[lttng-dev] [PATCH lttng-modules v5 2/5] Extract the FD sets in select and pselect6
Julien Desfossez
jdesfossez at efficios.com
Sat Apr 23 00:16:49 UTC 2016
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 <jdesfossez at efficios.com>
---
.../syscalls/headers/syscalls_pointers_override.h | 510 +++++++++++++++++++++
1 file changed, 510 insertions(+)
diff --git a/instrumentation/syscalls/headers/syscalls_pointers_override.h b/instrumentation/syscalls/headers/syscalls_pointers_override.h
index bf5c632..ef4dc1c 100644
--- a/instrumentation/syscalls/headers/syscalls_pointers_override.h
+++ b/instrumentation/syscalls/headers/syscalls_pointers_override.h
@@ -53,4 +53,514 @@ SC_LTTNG_TRACEPOINT_EVENT(pipe2,
)
)
+#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(
+ unsigned long *fds_in, *fds_out, *fds_ex;
+ unsigned long nr_bytes, nr_ulong;
+ unsigned int overflow;
+ ),
+ TP_code_pre(
+ sc_inout(
+ {
+ int err;
+
+ 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;
+
+ /* Limit atomic memory allocation to one page */
+ if (DIV_ROUND_UP((unsigned int) n, BITS_PER_BYTE) > PAGE_SIZE) {
+ tp_locvar->nr_bytes = PAGE_SIZE;
+ tp_locvar->nr_ulong = PAGE_SIZE / sizeof(unsigned long);
+ /* Inform the user that we did not output everything. */
+ tp_locvar->overflow = 1;
+ } else {
+ tp_locvar->nr_bytes = DIV_ROUND_UP((unsigned int) n, BITS_PER_BYTE);
+ tp_locvar->nr_ulong = DIV_ROUND_UP((unsigned int) n,
+ BITS_PER_BYTE * sizeof(unsigned long));
+ }
+ /* On error or bogus input, don't copy anything. */
+ if (tp_locvar->nr_bytes > (__FD_SETSIZE / (8 * sizeof(uint8_t)))) {
+ goto error;
+ }
+
+ if (inp) {
+ tp_locvar->fds_in = kmalloc(
+ tp_locvar->nr_ulong * sizeof(unsigned long),
+ GFP_ATOMIC);
+ 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);
+ 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);
+ 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:
+ /* bypass error: label at end of compound statement */
+ ;
+ }
+ )
+ ),
+ TP_FIELDS(
+ sc_exit(ctf_integer(long, ret, ret))
+ sc_in(ctf_integer(int, n, n))
+ sc_inout(ctf_integer(int, overflow, tp_locvar->overflow))
+ sc_inout(ctf_integer(struct timeval *, tvp, tvp))
+
+ sc_inout(
+ /* inp */
+ ctf_custom_field(
+ ctf_custom_type(
+ .atype = atype_sequence,
+ .u.sequence.length_type = __type_integer(
+ uint16_t, 0, 0, 0, __BYTE_ORDER, 10, none),
+ .u.sequence.elem_type = __type_integer(uint8_t, 0, 0, 0,
+ __BYTE_ORDER, 16, none),
+ ),
+ readfds,
+ ctf_custom_code(
+ unsigned int src;
+ unsigned int nr_bytes_out = 0;
+
+ if (inp) {
+ ctf_integer_type(uint16_t, tp_locvar->nr_bytes)
+ ctf_align(uint8_t)
+ } else {
+ ctf_integer_type(uint16_t, 0)
+ ctf_align(uint8_t)
+ goto skip_inp;
+ }
+
+ for (src = 0; src < tp_locvar->nr_ulong; src++) {
+ int dst;
+#if (__BYTE_ORDER == __LITTLE_ENDIAN)
+ for (dst = 0; dst < sizeof(long); dst++) {
+ ctf_user_integer_type(uint8_t,
+ ((uint8_t __user *) (inp->fds_bits + src))[dst]);
+ if (++nr_bytes_out >= tp_locvar->nr_bytes) {
+ goto skip_inp;
+ }
+ }
+#else
+ for (dst = sizeof(long); dst >= 0; dst--) {
+ ctf_user_integer_type(uint8_t,
+ ((uint8_t __user *) (inp->fds_bits + src))[dst]);
+ if (++nr_bytes_out >= tp_locvar->nr_bytes) {
+ goto skip_inp;
+ }
+ }
+#endif
+ }
+ skip_inp:
+ ;
+ )
+ )
+ /* outp */
+ ctf_custom_field(
+ ctf_custom_type(
+ .atype = atype_sequence,
+ .u.sequence.length_type = __type_integer(
+ uint16_t, 0, 0, 0, __BYTE_ORDER, 10, none),
+ .u.sequence.elem_type = __type_integer(uint8_t, 0, 0, 0,
+ __BYTE_ORDER, 16, none),
+ ),
+ writefds,
+ ctf_custom_code(
+ unsigned int src;
+ unsigned int nr_bytes_out = 0;
+
+ if (outp) {
+ ctf_integer_type(uint16_t, tp_locvar->nr_bytes)
+ ctf_align(uint8_t)
+ } else {
+ ctf_integer_type(uint16_t, 0)
+ ctf_align(uint8_t)
+ goto skip_outp;
+ }
+
+ for (src = 0; src < tp_locvar->nr_ulong; src++) {
+ int dst;
+#if (__BYTE_ORDER == __LITTLE_ENDIAN)
+ for (dst = 0; dst < sizeof(long); dst++) {
+ ctf_user_integer_type(uint8_t,
+ ((uint8_t __user *) (outp->fds_bits + src))[dst]);
+ if (++nr_bytes_out >= tp_locvar->nr_bytes) {
+ goto skip_outp;
+ }
+ }
+#else
+ for (dst = sizeof(long); dst >= 0; dst--) {
+ ctf_user_integer_type(uint8_t,
+ ((uint8_t __user *) (outp->fds_bits + src))[dst]);
+ if (++nr_bytes_out >= tp_locvar->nr_bytes) {
+ goto skip_outp;
+ }
+ }
+#endif
+ }
+ skip_outp:
+ ;
+ )
+ )
+ /* exp */
+ ctf_custom_field(
+ ctf_custom_type(
+ .atype = atype_sequence,
+ .u.sequence.length_type = __type_integer(
+ uint16_t, 0, 0, 0, __BYTE_ORDER, 10, none),
+ .u.sequence.elem_type = __type_integer(uint8_t, 0, 0, 0,
+ __BYTE_ORDER, 16, none),
+ ),
+ exceptfds,
+ ctf_custom_code(
+ unsigned int src;
+ unsigned int nr_bytes_out = 0;
+
+ if (exp) {
+ ctf_integer_type(uint16_t, tp_locvar->nr_bytes)
+ ctf_align(uint8_t)
+ } else {
+ ctf_integer_type(uint16_t, 0)
+ ctf_align(uint8_t)
+ goto skip_exp;
+ }
+
+ for (src = 0; src < tp_locvar->nr_ulong; src++) {
+ int dst;
+#if (__BYTE_ORDER == __LITTLE_ENDIAN)
+ for (dst = 0; dst < sizeof(long); dst++) {
+ ctf_user_integer_type(uint8_t,
+ ((uint8_t __user *) (exp->fds_bits + src))[dst]);
+ if (++nr_bytes_out >= tp_locvar->nr_bytes) {
+ goto skip_exp;
+ }
+ }
+#else
+ for (dst = sizeof(long); dst >= 0; dst--) {
+ ctf_user_integer_type(uint8_t,
+ ((uint8_t __user *) (exp->fds_bits + src))[dst]);
+ if (++nr_bytes_out >= tp_locvar->nr_bytes) {
+ goto skip_exp;
+ }
+ }
+#endif
+ }
+ skip_exp:
+ ;
+ )
+ )
+ )
+ ),
+ TP_code_post(
+ kfree(tp_locvar->fds_in);
+ kfree(tp_locvar->fds_out);
+ kfree(tp_locvar->fds_ex);
+ )
+)
+#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 * tvp, void * sig),
+ TP_ARGS(sc_exit(ret,) n, inp, outp, exp, tvp, sig),
+ TP_locvar(
+ unsigned long *fds_in, *fds_out, *fds_ex;
+ unsigned long nr_bytes, nr_ulong;
+ unsigned int overflow;
+ ),
+ TP_code_pre(
+ sc_inout(
+ {
+ int err;
+
+ 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;
+
+ /* Limit atomic memory allocation to one page */
+ if (DIV_ROUND_UP((unsigned int) n, BITS_PER_BYTE) > PAGE_SIZE) {
+ tp_locvar->nr_bytes = PAGE_SIZE;
+ tp_locvar->nr_ulong = PAGE_SIZE / sizeof(unsigned long);
+ /* Inform the user that we did not output everything. */
+ tp_locvar->overflow = 1;
+ } else {
+ tp_locvar->nr_bytes = DIV_ROUND_UP((unsigned int) n, BITS_PER_BYTE);
+ tp_locvar->nr_ulong = DIV_ROUND_UP((unsigned int) n,
+ BITS_PER_BYTE * sizeof(unsigned long));
+ }
+ /* On error or bogus input, don't copy anything. */
+ if (tp_locvar->nr_bytes > (__FD_SETSIZE / (8 * sizeof(uint8_t)))) {
+ goto error;
+ }
+
+ if (inp) {
+ tp_locvar->fds_in = kmalloc(
+ tp_locvar->nr_ulong * sizeof(unsigned long),
+ GFP_ATOMIC);
+ 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);
+ 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);
+ 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:
+ /* bypass error: label at end of compound statement */
+ ;
+ }
+ )
+ ),
+ TP_FIELDS(
+ sc_exit(ctf_integer(long, ret, ret))
+ sc_in(ctf_integer(int, n, n))
+ sc_in(ctf_integer(int, overflow, tp_locvar->overflow))
+ sc_inout(ctf_integer(struct timeval *, tvp, tvp))
+
+ sc_inout(
+ /* inp */
+ ctf_custom_field(
+ ctf_custom_type(
+ .atype = atype_sequence,
+ .u.sequence.length_type = __type_integer(
+ uint16_t, 0, 0, 0, __BYTE_ORDER, 10, none),
+ .u.sequence.elem_type = __type_integer(uint8_t, 0, 0, 0,
+ __BYTE_ORDER, 16, none),
+ ),
+ readfds,
+ ctf_custom_code(
+ unsigned int src;
+ unsigned int nr_bytes_out = 0;
+
+ if (inp) {
+ ctf_integer_type(uint16_t, tp_locvar->nr_bytes)
+ ctf_align(uint8_t)
+ } else {
+ ctf_integer_type(uint16_t, 0)
+ ctf_align(uint8_t)
+ goto skip_inp;
+ }
+
+ for (src = 0; src < tp_locvar->nr_ulong; src++) {
+ int dst;
+#if (__BYTE_ORDER == __LITTLE_ENDIAN)
+ for (dst = 0; dst < sizeof(long); dst++) {
+ ctf_user_integer_type(uint8_t,
+ ((uint8_t __user *) (inp->fds_bits + src))[dst]);
+ if (++nr_bytes_out >= tp_locvar->nr_bytes) {
+ goto skip_inp;
+ }
+ }
+#else
+ for (dst = sizeof(long); dst >= 0; dst--) {
+ ctf_user_integer_type(uint8_t,
+ ((uint8_t __user *) (inp->fds_bits + src))[dst]);
+ if (++nr_bytes_out >= tp_locvar->nr_bytes) {
+ goto skip_inp;
+ }
+ }
+#endif
+ }
+ skip_inp:
+ ;
+ )
+ )
+ /* outp */
+ ctf_custom_field(
+ ctf_custom_type(
+ .atype = atype_sequence,
+ .u.sequence.length_type = __type_integer(
+ uint16_t, 0, 0, 0, __BYTE_ORDER, 10, none),
+ .u.sequence.elem_type = __type_integer(uint8_t, 0, 0, 0,
+ __BYTE_ORDER, 16, none),
+ ),
+ writefds,
+ ctf_custom_code(
+ unsigned int src;
+ unsigned int nr_bytes_out = 0;
+
+ if (outp) {
+ ctf_integer_type(uint16_t, tp_locvar->nr_bytes)
+ ctf_align(uint8_t)
+ } else {
+ ctf_integer_type(uint16_t, 0)
+ ctf_align(uint8_t)
+ goto skip_outp;
+ }
+
+ for (src = 0; src < tp_locvar->nr_ulong; src++) {
+ int dst;
+#if (__BYTE_ORDER == __LITTLE_ENDIAN)
+ for (dst = 0; dst < sizeof(long); dst++) {
+ ctf_user_integer_type(uint8_t,
+ ((uint8_t __user *) (outp->fds_bits + src))[dst]);
+ if (++nr_bytes_out >= tp_locvar->nr_bytes) {
+ goto skip_outp;
+ }
+ }
+#else
+ for (dst = sizeof(long); dst >= 0; dst--) {
+ ctf_user_integer_type(uint8_t,
+ ((uint8_t __user *) (outp->fds_bits + src))[dst]);
+ if (++nr_bytes_out >= tp_locvar->nr_bytes) {
+ goto skip_outp;
+ }
+ }
+#endif
+ }
+ skip_outp:
+ ;
+ )
+ )
+ /* exp */
+ ctf_custom_field(
+ ctf_custom_type(
+ .atype = atype_sequence,
+ .u.sequence.length_type = __type_integer(
+ uint16_t, 0, 0, 0, __BYTE_ORDER, 10, none),
+ .u.sequence.elem_type = __type_integer(uint8_t, 0, 0, 0,
+ __BYTE_ORDER, 16, none),
+ ),
+ exceptfds,
+ ctf_custom_code(
+ unsigned int src;
+ unsigned int nr_bytes_out = 0;
+
+ if (exp) {
+ ctf_integer_type(uint16_t, tp_locvar->nr_bytes)
+ ctf_align(uint8_t)
+ } else {
+ ctf_integer_type(uint16_t, 0)
+ ctf_align(uint8_t)
+ goto skip_exp;
+ }
+
+ for (src = 0; src < tp_locvar->nr_ulong; src++) {
+ int dst;
+#if (__BYTE_ORDER == __LITTLE_ENDIAN)
+ for (dst = 0; dst < sizeof(long); dst++) {
+ ctf_user_integer_type(uint8_t,
+ ((uint8_t __user *) (exp->fds_bits + src))[dst]);
+ if (++nr_bytes_out >= tp_locvar->nr_bytes) {
+ goto skip_exp;
+ }
+ }
+#else
+ for (dst = sizeof(long); dst >= 0; dst--) {
+ ctf_user_integer_type(uint8_t,
+ ((uint8_t __user *) (exp->fds_bits + src))[dst]);
+ if (++nr_bytes_out >= tp_locvar->nr_bytes) {
+ goto skip_exp;
+ }
+ }
+#endif
+ }
+ skip_exp:
+ ;
+ )
+ )
+ )
+ ),
+ TP_code_post(
+ kfree(tp_locvar->fds_in);
+ kfree(tp_locvar->fds_out);
+ kfree(tp_locvar->fds_ex);
+ )
+)
+#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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