[net-next-2.6.git] / fs / proc / kcore.c

/*
 *	fs/proc/kcore.c kernel ELF core dumper
 *
 *	Modelled on fs/exec.c:aout_core_dump()
 *	Jeremy Fitzhardinge <jeremy@sw.oz.au>
 *	ELF version written by David Howells <David.Howells@nexor.co.uk>
 *	Modified and incorporated into 2.3.x by Tigran Aivazian <tigran@veritas.com>
 *	Support to dump vmalloc'd areas (ELF only), Tigran Aivazian <tigran@veritas.com>
 *	Safe accesses to vmalloc/direct-mapped discontiguous areas, Kanoj Sarcar <kanoj@sgi.com>
 */

#include <linux/mm.h>
#include <linux/proc_fs.h>
#include <linux/user.h>
#include <linux/capability.h>
#include <linux/elf.h>
#include <linux/elfcore.h>
#include <linux/vmalloc.h>
#include <linux/highmem.h>
#include <linux/init.h>
#include <asm/uaccess.h>
#include <asm/io.h>

#define CORE_STR "CORE"

#ifndef ELF_CORE_EFLAGS
#define ELF_CORE_EFLAGS	0
#endif

static struct proc_dir_entry *proc_root_kcore;

static int open_kcore(struct inode * inode, struct file * filp)
{
	return capable(CAP_SYS_RAWIO) ? 0 : -EPERM;
}

static ssize_t read_kcore(struct file *, char __user *, size_t, loff_t *);

static const struct file_operations proc_kcore_operations = {
	.read		= read_kcore,
	.open		= open_kcore,
};

#ifndef kc_vaddr_to_offset
#define	kc_vaddr_to_offset(v) ((v) - PAGE_OFFSET)
#endif
#ifndef	kc_offset_to_vaddr
#define	kc_offset_to_vaddr(o) ((o) + PAGE_OFFSET)
#endif

/* An ELF note in memory */
struct memelfnote
{
	const char *name;
	int type;
	unsigned int datasz;
	void *data;
};

static struct kcore_list *kclist;
static DEFINE_RWLOCK(kclist_lock);

void
kclist_add(struct kcore_list *new, void *addr, size_t size)
{
	new->addr = (unsigned long)addr;
	new->size = size;

	write_lock(&kclist_lock);
	new->next = kclist;
	kclist = new;
	write_unlock(&kclist_lock);
}

static size_t get_kcore_size(int *nphdr, size_t *elf_buflen)
{
	size_t try, size;
	struct kcore_list *m;

	*nphdr = 1; /* PT_NOTE */
	size = 0;

	for (m=kclist; m; m=m->next) {
		try = kc_vaddr_to_offset((size_t)m->addr + m->size);
		if (try > size)
			size = try;
		*nphdr = *nphdr + 1;
	}
	*elf_buflen =	sizeof(struct elfhdr) + 
			(*nphdr + 2)*sizeof(struct elf_phdr) + 
			3 * ((sizeof(struct elf_note)) +
			     roundup(sizeof(CORE_STR), 4)) +
			roundup(sizeof(struct elf_prstatus), 4) +
			roundup(sizeof(struct elf_prpsinfo), 4) +
			roundup(sizeof(struct task_struct), 4);
	*elf_buflen = PAGE_ALIGN(*elf_buflen);
	return size + *elf_buflen;
}


/*****************************************************************************/
/*
 * determine size of ELF note
 */
static int notesize(struct memelfnote *en)
{
	int sz;

	sz = sizeof(struct elf_note);
	sz += roundup((strlen(en->name) + 1), 4);
	sz += roundup(en->datasz, 4);

	return sz;
} /* end notesize() */

/*****************************************************************************/
/*
 * store a note in the header buffer
 */
static char *storenote(struct memelfnote *men, char *bufp)
{
	struct elf_note en;

#define DUMP_WRITE(addr,nr) do { memcpy(bufp,addr,nr); bufp += nr; } while(0)

	en.n_namesz = strlen(men->name) + 1;
	en.n_descsz = men->datasz;
	en.n_type = men->type;

	DUMP_WRITE(&en, sizeof(en));
	DUMP_WRITE(men->name, en.n_namesz);

	/* XXX - cast from long long to long to avoid need for libgcc.a */
	bufp = (char*) roundup((unsigned long)bufp,4);
	DUMP_WRITE(men->data, men->datasz);
	bufp = (char*) roundup((unsigned long)bufp,4);

#undef DUMP_WRITE

	return bufp;
} /* end storenote() */

/*
 * store an ELF coredump header in the supplied buffer
 * nphdr is the number of elf_phdr to insert
 */
static void elf_kcore_store_hdr(char *bufp, int nphdr, int dataoff)
{
	struct elf_prstatus prstatus;	/* NT_PRSTATUS */
	struct elf_prpsinfo prpsinfo;	/* NT_PRPSINFO */
	struct elf_phdr *nhdr, *phdr;
	struct elfhdr *elf;
	struct memelfnote notes[3];
	off_t offset = 0;
	struct kcore_list *m;

	/* setup ELF header */
	elf = (struct elfhdr *) bufp;
	bufp += sizeof(struct elfhdr);
	offset += sizeof(struct elfhdr);
	memcpy(elf->e_ident, ELFMAG, SELFMAG);
	elf->e_ident[EI_CLASS]	= ELF_CLASS;
	elf->e_ident[EI_DATA]	= ELF_DATA;
	elf->e_ident[EI_VERSION]= EV_CURRENT;
	elf->e_ident[EI_OSABI] = ELF_OSABI;
	memset(elf->e_ident+EI_PAD, 0, EI_NIDENT-EI_PAD);
	elf->e_type	= ET_CORE;
	elf->e_machine	= ELF_ARCH;
	elf->e_version	= EV_CURRENT;
	elf->e_entry	= 0;
	elf->e_phoff	= sizeof(struct elfhdr);
	elf->e_shoff	= 0;
	elf->e_flags	= ELF_CORE_EFLAGS;
	elf->e_ehsize	= sizeof(struct elfhdr);
	elf->e_phentsize= sizeof(struct elf_phdr);
	elf->e_phnum	= nphdr;
	elf->e_shentsize= 0;
	elf->e_shnum	= 0;
	elf->e_shstrndx	= 0;

	/* setup ELF PT_NOTE program header */
	nhdr = (struct elf_phdr *) bufp;
	bufp += sizeof(struct elf_phdr);
	offset += sizeof(struct elf_phdr);
	nhdr->p_type	= PT_NOTE;
	nhdr->p_offset	= 0;
	nhdr->p_vaddr	= 0;
	nhdr->p_paddr	= 0;
	nhdr->p_filesz	= 0;
	nhdr->p_memsz	= 0;
	nhdr->p_flags	= 0;
	nhdr->p_align	= 0;

	/* setup ELF PT_LOAD program header for every area */
	for (m=kclist; m; m=m->next) {
		phdr = (struct elf_phdr *) bufp;
		bufp += sizeof(struct elf_phdr);
		offset += sizeof(struct elf_phdr);

		phdr->p_type	= PT_LOAD;
		phdr->p_flags	= PF_R|PF_W|PF_X;
		phdr->p_offset	= kc_vaddr_to_offset(m->addr) + dataoff;
		phdr->p_vaddr	= (size_t)m->addr;
		phdr->p_paddr	= 0;
		phdr->p_filesz	= phdr->p_memsz	= m->size;
		phdr->p_align	= PAGE_SIZE;
	}

	/*
	 * Set up the notes in similar form to SVR4 core dumps made
	 * with info from their /proc.
	 */
	nhdr->p_offset	= offset;

	/* set up the process status */
	notes[0].name = CORE_STR;
	notes[0].type = NT_PRSTATUS;
	notes[0].datasz = sizeof(struct elf_prstatus);
	notes[0].data = &prstatus;

	memset(&prstatus, 0, sizeof(struct elf_prstatus));

	nhdr->p_filesz	= notesize(&notes[0]);
	bufp = storenote(&notes[0], bufp);

	/* set up the process info */
	notes[1].name	= CORE_STR;
	notes[1].type	= NT_PRPSINFO;
	notes[1].datasz	= sizeof(struct elf_prpsinfo);
	notes[1].data	= &prpsinfo;

	memset(&prpsinfo, 0, sizeof(struct elf_prpsinfo));
	prpsinfo.pr_state	= 0;
	prpsinfo.pr_sname	= 'R';
	prpsinfo.pr_zomb	= 0;

	strcpy(prpsinfo.pr_fname, "vmlinux");
	strncpy(prpsinfo.pr_psargs, saved_command_line, ELF_PRARGSZ);

	nhdr->p_filesz	+= notesize(&notes[1]);
	bufp = storenote(&notes[1], bufp);

	/* set up the task structure */
	notes[2].name	= CORE_STR;
	notes[2].type	= NT_TASKSTRUCT;
	notes[2].datasz	= sizeof(struct task_struct);
	notes[2].data	= current;

	nhdr->p_filesz	+= notesize(&notes[2]);
	bufp = storenote(&notes[2], bufp);

} /* end elf_kcore_store_hdr() */

/*****************************************************************************/
/*
 * read from the ELF header and then kernel memory
 */
static ssize_t
read_kcore(struct file *file, char __user *buffer, size_t buflen, loff_t *fpos)
{
	ssize_t acc = 0;
	size_t size, tsz;
	size_t elf_buflen;
	int nphdr;
	unsigned long start;

	read_lock(&kclist_lock);
	proc_root_kcore->size = size = get_kcore_size(&nphdr, &elf_buflen);
	if (buflen == 0 || *fpos >= size) {
		read_unlock(&kclist_lock);
		return 0;
	}

	/* trim buflen to not go beyond EOF */
	if (buflen > size - *fpos)
		buflen = size - *fpos;

	/* construct an ELF core header if we'll need some of it */
	if (*fpos < elf_buflen) {
		char * elf_buf;

		tsz = elf_buflen - *fpos;
		if (buflen < tsz)
			tsz = buflen;
		elf_buf = kzalloc(elf_buflen, GFP_ATOMIC);
		if (!elf_buf) {
			read_unlock(&kclist_lock);
			return -ENOMEM;
		}
		elf_kcore_store_hdr(elf_buf, nphdr, elf_buflen);
		read_unlock(&kclist_lock);
		if (copy_to_user(buffer, elf_buf + *fpos, tsz)) {
			kfree(elf_buf);
			return -EFAULT;
		}
		kfree(elf_buf);
		buflen -= tsz;
		*fpos += tsz;
		buffer += tsz;
		acc += tsz;

		/* leave now if filled buffer already */
		if (buflen == 0)
			return acc;
	} else
		read_unlock(&kclist_lock);

	/*
	 * Check to see if our file offset matches with any of
	 * the addresses in the elf_phdr on our list.
	 */
	start = kc_offset_to_vaddr(*fpos - elf_buflen);
	if ((tsz = (PAGE_SIZE - (start & ~PAGE_MASK))) > buflen)
		tsz = buflen;
		
	while (buflen) {
		struct kcore_list *m;

		read_lock(&kclist_lock);
		for (m=kclist; m; m=m->next) {
			if (start >= m->addr && start < (m->addr+m->size))
				break;
		}
		read_unlock(&kclist_lock);

		if (m == NULL) {
			if (clear_user(buffer, tsz))
				return -EFAULT;
		} else if (is_vmalloc_addr((void *)start)) {
			char * elf_buf;

			elf_buf = kzalloc(tsz, GFP_KERNEL);
			if (!elf_buf)
				return -ENOMEM;
			vread(elf_buf, (char *)start, tsz);
			/* we have to zero-fill user buffer even if no read */
			if (copy_to_user(buffer, elf_buf, tsz)) {
				kfree(elf_buf);
				return -EFAULT;
			}
			kfree(elf_buf);
		} else {
			if (kern_addr_valid(start)) {
				unsigned long n;

				n = copy_to_user(buffer, (char *)start, tsz);
				/*
				 * We cannot distingush between fault on source
				 * and fault on destination. When this happens
				 * we clear too and hope it will trigger the
				 * EFAULT again.
				 */
				if (n) { 
					if (clear_user(buffer + tsz - n,
								n))
						return -EFAULT;
				}
			} else {
				if (clear_user(buffer, tsz))
					return -EFAULT;
			}
		}
		buflen -= tsz;
		*fpos += tsz;
		buffer += tsz;
		acc += tsz;
		start += tsz;
		tsz = (buflen > PAGE_SIZE ? PAGE_SIZE : buflen);
	}

	return acc;
}

static int __init proc_kcore_init(void)
{
	proc_root_kcore = proc_create("kcore", S_IRUSR, NULL, &proc_kcore_operations);
	if (proc_root_kcore)
		proc_root_kcore->size =
				(size_t)high_memory - PAGE_OFFSET + PAGE_SIZE;
	return 0;
}
module_init(proc_kcore_init);
Commit	Line	Data
1da177e4 LT	1	/*
	2	* fs/proc/kcore.c kernel ELF core dumper
	3	*
	4	* Modelled on fs/exec.c:aout_core_dump()
	5	* Jeremy Fitzhardinge <jeremy@sw.oz.au>
	6	* ELF version written by David Howells <David.Howells@nexor.co.uk>
	7	* Modified and incorporated into 2.3.x by Tigran Aivazian <tigran@veritas.com>
	8	* Support to dump vmalloc'd areas (ELF only), Tigran Aivazian <tigran@veritas.com>
	9	* Safe accesses to vmalloc/direct-mapped discontiguous areas, Kanoj Sarcar <kanoj@sgi.com>
	10	*/
	11
1da177e4 LT	12	#include <linux/mm.h>
	13	#include <linux/proc_fs.h>
	14	#include <linux/user.h>
16f7e0fe	15	#include <linux/capability.h>
1da177e4 LT	16	#include <linux/elf.h>
	17	#include <linux/elfcore.h>
	18	#include <linux/vmalloc.h>
	19	#include <linux/highmem.h>
	20	#include <linux/init.h>
	21	#include <asm/uaccess.h>
	22	#include <asm/io.h>
	23
36027604	24	#define CORE_STR "CORE"
1da177e4	25
79885b22 EI	26	#ifndef ELF_CORE_EFLAGS
	27	#define ELF_CORE_EFLAGS 0
	28	#endif
	29
97ce5d6d AD	30	static struct proc_dir_entry *proc_root_kcore;
97ce5d6d AD	31
1da177e4 LT	32	static int open_kcore(struct inode * inode, struct file * filp)
	33	{
	34	return capable(CAP_SYS_RAWIO) ? 0 : -EPERM;
	35	}
	36
	37	static ssize_t read_kcore(struct file , char __user , size_t, loff_t *);
	38
97ce5d6d	39	static const struct file_operations proc_kcore_operations = {
1da177e4 LT	40	.read = read_kcore,
	41	.open = open_kcore,
	42	};
	43
	44	#ifndef kc_vaddr_to_offset
	45	#define kc_vaddr_to_offset(v) ((v) - PAGE_OFFSET)
	46	#endif
	47	#ifndef kc_offset_to_vaddr
	48	#define kc_offset_to_vaddr(o) ((o) + PAGE_OFFSET)
	49	#endif
	50
1da177e4 LT	51	/* An ELF note in memory */
	52	struct memelfnote
	53	{
	54	const char *name;
	55	int type;
	56	unsigned int datasz;
	57	void *data;
	58	};
	59
	60	static struct kcore_list *kclist;
	61	static DEFINE_RWLOCK(kclist_lock);
	62
	63	void
	64	kclist_add(struct kcore_list new, void addr, size_t size)
	65	{
	66	new->addr = (unsigned long)addr;
	67	new->size = size;
	68
	69	write_lock(&kclist_lock);
	70	new->next = kclist;
	71	kclist = new;
	72	write_unlock(&kclist_lock);
	73	}
	74
	75	static size_t get_kcore_size(int nphdr, size_t elf_buflen)
	76	{
	77	size_t try, size;
	78	struct kcore_list *m;
	79
	80	nphdr = 1; / PT_NOTE */
	81	size = 0;
	82
	83	for (m=kclist; m; m=m->next) {
	84	try = kc_vaddr_to_offset((size_t)m->addr + m->size);
	85	if (try > size)
	86	size = try;
	87	nphdr = nphdr + 1;
	88	}
	89	*elf_buflen = sizeof(struct elfhdr) +
	90	(nphdr + 2)sizeof(struct elf_phdr) +
36027604 MD	91	3 * ((sizeof(struct elf_note)) +
	92	roundup(sizeof(CORE_STR), 4)) +
	93	roundup(sizeof(struct elf_prstatus), 4) +
	94	roundup(sizeof(struct elf_prpsinfo), 4) +
	95	roundup(sizeof(struct task_struct), 4);
1da177e4 LT	96	elf_buflen = PAGE_ALIGN(elf_buflen);
	97	return size + *elf_buflen;
	98	}
	99
	100
	101	/*****************************************************************************/
	102	/*
	103	* determine size of ELF note
	104	*/
	105	static int notesize(struct memelfnote *en)
	106	{
	107	int sz;
	108
	109	sz = sizeof(struct elf_note);
632dd205	110	sz += roundup((strlen(en->name) + 1), 4);
1da177e4 LT	111	sz += roundup(en->datasz, 4);
	112
	113	return sz;
	114	} /* end notesize() */
	115
	116	/*****************************************************************************/
	117	/*
	118	* store a note in the header buffer
	119	*/
	120	static char storenote(struct memelfnote men, char *bufp)
	121	{
	122	struct elf_note en;
	123
	124	#define DUMP_WRITE(addr,nr) do { memcpy(bufp,addr,nr); bufp += nr; } while(0)
	125
632dd205	126	en.n_namesz = strlen(men->name) + 1;
1da177e4 LT	127	en.n_descsz = men->datasz;
	128	en.n_type = men->type;
	129
	130	DUMP_WRITE(&en, sizeof(en));
	131	DUMP_WRITE(men->name, en.n_namesz);
	132
	133	/* XXX - cast from long long to long to avoid need for libgcc.a */
	134	bufp = (char*) roundup((unsigned long)bufp,4);
	135	DUMP_WRITE(men->data, men->datasz);
	136	bufp = (char*) roundup((unsigned long)bufp,4);
	137
	138	#undef DUMP_WRITE
	139
	140	return bufp;
	141	} /* end storenote() */
	142
	143	/*
	144	* store an ELF coredump header in the supplied buffer
	145	* nphdr is the number of elf_phdr to insert
	146	*/
	147	static void elf_kcore_store_hdr(char *bufp, int nphdr, int dataoff)
	148	{
	149	struct elf_prstatus prstatus; /* NT_PRSTATUS */
	150	struct elf_prpsinfo prpsinfo; /* NT_PRPSINFO */
	151	struct elf_phdr nhdr, phdr;
	152	struct elfhdr *elf;
	153	struct memelfnote notes[3];
	154	off_t offset = 0;
	155	struct kcore_list *m;
	156
	157	/* setup ELF header */
	158	elf = (struct elfhdr *) bufp;
	159	bufp += sizeof(struct elfhdr);
	160	offset += sizeof(struct elfhdr);
	161	memcpy(elf->e_ident, ELFMAG, SELFMAG);
	162	elf->e_ident[EI_CLASS] = ELF_CLASS;
	163	elf->e_ident[EI_DATA] = ELF_DATA;
	164	elf->e_ident[EI_VERSION]= EV_CURRENT;
	165	elf->e_ident[EI_OSABI] = ELF_OSABI;
	166	memset(elf->e_ident+EI_PAD, 0, EI_NIDENT-EI_PAD);
	167	elf->e_type = ET_CORE;
	168	elf->e_machine = ELF_ARCH;
	169	elf->e_version = EV_CURRENT;
	170	elf->e_entry = 0;
	171	elf->e_phoff = sizeof(struct elfhdr);
	172	elf->e_shoff = 0;
79885b22	173	elf->e_flags = ELF_CORE_EFLAGS;
1da177e4 LT	174	elf->e_ehsize = sizeof(struct elfhdr);
	175	elf->e_phentsize= sizeof(struct elf_phdr);
	176	elf->e_phnum = nphdr;
	177	elf->e_shentsize= 0;
	178	elf->e_shnum = 0;
	179	elf->e_shstrndx = 0;
	180
	181	/* setup ELF PT_NOTE program header */
	182	nhdr = (struct elf_phdr *) bufp;
	183	bufp += sizeof(struct elf_phdr);
	184	offset += sizeof(struct elf_phdr);
	185	nhdr->p_type = PT_NOTE;
	186	nhdr->p_offset = 0;
	187	nhdr->p_vaddr = 0;
	188	nhdr->p_paddr = 0;
	189	nhdr->p_filesz = 0;
	190	nhdr->p_memsz = 0;
	191	nhdr->p_flags = 0;
	192	nhdr->p_align = 0;
	193
	194	/* setup ELF PT_LOAD program header for every area */
	195	for (m=kclist; m; m=m->next) {
	196	phdr = (struct elf_phdr *) bufp;
	197	bufp += sizeof(struct elf_phdr);
	198	offset += sizeof(struct elf_phdr);
	199
	200	phdr->p_type = PT_LOAD;
	201	phdr->p_flags = PF_R\|PF_W\|PF_X;
	202	phdr->p_offset = kc_vaddr_to_offset(m->addr) + dataoff;
	203	phdr->p_vaddr = (size_t)m->addr;
	204	phdr->p_paddr = 0;
	205	phdr->p_filesz = phdr->p_memsz = m->size;
	206	phdr->p_align = PAGE_SIZE;
	207	}
	208
	209	/*
	210	* Set up the notes in similar form to SVR4 core dumps made
	211	* with info from their /proc.
	212	*/
	213	nhdr->p_offset = offset;
	214
	215	/* set up the process status */
36027604	216	notes[0].name = CORE_STR;
1da177e4 LT	217	notes[0].type = NT_PRSTATUS;
	218	notes[0].datasz = sizeof(struct elf_prstatus);
	219	notes[0].data = &prstatus;
	220
	221	memset(&prstatus, 0, sizeof(struct elf_prstatus));
	222
	223	nhdr->p_filesz = notesize(&notes[0]);
	224	bufp = storenote(&notes[0], bufp);
	225
	226	/* set up the process info */
36027604	227	notes[1].name = CORE_STR;
1da177e4 LT	228	notes[1].type = NT_PRPSINFO;
	229	notes[1].datasz = sizeof(struct elf_prpsinfo);
	230	notes[1].data = &prpsinfo;
	231
	232	memset(&prpsinfo, 0, sizeof(struct elf_prpsinfo));
	233	prpsinfo.pr_state = 0;
	234	prpsinfo.pr_sname = 'R';
	235	prpsinfo.pr_zomb = 0;
	236
	237	strcpy(prpsinfo.pr_fname, "vmlinux");
	238	strncpy(prpsinfo.pr_psargs, saved_command_line, ELF_PRARGSZ);
	239
	240	nhdr->p_filesz += notesize(&notes[1]);
	241	bufp = storenote(&notes[1], bufp);
	242
	243	/* set up the task structure */
36027604	244	notes[2].name = CORE_STR;
1da177e4 LT	245	notes[2].type = NT_TASKSTRUCT;
	246	notes[2].datasz = sizeof(struct task_struct);
	247	notes[2].data = current;
	248
	249	nhdr->p_filesz += notesize(&notes[2]);
	250	bufp = storenote(&notes[2], bufp);
	251
	252	} /* end elf_kcore_store_hdr() */
	253
	254	/*****************************************************************************/
	255	/*
	256	* read from the ELF header and then kernel memory
	257	*/
	258	static ssize_t
	259	read_kcore(struct file file, char __user buffer, size_t buflen, loff_t *fpos)
	260	{
	261	ssize_t acc = 0;
	262	size_t size, tsz;
	263	size_t elf_buflen;
	264	int nphdr;
	265	unsigned long start;
	266
	267	read_lock(&kclist_lock);
	268	proc_root_kcore->size = size = get_kcore_size(&nphdr, &elf_buflen);
	269	if (buflen == 0 \|\| *fpos >= size) {
	270	read_unlock(&kclist_lock);
	271	return 0;
	272	}
	273
	274	/* trim buflen to not go beyond EOF */
	275	if (buflen > size - *fpos)
	276	buflen = size - *fpos;
	277
	278	/* construct an ELF core header if we'll need some of it */
	279	if (*fpos < elf_buflen) {
	280	char * elf_buf;
	281
	282	tsz = elf_buflen - *fpos;
	283	if (buflen < tsz)
	284	tsz = buflen;
f8314dc6	285	elf_buf = kzalloc(elf_buflen, GFP_ATOMIC);
1da177e4 LT	286	if (!elf_buf) {
	287	read_unlock(&kclist_lock);
	288	return -ENOMEM;
	289	}
1da177e4 LT	290	elf_kcore_store_hdr(elf_buf, nphdr, elf_buflen);
	291	read_unlock(&kclist_lock);
	292	if (copy_to_user(buffer, elf_buf + *fpos, tsz)) {
	293	kfree(elf_buf);
	294	return -EFAULT;
	295	}
	296	kfree(elf_buf);
	297	buflen -= tsz;
	298	*fpos += tsz;
	299	buffer += tsz;
	300	acc += tsz;
	301
	302	/* leave now if filled buffer already */
	303	if (buflen == 0)
	304	return acc;
	305	} else
	306	read_unlock(&kclist_lock);
	307
	308	/*
	309	* Check to see if our file offset matches with any of
	310	* the addresses in the elf_phdr on our list.
	311	*/
	312	start = kc_offset_to_vaddr(*fpos - elf_buflen);
	313	if ((tsz = (PAGE_SIZE - (start & ~PAGE_MASK))) > buflen)
	314	tsz = buflen;
	315
	316	while (buflen) {
	317	struct kcore_list *m;
	318
	319	read_lock(&kclist_lock);
	320	for (m=kclist; m; m=m->next) {
	321	if (start >= m->addr && start < (m->addr+m->size))
	322	break;
	323	}
	324	read_unlock(&kclist_lock);
	325
	326	if (m == NULL) {
	327	if (clear_user(buffer, tsz))
	328	return -EFAULT;
9e2779fa	329	} else if (is_vmalloc_addr((void *)start)) {
1da177e4	330	char * elf_buf;
1da177e4	331
f8314dc6	332	elf_buf = kzalloc(tsz, GFP_KERNEL);
1da177e4 LT	333	if (!elf_buf)
1da177e4 LT	334	return -ENOMEM;
73d7c33e KH	335	vread(elf_buf, (char *)start, tsz);
73d7c33e KH	336	/* we have to zero-fill user buffer even if no read */
1da177e4 LT	337	if (copy_to_user(buffer, elf_buf, tsz)) {
	338	kfree(elf_buf);
	339	return -EFAULT;
	340	}
	341	kfree(elf_buf);
	342	} else {
	343	if (kern_addr_valid(start)) {
	344	unsigned long n;
	345
	346	n = copy_to_user(buffer, (char *)start, tsz);
	347	/*
	348	* We cannot distingush between fault on source
	349	* and fault on destination. When this happens
	350	* we clear too and hope it will trigger the
	351	* EFAULT again.
	352	*/
	353	if (n) {
	354	if (clear_user(buffer + tsz - n,
0635170b	355	n))
1da177e4 LT	356	return -EFAULT;
	357	}
	358	} else {
	359	if (clear_user(buffer, tsz))
	360	return -EFAULT;
	361	}
	362	}
	363	buflen -= tsz;
	364	*fpos += tsz;
	365	buffer += tsz;
	366	acc += tsz;
	367	start += tsz;
	368	tsz = (buflen > PAGE_SIZE ? PAGE_SIZE : buflen);
	369	}
	370
	371	return acc;
	372	}
97ce5d6d AD	373
	374	static int __init proc_kcore_init(void)
	375	{
	376	proc_root_kcore = proc_create("kcore", S_IRUSR, NULL, &proc_kcore_operations);
	377	if (proc_root_kcore)
	378	proc_root_kcore->size =
	379	(size_t)high_memory - PAGE_OFFSET + PAGE_SIZE;
	380	return 0;
	381	}
	382	module_init(proc_kcore_init);