Сегментация Fault fgets() двухпроходный ассемблер

Question

#include<string.h> 

typedef struct{ 
     char Mnemonic[7]; 
     int code; 
     } code; 

typedef struct{ 
     char label[10]; 
     unsigned int location; 
     } symbolTab; 

int opLook(char * mnemonic, code * optable) 
{ 
    int i = 0; 
    int value = 0; 
    for(i ; i<25 ; i++) 
    { 
     if(strcmp(mnemonic, optable[i].Mnemonic) == 0) 
     { 
      value = optable[i].code; 
      return value; 
     } 
    } 

    return value; 

} 


int opValid(char * mnemonic, code * optable) 
{ 
    int i = 0; 
    for(i ; i<25 ; i++) 
    { 
     if(strcmp(mnemonic, optable[i].Mnemonic) == 0) 
     { 
      return 1; 
     } 
    } 

    return 0; 

} 

int labelcheck(char * label, symbolTab * Table, int counter) 
{ 
    int i = 0; 
    int flag = 0; 

    if (counter == 0) 
    { 
     return flag; 
    } 
    else 
     { 
      for(i; i <counter; i ++) 
      { 
       if(strcmp(label, Table[i].label) == 0) 
       { 
        flag = 1; 
       } 

      } 

      return flag; 
     } 
} 




unsigned int labelVal(char * label, symbolTab * Table, int counter) 
{ 
    int i = 0; 

    for(i; i <counter; i ++) 
     { 
      if(strcmp(label, Table[i].label) == 0) 
       { 
        return Table[i].location; 
       } 
     } 


} 





void Assemble(char* filename) 
{ 
    unsigned int locctr = 0; /*location counter*/ 
    unsigned int prolen = 0; /*program length*/ 
    int mnemoVal; /*mnemonic Value in Int*/ 
    int labelctr = 0; 
    code Opta[25] = {{"ADD", 24},{"AND",88},{"COMP",40},{"DIV",36},{"J",60}, 
        {"JEQ",48},{"JGT",52},{"JLT",56},{"JSUB",72},{"LDA",00}, 
        {"LDCH",80},{"LDL", 8},{"LDX", 4},{"MUL",32},{"OR",68}, 
        {"RD",216},{"RSUB",76},{"STA",12},{"STCH",84},{"STL",20}, 
        {"STX",16},{"SUB",28},{"TD",224},{"TIX",44},{"WD",220}}; 
    symbolTab symTab[500];    
    char buffer[255]; 
    FILE * source; 
    FILE * interFile; 
    FILE * objF; 
    FILE * ListFile; 
    interFile = fopen("intermidiateFile.txt", "w+"); 
    ListFile = fopen("ListingFile.txt", "w+"); 
    objF = fopen("ObjectFile.txt", "w+"); 
    source = fopen("source.txt", "r"); 
    char * lab;  /*label*/ 
    char * mnemo; /*mnemonic*/ 
    char * operand; 
    char * address = "adress"; 
    unsigned int opeaddress; 



    fgets(buffer, 255, source); 

    if (buffer[0] != '.') 
    { 
     fprintf(interFile, "%s", buffer); 
    } 

    /*Getting first line and initialization of Location Counter*/ 

    if(buffer[0] == '.')    /* if the line is a comment continue with the next iteration of the loop*/ 
     { 
      locctr = 0; 
     } 
    else 
    { 
     if(buffer[0] == ' ' || buffer[0] == '\t') 
     { 
      mnemo = strtok(buffer, " \t"); 
      operand = strtok(NULL, " \t"); 
      if(strcmp(mnemo, "START") == 0) 
      { 
       locctr = strtol(operand, NULL, 16); 
      } 

      else 
      { 
        /*error*/ 
      } 

     } 

     else 
     { 
      lab =strtok(buffer, " \t"); 
      mnemo = strtok(NULL, " \t"); 
      operand = strtok(NULL, " \t"); 

      if(strcmp(mnemo, "START") == 0) 
      { 
       locctr = strtol(operand, NULL, 16); 
      } 

      else 
      { 
        /*error*/ 
      } 


     } 

    } 


/* End of the location counter initialization */ 


    /*start while loop*/ 

    while(!feof(source)) 
    { 
      memset(lab, '\0', strlen(lab)); 
      memset(mnemo, '\0', strlen(mnemo)); 
      memset(operand, '\0', strlen(operand)); 

      fgets(buffer, 255, source); 

      fprintf(interFile, "%s", buffer); 

      if(buffer[0] == '.')    /* if the line is a comment continue with the next iteration of the loop*/ 
      { 
       continue; 
      } 

      else   /* Else for... If it is not a comment, then check if it start with a character or a space*/ 
      { 

       if(buffer[0] == ' ' || buffer[0] == '\t') /* If it start with a space, then it is just a mnemonic or mnemonic & operand*/ 
       { 
        mnemo = strtok(buffer, " \t\n\r"); 
        if (strcmp(mnemo, "END") == 0) 
        { 
        break; 
        } 

        if(strcmp(mnemo, "RSUB") == 0) 
        { 
         mnemoVal = opLook(mnemo, Opta); 
         fprintf(interFile, "%x %02x\n", locctr, mnemoVal); 
        } 

        else 
        { 
         operand = strtok(NULL, " \t\r\n"); 
         mnemoVal = opLook(mnemo, Opta); 
         fprintf(interFile, "%x %02x %s\n", locctr, mnemoVal, operand); 
        } 

       } 

       else  

       { 

        lab = strtok(buffer, " \t\n\r"); /* it has a label, mnemonic and operand*/ 

        if(labelcheck(lab, symTab, labelctr) == 0) /* check if the label is already in the symTab, if not, add it, otherwise it is an error*/ 
        {     
         strcpy(symTab[labelctr].label, lab);  
         symTab[labelctr].location = locctr; 
         labelctr++; 
         mnemo = strtok(NULL, " \t\n\r"); 
         if (strcmp(mnemo, "END") == 0) 
         { 
          break; 
         } 
         operand = strtok(NULL, " \t\n\r"); 
         mnemoVal = opLook(mnemo, Opta); 
        } 


        else 
        { 
         mnemo = strtok(NULL, " \t\n\r"); 
         if (strcmp(mnemo, "END") == 0) 
         { 
          break; 
         } 
         operand = strtok(NULL, " \t\n\r"); 
         mnemoVal = opLook(mnemo, Opta); 

        } 

        fprintf(interFile, "%x %s %02x %s\n", locctr, lab, mnemoVal, operand); 


       } 



      } 


      if(strcmp(mnemo, "WORD") == 0) 
      { 
       locctr = locctr + 3; 
      } 


      else if(strcmp(mnemo, "BYTE") == 0) 
      { 
       unsigned int val; 
       if (operand[0] =='C') 
       { 
        val = strlen(operand) - 3; 
        locctr = locctr + val; 
       } 

       else 
       { 
        val = (strlen(operand) - 3)/2; 
        locctr = locctr + val; 
       } 
      } 

      else if(strcmp(mnemo, "RESB") == 0) 
      { 
       locctr = locctr + atoi(operand); 
      } 

      else if(strcmp(mnemo, "RESW") == 0) 
      { 
       locctr = locctr + (3*atoi(operand)); 
      } 


      else 
      { 
       locctr= locctr + 3; 
      } 



    } 


      /* End of While loop*/ 

     prolen = locctr - symTab[0].location; 

     fprintf(interFile, "\n%x", prolen); 




    fclose(source); 
    fclose(interFile); 



    interFile = fopen("intermidiateFile.txt", "r"); 

    /*Start the Listing File and Object File  ---------------------Pass 2----------- */ 

     fgets(buffer, 255, interFile); 


    if(buffer[0] == '.')    /* if the line is a comment continue with the next iteration of the loop*/ 
     { 
      locctr = 0; 

      /*Error missung Start or Misplaced*/ 
     } 
    else 
    { 
     if(buffer[0] == ' ' || buffer[0] == '\t') 
     { 
      mnemo = strtok(buffer, " \t"); 
      operand = strtok(NULL, " \t"); 
      if(strcmp(mnemo, "START") == 0) 
      { 
       locctr = strtol(operand, NULL, 16); 
       strcpy(address, operand); 

       fprintf(ListFile, "%X %s %s\n", locctr, mnemo, operand); 
      } 

      else 
      { 
        /*error*/ 
      } 

     } 

     else 
     { 
      lab =strtok(buffer, " \t"); 
      mnemo = strtok(NULL, " \t"); 
      operand = strtok(NULL, " \t"); 

      if(strcmp(mnemo, "START") == 0) 
      { 
       locctr = strtol(operand, NULL, 16); 
       fprintf(ListFile, "%x %s %s %s\n", locctr, lab, mnemo, operand); 

       fprintf(objF, "H%s__%06x%06x\n", lab, locctr, prolen); 

      } 

      else 
      { 
       /*error*/ 
      } 
     } 
    } 



    while(!feof(interFile)) 
    { 

     memset(lab, '\0', strlen(lab)); 
     memset(mnemo, '\0', strlen(mnemo)); 
     memset(operand, '\0', strlen(operand)); 
     memset(address, '\0', strlen(address)); 
     memset(buffer, '\0', strlen(buffer)); 

     fgets(buffer, 255, interFile); 

     if (buffer[0] == '\r') 
     { 
      continue; 
     } 



     if(buffer[0] == ' ' || buffer[0] == '\t') 
     { 
      mnemo = strtok(buffer, " \t\n\r"); 
      if (strcmp(mnemo, "END") == 0) 
      { 
       break; 
      } 

      if(strcmp(mnemo, "RSUB") == 0) 
      { 
       memset(buffer, '\0', strlen(buffer)); 
       fgets(address, 255, interFile); 

       mnemoVal = opLook(mnemo, Opta); 
       fprintf(ListFile, "%s %s %X0000", address, mnemo, mnemoVal); 
      } 
      else 
      { 
       operand = strtok(NULL, " \t\r\n"); 
       mnemoVal = opLook(mnemo, Opta); 
       memset(buffer, '\0', strlen(buffer)); 
       fgets(address, 255, interFile); 
       if (labelcheck(operand, symTab, labelctr) == 1) 
       { 
        opeaddress = labelVal(operand, symTab, labelctr); 
       } 

       else 
       { 
        opeaddress = 0; 
        /* error*/ 
       } 


       fprintf(ListFile, "%s %s %s %02X%04X", address, mnemo, operand, mnemoVal, opeaddress); 
      }   


     } 


     else if (buffer[0] == '.') 
     { 
      fprintf(ListFile, "%s\n", buffer); 
     } 


     else 
     { 
      lab = strtok(buffer, " \t\n\r"); 
      mnemo = strtok(NULL, " \t\n\r"); 
      operand = strtok(NULL, " \t\n\r"); 
      mnemoVal = opLook(mnemo, Opta); 
      memset(buffer, '\0', strlen(buffer)); 
      fgets(address, 255, interFile); 
      if (labelcheck(operand, symTab, labelctr) == 1) 
       { 
        opeaddress = labelVal(operand, symTab, labelctr); 
       } 

      else 
       { 
        opeaddress = 0; 
        /* error*/ 
       } 
      fprintf(ListFile, "%s %s %s %s %02X%04X", address, lab, mnemo, operand, mnemoVal, opeaddress); 


     } 

    } 






    fclose(interFile); 
    fclose(objF); 
    fclose(ListFile); 
} 

Ошибка возникает в последнем цикле while при выполнении fgets(); Я посмотрел, есть ли у меня какая-либо переменная или синтаксис, но все выглядит нормально. Это часть двухпроходной сборки. Ошибка изменяется между fgets в последнем цикле while. Сначала я подумал, что это функция MemSet, но ошибка все равно произошло, когда я отмечаю их как комментарии

Answer 1

Из

char * address = "adress";

address указывает на Read Only Memory

Попытка изменить string literals (в вашем случае "adress") вызывает undefined behavior.

Тогда в последнем цикле

• strcpy(address, operand);
• memset(address, '\0', strlen(address));
• fgets(address, 255, interFile);

неверны.

Вы можете изменить эту переменную в простой массив символов с достаточно места для ваших нужд, например:

char address[128];