Instead of extracting the user-space pointers of the 3 fd_set, we now extract the bitmask of the FDs in the sets (in, out, ex) in the form of an array of uint8_t (1024 FDs is the limit in the kernel).
In this example, we select in input FDs 5 to 19 (0xFFFF0), it returns
that one FD is ready: FD 12 (0x1000).
syscall_entry_select: {
n = 20,
_fdset_in_length = 3, fdset_in = [ [0] = 0xF0, [1] = 0xFF, [2] = 0xF ],
_fdset_out_length = 0, fdset_out = [ ],
_fdset_ex_length = 0, fdset_ex = [ ],
tvp = 0
}
syscall_exit_select: {
ret = 1,
_fdset_in_length = 3, fdset_in = [ [0] = 0x0, [1] = 0x10, [2] = 0x0 ],
_fdset_out_length = 0, fdset_out = [ ],
_fdset_ex_length = 0, fdset_ex = [ ],
tvp = 0
}
Signed-off-by: Julien Desfossez <jdesfos...@efficios.com>
---
.../syscalls/headers/syscalls_pointers_override.h | 248 +++++++++++++++++++++
1 file changed, 248 insertions(+)
diff --git a/instrumentation/syscalls/headers/syscalls_pointers_override.h
b/instrumentation/syscalls/headers/syscalls_pointers_override.h
index bf5c632..b9dd54a 100644
--- a/instrumentation/syscalls/headers/syscalls_pointers_override.h
+++ b/instrumentation/syscalls/headers/syscalls_pointers_override.h
@@ -53,4 +53,252 @@ SC_LTTNG_TRACEPOINT_EVENT(pipe2,
)
)
+#define LTTNG_SYSCALL_SELECT_locvar \
+ unsigned long *fds_in, *fds_out, *fds_ex; \
+ unsigned long nr_bytes, nr_ulong; \
+ uint8_t overflow;
+
+#define LTTNG_SYSCALL_SELECT_code_pre
\
+ sc_inout(
\
+ {
\
+ int err;
\
+ unsigned int n_in_bytes;
\
+
\
+ tp_locvar->fds_in = NULL;
\
+ tp_locvar->fds_out = NULL;
\
+ tp_locvar->fds_ex = NULL;
\
+ tp_locvar->overflow = 0;
\
+
\
+ sc_out(
\
+ if (ret <= 0)
\
+ goto error;
\
+ )
\
+
\
+ if (n <= 0)
\
+ goto error;
\
+
\
+ /* On error or bogus input, don't copy anything. */
\
+ if (n >__FD_SETSIZE)
\
+ goto error;
\
+
\
+ n_in_bytes = DIV_ROUND_UP((unsigned int) n, BITS_PER_BYTE);
\
+
\
+ /*
\
+ * Limit atomic memory allocation to one page, since n
\
+ * is limited to 1024 and the smallest page size on Linux
\
+ * is 4k, this should not happen, don't try to make it work.
\
+ */
\
+ if (n_in_bytes > PAGE_SIZE) {
\
+ WARN_ON_ONCE(1);
\
+ /* Inform the user that we did not output everything.
*/ \
+ tp_locvar->overflow = 1;
\
+ goto error;
\
+ } else {
\
+ tp_locvar->nr_bytes = n_in_bytes;
\
+ tp_locvar->nr_ulong = DIV_ROUND_UP(n_in_bytes,
\
+ sizeof(unsigned long));
\
+ }
\
+
\
+ if (inp) {
\
+ tp_locvar->fds_in = kmalloc(
\
+ tp_locvar->nr_ulong * sizeof(unsigned
long), \
+ GFP_ATOMIC | GFP_NOWAIT);
\
+ if (!tp_locvar->fds_in)
\
+ goto error;
\
+
\
+ err = lib_ring_buffer_copy_from_user_check_nofault(
\
+ tp_locvar->fds_in, inp,
\
+ tp_locvar->nr_ulong * sizeof(unsigned
long)); \
+ if (err != 0)
\
+ goto error;
\
+ }
\
+ if (outp) {
\
+ tp_locvar->fds_out = kmalloc(
\
+ tp_locvar->nr_ulong * sizeof(unsigned
long), \
+ GFP_ATOMIC | GFP_NOWAIT);
\
+ if (!tp_locvar->fds_out)
\
+ goto error;
\
+
\
+ err = lib_ring_buffer_copy_from_user_check_nofault(
\
+ tp_locvar->fds_out, outp,
\
+ tp_locvar->nr_ulong * sizeof(unsigned
long)); \
+ if (err != 0)
\
+ goto error;
\
+ }
\
+ if (exp) {
\
+ tp_locvar->fds_ex = kmalloc(
\
+ tp_locvar->nr_ulong * sizeof(unsigned
long), \
+ GFP_ATOMIC | GFP_NOWAIT);
\
+ if (!tp_locvar->fds_ex)
\
+ goto error;
\
+
\
+ err = lib_ring_buffer_copy_from_user_check_nofault(
\
+ tp_locvar->fds_ex, exp,
\
+ tp_locvar->nr_ulong * sizeof(unsigned
long)); \
+ if (err != 0)
\
+ goto error;
\
+ }
\
+ goto end;
\
+
\
+error:
\
+ tp_locvar->nr_bytes = 0;
\
+ tp_locvar->nr_ulong = 0;
\
+end: ; /* Label at end of compound statement. */
\
+ }
\
+ )
+
+#define LTTNG_SYSCALL_SELECT_fds_field_LE(name, input)
\
+ ctf_custom_field(
\
+ ctf_custom_type(
\
+ .atype = atype_sequence,
\
+ .u.sequence.length_type = __type_integer(
\
+ uint8_t, 0, 0, 0, __BYTE_ORDER, 10, none),
\
+ .u.sequence.elem_type = __type_integer(uint8_t, 0, 0,
0, \
+ __BYTE_ORDER, 16, none),
\
+ ),
\
+ name,
\
+ ctf_custom_code(
\
+ unsigned int src;
\
+ unsigned int nr_bytes_out = 0;
\
+
\
+ if (input) {
\
+ ctf_integer_type(uint8_t, tp_locvar->nr_bytes)
\
+ ctf_align(uint8_t)
\
+ } else {
\
+ ctf_integer_type(uint8_t, 0)
\
+ ctf_align(uint8_t)
\
+ goto skip_##name;
\
+ }
\
+
\
+ for (src = 0; src < tp_locvar->nr_ulong; src++) {
\
+ int dst;
\
+ for (dst = 0; dst < sizeof(long); dst++) {
\
+ if (nr_bytes_out++ >=
tp_locvar->nr_bytes) { \
+ goto skip_##name;
\
+ }
\
+ ctf_user_integer_type(uint8_t,
\
+ ((uint8_t __user *)
(input->fds_bits + src))[dst]); \
+ }
\
+ }
\
+ skip_##name: ;
\
+ )
\
+ )
+
+#define LTTNG_SYSCALL_SELECT_fds_field_BE(name, input)
\
+ ctf_custom_field(
\
+ ctf_custom_type(
\
+ .atype = atype_sequence,
\
+ .u.sequence.length_type = __type_integer(
\
+ uint8_t, 0, 0, 0, __BYTE_ORDER, 10, none),
\
+ .u.sequence.elem_type = __type_integer(uint8_t, 0, 0,
0, \
+ __BYTE_ORDER, 16, none),
\
+ ),
\
+ name,
\
+ ctf_custom_code(
\
+ unsigned int src;
\
+ unsigned int nr_bytes_out = 0;
\
+
\
+ if (input) {
\
+ ctf_integer_type(uint8_t, tp_locvar->nr_bytes)
\
+ ctf_align(uint8_t)
\
+ } else {
\
+ ctf_integer_type(uint8_t, 0)
\
+ ctf_align(uint8_t)
\
+ goto skip_##name;
\
+ }
\
+
\
+ for (src = 0; src < tp_locvar->nr_ulong; src++) {
\
+ int dst;
\
+ for (dst = sizeof(long); dst >= 0; dst--) {
\
+ if (nr_bytes_out++ >=
tp_locvar->nr_bytes) { \
+ goto skip_##name;
\
+ }
\
+ ctf_user_integer_type(uint8_t,
\
+ ((uint8_t __user *)
(input->fds_bits + src))[dst]); \
+ }
\
+ }
\
+ skip_##name: ;
\
+ )
\
+ )
+
+#define LTTNG_SYSCALL_SELECT_code_post \
+ kfree(tp_locvar->fds_in); \
+ kfree(tp_locvar->fds_out); \
+ kfree(tp_locvar->fds_ex);
+
+#if defined(CONFIG_X86_32) || defined(CONFIG_X86_64)
+#define OVERRIDE_32_select
+#define OVERRIDE_64_select
+SC_LTTNG_TRACEPOINT_EVENT_CODE(select,
+ TP_PROTO(sc_exit(long ret,) int n, fd_set __user *inp, fd_set __user
*outp,
+ fd_set __user *exp, struct timeval *tvp),
+ TP_ARGS(sc_exit(ret,) n, inp, outp, exp, tvp),
+ TP_locvar(
+ LTTNG_SYSCALL_SELECT_locvar
+ ),
+ TP_code_pre(
+ LTTNG_SYSCALL_SELECT_code_pre
+ ),
+ TP_FIELDS(
+ sc_exit(ctf_integer(long, ret, ret))
+ sc_in(ctf_integer(int, n, n))
+ sc_inout(ctf_integer(uint8_t, overflow, tp_locvar->overflow))
+ sc_inout(ctf_integer(struct timeval *, tvp, tvp))
+
+ sc_inout(
+#if (__BYTE_ORDER == __LITTLE_ENDIAN)
+ LTTNG_SYSCALL_SELECT_fds_field_LE(readfds, inp)
+ LTTNG_SYSCALL_SELECT_fds_field_LE(writefds, outp)
+ LTTNG_SYSCALL_SELECT_fds_field_LE(exceptfds, exp)
+#else
+ LTTNG_SYSCALL_SELECT_fds_field_BE(readfds, inp)
+ LTTNG_SYSCALL_SELECT_fds_field_BE(writefds, outp)
+ LTTNG_SYSCALL_SELECT_fds_field_BE(exceptfds, exp)
+#endif
+ )
+ ),
+ TP_code_post(
+ LTTNG_SYSCALL_SELECT_code_post
+ )
+)
+#endif /* defined(CONFIG_X86_32) || defined(CONFIG_X86_64) */
+
+#if defined(CONFIG_X86_32) || defined(CONFIG_X86_64) || defined(CONFIG_ARM64)
|| defined(CONFIG_ARM)
+#define OVERRIDE_32_pselect6
+#define OVERRIDE_64_pselect6
+SC_LTTNG_TRACEPOINT_EVENT_CODE(pselect6,
+ TP_PROTO(sc_exit(long ret,) int n, fd_set __user * inp, fd_set __user *
outp,
+ fd_set __user * exp, struct timeval __user * tvp, void __user *
sig),
+ TP_ARGS(sc_exit(ret,) n, inp, outp, exp, tvp, sig),
+ TP_locvar(
+ LTTNG_SYSCALL_SELECT_locvar
+ ),
+ TP_code_pre(
+ LTTNG_SYSCALL_SELECT_code_pre
+ ),
+ TP_FIELDS(
+ sc_exit(ctf_integer(long, ret, ret))
+ sc_in(ctf_integer(int, n, n))
+ sc_inout(ctf_integer(uint8_t, overflow, tp_locvar->overflow))
+ sc_inout(ctf_integer(struct timeval *, tvp, tvp))
+ sc_in(ctf_integer_hex(void *, sig, sig))
+
+ sc_inout(
+#if (__BYTE_ORDER == __LITTLE_ENDIAN)
+ LTTNG_SYSCALL_SELECT_fds_field_LE(readfds, inp)
+ LTTNG_SYSCALL_SELECT_fds_field_LE(writefds, outp)
+ LTTNG_SYSCALL_SELECT_fds_field_LE(exceptfds, exp)
+#else
+ LTTNG_SYSCALL_SELECT_fds_field_BE(readfds, inp)
+ LTTNG_SYSCALL_SELECT_fds_field_BE(writefds, outp)
+ LTTNG_SYSCALL_SELECT_fds_field_BE(exceptfds, exp)
+#endif
+ )
+ ),
+ TP_code_post(
+ LTTNG_SYSCALL_SELECT_code_post
+ )
+)
+#endif /* defined(CONFIG_X86_32) || defined(CONFIG_X86_64) ||
defined(CONFIG_ARM64) || defined(CONFIG_ARM) */
+
#endif /* CREATE_SYSCALL_TABLE */
--
1.9.1
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