfd < 0) { > + perror("pidfd_open"); > + return 1; > + } > + > + /* Get the mnt namespace for pidfd */ > + mntns = ioctl(pidfd, PIDFD_GET_MNT_NAMESPACE, NULL); > + if (mntns < 0) { > + perror("PIDFD_GET_MNT_NAMESPACE"); > + return 1; > + } > + close(pidfd); > + > + /* get info about mntns. In particular, the mnt_ns_id */ > + ret = ioctl(mntns, NS_MNT_GET_INFO, &mni); > + if (ret < 0) { > + perror("NS_MNT_GET_INFO"); > + return 1; > + } > + > + do { > + int ret; > + > + ret = dump_mounts(mni.mnt_ns_id); > + if (ret) > + return ret; > + > + if (!recursive) > + break; > + > + /* get the next mntns (and overwrite the old mount ns info) */ > + ret = ioctl(mntns, NS_MNT_GET_NEXT, &mni); > + close(mntns); > + mntns = ret; > + } while (mntns >= 0); > + > + return 0; > +} > > --- > base-commit: 3def14eb3d2e9d452623af64e315605150292aa8 > change-id: 20241112-statmount-77808bc02302 > > Best regards, > -- > Jeff Layton <jlayton@kernel.org> >
On Tue, 12 Nov 2024 at 22:21, Jeff Layton <jlayton@kernel.org> wrote: > + /* Walk the returned mntids and print info about each */ > + for (i = 0; i < count; ++i) { > + int ret = dump_mountinfo(mntid[i], mnt_ns_id); > + > + if (ret != 0) > + return ret; > + } > + /* Set up last_mnt_id to pick up where we left off */ > + last_mnt_id = mntid[count - 1] + 1; The +1 is wrong, see do_listmount(), which already increments the last ID: first = mnt_find_id_at(ns, last_mnt_id + 1); I also have some ideas for "cooked" interfaces that are easier to use. See here: https://lore.kernel.org/all/CAJfpegsMahRZBk2d2vRLgO8ao9QUP28BwtfV1HXp5hoTOH6Rvw@mail.gmail.com/ https://lore.kernel.org/all/CAJfpeguMViqawKfJtM7_M9=m+6WsTcPfa_18t_rM9iuMG096RA@mail.gmail.com/ I can do an incremental patch to add these ideas to this example. Thanks, Miklos
On Wed, 2024-11-13 at 15:06 +0100, Miklos Szeredi wrote: > On Tue, 12 Nov 2024 at 22:21, Jeff Layton <jlayton@kernel.org> wrote: > > > + /* Walk the returned mntids and print info about each */ > > + for (i = 0; i < count; ++i) { > > + int ret = dump_mountinfo(mntid[i], mnt_ns_id); > > + > > + if (ret != 0) > > + return ret; > > + } > > + /* Set up last_mnt_id to pick up where we left off */ > > + last_mnt_id = mntid[count - 1] + 1; > > The +1 is wrong, see do_listmount(), which already increments the last ID: > > first = mnt_find_id_at(ns, last_mnt_id + 1); > Ahh ok. The current listmount(2) manpage says: req.param is used to tell the kernel what mount ID to start the list from. This is useful if multiple calls to listmount(2) are required. This can be set to the last mount ID re‐ turned + 1 in order to resume from a previous spot in the list. I just sent a manpage patch to fix that. > I also have some ideas for "cooked" interfaces that are easier to use. > See here: > > https://lore.kernel.org/all/CAJfpegsMahRZBk2d2vRLgO8ao9QUP28BwtfV1HXp5hoTOH6Rvw@mail.gmail.com/ > https://lore.kernel.org/all/CAJfpeguMViqawKfJtM7_M9=m+6WsTcPfa_18t_rM9iuMG096RA@mail.gmail.com/ > Yeah, those do look nicer for userland. > I can do an incremental patch to add these ideas to this example. > Sure, sounds good.
diff --git a/samples/vfs/.gitignore b/samples/vfs/.gitignore index 79212d91285bca72b0ff85f28aaccd2e803ac092..33a03cffe072fe2466c9df30ad47e9c58b0eea7c 100644 --- a/samples/vfs/.gitignore +++ b/samples/vfs/.gitignore @@ -1,3 +1,4 @@ # SPDX-License-Identifier: GPL-2.0-only /test-fsmount /test-statx +/mountinfo diff --git a/samples/vfs/Makefile b/samples/vfs/Makefile index 6377a678134acf0d682151d751d2f5042dbf5e0a..fb9bb33fdc751556e806aa897f0dbd48f7e3a4d8 100644 --- a/samples/vfs/Makefile +++ b/samples/vfs/Makefile @@ -1,4 +1,4 @@ # SPDX-License-Identifier: GPL-2.0-only -userprogs-always-y += test-fsmount test-statx +userprogs-always-y += test-fsmount test-statx mountinfo userccflags += -I usr/include diff --git a/samples/vfs/mountinfo.c b/samples/vfs/mountinfo.c new file mode 100644 index 0000000000000000000000000000000000000000..7f430835dd7fb1a3d87d98cad00c619dbb5c6f70 --- /dev/null +++ b/samples/vfs/mountinfo.c @@ -0,0 +1,271 @@ +// SPDX-License-Identifier: GPL-2.0-or-later + +/* + * Use pidfds, nsfds, listmount() and statmount() mimic the + * contents of /proc/self/mountinfo. + */ +#define _GNU_SOURCE +#include <stdio.h> +#include <stdint.h> +#include <sys/ioctl.h> +#include <sys/syscall.h> +#include <linux/pidfd.h> +#include <linux/mount.h> +#include <linux/nsfs.h> +#include <unistd.h> +#include <alloca.h> +#include <getopt.h> +#include <stdlib.h> +#include <stdbool.h> +#include <errno.h> + +/* max mounts per listmount call */ +#define MAXMOUNTS 1024 + +/* size of struct statmount (including trailing string buffer) */ +#define STATMOUNT_BUFSIZE 4096 + +static bool ext_format; + +/* + * There are no bindings in glibc for listmount() and statmount() (yet), + * make our own here. + */ +static int statmount(uint64_t mnt_id, uint64_t mnt_ns_id, uint64_t mask, + struct statmount *buf, size_t bufsize, + unsigned int flags) +{ + struct mnt_id_req req = { + .size = MNT_ID_REQ_SIZE_VER0, + .mnt_id = mnt_id, + .param = mask, + }; + + if (mnt_ns_id) { + req.size = MNT_ID_REQ_SIZE_VER1; + req.mnt_ns_id = mnt_ns_id; + } + + return syscall(__NR_statmount, &req, buf, bufsize, flags); +} + +static ssize_t listmount(uint64_t mnt_id, uint64_t mnt_ns_id, + uint64_t last_mnt_id, uint64_t list[], size_t num, + unsigned int flags) +{ + struct mnt_id_req req = { + .size = MNT_ID_REQ_SIZE_VER0, + .mnt_id = mnt_id, + .param = last_mnt_id, + }; + + if (mnt_ns_id) { + req.size = MNT_ID_REQ_SIZE_VER1; + req.mnt_ns_id = mnt_ns_id; + } + + return syscall(__NR_listmount, &req, list, num, flags); +} + +static void show_mnt_attrs(uint64_t flags) +{ + printf("%s", flags & MOUNT_ATTR_RDONLY ? "ro" : "rw"); + + if (flags & MOUNT_ATTR_NOSUID) + printf(",nosuid"); + if (flags & MOUNT_ATTR_NODEV) + printf(",nodev"); + if (flags & MOUNT_ATTR_NOEXEC) + printf(",noexec"); + + switch (flags & MOUNT_ATTR__ATIME) { + case MOUNT_ATTR_RELATIME: + printf(",relatime"); + break; + case MOUNT_ATTR_NOATIME: + printf(",noatime"); + break; + case MOUNT_ATTR_STRICTATIME: + /* print nothing */ + break; + } + + if (flags & MOUNT_ATTR_NOSYMFOLLOW) + printf(",nosymfollow"); + if (flags & MOUNT_ATTR_IDMAP) + printf(",idmapped"); +} + +static void show_propagation(struct statmount *sm) +{ + if (sm->mnt_propagation & MS_SHARED) + printf(" shared:%llu", sm->mnt_peer_group); + if (sm->mnt_propagation & MS_SLAVE) { + printf(" master:%llu", sm->mnt_master); + if (sm->mnt_master) + printf(" propagate_from:%llu", sm->propagate_from); + } + if (sm->mnt_propagation & MS_UNBINDABLE) + printf(" unbindable"); +} + +static void show_sb_flags(uint64_t flags) +{ + printf("%s", flags & MS_RDONLY ? "ro" : "rw"); + if (flags & MS_SYNCHRONOUS) + printf(",sync"); + if (flags & MS_DIRSYNC) + printf(",dirsync"); + if (flags & MS_MANDLOCK) + printf(",mand"); + if (flags & MS_LAZYTIME) + printf(",lazytime"); +} + +static int dump_mountinfo(uint64_t mnt_id, uint64_t mnt_ns_id) +{ + int ret; + struct statmount *buf = alloca(STATMOUNT_BUFSIZE); + const uint64_t mask = STATMOUNT_SB_BASIC | STATMOUNT_MNT_BASIC | + STATMOUNT_PROPAGATE_FROM | STATMOUNT_FS_TYPE | + STATMOUNT_MNT_ROOT | STATMOUNT_MNT_POINT | + STATMOUNT_MNT_OPTS | STATMOUNT_FS_SUBTYPE | + STATMOUNT_SB_SOURCE; + + ret = statmount(mnt_id, mnt_ns_id, mask, buf, STATMOUNT_BUFSIZE, 0); + if (ret < 0) { + perror("statmount"); + return 1; + } + + if (ext_format) + printf("0x%lx 0x%lx 0x%llx ", mnt_ns_id, mnt_id, buf->mnt_parent_id); + + printf("%u %u %u:%u %s %s ", buf->mnt_id_old, buf->mnt_parent_id_old, + buf->sb_dev_major, buf->sb_dev_minor, + &buf->str[buf->mnt_root], + &buf->str[buf->mnt_point]); + show_mnt_attrs(buf->mnt_attr); + show_propagation(buf); + + printf(" - %s", &buf->str[buf->fs_type]); + if (buf->mask & STATMOUNT_FS_SUBTYPE) + printf(".%s", &buf->str[buf->fs_subtype]); + if (buf->mask & STATMOUNT_SB_SOURCE) + printf(" %s ", &buf->str[buf->sb_source]); + else + printf(" :none "); + + show_sb_flags(buf->sb_flags); + if (buf->mask & STATMOUNT_MNT_OPTS) + printf(",%s", &buf->str[buf->mnt_opts]); + printf("\n"); + return 0; +} + +static int dump_mounts(uint64_t mnt_ns_id) +{ + uint64_t mntid[MAXMOUNTS]; + uint64_t last_mnt_id = 0; + ssize_t count; + int i; + + /* + * Get a list of all mntids in mnt_ns_id. If it returns MAXMOUNTS + * mounts, then go again until we get everything. + */ + do { + count = listmount(LSMT_ROOT, mnt_ns_id, last_mnt_id, mntid, MAXMOUNTS, 0); + if (count < 0 || count > MAXMOUNTS) { + errno = count < 0 ? errno : count; + perror("listmount"); + return 1; + } + + /* Walk the returned mntids and print info about each */ + for (i = 0; i < count; ++i) { + int ret = dump_mountinfo(mntid[i], mnt_ns_id); + + if (ret != 0) + return ret; + } + /* Set up last_mnt_id to pick up where we left off */ + last_mnt_id = mntid[count - 1] + 1; + } while (count == MAXMOUNTS); + return 0; +} + +static void usage(const char * const prog) +{ + printf("Usage:\n"); + printf("%s [-e] [-p pid] [-r] [-h]\n", prog); + printf(" -e: extended format\n"); + printf(" -h: print usage message\n"); + printf(" -p: get mount namespace from given pid\n"); + printf(" -r: recursively print all mounts in all child namespaces\n"); +} + +int main(int argc, char * const *argv) +{ + struct mnt_ns_info mni = { .size = MNT_NS_INFO_SIZE_VER0 }; + int pidfd, mntns, ret, opt; + pid_t pid = getpid(); + bool recursive = false; + + while ((opt = getopt(argc, argv, "ehp:r")) != -1) { + switch (opt) { + case 'e': + ext_format = true; + break; + case 'h': + usage(argv[0]); + return 0; + case 'p': + pid = atoi(optarg); + break; + case 'r': + recursive = true; + break; + } + } + + /* Get a pidfd for pid */ + pidfd = syscall(SYS_pidfd_open, pid, 0); + if (pidfd < 0) { + perror("pidfd_open"); + return 1; + } + + /* Get the mnt namespace for pidfd */ + mntns = ioctl(pidfd, PIDFD_GET_MNT_NAMESPACE, NULL); + if (mntns < 0) { + perror("PIDFD_GET_MNT_NAMESPACE"); + return 1; + } + close(pidfd); + + /* get info about mntns. In particular, the mnt_ns_id */ + ret = ioctl(mntns, NS_MNT_GET_INFO, &mni); + if (ret < 0) { + perror("NS_MNT_GET_INFO"); + return 1; + } + + do { + int ret; + + ret = dump_mounts(mni.mnt_ns_id); + if (ret) + return ret; + + if (!recursive) + break; + + /* get the next mntns (and overwrite the old mount ns info) */ + ret = ioctl(mntns, NS_MNT_GET_NEXT, &mni); + close(mntns); + mntns = ret; + } while (mntns >= 0); + + return 0; +}
Add a new "mountinfo" sample userland program that demonstrates how to use statmount() and listmount() to get at the same info that /proc/pid/mountinfo provides. The output of the program tries to mimic the mountinfo procfile contents. With the -p flag, it can be pointed at an arbitrary pid to print out info about its mount namespace. With the -r flag it will attempt to walk all of the namespaces under the pid's mount namespace and dump out mount info from all of them. Signed-off-by: Jeff Layton <jlayton@kernel.org> --- We had some recent queries internally asking how to use the new statmount() and listmount() interfaces. I was doing some other work in this area, so I whipped up this tool. My hope is that this will represent something of a "rosetta stone" for how to translate between mountinfo and statmount(), and an example for other people looking to use the new interfaces. It may also be possible to use this as the basis for a statmount() testcase. We can call this program, and compare its output to the mountinfo file. --- samples/vfs/.gitignore | 1 + samples/vfs/Makefile | 2 +- samples/vfs/mountinfo.c | 271 ++++++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 273 insertions(+), 1 deletion(-) --- base-commit: 3def14eb3d2e9d452623af64e315605150292aa8 change-id: 20241112-statmount-77808bc02302 Best regards,