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* posix.c (scm_convert_exec_args), dynl.c

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(scm_make_argv_from_stringlist): static procs: 1) renamed both to
	allocate_string_pointers.  2) simplified: don't reallocate the
	strings, just make an array of pointers 3) avoid memory leaks on
	error 4) let the procedure report errors in its own name.
	Consequences: 1) the procedures now assume that SCM strings are
	nul-terminated, which should always be the case.  2) Since strings
	are not reallocated, it's now possible for strings passed to
	dynamic-args-call to be mutated.
This commit is contained in:
Gary Houston 2002-06-30 19:27:18 +00:00
parent feec7802ff
commit 2ee08a2833
3 changed files with 69 additions and 84 deletions
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90
libguile/dynl.c
View file

@ -75,60 +75,6 @@ maybe_drag_in_eprintf ()
#include "libguile/lang.h"
#include "libguile/validate.h"
/* Create a new C argv array from a scheme list of strings. */
/* Dirk:FIXME:: A quite similar function is implemented in posix.c */
/* Dirk:FIXME:: In case of assertion errors, we get memory leaks */
/* Converting a list of SCM strings into a argv-style array. You must
have ints disabled for the whole lifetime of the created argv (from
before MAKE_ARGV_FROM_STRINGLIST until after
MUST_FREE_ARGV). Atleast this is was the documentation for
MAKARGVFROMSTRS says, it isn't really used that way.
This code probably belongs into strings.c
(Dirk: IMO strings.c is not the right place.) */
static char **
scm_make_argv_from_stringlist (SCM args, int *argcp, const char *subr,
int argn)
{
char **argv;
int argc;
int i;
argc = scm_ilength (args);
SCM_ASSERT (argc >= 0, args, argn, subr);
argv = (char **) scm_malloc ((argc + 1) * sizeof (char *));
for (i = 0; !SCM_NULL_OR_NIL_P (args); args = SCM_CDR (args), ++i) {
SCM arg = SCM_CAR (args);
size_t len;
char *dst;
char *src;
SCM_ASSERT (SCM_STRINGP (arg), args, argn, subr);
len = SCM_STRING_LENGTH (arg);
src = SCM_STRING_CHARS (arg);
dst = (char *) scm_malloc (len + 1);
memcpy (dst, src, len);
dst[len] = 0;
argv[i] = dst;
}
if (argcp)
*argcp = argc;
argv[argc] = 0;
return argv;
}
static void
scm_free_argv (char **argv)
{
char **av = argv;
while (*av)
free (*(av++));
free (argv);
}
/* Dispatch to the system dependent files
*
* They define some static functions. These functions are called with
@ -372,6 +318,35 @@ SCM_DEFINE (scm_dynamic_call, "dynamic-call", 2, 0, 0,
}
#undef FUNC_NAME
/* return a newly allocated array of char pointers to each of the strings
in args, with a terminating NULL pointer. */
/* Note: a similar function is defined in posix.c, but we don't necessarily
want to export it. */
static char **allocate_string_pointers (SCM args, int *num_args_return)
{
char **result;
int n_args = scm_ilength (args);
int i;
SCM_ASSERT (n_args >= 0, args, SCM_ARGn, "allocate_string_pointers");
result = (char **) scm_malloc ((n_args + 1) * sizeof (char *));
result[n_args] = NULL;
for (i = 0; i < n_args; i++)
{
SCM car = SCM_CAR (args);
if (!SCM_STRINGP (car))
{
free (result);
scm_wrong_type_arg ("allocate_string_pointers", SCM_ARGn, car);
}
result[i] = SCM_STRING_CHARS (SCM_CAR (args));
args = SCM_CDR (args);
}
*num_args_return = n_args;
return result;
}
SCM_DEFINE (scm_dynamic_args_call, "dynamic-args-call", 3, 0, 0,
(SCM func, SCM dobj, SCM args),
"Call the C function indicated by @var{func} and @var{dobj},\n"
@ -397,9 +372,12 @@ SCM_DEFINE (scm_dynamic_args_call, "dynamic-args-call", 3, 0, 0,
fptr = (int (*) (int, char **)) SCM_NUM2ULONG (1, func);
SCM_DEFER_INTS;
argv = scm_make_argv_from_stringlist (args, &argc, FUNC_NAME, SCM_ARG3);
argv = allocate_string_pointers (args, &argc);
/* if the procedure mutates its arguments, the original strings will be
changed -- in Guile 1.6 and earlier, this wasn't the case since a
new copy of each string was allocated. */
result = (*fptr) (argc, argv);
scm_free_argv (argv);
free (argv);
SCM_ALLOW_INTS;
return SCM_MAKINUM (0L + result);