perf tools: Generalize event synthesizing routines

Because we will need it in 'perf top' to support userspace
symbols for existing threads.

Now we pass a callback that will receive the synthesized event
and then write it to the output file in 'perf record' and in the
upcoming patch for 'perf top' we will just immediatelly create
the in memory representation of threads and maps.

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Mike Galbraith <efault@gmx.de>
LKML-Reference: <1256592199-9608-2-git-send-email-acme@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 177 insertions, 0 deletions

diff --git a/tools/perf/util/event.c b/tools/perf/util/event.c
new file mode 100644
index 0000000..1dae7e3
--- /dev/null
+++ b/tools/perf/util/event.c
@@ -0,0 +1,177 @@
+#include <linux/types.h>
+#include "event.h"
+#include "debug.h"
+#include "string.h"
+
+static pid_t event__synthesize_comm(pid_t pid, int full,
+				    int (*process)(event_t *event))
+{
+	event_t ev;
+	char filename[PATH_MAX];
+	char bf[BUFSIZ];
+	FILE *fp;
+	size_t size = 0;
+	DIR *tasks;
+	struct dirent dirent, *next;
+	pid_t tgid = 0;
+
+	snprintf(filename, sizeof(filename), "/proc/%d/status", pid);
+
+	fp = fopen(filename, "r");
+	if (fp == NULL) {
+out_race:
+		/*
+		 * We raced with a task exiting - just return:
+		 */
+		pr_debug("couldn't open %s\n", filename);
+		return 0;
+	}
+
+	memset(&ev.comm, 0, sizeof(ev.comm));
+	while (!ev.comm.comm[0] || !ev.comm.pid) {
+		if (fgets(bf, sizeof(bf), fp) == NULL)
+			goto out_failure;
+
+		if (memcmp(bf, "Name:", 5) == 0) {
+			char *name = bf + 5;
+			while (*name && isspace(*name))
+				++name;
+			size = strlen(name) - 1;
+			memcpy(ev.comm.comm, name, size++);
+		} else if (memcmp(bf, "Tgid:", 5) == 0) {
+			char *tgids = bf + 5;
+			while (*tgids && isspace(*tgids))
+				++tgids;
+			tgid = ev.comm.pid = atoi(tgids);
+		}
+	}
+
+	ev.comm.header.type = PERF_RECORD_COMM;
+	size = ALIGN(size, sizeof(u64));
+	ev.comm.header.size = sizeof(ev.comm) - (sizeof(ev.comm.comm) - size);
+
+	if (!full) {
+		ev.comm.tid = pid;
+
+		process(&ev);
+		goto out_fclose;
+	}
+
+	snprintf(filename, sizeof(filename), "/proc/%d/task", pid);
+
+	tasks = opendir(filename);
+	if (tasks == NULL)
+		goto out_race;
+
+	while (!readdir_r(tasks, &dirent, &next) && next) {
+		char *end;
+		pid = strtol(dirent.d_name, &end, 10);
+		if (*end)
+			continue;
+
+		ev.comm.tid = pid;
+
+		process(&ev);
+	}
+	closedir(tasks);
+
+out_fclose:
+	fclose(fp);
+	return tgid;
+
+out_failure:
+	pr_warning("couldn't get COMM and pgid, malformed %s\n", filename);
+	return -1;
+}
+
+static int event__synthesize_mmap_events(pid_t pid, pid_t tgid,
+					 int (*process)(event_t *event))
+{
+	char filename[PATH_MAX];
+	FILE *fp;
+
+	snprintf(filename, sizeof(filename), "/proc/%d/maps", pid);
+
+	fp = fopen(filename, "r");
+	if (fp == NULL) {
+		/*
+		 * We raced with a task exiting - just return:
+		 */
+		pr_debug("couldn't open %s\n", filename);
+		return -1;
+	}
+
+	while (1) {
+		char bf[BUFSIZ], *pbf = bf;
+		event_t ev = {
+			.header = { .type = PERF_RECORD_MMAP },
+		};
+		int n;
+		size_t size;
+		if (fgets(bf, sizeof(bf), fp) == NULL)
+			break;
+
+		/* 00400000-0040c000 r-xp 00000000 fd:01 41038  /bin/cat */
+		n = hex2u64(pbf, &ev.mmap.start);
+		if (n < 0)
+			continue;
+		pbf += n + 1;
+		n = hex2u64(pbf, &ev.mmap.len);
+		if (n < 0)
+			continue;
+		pbf += n + 3;
+		if (*pbf == 'x') { /* vm_exec */
+			char *execname = strchr(bf, '/');
+
+			/* Catch VDSO */
+			if (execname == NULL)
+				execname = strstr(bf, "[vdso]");
+
+			if (execname == NULL)
+				continue;
+
+			size = strlen(execname);
+			execname[size - 1] = '\0'; /* Remove \n */
+			memcpy(ev.mmap.filename, execname, size);
+			size = ALIGN(size, sizeof(u64));
+			ev.mmap.len -= ev.mmap.start;
+			ev.mmap.header.size = (sizeof(ev.mmap) -
+					       (sizeof(ev.mmap.filename) - size));
+			ev.mmap.pid = tgid;
+			ev.mmap.tid = pid;
+
+			process(&ev);
+		}
+	}
+
+	fclose(fp);
+	return 0;
+}
+
+int event__synthesize_thread(pid_t pid, int (*process)(event_t *event))
+{
+	pid_t tgid = event__synthesize_comm(pid, 1, process);
+	if (tgid == -1)
+		return -1;
+	return event__synthesize_mmap_events(pid, tgid, process);
+}
+
+void event__synthesize_threads(int (*process)(event_t *event))
+{
+	DIR *proc;
+	struct dirent dirent, *next;
+
+	proc = opendir("/proc");
+
+	while (!readdir_r(proc, &dirent, &next) && next) {
+		char *end;
+		pid_t pid = strtol(dirent.d_name, &end, 10);
+
+		if (*end) /* only interested in proper numerical dirents */
+			continue;
+
+		event__synthesize_thread(pid, process);
+	}
+
+	closedir(proc);
+}