[linux-block.git] / kernel / kallsyms.c

/*
 * kallsyms.c: in-kernel printing of symbolic oopses and stack traces.
 *
 * Rewritten and vastly simplified by Rusty Russell for in-kernel
 * module loader:
 *   Copyright 2002 Rusty Russell <rusty@rustcorp.com.au> IBM Corporation
 *
 * ChangeLog:
 *
 * (25/Aug/2004) Paulo Marques <pmarques@grupopie.com>
 *      Changed the compression method from stem compression to "table lookup"
 *      compression (see scripts/kallsyms.c for a more complete description)
 */
#include <linux/kallsyms.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/seq_file.h>
#include <linux/fs.h>
#include <linux/err.h>
#include <linux/proc_fs.h>
#include <linux/sched.h>	/* for cond_resched */
#include <linux/mm.h>
#include <linux/ctype.h>

#include <asm/sections.h>

#ifdef CONFIG_KALLSYMS_ALL
#define all_var 1
#else
#define all_var 0
#endif

/* These will be re-linked against their real values during the second link stage */
extern unsigned long kallsyms_addresses[] __attribute__((weak));
extern unsigned long kallsyms_num_syms __attribute__((weak,section("data")));
extern u8 kallsyms_names[] __attribute__((weak));

extern u8 kallsyms_token_table[] __attribute__((weak));
extern u16 kallsyms_token_index[] __attribute__((weak));

extern unsigned long kallsyms_markers[] __attribute__((weak));

static inline int is_kernel_inittext(unsigned long addr)
{
	if (addr >= (unsigned long)_sinittext
	    && addr <= (unsigned long)_einittext)
		return 1;
	return 0;
}

static inline int is_kernel_extratext(unsigned long addr)
{
	if (addr >= (unsigned long)_sextratext
	    && addr <= (unsigned long)_eextratext)
		return 1;
	return 0;
}

static inline int is_kernel_text(unsigned long addr)
{
	if (addr >= (unsigned long)_stext && addr <= (unsigned long)_etext)
		return 1;
	return in_gate_area_no_task(addr);
}

static inline int is_kernel(unsigned long addr)
{
	if (addr >= (unsigned long)_stext && addr <= (unsigned long)_end)
		return 1;
	return in_gate_area_no_task(addr);
}

static int is_ksym_addr(unsigned long addr)
{
	if (all_var)
		return is_kernel(addr);

	return is_kernel_text(addr) || is_kernel_inittext(addr) ||
		is_kernel_extratext(addr);
}

/* expand a compressed symbol data into the resulting uncompressed string,
   given the offset to where the symbol is in the compressed stream */
static unsigned int kallsyms_expand_symbol(unsigned int off, char *result)
{
	int len, skipped_first = 0;
	u8 *tptr, *data;

	/* get the compressed symbol length from the first symbol byte */
	data = &kallsyms_names[off];
	len = *data;
	data++;

	/* update the offset to return the offset for the next symbol on
	 * the compressed stream */
	off += len + 1;

	/* for every byte on the compressed symbol data, copy the table
	   entry for that byte */
	while(len) {
		tptr = &kallsyms_token_table[ kallsyms_token_index[*data] ];
		data++;
		len--;

		while (*tptr) {
			if(skipped_first) {
				*result = *tptr;
				result++;
			} else
				skipped_first = 1;
			tptr++;
		}
	}

	*result = '\0';

	/* return to offset to the next symbol */
	return off;
}

/* get symbol type information. This is encoded as a single char at the
 * begining of the symbol name */
static char kallsyms_get_symbol_type(unsigned int off)
{
	/* get just the first code, look it up in the token table, and return the
	 * first char from this token */
	return kallsyms_token_table[ kallsyms_token_index[ kallsyms_names[off+1] ] ];
}


/* find the offset on the compressed stream given and index in the
 * kallsyms array */
static unsigned int get_symbol_offset(unsigned long pos)
{
	u8 *name;
	int i;

	/* use the closest marker we have. We have markers every 256 positions,
	 * so that should be close enough */
	name = &kallsyms_names[ kallsyms_markers[pos>>8] ];

	/* sequentially scan all the symbols up to the point we're searching for.
	 * Every symbol is stored in a [<len>][<len> bytes of data] format, so we
	 * just need to add the len to the current pointer for every symbol we
	 * wish to skip */
	for(i = 0; i < (pos&0xFF); i++)
		name = name + (*name) + 1;

	return name - kallsyms_names;
}

/* Lookup the address for this symbol. Returns 0 if not found. */
unsigned long kallsyms_lookup_name(const char *name)
{
	char namebuf[KSYM_NAME_LEN+1];
	unsigned long i;
	unsigned int off;

	for (i = 0, off = 0; i < kallsyms_num_syms; i++) {
		off = kallsyms_expand_symbol(off, namebuf);

		if (strcmp(namebuf, name) == 0)
			return kallsyms_addresses[i];
	}
	return module_kallsyms_lookup_name(name);
}

static unsigned long get_symbol_pos(unsigned long addr,
				    unsigned long *symbolsize,
				    unsigned long *offset)
{
	unsigned long symbol_start = 0, symbol_end = 0;
	unsigned long i, low, high, mid;

	/* This kernel should never had been booted. */
	BUG_ON(!kallsyms_addresses);

	/* do a binary search on the sorted kallsyms_addresses array */
	low = 0;
	high = kallsyms_num_syms;

	while (high - low > 1) {
		mid = (low + high) / 2;
		if (kallsyms_addresses[mid] <= addr)
			low = mid;
		else
			high = mid;
	}

	/*
	 * search for the first aliased symbol. Aliased
	 * symbols are symbols with the same address
	 */
	while (low && kallsyms_addresses[low-1] == kallsyms_addresses[low])
		--low;

	symbol_start = kallsyms_addresses[low];

	/* Search for next non-aliased symbol */
	for (i = low + 1; i < kallsyms_num_syms; i++) {
		if (kallsyms_addresses[i] > symbol_start) {
			symbol_end = kallsyms_addresses[i];
			break;
		}
	}

	/* if we found no next symbol, we use the end of the section */
	if (!symbol_end) {
		if (is_kernel_inittext(addr))
			symbol_end = (unsigned long)_einittext;
		else if (all_var)
			symbol_end = (unsigned long)_end;
		else
			symbol_end = (unsigned long)_etext;
	}

	*symbolsize = symbol_end - symbol_start;
	*offset = addr - symbol_start;

	return low;
}

/*
 * Lookup an address but don't bother to find any names.
 */
int kallsyms_lookup_size_offset(unsigned long addr, unsigned long *symbolsize,
				unsigned long *offset)
{
	if (is_ksym_addr(addr))
		return !!get_symbol_pos(addr, symbolsize, offset);

	return !!module_address_lookup(addr, symbolsize, offset, NULL);
}

/*
 * Lookup an address
 * - modname is set to NULL if it's in the kernel
 * - we guarantee that the returned name is valid until we reschedule even if
 *   it resides in a module
 * - we also guarantee that modname will be valid until rescheduled
 */
const char *kallsyms_lookup(unsigned long addr,
			    unsigned long *symbolsize,
			    unsigned long *offset,
			    char **modname, char *namebuf)
{
	const char *msym;

	namebuf[KSYM_NAME_LEN] = 0;
	namebuf[0] = 0;

	if (is_ksym_addr(addr)) {
		unsigned long pos;

		pos = get_symbol_pos(addr, symbolsize, offset);
		/* Grab name */
		kallsyms_expand_symbol(get_symbol_offset(pos), namebuf);
		*modname = NULL;
		return namebuf;
	}

	/* see if it's in a module */
	msym = module_address_lookup(addr, symbolsize, offset, modname);
	if (msym)
		return strncpy(namebuf, msym, KSYM_NAME_LEN);

	return NULL;
}

/* Replace "%s" in format with address, or returns -errno. */
void __print_symbol(const char *fmt, unsigned long address)
{
	char *modname;
	const char *name;
	unsigned long offset, size;
	char namebuf[KSYM_NAME_LEN+1];
	char buffer[sizeof("%s+%#lx/%#lx [%s]") + KSYM_NAME_LEN +
		    2*(BITS_PER_LONG*3/10) + MODULE_NAME_LEN + 1];

	name = kallsyms_lookup(address, &size, &offset, &modname, namebuf);

	if (!name)
		sprintf(buffer, "0x%lx", address);
	else {
		if (modname)
			sprintf(buffer, "%s+%#lx/%#lx [%s]", name, offset,
				size, modname);
		else
			sprintf(buffer, "%s+%#lx/%#lx", name, offset, size);
	}
	printk(fmt, buffer);
}

/* To avoid using get_symbol_offset for every symbol, we carry prefix along. */
struct kallsym_iter
{
	loff_t pos;
	struct module *owner;
	unsigned long value;
	unsigned int nameoff; /* If iterating in core kernel symbols */
	char type;
	char name[KSYM_NAME_LEN+1];
};

static int get_ksymbol_mod(struct kallsym_iter *iter)
{
	iter->owner = module_get_kallsym(iter->pos - kallsyms_num_syms,
					 &iter->value, &iter->type,
					 iter->name, sizeof(iter->name));
	if (iter->owner == NULL)
		return 0;

	/* Label it "global" if it is exported, "local" if not exported. */
	iter->type = is_exported(iter->name, iter->owner)
		? toupper(iter->type) : tolower(iter->type);

	return 1;
}

/* Returns space to next name. */
static unsigned long get_ksymbol_core(struct kallsym_iter *iter)
{
	unsigned off = iter->nameoff;

	iter->owner = NULL;
	iter->value = kallsyms_addresses[iter->pos];

	iter->type = kallsyms_get_symbol_type(off);

	off = kallsyms_expand_symbol(off, iter->name);

	return off - iter->nameoff;
}

static void reset_iter(struct kallsym_iter *iter, loff_t new_pos)
{
	iter->name[0] = '\0';
	iter->nameoff = get_symbol_offset(new_pos);
	iter->pos = new_pos;
}

/* Returns false if pos at or past end of file. */
static int update_iter(struct kallsym_iter *iter, loff_t pos)
{
	/* Module symbols can be accessed randomly. */
	if (pos >= kallsyms_num_syms) {
		iter->pos = pos;
		return get_ksymbol_mod(iter);
	}
	
	/* If we're not on the desired position, reset to new position. */
	if (pos != iter->pos)
		reset_iter(iter, pos);

	iter->nameoff += get_ksymbol_core(iter);
	iter->pos++;

	return 1;
}

static void *s_next(struct seq_file *m, void *p, loff_t *pos)
{
	(*pos)++;

	if (!update_iter(m->private, *pos))
		return NULL;
	return p;
}

static void *s_start(struct seq_file *m, loff_t *pos)
{
	if (!update_iter(m->private, *pos))
		return NULL;
	return m->private;
}

static void s_stop(struct seq_file *m, void *p)
{
}

static int s_show(struct seq_file *m, void *p)
{
	struct kallsym_iter *iter = m->private;

	/* Some debugging symbols have no name.  Ignore them. */ 
	if (!iter->name[0])
		return 0;

	if (iter->owner)
		seq_printf(m, "%0*lx %c %s\t[%s]\n",
			   (int)(2*sizeof(void*)),
			   iter->value, iter->type, iter->name,
			   module_name(iter->owner));
	else
		seq_printf(m, "%0*lx %c %s\n",
			   (int)(2*sizeof(void*)),
			   iter->value, iter->type, iter->name);
	return 0;
}

static const struct seq_operations kallsyms_op = {
	.start = s_start,
	.next = s_next,
	.stop = s_stop,
	.show = s_show
};

static int kallsyms_open(struct inode *inode, struct file *file)
{
	/* We keep iterator in m->private, since normal case is to
	 * s_start from where we left off, so we avoid doing
	 * using get_symbol_offset for every symbol */
	struct kallsym_iter *iter;
	int ret;

	iter = kmalloc(sizeof(*iter), GFP_KERNEL);
	if (!iter)
		return -ENOMEM;
	reset_iter(iter, 0);

	ret = seq_open(file, &kallsyms_op);
	if (ret == 0)
		((struct seq_file *)file->private_data)->private = iter;
	else
		kfree(iter);
	return ret;
}

static int kallsyms_release(struct inode *inode, struct file *file)
{
	struct seq_file *m = (struct seq_file *)file->private_data;
	kfree(m->private);
	return seq_release(inode, file);
}

static const struct file_operations kallsyms_operations = {
	.open = kallsyms_open,
	.read = seq_read,
	.llseek = seq_lseek,
	.release = kallsyms_release,
};

static int __init kallsyms_init(void)
{
	struct proc_dir_entry *entry;

	entry = create_proc_entry("kallsyms", 0444, NULL);
	if (entry)
		entry->proc_fops = &kallsyms_operations;
	return 0;
}
__initcall(kallsyms_init);

EXPORT_SYMBOL(__print_symbol);
Commit	Line	Data
1da177e4 LT	1	/*
	2	* kallsyms.c: in-kernel printing of symbolic oopses and stack traces.
	3	*
	4	* Rewritten and vastly simplified by Rusty Russell for in-kernel
	5	* module loader:
	6	* Copyright 2002 Rusty Russell <rusty@rustcorp.com.au> IBM Corporation
	7	*
	8	* ChangeLog:
	9	*
	10	* (25/Aug/2004) Paulo Marques <pmarques@grupopie.com>
	11	* Changed the compression method from stem compression to "table lookup"
	12	* compression (see scripts/kallsyms.c for a more complete description)
	13	*/
	14	#include <linux/kallsyms.h>
	15	#include <linux/module.h>
	16	#include <linux/init.h>
	17	#include <linux/seq_file.h>
	18	#include <linux/fs.h>
	19	#include <linux/err.h>
	20	#include <linux/proc_fs.h>
4e57b681	21	#include <linux/sched.h> /* for cond_resched */
1da177e4	22	#include <linux/mm.h>
07354a00	23	#include <linux/ctype.h>
1da177e4 LT	24
	25	#include <asm/sections.h>
	26
	27	#ifdef CONFIG_KALLSYMS_ALL
	28	#define all_var 1
	29	#else
	30	#define all_var 0
	31	#endif
	32
	33	/* These will be re-linked against their real values during the second link stage */
	34	extern unsigned long kallsyms_addresses[] __attribute__((weak));
	35	extern unsigned long kallsyms_num_syms __attribute__((weak,section("data")));
	36	extern u8 kallsyms_names[] __attribute__((weak));
	37
	38	extern u8 kallsyms_token_table[] __attribute__((weak));
	39	extern u16 kallsyms_token_index[] __attribute__((weak));
	40
	41	extern unsigned long kallsyms_markers[] __attribute__((weak));
	42
	43	static inline int is_kernel_inittext(unsigned long addr)
	44	{
	45	if (addr >= (unsigned long)_sinittext
	46	&& addr <= (unsigned long)_einittext)
	47	return 1;
	48	return 0;
	49	}
	50
075d6eb1 DW	51	static inline int is_kernel_extratext(unsigned long addr)
	52	{
	53	if (addr >= (unsigned long)_sextratext
	54	&& addr <= (unsigned long)_eextratext)
	55	return 1;
	56	return 0;
	57	}
	58
1da177e4 LT	59	static inline int is_kernel_text(unsigned long addr)
	60	{
	61	if (addr >= (unsigned long)_stext && addr <= (unsigned long)_etext)
	62	return 1;
	63	return in_gate_area_no_task(addr);
	64	}
	65
	66	static inline int is_kernel(unsigned long addr)
	67	{
	68	if (addr >= (unsigned long)_stext && addr <= (unsigned long)_end)
	69	return 1;
	70	return in_gate_area_no_task(addr);
	71	}
	72
ffc50891 FBH	73	static int is_ksym_addr(unsigned long addr)
	74	{
	75	if (all_var)
	76	return is_kernel(addr);
	77
	78	return is_kernel_text(addr) \|\| is_kernel_inittext(addr) \|\|
	79	is_kernel_extratext(addr);
	80	}
	81
1da177e4 LT	82	/* expand a compressed symbol data into the resulting uncompressed string,
	83	given the offset to where the symbol is in the compressed stream */
	84	static unsigned int kallsyms_expand_symbol(unsigned int off, char *result)
	85	{
	86	int len, skipped_first = 0;
	87	u8 tptr, data;
	88
	89	/* get the compressed symbol length from the first symbol byte */
	90	data = &kallsyms_names[off];
	91	len = *data;
	92	data++;
	93
	94	/* update the offset to return the offset for the next symbol on
	95	* the compressed stream */
	96	off += len + 1;
	97
	98	/* for every byte on the compressed symbol data, copy the table
	99	entry for that byte */
	100	while(len) {
	101	tptr = &kallsyms_token_table[ kallsyms_token_index[*data] ];
	102	data++;
	103	len--;
	104
	105	while (*tptr) {
	106	if(skipped_first) {
	107	result = tptr;
	108	result++;
	109	} else
	110	skipped_first = 1;
	111	tptr++;
	112	}
	113	}
	114
	115	*result = '\0';
	116
	117	/* return to offset to the next symbol */
	118	return off;
	119	}
	120
	121	/* get symbol type information. This is encoded as a single char at the
	122	* begining of the symbol name */
	123	static char kallsyms_get_symbol_type(unsigned int off)
	124	{
	125	/* get just the first code, look it up in the token table, and return the
	126	* first char from this token */
	127	return kallsyms_token_table[ kallsyms_token_index[ kallsyms_names[off+1] ] ];
	128	}
	129
	130
	131	/* find the offset on the compressed stream given and index in the
	132	* kallsyms array */
	133	static unsigned int get_symbol_offset(unsigned long pos)
	134	{
	135	u8 *name;
	136	int i;
	137
	138	/* use the closest marker we have. We have markers every 256 positions,
	139	* so that should be close enough */
	140	name = &kallsyms_names[ kallsyms_markers[pos>>8] ];
	141
	142	/* sequentially scan all the symbols up to the point we're searching for.
	143	* Every symbol is stored in a [<len>][<len> bytes of data] format, so we
	144	* just need to add the len to the current pointer for every symbol we
	145	* wish to skip */
146	for(i = 0; i < (pos&0xFF); i++)
147	name = name + (*name) + 1;
148
149	return name - kallsyms_names;
150	}
151
152	/* Lookup the address for this symbol. Returns 0 if not found. */
153	unsigned long kallsyms_lookup_name(const char *name)
154	{
155	char namebuf[KSYM_NAME_LEN+1];
156	unsigned long i;
157	unsigned int off;
158
159	for (i = 0, off = 0; i < kallsyms_num_syms; i++) {
160	off = kallsyms_expand_symbol(off, namebuf);
161
162	if (strcmp(namebuf, name) == 0)
163	return kallsyms_addresses[i];
164	}
165	return module_kallsyms_lookup_name(name);
166	}
1da177e4	167
ffc50891 FBH	168	static unsigned long get_symbol_pos(unsigned long addr,
	169	unsigned long *symbolsize,
	170	unsigned long *offset)
	171	{
	172	unsigned long symbol_start = 0, symbol_end = 0;
	173	unsigned long i, low, high, mid;
	174
	175	/* This kernel should never had been booted. */
	176	BUG_ON(!kallsyms_addresses);
	177
	178	/* do a binary search on the sorted kallsyms_addresses array */
	179	low = 0;
	180	high = kallsyms_num_syms;
	181
	182	while (high - low > 1) {
	183	mid = (low + high) / 2;
	184	if (kallsyms_addresses[mid] <= addr)
	185	low = mid;
	186	else
	187	high = mid;
	188	}
	189
	190	/*
	191	* search for the first aliased symbol. Aliased
	192	* symbols are symbols with the same address
	193	*/
	194	while (low && kallsyms_addresses[low-1] == kallsyms_addresses[low])
	195	--low;
	196
	197	symbol_start = kallsyms_addresses[low];
	198
	199	/* Search for next non-aliased symbol */
	200	for (i = low + 1; i < kallsyms_num_syms; i++) {
	201	if (kallsyms_addresses[i] > symbol_start) {
	202	symbol_end = kallsyms_addresses[i];
	203	break;
	204	}
	205	}
	206
	207	/* if we found no next symbol, we use the end of the section */
	208	if (!symbol_end) {
	209	if (is_kernel_inittext(addr))
	210	symbol_end = (unsigned long)_einittext;
	211	else if (all_var)
	212	symbol_end = (unsigned long)_end;
	213	else
	214	symbol_end = (unsigned long)_etext;
	215	}
	216
	217	*symbolsize = symbol_end - symbol_start;
	218	*offset = addr - symbol_start;
	219
	220	return low;
	221	}
	222
	223	/*
	224	* Lookup an address but don't bother to find any names.
	225	*/
	226	int kallsyms_lookup_size_offset(unsigned long addr, unsigned long *symbolsize,
	227	unsigned long *offset)
	228	{
	229	if (is_ksym_addr(addr))
	230	return !!get_symbol_pos(addr, symbolsize, offset);
	231
232	return !!module_address_lookup(addr, symbolsize, offset, NULL);
233	}
234
1da177e4 LT	235	/*
	236	* Lookup an address
	237	* - modname is set to NULL if it's in the kernel
	238	* - we guarantee that the returned name is valid until we reschedule even if
	239	* it resides in a module
	240	* - we also guarantee that modname will be valid until rescheduled
	241	*/
	242	const char *kallsyms_lookup(unsigned long addr,
	243	unsigned long *symbolsize,
	244	unsigned long *offset,
	245	char *modname, char namebuf)
	246	{
1da177e4 LT	247	const char *msym;
1da177e4 LT	248
1da177e4 LT	249	namebuf[KSYM_NAME_LEN] = 0;
	250	namebuf[0] = 0;
	251
ffc50891 FBH	252	if (is_ksym_addr(addr)) {
ffc50891 FBH	253	unsigned long pos;
1da177e4	254
ffc50891	255	pos = get_symbol_pos(addr, symbolsize, offset);
1da177e4	256	/* Grab name */
ffc50891	257	kallsyms_expand_symbol(get_symbol_offset(pos), namebuf);
1da177e4	258	*modname = NULL;
1da177e4 LT	259	return namebuf;
	260	}
	261
	262	/* see if it's in a module */
	263	msym = module_address_lookup(addr, symbolsize, offset, modname);
	264	if (msym)
	265	return strncpy(namebuf, msym, KSYM_NAME_LEN);
	266
	267	return NULL;
	268	}
	269
	270	/* Replace "%s" in format with address, or returns -errno. */
	271	void __print_symbol(const char *fmt, unsigned long address)
	272	{
	273	char *modname;
	274	const char *name;
	275	unsigned long offset, size;
	276	char namebuf[KSYM_NAME_LEN+1];
	277	char buffer[sizeof("%s+%#lx/%#lx [%s]") + KSYM_NAME_LEN +
	278	2(BITS_PER_LONG3/10) + MODULE_NAME_LEN + 1];
	279
	280	name = kallsyms_lookup(address, &size, &offset, &modname, namebuf);
	281
	282	if (!name)
	283	sprintf(buffer, "0x%lx", address);
	284	else {
	285	if (modname)
	286	sprintf(buffer, "%s+%#lx/%#lx [%s]", name, offset,
	287	size, modname);
	288	else
	289	sprintf(buffer, "%s+%#lx/%#lx", name, offset, size);
	290	}
	291	printk(fmt, buffer);
	292	}
	293
	294	/* To avoid using get_symbol_offset for every symbol, we carry prefix along. */
	295	struct kallsym_iter
	296	{
	297	loff_t pos;
	298	struct module *owner;
	299	unsigned long value;
	300	unsigned int nameoff; /* If iterating in core kernel symbols */
	301	char type;
	302	char name[KSYM_NAME_LEN+1];
	303	};
	304
1da177e4 LT	305	static int get_ksymbol_mod(struct kallsym_iter *iter)
	306	{
	307	iter->owner = module_get_kallsym(iter->pos - kallsyms_num_syms,
098c5eea AG	308	&iter->value, &iter->type,
098c5eea AG	309	iter->name, sizeof(iter->name));
1da177e4 LT	310	if (iter->owner == NULL)
	311	return 0;
	312
07354a00 AJ	313	/* Label it "global" if it is exported, "local" if not exported. */
	314	iter->type = is_exported(iter->name, iter->owner)
	315	? toupper(iter->type) : tolower(iter->type);
	316
1da177e4 LT	317	return 1;
	318	}
	319
	320	/* Returns space to next name. */
	321	static unsigned long get_ksymbol_core(struct kallsym_iter *iter)
	322	{
	323	unsigned off = iter->nameoff;
	324
	325	iter->owner = NULL;
	326	iter->value = kallsyms_addresses[iter->pos];
	327
	328	iter->type = kallsyms_get_symbol_type(off);
	329
	330	off = kallsyms_expand_symbol(off, iter->name);
	331
	332	return off - iter->nameoff;
	333	}
	334
	335	static void reset_iter(struct kallsym_iter *iter, loff_t new_pos)
	336	{
	337	iter->name[0] = '\0';
	338	iter->nameoff = get_symbol_offset(new_pos);
	339	iter->pos = new_pos;
	340	}
	341
	342	/* Returns false if pos at or past end of file. */
	343	static int update_iter(struct kallsym_iter *iter, loff_t pos)
	344	{
	345	/* Module symbols can be accessed randomly. */
	346	if (pos >= kallsyms_num_syms) {
	347	iter->pos = pos;
	348	return get_ksymbol_mod(iter);
	349	}
	350
	351	/* If we're not on the desired position, reset to new position. */
	352	if (pos != iter->pos)
	353	reset_iter(iter, pos);
	354
	355	iter->nameoff += get_ksymbol_core(iter);
	356	iter->pos++;
	357
	358	return 1;
	359	}
	360
	361	static void s_next(struct seq_file m, void p, loff_t pos)
	362	{
	363	(*pos)++;
	364
	365	if (!update_iter(m->private, *pos))
	366	return NULL;
	367	return p;
	368	}
	369
	370	static void s_start(struct seq_file m, loff_t *pos)
	371	{
	372	if (!update_iter(m->private, *pos))
	373	return NULL;
	374	return m->private;
	375	}
	376
	377	static void s_stop(struct seq_file m, void p)
	378	{
	379	}
	380
381	static int s_show(struct seq_file m, void p)
382	{
383	struct kallsym_iter *iter = m->private;
384
385	/* Some debugging symbols have no name. Ignore them. */
386	if (!iter->name[0])
387	return 0;
388
389	if (iter->owner)
390	seq_printf(m, "%0*lx %c %s\t[%s]\n",
391	(int)(2sizeof(void)),
392	iter->value, iter->type, iter->name,
393	module_name(iter->owner));
394	else
395	seq_printf(m, "%0*lx %c %s\n",
396	(int)(2sizeof(void)),
397	iter->value, iter->type, iter->name);
398	return 0;
399	}
400
15ad7cdc	401	static const struct seq_operations kallsyms_op = {
1da177e4 LT	402	.start = s_start,
	403	.next = s_next,
	404	.stop = s_stop,
	405	.show = s_show
	406	};
	407
	408	static int kallsyms_open(struct inode inode, struct file file)
	409	{
	410	/* We keep iterator in m->private, since normal case is to
	411	* s_start from where we left off, so we avoid doing
	412	* using get_symbol_offset for every symbol */
	413	struct kallsym_iter *iter;
	414	int ret;
	415
	416	iter = kmalloc(sizeof(*iter), GFP_KERNEL);
	417	if (!iter)
	418	return -ENOMEM;
	419	reset_iter(iter, 0);
	420
	421	ret = seq_open(file, &kallsyms_op);
	422	if (ret == 0)
	423	((struct seq_file *)file->private_data)->private = iter;
	424	else
	425	kfree(iter);
	426	return ret;
	427	}
	428
	429	static int kallsyms_release(struct inode inode, struct file file)
	430	{
	431	struct seq_file m = (struct seq_file )file->private_data;
	432	kfree(m->private);
	433	return seq_release(inode, file);
	434	}
	435
15ad7cdc	436	static const struct file_operations kallsyms_operations = {
1da177e4 LT	437	.open = kallsyms_open,
	438	.read = seq_read,
	439	.llseek = seq_lseek,
	440	.release = kallsyms_release,
	441	};
	442
	443	static int __init kallsyms_init(void)
	444	{
	445	struct proc_dir_entry *entry;
	446
	447	entry = create_proc_entry("kallsyms", 0444, NULL);
	448	if (entry)
	449	entry->proc_fops = &kallsyms_operations;
	450	return 0;
	451	}
	452	__initcall(kallsyms_init);
	453
	454	EXPORT_SYMBOL(__print_symbol);