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 <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1323248577-11268-5-git-send-email-robert.richter@amd.com
Signed-off-by: Robert Richter <robert.richter@amd.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/tools/perf/Documentation/perf-annotate.txt b/tools/perf/Documentation/perf-annotate.txt
index 476029d..c89f9e1 100644
--- a/tools/perf/Documentation/perf-annotate.txt
+++ b/tools/perf/Documentation/perf-annotate.txt
@@ -22,7 +22,7 @@
 -------
 -i::
 --input=::
-        Input file name. (default: perf.data)
+        Input file name. (default: perf.data unless stdin is a fifo)
 
 -d::
 --dsos=<dso[,dso...]>::
diff --git a/tools/perf/Documentation/perf-buildid-list.txt b/tools/perf/Documentation/perf-buildid-list.txt
index cc22325..25c52ef 100644
--- a/tools/perf/Documentation/perf-buildid-list.txt
+++ b/tools/perf/Documentation/perf-buildid-list.txt
@@ -26,7 +26,7 @@
         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.
diff --git a/tools/perf/Documentation/perf-evlist.txt b/tools/perf/Documentation/perf-evlist.txt
index 0cada9e..0507ec7 100644
--- a/tools/perf/Documentation/perf-evlist.txt
+++ b/tools/perf/Documentation/perf-evlist.txt
@@ -18,7 +18,7 @@
 -------
 -i::
 --input=::
-        Input file name. (default: perf.data)
+        Input file name. (default: perf.data unless stdin is a fifo)
 
 SEE ALSO
 --------
diff --git a/tools/perf/Documentation/perf-kmem.txt b/tools/perf/Documentation/perf-kmem.txt
index a52fcde..7c8fbbf 100644
--- a/tools/perf/Documentation/perf-kmem.txt
+++ b/tools/perf/Documentation/perf-kmem.txt
@@ -23,7 +23,7 @@
 -------
 -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
diff --git a/tools/perf/Documentation/perf-lock.txt b/tools/perf/Documentation/perf-lock.txt
index 4a26a2f..d6b2a4f 100644
--- a/tools/perf/Documentation/perf-lock.txt
+++ b/tools/perf/Documentation/perf-lock.txt
@@ -29,7 +29,7 @@
 
 -i::
 --input=<file>::
-        Input file name.
+        Input file name. (default: perf.data unless stdin is a fifo)
 
 -v::
 --verbose::
diff --git a/tools/perf/Documentation/perf-report.txt b/tools/perf/Documentation/perf-report.txt
index 35af0dc..9b430e9 100644
--- a/tools/perf/Documentation/perf-report.txt
+++ b/tools/perf/Documentation/perf-report.txt
@@ -19,7 +19,7 @@
 -------
 -i::
 --input=::
-        Input file name. (default: perf.data)
+        Input file name. (default: perf.data unless stdin is a fifo)
 
 -v::
 --verbose::
diff --git a/tools/perf/Documentation/perf-sched.txt b/tools/perf/Documentation/perf-sched.txt
index 5b212b5..8ff4df9 100644
--- a/tools/perf/Documentation/perf-sched.txt
+++ b/tools/perf/Documentation/perf-sched.txt
@@ -40,7 +40,7 @@
 -------
 -i::
 --input=<file>::
-        Input file name. (default: perf.data)
+        Input file name. (default: perf.data unless stdin is a fifo)
 
 -v::
 --verbose::
diff --git a/tools/perf/Documentation/perf-script.txt b/tools/perf/Documentation/perf-script.txt
index 7f61eaa..2f6cef4 100644
--- a/tools/perf/Documentation/perf-script.txt
+++ b/tools/perf/Documentation/perf-script.txt
@@ -106,7 +106,7 @@
 
 -i::
 --input=::
-        Input file name.
+        Input file name. (default: perf.data unless stdin is a fifo)
 
 -d::
 --debug-mode::
diff --git a/tools/perf/Documentation/perf-timechart.txt b/tools/perf/Documentation/perf-timechart.txt
index d7b79e2..1632b0e 100644
--- a/tools/perf/Documentation/perf-timechart.txt
+++ b/tools/perf/Documentation/perf-timechart.txt
@@ -27,7 +27,7 @@
         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)