From 7a9c3012282ede0489ac5583b0f97c720d7e7c6d Mon Sep 17 00:00:00 2001
From: Marvin Friedrich <contact@marvinf.com>
Date: Sun, 13 Apr 2025 03:42:16 +0200
Subject: [PATCH 1/4] config: Read config files from limine.d

---
 common/fs/file.h    | 13 ++++++++++
 common/fs/file.s2.c |  8 ++++++
 common/lib/config.c | 59 +++++++++++++++++++++++++++++++++++++++++++--
 3 files changed, 78 insertions(+), 2 deletions(-)

diff --git a/common/fs/file.h b/common/fs/file.h
index 86474bd0..ead8dfc3 100644
--- a/common/fs/file.h
+++ b/common/fs/file.h
@@ -14,6 +14,17 @@ extern bool case_insensitive_fopen;
 bool fs_get_guid(struct guid *guid, struct volume *part);
 char *fs_get_label(struct volume *part);
 
+enum {
+    DIR_ENTRY_TYPE_FILE,
+    DIR_ENTRY_TYPE_DIRECTORY,
+};
+
+#define DIR_ENTRY_NAME_LEN 384
+struct dir_entry {
+    char name[DIR_ENTRY_NAME_LEN];
+    int type;
+};
+
 struct file_handle {
     bool       is_memfile;
     bool       readall;
@@ -23,6 +34,7 @@ struct file_handle {
     void      *fd;
     void     (*read)(void *fd, void *buf, uint64_t loc, uint64_t count);
     void     (*close)(void *fd);
+    void    *(*readdir)(void *fd, size_t *out_size);
     uint64_t   size;
 #if defined (UEFI)
     EFI_HANDLE efi_part_handle;
@@ -35,6 +47,7 @@ struct file_handle {
 struct file_handle *fopen(struct volume *part, const char *filename);
 void fread(struct file_handle *fd, void *buf, uint64_t loc, uint64_t count);
 void fclose(struct file_handle *fd);
+struct dir_entry *freaddir(struct file_handle *fd, size_t *out_size);
 void *freadall(struct file_handle *fd, uint32_t type);
 void *freadall_mode(struct file_handle *fd, uint32_t type, bool allow_high_allocs
 #if defined (__i386__)
diff --git a/common/fs/file.s2.c b/common/fs/file.s2.c
index 8528f19a..7efa5e75 100644
--- a/common/fs/file.s2.c
+++ b/common/fs/file.s2.c
@@ -86,6 +86,14 @@ void fread(struct file_handle *fd, void *buf, uint64_t loc, uint64_t count) {
     }
 }
 
+struct dir_entry *freaddir(struct file_handle *fd, size_t *out_size) {
+    if (!fd || !fd->readdir) {
+        return NULL;
+    }
+
+    return fd->readdir(fd, out_size);
+}
+
 void *freadall(struct file_handle *fd, uint32_t type) {
     return freadall_mode(fd, type, false
 #if defined (__i386__)
diff --git a/common/lib/config.c b/common/lib/config.c
index a82aa08f..da5b4d2b 100644
--- a/common/lib/config.c
+++ b/common/lib/config.c
@@ -28,7 +28,11 @@ no_unwind bool bad_config = false;
 static char *config_addr;
 
 int init_config_disk(struct volume *part) {
-    struct file_handle *f;
+    struct file_handle *f;      // The config file
+    struct file_handle *dir;    // The limine.d directory
+    struct file_handle **files; // Files inside the limine.d directory
+    size_t num_files = 0;       // Amount of files inside limine.d
+    size_t config_size = 0;
 
     bool old_cif = case_insensitive_fopen;
     case_insensitive_fopen = true;
@@ -49,11 +53,62 @@ int init_config_disk(struct volume *part) {
 
 opened:
     case_insensitive_fopen = old_cif;
+    config_size = f->size + 2;
+
+    // Get the path of the loaded config file so we can get limine.d/ from the same directory.
+    char* loaded_dir = ext_mem_alloc(f->path_len);
+    memcpy(loaded_dir, f->path, f->path_len);
+    for (int i = f->path_len; i >= 0; i--) {
+        if (loaded_dir[i] == '/') {
+            memcpy(loaded_dir + i, "/limine.d/", 11);
+            break;
+        }
+    }
+
+    // Open the directory and get the amount of memory we need to allocate.
+    if ((dir = fopen(part, loaded_dir)) != NULL) {
+        size_t num_entries;
+        struct dir_entry *dir_entries = freaddir(dir, &num_entries);
+        files = ext_mem_alloc(num_entries * sizeof(struct file_handle *));
+        for (size_t i = 0; i < num_entries; i++) {
+            if (dir_entries[i].type == DIR_ENTRY_TYPE_FILE) {
+                // Build an absolute path.
+                char *file_path = ext_mem_alloc(strlen(loaded_dir) + strlen(dir_entries[i].name));
+                memcpy(file_path, loaded_dir, strlen(loaded_dir));
+                memcpy(file_path + strlen(loaded_dir), dir_entries[i].name, strlen(dir_entries[i].name));
+
+                struct file_handle *entry = fopen(part, file_path);
+                if (entry) {
+                    config_size += entry->size;
+                    files[num_files++] = entry;
+                }
+            }
+        }
+    }
 
-    size_t config_size = f->size + 2;
     config_addr = ext_mem_alloc(config_size);
 
+    // Read the main config file.
     fread(f, config_addr, 0, f->size);
+    size_t config_cursor = f->size;
+
+    // Sort all files by name in ascending order.
+    struct file_handle* temp = NULL;
+    for (size_t i = 1; i < num_files; i++) {
+        for (size_t j = 0; j < num_files - i; j++) {
+            if (strcmp(files[j]->path, files[j + 1]->path) > 0) {
+                temp = files[j];
+                files[j] = files[j + 1];
+                files[j + 1] = temp;
+            }
+        }
+    }
+
+    // Concatenate all limine.d files.
+    for (size_t i = 0; i < num_files; i++) {
+        fread(files[i], config_addr + config_cursor, 0, files[i]->size);
+        config_cursor += files[i]->size;
+    }
 
     fclose(f);
 

From 4a5e54dcad67ca62b1d09b2284d9ca74e92ca2a7 Mon Sep 17 00:00:00 2001
From: Marvin Friedrich <contact@marvinf.com>
Date: Sun, 13 Apr 2025 03:42:50 +0200
Subject: [PATCH 2/4] fs/fat: Implement readdir

---
 common/fs/fat32.s2.c | 136 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 136 insertions(+)

diff --git a/common/fs/fat32.s2.c b/common/fs/fat32.s2.c
index c01904b4..f86e3ba3 100644
--- a/common/fs/fat32.s2.c
+++ b/common/fs/fat32.s2.c
@@ -85,6 +85,11 @@ struct fat32_directory_entry {
     uint32_t file_size_bytes;
 } __attribute__((packed));
 
+struct fat32_directory_handle {
+    struct fat32_context context;
+    struct fat32_directory_entry entry;
+};
+
 struct fat32_lfn_entry {
     uint8_t sequence_number;
     char name1[10];
@@ -453,6 +458,7 @@ char *fat32_get_label(struct volume *part) {
 
 static void fat32_read(struct file_handle *handle, void *buf, uint64_t loc, uint64_t count);
 static void fat32_close(struct file_handle *file);
+static struct dir_entry *fat32_readdir(struct file_handle *file, size_t *out_size);
 
 struct file_handle *fat32_open(struct volume *part, const char *path) {
     struct fat32_context context;
@@ -515,6 +521,22 @@ struct file_handle *fat32_open(struct volume *part, const char *path) {
         if (expect_directory) {
             _current_directory = current_file;
             current_directory = &_current_directory;
+
+            if (path[current_index] == 0) {
+                struct file_handle *handle = ext_mem_alloc(sizeof(struct file_handle));
+                struct fat32_directory_handle *ret = ext_mem_alloc(sizeof(struct fat32_directory_handle));
+
+                ret->context = context;
+                ret->entry = _current_directory;
+
+                handle->fd = (void *)ret;
+                handle->readdir = (void *)fat32_readdir;
+                handle->vol = part;
+#if defined (UEFI)
+                handle->efi_part_handle = part->efi_part_handle;
+#endif
+                return handle;
+            }
         } else {
             struct file_handle *handle = ext_mem_alloc(sizeof(struct file_handle));
             struct fat32_file_handle *ret = ext_mem_alloc(sizeof(struct fat32_file_handle));
@@ -551,3 +573,117 @@ static void fat32_close(struct file_handle *file) {
     pmm_free(f->cluster_chain, f->chain_len * sizeof(uint32_t));
     pmm_free(f, sizeof(struct fat32_file_handle));
 }
+
+static struct dir_entry *fat32_readdir(struct file_handle *file, size_t *out_size) {
+    if (!file)
+        return NULL;
+
+    struct fat32_directory_handle *d = file->fd;
+    uint32_t current_cluster_number = d->entry.cluster_num_low;
+    if (d->context.type == 32)
+        current_cluster_number |= (uint32_t)d->entry.cluster_num_high << 16;
+
+    size_t dir_chain_len = 0;
+    uint32_t *directory_cluster_chain = cache_cluster_chain(&d->context, current_cluster_number, &dir_chain_len);
+
+    if (directory_cluster_chain == NULL)
+        return NULL;
+
+    struct fat32_directory_entry *directory_entries;
+    size_t block_size = d->context.sectors_per_cluster * d->context.bytes_per_sector;
+    directory_entries = ext_mem_alloc(dir_chain_len * block_size);
+    read_cluster_chain(&d->context, directory_cluster_chain, directory_entries, 0, dir_chain_len * block_size);
+    char current_lfn[FAT32_LFN_MAX_FILENAME_LENGTH] = {0};
+
+    const size_t num_entries = (dir_chain_len * block_size) / sizeof(struct fat32_directory_entry);
+    struct dir_entry *buffer = ext_mem_alloc(num_entries * sizeof(struct dir_entry));
+    size_t buffer_idx = 0;
+
+    for (size_t i = 0; i < num_entries; i++) {
+        if (directory_entries[i].file_name_and_ext[0] == 0x00) {
+            // no more entries here
+            break;
+        }
+
+        if (directory_entries[i].attribute == FAT32_LFN_ATTRIBUTE) {
+            struct fat32_lfn_entry* lfn = (struct fat32_lfn_entry*) &directory_entries[i];
+
+            if (lfn->sequence_number & 0b01000000) {
+                // this lfn is the first entry in the table, clear the lfn buffer
+                memset(current_lfn, ' ', sizeof(current_lfn));
+            }
+
+            const unsigned int lfn_index = ((lfn->sequence_number & 0b00011111) - 1U) * 13U;
+            if (lfn_index >= FAT32_LFN_MAX_ENTRIES * 13) {
+                continue;
+            }
+
+            fat32_lfncpy(current_lfn + lfn_index + 00, lfn->name1, 5);
+            fat32_lfncpy(current_lfn + lfn_index + 05, lfn->name2, 6);
+            fat32_lfncpy(current_lfn + lfn_index + 11, lfn->name3, 2);
+
+            if (lfn_index != 0)
+                continue;
+
+            // Remove trailing spaces.
+            for (int j = SIZEOF_ARRAY(current_lfn) - 2; j >= -1; j--) {
+                if (j == -1 || current_lfn[j] != ' ') {
+                    current_lfn[j + 1] = 0;
+                    break;
+                }
+            }
+
+            continue;
+        }
+
+        if (directory_entries[i].attribute & (1 << 3)) {
+            // It is a volume label, skip
+            continue;
+        }
+
+        if (i > 0 && directory_entries[i - 1].attribute == FAT32_LFN_ATTRIBUTE) {
+            memcpy(buffer[buffer_idx].name, current_lfn, sizeof(current_lfn));
+        } else {
+            // SFN
+            char sfn[8 + 1 + 3 + 1]; // 8 + '.' + 3 + NUL
+            size_t sfn_idx = 8;
+            memcpy(sfn, directory_entries[i].file_name_and_ext, 8);
+            // Remove trailing spaces.
+            for (int j = 7; j >= 0; j--) {
+                if (sfn[j] == ' ') {
+                    sfn[j] = 0;
+                    sfn_idx = j;
+                    continue;
+                }
+                break;
+            }
+            // Check if we have a filename extension.
+            if (directory_entries[i].file_name_and_ext[8] != ' ') {
+                sfn[sfn_idx++] = '.';
+                memcpy(sfn + sfn_idx, directory_entries[i].file_name_and_ext + 8, 3);
+                for (int j = 2; j >= 0; j--) {
+                    if (sfn[sfn_idx + j] == ' ') {
+                        sfn[sfn_idx + j] = 0;
+                        continue;
+                    }
+                    break;
+                }
+            }
+            memcpy(buffer[buffer_idx].name, sfn, sizeof(sfn));
+        }
+
+        if (directory_entries[i].attribute == FAT32_ATTRIBUTE_SUBDIRECTORY) {
+            buffer[buffer_idx].type = DIR_ENTRY_TYPE_DIRECTORY;
+        } else {
+            buffer[buffer_idx].type = DIR_ENTRY_TYPE_FILE;
+        }
+
+        buffer_idx++;
+    }
+
+    pmm_free(directory_cluster_chain, dir_chain_len * sizeof(uint32_t));
+
+    *out_size = buffer_idx;
+
+    return buffer;
+}

From d07ff227cb6d58e3b0b69452deadf7ab7b8db6da Mon Sep 17 00:00:00 2001
From: Marvin Friedrich <contact@marvinf.com>
Date: Sun, 13 Apr 2025 03:43:10 +0200
Subject: [PATCH 3/4] test: Use split config files

---
 .gitignore                           |  3 +++
 test/limine.conf                     | 35 ----------------------------
 test/limine.d/00-multiboot.conf      |  9 +++++++
 test/limine.d/01-efi-chainload.conf  |  5 ++++
 test/limine.d/02-bios-chainload.conf |  5 ++++
 test/limine.d/03-legacy.conf         | 12 ++++++++++
 6 files changed, 34 insertions(+), 35 deletions(-)
 create mode 100644 test/limine.d/00-multiboot.conf
 create mode 100644 test/limine.d/01-efi-chainload.conf
 create mode 100644 test/limine.d/02-bios-chainload.conf
 create mode 100644 test/limine.d/03-legacy.conf

diff --git a/.gitignore b/.gitignore
index e9e4cbd4..018dc037 100644
--- a/.gitignore
+++ b/.gitignore
@@ -22,6 +22,9 @@
 *.dtb
 *~
 
+# Keep limine.d, since the .d conflicts with the '*.d' rule
+!test/limine.d
+
 /bin
 /build
 /toolchain-files
diff --git a/test/limine.conf b/test/limine.conf
index c2bc08fc..945438c2 100644
--- a/test/limine.conf
+++ b/test/limine.conf
@@ -22,38 +22,3 @@ backdrop: 008080
 
     module_path: boot():/boot/bg.jpg
     dtb_path: boot():/boot/device_tree.dtb
-
-/Multiboot2 Test
-    comment: Test of the multiboot2 boot protocol.
-
-    protocol: multiboot2
-    kernel_path: boot():/boot/multiboot2.elf
-    kernel_cmdline: This is an example kernel command line.
-
-    module_path: boot():/boot/bg.jpg
-    module_string: This is the first module.
-
-/EFI Chainloading
-    comment: Test EFI image chainloading.
-
-    protocol: efi_chainload
-    image_path: boot():/EFI/BOOT/BOOTX64.EFI
-
-/BIOS Chainloading
-    comment: Test BIOS chainloading.
-
-    protocol: bios_chainload
-    drive: 1
-
-/+Legacy
-    comment: Directory containing legacy entries.
-
-    //Multiboot1 Test
-        comment: Test of the multiboot1 boot protocol.
-
-        protocol: multiboot1
-        kernel_path: boot():/boot/multiboot.elf
-        kernel_cmdline: This is an example kernel command line.
-
-        module_path: boot():/boot/bg.jpg
-        module_string: This is the first module.
diff --git a/test/limine.d/00-multiboot.conf b/test/limine.d/00-multiboot.conf
new file mode 100644
index 00000000..747c34c4
--- /dev/null
+++ b/test/limine.d/00-multiboot.conf
@@ -0,0 +1,9 @@
+/Multiboot2 Test
+    comment: Test of the multiboot2 boot protocol.
+
+    protocol: multiboot2
+    kernel_path: boot():/boot/multiboot2.elf
+    kernel_cmdline: This is an example kernel command line.
+
+    module_path: boot():/boot/bg.jpg
+    module_string: This is the first module.
diff --git a/test/limine.d/01-efi-chainload.conf b/test/limine.d/01-efi-chainload.conf
new file mode 100644
index 00000000..5b277377
--- /dev/null
+++ b/test/limine.d/01-efi-chainload.conf
@@ -0,0 +1,5 @@
+/EFI Chainloading
+    comment: Test EFI image chainloading.
+
+    protocol: efi_chainload
+    image_path: boot():/EFI/BOOT/BOOTX64.EFI
diff --git a/test/limine.d/02-bios-chainload.conf b/test/limine.d/02-bios-chainload.conf
new file mode 100644
index 00000000..725f30bf
--- /dev/null
+++ b/test/limine.d/02-bios-chainload.conf
@@ -0,0 +1,5 @@
+/BIOS Chainloading
+    comment: Test BIOS chainloading.
+
+    protocol: bios_chainload
+    drive: 1
diff --git a/test/limine.d/03-legacy.conf b/test/limine.d/03-legacy.conf
new file mode 100644
index 00000000..33c12f7d
--- /dev/null
+++ b/test/limine.d/03-legacy.conf
@@ -0,0 +1,12 @@
+/+Legacy
+    comment: Directory containing legacy entries.
+
+    //Multiboot1 Test
+        comment: Test of the multiboot1 boot protocol.
+
+        protocol: multiboot1
+        kernel_path: boot():/boot/multiboot.elf
+        kernel_cmdline: This is an example kernel command line.
+
+        module_path: boot():/boot/bg.jpg
+        module_string: This is the first module.

From 951c7c58cb28bf8f1f32deb314f8740df8d8d654 Mon Sep 17 00:00:00 2001
From: Marvin Friedrich <contact@marvinf.com>
Date: Sun, 13 Apr 2025 03:43:54 +0200
Subject: [PATCH 4/4] docs: Document split config file loading

---
 CONFIG.md | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/CONFIG.md b/CONFIG.md
index aec29781..ae8ce2a0 100644
--- a/CONFIG.md
+++ b/CONFIG.md
@@ -25,6 +25,13 @@ candidates in subsequent partitions or directories are ignored.
 It is thus imperative that the intended config file is placed in a location
 that will not be shadowed by another candidate config file.
 
+## Split config files
+
+Limine allows loading multiple additional config file snippets from a directory
+named `limine.d/`. All files in that directory will be appended to
+`limine.conf`, sorted by their file name in ascending order.
+`limine.d/` has to be located in the same directory as `limine.conf`.
+
 ## Structure of the config file
 
 The Limine configuration file is comprised of *menu entries* and *options*.