rename common to src

+ I keep starting to type src and wondering why autocomplete won't work,
  I guess src is just uncounciously a better name

1 files changed, 167 insertions, 0 deletions

diff --git a/src/initrd.c b/src/initrd.c
new file mode 100644
index 0000000..caff8b3
--- /dev/null
+++ b/src/initrd.c
@@ -0,0 +1,167 @@
+/* SPDX-License-Identifier: copyleft-next-0.3.1 */
+/* Copyright 2021 - 2022, Kim Kuparinen < kimi.h.kuparinen@gmail.com > */
+
+/**
+ * @file initrd.c
+ * Handle initrd, implement cpio with newc format.
+ */
+
+#include <kmi/initrd.h>
+#include <kmi/vmem.h>
+#include <kmi/string.h>
+#include <kmi/utils.h>
+#include <kmi/attrs.h>
+#include <kmi/debug.h>
+#include <libfdt.h>
+
+/** GNU cpio, POSIX 'newc' format header. */
+struct __packed cpio_header {
+	/** Magic bytes. */
+	char c_magic[6];
+
+	/** File inode. */
+	char c_ino[8];
+
+	/** File type and permissions. */
+	char c_mode[8];
+
+	/** User ID. */
+	char c_uid[8];
+
+	/** Group ID. */
+	char c_gid[8];
+
+	/** Number of links to this file. */
+	char c_nlink[8];
+
+	/** Modification time. */
+	char c_mtime[8];
+
+	/** Size of file. */
+	char c_filesize[8];
+
+	/** Device major. */
+	char c_devmajor[8];
+
+	/** Device minor. */
+	char c_devminor[8];
+
+	/** Block device major. */
+	char c_rdevmajor[8];
+
+	/** Block device minor. */
+	char c_rdevminor[8];
+
+	/** Length of filename. */
+	char c_namesize[8];
+
+	/** CRC check. */
+	char c_check[8];
+};
+
+/**
+ * Get next file in archive.
+ * Does not check for out of bounds.
+ *
+ * @param cp Pointer to current file header.
+ * @return Pointer to next file header.
+ */
+static struct cpio_header *__next_entry(struct cpio_header *cp)
+{
+	size_t blen = align_up(
+		sizeof(struct cpio_header) + convnum(cp->c_namesize, 8, 16), 4);
+	size_t tlen = align_up(convnum(cp->c_filesize, 8, 16), 4);
+
+	return (struct cpio_header *)(((char *)cp) + blen + tlen);
+}
+
+/**
+ * Get file with name in archive.
+ *
+ * @param c Pointer to initrd.
+ * @param fname Filename to look for.
+ * @param fname_len Length of filename.
+ * @return Pointer to corresponding file header if found, \c NULL otherwise.
+ */
+static struct cpio_header *__find_file(const char *c, const char *fname,
+                                       size_t fname_len)
+{
+	struct cpio_header *cp = (struct cpio_header *)c;
+	for (; cp; cp = __next_entry(cp)) {
+		size_t namelen = convnum(cp->c_namesize, 8, 16);
+		if (namelen == 0)
+			return NULL;
+
+		if (namelen < fname_len)
+			continue;
+
+		char *name = (char *)(cp + 1);
+		if (fname[0] != '/')
+			name += namelen - (fname_len + 1); /* match ending */
+
+		if (strncmp(name, fname, fname_len) == 0)
+			return cp;
+	}
+
+	return NULL;
+}
+
+/** Name of \c init program. */
+static char init_n[] = "init";
+
+/** Length of \c init name. */
+static size_t init_nlen = ARRAY_SIZE(init_n) - 1; /* ignore trailing NULL */
+
+pm_t get_initrdtop(const void *fdt)
+{
+	int chosen_offset = fdt_path_offset(fdt, "/chosen");
+	struct cell_info ci = get_cellinfo(fdt, chosen_offset);
+
+	void *initrd_end_ptr = (void *)fdt_getprop(fdt, chosen_offset,
+	                                           "linux,initrd-end", NULL);
+
+	/* fdt is only aware of physical memory pointers */
+	return (pm_t)__va(fdt_load_int_ptr(ci.addr_cells, initrd_end_ptr));
+}
+
+pm_t get_initrdbase(const void *fdt)
+{
+	const int chosen_offset = fdt_path_offset(fdt, "/chosen");
+	const struct cell_info ci = get_cellinfo(fdt, chosen_offset);
+
+	void *initrd_base_ptr = (void *)fdt_getprop(fdt, chosen_offset,
+	                                            "linux,initrd-start", NULL);
+
+	return (pm_t)__va(fdt_load_int_ptr(ci.addr_cells, initrd_base_ptr));
+}
+
+
+size_t get_init_size(const void *fdt)
+{
+	char *c = (char *)get_initrdbase(fdt);
+	struct cpio_header *cp = __find_file(c, init_n, init_nlen);
+	return convnum(cp->c_filesize, 8, 16);
+}
+
+vm_t get_init_base(const void *fdt)
+{
+	char *c = (char *)get_initrdbase(fdt);
+	struct cpio_header *cp = __find_file(c, init_n, init_nlen);
+	size_t name_len = convnum(cp->c_namesize, 8, 16);
+	return ((vm_t)cp) + align_up(sizeof(struct cpio_header) + name_len, 4);
+}
+
+stat_t move_init(const void *fdt, void *target)
+{
+	const char *c = (const char *)get_initrdbase(fdt);
+
+	const struct cpio_header *cp = __find_file(c, init_n, init_nlen);
+	size_t name_len = convnum(cp->c_namesize, 8, 16);
+	size_t file_len = convnum(cp->c_filesize, 8, 16);
+
+	char *fp = (char *)cp;
+	fp += align_up(sizeof(struct cpio_header) + name_len, 4);
+
+	memmove(target, fp, file_len);
+	return OK;
+}