Re: [PATCH v2 1/2] perf tools: Make find_vdso_map() more modular

Jiri Olsa
2018-11-27T09:33:41Z

On Thu, Oct 25, 2018 at 10:55:07AM -0700, Florian Fainelli wrote:
> In preparation for checking that the vectors page on the ARM
> architecture, refactor the find_vdso_map() function to accept finding an
> arbitrary string and create a dedicated helper function for that under
> util/find-map.c and update find_vdso_map() to use it.
>
> Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
> ---
> tools/perf/util/find-map.c | 31 +++++++++++++++++++++++++++++++
> tools/perf/util/find-vdso-map.c | 30 +++---------------------------
> 2 files changed, 34 insertions(+), 27 deletions(-)
> create mode 100644 tools/perf/util/find-map.c
>
> diff --git a/tools/perf/util/find-map.c b/tools/perf/util/find-map.c
> new file mode 100644
> index 000000000000..19a3431a7b2a
> --- /dev/null
> +++ b/tools/perf/util/find-map.c
> @@ -0,0 +1,31 @@
> +// SPDX-License-Identifier: GPL-2.0
> +static int find_map(void **start, void **end, const char *name)
> +{
> + FILE *maps;
> + char line[128];
> + int found = 0;
> +
> + maps = fopen("/proc/self/maps", "r");
> + if (!maps) {
> + fprintf(stderr, "vdso: cannot open maps\n");
> + return -1;
> + }
> +
> + while (!found && fgets(line, sizeof(line), maps)) {
> + int m = -1;
> +
> + /* We care only about private r-x mappings. */
> + if (2 != sscanf(line, "%p-%p r-xp %*x %*x:%*x %*u %n",
> + start, end, &m))
> + continue;
> + if (m < 0)
> + continue;
> +
> + if (!strncmp(&line[m], name, strlen(name)))
> + found = 1;
> + }
> +
> + fclose(maps);
> + return !found;
> +}
> +
> diff --git a/tools/perf/util/find-vdso-map.c b/tools/perf/util/find-vdso-map.c
> index d7823e3508fc..840d7d6e29e2 100644
> --- a/tools/perf/util/find-vdso-map.c
> +++ b/tools/perf/util/find-vdso-map.c
> @@ -1,31 +1,7 @@
> // SPDX-License-Identifier: GPL-2.0
> +#include "find-map.c"

aaah, I was wondering how this could build without 'Build' file record ;-)

jirka

> +
> static int find_vdso_map(void **start, void **end)
> {
> - FILE *maps;
> - char line[128];
> - int found = 0;
> -
> - maps = fopen("/proc/self/maps", "r");
> - if (!maps) {
> - fprintf(stderr, "vdso: cannot open maps\n");
> - return -1;
> - }
> -
> - while (!found && fgets(line, sizeof(line), maps)) {
> - int m = -1;
> -
> - /* We care only about private r-x mappings. */
> - if (2 != sscanf(line, "%p-%p r-xp %*x %*x:%*x %*u %n",
> - start, end, &m))
> - continue;
> - if (m < 0)
> - continue;
> -
> - if (!strncmp(&line[m], VDSO__MAP_NAME,
> - sizeof(VDSO__MAP_NAME) - 1))
> - found = 1;
> - }
> -
> - fclose(maps);
> - return !found;
> + return find_map(start, end, VDSO__MAP_NAME);
> }
> --
> 2.17.1
>