__NR_mmap2 in FreeBSD
Maninya M
maninya at gmail.com
Mon Mar 26 17:56:09 UTC 2012
I am trying to convert a function written for Linux to FreeBSD.
What is the equivalent of the __NR_mmap2 system call in FreeBSD?
I keep getting the error because of this exception:
warn("Wanted space at address 0x%.8x, mmap2 system call returned 0x%.8x.
This could be a problem.",addr,temp_regs.eax);
I changed
temp_regs.eax = __NR_mmap2;
to
temp_regs.eax = 192;
but it didn't work. I suppose I couldn't understand this function. Please
help.
This is the function:
void map_memory(unsigned long addr, unsigned long size, int flags)
{
int status;
struct user_regs_struct regs,temp_regs;
unsigned long int_instr = 0x000080cd; /* INT 0x80 */
if (ptrace(PTRACE_GETREGS,exec_pid,NULL,®s) < 0)
die_perror("ptrace(PTRACE_GETREGS,%d,NULL,®s)",exec_pid);
/* mmap2 system call seems to take arguments as follows:
* eax = __NR_mmap2
* ebx = (unsigned long) page aligned address
* ecx = (unsigned long) page aligned file size
* edx = protection
* esi = flags
* Other arguments (fd and pgoff) are not required for anonymous mapping
*/
temp_regs = regs;
temp_regs.eax = __NR_mmap2;
temp_regs.ebx = addr;
temp_regs.ecx = size;
temp_regs.edx = flags;
temp_regs.esi = MAP_PRIVATE | MAP_ANONYMOUS;
temp_regs.eip = temp_regs.esp - 4;
if (ptrace(PTRACE_POKETEXT,exec_pid,(void
*)(temp_regs.eip),(void*)int_instr) < 0)
die_perror("ptrace(PTRACE_POKETEXT,%d,0x%.8x,INT 0x80) failed while
allocating memory",exec_pid,temp_regs.eip);
if (ptrace(PTRACE_SETREGS,exec_pid,NULL,&temp_regs) < 0) {
die_perror("ptrace(PTRACE_SETREGS,%d,...) failed while allocating
memory",exec_pid);
}
if (ptrace(PTRACE_SINGLESTEP,exec_pid,NULL,NULL) < 0)
die_perror("ptrace(PTRACE_SINGLESTEP,...) failed while executing
mmap2");
wait(&status);
if (WIFEXITED(status))
die("Restarted process abrubtly (exited with value %d). Aborting
Restart.",WEXITSTATUS(status));
else if (WIFSIGNALED(status))
die("Restarted process abrubtly exited because of uncaught signal (%d).
Aborting Restart.",WTERMSIG(status));
if (ptrace(PTRACE_GETREGS,exec_pid,NULL,&temp_regs) < 0) {
die_perror("ptrace(PTRACE_GETREGS,...) failed after executing mmap2
system call");
}
if (temp_regs.eax != addr)
warn("Wanted space at address 0x%.8x, mmap2 system call returned
0x%.8x. This could be a problem.",addr,temp_regs.eax);
else if (cr_options.verbose)
fprintf(stdout,"Successfully allocated [0x%.8lx -
0x%.8lx]\n",addr,addr+size);
/* Restore original registers */
if (ptrace(PTRACE_SETREGS,exec_pid,NULL,®s) < 0) {
die_perror("ptrace(PTRACE_SETREGS,...) when restoring registering after
allocating memory (mmap2)");
}
}
--
Maninya
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