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/* * lib/dynamic_debug.c * * make pr_debug()/dev_dbg() calls runtime configurable based upon their * source module. * * Copyright (C) 2008 Jason Baron <jbaron@redhat.com> * By Greg Banks <gnb@melbourne.sgi.com> * Copyright (c) 2008 Silicon Graphics Inc.  All Rights Reserved. * Copyright (C) 2011 Bart Van Assche.  All Rights Reserved. */ #define pr_fmt(fmt) KBUILD_MODNAME ":%s: " fmt, __func__ #include <linux/kernel.h>#include <linux/module.h>#include <linux/moduleparam.h>#include <linux/kallsyms.h>#include <linux/types.h>#include <linux/mutex.h>#include <linux/proc_fs.h>#include <linux/seq_file.h>#include <linux/list.h>#include <linux/sysctl.h>#include <linux/ctype.h>#include <linux/string.h>#include <linux/uaccess.h>#include <linux/dynamic_debug.h>#include <linux/debugfs.h>#include <linux/slab.h>#include <linux/jump_label.h>#include <linux/hardirq.h>#include <linux/sched.h>#include <linux/device.h>#include <linux/netdevice.h> extern struct _ddebug __start___verbose[];extern struct _ddebug __stop___verbose[]; struct ddebug_table {	struct list_head link;	char *mod_name;	unsigned int num_ddebugs;	struct _ddebug *ddebugs;}; struct ddebug_query {	const char *filename;	const char *module;	const char *function;	const char *format;	unsigned int first_lineno, last_lineno;}; struct ddebug_iter {	struct ddebug_table *table;	unsigned int idx;}; static DEFINE_MUTEX(ddebug_lock);static LIST_HEAD(ddebug_tables);static int verbose = 0; /* Return the last part of a pathname */static inline const char *basename(const char *path){	const char *tail = strrchr(path, '/');	return tail ? tail+1 : path;} static struct { unsigned flag:8; char opt_char; } opt_array[] = {	{ _DPRINTK_FLAGS_PRINT, 'p' },	{ _DPRINTK_FLAGS_INCL_MODNAME, 'm' },	{ _DPRINTK_FLAGS_INCL_FUNCNAME, 'f' },	{ _DPRINTK_FLAGS_INCL_LINENO, 'l' },	{ _DPRINTK_FLAGS_INCL_TID, 't' },}; /* format a string into buf[] which describes the _ddebug's flags */static char *ddebug_describe_flags(struct _ddebug *dp, char *buf,				    size_t maxlen){	char *p = buf;	int i; 	BUG_ON(maxlen < 4);	for (i = 0; i < ARRAY_SIZE(opt_array); ++i)		if (dp->flags & opt_array[i].flag)			*p++ = opt_array[i].opt_char;	if (p == buf)		*p++ = '-';	*p = '\0'; 	return buf;} /* * Search the tables for _ddebug's which match the given * `query' and apply the `flags' and `mask' to them.  Tells * the user which ddebug's were changed, or whether none * were matched. */static void ddebug_change(const struct ddebug_query *query,			   unsigned int flags, unsigned int mask){	int i;	struct ddebug_table *dt;	unsigned int newflags;	unsigned int nfound = 0;	char flagbuf[8]; 	/* search for matching ddebugs */	mutex_lock(&ddebug_lock);	list_for_each_entry(dt, &ddebug_tables, link) { 		/* match against the module name */		if (query->module != NULL &&		    strcmp(query->module, dt->mod_name))			continue; 		for (i = 0 ; i < dt->num_ddebugs ; i++) {			struct _ddebug *dp = &dt->ddebugs[i]; 			/* match against the source filename */			if (query->filename != NULL &&			    strcmp(query->filename, dp->filename) &&			    strcmp(query->filename, basename(dp->filename)))				continue; 			/* match against the function */			if (query->function != NULL &&			    strcmp(query->function, dp->function))				continue; 			/* match against the format */			if (query->format != NULL &&			    strstr(dp->format, query->format) == NULL)				continue; 			/* match against the line number range */			if (query->first_lineno &&			    dp->lineno < query->first_lineno)				continue;			if (query->last_lineno &&			    dp->lineno > query->last_lineno)				continue; 			nfound++; 			newflags = (dp->flags & mask) | flags;			if (newflags == dp->flags)				continue;			dp->flags = newflags;			if (newflags)				dp->enabled = 1;			else				dp->enabled = 0;			if (verbose)				pr_info("changed %s:%d [%s]%s %s\n",					dp->filename, dp->lineno,					dt->mod_name, dp->function,					ddebug_describe_flags(dp, flagbuf,							sizeof(flagbuf)));		}	}	mutex_unlock(&ddebug_lock); 	if (!nfound && verbose)		pr_info("no matches for query\n");} /* * Split the buffer `buf' into space-separated words. * Handles simple " and ' quoting, i.e. without nested, * embedded or escaped \".  Return the number of words * or <0 on error. */static int ddebug_tokenize(char *buf, char *words[], int maxwords){	int nwords = 0; 	while (*buf) {		char *end; 		/* Skip leading whitespace */		buf = skip_spaces(buf);		if (!*buf)			break;	/* oh, it was trailing whitespace */ 		/* Run `end' over a word, either whitespace separated or quoted */		if (*buf == '"' || *buf == '\'') {			int quote = *buf++;			for (end = buf ; *end && *end != quote ; end++)				;			if (!*end)				return -EINVAL;	/* unclosed quote */		} else {			for (end = buf ; *end && !isspace(*end) ; end++)				;			BUG_ON(end == buf);		}		/* Here `buf' is the start of the word, `end' is one past the end */ 		if (nwords == maxwords)			return -EINVAL;	/* ran out of words[] before bytes */		if (*end)			*end++ = '\0';	/* terminate the word */		words[nwords++] = buf;		buf = end;	} 	if (verbose) {		int i;		pr_info("split into words:");		for (i = 0 ; i < nwords ; i++)			pr_cont(" \"%s\"", words[i]);		pr_cont("\n");	} 	return nwords;} /* * Parse a single line number.  Note that the empty string "" * is treated as a special case and converted to zero, which * is later treated as a "don't care" value. */static inline int parse_lineno(const char *str, unsigned int *val){	char *end = NULL;	BUG_ON(str == NULL);	if (*str == '\0') {		*val = 0;		return 0;	}	*val = simple_strtoul(str, &end, 10);	return end == NULL || end == str || *end != '\0' ? -EINVAL : 0;} /* * Undo octal escaping in a string, inplace.  This is useful to * allow the user to express a query which matches a format * containing embedded spaces. */#define isodigit(c)		((c) >= '0' && (c) <= '7')static char *unescape(char *str){	char *in = str;	char *out = str; 	while (*in) {		if (*in == '\\') {			if (in[1] == '\\') {				*out++ = '\\';				in += 2;				continue;			} else if (in[1] == 't') {				*out++ = '\t';				in += 2;				continue;			} else if (in[1] == 'n') {				*out++ = '\n';				in += 2;				continue;			} else if (isodigit(in[1]) &&			         isodigit(in[2]) &&			         isodigit(in[3])) {				*out++ = ((in[1] - '0')<<6) |				          ((in[2] - '0')<<3) |				          (in[3] - '0');				in += 4;				continue;			}		}		*out++ = *in++;	}	*out = '\0'; 	return str;} /* * Parse words[] as a ddebug query specification, which is a series * of (keyword, value) pairs chosen from these possibilities: * * func <function-name> * file <full-pathname> * file <base-filename> * module <module-name> * format <escaped-string-to-find-in-format> * line <lineno> * line <first-lineno>-<last-lineno> // where either may be empty */static int ddebug_parse_query(char *words[], int nwords,			       struct ddebug_query *query){	unsigned int i; 	/* check we have an even number of words */	if (nwords % 2 != 0)		return -EINVAL;	memset(query, 0, sizeof(*query)); 	for (i = 0 ; i < nwords ; i += 2) {		if (!strcmp(words[i], "func"))			query->function = words[i+1];		else if (!strcmp(words[i], "file"))			query->filename = words[i+1];		else if (!strcmp(words[i], "module"))			query->module = words[i+1];		else if (!strcmp(words[i], "format"))			query->format = unescape(words[i+1]);		else if (!strcmp(words[i], "line")) {			char *first = words[i+1];			char *last = strchr(first, '-');			if (last)				*last++ = '\0';			if (parse_lineno(first, &query->first_lineno) < 0)				return -EINVAL;			if (last != NULL) {				/* range <first>-<last> */				if (parse_lineno(last, &query->last_lineno) < 0)					return -EINVAL;			} else {				query->last_lineno = query->first_lineno;			}		} else {			if (verbose)				pr_err("unknown keyword \"%s\"\n", words[i]);			return -EINVAL;		}	} 	if (verbose)		pr_info("q->function=\"%s\" q->filename=\"%s\" "			"q->module=\"%s\" q->format=\"%s\" q->lineno=%u-%u\n",			query->function, query->filename,			query->module, query->format, query->first_lineno,			query->last_lineno); 	return 0;} /* * Parse `str' as a flags specification, format [-+=][p]+. * Sets up *maskp and *flagsp to be used when changing the * flags fields of matched _ddebug's.  Returns 0 on success * or <0 on error. */static int ddebug_parse_flags(const char *str, unsigned int *flagsp,			       unsigned int *maskp){	unsigned flags = 0;	int op = '=', i; 	switch (*str) {	case '+':	case '-':	case '=':		op = *str++;		break;	default:		return -EINVAL;	}	if (verbose)		pr_info("op='%c'\n", op); 	for ( ; *str ; ++str) {		for (i = ARRAY_SIZE(opt_array) - 1; i >= 0; i--) {			if (*str == opt_array[i].opt_char) {				flags |= opt_array[i].flag;				break;			}		}		if (i < 0)			return -EINVAL;	}	if (flags == 0)		return -EINVAL;	if (verbose)		pr_info("flags=0x%x\n", flags); 	/* calculate final *flagsp, *maskp according to mask and op */	switch (op) {	case '=':		*maskp = 0;		*flagsp = flags;		break;	case '+':		*maskp = ~0U;		*flagsp = flags;		break;	case '-':		*maskp = ~flags;		*flagsp = 0;		break;	}	if (verbose)		pr_info("*flagsp=0x%x *maskp=0x%x\n", *flagsp, *maskp);	return 0;} static int ddebug_exec_query(char *query_string){	unsigned int flags = 0, mask = 0;	struct ddebug_query query;#define MAXWORDS 9	int nwords;	char *words[MAXWORDS]; 	nwords = ddebug_tokenize(query_string, words, MAXWORDS);	if (nwords <= 0)		return -EINVAL;	if (ddebug_parse_query(words, nwords-1, &query))		return -EINVAL;	if (ddebug_parse_flags(words[nwords-1], &flags, &mask))		return -EINVAL; 	/* actually go and implement the change */	ddebug_change(&query, flags, mask);	return 0;} #define PREFIX_SIZE 64 static int remaining(int wrote){	if (PREFIX_SIZE - wrote > 0)		return PREFIX_SIZE - wrote;	return 0;} static char *dynamic_emit_prefix(const struct _ddebug *desc, char *buf){	int pos_after_tid;	int pos = 0; 	pos += snprintf(buf + pos, remaining(pos), "%s", KERN_DEBUG);	if (desc->flags & _DPRINTK_FLAGS_INCL_TID) {		if (in_interrupt())			pos += snprintf(buf + pos, remaining(pos), "%s ",						"<intr>");		else			pos += snprintf(buf + pos, remaining(pos), "[%d] ",						task_pid_vnr(current));	}	pos_after_tid = pos;	if (desc->flags & _DPRINTK_FLAGS_INCL_MODNAME)		pos += snprintf(buf + pos, remaining(pos), "%s:",					desc->modname);	if (desc->flags & _DPRINTK_FLAGS_INCL_FUNCNAME)		pos += snprintf(buf + pos, remaining(pos), "%s:",					desc->function);	if (desc->flags & _DPRINTK_FLAGS_INCL_LINENO)		pos += snprintf(buf + pos, remaining(pos), "%d:", desc->lineno);	if (pos - pos_after_tid)		pos += snprintf(buf + pos, remaining(pos), " ");	if (pos >= PREFIX_SIZE)		buf[PREFIX_SIZE - 1] = '\0'; 	return buf;} int __dynamic_pr_debug(struct _ddebug *descriptor, const char *fmt, ...){	va_list args;	int res;	struct va_format vaf;	char buf[PREFIX_SIZE]; 	BUG_ON(!descriptor);	BUG_ON(!fmt); 	va_start(args, fmt);	vaf.fmt = fmt;	vaf.va = &args;	res = printk("%s%pV", dynamic_emit_prefix(descriptor, buf), &vaf);	va_end(args); 	return res;}EXPORT_SYMBOL(__dynamic_pr_debug); int __dynamic_dev_dbg(struct _ddebug *descriptor,		      const struct device *dev, const char *fmt, ...){	struct va_format vaf;	va_list args;	int res;	char buf[PREFIX_SIZE]; 	BUG_ON(!descriptor);	BUG_ON(!fmt); 	va_start(args, fmt);	vaf.fmt = fmt;	vaf.va = &args;	res = __dev_printk(dynamic_emit_prefix(descriptor, buf), dev, &vaf);	va_end(args); 

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