From 7d3cc24dec12554d58f65db748a98c3f8bcba71b Mon Sep 17 00:00:00 2001
From: Dana Conrad <dconrad@fastmail.com>
Date: Thu, 5 Dec 2024 01:54:01 +0000
Subject: [PATCH] FS#13519: multivolume: Ensure absolute paths get drive
 designation

Change-Id: I8419af670ca101b11bba29d9fd577f21fa22fd42
---
 apps/playlist.c             |  4 +++-
 firmware/common/pathfuncs.c | 37 +++++++++++++++++++++++++++++++++----
 2 files changed, 36 insertions(+), 5 deletions(-)

diff --git a/apps/playlist.c b/apps/playlist.c
index 465ebb88a0..00343e839e 100644
--- a/apps/playlist.c
+++ b/apps/playlist.c
@@ -70,7 +70,7 @@
       flushed to disk when required.
  */
 
-//#define LOGF_ENABLE
+// #define LOGF_ENABLE
 #include <stdio.h>
 #include <stdlib.h>
 #include <ctype.h>
@@ -592,6 +592,8 @@ static ssize_t format_track_path(char *dest, char *src, int buf_length,
         dlen = -1u;
     }
 
+    logf("dir: %s", dir);
+
     len = path_append_ex(dest, dir, dlen, src, buf_length);
     if (len >= (size_t)buf_length)
         return -1; /* buffer too small */
diff --git a/firmware/common/pathfuncs.c b/firmware/common/pathfuncs.c
index b5e5ecb0cf..ba815e3307 100644
--- a/firmware/common/pathfuncs.c
+++ b/firmware/common/pathfuncs.c
@@ -27,6 +27,9 @@
 #include "file_internal.h"
 #include "debug.h"
 
+// #define LOGF_ENABLE
+#include "logf.h"
+
 #ifdef HAVE_MULTIVOLUME
 #include "storage.h"
 
@@ -521,10 +524,36 @@ size_t path_append_ex(char *buf, const char *basepath, size_t basepath_max,
 
     if (path_is_absolute(component)) /* starts with a '/' path separator */
     {
-        /* 'component' is absolute; replace all */
-        basepath = component;
-        component = "";
-        basepath_max = -1u;
+        #if defined(HAVE_MULTIVOLUME)
+            const char *baseend;
+            /* our component doesn't appear to have a drive/volume */
+            if (path_strip_volume(component, &baseend, false) == ROOT_VOLUME)
+            {
+                /* find the basepath's drive/volume name, if it has one.
+                 * ensure basepath is not NULL, that causes a crash on sim */
+                if (basepath != NULL && path_strip_volume(basepath, &baseend, false) != ROOT_VOLUME)
+                {
+                    basepath_max = baseend - basepath;
+                    /* strip leading separators from component */
+                    while (*component == PATH_SEPCH)
+                        component++;
+                } else {
+                    /* component is absolute with no drive/volume, but basepath doesn't 
+                     * have a volume either... we must be on root volume */
+                    basepath = component;
+                    component = "";
+                    basepath_max = -1u;
+                }
+            }
+            /* else component likely already has drive/volume name */
+            else
+        #endif
+            {
+                /* 'component' is absolute; replace all */
+                basepath = component;
+                component = "";
+                basepath_max = -1u;
+            }
     }
 
     /* if basepath is not null or empty, buffer contents are replaced,