I made a linux module program to get rq structure in CPU like this
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <../kernel/sched/sched.h>
int init_hello(void)
{
int cpu;
for_each_online_cpu(cpu)
{
struct rq *rq = cpu_rq(cpu)
printk( KERN_ALERT "rq->curr->pid = %d", rq->curr->pid);
}
}
...
Both 'Makefile' and 'insmod hello.ko' are done, But I got a error message like this
...
[30557.012624] hello: Unknown symbol runqueues (err 0)
How can I solve this problem?
Related
I'm testing an antidebug solution with ptrace method; and i compile the program by using ndk21e cross-compile.
The problem is that it compiles successfully with gcc, but fails with ndk cross-compile.
ndk cross-compile compiles all other programs without problems
#include <stdlib.h>
#include <stdio.h>
#include<sys/ptrace.h>
#include <dlfcn.h>
#include <string.h>
int main(int argc, char **argv) {
void *handle;
long (*go)(enum __ptrace_request request, pid_t pid);
// get a handle to the library that contains 'ptrace'
handle = dlopen ("/lib/x86_64-linux-gnu/libc.so.6", RTLD_LAZY);
// reference to the dynamically-resolved function 'ptrace'
go = dlsym(handle, "ptrace");
if (go(PTRACE_TRACEME, 0) < 0) {
puts("being traced");
exit(1);
}
puts("not being traced");
// cleanup
dlclose(handle);
return 0;
}
And it shows the error like the picture as follow：
gcc compileresult and cross-compile error result
How can i solve this problem. Thanks.
my vm system is ubuntu 16.04, and i have download the kernel header files,i have write the code，but don't know how to edit gcc code or Makefile
#include <linux/netdevice.h>
#include <stdio.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <netinet/in.h>
int main(){
struct net_device *dev = dev_base;
struct in_device *mydevice;
struct in_ifaddr *myifaddr;
while( dev != NULL ){
printf("dev name: %s\n", dev->name);
mydevice = dev->ip_ptr;
myifaddr = mydevice->ifa_list;
while(myifaddr != NULL){
printf("ip: %s\n", inet_ntoa((struct in_addr)(myifaddr->ifa_local)));
myifaddr = myifaddr->ifa_next;
}
dev = dev->next;
}
return 0;
}
if i use gcc test.c it will come out some error like this
yq#ubuntu:~/test$ gcc test.c
In file included from /usr/include/linux/netdevice.h:28:0,
from test.c:1:
/usr/include/linux/if.h:234:19: error: field ‘ifru_addr’ has incomplete type
struct sockaddr ifru_addr;
^
......
test.c: In function ‘main’:
test.c:8:27: error: ‘dev_base’ undeclared (first use in this function)
struct net_device *dev = dev_base;
I try to use setsockopt with the flag IPT_SO_SET_REPLACE but i keep getting the wired error from errno Protocol not available this is my code:
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sched.h>
#include <linux/sched.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <linux/netlink.h>
#include <unistd.h>
#include <sys/ptrace.h>
#include <netinet/in.h>
#include <net/if.h>
#include <linux/netfilter_ipv4/ip_tables.h>
#include <fcntl.h>
int main(void) {
int sock;
int ret;
void *data;
size_t size;
struct ipt_replace *repl;
sock = socket(PF_INET, SOCK_RAW, IPPROTO_RAW);
if (sock == -1) {
perror("socket");
return -1;
}
size = sizeof(struct ipt_replace);
data = malloc(size); Protocol not available
if (data == NULL) {
perror("malloc");
return -1;
}
memset(data, 0, size);
repl = (struct ipt_replace *) data;
repl->num_counters = 0x1;
repl->size = 0xffffffff;
repl->valid_hooks = 0x1;
repl->num_entries = 0x1;
ret = setsockopt(sock, SOL_IP, IPT_SO_SET_REPLACE, (void *) data, size);
printf("\ndone %d\n", ret);
perror("error: ");
return 0;
}
this is the output :
sock:3
data:
size:92
done -1
error: : Protocol not available
Looking briefly at the kernel code, this would seem to indicate that the IP tables module isn't available (i.e. the kernel wasn't built with it configured, or it can't be found or loaded).
It appears to me that for a socket of the kind you created, the code flow is:
enter raw_setsockopt: level != SOL_RAW so...
call ip_setsockopt: level == SOL_IP but option isn't any of the IP_xxx options so...
call nf_setsockopt: Search loaded netfilter modules for one that has registered IPT_SO_SET_REPLACE.
I think the last must have failed, so you get ENOPROTOOPT back (== Protocol not available)
I was reading about ptrace on the net and found that a process can request to trace another process by using PTRACE_ATTACH but apparently all the examples available involve the use of fork().
What I want is to have 2 programs - prg1.c and prg2.c where prg2.c should trace prg1.c. I tried using PTRACE_ATTACH in prg2.c but it seems that the call failed - prg2.c couldn't trace prg1.c . How does ptrace work ? Can anybody explain ?
Code for prg1.c :
#include <stdio.h>
#include <sys/ptrace.h>
#include <unistd.h>
#include <stdlib.h>
int main()
{
printf("Hello world\n");
sleep(20);
execl("/bin/ls", "ls", NULL);
return 0;
}
Code for prg2.c :
#include <stdio.h>
#include <sys/ptrace.h>
#include <unistd.h>
#include <stdlib.h>
int main(int argc , char **argv)
{
int pid = atoi(argv[1]);
int status;
if (ptrace(PTRACE_ATTACH, pid, NULL, NULL) == -1) {
printf("ptrace attach failed!");
return 0;
}
wait(&status);
sleep(5);
ptrace(PTRACE_DETACH, pid, NULL, NULL);
return 0;
}
I have included a sleep() to get the pid of prg1's executable(during that time) using ps -af and give it as an input to the executable of prg2.
Ive written the following echo server using UDP but i have no idea that why it is giving me Segmentation Fault in sendto function, it receives fine but has problem sending data back to client. Ive been trying to find the problem for a few hours now but got no where. Can somebody please point out the fault or what i may be doing wrong.
Thanks
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#define true 1
#define false 0
int main(int argc,char **args)
{
int BUF_LENGTH=101;
int port_no=1800;
struct sockaddr_in serv_addr,rmt_addr;
//rmt_addr=malloc(sizeof(struct sockaddr_in));
char *buffer=malloc(BUF_LENGTH);
int byte_recv=0;
int rmt_length=0;
int sock_id;
sock_id=socket(AF_INET,SOCK_DGRAM,0);
if(sock_id<0)
{
printf("Error creating socket : %d",sock_id);
return -1;
}
serv_addr.sin_family=AF_INET;
serv_addr.sin_port=htons(port_no);
serv_addr.sin_addr.s_addr=inet_addr("127.0.0.1");
bind(sock_id,(struct sockaddr*)&serv_addr,sizeof(serv_addr));
printf("Created\n");
while(true)
{
printf("Waiting\n");
byte_recv=recvfrom(sock_id,buffer,BUF_LENGTH,0,(struct sockaddr*)&rmt_addr,&rmt_length);
printf("%s\n",buffer);
if(byte_recv<0)
{
printf("Error receiving: %d",byte_recv);
error("recvfrom");
return -2;
}
printf("%d:%d %s\n",rmt_length,rmt_addr.sin_port,inet_ntoa(rmt_addr.sin_addr));
byte_recv=sendto(sock_id,buffer,BUF_LENGTH,0,(struct sockaddr*)&rmt_addr,rmt_length); //The segmentation fault comes here
printf("Bytes sent: %d \n",byte_recv);
if(byte_recv<0)
error("sendto");
}
free(buffer);
return 0;
}
These lines:
error("recvfrom");
error("sendto");
don't do what you think they do. You probably meant to say perror.
Additionally, you aren't initializing rmt_length correctly. Try this:
int rmt_length=sizeof(rmt_addr);
Finally, you are echoing more bytes back than the server receives. Try this:
byte_recv=sendto(sock_id,buffer,byte_recv,0,(struct sockaddr*)&rmt_addr,rmt_length);