setpriv: dump capability bounding set

As with the previous commit, this one implements the ability to dump the
capability bounding set.

function                                             old     new   delta
setpriv_main                                         838     982    +144
.rodata                                           146101  146148     +47

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 23 insertions, 0 deletions

diff --git a/util-linux/setpriv.c b/util-linux/setpriv.c
index a509204a2..c3f9ea153 100644
--- a/util-linux/setpriv.c
+++ b/util-linux/setpriv.c
@@ -82,6 +82,10 @@
 #include <sys/prctl.h>
 #include "libbb.h"
 
+#ifndef PR_CAPBSET_READ
+#define PR_CAPBSET_READ 23
+#endif
+
 #ifndef PR_SET_NO_NEW_PRIVS
 #define PR_SET_NO_NEW_PRIVS 38
 #endif
@@ -247,6 +251,25 @@ static int dump(void)
         }
         if (!fmt[0])
                 printf("[none]");
+
+        printf("\nCapability bounding set: ");
+        fmt = "";
+        for (i = 0; cap_valid(i); i++) {
+                int ret = prctl(PR_CAPBSET_READ, (unsigned long) i, 0UL, 0UL, 0UL);
+                if (ret < 0)
+                        bb_simple_perror_msg_and_die("prctl: CAPBSET_READ");
+                if (ret) {
+#  if ENABLE_FEATURE_SETPRIV_CAPABILITY_NAMES
+                        if (i < ARRAY_SIZE(capabilities))
+                                printf("%s%s", fmt, capabilities[i]);
+                        else
+#  endif
+                                printf("%scap_%u", fmt, i);
+                        fmt = ",";
+                }
+        }
+        if (!fmt[0])
+                printf("[none]");
         bb_putchar('\n');
 # endif