[PATCH] bugfix: fix some bugs about combination of -b and -S on old kernel

[Masami Hiramatsu <mhiramat at redhat dot com>]

Hi,

Here is a patch which fixes some bugs when we give stap
-b (bulk mode) and -S (file-switching) on old kernel(e.g. RHEL4)

This fixes staprun to pass flightrec3.exp testcase.

Thank you,

-- 
Masami Hiramatsu

Software Engineer
Hitachi Computer Products (America), Inc.
Software Solutions Division

e-mail: mhiramat@redhat.com

Fix on-file flight recorder mode bugs on old kernel.

From: Masami Hiramatsu <mhiramat@redhat.com>

* runtime/staprun/common.c (make_outfile_name): Moved from relay.c, fix not to
  open /dev/null.XXX output files, and add 'bulk' argument for bulkmode.
* runtime/staprun/relay.c (make_outfile_name): Moved to common.c.
* runtime/staprun/relay_old.c (open_oldoutfile): Fix to use fopen() and store
  FILE * to percpu_tmpfile[cpu].
---

 runtime/staprun/common.c    |   27 +++++++++++++++++++++++++++
 runtime/staprun/relay.c     |   30 +++---------------------------
 runtime/staprun/relay_old.c |   17 ++++++++++-------
 runtime/staprun/staprun.h   |    3 ++-
 4 files changed, 42 insertions(+), 35 deletions(-)


diff --git a/runtime/staprun/common.c b/runtime/staprun/common.c
index c67ce34..5c4a843 100644
--- a/runtime/staprun/common.c
+++ b/runtime/staprun/common.c
@@ -66,6 +66,33 @@ int stap_strfloctime(char *buf, size_t max, const char *fmt, time_t t)
 	return (int)ret;
 }
 
+int make_outfile_name(char *buf, int max, int fnum, int cpu, time_t t, int bulk)
+{
+	int len;
+	if (PATH_MAX < max)
+		max = PATH_MAX;
+	len = stap_strfloctime(buf, max, outfile_name, t);
+	if (len < 0) {
+		err("Invalid FILE name format\n");
+		return -1;
+	}
+	/* special case: for testing we sometimes want to write to /dev/null */
+	if (strcmp(outfile_name, "/dev/null") == 0) {
+		strcpy(buf, "/dev/null");
+	} else {
+		if (bulk) {
+			if (snprintf_chk(&buf[len], max - len, "_cpu%d.%d",
+					 cpu, fnum))
+				return -1;
+		} else {
+			/* stream mode */
+			if (snprintf_chk(&buf[len], max - len, ".%d", fnum))
+				return -1;
+		}
+	}
+	return 0;
+}
+
 void parse_args(int argc, char **argv)
 {
 	int c;
diff --git a/runtime/staprun/relay.c b/runtime/staprun/relay.c
index b979624..f4aa139 100644
--- a/runtime/staprun/relay.c
+++ b/runtime/staprun/relay.c
@@ -73,31 +73,6 @@ time_t read_backlog(int cpu, int fnum)
 	return time_backlog[cpu][fnum & BACKLOG_MASK];
 }
 
-int make_outfile_name(char *buf, int max, int fnum, int cpu, time_t t)
-{
-	int len;
-	len = stap_strfloctime(buf, max, outfile_name, t);
-	if (len < 0) {
-		err("Invalid FILE name format\n");
-  		return -1;
-  	}
-	if (bulkmode) {
-		/* special case: for testing we sometimes want to write to /dev/null */
-		if (strcmp(outfile_name, "/dev/null") == 0) {
-			strcpy(buf, "/dev/null");
-		} else {
-			if (snprintf_chk(&buf[len], PATH_MAX - len,
-					 "_cpu%d.%d", cpu, fnum))
-				return -1;
-		}
-	} else {
-		/* stream mode */
-		if (snprintf_chk(&buf[len], PATH_MAX - len, ".%d", fnum))
-			return -1;
-	}
-	return 0;
-}
-
 static int open_outfile(int fnum, int cpu, int remove_file)
 {
 	char buf[PATH_MAX];
@@ -112,14 +87,15 @@ static int open_outfile(int fnum, int cpu, int remove_file)
 		if (remove_file) {
 			 /* remove oldest file */
 			if (make_outfile_name(buf, PATH_MAX, fnum - fnum_max,
-				 cpu, read_backlog(cpu, fnum - fnum_max)) < 0)
+				 cpu, read_backlog(cpu, fnum - fnum_max),
+				 bulkmode) < 0)
 				return -1;
 			remove(buf); /* don't care */
 		}
 		write_backlog(cpu, fnum, t);
 	}
 
-	if (make_outfile_name(buf, PATH_MAX, fnum, cpu, t) < 0)
+	if (make_outfile_name(buf, PATH_MAX, fnum, cpu, t, bulkmode) < 0)
 		return -1;
 	out_fd[cpu] = open (buf, O_CREAT|O_TRUNC|O_WRONLY, 0666);
 	if (out_fd[cpu] < 0) {
diff --git a/runtime/staprun/relay_old.c b/runtime/staprun/relay_old.c
index 33d2daf..71d8ace 100644
--- a/runtime/staprun/relay_old.c
+++ b/runtime/staprun/relay_old.c
@@ -87,30 +87,33 @@ static int open_oldoutfile(int fnum, int cpu, int remove_file)
 		if (fnum_max) {
 			if (remove_file) {
 				 /* remove oldest file */
-				if (make_outfile_name(buf, PATH_MAX, fnum - fnum_max,
-					 cpu, read_backlog(cpu, fnum - fnum_max)) < 0)
+				if (make_outfile_name(buf, PATH_MAX,
+					fnum - fnum_max, cpu,
+					read_backlog(cpu, fnum - fnum_max),
+					bulkmode) < 0)
 					return -1;
 				remove(buf); /* don't care */
 			}
 			write_backlog(cpu, fnum, t);
 		}
-		if (make_outfile_name(buf, PATH_MAX, fnum, cpu, t) < 0)
+		if (make_outfile_name(buf, PATH_MAX, fnum, cpu, t, bulkmode) < 0)
 			return -1;
 	} else if (bulkmode) {
 		if (sprintf_chk(buf, "stpd_cpu%d.%d", cpu, fnum))
 			return -1;
 	} else { /* stream mode */
-		out_fd[cpu] = STDOUT_FILENO;
+		percpu_tmpfile[cpu] = stdout;
 		return 0;
 	}
 
-	out_fd[cpu] = open (buf, O_CREAT|O_TRUNC|O_WRONLY, 0666);
-	if (out_fd[cpu] < 0) {
+	if((percpu_tmpfile[cpu] = fopen(buf, "w+")) == NULL) {
 		perr("Couldn't open output file %s", buf);
 		return -1;
 	}
-	if (set_clexec(out_fd[cpu]) < 0)
+	if (set_clexec(fileno(percpu_tmpfile[cpu])) < 0) {
+		perr("Couldn't clear exec bit of open output file %s", buf);
 		return -1;
+	}
 	return 0;
 }
 /**
diff --git a/runtime/staprun/staprun.h b/runtime/staprun/staprun.h
index bd6402e..3c9dab3 100644
--- a/runtime/staprun/staprun.h
+++ b/runtime/staprun/staprun.h
@@ -120,7 +120,8 @@ int init_oldrelayfs(void);
 void close_oldrelayfs(int);
 int write_realtime_data(void *data, ssize_t nb);
 void setup_signals(void);
-int make_outfile_name(char *buf, int max, int fnum, int cpu, time_t t);
+int make_outfile_name(char *buf, int max, int fnum, int cpu,
+		      time_t t, int bulk);
 int init_backlog(int cpu);
 void write_backlog(int cpu, int fnum, time_t t);
 time_t read_backlog(int cpu, int fnum);