[Linux-programlama] Re: gcc altında strcmp - gets gibi string fonksiyonlarının kullanımı.

---------

[Linux-programlama] Re: gcc altında strcmp - gets gibi string fonksiyonlarının kullanımı.

From: YILDIRIM <linux_at_isadamlari.org>
Date: Thu, 10 Jan 2008 01:21:14 +0200
Message-ID: <478556EA.6060500@isadamlari.org>
Ustun ERGENOGLU wrote:
              while(comand[i]!=32){
                cmd[i]=comand[i];
                i++;
              }

programınız yukarıda yazdığım kısımda segmentation fault veriyor.
yukarıdaki döngüde string'in uzunluğunu kontrol etmediğiniz için,
stringde de boşluk karakteri olmadığı için döngü stringin dışına
çıkıyor, sonrasında da segmentation fault. gdb kullanırsanız bu gibi
hataların nasıl oluştuğunu görebilirsiniz. m. ali vardar'ın
www.linuxprogramlama.com/documents/gdb.pdf adresinde güzel bir türkçe
gdb kılavuzu var.

üstün

09.01.2008 tarihinde YILDIRIM <linux@isadamlari.org> yazmış:
  
 Ustun ERGENOGLU wrote:
 nasıl kullandığınızı belirtirseniz, yardımcı olacak birileri çıkabilir.

üstün

09.01.2008 tarihinde YILDIRIM <linux@isadamlari.org> yazmış:


 Linux altında gcc kullanarak derleme yaptığımda string.h kütüphanesinde
bulunan gets(), strcmp() gibi string fonksiyonlarından kaynaklanan
"segmentation fault" hataları alıyorum. Bu problemi çözmenin bir yolu
var mıdır?
Şimdiden yardımcı olan arkadaşlara teşekkür ederim.

Mehmet Salih YILDIRIM
_______________________________________________
Linux-programlama mailing list
Linux-programlama@liste.linux.org.tr
http://liste.linux.org.tr/mailman/listinfo/linux-programlama


 _______________________________________________
Linux-programlama mailing list
Linux-programlama@liste.linux.org.tr
http://liste.linux.org.tr/mailman/listinfo/linux-programlama


 Aşağıda bi programın şablonu olarak hazırladığım kodlar bulunmakta.
Arkadaşım windows altında bir derleyiciyle (dev c) derlediğinde sorunsuz
çalışıyor. Fakat Linux altında gcc ile derlediğimde derleme başarılı oluyor
fakat "help" komutu gibi komutları verdiğimde "segmentation fault" verip
programı sonlandırıyor. Sorunun string.h kütüphanesindeki fonksiyonlardan
kaynaklandığını düşünüyorum. İlgilenen herkese teşekkür ederim.

 Mehmet Salih YILDIRIM


 <code>

              // prevent program crash when using commands with no
parameters or with not expected value of parameters //
              // for whoami and logout it is not necacery to define them as
a "program" //



                        // ANA PROGRAM //

 #include <stdio.h>
 //#include <stdlib.h>
 #include <string.h>



 static char actvusr[20]="testuser";


 int main ()  {

     char pathp[20];
     char param2[20];
     char param1[20];
     char cmd[20];
     char comand[20];
     int i,j,k;

     printf("\n\n\n  Welcome FS-1a \n");
     printf("\n by A.Egitmen & M.S.Yildirim\n\n\n");
     printf("\n For instructions type 'help'\n\n\n");



     do {
         printf("/%s>",actvusr);
         gets(comand);
               i=0;
               j=0;
               k=0;
               while(comand[i]!=32){
                 cmd[i]=comand[i];
                 i++;
               }
               cmd[i]='\0';
               i++;


//______________________________________________________________________________________________________________


   /*help*/     if(!strcmp(cmd,"help")){

                             printf("\n Login Usage      : login
'username'\n ");
                             printf("\n Dir Usage        : dir
'pathname'\n");
                             printf("\n Copy Usage       : cp
'source''FILENAME' 'destination''FILENAME'\n");

                             printf("\n Delete Usage     : del
'source2''FILENAME'\n");
                             printf("\n ReaderList Usage : rl\n" );
                             printf("\n Receive Usage    : receive
'FILENAME'\n");
                             printf("\n Send Usage       : send 'FILENAME'
'USERNAME'\n");
                             printf("\n Whoami Usage     : whoami\n");
                             printf("\n Setpass Usage    : setp\n");
                             printf("\n Logout Usage     : logout\n");
                             printf("\n Exit Usage       : exit\n");


                      }

//_____________________________________________________________________________________________________________


   /*login*/   else      if(!strcmp(cmd,"login")){
                      if(strcmp(actvusr,"\0")){
                        printf("\n You Have Already Logged \n");
                        }
                      else{

                         while(comand[i]!=32){
                            param1[j]=comand[i];
                            i++;
                            j++;
                         }
                         param1[j]='\0';

                     printf("\n command  : %s\n",cmd );
                     printf("\n param1   : %s\n",param1);
                   // - login call -  if pass match return =>
actvuser=username
                   // write system date to lastlogin.txt
                   // find username from actvuser.dat and write 1 to there
                   // you will rechange it to 0 when logout
                      }
                   }

//___________________________________________________________________________________________________________

   /*dir*/    else      if(!strcmp(cmd,"dir")){
                       if(!strcmp(actvusr,"\0")){
                         printf("\n Please Login Before Using Commands\n");
                         }
                         else{
                           while(comand[i]!=32){
                            param1[j]=comand[i];
                            i++;
                            j++;
                           }
                         param1[j]='\0';
                         printf("\n command  : %s\n",cmd );
                         printf("\n param1   : %s\n",param1);

                         // call dir ,  print files while in dir; return
void
                         }

                     }

//_____________________________________________________________________________________________________________


 /*COPY*/     else      if(!strcmp(cmd,"cp")){
                         if(!strcmp(actvusr,"\0")){
                            printf("\n Please Login Before Using
Commands\n");
                         }
                         else{

                           while(comand[i]!=32){
                            param1[j]=comand[i];
                            i++;
                            j++;
                           }
                         param1[j]='\0';

                         i++;
                          while(comand[i]!=32){
                            param2[k]=comand[i];
                            i++;
                            k++;
                          }
                         param2[k]='\0';
                         printf("\n command  : %s\n",cmd );
                         printf("\n param1   : %s\n",param1);
                         printf("\n param2   : %s\n",param2);
                         i=0;
                          while(param1[i]!=47){
                            pathp[i]=param1[i];
                            i++;
                          }
                          pathp[i]='\0';

                         printf("\n path : %s\n",pathp);

                     //get user id from uid ; with uid get supervisor
information from users.dat
                     //if ok then call cp
                     //if not get read permision for pathp from permis.txt
                     //if ok call cp ;
                     //if not cancel it
                     //--call cp-- return nothing//

                      }
                   }

//_____________________________________________________________________________________________________________


   /*DELETE*/  else   if(!strcmp(cmd,"del")){
                         if(!strcmp(actvusr,"\0")){
                            printf("\n Please Login Before Using
Commands\n");
                         }
                         else{
                            while(comand[i]!=32){
                            param1[j]=comand[i];
                            i++;
                            j++;
                           }
                         param1[j]='\0';
                         printf("\n command  : %s\n",cmd );
                         printf("\n param1   : %s\n",param1);
                          while(param1[i]!=47){
                            pathp[i]=param1[i];
                            i++;
                          }
                          pathp[i]='\0';

                         printf("\n path : %s\n",pathp);
                     //get user id from uid ; with uid get supervisor
information from users.dat
                     //if ok then call del
                     //if not get read permision for pathp from permis.txt
                     //if ok call del ;
                     //if not cancel it
                     //--call del-- return nothing//

                       }
                   }

//_____________________________________________________________________________________________________________


   /*ReaderList*/ else  if(!strcmp(cmd,"rl")){
                       if(!strcmp(actvusr,"\0")) {
                          printf("\n Please Login Before Using Commands\n");
                       }
                       else{

                       //call rl ; in rl open spool/username/files.txt
                       //read it line by line write it and return void

                       }
                   }

//_______________________________________________________________________________________________________________

 /*Whoami*/  else  if(!strcmp(cmd,"whoami")){
                   if(!strcmp(actvusr,"\0")){
                   printf("\nUnidentified Person\n");
                   }
                   else{
                        printf("\n %s \n",actvusr);
                   }
              }

//_______________________________________________________________________________________________________________

 /*Logout*/  else  if(!strcmp(cmd,"logout")){
                         if(!strcmp(actvusr,"\0")){
                            printf("\n You Are Not Seems to be Logged\n");
                         }
                         else{
                         printf("\n Thank You For Using FS-1a Please Contact
alper_egitmen@hotmail.com For Bugs \n" );
                         actvusr[0]='\0';

                         }

              }

//________________________________________________________________________________________________________________


  /*SEND*/  else   if(!strcmp(cmd,"send")){
                       if(!strcmp(actvusr,"\0")) {
                          printf("\n Please Login Before Using Commands\n");
                       }
                       else{
                           while(comand[i]!=32){
                            param1[j]=comand[i];
                            i++;
                            j++;
                           }
                         param1[j]='\0';

                         i++;
                          while(comand[i]!=32){
                            param2[k]=comand[i];
                            i++;
                            k++;
                          }
                         param2[k]='\0';
                         printf("\n command  : %s\n",cmd );
                         printf("\n param1   : %s\n",param1);
                         printf("\n param2   : %s\n",param2);

                       }


                 // call send without any permission check

           }



//_________________________________________________________________________________________________________________



 /*Receive*/  else  if(!strcmp(cmd,"receive")) {
                       if(!strcmp(actvusr,"\0")) {
                          printf("\n Please Login Before Using Commands\n");
                       }
                       else{
                           while(comand[i]!=32){
                            param1[j]=comand[i];
                            i++;
                            j++;
                           }
                         param1[j]='\0';
                         strcpy(param2,actvusr);

                         printf("\n command  : %s\n",cmd );
                         printf("\n param1   : %s\n",param1);
                         printf("\n param2   : %s\n",param2);

                      //call receive without any permission chech


                       }

              }


//________________________________________________________________________________________________________________




 /* SETPASS*/ else if(!strcmp(cmd,"setp")){
                       if(!strcmp(actvusr,"\0")) {
                          printf("\n Please Login Before Using Commands\n");
                       }
                       else{

                        //get id from uid , using id get information
"setpass" from users.dat
                        //if ok ; than as for old pass
                        //if ok ask new pass
                        //change pass with using id from passwd.dat
                        }

              }

//_______________________________________________________________________________________________________________

                     // commands ends //

         else if(!strcmp(cmd,"\0"));

         else
              printf("\n\n Unknown Command\n\n");


     }







    while(strcmp(cmd,"exit"));




  return 0;

 }

 </code>

_______________________________________________
Linux-programlama mailing list
Linux-programlama@liste.linux.org.tr
http://liste.linux.org.tr/mailman/listinfo/linux-programlama


    
_______________________________________________
Linux-programlama mailing list
Linux-programlama@liste.linux.org.tr
http://liste.linux.org.tr/mailman/listinfo/linux-programlama

  
Teşekkür ederim. gdb yi incelemeye başlıyorum.
Tekrar kolay gelsin.

_______________________________________________
Linux-programlama mailing list
Linux-programlama_at_liste.linux.org.tr
http://liste.linux.org.tr/mailman/listinfo/linux-programlama
Received on Thu 10 Jan 2008 - 00:49:52 EET

---------

Bu arsiv hypermail 2.2.0 tarafindan uretilmistir.