From 39a923f6c3c471f169552cf4e98b02c5173c2283 Mon Sep 17 00:00:00 2001 From: Ian Moffett Date: Wed, 28 Feb 2024 21:14:30 -0500 Subject: kernel: Add initial VFS implementation Signed-off-by: Ian Moffett --- sys/fs/initramfs.c | 125 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 125 insertions(+) create mode 100644 sys/fs/initramfs.c (limited to 'sys/fs/initramfs.c') diff --git a/sys/fs/initramfs.c b/sys/fs/initramfs.c new file mode 100644 index 0000000..7812b9c --- /dev/null +++ b/sys/fs/initramfs.c @@ -0,0 +1,125 @@ +/* + * Copyright (c) 2023-2024 Ian Marco Moffett and the Osmora Team. + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions are met: + * + * 1. Redistributions of source code must retain the above copyright notice, + * this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. Neither the name of Hyra nor the names of its + * contributors may be used to endorse or promote products derived from + * this software without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" + * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE + * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR + * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF + * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS + * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN + * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) + * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE + * POSSIBILITY OF SUCH DAMAGE. + */ + +#include +#include +#include +#include +#include +#include + +__MODULE_NAME("initramfs"); +__KERNEL_META("$Hyra$: initramfs.c, Ian Marco Moffett, " + "Initial ram filesystem"); + +static volatile struct limine_module_request mod_req = { + .id = LIMINE_MODULE_REQUEST, + .revision = 0 +}; + +static const char *initramfs = NULL; +static size_t initramfs_size = 0; + +struct tar_hdr { + char filename[100]; + char mode[8]; + char uid[8]; + char gid[8]; + char size[12]; + char mtime[12]; + char chksum[8]; + char typeflag[1]; +}; + +static char * +get_module(const char *path, uint64_t *size) { + for (uint64_t i = 0; i < mod_req.response->module_count; ++i) { + if (strcmp(mod_req.response->modules[i]->path, path) == 0) { + *size = mod_req.response->modules[i]->size; + return mod_req.response->modules[i]->address; + } + } + + return NULL; +} + +static size_t +getsize(const char *in) +{ + size_t size = 0, count = 1; + + for (size_t j = 11; j > 0; --j, count *= 8) { + size += (in[j-1]-'0')*count; + } + + return size; +} + +static int +initramfs_init(void) +{ + initramfs = get_module("/boot/initramfs.tar", &initramfs_size); + + if (initramfs == NULL) { + panic("Failed to load initramfs\n"); + } + + return 0; +} + +const char * +initramfs_open(const char *path) +{ + uintptr_t addr, size; + struct tar_hdr *hdr; + + if (initramfs == NULL) { + initramfs_init(); + } + + if (strlen(path) > 99) { + return NULL; + } + + addr = (uintptr_t)initramfs + 0x200; + hdr = (struct tar_hdr *)addr; + + while (hdr->filename[0] != '\0') { + hdr = (struct tar_hdr *)addr; + size = getsize(hdr->size); + + if (strcmp(hdr->filename, path) == 0) { + return ((char*)addr) + 0x200; + } + + addr += (((size + 511) / 512) + 1) * 512; + } + + return NULL; +} -- cgit v1.2.3