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Date: Thu, 15 Jul 2010 14:13:13 -0300
From: Arnaldo Carvalho de Melo <acme@...hat.com>
To: Masami Hiramatsu <masami.hiramatsu.pt@...achi.com>
Cc: Chase Douglas <chase.douglas@...onical.com>,
linux-kernel@...r.kernel.org, Ingo Molnar <mingo@...e.hu>
Subject: Re: [PATCH 1/3] perf probe: Fix error message if get_real_path()
failed
Em Fri, Jul 16, 2010 at 01:38:59AM +0900, Masami Hiramatsu escreveu:
> Hi Arnaldo,
>
> Could you please merge this series, because this series
> fixes some bugs which people easily hit ?
I'll take a look at it, thanks for pointing it out.
- Arnaldo
> Thank you,
>
> Chase Douglas wrote:
> > On Fri, 2010-07-09 at 18:28 +0900, Masami Hiramatsu wrote:
> >> Perf probe -L shows incorrect error message (Dwarf error)
> >> if it fails to find source file. This can confuse users.
> >>
> >> # ./perf probe -s /nowhere -L vfs_read
> >> Debuginfo analysis failed. (-2)
> >> Error: Failed to show lines. (-2)
> >>
> >> With this patch, it shows correct message.
> >>
> >> # ./perf probe -s /nowhere -L vfs_read
> >> Failed to find source file. (-2)
> >> Error: Failed to show lines. (-2)
> >>
> >> Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@...achi.com>
> >> Cc: Chase Douglas <chase.douglas@...onical.com>
> >> Cc: Arnaldo Carvalho de Melo <acme@...hat.com>
> >> Cc: Ingo Molnar <mingo@...e.hu>
> >> ---
> >>
> >> tools/perf/util/probe-event.c | 59 +++++++++++++++++++++++++++++++++++++++
> >> tools/perf/util/probe-finder.c | 61 +++-------------------------------------
> >> 2 files changed, 64 insertions(+), 56 deletions(-)
> >>
> >> diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
> >> index 09cf546..8d08e75 100644
> >> --- a/tools/perf/util/probe-event.c
> >> +++ b/tools/perf/util/probe-event.c
> >> @@ -195,6 +195,55 @@ static int try_to_find_kprobe_trace_events(struct perf_probe_event *pev,
> >> return ntevs;
> >> }
> >>
> >> +/*
> >> + * Find a src file from a DWARF tag path. Prepend optional source path prefix
> >> + * and chop off leading directories that do not exist. Result is passed back as
> >> + * a newly allocated path on success.
> >> + * Return 0 if file was found and readable, -errno otherwise.
> >> + */
> >> +static int get_real_path(const char *raw_path, char **new_path)
> >> +{
> >> + if (!symbol_conf.source_prefix) {
> >> + if (access(raw_path, R_OK) == 0) {
> >> + *new_path = strdup(raw_path);
> >> + return 0;
> >> + } else
> >> + return -errno;
> >> + }
> >> +
> >> + *new_path = malloc((strlen(symbol_conf.source_prefix) +
> >> + strlen(raw_path) + 2));
> >> + if (!*new_path)
> >> + return -ENOMEM;
> >> +
> >> + for (;;) {
> >> + sprintf(*new_path, "%s/%s", symbol_conf.source_prefix,
> >> + raw_path);
> >> +
> >> + if (access(*new_path, R_OK) == 0)
> >> + return 0;
> >> +
> >> + switch (errno) {
> >> + case ENAMETOOLONG:
> >> + case ENOENT:
> >> + case EROFS:
> >> + case EFAULT:
> >> + raw_path = strchr(++raw_path, '/');
> >> + if (!raw_path) {
> >> + free(*new_path);
> >> + *new_path = NULL;
> >> + return -ENOENT;
> >> + }
> >> + continue;
> >> +
> >> + default:
> >> + free(*new_path);
> >> + *new_path = NULL;
> >> + return -errno;
> >> + }
> >> + }
> >> +}
> >> +
> >> #define LINEBUF_SIZE 256
> >> #define NR_ADDITIONAL_LINES 2
> >>
> >> @@ -244,6 +293,7 @@ int show_line_range(struct line_range *lr)
> >> struct line_node *ln;
> >> FILE *fp;
> >> int fd, ret;
> >> + char *tmp;
> >>
> >> /* Search a line range */
> >> ret = init_vmlinux();
> >> @@ -266,6 +316,15 @@ int show_line_range(struct line_range *lr)
> >> return ret;
> >> }
> >>
> >> + /* Convert source file path */
> >> + tmp = lr->path;
> >> + ret = get_real_path(tmp, &lr->path);
> >> + free(tmp); /* Free old path */
> >> + if (ret < 0) {
> >> + pr_warning("Failed to find source file. (%d)\n", ret);
> >> + return ret;
> >> + }
> >> +
> >> setup_pager();
> >>
> >> if (lr->function)
> >> diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c
> >> index 3e64e1f..a934a36 100644
> >> --- a/tools/perf/util/probe-finder.c
> >> +++ b/tools/perf/util/probe-finder.c
> >> @@ -58,55 +58,6 @@ static int strtailcmp(const char *s1, const char *s2)
> >> return 0;
> >> }
> >>
> >> -/*
> >> - * Find a src file from a DWARF tag path. Prepend optional source path prefix
> >> - * and chop off leading directories that do not exist. Result is passed back as
> >> - * a newly allocated path on success.
> >> - * Return 0 if file was found and readable, -errno otherwise.
> >> - */
> >> -static int get_real_path(const char *raw_path, char **new_path)
> >> -{
> >> - if (!symbol_conf.source_prefix) {
> >> - if (access(raw_path, R_OK) == 0) {
> >> - *new_path = strdup(raw_path);
> >> - return 0;
> >> - } else
> >> - return -errno;
> >> - }
> >> -
> >> - *new_path = malloc((strlen(symbol_conf.source_prefix) +
> >> - strlen(raw_path) + 2));
> >> - if (!*new_path)
> >> - return -ENOMEM;
> >> -
> >> - for (;;) {
> >> - sprintf(*new_path, "%s/%s", symbol_conf.source_prefix,
> >> - raw_path);
> >> -
> >> - if (access(*new_path, R_OK) == 0)
> >> - return 0;
> >> -
> >> - switch (errno) {
> >> - case ENAMETOOLONG:
> >> - case ENOENT:
> >> - case EROFS:
> >> - case EFAULT:
> >> - raw_path = strchr(++raw_path, '/');
> >> - if (!raw_path) {
> >> - free(*new_path);
> >> - *new_path = NULL;
> >> - return -ENOENT;
> >> - }
> >> - continue;
> >> -
> >> - default:
> >> - free(*new_path);
> >> - *new_path = NULL;
> >> - return -errno;
> >> - }
> >> - }
> >> -}
> >> -
> >> /* Line number list operations */
> >>
> >> /* Add a line to line number list */
> >> @@ -1256,13 +1207,11 @@ end:
> >> static int line_range_add_line(const char *src, unsigned int lineno,
> >> struct line_range *lr)
> >> {
> >> - int ret;
> >> -
> >> - /* Copy real path */
> >> + /* Copy source path */
> >> if (!lr->path) {
> >> - ret = get_real_path(src, &lr->path);
> >> - if (ret != 0)
> >> - return ret;
> >> + lr->path = strdup(src);
> >> + if (lr->path == NULL)
> >> + return -ENOMEM;
> >> }
> >> return line_list__add_line(&lr->line_list, lineno);
> >> }
> >> @@ -1460,7 +1409,7 @@ int find_line_range(int fd, struct line_range *lr)
> >> }
> >> off = noff;
> >> }
> >> - pr_debug("path: %lx\n", (unsigned long)lr->path);
> >> + pr_debug("path: %s\n", lr->path);
> >> dwarf_end(dbg);
> >>
> >> return (ret < 0) ? ret : lf.found;
> >
> > This seems fine to me. I don't think any functionality has really
> > changed, just moving the function into probe-event.c and printing out an
> > accurate error message.
> >
> > Acked-by: Chase Douglas <chase.douglas@...onical.com>
> >
> > Thanks!
> >
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