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 | 193 ++++++++++++++++++++++++
1 file changed, 193 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..629731f75f6
--- /dev/null
+++ b/compat/fsmonitor/fsm-path-utils-linux.c
@@ -0,0 +1,193 @@
+#include "fsmonitor.h"
+#include "fsmonitor-path-utils.h"
+#include <errno.h>
+#include <mntent.h>
+#include <sys/mount.h>
+#include <sys/vfs.h>
+#include <sys/statvfs.h>
+
+static int is_remote_fs(const char *path) {
+ struct statfs fs;
+
+ if (statfs(path, &fs)) {
+ error_errno(_("statfs('%s') failed"), path);
+ return -1;
+ }
+
+ switch (fs.f_type) {
+ case 0x61636673: /* ACFS */
+ case 0x5346414F: /* AFS */
+ case 0x00C36400: /* CEPH */
+ case 0xFF534D42: /* CIFS */
+ case 0x73757245: /* CODA */
+ case 0x19830326: /* FHGFS */
+ case 0x1161970: /* GFS */
+ case 0x47504653: /* GPFS */
+ case 0x013111A8: /* IBRIX */
+ case 0x6B414653: /* KAFS */
+ case 0x0BD00BD0: /* LUSTRE */
+ case 0x564C: /* NCP */
+ case 0x6969: /* NFS */
+ case 0x6E667364: /* NFSD */
+ case 0x7461636f: /* OCFS2 */
+ case 0xAAD7AAEA: /* PANFS */
+ case 0x517B: /* SMB */
+ case 0xBEEFDEAD: /* SNFS */
+ case 0xFE534D42: /* SMB2 */
+ case 0xBACBACBC: /* VMHGFS */
+ case 0xA501FCF5: /* VXFS */
+ return 1;
+ default:
+ break;
+ }
+
+ return 0;
+}
+
+static int find_mount(const char *path, const struct statvfs *fs,
+ struct mntent *entry)
+{
+ const char *const mounts = "/proc/mounts";
+ char *rp = real_pathdup(path, 1);
+ struct mntent *ment = NULL;
+ struct statvfs mntfs;
+ FILE *fp;
+ int found = 0;
+ int dlen, plen, flen = 0;
+
+ entry->mnt_fsname = NULL;
+ entry->mnt_dir = NULL;
+ entry->mnt_type = NULL;
+
+ fp = setmntent(mounts, "r");
+ if (!fp) {
+ free(rp);
+ 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);
+ free(rp);
+ 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;
+ /*
+ * look for the longest prefix (including root)
+ */
+ if (dlen > flen &&
+ ((dlen == 1 && ment->mnt_dir[0] == '/') ||
+ (!rp[dlen] || rp[dlen] == '/'))) {
+ flen = dlen;
+ found = 1;
+
+ /*
+ * 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().
+ */
+ free(entry->mnt_fsname);
+ free(entry->mnt_dir);
+ free(entry->mnt_type);
+ entry->mnt_fsname = xstrdup(ment->mnt_fsname);
+ entry->mnt_dir = xstrdup(ment->mnt_dir);
+ entry->mnt_type = xstrdup(ment->mnt_type);
+ }
+ }
+ }
+ endmntent(fp);
+ free(rp);
+
+ if (!found)
+ return -1;
+
+ return 0;
+}
+
+int fsmonitor__get_fs_info(const char *path, struct fs_info *fs_info)
+{
+ struct mntent entry;
+ struct statvfs fs;
+
+ fs_info->is_remote = -1;
+ fs_info->typename = NULL;
+
+ if (statvfs(path, &fs))
+ return error_errno(_("statvfs('%s') failed"), path);
+
+ if (find_mount(path, &fs, &entry) < 0) {
+ free(entry.mnt_fsname);
+ free(entry.mnt_dir);
+ free(entry.mnt_type);
+ return -1;
+ }
+
+ trace_printf_key(&trace_fsmonitor,
+ "statvfs('%s') [flags 0x%08lx] '%s' '%s'",
+ path, fs.f_flag, entry.mnt_type, entry.mnt_fsname);
+
+ fs_info->is_remote = is_remote_fs(entry.mnt_dir);
+ fs_info->typename = xstrdup(entry.mnt_fsname);
+ free(entry.mnt_fsname);
+ free(entry.mnt_dir);
+ free(entry.mnt_type);
+
+ if (fs_info->is_remote < 0)
+ return -1;
+
+ 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)) {
+ free(fs.typename);
+ 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
