Re: [PATCH v2 1/1] perf tools: remove sscanf extension %as

From: Masami Hiramatsu
Date: Mon Sep 24 2012 - 03:13:34 EST


(2012/09/21 5:37), irina.tirdea@xxxxxxxxx wrote:
> From: Irina Tirdea <irina.tirdea@xxxxxxxxx>
>
> perf uses sscanf extension %as to read and allocate a
> string in the same step. This is a non-standard extension
> only present in new versions of glibc.
>
> Replacing the use of sscanf and %as with strtok_r calls
> in order to parse a given string into its components.
> This is needed in Android since bionic does not support
> %as extension for sscanf.

OK, I've reviewed and tested, looks good! :)

Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@xxxxxxxxxxx>

Thank you!

>
> Signed-off-by: Irina Tirdea <irina.tirdea@xxxxxxxxx>
> ---
> tools/perf/util/probe-event.c | 36 ++++++++++++++++++++++++++++-------
> tools/perf/util/trace-event-parse.c | 18 ++++++++----------
> 2 files changed, 37 insertions(+), 17 deletions(-)
>
> diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
> index 4ce04c2..49a256e 100644
> --- a/tools/perf/util/probe-event.c
> +++ b/tools/perf/util/probe-event.c
> @@ -1100,6 +1100,7 @@ static int parse_probe_trace_command(const char *cmd,
> struct probe_trace_point *tp = &tev->point;
> char pr;
> char *p;
> + char *argv0_str = NULL, *fmt, *fmt1_str, *fmt2_str, *fmt3_str;
> int ret, i, argc;
> char **argv;
>
> @@ -1116,14 +1117,27 @@ static int parse_probe_trace_command(const char *cmd,
> }
>
> /* Scan event and group name. */
> - ret = sscanf(argv[0], "%c:%a[^/ \t]/%a[^ \t]",
> - &pr, (float *)(void *)&tev->group,
> - (float *)(void *)&tev->event);
> - if (ret != 3) {
> + argv0_str = strdup(argv[0]);
> + if (argv0_str == NULL) {
> + ret = -ENOMEM;
> + goto out;
> + }
> + fmt1_str = strtok_r(argv0_str, ":", &fmt);
> + fmt2_str = strtok_r(NULL, "/", &fmt);
> + fmt3_str = strtok_r(NULL, " \t", &fmt);
> + if (fmt1_str == NULL || strlen(fmt1_str) != 1 || fmt2_str == NULL
> + || fmt3_str == NULL) {
> semantic_error("Failed to parse event name: %s\n", argv[0]);
> ret = -EINVAL;
> goto out;
> }
> + pr = fmt1_str[0];
> + tev->group = strdup(fmt2_str);
> + tev->event = strdup(fmt3_str);
> + if (tev->group == NULL || tev->event == NULL) {
> + ret = -ENOMEM;
> + goto out;
> + }
> pr_debug("Group:%s Event:%s probe:%c\n", tev->group, tev->event, pr);
>
> tp->retprobe = (pr == 'r');
> @@ -1135,10 +1149,17 @@ static int parse_probe_trace_command(const char *cmd,
> p++;
> } else
> p = argv[1];
> - ret = sscanf(p, "%a[^+]+%lu", (float *)(void *)&tp->symbol,
> - &tp->offset);
> - if (ret == 1)
> + fmt1_str = strtok_r(p, "+", &fmt);
> + tp->symbol = strdup(fmt1_str);
> + if (tp->symbol == NULL) {
> + ret = -ENOMEM;
> + goto out;
> + }
> + fmt2_str = strtok_r(NULL, "", &fmt);
> + if (fmt2_str == NULL)
> tp->offset = 0;
> + else
> + tp->offset = strtoul(fmt2_str, NULL, 10);
>
> tev->nargs = argc - 2;
> tev->args = zalloc(sizeof(struct probe_trace_arg) * tev->nargs);
> @@ -1162,6 +1183,7 @@ static int parse_probe_trace_command(const char *cmd,
> }
> ret = 0;
> out:
> + free(argv0_str);
> argv_free(argv);
> return ret;
> }
> diff --git a/tools/perf/util/trace-event-parse.c b/tools/perf/util/trace-event-parse.c
> index aa4c860..3aabcd6 100644
> --- a/tools/perf/util/trace-event-parse.c
> +++ b/tools/perf/util/trace-event-parse.c
> @@ -229,24 +229,22 @@ void parse_proc_kallsyms(struct pevent *pevent,
> char *next = NULL;
> char *addr_str;
> char *mod;
> - char ch;
> + char *fmt;
>
> line = strtok_r(file, "\n", &next);
> while (line) {
> mod = NULL;
> - sscanf(line, "%as %c %as\t[%as",
> - (float *)(void *)&addr_str, /* workaround gcc warning */
> - &ch, (float *)(void *)&func, (float *)(void *)&mod);
> + addr_str = strtok_r(line, " ", &fmt);
> addr = strtoull(addr_str, NULL, 16);
> - free(addr_str);
> -
> - /* truncate the extra ']' */
> + /* skip character */
> + strtok_r(NULL, " ", &fmt);
> + func = strtok_r(NULL, "\t", &fmt);
> + mod = strtok_r(NULL, "]", &fmt);
> + /* truncate the extra '[' */
> if (mod)
> - mod[strlen(mod) - 1] = 0;
> + mod = mod + 1;
>
> pevent_register_function(pevent, func, addr, mod);
> - free(func);
> - free(mod);
>
> line = strtok_r(NULL, "\n", &next);
> }
>


--
Masami HIRAMATSU
Software Platform Research Dept. Linux Technology Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: masami.hiramatsu.pt@xxxxxxxxxxx


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