Commit 9898abb3 authored by Greg Banks's avatar Greg Banks Committed by Greg Kroah-Hartman
Browse files

Dynamic debug: allow simple quoting of words 



Allow simple quoting of words in the dynamic debug control language.

This allows more natural specification when using the control language
to match against printk formats, e.g

#echo -n 'format "Setting node for non-present cpu" +p' >
	/mnt/debugfs/dynamic_debug/control

instead of

#echo -n 'format Setting\040node\040for\040non-present\040cpu +p' >
	/mnt/debugfs/dynamic_debug/control

Adjust the dynamic debug documention to describe that and provide a
new example.  Adjust the existing examples in the documentation to
reflect the current whitespace escaping behaviour when reading the
control file.  Fix some minor documentation trailing whitespace.

Signed-off-by: default avatarGreg Banks <gnb@melbourne.sgi.com>
Acked-by: default avatarJason Baron <jbaron@redhat.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent 86151fdf

Documentation/dynamic-debug-howto.txt

+14 −6
Original line number Diff line number Diff line
@@ -49,10 +49,10 @@ via: 


nullarbor:~ # cat <debugfs>/dynamic_debug/control

# filename:lineno [module]function flags format

/usr/src/packages/BUILD/sgi-enhancednfs-1.4/default/net/sunrpc/svc_rdma.c:323 [svcxprt_rdma]svc_rdma_cleanup - "SVCRDMA\040Module\040Removed,\040deregister\040RPC\040RDMA\040transport\012"

/usr/src/packages/BUILD/sgi-enhancednfs-1.4/default/net/sunrpc/svc_rdma.c:341 [svcxprt_rdma]svc_rdma_init - "\011max_inline\040\040\040\040\040\040\040:\040%d\012"

/usr/src/packages/BUILD/sgi-enhancednfs-1.4/default/net/sunrpc/svc_rdma.c:340 [svcxprt_rdma]svc_rdma_init - "\011sq_depth\040\040\040\040\040\040\040\040\040:\040%d\012"

/usr/src/packages/BUILD/sgi-enhancednfs-1.4/default/net/sunrpc/svc_rdma.c:338 [svcxprt_rdma]svc_rdma_init - "\011max_requests\040\040\040\040\040:\040%d\012"

/usr/src/packages/BUILD/sgi-enhancednfs-1.4/default/net/sunrpc/svc_rdma.c:323 [svcxprt_rdma]svc_rdma_cleanup - "SVCRDMA Module Removed, deregister RPC RDMA transport\012"

/usr/src/packages/BUILD/sgi-enhancednfs-1.4/default/net/sunrpc/svc_rdma.c:341 [svcxprt_rdma]svc_rdma_init - "\011max_inline       : %d\012"

/usr/src/packages/BUILD/sgi-enhancednfs-1.4/default/net/sunrpc/svc_rdma.c:340 [svcxprt_rdma]svc_rdma_init - "\011sq_depth         : %d\012"

/usr/src/packages/BUILD/sgi-enhancednfs-1.4/default/net/sunrpc/svc_rdma.c:338 [svcxprt_rdma]svc_rdma_init - "\011max_requests     : %d\012"

...
@@ -72,7 +72,7 @@ you can view all the debug statement callsites with any non-default flags: 


nullarbor:~ # awk '$3 != "-"' <debugfs>/dynamic_debug/control

# filename:lineno [module]function flags format

/usr/src/packages/BUILD/sgi-enhancednfs-1.4/default/net/sunrpc/svcsock.c:1603 [sunrpc]svc_send p "svc_process:\040st_sendto\040returned\040%d\012"

/usr/src/packages/BUILD/sgi-enhancednfs-1.4/default/net/sunrpc/svcsock.c:1603 [sunrpc]svc_send p "svc_process: st_sendto returned %d\012"





Command Language Reference
@@ -166,11 +166,15 @@ format 
    entire format, only some part.  Whitespace and other

    special characters can be escaped using C octal character

    escape \ooo notation, e.g. the space character is \040.

    Alternatively, the string can be enclosed in double quote

    characters (") or single quote characters (').

    Examples:



    format svcrdma:	    // many of the NFS/RDMA server dprintks

    format readahead	    // some dprintks in the readahead cache

    format nfsd:\040SETATTR // how to match a format with whitespace

    format nfsd:\040SETATTR // one way to match a format with whitespace

    format "nfsd: SETATTR"  // a neater way to match a format with whitespace

    format 'nfsd: SETATTR'  // yet another way to match a format with whitespace



line

    The given line number or range of line numbers is compared
@@ -230,3 +234,7 @@ nullarbor:~ # echo -n 'func svc_process +p' > 
// disable all 12 messages in the function svc_process()

nullarbor:~ # echo -n 'func svc_process -p' >

				<debugfs>/dynamic_debug/control



// enable messages for NFS calls READ, READLINK, READDIR and READDIR+.

nullarbor:~ # echo -n 'format "nfsd: READ" +p' >

				<debugfs>/dynamic_debug/control

lib/dynamic_debug.c

+33 −20
Original line number Diff line number Diff line
@@ -195,33 +195,46 @@ static void ddebug_change(const struct ddebug_query *query, 
		printk(KERN_INFO "ddebug: no matches for query\n");

}



/*

 * Wrapper around strsep() to collapse the multiple empty tokens

 * that it returns when fed sequences of separator characters.

 * Now, if we had strtok_r()...

 */

static inline char *nearly_strtok_r(char **p, const char *sep)

{

	char *r;



	while ((r = strsep(p, sep)) != NULL && *r == '\0')

		;

	return r;

}



/*

 * Split the buffer `buf' into space-separated words.

 * Return the number of such words or <0 on error.

 * 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 (nwords < maxwords &&

	       (words[nwords] = nearly_strtok_r(&buf, " \t\r\n")) != NULL)

		nwords++;

	if (buf)

	while (*buf) {

		char *end;



		/* Skip leading whitespace */

		while (*buf && isspace(*buf))

			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;

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