Add pldd program

1 files changed, 238 insertions, 0 deletions

diff --git a/elf/pldd-xx.c b/elf/pldd-xx.c
new file mode 100644
index 0000000000..0e3fcb78cc
--- /dev/null
+++ b/elf/pldd-xx.c
@@ -0,0 +1,238 @@
+/* Copyright (C) 2011 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Ulrich Drepper <drepper@gmail.com>, 2011.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, write to the Free
+   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+   02111-1307 USA.  */
+
+#define E(name) E_(name, CLASS)
+#define E_(name, cl) E__(name, cl)
+#define E__(name, cl) name##cl
+#define EW(type) EW_(Elf, CLASS, type)
+#define EW_(e, w, t) EW__(e, w, _##t)
+#define EW__(e, w, t) e##w##t
+
+#define static_assert(name, exp) \
+  typedef int __assert_##name[((exp) != 0) - 1]
+
+
+struct E(link_map)
+{
+  EW(Addr) l_addr;
+  EW(Addr) l_name;
+  EW(Addr) l_ld;
+  EW(Addr) l_next;
+  EW(Addr) l_prev;
+  EW(Addr) l_real;
+  Lmid_t l_ns;
+  EW(Addr) l_libname;
+};
+#if CLASS == __ELF_NATIVE_CLASS
+static_assert (l_addr, (offsetof (struct link_map, l_addr)
+			== offsetof (struct E(link_map), l_addr)));
+static_assert (l_name, (offsetof (struct link_map, l_name)
+			== offsetof (struct E(link_map), l_name)));
+static_assert (l_next, (offsetof (struct link_map, l_next)
+			== offsetof (struct E(link_map), l_next)));
+#endif
+
+
+struct E(libname_list)
+{
+  EW(Addr) name;
+  EW(Addr) next;
+};
+#if CLASS == __ELF_NATIVE_CLASS
+static_assert (name, (offsetof (struct libname_list, name)
+		      == offsetof (struct E(libname_list), name)));
+static_assert (next, (offsetof (struct libname_list, next)
+		      == offsetof (struct E(libname_list), next)));
+#endif
+
+struct E(r_debug)
+{
+  int r_version;
+  EW(Addr) r_map;
+};
+#if CLASS == __ELF_NATIVE_CLASS
+static_assert (r_version, (offsetof (struct r_debug, r_version)
+			   == offsetof (struct E(r_debug), r_version)));
+static_assert (r_map, (offsetof (struct r_debug, r_map)
+		       == offsetof (struct E(r_debug), r_map)));
+#endif
+
+
+static int
+E(find_maps) (pid_t pid, EW(Ehdr) *ehdr, void *auxv, size_t auxv_size)
+{
+  EW(Addr) phdr = 0;
+  unsigned int phnum = 0;
+  unsigned int phent = 0;
+
+  EW(auxv_t) *auxvXX = (EW(auxv_t) *) auxv;
+  for (int i = 0; i < auxv_size / sizeof (EW(auxv_t)); ++i)
+    switch (auxvXX[i].a_type)
+      {
+      case AT_PHDR:
+	phdr = auxvXX[i].a_un.a_val;
+	break;
+      case AT_PHNUM:
+	phnum = auxvXX[i].a_un.a_val;
+	break;
+      case AT_PHENT:
+	phent = auxvXX[i].a_un.a_val;
+	break;
+      default:
+	break;
+      }
+
+  if (phdr == 0 || phnum == 0 || phent == 0)
+    error (EXIT_FAILURE, 0, gettext ("cannot find program header of process"));
+
+  EW(Phdr) *p = alloca (phnum * phent);
+  if (pread64 (memfd, p, phnum * phent, phdr) != phnum * phent)
+    {
+      error (0, 0, gettext ("cannot read program header"));
+      return EXIT_FAILURE;
+    }
+
+  /* Determine the load offset.  We need this for interpreting the
+     other program header entries so we do this in a separate loop.
+     Fortunately it is the first time unless someone does something
+     stupid when linking the application.  */
+  EW(Addr) offset = 0;
+  for (unsigned int i = 0; i < phnum; ++i)
+    if (p[i].p_type == PT_PHDR)
+      {
+	offset = phdr - p[i].p_vaddr;
+	break;
+      }
+
+  EW(Addr) list = 0;
+  char *interp = NULL;
+  for (unsigned int i = 0; i < phnum; ++i)
+    if (p[i].p_type == PT_DYNAMIC)
+      {
+	EW(Dyn) *dyn = xmalloc (p[i].p_filesz);
+	if (pread64 (memfd, dyn, p[i].p_filesz, offset + p[i].p_vaddr)
+	    != p[i].p_filesz)
+	  {
+	    error (0, 0, gettext ("cannot read dynamic section"));
+	    return EXIT_FAILURE;
+	  }
+
+	/* Search for the DT_DEBUG entry.  */
+	for (unsigned int j = 0; j < p[i].p_filesz / sizeof (EW(Dyn)); ++j)
+	  if (dyn[j].d_tag == DT_DEBUG && dyn[j].d_un.d_ptr != 0)
+	    {
+	      struct E(r_debug) r;
+	      if (pread64 (memfd, &r, sizeof (r), dyn[j].d_un.d_ptr)
+		  != sizeof (r))
+		{
+		  error (0, 0, gettext ("cannot read r_debug"));
+		  return EXIT_FAILURE;
+		}
+
+	      if (r.r_map != 0)
+		{
+		  list = r.r_map;
+		  break;
+		}
+	    }
+
+	free (dyn);
+	break;
+      }
+    else if (p[i].p_type == PT_INTERP)
+      {
+	interp = alloca (p[i].p_filesz);
+	if (pread64 (memfd, interp, p[i].p_filesz, offset + p[i].p_vaddr)
+	    != p[i].p_filesz)
+	  {
+	    error (0, 0, gettext ("cannot read program interpreter"));
+	    return EXIT_FAILURE;
+	  }
+      }
+
+  if (list == 0)
+    {
+      if (interp == NULL)
+	{
+	  // XXX check whether the executable itself is the loader
+	  return EXIT_FAILURE;
+	}
+
+      // XXX perhaps try finding ld.so and _r_debug in it
+
+      return EXIT_FAILURE;
+    }
+
+  /* Print the PID and program name first.  */
+  printf ("%lu:\t%s\n", (unsigned long int) pid, exe);
+
+  /* Iterate over the list of objects and print the information.  */
+  size_t strsize = 256;
+  char *str = alloca (strsize);
+  do
+    {
+      struct E(link_map) m;
+      if (pread64 (memfd, &m, sizeof (m), list) != sizeof (m))
+	{
+	  error (0, 0, gettext ("cannot read link map"));
+	  return EXIT_FAILURE;
+	}
+
+      EW(Addr) name_offset = m.l_name;
+    again:
+      while (1)
+	{
+	  ssize_t n = pread64 (memfd, str, strsize, name_offset);
+	  if (n == -1)
+	    {
+	      error (0, 0, gettext ("cannot read object name"));
+	      return EXIT_FAILURE;
+	    }
+
+	  if (memchr (str, '\0', n) != NULL)
+	    break;
+
+	  str = extend_alloca (str, strsize, strsize * 2);
+	}
+
+      if (str[0] == '\0' && name_offset == m.l_name
+	  && m.l_libname != 0)
+	{
+	  /* Try the l_libname element.  */
+	  struct E(libname_list) ln;
+	  if (pread64 (memfd, &ln, sizeof (ln), m.l_libname) == sizeof (ln))
+	    {
+	      name_offset = ln.name;
+	      goto again;
+	    }
+	}
+
+      /* Skip over the executable.  */
+      if (str[0] != '\0')
+	printf ("%s\n", str);
+
+      list = m.l_next;
+    }
+  while (list != 0);
+
+  return 0;
+}
+
+
+#undef CLASS