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C++ify gdb/common/environ.c

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As part of the preparation necessary for my upcoming task, I'd like to
propose that we turn gdb_environ into a class.  The approach taken
here is simple: the class gdb_environ contains everything that is
needed to manipulate the environment variables.  These variables are
stored in an std::vector<char *>, which can be converted to a 'char
**' and passed as argument to functions that need it.

The usage has not changed much.  As per Pedro's suggestion, this class
uses a static factory method initialization.  This means that when an
instance is created, it is initially empty.  When needed, it has to be
initialized using the static method 'from_host_environ'.

As mentioned before, this is a preparation for an upcoming work that I
will be posting in the next few weeks or so.  For that work, I'll
probably create another data structure that will contain all the
environment variables that were set by the user using the 'set
environment' command, because I'll need access to them.  This will be
much easier with the class-ification of gdb_environ.

As noted, this has been regression-tested with the new version of
environ.exp and no regressions were found.

gdb/ChangeLog:
2017-06-20  Sergio Durigan Junior  <sergiodj@redhat.com>

	* Makefile.in (SUBDIR_UNITTESTS_SRCS): Add
	'unittests/environ-selftests.c'.
	(SUBDIR_UNITTESTS_OBS): Add 'environ-selftests.o'.
	* charset.c (find_charset_names): Declare object 'iconv_env'.
	Update code to use 'iconv_env' object.  Remove call to
	'free_environ'.
	* common/environ.c: Include <utility>.
	(make_environ): Delete function.
	(free_environ): Delete function.
	(gdb_environ::clear): New function.
	(gdb_environ::operator=): New function.
	(gdb_environ::get): Likewise.
	(environ_vector): Delete function.
	(set_in_environ): Delete function.
	(gdb_environ::set): New function.
	(unset_in_environ): Delete function.
	(gdb_environ::unset): New function.
	(gdb_environ::envp): Likewise.
	* common/environ.h: Include <vector>.
	(struct gdb_environ): Delete; transform into...
	(class gdb_environ): ... this class.
	(free_environ): Delete prototype.
	(init_environ, get_in_environ, set_in_environ, unset_in_environ,
	environ_vector): Likewise.
	* infcmd.c (run_command_1): Update code to call
	'envp' from 'gdb_environ' class.
	(environment_info): Update code to call methods from 'gdb_environ'
	class.
	(unset_environment_command): Likewise.
	(path_info): Likewise.
	(path_command): Likewise.
	* inferior.c (inferior::~inferior): Delete call to 'free_environ'.
	(inferior::inferior): Initialize 'environment' using the host's
	information.
	* inferior.h: Remove forward declaration of 'struct gdb_environ'.
	Include "environ.h".
	(class inferior) <environment>: Change type from 'struct
	gdb_environ' to 'gdb_environ'.
	* mi/mi-cmd-env.c (mi_cmd_env_path): Update code to call
	methods from 'gdb_environ' class.
	* solib.c (solib_find_1): Likewise
	* unittests/environ-selftests.c: New file.

gdb/gdbserver/ChangeLog:
2017-06-20  Sergio Durigan Junior  <sergiodj@redhat.com>

	* linux-low.c (linux_create_inferior): Adjust code to access the
	environment information via 'gdb_environ' class.
	* lynx-low.c (lynx_create_inferior): Likewise.
	* server.c (our_environ): Make it an instance of 'gdb_environ'.
	(get_environ): Return a pointer to 'our_environ'.
	(captured_main): Initialize 'our_environ'.
	* server.h (get_environ): Adjust prototype.
	* spu-low.c (spu_create_inferior): Adjust code to access the
	environment information via 'gdb_environ' class.
This commit is contained in:
Sergio Durigan Junior
2017-02-10 21:19:44 -05:00
parent 75c554cf9c
commit 9a6c7d9c02
17 changed files with 391 additions and 204 deletions
Download Patch File Download Diff File Expand all files Collapse all files

232
gdb/common/environ.c
View File

@@ -18,165 +18,119 @@
#include "common-defs.h"
#include "environ.h"
#include <algorithm>
#include <utility>
/* Return a new environment object. */
/* See common/environ.h. */
struct gdb_environ *
make_environ (void)
gdb_environ &
gdb_environ::operator= (gdb_environ &&e)
{
struct gdb_environ *e;
/* Are we self-moving? */
if (&e == this)
return *this;
e = XNEW (struct gdb_environ);
m_environ_vector = std::move (e.m_environ_vector);
e.m_environ_vector.clear ();
e.m_environ_vector.push_back (NULL);
return *this;
}
/* See common/environ.h. */
gdb_environ gdb_environ::from_host_environ ()
{
extern char **environ;
gdb_environ e;
if (environ == NULL)
return e;
for (int i = 0; environ[i] != NULL; ++i)
{
/* Make sure we add the element before the last (NULL). */
e.m_environ_vector.insert (e.m_environ_vector.end () - 1,
xstrdup (environ[i]));
}
e->allocated = 10;
e->vector = (char **) xmalloc ((e->allocated + 1) * sizeof (char *));
e->vector[0] = 0;
return e;
}
/* Free an environment and all the strings in it. */
/* See common/environ.h. */
void
free_environ (struct gdb_environ *e)
gdb_environ::clear ()
{
char **vector = e->vector;
while (*vector)
xfree (*vector++);
xfree (e->vector);
xfree (e);
for (char *v : m_environ_vector)
xfree (v);
m_environ_vector.clear ();
/* Always add the NULL element. */
m_environ_vector.push_back (NULL);
}
/* Copy the environment given to this process into E.
Also copies all the strings in it, so we can be sure
that all strings in these environments are safe to free. */
/* Helper function to check if STRING contains an environment variable
assignment of VAR, i.e., if STRING starts with 'VAR='. Return true
if it contains, false otherwise. */
static bool
match_var_in_string (char *string, const char *var, size_t var_len)
{
if (strncmp (string, var, var_len) == 0 && string[var_len] == '=')
return true;
return false;
}
/* See common/environ.h. */
const char *
gdb_environ::get (const char *var) const
{
size_t len = strlen (var);
for (char *el : m_environ_vector)
if (el != NULL && match_var_in_string (el, var, len))
return &el[len + 1];
return NULL;
}
/* See common/environ.h. */
void
init_environ (struct gdb_environ *e)
gdb_environ::set (const char *var, const char *value)
{
extern char **environ;
int i;
/* We have to unset the variable in the vector if it exists. */
unset (var);
if (environ == NULL)
return;
for (i = 0; environ[i]; i++) /*EMPTY */ ;
if (e->allocated < i)
{
e->allocated = std::max (i, e->allocated + 10);
e->vector = (char **) xrealloc ((char *) e->vector,
(e->allocated + 1) * sizeof (char *));
}
memcpy (e->vector, environ, (i + 1) * sizeof (char *));
while (--i >= 0)
{
int len = strlen (e->vector[i]);
char *newobj = (char *) xmalloc (len + 1);
memcpy (newobj, e->vector[i], len + 1);
e->vector[i] = newobj;
}
/* Insert the element before the last one, which is always NULL. */
m_environ_vector.insert (m_environ_vector.end () - 1,
concat (var, "=", value, NULL));
}
/* Return the vector of environment E.
This is used to get something to pass to execve. */
/* See common/environ.h. */
void
gdb_environ::unset (const char *var)
{
size_t len = strlen (var);
/* We iterate until '.cend () - 1' because the last element is
always NULL. */
for (std::vector<char *>::const_iterator el = m_environ_vector.cbegin ();
el != m_environ_vector.cend () - 1;
++el)
if (match_var_in_string (*el, var, len))
{
xfree (*el);
m_environ_vector.erase (el);
break;
}
}
/* See common/environ.h. */
char **
environ_vector (struct gdb_environ *e)
gdb_environ::envp () const
{
return e->vector;
}
/* Return the value in environment E of variable VAR. */
char *
get_in_environ (const struct gdb_environ *e, const char *var)
{
int len = strlen (var);
char **vector = e->vector;
char *s;
for (; (s = *vector) != NULL; vector++)
if (strncmp (s, var, len) == 0 && s[len] == '=')
return &s[len + 1];
return 0;
}
/* Store the value in E of VAR as VALUE. */
void
set_in_environ (struct gdb_environ *e, const char *var, const char *value)
{
int i;
int len = strlen (var);
char **vector = e->vector;
char *s;
for (i = 0; (s = vector[i]) != NULL; i++)
if (strncmp (s, var, len) == 0 && s[len] == '=')
break;
if (s == 0)
{
if (i == e->allocated)
{
e->allocated += 10;
vector = (char **) xrealloc ((char *) vector,
(e->allocated + 1) * sizeof (char *));
e->vector = vector;
}
vector[i + 1] = 0;
}
else
xfree (s);
s = (char *) xmalloc (len + strlen (value) + 2);
strcpy (s, var);
strcat (s, "=");
strcat (s, value);
vector[i] = s;
/* This used to handle setting the PATH and GNUTARGET variables
specially. The latter has been replaced by "set gnutarget"
(which has worked since GDB 4.11). The former affects searching
the PATH to find SHELL, and searching the PATH to find the
argument of "symbol-file" or "exec-file". Maybe we should have
some kind of "set exec-path" for that. But in any event, having
"set env" affect anything besides the inferior is a bad idea.
What if we want to change the environment we pass to the program
without afecting GDB's behavior? */
return;
}
/* Remove the setting for variable VAR from environment E. */
void
unset_in_environ (struct gdb_environ *e, const char *var)
{
int len = strlen (var);
char **vector = e->vector;
char *s;
for (; (s = *vector) != NULL; vector++)
{
if (strncmp (s, var, len) == 0 && s[len] == '=')
{
xfree (s);
/* Walk through the vector, shuffling args down by one, including
the NULL terminator. Can't use memcpy() here since the regions
overlap, and memmove() might not be available. */
while ((vector[0] = vector[1]) != NULL)
{
vector++;
}
break;
}
}
return const_cast<char **> (&m_environ_vector[0]);
}