Platform (Windows): adds implementation of POSIX readlink(2) and realpath(3)

CarterLi · CarterLi · commit 4e234c52a32d · 2026-03-17T17:59:24.000+08:00
diff --git a/src/common/impl/FFPlatform_windows.c b/src/common/impl/FFPlatform_windows.c
@@ -28,7 +28,7 @@ static void getExePath(FFPlatform* platform)
         NULL);
     if (hPath != INVALID_HANDLE_VALUE)
     {
-        DWORD len = GetFinalPathNameByHandleW(hPath, exePathW, MAX_PATH, FILE_NAME_OPENED);
+        DWORD len = GetFinalPathNameByHandleW(hPath, exePathW, MAX_PATH, FILE_NAME_NORMALIZED);
         if (len > 0 && len < MAX_PATH)
         {
             ffStrbufSetNWS(&platform->exePath, len, exePathW);
diff --git a/src/common/impl/path.c b/src/common/impl/path.c
@@ -1,6 +1,6 @@
 #include "common/path.h"
 #include "common/io.h"
-#include "common/stringUtils.h"
+#include "common/arrayUtils.h"
 
 #if !_WIN32
 const char* ffFindExecutableInPath(const char* name, FFstrbuf* result)
@@ -49,6 +49,9 @@ const char* ffFindExecutableInPath(const char* name, FFstrbuf* result)
 }
 #else
 #include <windows.h>
+#include <winioctl.h>
+#include <errno.h>
+#include <stdalign.h>
 
 const char* ffFindExecutableInPath(const char* name, FFstrbuf* result)
 {
@@ -62,4 +65,260 @@ const char* ffFindExecutableInPath(const char* name, FFstrbuf* result)
     ffStrbufSetS(result, buffer);
     return NULL;
 }
+
+static inline int winerr2Errno(DWORD err)
+{
+    switch (err)
+    {
+        case ERROR_FILE_NOT_FOUND:
+        case ERROR_PATH_NOT_FOUND:
+        case ERROR_INVALID_NAME:
+            return ENOENT;
+        case ERROR_ACCESS_DENIED:
+        case ERROR_SHARING_VIOLATION:
+        case ERROR_LOCK_VIOLATION:
+            return EACCES;
+        case ERROR_BUFFER_OVERFLOW:
+        case ERROR_INSUFFICIENT_BUFFER:
+            return ENAMETOOLONG;
+        case ERROR_INVALID_PARAMETER:
+        case ERROR_NOT_A_REPARSE_POINT:
+            return EINVAL;
+        default:
+            return EIO;
+    }
+}
+
+char* frealpath(HANDLE hFile, char* resolved_name)
+{
+    if (__builtin_expect(hFile == INVALID_HANDLE_VALUE || !hFile, false))
+    {
+        errno = EINVAL;
+        return NULL;
+    }
+
+    wchar_t resolvedNameW[MAX_PATH + 4]; /* +4 for "\\\\?\\" prefix */
+    DWORD lenW = GetFinalPathNameByHandleW(hFile, resolvedNameW, (DWORD)ARRAY_SIZE(resolvedNameW), FILE_NAME_NORMALIZED);
+
+    if (lenW == 0)
+    {
+        errno = winerr2Errno(GetLastError());
+        return NULL;
+    }
+    if (lenW >= ARRAY_SIZE(resolvedNameW))
+    {
+        errno = E2BIG;
+        return NULL;
+    }
+    lenW++; // Include null terminator
+
+    wchar_t* srcW = resolvedNameW;
+    DWORD srcLenW = lenW;
+
+    if (srcLenW >= 8 && wcsncmp(resolvedNameW, L"\\\\?\\UNC\\", 8) == 0)
+    {
+        /* Convert "\\?\UNC\server\share" to "\\server\share" */
+        srcW += 6;
+        srcLenW -= 6;
+        *srcW = L'\\';
+    }
+    else if (srcLenW >= 4 && wcsncmp(resolvedNameW, L"\\\\?\\", 4) == 0)
+    {
+        srcW += 4;
+        srcLenW -= 4;
+    }
+
+    if (resolved_name)
+    {
+        ULONG outBytes = 0;
+        if (!NT_SUCCESS(RtlUnicodeToUTF8N(resolved_name, MAX_PATH, &outBytes, srcW, (ULONG)(srcLenW * sizeof(wchar_t)))))
+        {
+            errno = E2BIG;
+            return NULL;
+        }
+
+        if (outBytes > MAX_PATH)
+        {
+            errno = E2BIG;
+            return NULL;
+        }
+
+        return resolved_name;
+    }
+    else
+    {
+        /* UTF-8 worst-case: up to 4 bytes per UTF-16 code unit */
+        char tmp[(MAX_PATH + 4) * 4];
+        ULONG outBytes = 0;
+
+        if (!NT_SUCCESS(RtlUnicodeToUTF8N(tmp, (ULONG)sizeof(tmp), &outBytes, srcW, (ULONG)(srcLenW * sizeof(wchar_t)))))
+        {
+            errno = E2BIG;
+            return NULL;
+        }
+
+        resolved_name = (char*)malloc(outBytes);
+        if (!resolved_name)
+        {
+            errno = ENOMEM;
+            return NULL;
+        }
+
+        memcpy(resolved_name, tmp, outBytes);
+        return resolved_name;
+    }
+
+    return resolved_name;
+}
+
+char* realpath(const char* __restrict file_name, char* __restrict resolved_name)
+{
+    if (!file_name)
+    {
+        errno = EINVAL;
+        return NULL;
+    }
+
+    wchar_t fileNameW[MAX_PATH];
+    ULONG lenBytes = 0;
+
+    if (!NT_SUCCESS(RtlUTF8ToUnicodeN(fileNameW, (ULONG)sizeof(fileNameW), &lenBytes, file_name, (ULONG)strlen(file_name) + 1)))
+    {
+        errno = EINVAL;
+        return NULL;
+    }
+
+    FF_AUTO_CLOSE_FD HANDLE hFile = CreateFileW(
+        fileNameW,
+        0,
+        FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE,
+        NULL,
+        OPEN_EXISTING,
+        FILE_FLAG_BACKUP_SEMANTICS,
+        NULL);
+
+    if (hFile == INVALID_HANDLE_VALUE)
+    {
+        errno = winerr2Errno(GetLastError());
+        return NULL;
+    }
+
+    return frealpath(hFile, resolved_name);
+}
+
+ssize_t freadlink(HANDLE hFile, char* buf, size_t bufsiz)
+{
+    if (__builtin_expect(hFile == INVALID_HANDLE_VALUE || !buf || bufsiz == 0, false))
+    {
+        errno = EINVAL;
+        return -1;
+    }
+
+    alignas(REPARSE_DATA_BUFFER) BYTE reparseBuf[MAXIMUM_REPARSE_DATA_BUFFER_SIZE];
+    DWORD bytesReturned = 0;
+    if (!DeviceIoControl(hFile, FSCTL_GET_REPARSE_POINT, NULL, 0, reparseBuf, (DWORD) sizeof(reparseBuf), &bytesReturned, NULL))
+    {
+        errno = winerr2Errno(GetLastError());
+        return -1;
+    }
+
+    REPARSE_DATA_BUFFER* rp = (REPARSE_DATA_BUFFER*) reparseBuf;
+    const wchar_t* targetW = NULL;
+    USHORT targetBytes = 0;
+
+    if (rp->ReparseTag == IO_REPARSE_TAG_SYMLINK)
+    {
+        if (rp->SymbolicLinkReparseBuffer.PrintNameLength > 0)
+        {
+            targetW = rp->SymbolicLinkReparseBuffer.PathBuffer +
+                (rp->SymbolicLinkReparseBuffer.PrintNameOffset / sizeof(wchar_t));
+            targetBytes = rp->SymbolicLinkReparseBuffer.PrintNameLength;
+        }
+        else
+        {
+            targetW = rp->SymbolicLinkReparseBuffer.PathBuffer +
+                (rp->SymbolicLinkReparseBuffer.SubstituteNameOffset / sizeof(wchar_t));
+            targetBytes = rp->SymbolicLinkReparseBuffer.SubstituteNameLength;
+
+            if (targetBytes >= 8 &&
+                wcsncmp(targetW, L"\\??\\", 4) == 0)
+            {
+                targetW += 4;
+                targetBytes -= 8;
+            }
+        }
+    }
+    else if (rp->ReparseTag == IO_REPARSE_TAG_MOUNT_POINT)
+    {
+        if (rp->MountPointReparseBuffer.PrintNameLength > 0)
+        {
+            targetW = rp->MountPointReparseBuffer.PathBuffer +
+                (rp->MountPointReparseBuffer.PrintNameOffset / sizeof(wchar_t));
+            targetBytes = rp->MountPointReparseBuffer.PrintNameLength;
+        }
+        else
+        {
+            targetW = rp->MountPointReparseBuffer.PathBuffer +
+                (rp->MountPointReparseBuffer.SubstituteNameOffset / sizeof(wchar_t));
+            targetBytes = rp->MountPointReparseBuffer.SubstituteNameLength;
+
+            if (targetBytes >= 8 &&
+                wcsncmp(targetW, L"\\??\\", 4) == 0)
+            {
+                targetW += 4;
+                targetBytes -= 8;
+            }
+        }
+    }
+    else
+    {
+        errno = EINVAL;
+        return -1;
+    }
+
+    ULONG outBytes = 0;
+    if (!NT_SUCCESS(RtlUnicodeToUTF8N(buf, (ULONG) bufsiz, &outBytes, targetW, targetBytes)))
+    {
+        errno = E2BIG;
+        return -1;
+    }
+
+    // Not null-terminated
+    return (ssize_t) outBytes;
+}
+
+ssize_t readlink(const char* path, char* buf, size_t bufsiz)
+{
+    if (!path || !buf || bufsiz == 0)
+    {
+        errno = EINVAL;
+        return -1;
+    }
+
+    wchar_t pathW[MAX_PATH];
+    ULONG pathWBytes = 0;
+    if (!NT_SUCCESS(RtlUTF8ToUnicodeN(pathW, (ULONG) sizeof(pathW), &pathWBytes, path, (ULONG) strlen(path) + 1)))
+    {
+        errno = EINVAL;
+        return -1;
+    }
+
+    FF_AUTO_CLOSE_FD HANDLE hFile = CreateFileW(
+        pathW,
+        0,
+        FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE,
+        NULL,
+        OPEN_EXISTING,
+        FILE_FLAG_BACKUP_SEMANTICS | FILE_FLAG_OPEN_REPARSE_POINT,
+        NULL
+    );
+
+    if (hFile == INVALID_HANDLE_VALUE)
+    {
+        errno = winerr2Errno(GetLastError());
+        return -1;
+    }
+
+    return freadlink(hFile, buf, bufsiz);
+}
 #endif
diff --git a/src/common/path.h b/src/common/path.h
@@ -13,3 +13,10 @@ static inline bool ffIsAbsolutePath(const char* path)
     return path[0] == '/';
     #endif
 }
+
+#if _WIN32
+char* frealpath(void* __restrict hFile, char* __restrict resolved_name /*MAX_PATH*/);
+char* realpath(const char* __restrict file_name, char* __restrict resolved_name  /*MAX_PATH*/);
+ssize_t freadlink(void* hFile, char* buf, size_t bufsiz);
+ssize_t readlink(const char* path, char* buf, size_t bufsiz);
+#endif
diff --git a/src/detection/editor/editor.c b/src/detection/editor/editor.c
@@ -7,14 +7,6 @@
 
 #include <stdlib.h>
 
-#ifdef _WIN32
-static inline char* realpath(const char* restrict file_name, char* restrict resolved_name)
-{
-    assert(resolved_name != NULL);
-    return _fullpath(resolved_name, file_name, _MAX_PATH);
-}
-#endif
-
 static bool extractNvimVersionFromBinary(const char* str, FF_MAYBE_UNUSED uint32_t len, void* userdata)
 {
     if (!ffStrStartsWith(str, "NVIM v")) return true;
diff --git a/src/logo/image/image.c b/src/logo/image/image.c
@@ -407,17 +407,7 @@ static bool printImageKittyDirect(bool printError)
 #include <sys/ioctl.h>
 #else
 #include <wincon.h>
-
-static inline char* realpath(const char* restrict file_name, char* restrict resolved_name)
-{
-    char* result = _fullpath(resolved_name, file_name, _MAX_PATH);
-    if(result)
-    {
-        resolved_name[1] = resolved_name[0]; // Drive Name
-        resolved_name[0] = '/';
-    }
-    return result;
-}
+#include "common/path.h"
 #endif
 
 #ifdef FF_HAVE_ZLIB
@@ -1002,14 +992,21 @@ static bool printImageIfExistsSlowPath(FFLogoType type, bool printError)
     ffStrbufAppendS(&requestData.cacheDir, "fastfetch/images");
 
     ffStrbufEnsureFree(&requestData.cacheDir, PATH_MAX);
-    if(realpath(instance.config.logo.source.chars, requestData.cacheDir.chars + requestData.cacheDir.length) == NULL)
+    char* filePath = requestData.cacheDir.chars + requestData.cacheDir.length;
+    if(realpath(instance.config.logo.source.chars, filePath) == NULL)
     {
         //We can safely return here, because if realpath failed, we surely won't be able to read the file
         ffStrbufDestroy(&requestData.cacheDir);
         if(printError)
             fputs("Logo: Querying realpath of the image source failed\n", stderr);
         return false;
     }
+
+    #ifdef _WIN32
+    filePath[1] = filePath[0]; // Drive Name
+    filePath[0] = '/';
+    #endif
+
     ffStrbufRecalculateLength(&requestData.cacheDir);
     ffStrbufEnsureEndsWithC(&requestData.cacheDir, '/');
     ffStrbufAppendF(&requestData.cacheDir, "%u*%u/", requestData.logoPixelWidth, requestData.logoPixelHeight);

Original file line number	Diff line number	Diff line change
`@@ -28,7 +28,7 @@ static void getExePath(FFPlatform* platform)`
`28`	`28`	`NULL);`
`29`	`29`	`if (hPath != INVALID_HANDLE_VALUE)`
`30`	`30`	`{`
`31`		`- DWORD len = GetFinalPathNameByHandleW(hPath, exePathW, MAX_PATH, FILE_NAME_OPENED);`
	`31`	`+ DWORD len = GetFinalPathNameByHandleW(hPath, exePathW, MAX_PATH, FILE_NAME_NORMALIZED);`
`32`	`32`	`if (len > 0 && len < MAX_PATH)`
`33`	`33`	`{`
`34`	`34`	`ffStrbufSetNWS(&platform->exePath, len, exePathW);`