Comment vérifier l'allocation dynamique

Question

Comment puis-je vérifier si j'utilise correctement l'allocation dynamique dans mon code C. C'est une affectation pour uni. Quand je mets mon code dans le système de correction automatique de mon professeur, j'obtiens une erreur pour l'allocation dynamique. Mon code:

#include <stdio.h> 
#include <string.h> 
#include <unistd.h> 
#include <stdlib.h> 
#include <sys/wait.h> 
#include <stdarg.h> 
#include <sys/types.h> 
#include <unistd.h> 
#include <ctype.h> 
int main() 
{ 

    for(;;) 
    { 
     char *cmd,*splitcmd; 
//*pr0,*pr1,*pr2 ; 
    size_t bufsize = 1024; 
     char pr1[bufsize]; 
     char pr2[bufsize]; 
     char pr0[bufsize]; 
     //char pr3[40]; 
     int i,j,nargc=0,characters; 
     char **cmdArray; 
     //size_t bufsize = 1024; 
     // size_t bufsizecmd =1024; 
     pid_t pid,wpid; 
     int status = 0; 
     char pr='$'; 
     char exit1[10]="exit"; 
     char *path; 
     path = getenv("PATH"); 

     putchar(pr); 


     cmd = malloc(bufsize * sizeof*cmd); 
     characters = getline(&cmd,&bufsize,stdin); 
//printf("cmd===> %s characters===> %d \n",cmd,characters); 
     if(cmd[characters-1]=='\n') 
     { 
      cmd[characters-1]='\0'; 
      characters--; 
     } 
//printf("cmd===> %s characters===> %d \n",cmd,characters); 


     cmdArray = malloc(bufsize*sizeof*cmdArray); 
     for (i = 0; i < bufsize; i++) 
     { 
      cmdArray[i]=malloc(bufsize*sizeof*cmdArray); 
     } 

     splitcmd=strtok(cmd," "); 
     // printf(" cmd==== %s\n",cmd); 
     while((splitcmd)) 
     { 
      strcpy(cmdArray[nargc],splitcmd); 
      if(cmdArray[nargc][(strlen(cmdArray[nargc]))-1]==' ') 
       cmdArray[nargc][(strlen(cmdArray[nargc]))-1]='\0'; 
//printf(" nargc====%d cmdArray===[%s] \n",nargc,cmdArray[nargc]); 
      nargc++; 
      splitcmd = strtok(NULL," "); 
     } 


//printf(" pr0 %s \n",pr0); 
//printf(" pr1 %s \n",pr1); 
//printf(" pr2 %s \n",pr2); 

     strcpy(pr0,cmdArray[0]); 
     if (strcmp(pr0, exit1) == 0) 
     { 
      //printf("---------->Eksodos apo to programma<---------- \n"); 
     free(cmd); 
      return (0); 
      exit(0); 

      //return (0); 
     } 
     else 
     { 


      if ((pid=fork()) == 0) 
      { 
       if(nargc ==1) 
       { 
        strcpy(pr0,cmdArray[0]); 
        char *argv[] = {path,NULL}; 

        execvp(pr0,argv); 

        for (i = 0; i < bufsize; i++) 
        { 
         free(cmdArray[i]); 
        } 
        free(cmdArray); 
      free(cmd); 
        exit(0); 
       } 
       else if(nargc==2) 
       { 
        strcpy(pr0,cmdArray[0]); 
        strcpy(pr1,cmdArray[1]); 
        char *argv[] = {pr0,pr1,NULL}; 

        execvp(pr0,argv); 
        exit(0); 

        for (i = 0; i < bufsize; i++) 
        { 
         free(cmdArray[i]); 
        } 
        free(cmdArray); 
      free(cmd); 
        exit(0); 
       } 
       else 
       { 

        strcpy(pr0,cmdArray[0]); 
        strcpy(pr1,cmdArray[1]); 
        strcpy(pr2,cmdArray[2]); 

        //printf("cmdddddddd****====%s \n",*cmdArray); 
        char *argv[] = {pr0,pr1,pr2,NULL}; 

        execvp(argv[0],argv); 

        for (i = 0; i < bufsize; i++) 
        { 
         free(cmdArray[i]); 
        } 
        free(cmdArray); 
      free(cmd); 
        exit(0); 
       } 
      } 

      wait(&status); 

     } 

    } 
} 

Answer 1

Il n'y a pas libre() correspondant pour cmd = (char *)malloc(bufsize * sizeof(char));.

En outre, ce bloc de code:

strcpy(pr0,cmdArray[0]); 
if (strcmp(pr0, exit1) == 0) 
{ 
    //printf("---------->Eksodos apo to programma<---------- \n"); 
free(cmd); 
    return (0); 
    exit(0); 
    //return (0); 
} 

aura besoin de cette

for (i = 0; i < bufsize; i++) 
{ 
    free(cmdArray[i]); 
} 
free(cmdArray); 

avant la

free(cmd); 

---

Dans ce bloc de code, il y a deux exit() appels:

else if(nargc==2) 
{ 
    strcpy(pr0,cmdArray[0]); 
    strcpy(pr1,cmdArray[1]); 
    char *argv[] = {pr0,pr1,NULL}; 

    execvp(pr0,argv); 
    exit(0); 

    for (i = 0; i < bufsize; i++) 
    { 
     free(cmdArray[i]); 
    } 
    free(cmdArray); 
free(cmd); 
    exit(0); 
} 

L'un immédiatement après l'execvp(pr0,argv); empêche l'un des appels free() d'être exécutés. Il doit être retiré.