[tip:perfcounters/core] perf_counter tools: Add built-in pager support

tip-bot for Ingo Molnar
2009-05-27T09:07:27Z

Commit-ID: a930d2c0d0a685ab955472b08baad041cc5edb4a
Gitweb: http://git.kernel.org/tip/a930d2c0d0a685ab955472b08baad041cc5edb4a
Author: Ingo Molnar <mingo@elte.hu>
AuthorDate: Wed, 27 May 2009 09:50:13 +0200
Committer: Ingo Molnar <mingo@elte.hu>
CommitDate: Wed, 27 May 2009 09:59:00 +0200

perf_counter tools: Add built-in pager support

Add Git's pager.c (and sigchain) code. A command only
has to call setup_pager() to get paged interactive
output.

Non-interactive (redirected, command-piped, etc.) uses
are not affected.

Update perf-report to make use of this.

[ Impact: new feature ]

Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: John Kacur <jkacur@redhat.com>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

---
Documentation/perf_counter/Makefile | 4 +
Documentation/perf_counter/builtin-report.c | 3 +
Documentation/perf_counter/util/environment.c | 8 ++
Documentation/perf_counter/util/pager.c | 99 +++++++++++++++++++++++++
Documentation/perf_counter/util/sigchain.c | 52 +++++++++++++
Documentation/perf_counter/util/sigchain.h | 11 +++
6 files changed, 177 insertions(+), 0 deletions(-)

diff --git a/Documentation/perf_counter/Makefile b/Documentation/perf_counter/Makefile
index efb0589..51b13f9 100644
--- a/Documentation/perf_counter/Makefile
+++ b/Documentation/perf_counter/Makefile
@@ -297,11 +297,13 @@ LIB_H += util/util.h
LIB_H += util/help.h
LIB_H += util/strbuf.h
LIB_H += util/run-command.h
+LIB_H += util/sigchain.h

LIB_OBJS += util/abspath.o
LIB_OBJS += util/alias.o
LIB_OBJS += util/config.o
LIB_OBJS += util/ctype.o
+LIB_OBJS += util/environment.o
LIB_OBJS += util/exec_cmd.o
LIB_OBJS += util/help.o
LIB_OBJS += util/levenshtein.o
@@ -314,6 +316,8 @@ LIB_OBJS += util/quote.o
LIB_OBJS += util/strbuf.o
LIB_OBJS += util/usage.o
LIB_OBJS += util/wrapper.o
+LIB_OBJS += util/sigchain.o
+LIB_OBJS += util/pager.o

BUILTIN_OBJS += builtin-help.o
BUILTIN_OBJS += builtin-record.o
diff --git a/Documentation/perf_counter/builtin-report.c b/Documentation/perf_counter/builtin-report.c
index e2712cd..9aef7c5 100644
--- a/Documentation/perf_counter/builtin-report.c
+++ b/Documentation/perf_counter/builtin-report.c
@@ -7,6 +7,7 @@
#include <ctype.h>

#include "util/list.h"
+#include "util/cache.h"
#include "util/rbtree.h"

#include "perf.h"
@@ -992,5 +993,7 @@ int cmd_report(int argc, const char **argv, const char *prefix)

parse_options(argc, argv, options, report_usage, 0);

+ setup_pager();
+
return __cmd_report();
}
diff --git a/Documentation/perf_counter/util/environment.c b/Documentation/perf_counter/util/environment.c
new file mode 100644
index 0000000..9b1c819
--- /dev/null
+++ b/Documentation/perf_counter/util/environment.c
@@ -0,0 +1,8 @@
+/*
+ * We put all the perf config variables in this same object
+ * file, so that programs can link against the config parser
+ * without having to link against all the rest of perf.
+ */
+#include "cache.h"
+
+const char *pager_program;
diff --git a/Documentation/perf_counter/util/pager.c b/Documentation/perf_counter/util/pager.c
new file mode 100644
index 0000000..a28bcca
--- /dev/null
+++ b/Documentation/perf_counter/util/pager.c
@@ -0,0 +1,99 @@
+#include "cache.h"
+#include "run-command.h"
+#include "sigchain.h"
+
+/*
+ * This is split up from the rest of git so that we can do
+ * something different on Windows.
+ */
+
+static int spawned_pager;
+
+#ifndef __MINGW32__
+static void pager_preexec(void)
+{
+ /*
+ * Work around bug in "less" by not starting it until we
+ * have real input
+ */
+ fd_set in;
+
+ FD_ZERO(&in);
+ FD_SET(0, &in);
+ select(1, &in, NULL, &in, NULL);
+
+ setenv("LESS", "FRSX", 0);
+}
+#endif
+
+static const char *pager_argv[] = { "sh", "-c", NULL, NULL };
+static struct child_process pager_process;
+
+static void wait_for_pager(void)
+{
+ fflush(stdout);
+ fflush(stderr);
+ /* signal EOF to pager */
+ close(1);
+ close(2);
+ finish_command(&pager_process);
+}
+
+static void wait_for_pager_signal(int signo)
+{
+ wait_for_pager();
+ sigchain_pop(signo);
+ raise(signo);
+}
+
+void setup_pager(void)
+{
+ const char *pager = getenv("PERF_PAGER");
+
+ if (!isatty(1))
+ return;
+ if (!pager) {
+ if (!pager_program)
+ perf_config(perf_default_config, NULL);
+ pager = pager_program;
+ }
+ if (!pager)
+ pager = getenv("PAGER");
+ if (!pager)
+ pager = "less";
+ else if (!*pager || !strcmp(pager, "cat"))
+ return;
+
+ spawned_pager = 1; /* means we are emitting to terminal */
+
+ /* spawn the pager */
+ pager_argv[2] = pager;
+ pager_process.argv = pager_argv;
+ pager_process.in = -1;
+#ifndef __MINGW32__
+ pager_process.preexec_cb = pager_preexec;
+#endif
+ if (start_command(&pager_process))
+ return;
+
+ /* original process continues, but writes to the pipe */
+ dup2(pager_process.in, 1);
+ if (isatty(2))
+ dup2(pager_process.in, 2);
+ close(pager_process.in);
+
+ /* this makes sure that the parent terminates after the pager */
+ sigchain_push_common(wait_for_pager_signal);
+ atexit(wait_for_pager);
+}
+
+int pager_in_use(void)
+{
+ const char *env;
+
+ if (spawned_pager)
+ return 1;
+
+ env = getenv("PERF_PAGER_IN_USE");
+ return env ? perf_config_bool("PERF_PAGER_IN_USE", env) : 0;
+}
diff --git a/Documentation/perf_counter/util/sigchain.c b/Documentation/perf_counter/util/sigchain.c
new file mode 100644
index 0000000..1118b99
--- /dev/null
+++ b/Documentation/perf_counter/util/sigchain.c
@@ -0,0 +1,52 @@
+#include "sigchain.h"
+#include "cache.h"
+
+#define SIGCHAIN_MAX_SIGNALS 32
+
+struct sigchain_signal {
+ sigchain_fun *old;
+ int n;
+ int alloc;
+};
+static struct sigchain_signal signals[SIGCHAIN_MAX_SIGNALS];
+
+static void check_signum(int sig)
+{
+ if (sig < 1 || sig >= SIGCHAIN_MAX_SIGNALS)
+ die("BUG: signal out of range: %d", sig);
+}
+
+int sigchain_push(int sig, sigchain_fun f)
+{
+ struct sigchain_signal *s = signals + sig;
+ check_signum(sig);
+
+ ALLOC_GROW(s->old, s->n + 1, s->alloc);
+ s->old[s->n] = signal(sig, f);
+ if (s->old[s->n] == SIG_ERR)
+ return -1;
+ s->n++;
+ return 0;
+}
+
+int sigchain_pop(int sig)
+{
+ struct sigchain_signal *s = signals + sig;
+ check_signum(sig);
+ if (s->n < 1)
+ return 0;
+
+ if (signal(sig, s->old[s->n - 1]) == SIG_ERR)
+ return -1;
+ s->n--;
+ return 0;
+}
+
+void sigchain_push_common(sigchain_fun f)
+{
+ sigchain_push(SIGINT, f);
+ sigchain_push(SIGHUP, f);
+ sigchain_push(SIGTERM, f);
+ sigchain_push(SIGQUIT, f);
+ sigchain_push(SIGPIPE, f);
+}
diff --git a/Documentation/perf_counter/util/sigchain.h b/Documentation/perf_counter/util/sigchain.h
new file mode 100644
index 0000000..618083b
--- /dev/null
+++ b/Documentation/perf_counter/util/sigchain.h
@@ -0,0 +1,11 @@
+#ifndef SIGCHAIN_H
+#define SIGCHAIN_H
+
+typedef void (*sigchain_fun)(int);
+
+int sigchain_push(int sig, sigchain_fun f);
+int sigchain_pop(int sig);
+
+void sigchain_push_common(sigchain_fun f);
+
+#endif /* SIGCHAIN_H */