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Implement signal injection

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This extends the fault injection capability with :signal=SIG option
which injects a signal on entering each syscall from the specified set.

:signal and :error options are complementary, if they are both specified
the syscall will be fault injected as usual and the specified signal
will be delivered to the tracee.

* defs.h (struct fault_opts): Change the type of err field to int16_t,
add signo field.
(trace_syscall): Add a pointer argument.
* qualify.c: Include "nsig.h".
(parse_fault_token): Handle signal= option.
(qualify_fault): Update default fault_opts.
* strace.c (trace): Forward signal number from trace_syscall
to ptrace_restart(PTRACE_SYSCALL).
* syscall.c (inject_syscall_fault_entering): Add pointer argument,
save there the signal number specified by fault options.  Do not inject
a syscall fault unless instructed by fault options.
(update_syscall_fault_exiting): Update the error code injection check.
(trace_syscall_entering): Add pointer argument, forward it to
inject_syscall_fault_entering.
(trace_syscall): Add pointer argument, forward it to
trace_syscall_entering.

Signed-off-by: Seraphime Kirkovski <kirkseraph@gmail.com>
Signed-off-by: Dmitry V. Levin <ldv@altlinux.org>
This commit is contained in:
Seraphime Kirkovski 2016-12-27 12:14:06 +01:00 committed by Dmitry V. Levin
parent 22894ccff6
commit a864a32a76
4 changed files with 29 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
defs.h
View File

@ -217,7 +217,8 @@ typedef struct ioctlent {
struct fault_opts {
uint16_t first;
uint16_t step;
uint16_t err;
int16_t err;
uint16_t signo;
};
/* Trace Control Block */
@ -439,7 +440,7 @@ extern int read_int_from_file(const char *, int *);
extern void set_sortby(const char *);
extern void set_overhead(int);
extern void print_pc(struct tcb *);
extern int trace_syscall(struct tcb *);
extern int trace_syscall(struct tcb *, unsigned int *);
extern void count_syscall(struct tcb *, const struct timeval *);
extern void call_summary(FILE *);

15
qualify.c
View File

@ -26,6 +26,7 @@
*/
#include "defs.h"
#include "nsig.h"
typedef unsigned int number_slot_t;
#define BITS_PER_SLOT (sizeof(number_slot_t) * 8)
@ -414,6 +415,11 @@ parse_fault_token(const char *const token, struct fault_opts *const fopts)
if (intval < 1)
return false;
fopts->err = intval;
} else if ((val = strip_prefix("signal=", token))) {
intval = sigstr_to_uint(val);
if (intval < 1 || intval > NSIG_BYTES * 8)
return false;
fopts->signo = intval;
} else {
return false;
}
@ -494,7 +500,8 @@ qualify_fault(const char *const str)
struct fault_opts opts = {
.first = 1,
.step = 1,
.err = 0
.err = -1,
.signo = 0
};
char *buf = NULL;
char *name = parse_fault_expression(str, &buf, &opts);
@ -502,6 +509,12 @@ qualify_fault(const char *const str)
error_msg_and_die("invalid %s '%s'", "fault argument", str);
}
/*
* If neither error nor signal is specified,
* fallback to the default platform error code.
*/
if (opts.signo == 0 && opts.err == -1)
opts.err = 0;
struct number_set tmp_set[SUPPORTED_PERSONALITIES];
memset(tmp_set, 0, sizeof(tmp_set));

4
strace.c
View File

@ -2447,7 +2447,8 @@ show_stopsig:
* This should be syscall entry or exit.
* Handle it.
*/
if (trace_syscall(tcp) < 0) {
sig = 0;
if (trace_syscall(tcp, &sig) < 0) {
/*
* ptrace() failed in trace_syscall().
* Likely a result of process disappearing mid-flight.
@ -2461,6 +2462,7 @@ show_stopsig:
*/
return true;
}
goto restart_tracee;
restart_tracee_with_sig_0:
sig = 0;

16
syscall.c
View File

@ -568,7 +568,7 @@ tcb_fault_opts(struct tcb *tcp)
static long
inject_syscall_fault_entering(struct tcb *tcp)
inject_syscall_fault_entering(struct tcb *tcp, unsigned int *signo)
{
if (!tcp->fault_vec[current_personality]) {
tcp->fault_vec[current_personality] =
@ -590,7 +590,9 @@ inject_syscall_fault_entering(struct tcb *tcp)
opts->first = opts->step;
if (!arch_set_scno(tcp, -1))
if (opts->signo > 0)
*signo = opts->signo;
if (opts->err != -1 && !arch_set_scno(tcp, -1))
tcp->flags |= TCB_FAULT_INJ;
return 0;
@ -601,7 +603,7 @@ update_syscall_fault_exiting(struct tcb *tcp)
{
struct fault_opts *opts = tcb_fault_opts(tcp);
if (opts && opts->err && tcp->u_error != opts->err) {
if (opts && opts->err > 0 && tcp->u_error != (uint16_t) opts->err) {
unsigned long u_error = tcp->u_error;
tcp->u_error = opts->err;
if (arch_set_error(tcp))
@ -612,7 +614,7 @@ update_syscall_fault_exiting(struct tcb *tcp)
}
static int
trace_syscall_entering(struct tcb *tcp)
trace_syscall_entering(struct tcb *tcp, unsigned int *sig)
{
int res, scno_good;
@ -683,7 +685,7 @@ trace_syscall_entering(struct tcb *tcp)
}
if (tcp->qual_flg & QUAL_FAULT)
inject_syscall_fault_entering(tcp);
inject_syscall_fault_entering(tcp, sig);
if (cflag == CFLAG_ONLY_STATS) {
res = 0;
@ -962,10 +964,10 @@ trace_syscall_exiting(struct tcb *tcp)
}
int
trace_syscall(struct tcb *tcp)
trace_syscall(struct tcb *tcp, unsigned int *signo)
{
return exiting(tcp) ?
trace_syscall_exiting(tcp) : trace_syscall_entering(tcp);
trace_syscall_exiting(tcp) : trace_syscall_entering(tcp, signo);
}
bool