From: Eric DeCosta <edecosta@xxxxxxxxxxxxx> Compare the given path to the mounted filesystems. Find the mount that is the longest prefix of the path (if any) and determine if that mount is on a local or remote filesystem. Signed-off-by: Eric DeCosta <edecosta@xxxxxxxxxxxxx> --- compat/fsmonitor/fsm-path-utils-linux.c | 169 ++++++++++++++++++++++++ 1 file changed, 169 insertions(+) create mode 100644 compat/fsmonitor/fsm-path-utils-linux.c diff --git a/compat/fsmonitor/fsm-path-utils-linux.c b/compat/fsmonitor/fsm-path-utils-linux.c new file mode 100644 index 00000000000..039f044b670 --- /dev/null +++ b/compat/fsmonitor/fsm-path-utils-linux.c @@ -0,0 +1,169 @@ +#include "fsmonitor.h" +#include "fsmonitor-path-utils.h" +#include <errno.h> +#include <mntent.h> +#include <sys/mount.h> +#include <sys/statvfs.h> + +/* + * https://github.com/coreutils/gnulib/blob/master/lib/mountlist.c + */ +#ifndef ME_REMOTE +/* A file system is "remote" if its Fs_name contains a ':' + or if (it is of type (smbfs or cifs) and its Fs_name starts with '//') + or if it is of any other of the listed types + or Fs_name is equal to "-hosts" (used by autofs to mount remote fs). + "VM" file systems like prl_fs or vboxsf are not considered remote here. */ +# define ME_REMOTE(Fs_name, Fs_type) \ + (strchr (Fs_name, ':') != NULL \ + || ((Fs_name)[0] == '/' \ + && (Fs_name)[1] == '/' \ + && (strcmp (Fs_type, "smbfs") == 0 \ + || strcmp (Fs_type, "smb3") == 0 \ + || strcmp (Fs_type, "cifs") == 0)) \ + || strcmp (Fs_type, "acfs") == 0 \ + || strcmp (Fs_type, "afs") == 0 \ + || strcmp (Fs_type, "coda") == 0 \ + || strcmp (Fs_type, "auristorfs") == 0 \ + || strcmp (Fs_type, "fhgfs") == 0 \ + || strcmp (Fs_type, "gpfs") == 0 \ + || strcmp (Fs_type, "ibrix") == 0 \ + || strcmp (Fs_type, "ocfs2") == 0 \ + || strcmp (Fs_type, "vxfs") == 0 \ + || strcmp ("-hosts", Fs_name) == 0) +#endif + +static int find_mount(const char *path, const struct statvfs *fs, + struct mntent *ent) +{ + const char *const mounts = "/proc/mounts"; + const char *rp = real_pathdup(path, 1); + struct mntent *ment = NULL; + struct statvfs mntfs; + FILE *fp; + int found = 0; + int dlen, plen, flen = 0; + + ent->mnt_fsname = NULL; + ent->mnt_dir = NULL; + ent->mnt_type = NULL; + + fp = setmntent(mounts, "r"); + if (!fp) { + error_errno(_("setmntent('%s') failed"), mounts); + return -1; + } + + plen = strlen(rp); + + /* read all the mount information and compare to path */ + while ((ment = getmntent(fp)) != NULL) { + if (statvfs(ment->mnt_dir, &mntfs)) { + switch (errno) { + case EPERM: + case ESRCH: + case EACCES: + continue; + default: + error_errno(_("statvfs('%s') failed"), ment->mnt_dir); + endmntent(fp); + return -1; + } + } + + /* is mount on the same filesystem and is a prefix of the path */ + if ((fs->f_fsid == mntfs.f_fsid) && + !strncmp(ment->mnt_dir, rp, strlen(ment->mnt_dir))) { + dlen = strlen(ment->mnt_dir); + if (dlen > plen) + continue; + /* + * root is always a potential match; otherwise look for + * directory prefix + */ + if ((dlen == 1 && ment->mnt_dir[0] == '/') || + (dlen > flen && (!rp[dlen] || rp[dlen] == '/'))) { + flen = dlen; + /* + * https://man7.org/linux/man-pages/man3/getmntent.3.html + * + * The pointer points to a static area of memory which is + * overwritten by subsequent calls to getmntent(). + */ + found = 1; + free(ent->mnt_fsname); + free(ent->mnt_dir); + free(ent->mnt_type); + ent->mnt_fsname = xstrdup(ment->mnt_fsname); + ent->mnt_dir = xstrdup(ment->mnt_dir); + ent->mnt_type = xstrdup(ment->mnt_type); + } + } + } + endmntent(fp); + + if (!found) + return -1; + + return 0; +} + +int fsmonitor__get_fs_info(const char *path, struct fs_info *fs_info) +{ + struct mntent ment; + struct statvfs fs; + + if (statvfs(path, &fs)) + return error_errno(_("statvfs('%s') failed"), path); + + + if (find_mount(path, &fs, &ment) < 0) { + free(ment.mnt_fsname); + free(ment.mnt_dir); + free(ment.mnt_type); + return -1; + } + + trace_printf_key(&trace_fsmonitor, + "statvfs('%s') [flags 0x%08lx] '%s' '%s'", + path, fs.f_flag, ment.mnt_type, ment.mnt_fsname); + + fs_info->is_remote = ME_REMOTE(ment.mnt_fsname, ment.mnt_type); + fs_info->typename = ment.mnt_fsname; + free(ment.mnt_dir); + free(ment.mnt_type); + + trace_printf_key(&trace_fsmonitor, + "'%s' is_remote: %d", + path, fs_info->is_remote); + return 0; +} + +int fsmonitor__is_fs_remote(const char *path) +{ + struct fs_info fs; + + if (fsmonitor__get_fs_info(path, &fs)) + return -1; + + free(fs.typename); + + return fs.is_remote; +} + +/* + * No-op for now. + */ +int fsmonitor__get_alias(const char *path, struct alias_info *info) +{ + return 0; +} + +/* + * No-op for now. + */ +char *fsmonitor__resolve_alias(const char *path, + const struct alias_info *info) +{ + return NULL; +} -- gitgitgadget
