* filter.h (parse_filter_action, parse_filter_expression): Add new
declarations.
* filter_action.c (parse_filter_action): Add new parsing function.
* filter_expression.c (parse_filter_expression): Implement parsing of filter
expression.
(add_variable_token, add_operator_token, parse_operator, unescape_argument): Add
helper functions.
* filter_parse.c: New file.
* filter_qualify.c (parse_read, parse_write, qualify_signals, parse_trace,
parse_abbrev, parse_verbose, parse_raw, parse_inject_common, parse_fault,
parse_inject): Use new parsing api.
* strace.c (init): Use filtering_parse instead of parse_qualify_filter.
* Makefile.am (strace_SOURCES): Add filter_parse.c.
* defs.h (filtering_parse): Use common parsing function.
---
Makefile.am | 1 +
defs.h | 2 +-
filter.h | 4 +
filter_action.c | 9 +++
filter_expression.c | 229 ++++++++++++++++++++++++++++++++++++++++++++++++++++
filter_parse.c | 147 +++++++++++++++++++++++++++++++++
filter_qualify.c | 90 ++++++++++-----------
strace.c | 6 +-
8 files changed, 437 insertions(+), 51 deletions(-)
create mode 100644 filter_parse.c
diff --git a/Makefile.am b/Makefile.am
index ddc1fed..b2f11ca 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -134,6 +134,7 @@ strace_SOURCES = \
file_ioctl.c \
filter_action.c \
filter_expression.c \
+ filter_parse.c \
filter_qualify.c \
filter.c \
filter.h \
diff --git a/defs.h b/defs.h
index b03693d..c9876cc 100644
--- a/defs.h
+++ b/defs.h
@@ -684,7 +684,7 @@ extern struct number_set signal_set;
extern bool is_number_in_set(unsigned int number, const struct number_set *);
extern void filtering_parsing_finish(void);
extern void filter_syscall(struct tcb *);
-extern void parse_qualify_filter(const char *);
+extern void filtering_parse(const char *);
#define DECL_IOCTL(name) \
extern int \
diff --git a/filter.h b/filter.h
index 0017d6c..8b42208 100644
--- a/filter.h
+++ b/filter.h
@@ -57,6 +57,7 @@ void set_filters_qualify_mode(struct filter **, unsigned int
*nfilters);
/* filter action api */
struct filter *create_filter(struct filter_action *, const char *name);
struct filter_action *find_or_add_action(const char *);
+void parse_filter_action(const char *, const char *, const char *);
void *get_filter_action_priv_data(struct filter_action *);
void set_filter_action_priv_data(struct filter_action *, void *);
void set_qualify_mode(struct filter_action *);
@@ -65,5 +66,8 @@ void set_qualify_mode(struct filter_action *);
struct bool_expression *create_expression();
bool run_expression(struct bool_expression *, unsigned int, bool *);
void set_expression_qualify_mode(struct bool_expression *);
+void parse_filter_expression(struct bool_expression *, const char *,
+ struct filter_action *, unsigned int);
+void parse_qualify_action(const char *, const char *, const char *);
#endif
diff --git a/filter_action.c b/filter_action.c
index 4c944fc..a489436 100644
--- a/filter_action.c
+++ b/filter_action.c
@@ -185,6 +185,15 @@ find_or_add_action(const char *name)
return add_action(type);
}
+void
+parse_filter_action(const char *action_name, const char *expr,
+ const char *args)
+{
+ struct filter_action *action = find_or_add_action(action_name);
+ parse_filter_expression(action->expr, expr, action, action->nfilters);
+ action->_priv_data = action->type->parse_args(args);
+}
+
static void
run_filter_action(struct tcb *tcp, struct filter_action *action)
{
diff --git a/filter_expression.c b/filter_expression.c
index 8a41783..afb2642 100644
--- a/filter_expression.c
+++ b/filter_expression.c
@@ -25,6 +25,10 @@
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "defs.h"
+#include "filter.h"
+
+extern bool is_allowed_in_name(char);
+extern bool is_space_ascii(char);
struct expression_token {
enum token_type {
@@ -67,6 +71,34 @@ reallocate_expression(struct bool_expression *const expr,
expr->ntokens = new_ntokens;
}
+static void
+add_variable_token(struct bool_expression *expr, unsigned int id)
+{
+ struct expression_token token;
+ token.type = TOK_VARIABLE;
+ token.data.variable_id = id;
+ reallocate_expression(expr, expr->ntokens + 1);
+ expr->tokens[expr->ntokens - 1] = token;
+}
+
+static void
+add_operator_token(struct bool_expression *expr, char c) {
+ struct expression_token token;
+ token.type = TOK_OPERATOR;
+ switch (c){
+ case '!':
+ token.data.operator_id = OP_NOT;
+ break;
+ case '&':
+ token.data.operator_id = OP_AND;
+ break;
+ case '|':
+ token.data.operator_id = OP_OR;
+ }
+ reallocate_expression(expr, expr->ntokens + 1);
+ expr->tokens[expr->ntokens - 1] = token;
+}
+
#define STACK_SIZE 32
static bool stack[STACK_SIZE];
@@ -130,3 +162,200 @@ run_expression(struct bool_expression *expr,
error_msg_and_die("corrupted filter expression");
return stack[0];
}
+
+/* Parse operator and move str to the end of operator.
+ * Return \0 if no operator found.
+ */
+static char
+parse_operator(char **str)
+{
+ char *p = *str;
+ switch (*p) {
+ case '!':
+ return '!';
+ case '&':
+ if (p[1] == '&') {
+ *str = p + 1;
+ return '&';
+ }
+ break;
+ case '|':
+ if (p[1] == '|') {
+ *str = p + 1;
+ return '|';
+ }
+ break;
+ case 'n':
+ if (p[1] == 'o' && p[2] == 't' && !is_allowed_in_name(p[3])) {
+ *str = p + 2;
+ return '!';
+ }
+ break;
+ case 'a':
+ if (p[1] == 'n' && p[2] == 'd' && !is_allowed_in_name(p[3])) {
+ *str = p + 2;
+ return '&';
+ }
+ break;
+ case 'o':
+ if (p[1] == 'r' && !is_allowed_in_name(p[2])) {
+ *str = p + 1;
+ return '|';
+ }
+ }
+ return '\0';
+}
+
+static char *
+unescape_argument(char **str)
+{
+ char *p;
+ char *p_new;
+ bool escaped = false;
+ unsigned int size = 1;
+ char *new_str = xcalloc(strlen(*str) + 1, sizeof(char));
+ for (p = *str, p_new = new_str; *p; ++p) {
+ if (!escaped) {
+ if (*p == '\\') {
+ escaped = true;
+ continue;
+ } else if (is_space_ascii(*p) || *p == ')' || *p == '|'
+ || *p == '&') {
+ break;
+ }
+ }
+ escaped = false;
+ *(p_new++) = *p;
+ size++;
+ }
+ *str = p - 1;
+ xreallocarray(new_str, size, sizeof(char));
+ return new_str;
+}
+
+void
+parse_filter_expression(struct bool_expression *expr, const char *str,
+ struct filter_action *action, unsigned int start_id)
+{
+ enum {
+ WAIT_FILTER,
+ FILTER_NAME,
+ FILTER_ARG,
+ WAIT_OPERATOR
+ } state = WAIT_FILTER;
+ unsigned int variable_id = start_id;
+ /* Current stack index */
+ unsigned int index = 0;
+ char op_stack[STACK_SIZE];
+ char *buf = xstrdup(str);
+ struct filter *cur_filter = NULL;
+ char *filter_name = NULL;
+ char *filter_arg = NULL;
+ char *p;
+ for (p = buf; *p; ++p) {
+ switch (state) {
+ case WAIT_FILTER:
+ /* Ignore leading spaces */
+ if (is_space_ascii(*p))
+ continue;
+ switch (*p) {
+ case '(':
+ if (index == STACK_SIZE)
+ error_msg_and_die("stack overflow");
+ op_stack[index++] = '(';
+ continue;
+ /* Try to parse not operator. */
+ case '!':
+ case 'n':
+ {
+ char op = parse_operator(&p);
+ if (op == '!') {
+ if (index == STACK_SIZE)
+ error_msg_and_die("stack"
+ "overflow");
+ op_stack[index++] = '!';
+ continue;
+ } else if (op)
+ error_msg_and_die("invalid filter "
+ "expression '%s'", str);
+ }
+ default:
+ if (is_allowed_in_name(*p)) {
+ filter_name = p;
+ state = FILTER_NAME;
+ continue;
+ }
+ }
+ case FILTER_NAME:
+ if (is_allowed_in_name(*p)) {
+ continue;
+ } else if (is_space_ascii(*p)) {
+ *p = '\0';
+ cur_filter = create_filter(action, filter_name);
+ filter_arg = NULL;
+ state = FILTER_ARG;
+ continue;
+ } else {
+ error_msg_and_die("invalid filter "
+ "expression '%s'", str);
+ }
+ case FILTER_ARG:
+ if (!filter_arg && is_space_ascii(*p))
+ continue;
+ filter_arg = unescape_argument(&p);
+ error_msg("%s", filter_arg);
+ parse_filter(cur_filter, filter_arg);
+ free(filter_arg);
+ add_variable_token(expr, variable_id++);
+ state = WAIT_OPERATOR;
+ continue;
+ case WAIT_OPERATOR:
+ if (is_space_ascii(*p))
+ continue;
+ if (*p == ')') {
+ while ((index > 0)
+ && (op_stack[index - 1] != '('))
+ add_operator_token(expr,
+ op_stack[--index]);
+ if (index == 0)
+ error_msg_and_die("invalid filter "
+ "expression '%s'", str);
+ --index;
+ continue;
+ }
+ {
+ char op = parse_operator(&p);
+ if (!op || op == '!')
+ error_msg_and_die("invalid filter "
+ "expression '%s'", str);
+ /* Pop operators with higher priority. */
+ while ((index > 0)
+ && (op_stack[index - 1] == '!'))
+ add_operator_token(expr,
+ op_stack[--index]);
+ if (op == '|')
+ while ((index > 0)
+ && (op_stack[index - 1] == '&'))
+ add_operator_token(expr,
+ op_stack[--index]);
+ op_stack[index++] = op;
+ state = WAIT_FILTER;
+ continue;
+ }
+ }
+ }
+ free(buf);
+ while (index > 0)
+ add_operator_token(expr, op_stack[--index]);
+ if (start_id > 0)
+ add_operator_token(expr, '&');
+ struct expression_token *tok = expr->tokens;
+ struct expression_token *const tok_end = expr->tokens + expr->ntokens;
+ for (; tok != tok_end; ++tok) {
+ if (tok->type == TOK_VARIABLE) {
+ error_msg("variable: %u", tok->data.variable_id);
+ } else {
+ error_msg("operator: %u", tok->data.operator_id);
+ }
+ }
+}
diff --git a/filter_parse.c b/filter_parse.c
new file mode 100644
index 0000000..93a37d8
--- /dev/null
+++ b/filter_parse.c
@@ -0,0 +1,147 @@
+/*
+ * Copyright (c) 2017 Nikolay Marchuk <marchuk.nikola...@gmail.com>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ * derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+#include "defs.h"
+#include "filter.h"
+
+bool
+is_allowed_in_name(char c)
+{
+ return (c >= 'A' && c <= 'Z') || (c >= 'a' && c <= 'z')
+ || (c >= '0' && c <= '9') || (c == '_');
+}
+
+bool
+is_space_ascii(char c)
+{
+ return (c == ' ') || (c == '\t') || (c == '\n') || (c == '\r') ||
+ (c == '\v') || (c == '\f');
+}
+
+void
+filtering_parse(const char *str)
+{
+ enum parsing_states {
+ F_BEGIN,
+ F_QUAL_SET,
+ F_FILT_EXPR,
+ F_QUAL_ARGS,
+ F_FILT_ARGS
+ } state = F_BEGIN;
+ const char *action_name = NULL;
+ const char *main_part = NULL;
+ const char *args = NULL;
+ unsigned int str_len = strlen(str);
+ char *buf = xstrdup(str);
+ char *p;
+ for (p = buf; *p; ++p) {
+ switch (state) {
+ case F_BEGIN:
+ switch (*p) {
+ /* action(...) */
+ case '(':
+ if (p != buf) {
+ if (buf[str_len - 1] != ')')
+ error_msg_and_die("missing ')'"
+ " in '%s'", str);
+ *p = '\0';
+ buf[str_len - 1] = '\0';
+ action_name = buf;
+ main_part = p + 1;
+ state = F_FILT_EXPR;
+ } else {
+ action_name = "trace";
+ main_part = buf;
+ state = F_FILT_EXPR;
+ }
+ continue;
+ /* action=... */
+ case '=':
+ if (p == buf) {
+ error_msg_and_die("invalid expression "
+ "'%s'", str);
+ }
+ *p = '\0';
+ action_name = buf;
+ main_part = p + 1;
+ state = F_QUAL_SET;
+ continue;
+ /* qualify set without action. */
+ case ',':
+ case '?':
+ case '!':
+ case '/':
+ case '%':
+ case '-':
+ action_name = "trace";
+ main_part = buf;
+ state = F_QUAL_SET;
+ continue;
+ default:
+ /* new expression without action. */
+ if (is_space_ascii(*p)) {
+ action_name = "trace";
+ main_part = buf;
+ state = F_FILT_EXPR;
+ continue;
+ }
+ if (!is_allowed_in_name(*p))
+ error_msg_and_die("invalid expression "
+ "'%s'", str);
+ }
+ case F_QUAL_SET:
+ if (*p == ':') {
+ *p = '\0';
+ args = p + 1;
+ state = F_QUAL_ARGS;
+ continue;
+ }
+ case F_FILT_EXPR:
+ if (*p == ';') {
+ *p = '\0';
+ args = p + 1;
+ state = F_FILT_ARGS;
+ continue;
+ }
+ case F_QUAL_ARGS:
+ case F_FILT_ARGS:
+ continue;
+ }
+ }
+ switch (state) {
+ case F_BEGIN:
+ action_name = "trace";
+ main_part = buf;
+ case F_QUAL_SET:
+ case F_QUAL_ARGS:
+ parse_qualify_action(action_name, main_part, args);
+ break;
+ case F_FILT_EXPR:
+ case F_FILT_ARGS:
+ parse_filter_action(action_name, main_part, args);
+ break;
+ }
+}
diff --git a/filter_qualify.c b/filter_qualify.c
index 7d65963..c3a476d 100644
--- a/filter_qualify.c
+++ b/filter_qualify.c
@@ -178,86 +178,87 @@ parse_inject_common_args(char *str, struct inject_opts
*const opts,
}
static void
-parse_read(const char *const str)
+parse_read(const char *const main_part, const char *const args)
{
struct filter_action *action = find_or_add_action("read");
struct filter *filter = create_filter(action, "fd");
- parse_filter(filter, str);
+ parse_filter(filter, main_part);
set_qualify_mode(action);
}
static void
-parse_write(const char *const str)
+parse_write(const char *const main_part, const char *const args)
{
struct filter_action *action = find_or_add_action("write");
struct filter *filter = create_filter(action, "fd");
- parse_filter(filter, str);
+ parse_filter(filter, main_part);
set_qualify_mode(action);
}
static void
-qualify_signals(const char *const str)
+qualify_signals(const char *const main_part, const char *const args)
{
- parse_set(str, &signal_set, sigstr_to_uint, "signal");
+ parse_set(main_part, &signal_set, sigstr_to_uint, "signal");
}
static void
-parse_trace(const char *const str)
+parse_trace(const char *const main_part, const char *const args)
{
+ if (args && *args)
+ error_msg_and_die("invalid filter action arguments '%s'", args);
struct filter_action *action = find_or_add_action("trace");
struct filter *filter = create_filter(action, "syscall");
- parse_filter(filter, str);
+ parse_filter(filter, main_part);
set_qualify_mode(action);
}
static void
-parse_abbrev(const char *const str)
+parse_abbrev(const char *const main_part, const char *const args)
{
+ if (args && *args)
+ error_msg_and_die("invalid filter action arguments '%s'", args);
struct filter_action *action = find_or_add_action("abbrev");
struct filter *filter = create_filter(action, "syscall");
- parse_filter(filter, str);
+ parse_filter(filter, main_part);
set_qualify_mode(action);
}
static void
-parse_verbose(const char *const str)
+parse_verbose(const char *const main_part, const char *const args)
{
+ if (args && *args)
+ error_msg_and_die("invalid filter action arguments '%s'", args);
struct filter_action *action = find_or_add_action("verbose");
struct filter *filter = create_filter(action, "syscall");
- parse_filter(filter, str);
+ parse_filter(filter, main_part);
set_qualify_mode(action);
}
static void
-parse_raw(const char *const str)
+parse_raw(const char *const main_part, const char *const args)
{
+ if (args && *args)
+ error_msg_and_die("invalid filter action arguments '%s'", args);
struct filter_action *action = find_or_add_action("raw");
struct filter *filter = create_filter(action, "syscall");
- parse_filter(filter, str);
+ parse_filter(filter, main_part);
set_qualify_mode(action);
}
static void
-parse_inject_common(const char *const str,
- const bool fault_tokens_only,
- const char *const description)
+parse_inject_common(const char *const main_part, const char *const args,
+ const bool fault_tokens_only,
+ const char *const description)
{
struct inject_opts *opts = xmalloc(sizeof(struct inject_opts));
- char *buf = xstrdup(str);
- char *name = buf;
- char *args = strchr(buf, ':');
- if (!args) {
- args = NULL;
- } else {
- *(args++) = '\0';
- }
+ char *buf = args ? xstrdup(args) : NULL;
struct filter_action *action = find_or_add_action("inject");
struct filter *filter = create_filter(action, "syscall");
- parse_filter(filter, name);
+ parse_filter(filter, main_part);
set_qualify_mode(action);
- parse_inject_common_args(args, opts, ":", fault_tokens_only);
+ parse_inject_common_args(buf, opts, ":", fault_tokens_only);
if (!opts->init) {
error_msg_and_die("invalid %s '%s'", description, args);
}
@@ -266,20 +267,20 @@ parse_inject_common(const char *const str,
}
static void
-parse_fault(const char *const str)
+parse_fault(const char *const main_part, const char *const args)
{
- parse_inject_common(str, true, "fault argument");
+ parse_inject_common(main_part, args, true, "fault argument");
}
static void
-parse_inject(const char *const str)
+parse_inject(const char *const main_part, const char *const args)
{
- parse_inject_common(str, false, "inject argument");
+ parse_inject_common(main_part, args, false, "inject argument");
}
static const struct qual_options {
const char *name;
- void (*qualify)(const char *);
+ void (*qualify)(const char *, const char *);
} qual_options[] = {
{ "trace", parse_trace },
{ "t", parse_trace },
@@ -302,23 +303,18 @@ static const struct qual_options {
{ "inject", parse_inject },
};
-void
-parse_qualify_filter(const char *str)
+void parse_qualify_action(const char *action_name, const char *main_part,
+ const char *args)
{
- const struct qual_options *opt = qual_options;
+ const struct qual_options *opt = NULL;
unsigned int i;
-
for (i = 0; i < ARRAY_SIZE(qual_options); ++i) {
- const char *name = qual_options[i].name;
- const size_t len = strlen(name);
- const char *val = str_strip_prefix_len(str, name, len);
-
- if (val == str || *val != '=')
- continue;
- str = val + 1;
- opt = &qual_options[i];
- break;
+ if (!strcmp(action_name, qual_options[i].name)) {
+ opt = &qual_options[i];
+ break;
+ }
}
-
- opt->qualify(str);
+ if (!opt)
+ error_msg_and_die("invalid filter action '%s'", action_name);
+ opt->qualify(main_part, args);
}
diff --git a/strace.c b/strace.c
index b8c027a..6f8022a 100644
--- a/strace.c
+++ b/strace.c
@@ -1640,7 +1640,7 @@ init(int argc, char *argv[])
#if DEFAULT_QUAL_FLAGS != (QUAL_TRACE | QUAL_ABBREV | QUAL_VERBOSE)
# error Bug in DEFAULT_QUAL_FLAGS
#endif
- parse_qualify_filter("signal=all");
+ filtering_parse("signal=all");
while ((c = getopt(argc, argv,
"+b:cCdfFhiqrtTvVwxyz"
#ifdef USE_LIBUNWIND
@@ -1707,7 +1707,7 @@ init(int argc, char *argv[])
show_fd_path++;
break;
case 'v':
- parse_qualify_filter("abbrev=none");
+ filtering_parse("abbrev=none");
break;
case 'V':
print_version();
@@ -1722,7 +1722,7 @@ init(int argc, char *argv[])
error_opt_arg(c, optarg);
break;
case 'e':
- parse_qualify_filter(optarg);
+ filtering_parse(optarg);
break;
case 'o':
outfname = xstrdup(optarg);
--
2.1.4
------------------------------------------------------------------------------
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