bool decode_primitive_type(const char *parameter, void **value, ffi_type **type)
{
const char *prefix;
prefix = NULL;
*value = NULL;
*type = NULL;
// If a colon exists, then everything before it is a type
if (strchr(parameter, ':')) {
// Extract the two components.
prefix = strndupa(parameter, strchr(parameter, ':') - parameter);
parameter = strchr(parameter, ':') + 1;
} else {
intmax_t n;
char *string;
// No type was specified, so there are only two possibilities,
// If this is a legal number, then it's an int. Otherwise, this is a
// string.
if (check_parse_long(parameter, &n)) {
*type = &ffi_type_sint;
*value = malloc(ffi_type_sint.size);
memcpy(*value, &n, ffi_type_sint.size);
return true;
}
// This must be a string.
*type = &ffi_type_pointer;
*value = malloc(ffi_type_pointer.size);
string = strdup(parameter);
memcpy(*value, &string, ffi_type_pointer.size);
return true;
}
if (decode_type_prefix(prefix, parameter, type, value, NULL) != true) {
builtin_warning("parameter decoding failed");
return false;
}
return true;
}
// Usage:
//
// dlcall $RTLD_DEFAULT "printf" "hello %s %u %c" $USER 123 int:10
//
static int call_foreign_function(WORD_LIST *list)
{
unsigned nargs;
int opt;
ffi_cif cif;
ffi_type **argtypes;
ffi_type *rettype;
void **values;
void *handle;
void *func;
char *prefix;
char *format;
char *resultname;
nargs = 0;
argtypes = NULL;
values = NULL;
format = NULL;
prefix = NULL;
rettype = &ffi_type_void;
resultname = "DLRETVAL";
reset_internal_getopt();
// $ dlcall [-a abi] [-r type] [-n name]
while ((opt = internal_getopt(list, "a:r:n:")) != -1) {
switch (opt) {
case 'a':
builtin_warning("FIXME: only abi %u is currently supported", FFI_DEFAULT_ABI);
return 1;
break;
case 'r':
if (decode_type_prefix(prefix = list_optarg, NULL, &rettype, NULL, &format) != true) {
builtin_warning("failed to parse return type");
return 1;
}
break;
case 'n':
resultname = list_optarg;
break;
default:
builtin_usage();
return 1;
}
}
// Skip past any options.
if ((list = loptend) == NULL || list->next == NULL) {
builtin_usage();
return 1;
}
if (check_parse_ulong(list->word->word, (void *) &handle) == 0) {
builtin_warning("handle %s %p is not well-formed", list->word->word, handle);
return 1;
}
if (!(func = dlsym(handle, list->next->word->word))) {
builtin_warning("failed to resolve symbol %s, %s", list->next->word->word, dlerror());
return 1;
}
// Skip to optional parameters
list = list->next->next;
while (list) {
argtypes = realloc(argtypes, (nargs + 1) * sizeof(ffi_type *));
values = realloc(values, (nargs + 1) * sizeof(void *));
if (decode_primitive_type(list->word->word, &values[nargs], &argtypes[nargs]) != true) {
builtin_error("failed to decode type from parameter %s", list->word->word);
goto error;
}
nargs++;
list = list->next;
}
if (ffi_prep_cif(&cif, FFI_DEFAULT_ABI, nargs, rettype, argtypes) == FFI_OK) {
char *retval;
void *rc = alloca(rettype->size);
// Do the call.
ffi_call(&cif, func, rc, values);
// Print the result.
if (format) {
switch (rettype->size) {
case 1: asprintf(&retval, format, *(uint8_t *) rc); break;
case 2: asprintf(&retval, format, *(uint16_t *) rc); break;
case 4: asprintf(&retval, format, *(uint32_t *) rc, *(float *) rc); break;
case 8: asprintf(&retval, format, *(uint64_t *) rc, *(double *) rc); break;
case 16: asprintf(&retval, format, *(long double *) rc); break;
default:
builtin_error("cannot handle size %lu", rettype->size);
abort();
}
fprintf(stderr, "%s\n", retval);
bind_variable(resultname, retval, 0);
free(retval);
}
}
for (unsigned i = 0; i < nargs; i++)
free(values[i]);
free(values);
free(argtypes);
return 0;
error:
for (unsigned i = 0; i < nargs; i++)
free(values[i]);
free(values);
free(argtypes);
return 1;
}
// Usage:
//
// dlsym $RTLD_DEFAULT "errno"
//
static int get_symbol_address(WORD_LIST *list)
{
int opt;
void *handle;
void *symbol;
char *resultname;
char *format;
char *retval;
ffi_type *rettype;
handle = RTLD_DEFAULT;
resultname = "DLRETVAL";
rettype = NULL;
reset_internal_getopt();
// $ dlsym [-n name] [-h handle] symbol
while ((opt = internal_getopt(list, "d:h:n:")) != -1) {
switch (opt) {
case 'd':
if (decode_type_prefix(list_optarg, NULL, &rettype, NULL, &format) != true) {
builtin_warning("failed to parse dereference type");
return 1;
}
break;
case 'n':
resultname = list_optarg;
break;
case 'h':
if (check_parse_ulong(list_optarg, (void *) &handle) == 0) {
builtin_warning("handle %s %p is not well-formed", list_optarg, handle);
return EXECUTION_FAILURE;
}
break;
default:
builtin_usage();
return EX_USAGE;
}
}
// Skip past any options.
if ((list = loptend) == NULL) {
builtin_usage();
return EX_USAGE;
}
if (!(symbol = dlsym(handle, list->word->word))) {
builtin_warning("failed to resolve symbol %s, %s", list->word->word, dlerror());
return EXECUTION_FAILURE;
}
if (rettype == NULL) {
asprintf(&retval, "pointer:%p", symbol);
} else {
retval = encode_primitive_type(format, rettype, symbol);
}
if (interactive_shell) {
fprintf(stderr, "%s\n", retval);
}
bind_variable(resultname, retval, 0);
free(retval);
return EXECUTION_SUCCESS;
}
// Usage:
//
// dlcall "printf" "hello %s %u %c" $USER 123 int:10
//
static int call_foreign_function(WORD_LIST *list)
{
unsigned nargs;
unsigned i;
int opt;
ffi_cif cif;
ffi_type **argtypes;
ffi_type *rettype;
void **values;
void *handle;
void *func;
char *prefix;
char *format;
char *resultname;
nargs = 0;
argtypes = NULL;
values = NULL;
format = NULL;
prefix = NULL;
rettype = &ffi_type_void;
resultname = "DLRETVAL";
handle = RTLD_DEFAULT;
reset_internal_getopt();
// $ dlcall [-a abi] [-r type] [-n name] [-h handle] symbol args...
while ((opt = internal_getopt(list, "h:a:r:n:")) != -1) {
switch (opt) {
case 'a':
builtin_warning("FIXME: only abi %u is currently supported", FFI_DEFAULT_ABI);
return 1;
break;
case 'r':
if (decode_type_prefix(prefix = list_optarg, NULL, &rettype, NULL, &format) != true) {
builtin_warning("failed to parse return type");
return 1;
}
break;
case 'n':
resultname = list_optarg;
break;
case 'h':
if (check_parse_ulong(list_optarg, (void *) &handle) == 0) {
builtin_warning("handle %s %p is not well-formed", list_optarg, handle);
return EXECUTION_FAILURE;
}
break;
default:
builtin_usage();
return EX_USAGE;
}
}
// Skip past any options.
if ((list = loptend) == NULL) {
builtin_usage();
return EX_USAGE;
}
if (!(func = dlsym(handle, list->word->word))) {
builtin_warning("failed to resolve symbol %s, %s", list->word->word, dlerror());
return 1;
}
// Skip to optional parameters
list = list->next;
while (list) {
argtypes = realloc(argtypes, (nargs + 1) * sizeof(ffi_type *));
values = realloc(values, (nargs + 1) * sizeof(void *));
if (decode_primitive_type(list->word->word, &values[nargs], &argtypes[nargs]) != true) {
builtin_error("failed to decode type from parameter %s", list->word->word);
goto error;
}
nargs++;
list = list->next;
}
if (ffi_prep_cif(&cif, FFI_DEFAULT_ABI, nargs, rettype, argtypes) == FFI_OK) {
char *retval;
void *rc = alloca(rettype->size);
// Do the call.
ffi_call(&cif, func, rc, values);
// Decode the result.
if (format) {
retval = encode_primitive_type(format, rettype, rc);
// If this is an interactive shell, print the output.
if (interactive_shell) {
fprintf(stderr, "%s\n", retval);
}
// Save the result to the requested location.
bind_variable(resultname, retval, 0);
// Bash maintains it's own copy of this string, so we can throw it away.
free(retval);
}
}
for (i = 0; i < nargs; i++)
free(values[i]);
free(values);
free(argtypes);
return 0;
error:
for (i = 0; i < nargs; i++)
free(values[i]);
free(values);
free(argtypes);
return 1;
}
static int generate_native_callback(WORD_LIST *list)
{
int nargs;
void *callback;
ffi_cif *cif;
ffi_closure *closure;
ffi_type **argtypes;
ffi_type *rettype;
char **proto;
char *resultname = "DLRETVAL";
char opt;
reset_internal_getopt();
// $ dlcall [-a abi] [-r type] [-n name]
while ((opt = internal_getopt(list, "a:r:n:")) != -1) {
switch (opt) {
case 'n':
resultname = list_optarg;
break;
default:
builtin_usage();
return EX_USAGE;
}
}
// Skip past any options.
if ((list = loptend) == NULL || !list->next) {
builtin_usage();
return EX_USAGE;
}
closure = ffi_closure_alloc(sizeof(ffi_closure), &callback);
cif = malloc(sizeof(ffi_cif));
argtypes = NULL;
proto = malloc(sizeof(char *));
proto[0] = strdup(list->word->word);
nargs = 0;
list = list->next;
// Second parameter must be the return type
if (decode_type_prefix(list->word->word,
NULL,
&rettype,
NULL,
NULL) != true) {
builtin_warning("couldnt parse the return type %s", list->word->word);
return EXECUTION_FAILURE;
}
// Skip past return type
list = list->next;
while (list) {
argtypes = realloc(argtypes, (nargs + 1) * sizeof(ffi_type *));
proto = realloc(proto, (nargs + 1 + 1) * sizeof(char *));
if (decode_type_prefix(list->word->word, NULL, &argtypes[nargs], NULL, &proto[nargs+1]) != true) {
builtin_error("failed to decode type from parameter %s", list->word->word);
goto error;
}
list = list->next;
nargs++;
}
if (ffi_prep_cif(cif, FFI_DEFAULT_ABI, nargs, rettype, argtypes) == FFI_OK) {
// Initialize the closure.
if (ffi_prep_closure_loc(closure, cif, execute_bash_trampoline, proto, callback) == FFI_OK) {
char retval[1024];
snprintf(retval, sizeof retval, "pointer:%p", callback);
fprintf(stderr, "%s\n", retval);
bind_variable(resultname, retval, 0);
}
}
//free(argtypes);
return 0;
error:
//free(argtypes);
return 1;
}
