Add pldd program

ChangeLog

@@ -1,3 +1,9 @@
+2011-06-09  Ulrich Drepper  <drepper@gmail.com>
+
+	* elf/Makefile: Add rules to build pldd.
+	* elf/pldd.c: New file.
+	* elf/pldd-xx.c: New file.
+
 2011-06-07  Ulrich Drepper  <drepper@gmail.com>
 
 	* version.h: Update for 2.15 development version.

NEWS

@@ -1,4 +1,4 @@
-GNU C Library NEWS -- history of user-visible changes.  2011-6-7
+GNU C Library NEWS -- history of user-visible changes.  2011-6-9
 Copyright (C) 1992-2009, 2010, 2011 Free Software Foundation, Inc.
 See the end for copying conditions.
 
@@ -6,6 +6,9 @@ Please send GNU C library bug reports via <http://sources.redhat.com/bugzilla/>
 using `glibc' in the "product" field.
 
 Version 2.15
+
+* New program pldd to list loaded object of a process
+  Implemented by Ulrich Drepper.
 
 Version 2.14
 

elf/Makefile

@@ -150,8 +150,8 @@ install-others	= $(inst_slibdir)/$(rtld-installed-name)
 install-bin-script = ldd
 endif
 
-others		= sprof sln
+others		= sprof sln pldd
-install-bin	= sprof
+install-bin	= sprof pldd
 others-static   = sln
 install-rootsbin = sln
 
@@ -164,6 +164,8 @@ install-rootsbin += ldconfig
 ldconfig-modules := cache readlib xmalloc xstrdup chroot_canon
 extra-objs	+= $(ldconfig-modules:=.o)
 
+pldd-modules := xmalloc
+
 # To find xmalloc.c and xstrdup.c
 vpath %.c ../locale/programs
 
@@ -494,6 +496,9 @@ $(objpfx)ldd: ldd.bash.in $(common-objpfx)soversions.mk \
 $(objpfx)sprof: $(libdl)
 
 $(objpfx)ldconfig: $(ldconfig-modules:%=$(objpfx)%.o)
+
+$(objpfx)pldd: $(pldd-modules:%=$(objpfx)%.o)
+
 SYSCONF-FLAGS := -D'SYSCONFDIR="$(sysconfdir)"'
 CFLAGS-ldconfig.c = $(SYSCONF-FLAGS) -D'LIBDIR="$(libdir)"' \
 		    -D'SLIBDIR="$(slibdir)"' -DIS_IN_ldconfig=1

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

elf/pldd.c

@@ -0,0 +1,234 @@
+/* List dynamic shared objects linked into given process.
+   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.  */
+
+#include <alloca.h>
+#include <argp.h>
+#include <elf.h>
+#include <errno.h>
+#include <error.h>
+#include <fcntl.h>
+#include <libintl.h>
+#include <link.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/ptrace.h>
+#include <sys/stat.h>
+
+#include <ldsodefs.h>
+#include <version.h>
+
+/* Global variables.  */
+extern char *program_invocation_short_name;
+#define PACKAGE _libc_intl_domainname
+
+/* External functions.  */
+extern void *xmalloc (size_t n);
+extern void *xrealloc (void *p, size_t n);
+
+/* Name and version of program.  */
+static void print_version (FILE *stream, struct argp_state *state);
+void (*argp_program_version_hook) (FILE *, struct argp_state *) = print_version;
+
+/* Bug report address.  */
+const char *argp_program_bug_address = N_("\
+For bug reporting instructions, please see:\n\
+<http://www.gnu.org/software/libc/bugs.html>.\n");
+
+/* Definitions of arguments for argp functions.  */
+static const struct argp_option options[] =
+{
+  { NULL, 0, NULL, 0, NULL }
+};
+
+/* Short description of program.  */
+static const char doc[] = N_("\
+List dynamic shared objects loaded into process.");
+
+/* Strings for arguments in help texts.  */
+static const char args_doc[] = N_("PID");
+
+/* Prototype for option handler.  */
+static error_t parse_opt (int key, char *arg, struct argp_state *state);
+
+/* Data structure to communicate with argp functions.  */
+static struct argp argp =
+{
+  options, parse_opt, args_doc, doc, NULL, NULL, NULL
+};
+
+// File descriptor of /proc/*/mem file.
+static int memfd;
+
+/* Name of the executable  */
+static char *exe;
+
+/* Local functions.  */
+static int get_process_info (pid_t pid);
+
+
+int
+main (int argc, char *argv[])
+{
+  /* Parse and process arguments.  */
+  int remaining;
+  argp_parse (&argp, argc, argv, 0, &remaining, NULL);
+
+  if (remaining != argc - 1)
+    {
+      fprintf (stderr,
+	       gettext ("Exactly one parameter with process ID required.\n"));
+      argp_help (&argp, stderr, ARGP_HELP_SEE, program_invocation_short_name);
+      return 1;
+    }
+
+  char *endp;
+  errno = 0;
+  pid_t pid = strtoul (argv[remaining], &endp, 10);
+  if ((pid == ULONG_MAX && errno == ERANGE) || *endp != '\0')
+    error (EXIT_FAILURE, 0, gettext ("invalid process ID '%s'"),
+	   argv[remaining]);
+
+  /* Determine the program name.  */
+  char buf[11 + 3 * sizeof (pid)];
+  snprintf (buf, sizeof (buf), "/proc/%lu/exe", (unsigned long int) pid);
+  size_t exesize = 1024;
+  exe = alloca (exesize);
+  ssize_t nexe;
+  while ((nexe = readlink (buf, exe, exesize)) == exesize)
+    extend_alloca (exe, exesize, 2 * exesize);
+  if (nexe == -1)
+    exe = (char *) "<program name undetermined>";
+  else
+    exe[nexe] = '\0';
+
+  if (ptrace (PTRACE_ATTACH, pid, NULL, NULL) != 0)
+    error (EXIT_FAILURE, errno, gettext ("cannot attach to process %lu"),
+	   (unsigned long int) pid);
+
+  int status = get_process_info (pid);
+
+  ptrace (PTRACE_DETACH, pid, NULL, NULL);
+
+  return status;
+}
+
+
+/* Handle program arguments.  */
+static error_t
+parse_opt (int key, char *arg, struct argp_state *state)
+{
+  switch (key)
+    {
+    default:
+      return ARGP_ERR_UNKNOWN;
+    }
+  return 0;
+}
+
+
+/* Print the version information.  */
+static void
+print_version (FILE *stream, struct argp_state *state)
+{
+  fprintf (stream, "pldd (GNU %s) %s\n", PACKAGE, VERSION);
+  fprintf (stream, gettext ("\
+Copyright (C) %s Free Software Foundation, Inc.\n\
+This is free software; see the source for copying conditions.  There is NO\n\
+warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.\n\
+"), "2011");
+  fprintf (stream, gettext ("Written by %s.\n"), "Ulrich Drepper");
+}
+
+
+#define CLASS 32
+#include "pldd-xx.c"
+#define CLASS 64
+#include "pldd-xx.c"
+
+
+static int
+get_process_info (pid_t pid)
+{
+  char buf[12 + 3 * sizeof (pid)];
+
+  snprintf (buf, sizeof (buf), "/proc/%lu/mem", (unsigned long int) pid);
+  memfd = open (buf, O_RDONLY);
+  if (memfd == -1)
+    goto no_info;
+
+  snprintf (buf, sizeof (buf), "/proc/%lu/exe", (unsigned long int) pid);
+  int fd = open (buf, O_RDONLY);
+  if (fd == -1)
+    {
+    no_info:
+      error (0, errno, gettext ("cannot get information about process %lu"),
+	     (unsigned long int) pid);
+      return EXIT_FAILURE;
+    }
+
+  union
+  {
+    Elf32_Ehdr ehdr32;
+    Elf64_Ehdr ehdr64;
+  } uehdr;
+  if (read (fd, &uehdr, sizeof (uehdr)) != sizeof (uehdr))
+    goto no_info;
+
+  close (fd);
+
+  if (memcmp (uehdr.ehdr32.e_ident, ELFMAG, SELFMAG) != 0)
+    {
+      error (0, 0, gettext ("process %lu is no ELF program"),
+	     (unsigned long int) pid);
+      return EXIT_FAILURE;
+    }
+
+  snprintf (buf, sizeof (buf), "/proc/%lu/auxv", (unsigned long int) pid);
+  fd = open (buf, O_RDONLY);
+  if (fd == -1)
+    goto no_info;
+
+  size_t auxv_size = 0;
+  void *auxv = NULL;
+  while (1)
+    {
+      auxv_size += 512;
+      auxv = xrealloc (auxv, auxv_size);
+
+      ssize_t n = read (fd, auxv, auxv_size);
+      if (n < 0)
+	goto no_info;
+      if (n < auxv_size)
+	{
+	  auxv_size = n;
+	  break;
+	}
+    }
+
+  close (fd);
+
+  if (uehdr.ehdr32.e_ident[EI_CLASS] == ELFCLASS32)
+    return find_maps32 (pid, &uehdr.ehdr32, auxv, auxv_size);
+  else
+    return find_maps64 (pid, &uehdr.ehdr64, auxv, auxv_size);
+}