perf tools: Asprintf like functions to format integer filter expression

tip:perf/core tip-bot for Arnaldo Carvalho de Melo 1 participant 1 message Jul 6, 2015 perf events

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2015-07-06 16:31 UTC #0 lore raw

Commit-ID:  93ec4ce789995c5c58dff82193b3ec77caa8aecb
Gitweb:     http://git.kernel.org/tip/93ec4ce789995c5c58dff82193b3ec77caa8aecb
Author:     Arnaldo Carvalho de Melo <[email protected]>
AuthorDate: Thu, 2 Jul 2015 17:48:23 -0300
Committer:  Arnaldo Carvalho de Melo <[email protected]>
CommitDate: Mon, 6 Jul 2015 10:21:46 -0300

perf tools: Asprintf like functions to format integer filter expression

  char *asprintf_expr_in_ints(const char *var, size_t nints, int *ints);
  char *asprintf_expr_not_in_ints(const char *var, size_t nints, int *ints);

Example of output formatted with those functions:

  # ./tp_filter 6 12 2015
  asprintf_expr_in_ints:     id == 6 || id == 12 || id == 2015
  asprintf_expr_not_in_ints: id != 6 && id != 12 && id != 2015
  #

It'll be used with, for instance, perf_evsel__set_filter_in_ints(), that will be used in turn to ask the kernel to filter out all raw_syscalls:* except for the ones specified by the user via:

 $ perf trace -e some,list,of,syscalls

Cc Adrian Hunter <[email protected]>

Cc Borislav Petkov <[email protected]>

Cc David Ahern <[email protected]>

Cc Don Zickus <[email protected]>

Cc Frederic Weisbecker <[email protected]>

Cc Jiri Olsa <[email protected]>

Cc Namhyung Kim <[email protected]>

Cc Stephane Eranian <[email protected]>

Link http://lkml.kernel.org/n/[email protected] open here

Signed-off-by Arnaldo Carvalho de Melo <[email protected]>

---
 tools/perf/util/string.c | 39 +++++++++++++++++++++++++++++++++++++++
 tools/perf/util/util.h   | 12 ++++++++++++
 2 files changed, 51 insertions(+)

tools/perf/util/string.c +39 -0

index 6afd610..fc8781d 100644
@@ -357,3 +357,42 @@ void *memdup(const void *src, size_t len)
 
 	return p;
 }
+
+char *asprintf_expr_inout_ints(const char *var, bool in, size_t nints, int *ints)
+{
+	/*
+	 * FIXME: replace this with an expression using log10() when we
+	 * find a suitable implementation, maybe the one in the dvb drivers...
+	 *
+	 * "%s == %d || " = log10(MAXINT) * 2 + 8 chars for the operators
+	 */
+	size_t size = nints * 28 + 1; /* \0 */
+	size_t i, printed = 0;
+	char *expr = malloc(size);
+
+	if (expr) {
+		const char *or_and = "||", *eq_neq = "==";
+		char *e = expr;
+
+		if (!in) {
+			or_and = "&&";
+			eq_neq = "!=";
+		}
+
+		for (i = 0; i < nints; ++i) {
+			if (printed == size)
+				goto out_err_overflow;
+
+			if (i > 0)
+				printed += snprintf(e + printed, size - printed, " %s ", or_and);
+			printed += scnprintf(e + printed, size - printed,
+					     "%s %s %d", var, eq_neq, ints[i]);
+		}
+	}
+
+	return expr;
+
+out_err_overflow:
+	free(expr);
+	return NULL;
+}

tools/perf/util/util.h +12 -0

index 8bce58b..20d625a 100644
@@ -339,4 +339,16 @@ int gzip_decompress_to_file(const char *input, int output_fd);
 int lzma_decompress_to_file(const char *input, int output_fd);
 #endif
 
+char *asprintf_expr_inout_ints(const char *var, bool in, size_t nints, int *ints);
+
+static inline char *asprintf_expr_in_ints(const char *var, size_t nints, int *ints)
+{
+	return asprintf_expr_inout_ints(var, true, nints, ints);
+}
+
+static inline char *asprintf_expr_not_in_ints(const char *var, size_t nints, int *ints)
+{
+	return asprintf_expr_inout_ints(var, false, nints, ints);
+}
+
 #endif /* GIT_COMPAT_UTIL_H */