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Refactor tamper_with_syscall_exiting()

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Move the code than deals with updating the return and error values
to separate functions.

* syscall.c (set_error, set_success): New functions.
(tamper_with_syscall_exiting): Use them.
This commit is contained in:
Дмитрий Левин 2018-12-05 16:10:05 +00:00
parent 51d89ef0a0
commit 217eccfba5
1 changed files with 38 additions and 32 deletions
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70
syscall.c
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@ -478,7 +478,9 @@ static long get_regs(struct tcb *);
static int get_syscall_args(struct tcb *);
static int get_syscall_result(struct tcb *);
static void get_error(struct tcb *, bool);
static int arch_get_scno(struct tcb *tcp);
static void set_error(struct tcb *, unsigned long);
static void set_success(struct tcb *, kernel_long_t);
static int arch_get_scno(struct tcb *);
static int arch_set_scno(struct tcb *, kernel_ulong_t);
static int arch_get_syscall_args(struct tcb *);
static void arch_get_error(struct tcb *, bool);
@ -564,37 +566,10 @@ tamper_with_syscall_exiting(struct tcb *tcp)
return 1;
}
bool update_tcb = false;
if (opts->data.flags & INJECT_F_RETVAL) {
kernel_long_t inject_rval =
retval_get(opts->data.rval_idx);
kernel_long_t u_rval = tcp->u_rval;
tcp->u_rval = inject_rval;
if (arch_set_success(tcp)) {
tcp->u_rval = u_rval;
} else {
update_tcb = true;
tcp->u_error = 0;
}
} else {
unsigned long new_error = retval_get(opts->data.rval_idx);
if (new_error != tcp->u_error && new_error <= MAX_ERRNO_VALUE) {
unsigned long u_error = tcp->u_error;
tcp->u_error = new_error;
if (arch_set_error(tcp)) {
tcp->u_error = u_error;
} else {
update_tcb = true;
}
}
}
if (update_tcb)
get_error(tcp, !(tcp->s_ent->sys_flags & SYSCALL_NEVER_FAILS));
if (opts->data.flags & INJECT_F_RETVAL)
set_success(tcp, retval_get(opts->data.rval_idx));
else
set_error(tcp, retval_get(opts->data.rval_idx));
return 0;
}
@ -1302,6 +1277,37 @@ get_error(struct tcb *tcp, const bool check_errno)
arch_get_error(tcp, check_errno);
}
static void
set_error(struct tcb *tcp, unsigned long new_error)
{
const unsigned long old_error = tcp->u_error;
if (new_error == old_error || new_error > MAX_ERRNO_VALUE)
return;
tcp->u_error = new_error;
if (arch_set_error(tcp)) {
tcp->u_error = old_error;
/* arch_set_error does not update u_rval */
} else {
get_error(tcp, !(tcp->s_ent->sys_flags & SYSCALL_NEVER_FAILS));
}
}
static void
set_success(struct tcb *tcp, kernel_long_t new_rval)
{
const kernel_long_t old_rval = tcp->u_rval;
tcp->u_rval = new_rval;
if (arch_set_success(tcp)) {
tcp->u_rval = old_rval;
/* arch_set_error does not update u_error */
} else {
get_error(tcp, !(tcp->s_ent->sys_flags & SYSCALL_NEVER_FAILS));
}
}
#include "get_scno.c"
#include "set_scno.c"
#include "get_syscall_args.c"