Hi Irrwahn,
On 01/06/2016 11:24 PM, [email protected] wrote:
Note: I didn't try to undertand what the code is intended
to do, just commenting on some obvious flaws.
>void scan_buffer (char **ptr, char *command, char *name, char *str1, char
*str2)
>{
> FILE *fp;
> char *cad1, *cad2, *res;
>
> cad1=(char*)malloc(1024*sizeof(char));
Better C style would've been:
cad1=malloc(1024);
Casting malloc()'s return value is nonsense and potentially dangerous,
sizeof(char) is always guaranteed to equal 1.
[...]
> cad2 = strstr((char *) cad1, name);
> res = strstr((char *) cad2, str1);
Now you assigned to cad2 and res and lost your only reference
to your meticulously allocated buffers! (More bogus casts, BTW.)
[...]
And then you tried to free something that was not a pointer value
returned by any of the *alloc() functions:
> // free(cad2);
> // free(res);
[...]
As I said, I didn't try to guess the intention - if you want to
work in-place an the string or if you're actually looking for strcpy().
HTH, regards
Irrwahn
And thanks for your replay :)
I think that the origin of the issue is in the 'strstr' function. Have a
look at the 'scan_dim' method. This method runs 'backend 8' and edits
the textual output in a file named 'output'. It also returns an integer
'cont' (the number of available active wifis).
At the end of this method I can free *cad1; I also can free *cad2...;
*But i can't free both pointers*. Maybe the have common memory
addresses? I think so.
Here is the new code:
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
int N;
int scan_dim();
void scan_buffer (char **ptr, char *command, char *name, char *str1,
char *str2);
int main(int argc, char **argv)
{
int i;
char **_essid, **_address, **_quality;
N=scan_dim();
_essid = (char**)malloc(N*sizeof(char*));
if(!_essid) {printf("Fallo de asignación de memoria\n"); exit(-1);}
_address = (char**)malloc(N*sizeof(char*));
if(!_address) {printf("Fallo de asignación de memoria\n"); exit(-1);}
_quality = (char**)malloc(N*sizeof(char*));
if(!_quality) {printf("Fallo de asignación de memoria\n"); exit(-1);}
scan_buffer (_essid, "/usr/lib/netman/bin/backend 8", "ESSID:",
"\"", "\n");
scan_buffer (_quality, "/usr/lib/netman/bin/backend 8", "Quality=",
"=" , "Signal level");
scan_buffer (_address, "/usr/lib/netman/bin/backend 8", "Address:", "
" , "\n");
for(i=0; i<N; i++)
{
printf("%s\n", _essid[i]);
free(_essid[i]);
}
for(i=0; i<N; i++)
{
printf("%s\n", _address[i]);
free(_address[i]);
}
for(i=0; i<N; i++)
{
printf("%s\n", _quality[i]);
free(_quality[i]);
}
char **num, **denom;
num = (char**)malloc(N*sizeof(char*));
if(!num) {printf("Fallo de asignación de memoria\n"); exit(-1);}
for(i=0; i<N; i++)
{
num[i] = (char*)malloc(3*sizeof(char));
if(!num[i]) {printf("Fallo de asignación de memoria\n");
exit(-1);
}
}
denom = (char**)malloc(N*sizeof(char*));
if(!denom) {printf("Fallo de asignación de memoria\n"); exit(-1);}
for(i=0; i<N; i++)
{
denom[i] = (char*)malloc(3*sizeof(char));
if(!denom[i]) {printf("Fallo de asignación de memoria\n");
exit(-1);
}
}
free(_essid);
free(_address);
free(_quality);
system("rm -f output");
return 0;
}
void scan_buffer (char **ptr, char *command, char *name, char *str1,
char *str2)
{
FILE *fp;
char *cad1, *cad2, *res;
cad1=malloc(1024);
if(!cad1) {printf("Fallo de asignación de memoria\n"); exit(-1);}
cad2=malloc(1024);
if(!cad2) {printf("Fallo de asignación de memoria\n"); exit(-1);}
res=malloc(1024);
if(!res) {printf("Fallo de asignación de memoria\n"); exit(-1);}
fp = fopen("output", "r");
if(!fp) exit(-1);
int cont=0;
while (fgets(cad1, 1024, fp))
{
if(strstr((char *) cad1, name))
{
cad2 = strstr((char *) cad1, name);
res = strstr((char *) cad2, str1);
if(name!="Address:")
{
int bool=0;
int i=0;
int n,m;
while ((bool!=1) && (res[i]!='\0'))
{
if(str2[0]==res[i])
{
m=i; n=0;
while ((bool!=1) && (str1[n]==res[m]))
{
n++; m++;
if (n == strlen(res)) bool=1;
}
}
i++;
}
for (i=(m-n); res[i]!='\0';i++) res[i]='\0';
}
else res[strlen(res)]='\0';
int j=1;
while(res[strlen(res)-j]==' ' || res[strlen(res)-j]=='\"' ||
res[strlen(res)-j]=='\n') {res[strlen(res)-j]='\0'; j++;}
j=0;
while(j<strlen(res)) {res[j]=res[j+1]; j++;}
res[j]='\0';
ptr[cont] = (char*)malloc(strlen(res)*sizeof(char));
if(!ptr[cont]) {printf("Fallo de asignación de memoria\n");
exit(-1);}
strcpy(ptr[cont], res);
ptr[cont][strlen(res)]='\0';
cont++;
}
}
free(cad1);
// free(cad2);
// free(res);
fclose(fp);
return;
}
int scan_dim ()
{
FILE *fp, *fp1;
char *cad1, *cad2;
cad1=malloc(1024);
if(!cad1) {printf("Fallo de asignación de memoria\n"); exit(-1);}
cad2=malloc(1024);
if(!cad2) {printf("Fallo de asignación de memoria\n"); exit(-1);}
fp = popen("/usr/lib/netman/bin/backend 8", "r");
if(!fp) exit(-1);
fp1 = fopen("output", "w");
if(!fp1) exit(-1);
int cont=0;
while (fgets(cad1, 1024, fp))
{
if(strstr((char *) cad1, "Address:"))
{
cad2 = strstr((char *) cad1, "Address:");
fprintf(fp1, "%s", cad2);
cont++;
}
else if(strstr((char *) cad1, " "))
{
cad2 = strstr((char *) cad1, " ");
fprintf(fp1, "%s", cad2);
}
}
// free(cad1);
free(cad2);
pclose(fp);
fclose(fp1);
return cont;
}
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