vmcore.c

linux 内核源代码

			if (nhdr_ptr->n_namesz == 0)
				break;
			sz = sizeof(Elf32_Nhdr) +
				((nhdr_ptr->n_namesz + 3) & ~3) +
				((nhdr_ptr->n_descsz + 3) & ~3);
			real_sz += sz;
			nhdr_ptr = (Elf32_Nhdr*)((char*)nhdr_ptr + sz);
		}

		/* Add this contiguous chunk of notes section to vmcore list.*/
		new = get_new_element();
		if (!new) {
			kfree(notes_section);
			return -ENOMEM;
		}
		new->paddr = phdr_ptr->p_offset;
		new->size = real_sz;
		list_add_tail(&new->list, vc_list);
		phdr_sz += real_sz;
		kfree(notes_section);
	}

	/* Prepare merged PT_NOTE program header. */
	phdr.p_type    = PT_NOTE;
	phdr.p_flags   = 0;
	note_off = sizeof(Elf32_Ehdr) +
			(ehdr_ptr->e_phnum - nr_ptnote +1) * sizeof(Elf32_Phdr);
	phdr.p_offset  = note_off;
	phdr.p_vaddr   = phdr.p_paddr = 0;
	phdr.p_filesz  = phdr.p_memsz = phdr_sz;
	phdr.p_align   = 0;

	/* Add merged PT_NOTE program header*/
	tmp = elfptr + sizeof(Elf32_Ehdr);
	memcpy(tmp, &phdr, sizeof(phdr));
	tmp += sizeof(phdr);

	/* Remove unwanted PT_NOTE program headers. */
	i = (nr_ptnote - 1) * sizeof(Elf32_Phdr);
	*elfsz = *elfsz - i;
	memmove(tmp, tmp+i, ((*elfsz)-sizeof(Elf32_Ehdr)-sizeof(Elf32_Phdr)));

	/* Modify e_phnum to reflect merged headers. */
	ehdr_ptr->e_phnum = ehdr_ptr->e_phnum - nr_ptnote + 1;

	return 0;
}

/* Add memory chunks represented by program headers to vmcore list. Also update
 * the new offset fields of exported program headers. */
static int __init process_ptload_program_headers_elf64(char *elfptr,
						size_t elfsz,
						struct list_head *vc_list)
{
	int i;
	Elf64_Ehdr *ehdr_ptr;
	Elf64_Phdr *phdr_ptr;
	loff_t vmcore_off;
	struct vmcore *new;

	ehdr_ptr = (Elf64_Ehdr *)elfptr;
	phdr_ptr = (Elf64_Phdr*)(elfptr + sizeof(Elf64_Ehdr)); /* PT_NOTE hdr */

	/* First program header is PT_NOTE header. */
	vmcore_off = sizeof(Elf64_Ehdr) +
			(ehdr_ptr->e_phnum) * sizeof(Elf64_Phdr) +
			phdr_ptr->p_memsz; /* Note sections */

	for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
		if (phdr_ptr->p_type != PT_LOAD)
			continue;

		/* Add this contiguous chunk of memory to vmcore list.*/
		new = get_new_element();
		if (!new)
			return -ENOMEM;
		new->paddr = phdr_ptr->p_offset;
		new->size = phdr_ptr->p_memsz;
		list_add_tail(&new->list, vc_list);

		/* Update the program header offset. */
		phdr_ptr->p_offset = vmcore_off;
		vmcore_off = vmcore_off + phdr_ptr->p_memsz;
	}
	return 0;
}

static int __init process_ptload_program_headers_elf32(char *elfptr,
						size_t elfsz,
						struct list_head *vc_list)
{
	int i;
	Elf32_Ehdr *ehdr_ptr;
	Elf32_Phdr *phdr_ptr;
	loff_t vmcore_off;
	struct vmcore *new;

	ehdr_ptr = (Elf32_Ehdr *)elfptr;
	phdr_ptr = (Elf32_Phdr*)(elfptr + sizeof(Elf32_Ehdr)); /* PT_NOTE hdr */

	/* First program header is PT_NOTE header. */
	vmcore_off = sizeof(Elf32_Ehdr) +
			(ehdr_ptr->e_phnum) * sizeof(Elf32_Phdr) +
			phdr_ptr->p_memsz; /* Note sections */

	for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
		if (phdr_ptr->p_type != PT_LOAD)
			continue;

		/* Add this contiguous chunk of memory to vmcore list.*/
		new = get_new_element();
		if (!new)
			return -ENOMEM;
		new->paddr = phdr_ptr->p_offset;
		new->size = phdr_ptr->p_memsz;
		list_add_tail(&new->list, vc_list);

		/* Update the program header offset */
		phdr_ptr->p_offset = vmcore_off;
		vmcore_off = vmcore_off + phdr_ptr->p_memsz;
	}
	return 0;
}

/* Sets offset fields of vmcore elements. */
static void __init set_vmcore_list_offsets_elf64(char *elfptr,
						struct list_head *vc_list)
{
	loff_t vmcore_off;
	Elf64_Ehdr *ehdr_ptr;
	struct vmcore *m;

	ehdr_ptr = (Elf64_Ehdr *)elfptr;

	/* Skip Elf header and program headers. */
	vmcore_off = sizeof(Elf64_Ehdr) +
			(ehdr_ptr->e_phnum) * sizeof(Elf64_Phdr);

	list_for_each_entry(m, vc_list, list) {
		m->offset = vmcore_off;
		vmcore_off += m->size;
	}
}

/* Sets offset fields of vmcore elements. */
static void __init set_vmcore_list_offsets_elf32(char *elfptr,
						struct list_head *vc_list)
{
	loff_t vmcore_off;
	Elf32_Ehdr *ehdr_ptr;
	struct vmcore *m;

	ehdr_ptr = (Elf32_Ehdr *)elfptr;

	/* Skip Elf header and program headers. */
	vmcore_off = sizeof(Elf32_Ehdr) +
			(ehdr_ptr->e_phnum) * sizeof(Elf32_Phdr);

	list_for_each_entry(m, vc_list, list) {
		m->offset = vmcore_off;
		vmcore_off += m->size;
	}
}

static int __init parse_crash_elf64_headers(void)
{
	int rc=0;
	Elf64_Ehdr ehdr;
	u64 addr;

	addr = elfcorehdr_addr;

	/* Read Elf header */
	rc = read_from_oldmem((char*)&ehdr, sizeof(Elf64_Ehdr), &addr, 0);
	if (rc < 0)
		return rc;

	/* Do some basic Verification. */
	if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0 ||
		(ehdr.e_type != ET_CORE) ||
		!vmcore_elf_check_arch(&ehdr) ||
		ehdr.e_ident[EI_CLASS] != ELFCLASS64 ||
		ehdr.e_ident[EI_VERSION] != EV_CURRENT ||
		ehdr.e_version != EV_CURRENT ||
		ehdr.e_ehsize != sizeof(Elf64_Ehdr) ||
		ehdr.e_phentsize != sizeof(Elf64_Phdr) ||
		ehdr.e_phnum == 0) {
		printk(KERN_WARNING "Warning: Core image elf header is not"
					"sane\n");
		return -EINVAL;
	}

	/* Read in all elf headers. */
	elfcorebuf_sz = sizeof(Elf64_Ehdr) + ehdr.e_phnum * sizeof(Elf64_Phdr);
	elfcorebuf = kmalloc(elfcorebuf_sz, GFP_KERNEL);
	if (!elfcorebuf)
		return -ENOMEM;
	addr = elfcorehdr_addr;
	rc = read_from_oldmem(elfcorebuf, elfcorebuf_sz, &addr, 0);
	if (rc < 0) {
		kfree(elfcorebuf);
		return rc;
	}

	/* Merge all PT_NOTE headers into one. */
	rc = merge_note_headers_elf64(elfcorebuf, &elfcorebuf_sz, &vmcore_list);
	if (rc) {
		kfree(elfcorebuf);
		return rc;
	}
	rc = process_ptload_program_headers_elf64(elfcorebuf, elfcorebuf_sz,
							&vmcore_list);
	if (rc) {
		kfree(elfcorebuf);
		return rc;
	}
	set_vmcore_list_offsets_elf64(elfcorebuf, &vmcore_list);
	return 0;
}

static int __init parse_crash_elf32_headers(void)
{
	int rc=0;
	Elf32_Ehdr ehdr;
	u64 addr;

	addr = elfcorehdr_addr;

	/* Read Elf header */
	rc = read_from_oldmem((char*)&ehdr, sizeof(Elf32_Ehdr), &addr, 0);
	if (rc < 0)
		return rc;

	/* Do some basic Verification. */
	if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0 ||
		(ehdr.e_type != ET_CORE) ||
		!elf_check_arch(&ehdr) ||
		ehdr.e_ident[EI_CLASS] != ELFCLASS32||
		ehdr.e_ident[EI_VERSION] != EV_CURRENT ||
		ehdr.e_version != EV_CURRENT ||
		ehdr.e_ehsize != sizeof(Elf32_Ehdr) ||
		ehdr.e_phentsize != sizeof(Elf32_Phdr) ||
		ehdr.e_phnum == 0) {
		printk(KERN_WARNING "Warning: Core image elf header is not"
					"sane\n");
		return -EINVAL;
	}

	/* Read in all elf headers. */
	elfcorebuf_sz = sizeof(Elf32_Ehdr) + ehdr.e_phnum * sizeof(Elf32_Phdr);
	elfcorebuf = kmalloc(elfcorebuf_sz, GFP_KERNEL);
	if (!elfcorebuf)
		return -ENOMEM;
	addr = elfcorehdr_addr;
	rc = read_from_oldmem(elfcorebuf, elfcorebuf_sz, &addr, 0);
	if (rc < 0) {
		kfree(elfcorebuf);
		return rc;
	}

	/* Merge all PT_NOTE headers into one. */
	rc = merge_note_headers_elf32(elfcorebuf, &elfcorebuf_sz, &vmcore_list);
	if (rc) {
		kfree(elfcorebuf);
		return rc;
	}
	rc = process_ptload_program_headers_elf32(elfcorebuf, elfcorebuf_sz,
								&vmcore_list);
	if (rc) {
		kfree(elfcorebuf);
		return rc;
	}
	set_vmcore_list_offsets_elf32(elfcorebuf, &vmcore_list);
	return 0;
}

static int __init parse_crash_elf_headers(void)
{
	unsigned char e_ident[EI_NIDENT];
	u64 addr;
	int rc=0;

	addr = elfcorehdr_addr;
	rc = read_from_oldmem(e_ident, EI_NIDENT, &addr, 0);
	if (rc < 0)
		return rc;
	if (memcmp(e_ident, ELFMAG, SELFMAG) != 0) {
		printk(KERN_WARNING "Warning: Core image elf header"
					" not found\n");
		return -EINVAL;
	}

	if (e_ident[EI_CLASS] == ELFCLASS64) {
		rc = parse_crash_elf64_headers();
		if (rc)
			return rc;

		/* Determine vmcore size. */
		vmcore_size = get_vmcore_size_elf64(elfcorebuf);
	} else if (e_ident[EI_CLASS] == ELFCLASS32) {
		rc = parse_crash_elf32_headers();
		if (rc)
			return rc;

		/* Determine vmcore size. */
		vmcore_size = get_vmcore_size_elf32(elfcorebuf);
	} else {
		printk(KERN_WARNING "Warning: Core image elf header is not"
					" sane\n");
		return -EINVAL;
	}
	return 0;
}

/* Init function for vmcore module. */
static int __init vmcore_init(void)
{
	int rc = 0;

	/* If elfcorehdr= has been passed in cmdline, then capture the dump.*/
	if (!(elfcorehdr_addr < ELFCORE_ADDR_MAX))
		return rc;
	rc = parse_crash_elf_headers();
	if (rc) {
		printk(KERN_WARNING "Kdump: vmcore not initialized\n");
		return rc;
	}

	/* Initialize /proc/vmcore size if proc is already up. */
	if (proc_vmcore)
		proc_vmcore->size = vmcore_size;
	return 0;
}
module_init(vmcore_init)