[PATCH 15/25] dynamic_debug: add trim_prefix() to provide source-root relative paths

From: jim . cromie
Date: Mon Dec 12 2011 - 18:13:38 EST


From: Jim Cromie <jim.cromie@xxxxxxxxx>

trim_prefix(path) skips past the absolute source path root, and
returns the pointer to the relative path from there. It is used to
shorten the displayed path in $DBGMT/dynamic_debug/control via
ddebug_proc_show(), and in ddebug_change() to allow relative filenames
to be used in applied queries. For example:

~# echo file kernel/freezer.c +p > $DBGMT/dynamic_debug/control

kernel/freezer.c:128 [freezer]cancel_freezing p " clean up: %s\012"

trim_prefix(path) insures common prefix before trimming it, so
out-of-tree module paths are shown as full absolute paths.

Signed-off-by: Jim Cromie <jim.cromie@xxxxxxxxx>
---
Documentation/dynamic-debug-howto.txt | 7 ++++---
lib/dynamic_debug.c | 18 +++++++++++++++---
2 files changed, 19 insertions(+), 6 deletions(-)

diff --git a/Documentation/dynamic-debug-howto.txt b/Documentation/dynamic-debug-howto.txt
index f959909..378b5d1 100644
--- a/Documentation/dynamic-debug-howto.txt
+++ b/Documentation/dynamic-debug-howto.txt
@@ -144,11 +144,12 @@ func
func svc_tcp_accept

file
- The given string is compared against either the full
- pathname or the basename of the source file of each
- callsite. Examples:
+ The given string is compared against either the full pathname, the
+ src-root relative pathname, or the basename of the source file of
+ each callsite. Examples:

file svcsock.c
+ file kernel/freezer.c
file /usr/src/packages/BUILD/sgi-enhancednfs-1.4/default/net/sunrpc/svcsock.c

module
diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index 6e5b9a3..cb078d4 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -69,6 +69,17 @@ static inline const char *basename(const char *path)
return tail ? tail+1 : path;
}

+/* Return the path relative to source root */
+static inline const char *trim_prefix(const char *path)
+{
+ int skip = strlen(__FILE__) - strlen("lib/dynamic_debug.c");
+
+ if (strncmp(path, __FILE__, skip))
+ skip = 0; /* prefix mismatch, don't skip */
+
+ return path + skip;
+}
+
static struct { unsigned flag:8; char opt_char; } opt_array[] = {
{ _DPRINTK_FLAGS_PRINT, 'p' },
{ _DPRINTK_FLAGS_INCL_MODNAME, 'm' },
@@ -125,7 +136,8 @@ static void ddebug_change(const struct ddebug_query *query,
/* match against the source filename */
if (query->filename &&
strcmp(query->filename, dp->filename) &&
- strcmp(query->filename, basename(dp->filename)))
+ strcmp(query->filename, basename(dp->filename)) &&
+ strcmp(query->filename, trim_prefix(dp->filename)))
continue;

/* match against the function */
@@ -154,7 +166,7 @@ static void ddebug_change(const struct ddebug_query *query,
dp->flags = newflags;
if (verbose)
pr_info("changed %s:%d [%s]%s =%s\n",
- dp->filename, dp->lineno,
+ trim_prefix(dp->filename), dp->lineno,
dt->mod_name, dp->function,
ddebug_describe_flags(dp, flagbuf,
sizeof(flagbuf)));
@@ -714,7 +726,7 @@ static int ddebug_proc_show(struct seq_file *m, void *p)
}

seq_printf(m, "%s:%u [%s]%s =%s \"",
- dp->filename, dp->lineno,
+ trim_prefix(dp->filename), dp->lineno,
iter->table->mod_name, dp->function,
ddebug_describe_flags(dp, flagsbuf, sizeof(flagsbuf)));
seq_escape(m, dp->format, "\t\r\n\"");
--
1.7.7.3

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/