grpkill initial commit

.gitignore

@@ -0,0 +1,2 @@
+grpkill
+grpkill-*

Makefile

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+CC = gcc
+
+# compiler flags:
+#  -g    adds debugging information to the executable file
+#  -Wall turns on most, but not all, compiler warnings
+CFLAGS  = -g -Wall
+CFLAGS_PROD  = -s -Wall
+
+# the build target executable:
+TARGET = grpkill
+
+all: $(TARGET)
+
+$(TARGET): $(TARGET).c
+	$(CC) $(CFLAGS) -o $(TARGET) $(TARGET).c
+
+$(TARGET)-prod: $(TARGET).c
+	$(CC) $(CFLAGS_PROD) -o $(TARGET)-prod $(TARGET).c
+
+clean:
+	$(RM) $(TARGET)
+

grpkill.c

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+#define _GNU_SOURCE
+
+#include <sys/types.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <grp.h>
+#include <sys/stat.h>
+#include <stdlib.h>
+#include <signal.h>
+
+
+int main(int argc, char * argv[]){
+	int targetpid;
+	int targetgid;
+	char* procplace;
+	struct stat st;
+	if (argc != 2){
+		fprintf(stderr, "error - require exactly 1 argument\n");
+		return 1;
+	}
+	if (sscanf(argv[1], "%i", &targetpid) != 1) {
+		fprintf(stderr, "error - argv[1] not an integer\n");
+		return 2;
+	}
+	
+	if (group_member(getegid()) == 0) {
+		fprintf(stderr, "error - User is not part of the egid group %d\n", getegid());
+		return 3;
+	}
+	// todo check if pid exists
+
+	procplace = (char*) malloc(16*sizeof(char));
+	
+	sprintf(procplace, "/proc/%d", targetpid);
+	stat(procplace, &st);
+	targetgid = st.st_gid;
+	free(procplace);
+	
+	printf("pid: %d gid: %d\n", targetpid, targetgid);
+	procplace = NULL;
+
+	if (targetgid != getegid()){
+		fprintf(stderr, "error - target gid is not equal to our egid. %d != %d\n", targetgid, getegid());	
+		return 4;
+	}
+	printf("Killing %d\n", targetpid);
+	kill(targetpid, SIGTERM);
+}