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

From: Florian Fainelli
Date: Wed Oct 24 2018 - 20:14:33 EST


On 10/24/18 5:09 PM, 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@xxxxxxxxx>
> ---
> 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..42533fc21108
> --- /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, sizeof(name) - 1))

Meh, this should be strlen() now, but I would like to hear comments
before submitting a v2 of this anyway. Thanks!
--
Florian