diff options
Diffstat (limited to 'sys/os/os_omar.c')
| -rw-r--r-- | sys/os/os_omar.c | 159 |
1 files changed, 159 insertions, 0 deletions
diff --git a/sys/os/os_omar.c b/sys/os/os_omar.c new file mode 100644 index 0000000..148f084 --- /dev/null +++ b/sys/os/os_omar.c @@ -0,0 +1,159 @@ +/* + * Copyright (c) 2025 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 <sys/types.h> +#include <sys/errno.h> +#include <sys/cdefs.h> +#include <os/omar.h> +#include <kern/panic.h> +#include <lib/limine.h> +#include <lib/string.h> + +#define OMAR_EOF "RAMO" +#define OMAR_REG 0 +#define OMAR_DIR 1 +#define BLOCK_SIZE 512 + +static const char *omar_root = NULL; +static struct limine_module_response *mod_resp; +static volatile struct limine_module_request mod_req = { + .id = LIMINE_MODULE_REQUEST, + .revision = 0 +}; + +/* + * The OMAR file header, describes the basics + * of a file. + * + * @magic: Header magic ("OMAR") + * @len: Length of the file + * @namelen: Length of the filename + * @rev: OMAR revision + * @mode: File permissions + */ +struct __packed omar_hdr { + char magic[4]; + uint8_t type; + uint8_t namelen; + uint32_t len; + uint8_t rev; + uint32_t mode; +}; + +static void * +omar_mod_query(const char *path) +{ + if (mod_resp == NULL || path == NULL) { + return NULL; + } + + for (size_t i = 0; i < mod_resp->module_count; ++i) { + if (strcmp(mod_resp->modules[i]->path, path) == 0) { + return mod_resp->modules[i]->address; + } + } + + return NULL; +} + +int +omar_lookup(const char *path, struct initrd_node *res) +{ + struct initrd_node node; + const struct omar_hdr *hdr; + const char *p, *name; + char namebuf[256]; + off_t off; + + if (*path++ != '/') { + return -ENOENT; + } + + p = omar_root; + for (;;) { + hdr = (struct omar_hdr *)p; + if (strncmp(hdr->magic, OMAR_EOF, sizeof(OMAR_EOF)) == 0) { + break; + } + + /* Ensure the file is valid */ + if (strncmp(hdr->magic, "OMAR", 4) != 0) { + /* Bad magic */ + return -EINVAL; + } + if (hdr->namelen > sizeof(namebuf) - 1) { + return -EINVAL; + } + + name = (char *)p + sizeof(struct omar_hdr); + memcpy(namebuf, name, hdr->namelen); + namebuf[hdr->namelen] = '\0'; + + /* Compute offset to next block */ + if (hdr->type == OMAR_DIR) { + off = 512; + } else { + off = ALIGN_UP(sizeof(*hdr) + hdr->namelen + hdr->len, BLOCK_SIZE); + } + + /* Skip header and name, right to the data */ + p = (char *)hdr + sizeof(struct omar_hdr); + p += hdr->namelen; + + if (strcmp(namebuf, path) == 0) { + node.mode = hdr->mode; + node.size = hdr->len; + node.data = (void *)p; + *res = node; + return 0; + } + + hdr = (struct omar_hdr *)((char *)hdr + off); + p = (char *)hdr; + memset(namebuf, 0, sizeof(namebuf)); + } + + return -ENOENT; +} + +void +omar_init(void) +{ + struct initrd_node node; + + mod_resp = mod_req.response; + if (mod_resp == NULL) { + panic("omar: could not get module response\n"); + } + + omar_root = omar_mod_query("/boot/initramfs.omar"); + if (omar_root == NULL) { + panic("omar: could not read /boot/initramfs.omar\n"); + } +} |