/* Trace calls through PLTs and show caller, callee, and parameters.

   Copyright (C) 2011-2018 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, see

   <http://www.gnu.org/licenses/>.  */

#include <error.h>

#include <fcntl.h>

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <unistd.h>

#include <sys/param.h>

#include <sys/uio.h>

#include <ldsodefs.h>

extern const char *__progname;

extern const char *__progname_full;

/* List of objects to trace calls from.  */

static const char *fromlist;

/* List of objects to trace calls to.  */

static const char *tolist;

/* If non-zero, also trace returns of the calls.  */

static int do_exit;

/* If non-zero print PID for each line.  */

static int print_pid;

/* The output stream to use.  */

static FILE *out_file;

static int

match_pid (pid_t pid, const char *which)

{

  if (which == NULL || which[0] == '\0')

    {

      print_pid = 1;

      return 1;

    }

  char *endp;

  unsigned long n = strtoul (which, &endp, 0);

  return *endp == '\0' && n == pid;

}

static void

init (void)

{

  fromlist = getenv ("SOTRUSS_FROMLIST");

  if (fromlist != NULL && fromlist[0] == '\0')

    fromlist = NULL;

  tolist = getenv ("SOTRUSS_TOLIST");

  if (tolist != NULL && tolist[0] == '\0')

    tolist = NULL;

  do_exit = (getenv ("SOTRUSS_EXIT") ?: "")[0] != '\0';

  /* Determine whether this process is supposed to be traced and if

     yes, whether we should print into a file.  */

  const char *which_process = getenv ("SOTRUSS_WHICH");

  pid_t pid = getpid ();

  int out_fd = -1;

  if (match_pid (pid, which_process))

    {

      const char *out_filename = getenv ("SOTRUSS_OUTNAME");

      if (out_filename != NULL && out_filename[0] != 0)

	{

	  size_t out_filename_len = strlen (out_filename) + 13;

	  char fullname[out_filename_len];

	  char *endp = stpcpy (fullname, out_filename);

	  if (which_process == NULL || which_process[0] == '\0')

	    snprintf (endp, 13, ".%ld", (long int) pid);

	  out_fd = open (fullname, O_RDWR | O_CREAT | O_TRUNC, 0666);

	  if (out_fd != -1)

	    print_pid = 0;

	}

    }

  /* If we do not write into a file write to stderr.  Duplicate the

     descriptor so that we can keep printing in case the program

     closes stderr.  Try first to allocate a descriptor with a value

     usually not used as to minimize interference with the

     program.  */

  if (out_fd == -1)

    {

      out_fd = fcntl (STDERR_FILENO, F_DUPFD, 1000);

      if (out_fd == -1)

	out_fd = dup (STDERR_FILENO);

    }

  if (out_fd != -1)

    {

      /* Convert file descriptor into a stream.  */

      out_file = fdopen (out_fd, "w");

      if (out_file != NULL)

	setlinebuf (out_file);

    }

}

/* Audit interface verification.  We also initialize everything if

   everything checks out OK.  */

unsigned int

la_version (unsigned int v)

{

  if (v != LAV_CURRENT)

    error (1, 0, "cannot handle interface version %u", v);

  init ();

  return v;

}

/* Check whether a file name is on the colon-separated list of file

   names.  */

static unsigned int

match_file (const char *list, const char *name, size_t name_len,

	    unsigned int mask)

{

  if (list[0] == '\0')

    return 0;

  const char *cp = list;

  while (1)

    {

      if (strncmp (cp, name, name_len) == 0

	  && (cp[name_len] == ':' || cp[name_len] == '\0'))

	return mask;

      cp = strchr (cp, ':');

      if (cp == NULL)

	return 0;

      ++cp;

    }

}

unsigned int

la_objopen (struct link_map *map, Lmid_t lmid, uintptr_t *cookie)

{

  if (out_file == NULL)

    return 0;

  const char *full_name = map->l_name ?: "";

  if (full_name[0] == '\0')

    full_name = __progname_full;

  size_t full_name_len = strlen (full_name);

  const char *base_name = basename (full_name);

  if (base_name[0] == '\0')

    base_name = __progname;

  size_t base_name_len = strlen (base_name);

  int result = 0;

  const char *print_name = NULL;

  for (struct libname_list *l = map->l_libname; l != NULL; l = l->next)

    {

      if (print_name == NULL || (print_name[0] == '/' && l->name[0] != '/'))

	print_name = l->name;

      if (fromlist != NULL)

	result |= match_file (fromlist, l->name, strlen (l->name),

			      LA_FLG_BINDFROM);

      if (tolist != NULL)

	result |= match_file (tolist, l->name, strlen (l->name),LA_FLG_BINDTO);

    }

  if (print_name == NULL)

    print_name = base_name;

  if (print_name[0] == '\0')

    print_name = __progname;

  /* We cannot easily get to the object name in the PLT handling

     functions.  Use the cookie to get the string pointer passed back

     to us.  */

  *cookie = (uintptr_t) print_name;

  /* The object name has to be on the list of objects to trace calls

     from or that list must be empty.  In the latter case we trace

     only calls from the main binary.  */

  if (fromlist == NULL)

    result |= map->l_name[0] == '\0' ? LA_FLG_BINDFROM : 0;

  else

    result |= (match_file (fromlist, full_name, full_name_len,

			   LA_FLG_BINDFROM)

	       | match_file (fromlist, base_name, base_name_len,

			     LA_FLG_BINDFROM));

  /* The object name has to be on the list of objects to trace calls

     to or that list must be empty.  In the latter case we trace

     calls toall objects.  */

  if (tolist == NULL)

    result |= LA_FLG_BINDTO;

  else

    result |= (match_file (tolist, full_name, full_name_len, LA_FLG_BINDTO)

	       | match_file (tolist, base_name, base_name_len, LA_FLG_BINDTO));

  return result;

}

#if __ELF_NATIVE_CLASS == 32

# define la_symbind la_symbind32

typedef Elf32_Sym Elf_Sym;

#else

# define la_symbind la_symbind64

typedef Elf64_Sym Elf_Sym;

#endif

uintptr_t

la_symbind (Elf_Sym *sym, unsigned int ndx, uintptr_t *refcook,

	    uintptr_t *defcook, unsigned int *flags, const char *symname)

{

  if (!do_exit)

    *flags = LA_SYMB_NOPLTEXIT;

  return sym->st_value;

}

static void

print_enter (uintptr_t *refcook, uintptr_t *defcook, const char *symname,

	     unsigned long int reg1, unsigned long int reg2,

	     unsigned long int reg3, unsigned int flags)

{

  char buf[3 * sizeof (pid_t) + 3];

  buf[0] = '\0';

  if (print_pid)

    snprintf (buf, sizeof (buf), "%5ld: ", (long int) getpid ());

  fprintf (out_file, "%s%15s -> %-15s:%s%s(0x%lx, 0x%lx, 0x%lx)\n",

	   buf, (char *) *refcook, (char *) *defcook,

	   (flags & LA_SYMB_NOPLTEXIT) ? "*" : " ", symname, reg1, reg2, reg3);

}

#ifdef __i386__

Elf32_Addr

la_i86_gnu_pltenter (Elf32_Sym *sym __attribute__ ((unused)),

		     unsigned int ndx __attribute__ ((unused)),

		     uintptr_t *refcook, uintptr_t *defcook,

		     La_i86_regs *regs, unsigned int *flags,

		     const char *symname, long int *framesizep)

{

  unsigned long int *sp = (unsigned long int *) regs->lr_esp;

  print_enter (refcook, defcook, symname, sp[1], sp[2], sp[3], *flags);

  /* No need to copy anything, we will not need the parameters in any case.  */

  *framesizep = 0;

  return sym->st_value;

}

#elif defined __x86_64__

Elf64_Addr

la_x86_64_gnu_pltenter (Elf64_Sym *sym __attribute__ ((unused)),

			unsigned int ndx __attribute__ ((unused)),

			uintptr_t *refcook, uintptr_t *defcook,

			La_x86_64_regs *regs, unsigned int *flags,

			const char *symname, long int *framesizep)

{

  print_enter (refcook, defcook, symname,

	       regs->lr_rdi, regs->lr_rsi, regs->lr_rdx, *flags);

  /* No need to copy anything, we will not need the parameters in any case.  */

  *framesizep = 0;

  return sym->st_value;

}

#elif defined __sparc__ && !defined __arch64__

Elf32_Addr

la_sparc32_gnu_pltenter (Elf32_Sym *sym __attribute__ ((unused)),

			 unsigned int ndx __attribute__ ((unused)),

			 uintptr_t *refcook, uintptr_t *defcook,

			 La_sparc32_regs *regs, unsigned int *flags,

			 const char *symname, long int *framesizep)

{

  print_enter (refcook, defcook, symname,

	       regs->lr_reg[0], regs->lr_reg[1], regs->lr_reg[2],

	       *flags);

  /* No need to copy anything, we will not need the parameters in any case.  */

  *framesizep = 0;

  return sym->st_value;

}

#elif defined __sparc__ && defined __arch64__

Elf64_Addr

la_sparc64_gnu_pltenter (Elf64_Sym *sym __attribute__ ((unused)),

			 unsigned int ndx __attribute__ ((unused)),

			 uintptr_t *refcook, uintptr_t *defcook,

			 La_sparc64_regs *regs, unsigned int *flags,

			 const char *symname, long int *framesizep)

{

  print_enter (refcook, defcook, symname,

	       regs->lr_reg[0], regs->lr_reg[1], regs->lr_reg[2],

	       *flags);

  /* No need to copy anything, we will not need the parameters in any case.  */

  *framesizep = 0;

  return sym->st_value;

}

#elif !defined HAVE_ARCH_PLTENTER

# warning "pltenter for architecture not supported"

#endif

static void

print_exit (uintptr_t *refcook, uintptr_t *defcook, const char *symname,

	    unsigned long int reg)

{

  char buf[3 * sizeof (pid_t) + 3];

  buf[0] = '\0';

  if (print_pid)

    snprintf (buf, sizeof (buf), "%5ld: ", (long int) getpid ());

  fprintf (out_file, "%s%15s -> %-15s:%s%s - 0x%lx\n",

	   buf, (char *) *refcook, (char *) *defcook, " ", symname, reg);

}

#ifdef __i386__

unsigned int

la_i86_gnu_pltexit (Elf32_Sym *sym, unsigned int ndx, uintptr_t *refcook,

		    uintptr_t *defcook, const struct La_i86_regs *inregs,

		    struct La_i86_retval *outregs, const char *symname)

{

  print_exit (refcook, defcook, symname, outregs->lrv_eax);

  return 0;

}

#elif defined __x86_64__

unsigned int

la_x86_64_gnu_pltexit (Elf64_Sym *sym, unsigned int ndx, uintptr_t *refcook,

		       uintptr_t *defcook, const struct La_x86_64_regs *inregs,

		       struct La_x86_64_retval *outregs, const char *symname)

{

  print_exit (refcook, defcook, symname, outregs->lrv_rax);

  return 0;

}

#elif defined __sparc__ && !defined __arch64__

unsigned int

la_sparc32_gnu_pltexit (Elf32_Sym *sym, unsigned int ndx, uintptr_t *refcook,

			uintptr_t *defcook, const struct La_sparc32_regs *inregs,

			struct La_sparc32_retval *outregs, const char *symname)

{

  print_exit (refcook, defcook, symname, outregs->lrv_reg[0]);

  return 0;

}

#elif defined __sparc__ && defined __arch64__

unsigned int

la_sparc64_gnu_pltexit (Elf64_Sym *sym, unsigned int ndx, uintptr_t *refcook,

			uintptr_t *defcook, const struct La_sparc64_regs *inregs,

			struct La_sparc64_retval *outregs, const char *symname)

{

  print_exit (refcook, defcook, symname, outregs->lrv_reg[0]);

  return 0;

}

#elif !defined HAVE_ARCH_PLTEXIT

# warning "pltexit for architecture not supported"

#endif