[PATCH] ld.so: Decorate BSS mappings

[Petr Malat]

Decorate BSS mappings with [anon: .bss <file>], for example
[anon: .bss /lib/libc.so.6]. The string ".bss" is already used
by bionic so use the same, but add the filename as well.

Signed-off-by: Petr Malat <oss@malat.biz>
---
 elf/dl-map-segments.h | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/elf/dl-map-segments.h b/elf/dl-map-segments.h
index 203b6c7b0b..cf6be4a783 100644
--- a/elf/dl-map-segments.h
+++ b/elf/dl-map-segments.h
@@ -18,6 +18,7 @@
    <https://www.gnu.org/licenses/>.  */
 
 #include <dl-load.h>
+#include <setvmaname.h>
 
 /* Map a segment and align it properly.  */
 
@@ -182,12 +183,31 @@ _dl_map_segments (struct link_map *l, int fd,
           if (zeroend > zeropage)
             {
               /* Map the remaining zero pages in from the zero fill FD.  */
+              char bssname[80] = " .bss";
+
               caddr_t mapat;
               mapat = __mmap ((caddr_t) zeropage, zeroend - zeropage,
                               c->prot, MAP_ANON|MAP_PRIVATE|MAP_FIXED,
                               -1, 0);
               if (__glibc_unlikely (mapat == MAP_FAILED))
                 return DL_MAP_SEGMENTS_ERROR_MAP_ZERO_FILL;
+              if (l->l_name && *l->l_name)
+                {
+                  int i = strlen(bssname), j = 0;
+                  bssname[i++] = ' ';
+                  if (strlen(l->l_name) > sizeof(bssname) - i - 1)
+                    j = strlen(l->l_name) - (sizeof(bssname) - i - 1);
+                  for (; l->l_name[j]; i++, j++)
+                    {
+                      char ch = l->l_name[j];
+                      /* Replace non-printable characters and \, `, $, [ and ] */
+                      if (ch <= 0x1f || ch >= 0x7f || strchr("\\`$[]", ch))
+                        ch = '!';
+                      bssname[i] = ch;
+                    }
+                  bssname[i] = 0;
+                }
+              __set_vma_name ((void*)zeropage, zeroend - zeropage, bssname);
             }
         }
 
-- 
2.39.5