From 811de54f8952f780c8f15c794be37cd326616cd1 Mon Sep 17 00:00:00 2001
From: TJ Saunders <tj@castaglia.org>
Date: Sat, 30 Mar 2024 12:05:00 -0700
Subject: [PATCH] Provide a `realpath(3)` implementation, for use by other
 modules, using the new FSIO API for such functionality.

---
 fsio.c         | 27 ++++++++++++++++++++++++++-
 fsio.h         |  3 ++-
 mod_vroot.c    |  5 ++++-
 mod_vroot.h.in |  4 ++--
 4 files changed, 34 insertions(+), 5 deletions(-)

diff --git a/fsio.c b/fsio.c
index 2e80b9d..031ed33 100644
--- a/fsio.c
+++ b/fsio.c
@@ -1,6 +1,6 @@
 /*
  * ProFTPD: mod_vroot FSIO API
- * Copyright (c) 2002-2021 TJ Saunders
+ * Copyright (c) 2002-2024 TJ Saunders
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -643,6 +643,31 @@ int vroot_fsio_utimes(pr_fs_t *fs, const char *utimes_path,
   return res;
 }
 
+const char *vroot_fsio_realpath(pr_fs_t *fs, pool *p, const char *path) {
+  const char *res = NULL;
+  int xerrno;
+  char vpath[PR_TUNABLE_PATH_MAX + 1], *real_path = NULL;
+  pool *tmp_pool = NULL;
+
+  tmp_pool = make_sub_pool(p);
+  pr_pool_tag(tmp_pool, "VRoot FSIO realpath pool");
+
+  real_path = vroot_realpath(p, path, VROOT_REALPATH_FL_ABS_PATH);
+
+  if (vroot_path_lookup(NULL, vpath, sizeof(vpath)-1, real_path, 0, NULL) < 0) {
+    xerrno = errno;
+
+    destroy_pool(tmp_pool);
+    errno = xerrno;
+    return NULL;
+  }
+
+  destroy_pool(tmp_pool);
+
+  res = pstrdup(p, vpath);
+  return res;
+}
+
 static struct dirent *vroot_dent = NULL;
 static size_t vroot_dentsz = 0;
 
diff --git a/fsio.h b/fsio.h
index 3de324c..8ef9158 100644
--- a/fsio.h
+++ b/fsio.h
@@ -1,6 +1,6 @@
 /*
  * ProFTPD - mod_vroot FSIO API
- * Copyright (c) 2016 TJ Saunders
+ * Copyright (c) 2016-2024 TJ Saunders
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -43,6 +43,7 @@ int vroot_fsio_lchown(pr_fs_t *fs, const char *path, uid_t uid, gid_t gid);
 int vroot_fsio_chroot(pr_fs_t *fs, const char *path);
 int vroot_fsio_chdir(pr_fs_t *fs, const char *path);
 int vroot_fsio_utimes(pr_fs_t *fs, const char *path, struct timeval *tvs);
+const char *vroot_fsio_realpath(pr_fs_t *fs, pool *p, const char *path);
 void *vroot_fsio_opendir(pr_fs_t *fs, const char *path);
 struct dirent *vroot_fsio_readdir(pr_fs_t *fs, void *dirh);
 int vroot_fsio_closedir(pr_fs_t *fs, void *dirh);
diff --git a/mod_vroot.c b/mod_vroot.c
index 79422ba..684d725 100644
--- a/mod_vroot.c
+++ b/mod_vroot.c
@@ -1,7 +1,7 @@
 /*
  * ProFTPD: mod_vroot -- a module implementing a virtual chroot capability
  *                       via the FSIO API
- * Copyright (c) 2002-2022 TJ Saunders
+ * Copyright (c) 2002-2024 TJ Saunders
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -587,6 +587,9 @@ static void vroot_chroot_ev(const void *event_data, void *user_data) {
 #if PROFTPD_VERSION_NUMBER >= 0x0001030407
   fs->lchown = vroot_fsio_lchown;
 #endif /* ProFTPD 1.3.4c or later */
+#if PROFTPD_VERSION_NUMBER >= 0x0001030903
+  fs->realpath = vroot_fsio_realpath;
+#endif /* ProFTPD 1.3.9rc3 or later */
   fs->chdir = vroot_fsio_chdir;
   fs->chroot = vroot_fsio_chroot;
   fs->utimes = vroot_fsio_utimes;
diff --git a/mod_vroot.h.in b/mod_vroot.h.in
index 0a1b37e..bf8ccd7 100644
--- a/mod_vroot.h.in
+++ b/mod_vroot.h.in
@@ -1,6 +1,6 @@
 /*
  * ProFTPD - mod_vroot
- * Copyright (c) 2016-2022 TJ Saunders
+ * Copyright (c) 2016-2024 TJ Saunders
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -27,7 +27,7 @@
 
 #include "conf.h"
 
-#define MOD_VROOT_VERSION			"mod_vroot/0.9.11"
+#define MOD_VROOT_VERSION			"mod_vroot/0.9.12"
 
 /* Make sure the version of proftpd is as necessary. */
 #if PROFTPD_VERSION_NUMBER < 0x0001030602