Fix the way the segments are included in the gcore outputs (with the

default invokation):
- Right now if segments are not writable are not included. Remove this.
- Right now if a segment is mapped with NOCORE the check is not honoured.
  Change this by checking the newly added flag, from libutil,
  KVME_FLAG_NOCOREDUMP.

Besides that, add a new flag (-f) that forces a 'full' dump of all the
segments excluding just the malformed ones. This might be used very
carefully as, among the reported segments, there could be memory
mapped areas that could be vital to program execution.

Sponsored by:	Sandvine Incorporated
Discussed with:	kib
Reviewed by:	emaste
Tested by:	Sandvine Incorporated
MFC after:	2 weeks

4 files changed, 30 insertions, 11 deletions

diff --git a/usr.bin/gcore/elfcore.c b/usr.bin/gcore/elfcore.c
index 73d92b4..5d655c3 100644
--- a/usr.bin/gcore/elfcore.c
+++ b/usr.bin/gcore/elfcore.c
@@ -488,12 +488,17 @@ readmap(pid_t pid)
 		kve = &vmentl[i];
 
 		/*
-		 * Ignore segments of the wrong kind and ones which are not
-		 * readable and writable.
+		 * Ignore 'malformed' segments or ones representing memory
+		 * mapping with MAP_NOCORE on.
+		 * If the 'full' support is disabled, just dump the most
+		 * meaningful data segments.
 		 */
-		if ((kve->kve_protection & KVME_PROT_WRITE) == 0 ||
-		    (kve->kve_protection & KVME_PROT_READ) == 0 ||
-		    (kve->kve_type != KVME_TYPE_DEFAULT &&
+		if ((kve->kve_protection & KVME_PROT_READ) == 0 ||
+		    (kve->kve_flags & KVME_FLAG_NOCOREDUMP) != 0 ||
+		    kve->kve_type == KVME_TYPE_DEAD ||
+		    kve->kve_type == KVME_TYPE_UNKNOWN ||
+		    ((pflags & PFLAGS_FULL) == 0 &&
+		    kve->kve_type != KVME_TYPE_DEFAULT &&
 		    kve->kve_type != KVME_TYPE_VNODE &&
 		    kve->kve_type != KVME_TYPE_SWAP))
 			continue;
diff --git a/usr.bin/gcore/extern.h b/usr.bin/gcore/extern.h
index 68e05a78..fc3566c 100644
--- a/usr.bin/gcore/extern.h
+++ b/usr.bin/gcore/extern.h
@@ -34,8 +34,11 @@
  * $FreeBSD$
  */
 
+#define	PFLAGS_FULL	0x01
+#define	PFLAGS_RESUME	0x02
+
 struct dumpers {
 	int (*ident)(int efd, pid_t pid, char *binfile);
 	void (*dump)(int efd, int fd, pid_t pid);
 };
-extern int sflag;
+extern int pflags;
diff --git a/usr.bin/gcore/gcore.1 b/usr.bin/gcore/gcore.1
index a5be26a..7d7cc82 100644
--- a/usr.bin/gcore/gcore.1
+++ b/usr.bin/gcore/gcore.1
@@ -32,7 +32,7 @@
 .\"	@(#)gcore.1	8.2 (Berkeley) 4/18/94
 .\" $FreeBSD$
 .\"
-.Dd November 18, 2009
+.Dd July 14, 2010
 .Dt GCORE 1
 .Os
 .Sh NAME
@@ -40,6 +40,7 @@
 .Nd get core images of running process
 .Sh SYNOPSIS
 .Nm
+.Op Fl f
 .Op Fl s
 .Op Fl c Ar core
 .Op Ar executable
@@ -61,6 +62,13 @@ The following options are available:
 .It Fl c
 Write the core file to the specified file instead of
 .Dq Pa core.<pid> .
+.It Fl f
+Dumps all the available segments, excluding only the malformed ones and
+un-dumpable ones. Differently from the default invocation, it also dumps
+device-mapped and sglist-mapped areas that may invalidate the state of
+some transactions. This flag, then, may be used very carefully, when the
+full behaviour of the application is full-understood and the fallouts can
+be easilly controlled.
 .It Fl s
 Stop the process while gathering the core image, and resume it
 when done.
diff --git a/usr.bin/gcore/gcore.c b/usr.bin/gcore/gcore.c
index b02a4a9..c45a3a5 100644
--- a/usr.bin/gcore/gcore.c
+++ b/usr.bin/gcore/gcore.c
@@ -71,7 +71,7 @@ __FBSDID("$FreeBSD$");
 #include <unistd.h>
 
 #include "extern.h"
-int sflag;
+int pflags;
 
 static void	killed(int);
 static void	usage(void) __dead2;
@@ -89,15 +89,18 @@ main(int argc, char *argv[])
 	struct dumpers **d, *dumper;
 	size_t len;
 
-	sflag = 0;
+	pflags = 0;
 	corefile = NULL;
-        while ((ch = getopt(argc, argv, "c:s")) != -1) {
+        while ((ch = getopt(argc, argv, "c:fs")) != -1) {
                 switch (ch) {
                 case 'c':
 			corefile = optarg;
                         break;
+		case 'f':
+			pflags |= PFLAGS_FULL;
+			break;
 		case 's':
-			sflag = 1;
+			pflags |= PFLAGS_RESUME;
 			break;
 		default:
 			usage();