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Dynamic debug: allow simple quoting of words

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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: Greg Banks <gnb@melbourne.sgi.com>
Acked-by: Jason Baron <jbaron@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Greg Banks 2009-02-06 12:54:26 +11:00 committed by Greg Kroah-Hartman
parent 86151fdf38
commit 9898abb3d2
2 changed files with 47 additions and 26 deletions
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20
Documentation/dynamic-debug-howto.txt
View file

@ -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

53
lib/dynamic_debug.c
View file

@ -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)
return -EINVAL; /* ran out of words[] before bytes */
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;