[lttng-dev] [PATCH lttng-modules v4 2/5] Extract the FD sets in select and pselect6
Mathieu Desnoyers
mathieu.desnoyers at efficios.com
Fri Apr 15 21:32:00 UTC 2016
----- On Apr 15, 2016, at 4:37 PM, Julien Desfossez jdesfossez at efficios.com wrote:
> 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 | 287 +++++++++++++++++++++
> 1 file changed, 287 insertions(+)
>
> diff --git a/instrumentation/syscalls/headers/syscalls_pointers_override.h
> b/instrumentation/syscalls/headers/syscalls_pointers_override.h
> index bf5c632..debd4b2 100644
> --- a/instrumentation/syscalls/headers/syscalls_pointers_override.h
> +++ b/instrumentation/syscalls/headers/syscalls_pointers_override.h
> @@ -53,4 +53,291 @@ 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(
> + uint8_t *fds_in, *fds_out, *fds_ex;
> + int nb_in, nb_out, nb_ex;
> + ),
> + TP_code_pre(
> + sc_in(
> + {
> + unsigned long nr_bytes;
> + int err;
> +
> + tp_locvar->fds_in = NULL;
> + tp_locvar->fds_out = NULL;
> + tp_locvar->fds_ex = NULL;
> +
> + tp_locvar->nb_in = 0;
> + tp_locvar->nb_out = 0;
> + tp_locvar->nb_ex = 0;
> +
> + if (n <= 0) {
> + nr_bytes = 0;
> + } else {
> + nr_bytes = DIV_ROUND_UP((unsigned int) n, BITS_PER_BYTE);
> + /* On error or bogus input, don't copy anything. */
> + if (nr_bytes > (__FD_SETSIZE / (8 * sizeof(uint8_t)))) {
> + nr_bytes = 0;
> + }
> + }
> + if (inp) {
> + tp_locvar->fds_in = kmalloc((__FD_SETSIZE / (8 * sizeof(uint8_t))) *
> + sizeof(uint8_t), GFP_KERNEL);
> + if (!tp_locvar->fds_in)
> + goto skip_code;
> +
> + err = copy_from_user(tp_locvar->fds_in, inp, nr_bytes);
> + if (err < 0)
> + goto skip_code;
> + tp_locvar->nb_in = nr_bytes;
> + }
> + if (outp) {
> + tp_locvar->fds_out = kmalloc((__FD_SETSIZE / (8 * sizeof(uint8_t))) *
> + sizeof(uint8_t), GFP_KERNEL);
> + if (!tp_locvar->fds_out)
> + goto skip_code;
> +
> + err = copy_from_user(tp_locvar->fds_out, outp, nr_bytes);
> + if (err < 0)
> + goto skip_code;
> + tp_locvar->nb_out = nr_bytes;
> + }
> + if (exp) {
> + tp_locvar->fds_ex = kmalloc((__FD_SETSIZE / (8 * sizeof(uint8_t))) *
> + sizeof(uint8_t), GFP_KERNEL);
> + if (!tp_locvar->fds_ex)
> + goto skip_code;
> +
> + err = copy_from_user(tp_locvar->fds_ex, exp, nr_bytes);
> + if (err < 0)
> + goto skip_code;
> + tp_locvar->nb_ex = nr_bytes;
> + }
> + }
> + skip_code:
> + )
> + sc_out(
> + {
> + unsigned long nr_bytes;
> + int err;
> +
> + tp_locvar->fds_in = NULL;
> + tp_locvar->fds_out = NULL;
> + tp_locvar->fds_ex = NULL;
You forgot to allocate those in the sc_out. The are only
allocated in the sc_in (entry to syscall), not sc_out().
Mathieu
> +
> + tp_locvar->nb_in = 0;
> + tp_locvar->nb_out = 0;
> + tp_locvar->nb_ex = 0;
> +
> + if (ret <= 0)
> + goto skip_code;
> +
> + if (n <= 0) {
> + nr_bytes = 0;
> + } else {
> + nr_bytes = DIV_ROUND_UP((unsigned int) n, BITS_PER_BYTE);
> + /* On error or bogus input, don't copy anything. */
> + if (nr_bytes > (__FD_SETSIZE / (8 * sizeof(uint8_t)))) {
> + nr_bytes = 0;
> + }
> + }
> + if (inp && tp_locvar->fds_in) {
> + err = copy_from_user(tp_locvar->fds_in, inp, nr_bytes);
> + if (err < 0)
> + goto skip_code;
> + tp_locvar->nb_in = nr_bytes;
> + }
> + if (outp && tp_locvar->fds_out) {
> + err = copy_from_user(tp_locvar->fds_out, outp, nr_bytes);
> + if (err < 0)
> + goto skip_code;
> + tp_locvar->nb_out = nr_bytes;
> + }
> + if (exp && tp_locvar->fds_ex) {
> + err = copy_from_user(tp_locvar->fds_ex, exp, nr_bytes);
> + if (err < 0)
> + goto skip_code;
> + tp_locvar->nb_ex = nr_bytes;
> + }
> + }
> + skip_code:
> + )
> + ),
> + TP_FIELDS(
> + sc_exit(ctf_integer(long, ret, ret))
> + sc_in(ctf_integer(int, n, n))
> + sc_inout(ctf_sequence_hex(uint8_t, fdset_in,
> + tp_locvar->fds_in, uint8_t, tp_locvar->nb_in))
> + sc_inout(ctf_sequence_hex(uint8_t, fdset_out,
> + tp_locvar->fds_out, uint8_t, tp_locvar->nb_out))
> + sc_inout(ctf_sequence_hex(uint8_t, fdset_ex,
> + tp_locvar->fds_ex, uint8_t, tp_locvar->nb_ex))
> + sc_inout(ctf_integer(struct timeval *, tvp, tvp))
> + ),
> + 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(
> + uint8_t *fds_in, *fds_out, *fds_ex;
> + int nb_in, nb_out, nb_ex;
> + ),
> + TP_code_pre(
> + sc_in(
> + {
> + unsigned long nr_bytes;
> + int err;
> +
> + tp_locvar->fds_in = NULL;
> + tp_locvar->fds_out = NULL;
> + tp_locvar->fds_ex = NULL;
> +
> + tp_locvar->nb_in = 0;
> + tp_locvar->nb_out = 0;
> + tp_locvar->nb_ex = 0;
> +
> + if (n <= 0) {
> + nr_bytes = 0;
> + } else {
> + nr_bytes = DIV_ROUND_UP((unsigned int) n, BITS_PER_BYTE);
> + /* On error or bogus input, don't copy anything. */
> + if (nr_bytes > (__FD_SETSIZE / (8 * sizeof(uint8_t)))) {
> + nr_bytes = 0;
> + }
> + }
> + if (inp) {
> + tp_locvar->fds_in = kmalloc((__FD_SETSIZE / (8 * sizeof(uint8_t))) *
> + sizeof(uint8_t), GFP_KERNEL);
> + if (!tp_locvar->fds_in)
> + goto skip_code;
> +
> + err = copy_from_user(tp_locvar->fds_in, inp, nr_bytes);
> + if (err < 0)
> + goto skip_code;
> + tp_locvar->nb_in = nr_bytes;
> + }
> + if (outp) {
> + tp_locvar->fds_out = kmalloc((__FD_SETSIZE / (8 * sizeof(uint8_t))) *
> + sizeof(uint8_t), GFP_KERNEL);
> + if (!tp_locvar->fds_out)
> + goto skip_code;
> +
> + err = copy_from_user(tp_locvar->fds_out, outp, nr_bytes);
> + if (err < 0)
> + goto skip_code;
> + tp_locvar->nb_out = nr_bytes;
> + }
> + if (exp) {
> + tp_locvar->fds_ex = kmalloc((__FD_SETSIZE / (8 * sizeof(uint8_t))) *
> + sizeof(uint8_t), GFP_KERNEL);
> + if (!tp_locvar->fds_ex)
> + goto skip_code;
> +
> + err = copy_from_user(tp_locvar->fds_ex, exp, nr_bytes);
> + if (err < 0)
> + goto skip_code;
> + tp_locvar->nb_ex = nr_bytes;
> + }
> + }
> + skip_code:
> + )
> + sc_out(
> + {
> + unsigned long nr_bytes;
> + int err;
> +
> + tp_locvar->fds_in = NULL;
> + tp_locvar->fds_out = NULL;
> + tp_locvar->fds_ex = NULL;
> +
> + tp_locvar->nb_in = 0;
> + tp_locvar->nb_out = 0;
> + tp_locvar->nb_ex = 0;
> +
> + if (ret <= 0)
> + goto skip_code;
> +
> + if (n <= 0) {
> + nr_bytes = 0;
> + } else {
> + nr_bytes = DIV_ROUND_UP((unsigned int) n, BITS_PER_BYTE);
> + /* On error or bogus input, don't copy anything. */
> + if (nr_bytes > (__FD_SETSIZE / (8 * sizeof(uint8_t)))) {
> + nr_bytes = 0;
> + }
> + }
> + if (inp) {
> + tp_locvar->fds_in = kmalloc((__FD_SETSIZE / (8 * sizeof(uint8_t))) *
> + sizeof(uint8_t), GFP_KERNEL);
> + if (!tp_locvar->fds_in)
> + goto skip_code;
> +
> + err = copy_from_user(tp_locvar->fds_in, inp, nr_bytes);
> + if (err < 0)
> + goto skip_code;
> + tp_locvar->nb_in = nr_bytes;
> + }
> + if (outp) {
> + tp_locvar->fds_out = kmalloc((__FD_SETSIZE / (8 * sizeof(uint8_t))) *
> + sizeof(uint8_t), GFP_KERNEL);
> + if (!tp_locvar->fds_out)
> + goto skip_code;
> +
> + err = copy_from_user(tp_locvar->fds_out, outp, nr_bytes);
> + if (err < 0)
> + goto skip_code;
> + tp_locvar->nb_out = nr_bytes;
> + }
> + if (exp) {
> + tp_locvar->fds_ex = kmalloc((__FD_SETSIZE / (8 * sizeof(uint8_t))) *
> + sizeof(uint8_t), GFP_KERNEL);
> + if (!tp_locvar->fds_ex)
> + goto skip_code;
> +
> + err = copy_from_user(tp_locvar->fds_ex, exp, nr_bytes);
> + if (err < 0)
> + goto skip_code;
> + tp_locvar->nb_ex = nr_bytes;
> + }
> + }
> + skip_code:
> + )
> + ),
> + TP_FIELDS(
> + sc_exit(ctf_integer(long, ret, ret))
> + sc_in(ctf_integer(int, n, n))
> + sc_inout(ctf_sequence_hex(uint8_t, fdset_in,
> + tp_locvar->fds_in, uint8_t, tp_locvar->nb_in))
> + sc_inout(ctf_sequence_hex(uint8_t, fdset_out,
> + tp_locvar->fds_out, uint8_t, tp_locvar->nb_out))
> + sc_inout(ctf_sequence_hex(uint8_t, fdset_ex,
> + tp_locvar->fds_ex, uint8_t, tp_locvar->nb_ex))
> + sc_inout(ctf_integer(struct timeval *, tvp, tvp))
> + ),
> + 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
--
Mathieu Desnoyers
EfficiOS Inc.
http://www.efficios.com
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