perf report: Accept fifos as input file

The default input file for perf report is not handled the same way as
perf record does it for its output file. This leads to unexpected
behavior of perf report, etc. E.g.:

# perf record -a -e cpu-cycles sleep 2 | perf report | cat
failed to open perf.data: No such file or directory (try 'perf record' first)

While perf record writes to a fifo, perf report expects perf.data to be
read. This patch changes this to accept fifos as input file.

Applies to the following commands:

perf annotate
perf buildid-list
perf evlist
perf kmem
perf lock
perf report
perf sched
perf script
perf timechart

Also fixes char const* -> const char* type declaration for filename
strings.

v2:
* Prevent potential null pointer access to input_name in
builtin-report.c. Needed due to removal of patch "perf report: Setup
browser if stdout is a pipe"

Cc: Frederic Weisbecker <[e-mail]>
Cc: Ingo Molnar <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Cc: Stephane Eranian <[e-mail]>
Link: http://lkml.kernel.org/r/[e-mail]
Signed-off-by: Robert Richter <[e-mail]>
Signed-off-by: Arnaldo Carvalho de Melo <[e-mail]>

tools/perf/Documentation/perf-annotate.txt

···
 -------
 -i::
 --input=::
-        Input file name. (default: perf.data)
+        Input file name. (default: perf.data unless stdin is a fifo)
 
 -d::
 --dsos=<dso[,dso...]>::

tools/perf/Documentation/perf-buildid-list.txt

···
         Show only DSOs with hits.
 -i::
 --input=::
-        Input file name. (default: perf.data)
+        Input file name. (default: perf.data unless stdin is a fifo)
 -f::
 --force::
 	Don't do ownership validation.

tools/perf/Documentation/perf-evlist.txt

···
 -------
 -i::
 --input=::
-        Input file name. (default: perf.data)
+        Input file name. (default: perf.data unless stdin is a fifo)
 
 SEE ALSO
 --------

tools/perf/Documentation/perf-kmem.txt

···
 -------
 -i <file>::
 --input=<file>::
-	Select the input file (default: perf.data)
+	Select the input file (default: perf.data unless stdin is a fifo)
 
 --caller::
 	Show per-callsite statistics

tools/perf/Documentation/perf-lock.txt

···
 
 -i::
 --input=<file>::
-        Input file name.
+        Input file name. (default: perf.data unless stdin is a fifo)
 
 -v::
 --verbose::

tools/perf/Documentation/perf-report.txt

···
 -------
 -i::
 --input=::
-        Input file name. (default: perf.data)
+        Input file name. (default: perf.data unless stdin is a fifo)
 
 -v::
 --verbose::

tools/perf/Documentation/perf-sched.txt

···
 -------
 -i::
 --input=<file>::
-        Input file name. (default: perf.data)
+        Input file name. (default: perf.data unless stdin is a fifo)
 
 -v::
 --verbose::

tools/perf/Documentation/perf-script.txt

···
 
 -i::
 --input=::
-        Input file name.
+        Input file name. (default: perf.data unless stdin is a fifo)
 
 -d::
 --debug-mode::

tools/perf/Documentation/perf-timechart.txt

···
         Select the output file (default: output.svg)
 -i::
 --input=::
-        Select the input file (default: perf.data)
+        Select the input file (default: perf.data unless stdin is a fifo)
 -w::
 --width=::
         Select the width of the SVG file (default: 1000)

tools/perf/builtin-annotate.c

···
 	}
 
 	if (total_nr_samples == 0) {
-		ui__warning("The %s file has no samples!\n", ann->input_name);
+		ui__warning("The %s file has no samples!\n", session->filename);
 		goto out_delete;
 	}
 out_delete:
···
 			.ordered_samples = true,
 			.ordering_requires_timestamps = true,
 		},
-		.input_name = "perf.data",
 	};
 	const struct option options[] = {
 	OPT_STRING('i', "input", &annotate.input_name, "file",

tools/perf/builtin-buildid-list.c

···
 
 #include <libelf.h>
 
-static char const *input_name = "perf.data";
+static const char *input_name;
 static bool force;
 static bool show_kernel;
 static bool with_hits;
···
 {
 	struct perf_session *session;
 
+	elf_version(EV_CURRENT);
+
 	session = perf_session__new(input_name, O_RDONLY, force, false,
 				    &build_id__mark_dso_hit_ops);
 	if (session == NULL)
 		return -1;
 
+	/*
+	 * See if this is an ELF file first:
+	 */
+	if (filename__fprintf_build_id(session->filename, stdout))
+		goto out;
+
 	if (with_hits)
 		perf_session__process_events(session, &build_id__mark_dso_hit_ops);
 
 	perf_session__fprintf_dsos_buildid(session, stdout, with_hits);
-
+out:
 	perf_session__delete(session);
 	return 0;
 }
···
 {
 	if (show_kernel)
 		return sysfs__fprintf_build_id(stdout);
-
-	elf_version(EV_CURRENT);
-	/*
- 	 * See if this is an ELF file first:
- 	 */
-	if (filename__fprintf_build_id(input_name, stdout))
-		return 0;
 
 	return perf_session__list_build_ids();
 }

tools/perf/builtin-evlist.c

···
 #include "util/parse-options.h"
 #include "util/session.h"
 
-static char const *input_name = "perf.data";
+static const char *input_name;
 
 static int __cmd_evlist(void)
 {

tools/perf/builtin-kmem.c

···
 struct alloc_stat;
 typedef int (*sort_fn_t)(struct alloc_stat *, struct alloc_stat *);
 
-static char const		*input_name = "perf.data";
+static const char		*input_name;
 
 static int			alloc_flag;
 static int			caller_flag;

tools/perf/builtin-lock.c

···
 	die("memory allocation failed\n");
 }
 
-static char			const *input_name = "perf.data";
+static const char *input_name;
 
 struct raw_event_sample {
 	u32			size;

tools/perf/builtin-report.c

···
 	}
 
 	if (nr_samples == 0) {
-		ui__warning("The %s file has no samples!\n",
-			    rep->input_name);
+		ui__warning("The %s file has no samples!\n", session->filename);
 		goto out_delete;
 	}
 
···
 
 int cmd_report(int argc, const char **argv, const char *prefix __used)
 {
+	struct stat st;
 	char callchain_default_opt[] = "fractal,0.5,callee";
 	const char * const report_usage[] = {
 		"perf report [<options>]",
···
 			.ordered_samples = true,
 			.ordering_requires_timestamps = true,
 		},
-		.input_name		 = "perf.data",
 		.pretty_printing_style	 = "normal",
 	};
 	const struct option options[] = {
···
 	if (report.inverted_callchain)
 		callchain_param.order = ORDER_CALLER;
 
+	if (!report.input_name || !strlen(report.input_name)) {
+		if (!fstat(STDIN_FILENO, &st) && S_ISFIFO(st.st_mode))
+			report.input_name = "-";
+		else
+			report.input_name = "perf.data";
+	}
+
 	if (strcmp(report.input_name, "-") != 0)
 		setup_browser(true);
 	else
 		use_browser = 0;
+
 	/*
 	 * Only in the newt browser we are doing integrated annotation,
 	 * so don't allocate extra space that won't be used in the stdio

tools/perf/builtin-sched.c

···
 #include <pthread.h>
 #include <math.h>
 
-static char			const *input_name = "perf.data";
+static const char		*input_name;
 
 static char			default_sort_order[] = "avg, max, switch, runtime";
 static const char		*sort_order = default_sort_order;

tools/perf/builtin-script.c

···
 	return scripting_ops->stop_script();
 }
 
-static char const		*input_name = "perf.data";
+static const char *input_name;
 
 static int process_sample_event(struct perf_tool *tool __used,
 				union perf_event *event,
···
 			return -1;
 		}
 
-		input = open(input_name, O_RDONLY);
+		input = open(session->filename, O_RDONLY);	/* input_name */
 		if (input < 0) {
 			perror("failed to open file");
 			exit(-1);

tools/perf/builtin-timechart.c

···
 #define PWR_EVENT_EXIT -1
 
 
-static char		const *input_name = "perf.data";
-static char		const *output_name = "output.svg";
+static const char	*input_name;
+static const char	*output_name = "output.svg";
 
 static unsigned int	numcpus;
 static u64		min_freq;	/* Lowest CPU frequency seen */

tools/perf/util/session.c

···
 				       bool force, bool repipe,
 				       struct perf_tool *tool)
 {
-	size_t len = filename ? strlen(filename) : 0;
-	struct perf_session *self = zalloc(sizeof(*self) + len);
+	struct perf_session *self;
+	struct stat st;
+	size_t len;
+
+	if (!filename || !strlen(filename)) {
+		if (!fstat(STDIN_FILENO, &st) && S_ISFIFO(st.st_mode))
+			filename = "-";
+		else
+			filename = "perf.data";
+	}
+
+	len = strlen(filename);
+	self = zalloc(sizeof(*self) + len);
 
 	if (self == NULL)
 		goto out;