On Tue, Apr 11, 2017 at 08:27:12AM +0800, JingPiao Chen wrote: > * qualify.c (qualify_syscall_regex): New function. > (qualify_syscall_name): Use qualify_syscall_regex function. > * tests/regex.test: Check this. > * tests/Makefile.am (DECODER_TESTS): Add regex.test.
Great. It definitely requires a piece of documentation in strace.1
and a NEWS entry.
> ---
> qualify.c | 36 +++++++++++++++++++++++++++
> tests/Makefile.am | 1 +
> tests/regex.test | 74
> +++++++++++++++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 111 insertions(+)
> create mode 100755 tests/regex.test
>
> diff --git a/qualify.c b/qualify.c
> index 157d313..783bb4a 100644
> --- a/qualify.c
> +++ b/qualify.c
> @@ -27,6 +27,7 @@
>
> #include "defs.h"
> #include "nsig.h"
> +#include <regex.h>
>
> typedef unsigned int number_slot_t;
> #define BITS_PER_SLOT (sizeof(number_slot_t) * 8)
> @@ -258,6 +259,40 @@ qualify_syscall_class(const char *s, struct number_set
> *set)
> }
>
> static bool
> +qualify_syscall_regex(const char *s, struct number_set *set)
> +{
> + int len = strlen(s);
> +
> + if(!s || s[0] != '/' || s[len - 1] != '/')
> + return false;
> +
> + char *copy = xstrdup(s);
> + copy[len - 1] = '\0';
I do think that trace=/REGEX/ has some unhealthy redundancy.
The leading slash is enough. Let it be trace=/REGEX instead.
It would simplify the code, too.
> + regex_t preg;
> + if (regcomp(&preg, copy + 1, REG_EXTENDED | REG_NOSUB))
> + error_msg_and_die("invalid regular expression: '%s'", copy + 1);
Please use regerror() to make error diagnostics more descriptive.
> + free(copy);
> +
> + unsigned int p;
> + for (p = 0; p < SUPPORTED_PERSONALITIES; ++p) {
> + unsigned int i;
> +
> + for (i = 0; i < nsyscall_vec[p]; ++i) {
> + if (!sysent_vec[p][i].sys_name
> + || regexec(&preg, sysent_vec[p][i].sys_name,
> + 0, NULL, 0)) {
> + continue;
regexec can return values other than zero or REG_NOMATCH, they are errors
that have to be handled.
> + }
> + add_number_to_set(i, &set[p]);
> + }
> + }
> +
> + regfree(&preg);
> + return true;
> +}
qualify_syscall_regex should have the same "return found" semantics as
qualify_syscall_name, so a regular expression that matches no syscalls
would be a syntax error.
> +static bool
> qualify_syscall_name(const char *s, struct number_set *set)
> {
> unsigned int p;
> @@ -285,6 +320,7 @@ qualify_syscall(const char *token, struct number_set *set)
> if (*token >= '0' && *token <= '9')
> return qualify_syscall_number(token, set);
> return qualify_syscall_class(token, set)
> + || qualify_syscall_regex(token, set)
> || qualify_syscall_name(token, set);
As there are no class or syscall name that start with a slash,
I think it should be
if (*token == '/')
return qualify_syscall_regex(token, set);
[...]
> --- /dev/null
> +++ b/tests/regex.test
> @@ -0,0 +1,74 @@
> +#!/bin/sh
> +#
> +# Check -e trace=/REGEX/ option.
Please also add a check for an invalid regexp and a regexp that would
never match a syscall.
--
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