perf buildid-cache: Support binary objects from other namespaces

Teach buildid-cache how to add, remove, and update binary objects from
other mount namespaces.  Allow probe events tracing binaries in
different namespaces to add their objects to the probe and build-id
caches too.  As a handy side effect, this also lets us access SDT probes
in binaries from alternate mount namespaces.

Signed-off-by: Krister Johansen <kjlx@templeofstupid.com>
Tested-by: Brendan Gregg <brendan.d.gregg@gmail.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas-Mich Richter <tmricht@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/r/1499305693-1599-5-git-send-email-kjlx@templeofstupid.com
[ Add util/namespaces.c to tools/perf/util/python-ext-sources, to fix the python binding 'perf test' ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 28 insertions, 6 deletions

diff --git a/tools/perf/util/util.c b/tools/perf/util/util.c
index 988111e0bab5..9e4ea852f636 100644
--- a/tools/perf/util/util.c
+++ b/tools/perf/util/util.c
@@ -143,13 +143,17 @@ out:
 	return list;
 }
 
-static int slow_copyfile(const char *from, const char *to)
+static int slow_copyfile(const char *from, const char *to, struct nsinfo *nsi)
 {
 	int err = -1;
 	char *line = NULL;
 	size_t n;
-	FILE *from_fp = fopen(from, "r"), *to_fp;
+	FILE *from_fp, *to_fp;
+	struct nscookie nsc;
 
+	nsinfo__mountns_enter(nsi, &nsc);
+	from_fp = fopen(from, "r");
+	nsinfo__mountns_exit(&nsc);
 	if (from_fp == NULL)
 		goto out;
 
@@ -198,15 +202,21 @@ int copyfile_offset(int ifd, loff_t off_in, int ofd, loff_t off_out, u64 size)
 	return size ? -1 : 0;
 }
 
-int copyfile_mode(const char *from, const char *to, mode_t mode)
+static int copyfile_mode_ns(const char *from, const char *to, mode_t mode,
+			    struct nsinfo *nsi)
 {
 	int fromfd, tofd;
 	struct stat st;
-	int err = -1;
+	int err;
 	char *tmp = NULL, *ptr = NULL;
+	struct nscookie nsc;
 
-	if (stat(from, &st))
+	nsinfo__mountns_enter(nsi, &nsc);
+	err = stat(from, &st);
+	nsinfo__mountns_exit(&nsc);
+	if (err)
 		goto out;
+	err = -1;
 
 	/* extra 'x' at the end is to reserve space for '.' */
 	if (asprintf(&tmp, "%s.XXXXXXx", to) < 0) {
@@ -227,11 +237,13 @@ int copyfile_mode(const char *from, const char *to, mode_t mode)
 		goto out_close_to;
 
 	if (st.st_size == 0) { /* /proc? do it slowly... */
-		err = slow_copyfile(from, tmp);
+		err = slow_copyfile(from, tmp, nsi);
 		goto out_close_to;
 	}
 
+	nsinfo__mountns_enter(nsi, &nsc);
 	fromfd = open(from, O_RDONLY);
+	nsinfo__mountns_exit(&nsc);
 	if (fromfd < 0)
 		goto out_close_to;
 
@@ -248,6 +260,16 @@ out:
 	return err;
 }
 
+int copyfile_ns(const char *from, const char *to, struct nsinfo *nsi)
+{
+	return copyfile_mode_ns(from, to, 0755, nsi);
+}
+
+int copyfile_mode(const char *from, const char *to, mode_t mode)
+{
+	return copyfile_mode_ns(from, to, mode, NULL);
+}
+
 int copyfile(const char *from, const char *to)
 {
 	return copyfile_mode(from, to, 0755);