TO MIMIC THE DELGROUP COMMAND IN LINUX

INSTRUCTIONS ARE IN README. PLEASE DO REFER.

README.txt

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+***********************************************************************************************************
+		C PROGRAM TO MIMIC DELGROUP COMMAND IN LINUX USING C PROGRAM 
+				INSTRUCTIONS
+************************************************************************************************************
+THIS PROGRAM DELETES A GROUP NAME FROM "group" and "gshadow" file.
+1)Primarily all files related to this program should be in the same folder(like .c,.h,makefiles etc).
+2)Whatever be the system,defining a path in terminal is necessary.Specify the path in terminal.
+3)To compile the makefile use "mingw32-make -f makefile.mak".
+4)After compilation,enter "a groupname",where groupname is the name to be deleted from those files.
+5)Also in the terminal only the other group names except deleted group will be displayed.

client.c

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+#include<stdio.h>
+#include<string.h>
+#include<stdlib.h>
+#include "server.h"
+int main(int argc,char *argv[])
+{
+    if(argc==2)
+        delgroupGname(argv[1]);
+    else
+        printf("Please Enter the correct input");
+    return 0;
+}

group.txt

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+daemon:x:1:
+bin:x:2:
+sys:x:3:
+adm:x:4:syslog,anandms
+tty:x:5:
+disk:x:6:
+lp:x:7:
+mail:x:8:
+news:x:9:
+uucp:x:10:
+man:x:12:
+proxy:x:13:
+kmem:x:15:
+dialout:x:20:
+fax:x:21:
+voice:x:22:
+cdrom:x:24:anandms
+floppy:x:25:
+tape:x:26:
+sudo:x:27:anandms
+audio:x:29:pulse
+dip:x:30:anandms
+www-data:x:33:
+backup:x:34:
+operator:x:37:
+list:x:38:
+irc:x:39:
+src:x:40:
+gnats:x:41:
+shadow:x:42:
+utmp:x:43:
+video:x:44:
+sasl:x:45:
+plugdev:x:46:anandms
+staff:x:50:
+games:x:60:
+users:x:100:
+nogroup:x:65534:
+systemd-journal:x:101:
+systemd-timesync:x:102:
+systemd-network:x:103:
+systemd-resolve:x:104:
+systemd-bus-proxy:x:105:
+input:x:106:
+crontab:x:107:
+syslog:x:108:
+netdev:x:109:
+messagebus:x:110:
+uuidd:x:111:
+ssl-cert:x:112:
+lpadmin:x:113:anandms
+lightdm:x:114:
+nopasswdlogin:x:115:
+ssh:x:116:
+whoopsie:x:117:
+mlocate:x:118:
+avahi-autoipd:x:119:
+avahi:x:120:
+bluetooth:x:121:
+scanner:x:122:saned
+colord:x:123:
+pulse:x:124:
+pulse-access:x:125:
+rtkit:x:126:
+saned:x:127:
+anandms:x:1000:
+sambashare:x:128:anandms
+msanand:x:1001:

gshadow.txt

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+daemon:*::
+bin:*::
+sys:*::
+adm:*::syslog,anandms
+tty:*::
+disk:*::
+lp:*::
+mail:*::
+news:*::
+uucp:*::
+man:*::
+proxy:*::
+kmem:*::
+dialout:*::
+fax:*::
+voice:*::
+cdrom:*::anandms
+floppy:*::
+tape:*::
+sudo:*::anandms
+audio:*::pulse
+dip:*::anandms
+www-data:*::
+backup:*::
+operator:*::
+list:*::
+irc:*::
+src:*::
+gnats:*::
+shadow:*::
+utmp:*::
+video:*::
+sasl:*::
+plugdev:*::anandms
+staff:*::
+games:*::
+users:*::
+nogroup:*::
+systemd-journal:!::
+systemd-timesync:!::
+systemd-network:!::
+systemd-resolve:!::
+systemd-bus-proxy:!::
+input:!::
+crontab:!::
+syslog:!::
+netdev:!::
+messagebus:!::
+uuidd:!::
+ssl-cert:!::
+lpadmin:!::anandms
+lightdm:!::
+nopasswdlogin:!::
+ssh:!::
+whoopsie:!::
+mlocate:!::
+avahi-autoipd:!::
+avahi:!::
+bluetooth:!::
+scanner:!::saned
+colord:!::
+pulse:!::
+pulse-access:!::
+rtkit:!::
+saned:!::
+anandms:!::
+sambashare:!::anandms
+msanand:!::

makefile.mak

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+delgroup.exe:server1.o client.o
+				gcc  server1.c client.c
+server1.o:server1.c
+				gcc  -c server1.c
+client.o:client.c server.h
+				gcc -c client.c

server.h

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+void delgroupGname(char deletinggroup[]);

server1.c

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+#include<stdio.h>
+#include<stdlib.h>
+#include<string.h>
+#include "server.h"
+#define buffsize 1000
+void delgroupGname(char deletinggroup[])//a function which deletes a group name present in group and gshadow files
+{
+    char PFILE[]="C:/Users/PAVAN KUMAR M S/Desktop/C_MiniProject/PROJECT";
+    char str[buffsize];//str=variable to store the informations in the files
+    char group[]="group.txt";                         /*declaration of the files*/
+    char gshadow[]="gshadow.txt";
+    char newgroup[]="newgroup.txt";//PFILE = C:/Users/PAVAN KUMAR M S/C_MiniProject/PROJECT/(in my computer)
+    char newgshadow[]="newgshadow.txt";
+    FILE *fp;
+    FILE *fp1;//file pointer declarations which helps in the reading writing of files
+    FILE *fp2;
+    FILE *fp3;
+    fp=fopen(group,"r");//used ton open the file
+    int l1=1;
+    while((fgets(str,buffsize,fp))!=NULL)//reads the file till it encounters null reads line by line
+    {
+        int a=strcmp(strtok(str,":"),deletinggroup);//to cut the string using specific point and adds /0 to it
+        if(!a)
+        {
+            break;
+        }
+        else
+        {
+            l1++;
+        }
+    }
+    fclose(fp);
+    fp1=fopen(gshadow,"r");
+    int l2=1;
+    while((fgets(str,buffsize,fp))!=NULL)
+    {
+        int a=strcmp(strtok(str,":"),deletinggroup);//a=used to store the output which is used for the cutting of lines
+        if(!a)
+        {
+            break;
+        }
+        else
+        {
+            l2++;
+        }
+    }
+    fclose(fp1);
+    fp=fopen(group,"r");
+    fp2=fopen(newgroup,"w");
+    char ch = fgetc(fp);
+    int temp=1;//temp=used to increment,when lines are jumped
+    while(ch!=EOF)//here writing of the file occurs to get the new file without the group name you want to delete
+    {
+        if(ch=='\n')//ch=reads every character of file
+        {
+            temp++;
+        }
+        if(temp!=l1)
+        {
+            putc(ch,fp2);
+        }
+        ch=fgetc(fp);
+    }
+    fclose(fp);//used to close the file
+    fclose(fp2);
+    fp1=fopen(gshadow,"r");
+    fp3=fopen(newgshadow,"w");
+    char ch2 = fgetc(fp1);
+    int temp1=1;
+    while(ch2!=EOF)
+    {
+        if(ch2=='\n')
+        {
+            temp1++;
+        }
+        if(temp1!=l1)
+        {
+            putc(ch2,fp3);
+        }
+        ch2=fgetc(fp1);
+    }
+    fclose(fp1);
+    fclose(fp3);
+    remove(group);//removing the file
+    rename(newgroup,group);//renaming the file
+    printf("*********************************new group file********************************\n");
+    fp=fopen(group,"r");
+    char ch4=fgetc(fp);    //printing the contents of file if necessary
+    while(ch4!=EOF)
+    {
+        printf("%c",ch4);
+        ch4=fgetc(fp);
+    }
+    printf("\n");
+    printf("********************************************************************************\n");
+    printf("\n\n\n\n");
+    remove(gshadow);
+    rename(newgshadow,gshadow);
+    printf("**********************************new gshadow file***************************\n");
+    fp1=fopen(gshadow,"r");
+    char ch3=fgetc(fp1);
+    while(ch3!=EOF)
+    {
+        printf("%c",ch3);
+        ch3=fgetc(fp1);
+    }
+    printf("\n");
+    printf("********************************************************************************\n");
+}