Invalid write and signal 11 error valgrind - c

Question

I'm trying to implement a program that operates on a list of generic value nodes (pointers to void). The program works as follows: Read each line of an input file that translates each line, interprets and performs a function.
Performs functions such as addition, subtraction, normalization, distance, increment, decrement ... Running with the values ​​of the nodes that are almost floats vectors.
To compile use:
g+ +-g-Wall-Wextra-Werror-pedantic main.cpp-o metbasicos.cpp metintermedios.cpp metavanzados.cpp eda.exe and I have no problems.
By using Valgrind've managed to eliminate all potential memory leaks and errors but one that I like and I can not resist putting it.
(valgrind - tool = memcheck - leak-check = full - show-reachable = yes. / eda.exe)
that's the whole main.cpp
int main(){
Lista *L = create_list();
char *mystring = NULL;
char *str, *charv1, *charv2, *simbol;
char *vec = NULL;
int operation, Lsize, v1, v2, res; /
vector *auxv1 = NULL;
vector *auxv2 = NULL;
Nodo *ultimo = NULL;
str = charv1 = charv2 = simbol = NULL;
while (fgets (mystring ,100 , stdin) != NULL){ // line 21, where the errors happens
sscanf (mystring,"%s",str);
res = strlen (str); /
if(mystring[0] == 'p') operation = 1; // print
else if(mystring[0] == 'i') operation = 2; // increase
else if(mystring[0] == 'd') {
if(mystring[1] == 'i') operation = 4; // distance
else if(mystring[1] == 'e') operation = 5; // decrease
else operation = 10; // destroy
}
else if(mystring[0] == 'n') {
if (mystring[1] == 'e') operation = 13; //nearest
else{
if (res == 4) operation = 7; // norm
else operation = 6; // normalize
}
}
else if(mystring[0] == 'c'){
if (mystring[1] == 'r') operation = 11; // create
else operation = 12; // clone
}
else{
sscanf (mystring,"%s %s",str, simbol);
if (simbol[0] == '+') operation = 8; // +
else if(simbol[0] == '-') operation = 9; // -
else operation = 3; // dot
}
switch(operation)
{
case 1 : // print
sscanf (mystring,"%s %s",str, charv1);
v1 = strtol((charv1+1) , NULL , 10);
if (v1 > Lsize) printf ("ERROR");
else {
for (int i = v1; v1>Lsize-i; i++) next(L);
auxv1 = (vector*)(current(L))->valor;
print(auxv1);
L->actual = ultimo;
}
break;
case 2 : // increase
sscanf (mystring,"%s %s %s",str, charv1, charv2);
v1 = strtol((charv1+1) , NULL , 10);
v2 = strtol((charv2+1) , NULL , 10);
if (v1 > Lsize || v2 > Lsize) printf ("ERROR");
else {
for (int i = v1; v1>Lsize-i; i++) next(L);
auxv1 = (vector*)(current(L))->valor;
L->actual = ultimo;
for (int i = v2; v2>Lsize-i; i++) next(L);
auxv2 = (vector*)(current(L))->valor;
L->actual = ultimo;
incr(auxv1, auxv2);
for (int i = v1; v1>Lsize-i; i++) next(L);
L->actual->valor = (void*)auxv1;
ultimo = L->actual;
}
break;
case 3 : // dot
sscanf (mystring,"%s %s %s",charv1, str, charv2);
v1 = strtol((charv1+1) , NULL , 10);
v2 = strtol((charv2+1) , NULL , 10);
if (v1 > Lsize || v2 > Lsize) printf ("ERROR");
else {
for (int i = v1; v1>Lsize-i; i++) next(L);
auxv1 = (vector*)(current(L))->valor;
L->actual = ultimo;
for (int i = v2; v2>Lsize-i; i++) next(L);
auxv2 = (vector*)(current(L))->valor;
L->actual = ultimo;
printf("%f\n", dot(auxv1, auxv2));
}
break;
case 4 : // distance
sscanf (mystring,"%s %s %s", str, charv1, charv2);
v1 = strtol((charv1+1) , NULL , 10);
v2 = strtol((charv2+1) , NULL , 10);
if (v1 > Lsize || v2 > Lsize) printf ("ERROR");
else {
for (int i = v1; v1>Lsize-i; i++) next(L);
auxv1 = (vector*)(current(L))->valor;
L->actual = ultimo;
for (int i = v2; v2>Lsize-i; i++) next(L);
auxv2 = (vector*)(current(L))->valor;
L->actual = ultimo;
printf("%f\n", distance(auxv1, auxv2));
}
break;
case 5 : // decrease
sscanf (mystring,"%s %s %s",str, charv1, charv2);
v1 = strtol((charv1+1) , NULL , 10);
v2 = strtol((charv2+1) , NULL , 10);
if (v1 > Lsize || v2 > Lsize) printf ("ERROR");
else {
for (int i = v1; v1>Lsize-i; i++) next(L);
auxv1 = (vector*)(current(L))->valor;
L->actual = ultimo;
for (int i = v2; v2>Lsize-i; i++) next(L);
auxv2 = (vector*)(current(L))->valor;
L->actual = ultimo;
decr(auxv1, auxv2);
for (int i = v1; v1>Lsize-i; i++) next(L);
L->actual->valor = (void*)auxv1;
ultimo = L->actual;
}
break;
case 6 : // normalize
sscanf (mystring,"%s %s",str, charv1);
v1 = strtol((charv1+1) , NULL , 10);
if (v1 > Lsize) printf ("ERROR");
else {
for (int i = v1; v1>Lsize-i; i++) next(L);
auxv1 = (vector*)(current(L))->valor;
normalize(auxv1);
L->actual->valor = (void*)auxv1;
ultimo = L->actual;
}
break;
case 7 : // norm
sscanf (mystring,"%s %s",str, charv1);
v1 = strtol((charv1+1) , NULL , 10);
if (v1 > Lsize) printf ("ERROR");
else {
for (int i = v1; v1>Lsize-i; i++) next(L);
auxv1 = (vector*)(current(L))->valor;
printf("%.3f\n", norm(auxv1));
L->actual = ultimo;
}
break;
case 8 : // +
sscanf (mystring,"%s %s %s", charv1, str, charv2);
v1 = strtol((charv1+1) , NULL , 10);
v2 = strtol((charv2+1) , NULL , 10);
if (v1 > Lsize || v2 > Lsize) printf ("ERROR");
else {
for (int i = v1; v1>Lsize-i; i++) next(L);
auxv1 = (vector*)(current(L))->valor;
L->actual = ultimo;
for (int i = v2; v2>Lsize-i; i++) next(L);
auxv2 = (vector*)(current(L))->valor;
L->actual = ultimo;
insert(L,crear_nodo_floatvec(add(auxv1, auxv2)));
ultimo = L->actual;
print((vector*)(current(L))->valor);
Lsize++;
}
break;
case 9 : // -
sscanf (mystring,"%s %s %s", charv1, str, charv2);
v1 = strtol((charv1+1) , NULL , 10);
v2 = strtol((charv2+1) , NULL , 10);
if (v1 > Lsize || v2 > Lsize) printf ("ERROR");
else {
for (int i = v1; v1>Lsize-i; i++) next(L);
auxv1 = (vector*)(current(L))->valor;
L->actual = ultimo;
for (int i = v2; v2>Lsize-i; i++) next(L);
auxv2 = (vector*)(current(L))->valor;
L->actual = ultimo;
insert(L,crear_nodo_floatvec(sub(auxv1, auxv2)));
ultimo = L->actual;
print((vector*)(current(L))->valor);
Lsize++;
}
break;
case 10 : // destroy
sscanf (mystring, "%s %s", str, charv1);
v1 = strtol((charv1+1) , NULL , 10);
if (v1 > Lsize) printf ("ERROR");
else {
for (int i = v1; v1>Lsize-i; i++) next(L);
if (v1 == Lsize) {
ultimo = L->actual->siguiente; //si eliminamos el último, asignamos el último al anterior //ojo
remove(L);
Lsize--;
}
else {
remove(L);
Lsize--;
L->actual = ultimo; //ojo
}
}
break;
case 11 : // create
vec = (char *)malloc(sizeof(char)*93); //100 - tamaño de str
sscanf (mystring, "%s %s", str, vec);
printf("%s %s \n", str, vec);
insert(L, crear_nodo_floatvec(create_vector(NumsVector(vec,strlen(vec)), getfloat(vec)))); //Creamos un nodo cuyo valor sea un vector de floats y lo insertamos en la lista
ultimo = L->actual; //ojo
Lsize++;
break;
case 12 : // clone
sscanf (mystring, "%s %s", str, charv1);
v1 = strtol((charv1+1) , NULL , 10);
if (v1 > Lsize) printf ("ERROR");
else {
for (int i = v1; v1>Lsize-i; i++) next(L);
auxv1 = (vector*)(current(L))->valor;
insert(L,crear_nodo_floatvec(create_vector(auxv1->size, auxv1->data))); //Creamos una copia del nodo indicado y lo insertamos
ultimo = L->actual; //ojo
Lsize++;
}
break;
case 13 : // nearest := vector* nearest(Lista* l, vector* v); *
sscanf (mystring,"%s %s",str, charv1);
v1 = strtol((charv1+1) , NULL , 10);
if (v1 > Lsize) printf ("ERROR");
else {
for (int i = v1; v1>Lsize-i; i++) next(L);
auxv1 = (vector*)(current(L))->valor;
print(nearest(L,auxv1));
L->actual = ultimo;
}
break;
default :
printf("operation value is: %d\n", operation);
break;
operation = 0;
}
}
Here you have the file that contains the implementation of some basic functions and implementation of the node vector and list:
typedef struct {
float* data;
int size;
}vector;
struct Nodo{
void* valor;
struct Nodo* siguiente;
};
struct Lista{
Nodo* primero;
Nodo* actual;
};
vector *create_vector(int n, float* data){
vector *newvect = (vector*)malloc(sizeof(*newvect));
newvect->data = (float*)malloc(n*sizeof(float));
memcpy(newvect->data, data, sizeof(float) * n);
newvect->size = n;
return newvect;
destroy_vector(newvect);
}
void destroy_vector(vector* v){
free(v->data);
free(v);
}
void print(vector* v){
int size = v->size, i;
if (v == NULL) printf("ERROR");
else{
for (i = 0; i < size; ++i)
{
if(i == 0) printf("[%.1f,", v->data[i]);
else if(i == (size-1)) printf("%.1f]\n", v->data[i]);
else printf("%.1f,", v->data[i]);
}
}
Lista* create_list() //Creamos espacio en la lista
{
Lista *L = NULL;
return L;
}
void insert(Lista* l, Nodo* nodo){
Nodo *Naux = (Nodo*)malloc(sizeof(nodo));
Naux->valor = l->actual->valor;
Naux->siguiente = l->actual->siguiente;
l->actual = nodo;
nodo->siguiente = Naux;
free(Naux->siguiente);
free(Naux->valor);
free(Naux);
}
bool end(Lista* l){
return l->actual == NULL;
}
bool is_empty(Lista* l) {
return l->actual->valor == NULL;
}
void next(Lista* l){
if(end(l)) printf ("Error, final de lista");
else l->actual = l->actual->siguiente;
}
void remove(Lista* l){
if(not end(l)) {
Nodo *Naux = (Nodo*)malloc(sizeof(Nodo));
Naux = l->actual->siguiente;
l->actual->valor = Naux->valor;
l->actual->siguiente = Naux->siguiente;
free(Naux->siguiente);
free(Naux->valor);
free(Naux);
}
}
int size(Lista* l){
if(not is_empty(l)) return sizeof(l->actual->valor);
else return 0;
}
Nodo* current(Lista* l){
return l->actual;
}
Nodo* crear_nodo(){
Nodo *Naux = NULL;
return Naux;
}
Nodo* crear_nodo_floatvec(vector* valor) {
Nodo *Naux = crear_nodo();
Naux->valor = (vector*)malloc(sizeof(valor));
Naux->valor = (void*)valor;
return Naux;
}
int NumsVector(char *linea, int size){
int numsvector = 1;
int n;
for(n = 2; n<= size; n++){
if (linea[n] != '[' && linea[n] != ']'){
if(linea[n] == 44){
numsvector = numsvector + 1;
}
}
}
return numsvector;
}
float* getfloat(char *vec){
int size = strlen(vec);
vec[size] = '\0';
int n = NumsVector(vec,size), j = 0;
float *vf = (float*)malloc(n*sizeof(float));
vec[size-1]= ',';
char *p = vec + 1;
do {
sscanf(p, "%f,", &vf[j]);
while (*(p++) != ',') ;
}
while (++j < n);
return vf;
}
When I launch Valgrind, it shows me the next errors:
Memcheck, a memory error detector
==9392== Copyright (C) 2002-2011, and GNU GPL'd, by Julian Seward et al.
==9392== Using Valgrind-3.7.0 and LibVEX; rerun with -h for copyright info
==9392== Command: ./eda.exe
==9392==
==9392== Invalid write of size 1
==9392== at 0x519E244: _IO_getline_info (iogetline.c:84)
==9392== by 0x519D06A: fgets (iofgets.c:58)
==9392== by 0x401AA3: main (main.cpp:21)
==9392== Address 0x0 is not stack'd, malloc'd or (recently) free'd
==9392==
==9392==
==9392== Process terminating with default action of signal 11 (SIGSEGV)
==9392== Access not within mapped region at address 0x0
==9392== at 0x519E244: _IO_getline_info (iogetline.c:84)
==9392== by 0x519D06A: fgets (iofgets.c:58)
==9392== by 0x401AA3: main (**main.cpp:21**)
==9392== If you believe this happened as a result of a stack
==9392== overflow in your program's main thread (unlikely but
==9392== possible), you can try to increase the size of the
==9392== main thread stack using the --main-stacksize= flag.
==9392== The main thread stack size used in this run was 8388608.
==9392==
==9392== HEAP SUMMARY:
==9392== in use at exit: 0 bytes in 0 blocks
==9392== total heap usage: 0 allocs, 0 frees, 0 bytes allocated
==9392==
==9392== All heap blocks were freed -- no leaks are possible
==9392==
==9392== For counts of detected and suppressed errors, rerun with: -v
==9392== ERROR SUMMARY: 1 errors from 1 contexts (suppressed: 2 from 2)
When I try to execute the program it also shows me Segmentation fault, Core dumped
Is there anyone that can help me please?
the greatest part of the variables are written in spanish, I guess that's no a problem to understand de code.
Thank you

Answer 1

Look at theese two lines:
char *mystring = NULL;
and
while (fgets (mystring ,100 , stdin) != NULL){
You're dereferencing a NULLpointer.
You sure you don't want e.g.
char mystring[100];