binutils-gdb/gdb/common/common-utils.h
Sergio Durigan Junior 25e3c82c0e Make gdbserver work with filename-only binaries
Simon mentioned on IRC that, after the startup-with-shell feature has
been implemented on gdbserver, it is not possible to specify a
filename-only binary, like:

  $ gdbserver :1234 a.out
  /bin/bash: line 0: exec: a.out: not found
  During startup program exited with code 127.
  Exiting

This happens on systems where the current directory "." is not listed
in the PATH environment variable.  Although including "." in the PATH
variable is a possible workaround, this can be considered a regression
because before startup-with-shell it was possible to use only the
filename (due to reason that gdbserver used "exec*" directly).

The idea of the patch is to verify if the program path provided by the
user (or by the remote protocol) contains a directory separator
character.  If it doesn't, it means we're dealing with a filename-only
binary, so we call "gdb_abspath" to properly expand it and transform
it into a full path.  Otherwise, we leave the program path untouched.
This mimicks the behaviour seen on GDB (look at "openp" and
"attach_inferior", for example).

I am also submitting a testcase which exercises the scenario described
above.  This test requires gdbserver to be executed in a different CWD
than the original, so I also created a helper function, "with_cwd" (on
testsuite/lib/gdb.exp), which takes care of cd'ing into and out of the
specified dir.

Built and regtested on BuildBot, without regressions.

gdb/ChangeLog:
2018-02-28  Sergio Durigan Junior  <sergiodj@redhat.com>
	    Simon Marchi  <simon.marchi@polymtl.ca>

	* common/common-utils.c: Include "sys/stat.h".
	(is_regular_file): Move here from "source.c"; change return
	type to "bool".
	* common/common-utils.h (is_regular_file): New prototype.
	* common/pathstuff.c (contains_dir_separator): New function.
	* common/pathstuff.h (contains_dir_separator): New prototype.
	* source.c: Don't include "sys/stat.h".
	(is_regular_file): Move to "common/common-utils.c".

gdb/gdbserver/ChangeLog:
2018-02-28  Sergio Durigan Junior  <sergiodj@redhat.com>

	* server.c: Include "filenames.h" and "pathstuff.h".
	(program_name): Delete variable.
	(program_path): New anonymous class.
	(get_exec_wrapper): Use "program_path" instead of
	"program_name".
	(handle_v_run): Likewise.
	(captured_main): Likewise.
	(process_serial_event): Likewise.

gdb/testsuite/ChangeLog:
2018-02-28  Sergio Durigan Junior  <sergiodj@redhat.com>

	* gdb.server/abspath.exp: New file.
	* lib/gdb.exp (with_cwd): New procedure.
2018-02-28 11:37:10 -05:00

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C++

/* Shared general utility routines for GDB, the GNU debugger.
Copyright (C) 1986-2018 Free Software Foundation, Inc.
This file is part of GDB.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program 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 General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>. */
#ifndef COMMON_UTILS_H
#define COMMON_UTILS_H
#include <string>
#include <vector>
#include "poison.h"
/* If possible, define FUNCTION_NAME, a macro containing the name of
the function being defined. Since this macro may not always be
defined, all uses must be protected by appropriate macro definition
checks (Eg: "#ifdef FUNCTION_NAME").
Version 2.4 and later of GCC define a magical variable `__PRETTY_FUNCTION__'
which contains the name of the function currently being defined.
This is broken in G++ before version 2.6.
C9x has a similar variable called __func__, but prefer the GCC one since
it demangles C++ function names. */
#if (GCC_VERSION >= 2004)
#define FUNCTION_NAME __PRETTY_FUNCTION__
#else
#if defined __STDC_VERSION__ && __STDC_VERSION__ >= 199901L
#define FUNCTION_NAME __func__ /* ARI: func */
#endif
#endif
/* xmalloc(), xrealloc() and xcalloc() have already been declared in
"libiberty.h". */
/* Like xmalloc, but zero the memory. */
void *xzalloc (size_t);
template <typename T>
static void
xfree (T *ptr)
{
static_assert (IsFreeable<T>::value, "Trying to use xfree with a non-POD \
data type. Use operator delete instead.");
if (ptr != NULL)
free (ptr); /* ARI: free */
}
/* Like asprintf and vasprintf, but return the string, throw an error
if no memory. */
char *xstrprintf (const char *format, ...) ATTRIBUTE_PRINTF (1, 2);
char *xstrvprintf (const char *format, va_list ap)
ATTRIBUTE_PRINTF (1, 0);
/* Like snprintf, but throw an error if the output buffer is too small. */
int xsnprintf (char *str, size_t size, const char *format, ...)
ATTRIBUTE_PRINTF (3, 4);
/* Returns a std::string built from a printf-style format string. */
std::string string_printf (const char* fmt, ...)
ATTRIBUTE_PRINTF (1, 2);
/* Like string_printf, but takes a va_list. */
std::string string_vprintf (const char* fmt, va_list args)
ATTRIBUTE_PRINTF (1, 0);
/* Like string_printf, but appends to DEST instead of returning a new
std::string. */
void string_appendf (std::string &dest, const char* fmt, ...)
ATTRIBUTE_PRINTF (2, 3);
/* Like string_appendf, but takes a va_list. */
void string_vappendf (std::string &dest, const char* fmt, va_list args)
ATTRIBUTE_PRINTF (2, 0);
/* Make a copy of the string at PTR with LEN characters
(and add a null character at the end in the copy).
Uses malloc to get the space. Returns the address of the copy. */
char *savestring (const char *ptr, size_t len);
/* The strerror() function can return NULL for errno values that are
out of range. Provide a "safe" version that always returns a
printable string. */
extern char *safe_strerror (int);
/* Return non-zero if the start of STRING matches PATTERN, zero
otherwise. */
static inline int
startswith (const char *string, const char *pattern)
{
return strncmp (string, pattern, strlen (pattern)) == 0;
}
ULONGEST strtoulst (const char *num, const char **trailer, int base);
/* Skip leading whitespace characters in INP, returning an updated
pointer. If INP is NULL, return NULL. */
extern char *skip_spaces (char *inp);
/* A const-correct version of the above. */
extern const char *skip_spaces (const char *inp);
/* Skip leading non-whitespace characters in INP, returning an updated
pointer. If INP is NULL, return NULL. */
extern char *skip_to_space (char *inp);
/* A const-correct version of the above. */
extern const char *skip_to_space (const char *inp);
/* Assumes that V is an argv for a program, and iterates through
freeing all the elements. */
extern void free_vector_argv (std::vector<char *> &v);
/* Given a vector of arguments ARGV, return a string equivalent to
joining all the arguments with a whitespace separating them. */
extern std::string stringify_argv (const std::vector<char *> &argv);
/* Return true if VALUE is in [LOW, HIGH]. */
template <typename T>
static bool
in_inclusive_range (T value, T low, T high)
{
return value >= low && value <= high;
}
/* Return true if the file NAME exists and is a regular file.
If the result is false then *ERRNO_PTR is set to a useful value assuming
we're expecting a regular file. */
extern bool is_regular_file (const char *name, int *errno_ptr);
#endif