@@ -39,10 +39,13 @@ along with GCC; see the file COPYING3. If not see
#include "analyzer/analyzer-selftests.h"
#include "tristate.h"
#include "selftest.h"
+#include "stringpool.h"
+#include "attribs.h"
#include "analyzer/call-string.h"
#include "analyzer/program-point.h"
#include "analyzer/store.h"
#include "analyzer/region-model.h"
+#include "bitmap.h"
#if ENABLE_ANALYZER
@@ -59,6 +62,13 @@ enum access_mode
WRITE_ONLY
};
+enum access_directions
+{
+ DIRS_READ_WRITE,
+ DIRS_READ,
+ DIRS_WRITE
+};
+
class fd_state_machine : public state_machine
{
public:
@@ -146,7 +156,7 @@ private:
void check_for_open_fd (sm_context *sm_ctxt, const supernode *node,
const gimple *stmt, const gcall *call,
const tree callee_fndecl,
- enum access_direction access_fn) const;
+ enum access_directions access_fn) const;
void make_valid_transitions_on_condition (sm_context *sm_ctxt,
const supernode *node,
@@ -156,12 +166,17 @@ private:
const supernode *node,
const gimple *stmt,
const svalue *lhs) const;
+ void check_for_fd_attrs (sm_context *sm_ctxt, const supernode *node,
+ const gimple *stmt, const tree callee_fndecl,
+ const char *attr_name,
+ access_directions fd_attr_access_dir) const;
+
};
/* Base diagnostic class relative to fd_state_machine. */
class fd_diagnostic : public pending_diagnostic
{
-public:
+public:
fd_diagnostic (const fd_state_machine &sm, tree arg) : m_sm (sm), m_arg (arg)
{
}
@@ -220,6 +235,65 @@ protected:
tree m_arg;
};
+class fd_param_diagnostic : public fd_diagnostic
+{
+public:
+ fd_param_diagnostic (const fd_state_machine &sm, tree arg, tree callee_fndecl,
+ bool attr, int arg_idx)
+ : fd_diagnostic (sm, arg), m_callee_fndecl (callee_fndecl), m_attr (attr),
+ m_arg_idx (arg_idx)
+ {
+ }
+
+ fd_param_diagnostic (const fd_state_machine &sm, tree arg, tree callee_fndecl)
+ : fd_diagnostic (sm, arg), m_callee_fndecl (callee_fndecl),
+ m_attr (false), m_arg_idx (-1)
+ {
+ }
+
+ bool
+ subclass_equal_p (const pending_diagnostic &base_other) const override
+ {
+ const fd_param_diagnostic &sub_other
+ = (const fd_param_diagnostic &)base_other;
+ return (same_tree_p (m_arg, sub_other.m_arg)
+ && m_callee_fndecl == sub_other.m_callee_fndecl
+ && m_attr == sub_other.m_attr
+ && m_arg_idx == sub_other.m_arg_idx);
+ }
+
+ void
+ inform_filedescriptor_attribute (access_directions fd_dir)
+ {
+
+ if (m_attr)
+ switch (fd_dir)
+ {
+ case DIRS_READ_WRITE:
+ inform (DECL_SOURCE_LOCATION (m_callee_fndecl),
+ "argument %d of %qD must be an open file descriptor",
+ m_arg_idx + 1, m_callee_fndecl);
+ break;
+ case DIRS_WRITE:
+ inform (DECL_SOURCE_LOCATION (m_callee_fndecl),
+ "argument %d of %qD must be a read-only file descriptor",
+ m_arg_idx + 1, m_callee_fndecl);
+ break;
+ case DIRS_READ:
+ inform (DECL_SOURCE_LOCATION (m_callee_fndecl),
+ "argument %d of %qD must be a write-only file descriptor",
+ m_arg_idx + 1, m_callee_fndecl);
+ break;
+ }
+ }
+
+protected:
+ tree m_callee_fndecl;
+ bool m_attr;
+ /* ARG_IDX is 0-based. */
+ int m_arg_idx;
+};
+
class fd_leak : public fd_diagnostic
{
public:
@@ -290,18 +364,25 @@ private:
diagnostic_event_id_t m_open_event;
};
-class fd_access_mode_mismatch : public fd_diagnostic
+class fd_access_mode_mismatch : public fd_param_diagnostic
{
public:
fd_access_mode_mismatch (const fd_state_machine &sm, tree arg,
- enum access_direction fd_dir,
- const tree callee_fndecl)
- : fd_diagnostic (sm, arg), m_fd_dir (fd_dir),
- m_callee_fndecl (callee_fndecl)
+ enum access_directions fd_dir,
+ const tree callee_fndecl, bool attr, int arg_idx)
+ : fd_param_diagnostic (sm, arg, callee_fndecl, attr, arg_idx),
+ m_fd_dir (fd_dir)
{
}
+ fd_access_mode_mismatch (const fd_state_machine &sm, tree arg,
+ enum access_directions fd_dir,
+ const tree callee_fndecl)
+ : fd_param_diagnostic (sm, arg, callee_fndecl), m_fd_dir (fd_dir)
+ {
+ }
+
const char *
get_kind () const final override
{
@@ -317,29 +398,25 @@ public:
bool
emit (rich_location *rich_loc) final override
{
+ bool warned;
switch (m_fd_dir)
{
- case DIR_READ:
- return warning_at (rich_loc, get_controlling_option (),
+ case DIRS_READ:
+ warned = warning_at (rich_loc, get_controlling_option (),
"%qE on %<read-only%> file descriptor %qE",
m_callee_fndecl, m_arg);
- case DIR_WRITE:
- return warning_at (rich_loc, get_controlling_option (),
+ break;
+ case DIRS_WRITE:
+ warned = warning_at (rich_loc, get_controlling_option (),
"%qE on %<write-only%> file descriptor %qE",
m_callee_fndecl, m_arg);
+ break;
default:
gcc_unreachable ();
}
- }
-
- bool
- subclass_equal_p (const pending_diagnostic &base_other) const override
- {
- const fd_access_mode_mismatch &sub_other
- = (const fd_access_mode_mismatch &)base_other;
- return (same_tree_p (m_arg, sub_other.m_arg)
- && m_callee_fndecl == sub_other.m_callee_fndecl
- && m_fd_dir == sub_other.m_fd_dir);
+ if (warned)
+ inform_filedescriptor_attribute (m_fd_dir);
+ return warned;
}
label_text
@@ -347,10 +424,10 @@ public:
{
switch (m_fd_dir)
{
- case DIR_READ:
+ case DIRS_READ:
return ev.formatted_print ("%qE on %<read-only%> file descriptor %qE",
m_callee_fndecl, m_arg);
- case DIR_WRITE:
+ case DIRS_WRITE:
return ev.formatted_print ("%qE on %<write-only%> file descriptor %qE",
m_callee_fndecl, m_arg);
default:
@@ -359,21 +436,20 @@ public:
}
private:
- enum access_direction m_fd_dir;
- const tree m_callee_fndecl;
+ enum access_directions m_fd_dir;
};
-class double_close : public fd_diagnostic
+class fd_double_close : public fd_diagnostic
{
public:
- double_close (const fd_state_machine &sm, tree arg) : fd_diagnostic (sm, arg)
+ fd_double_close (const fd_state_machine &sm, tree arg) : fd_diagnostic (sm, arg)
{
}
const char *
get_kind () const final override
{
- return "double_close";
+ return "fd_double_close";
}
int
@@ -418,12 +494,18 @@ private:
diagnostic_event_id_t m_first_close_event;
};
-class fd_use_after_close : public fd_diagnostic
+class fd_use_after_close : public fd_param_diagnostic
{
public:
+ fd_use_after_close (const fd_state_machine &sm, tree arg,
+ const tree callee_fndecl, bool attr, int arg_idx)
+ : fd_param_diagnostic(sm, arg, callee_fndecl, attr, arg_idx)
+ {
+ }
+
fd_use_after_close (const fd_state_machine &sm, tree arg,
const tree callee_fndecl)
- : fd_diagnostic (sm, arg), m_callee_fndecl (callee_fndecl)
+ : fd_param_diagnostic(sm, arg, callee_fndecl)
{
}
@@ -442,9 +524,13 @@ public:
bool
emit (rich_location *rich_loc) final override
{
- return warning_at (rich_loc, get_controlling_option (),
+ bool warned;
+ warned = warning_at (rich_loc, get_controlling_option (),
"%qE on closed file descriptor %qE", m_callee_fndecl,
m_arg);
+ if (warned)
+ inform_filedescriptor_attribute (DIRS_READ_WRITE);
+ return warned;
}
label_text
@@ -466,32 +552,37 @@ public:
describe_final_event (const evdesc::final_event &ev) final override
{
if (m_first_close_event.known_p ())
- return ev.formatted_print (
- "%qE on closed file descriptor %qE; %qs was at %@", m_callee_fndecl,
- m_arg, "close", &m_first_close_event);
- else
- return ev.formatted_print ("%qE on closed file descriptor %qE",
- m_callee_fndecl, m_arg);
+ return ev.formatted_print (
+ "%qE on closed file descriptor %qE; %qs was at %@", m_callee_fndecl,
+ m_arg, "close", &m_first_close_event);
+ else
+ return ev.formatted_print ("%qE on closed file descriptor %qE",
+ m_callee_fndecl, m_arg);
}
private:
diagnostic_event_id_t m_first_close_event;
- const tree m_callee_fndecl;
};
-class unchecked_use_of_fd : public fd_diagnostic
+class fd_use_without_check : public fd_param_diagnostic
{
public:
- unchecked_use_of_fd (const fd_state_machine &sm, tree arg,
+ fd_use_without_check (const fd_state_machine &sm, tree arg,
+ const tree callee_fndecl, bool attr, int arg_idx)
+ : fd_param_diagnostic(sm, arg, callee_fndecl, attr, arg_idx)
+ {
+ }
+
+ fd_use_without_check (const fd_state_machine &sm, tree arg,
const tree callee_fndecl)
- : fd_diagnostic (sm, arg), m_callee_fndecl (callee_fndecl)
+ : fd_param_diagnostic(sm, arg, callee_fndecl)
{
}
const char *
get_kind () const final override
{
- return "unchecked_use_of_fd";
+ return "fd_use_without_check";
}
int
@@ -503,18 +594,12 @@ public:
bool
emit (rich_location *rich_loc) final override
{
- return warning_at (rich_loc, get_controlling_option (),
- "%qE on possibly invalid file descriptor %qE",
- m_callee_fndecl, m_arg);
- }
-
- bool
- subclass_equal_p (const pending_diagnostic &base_other) const override
- {
- const unchecked_use_of_fd &sub_other
- = (const unchecked_use_of_fd &)base_other;
- return (same_tree_p (m_arg, sub_other.m_arg)
- && m_callee_fndecl == sub_other.m_callee_fndecl);
+ bool warned;
+ warned = warning_at (rich_loc, get_controlling_option (),
+ "%qE on possibly invalid file descriptor %qE",
+ m_callee_fndecl, m_arg);
+ if (warned)
+ inform_filedescriptor_attribute (DIRS_READ_WRITE);
}
label_text
@@ -542,7 +627,7 @@ public:
private:
diagnostic_event_id_t m_first_open_event;
- const tree m_callee_fndecl;
+
};
fd_state_machine::fd_state_machine (logger *logger)
@@ -647,11 +732,119 @@ fd_state_machine::on_stmt (sm_context *sm_ctxt, const supernode *node,
on_read (sm_ctxt, node, stmt, call, callee_fndecl);
return true;
} // "read"
+
+
+ {
+ // Handle __attribute__((fd_arg))
+
+ check_for_fd_attrs (sm_ctxt, node, stmt, callee_fndecl, "fd_arg", DIRS_READ_WRITE);
+
+ // Handle __attribute__((fd_arg_read))
+
+ check_for_fd_attrs (sm_ctxt, node, stmt, callee_fndecl, "fd_arg_read", DIRS_READ);
+
+ // Handle __attribute__((fd_arg_write))
+
+ check_for_fd_attrs (sm_ctxt, node, stmt, callee_fndecl, "fd_arg_write", DIRS_WRITE);
+
+ return true;
+ }
+
}
return false;
}
+void
+fd_state_machine::check_for_fd_attrs (
+ sm_context *sm_ctxt, const supernode *node, const gimple *stmt,
+ const tree callee_fndecl, const char *attr_name,
+ access_directions fd_attr_access_dir) const
+{
+
+ tree attrs = TYPE_ATTRIBUTES (TREE_TYPE (callee_fndecl));
+ attrs = lookup_attribute (attr_name, attrs);
+ if (!attrs)
+ return;
+
+ if (!TREE_VALUE (attrs))
+ return;
+
+ auto_bitmap argmap;
+
+ for (tree idx = TREE_VALUE (attrs); idx; idx = TREE_CHAIN (idx))
+ {
+ unsigned int val = TREE_INT_CST_LOW (TREE_VALUE (idx)) - 1;
+ bitmap_set_bit (argmap, val);
+ }
+ if (bitmap_empty_p (argmap))
+ return;
+
+ for (unsigned i = 0; i < gimple_call_num_args (stmt); i++)
+ {
+
+ unsigned int arg_idx = i;
+ tree arg = gimple_call_arg (stmt, arg_idx);
+ tree diag_arg = sm_ctxt->get_diagnostic_tree (arg);
+ state_t state = sm_ctxt->get_state (stmt, arg);
+ bool bit_set = bitmap_bit_p (argmap, arg_idx);
+ if (TREE_CODE (TREE_TYPE (arg)) != INTEGER_TYPE)
+ continue;
+ if (bit_set) // Check if arg_idx is marked by any of the file descriptor
+ // attributes
+ {
+
+ if (is_closed_fd_p (state))
+ {
+
+ sm_ctxt->warn (node, stmt, arg,
+ new fd_use_after_close (*this, diag_arg,
+ callee_fndecl, true,
+ arg_idx));
+ continue;
+ }
+
+ if (!(is_valid_fd_p (state) || (state == m_stop)))
+ {
+ if (!is_constant_fd_p (state))
+ sm_ctxt->warn (node, stmt, arg,
+ new fd_use_without_check (*this, diag_arg,
+ callee_fndecl, true,
+ arg_idx));
+ }
+
+ switch (fd_attr_access_dir)
+ {
+ case DIRS_READ_WRITE:
+ break;
+ case DIRS_READ:
+
+ if (is_writeonly_fd_p (state))
+ {
+ sm_ctxt->warn (
+ node, stmt, arg,
+ new fd_access_mode_mismatch (*this, diag_arg, DIRS_WRITE,
+ callee_fndecl, true, i));
+ }
+
+ break;
+ case DIRS_WRITE:
+
+ if (is_readonly_fd_p (state))
+ {
+ sm_ctxt->warn (
+ node, stmt, arg,
+ new fd_access_mode_mismatch (*this, diag_arg, DIRS_READ,
+ callee_fndecl, true, i));
+ }
+
+ break;
+ }
+ }
+ }
+}
+
+
void
fd_state_machine::on_open (sm_context *sm_ctxt, const supernode *node,
const gimple *stmt, const gcall *call) const
@@ -706,7 +899,7 @@ fd_state_machine::on_close (sm_context *sm_ctxt, const supernode *node,
if (is_closed_fd_p (state))
{
- sm_ctxt->warn (node, stmt, arg, new double_close (*this, diag_arg));
+ sm_ctxt->warn (node, stmt, arg, new fd_double_close (*this, diag_arg));
sm_ctxt->set_next_state (stmt, arg, m_stop);
}
}
@@ -715,21 +908,21 @@ fd_state_machine::on_read (sm_context *sm_ctxt, const supernode *node,
const gimple *stmt, const gcall *call,
const tree callee_fndecl) const
{
- check_for_open_fd (sm_ctxt, node, stmt, call, callee_fndecl, DIR_READ);
+ check_for_open_fd (sm_ctxt, node, stmt, call, callee_fndecl, DIRS_READ);
}
void
fd_state_machine::on_write (sm_context *sm_ctxt, const supernode *node,
const gimple *stmt, const gcall *call,
const tree callee_fndecl) const
{
- check_for_open_fd (sm_ctxt, node, stmt, call, callee_fndecl, DIR_WRITE);
+ check_for_open_fd (sm_ctxt, node, stmt, call, callee_fndecl, DIRS_WRITE);
}
void
fd_state_machine::check_for_open_fd (
sm_context *sm_ctxt, const supernode *node, const gimple *stmt,
const gcall *call, const tree callee_fndecl,
- enum access_direction callee_fndecl_dir) const
+ enum access_directions callee_fndecl_dir) const
{
tree arg = gimple_call_arg (call, 0);
tree diag_arg = sm_ctxt->get_diagnostic_tree (arg);
@@ -748,30 +941,32 @@ fd_state_machine::check_for_open_fd (
if (!is_constant_fd_p (state))
sm_ctxt->warn (
node, stmt, arg,
- new unchecked_use_of_fd (*this, diag_arg, callee_fndecl));
+ new fd_use_without_check (*this, diag_arg, callee_fndecl));
}
switch (callee_fndecl_dir)
{
- case DIR_READ:
+ case DIRS_READ:
if (is_writeonly_fd_p (state))
{
tree diag_arg = sm_ctxt->get_diagnostic_tree (arg);
sm_ctxt->warn (node, stmt, arg,
new fd_access_mode_mismatch (
- *this, diag_arg, DIR_WRITE, callee_fndecl));
+ *this, diag_arg, DIRS_WRITE, callee_fndecl));
}
break;
- case DIR_WRITE:
+ case DIRS_WRITE:
if (is_readonly_fd_p (state))
{
tree diag_arg = sm_ctxt->get_diagnostic_tree (arg);
sm_ctxt->warn (node, stmt, arg,
new fd_access_mode_mismatch (
- *this, diag_arg, DIR_READ, callee_fndecl));
+ *this, diag_arg, DIRS_READ, callee_fndecl));
}
break;
+ default:
+ gcc_unreachable ();
}
}
}
@@ -173,6 +173,7 @@ static tree handle_objc_nullability_attribute (tree *, tree, tree, int, bool *);
static tree handle_signed_bool_precision_attribute (tree *, tree, tree, int,
bool *);
static tree handle_retain_attribute (tree *, tree, tree, int, bool *);
+static tree handle_fd_arg_attribute (tree *, tree, tree, int, bool *);
/* Helper to define attribute exclusions. */
#define ATTR_EXCL(name, function, type, variable) \
@@ -426,7 +427,7 @@ const struct attribute_spec c_common_attribute_table[] =
{ "tls_model", 1, 1, true, false, false, false,
handle_tls_model_attribute, NULL },
{ "nonnull", 0, -1, false, true, true, false,
- handle_nonnull_attribute, NULL },
+ handle_nonnull_attribute, NULL },
{ "nonstring", 0, 0, true, false, false, false,
handle_nonstring_attribute, NULL },
{ "nothrow", 0, 0, true, false, false, false,
@@ -555,7 +556,13 @@ const struct attribute_spec c_common_attribute_table[] =
handle_dealloc_attribute, NULL },
{ "tainted_args", 0, 0, true, false, false, false,
handle_tainted_args_attribute, NULL },
- { NULL, 0, 0, false, false, false, false, NULL, NULL }
+ { NULL, 0, 0, false, false, false, false, NULL, NULL },
+ { "fd_arg", 1, 1, false, true, true, false,
+ handle_fd_arg_attribute, NULL},
+ { "fd_arg_read", 1, 1, false, true, true, false,
+ handle_fd_arg_attribute, NULL},
+ { "fd_arg_write", 1, 1, false, true, true, false,
+ handle_fd_arg_attribute, NULL},
};
/* Give the specifications for the format attributes, used by C and all
@@ -4521,6 +4528,31 @@ handle_nonnull_attribute (tree *node, tree name,
return NULL_TREE;
}
+/* Handle the "fd_arg", "fd_arg_read" and "fd_arg_write" attributes */
+
+static tree
+handle_fd_arg_attribute (tree *node, tree name, tree args,
+ int ARG_UNUSED (flags), bool *no_add_attrs)
+{
+ tree type = *node;
+ if (!args)
+ {
+ if (!prototype_p (type))
+ {
+ error ("%qE attribute without arguments on a non-prototype", name);
+ *no_add_attrs = true;
+ }
+ return NULL_TREE;
+ }
+
+ if (tree val = positional_argument (*node, name, TREE_VALUE (args),
+ INTEGER_TYPE))
+ return NULL_TREE;
+
+ *no_add_attrs = true;
+ return NULL_TREE;
+}
+
/* Handle the "nonstring" variable attribute. */
static tree
@@ -3007,6 +3007,40 @@ produced by @command{gold}.
For other linkers that cannot generate resolution file,
explicit @code{externally_visible} attributes are still necessary.
+@item fd_arg
+@cindex @code{fd_arg} function attribute
+The @code{fd_arg} attribute may be applied to a function that takes an open
+file descriptor at referenced argument @var{N}.
+
+It indicates that the passed filedescriptor must not have been closed.
+Therefore, when the analyzer is enabled with @option{-fanalyzer}, the
+analyzer may emit a @option{-Wanalyzer-fd-use-after-close} diagnostic
+if it detects a code path in which a function with this attribute is
+called with a closed file descriptor.
+
+The attribute also indicates that the file descriptor must have been checked for
+validity before usage. Therefore, analyzer may emit
+@option{-Wanalyzer-fd-use-without-check} diagnostic if it detects a code path in
+which a function with this attribute is called with a file descriptor that has
+not been checked for validity.
+
+@item fd_arg_read
+@cindex @code{fd_arg_read} function attribute
+The @code{fd_arg_read} is identical to @code{fd_arg}, but with the additional
+requirement that it might read from the file descriptor, and thus, the file
+descriptor must not have been opened as write-only.
+
+The analyzer may emit a @option{-Wanalyzer-access-mode-mismatch}
+diagnostic if it detects a code path in which a function with this
+attribute is called on a file descriptor opened with @code{O_WRONLY}.
+
+@item fd_arg_write
+@cindex @code{fd_arg_write} function attribute
+The @code{fd_arg_write} is identical to @code{fd_arg_read} except that the
+analyzer may emit a @option{-Wanalyzer-access-mode-mismatch} diagnostic if
+it detects a code path in which a function with this attribute is called on a
+file descriptor opened with @code{O_RDONLY}.
+
@item flatten
@cindex @code{flatten} function attribute
Generally, inlining into a function is limited. For a function marked with
new file mode 100644
@@ -0,0 +1,18 @@
+
+int not_a_fn __attribute__ ((fd_arg(1))); /* { dg-warning "'fd_arg' attribute only applies to function types" } */
+
+void f (char *p) __attribute__ ((fd_arg(1))); /* { dg-warning "'fd_arg' attribute argument value '1' refers to parameter type 'char \\\*'" } */
+
+
+int not_a_fn_b __attribute__ ((fd_arg_read(1))); /* { dg-warning "'fd_arg_read' attribute only applies to function types" } */
+
+void g (char *p) __attribute__ ((fd_arg_read(1))); /* { dg-warning "'fd_arg_read' attribute argument value '1' refers to parameter type 'char \\\*'" } */
+
+
+int not_a_fn_c __attribute__ ((fd_arg_write(1))); /* { dg-warning "'fd_arg_write' attribute only applies to function types" } */
+
+void f (char *p) __attribute__ ((fd_arg_write(1))); /* { dg-warning "'fd_arg_write' attribute argument value '1' refers to parameter type 'char \\\*'" } */
+
+
+void fn_a (int fd) __attribute__ ((fd_arg(0))); /* { dg-warning "'fd_arg' attribute argument value '0' does not refer to a function parameter" } */
+void fd_a_1 (int fd) __attribute__ ((fd_arg("notint"))); /* { dg-warning "'fd_arg' attribute argument has type 'char\\\[7\\\]'" } */
new file mode 100644
@@ -0,0 +1,53 @@
+int open(const char *, int mode);
+void close(int fd);
+int write (int fd, void *buf, int nbytes);
+int read (int fd, void *buf, int nbytes);
+
+#define O_RDONLY 0
+#define O_WRONLY 1
+#define O_RDWR 2
+
+void f (int fd) __attribute__((fd_arg(1))); /* { dg-message "argument 1 of 'f' must be an open file descriptor" } */
+
+void
+test_1 (const char *path)
+{
+ int fd = open (path, O_RDWR);
+ close(fd);
+ f(fd); /* { dg-warning "'f' on closed file descriptor 'fd'" } */
+ /* { dg-message "\\(3\\) 'f' on closed file descriptor 'fd'; 'close' was at \\(2\\)" "" { target *-*-* } .-1 } */
+}
+
+void g (int fd) __attribute__((fd_arg_read(1))); /* { dg-message "argument 1 of 'g' must be a read-only file descriptor" } */
+
+void
+test_2 (const char *path)
+{
+ int fd = open (path, O_WRONLY);
+ if (fd != -1)
+ {
+ g (fd); /* { dg-warning "'g' on 'write-only' file descriptor 'fd'" } */
+ }
+ close (fd);
+}
+
+void h (int fd) __attribute__((fd_arg_write(1))); /* { dg-message "argument 1 of 'h' must be a write-only file descriptor" } */
+void
+test_3 (const char *path)
+{
+ int fd = open (path, O_RDONLY);
+ if (fd != -1)
+ {
+ h (fd); /* { dg-warning "'h' on 'read-only' file descriptor 'fd'" } */
+ }
+ close(fd);
+}
+
+void ff (int fd) __attribute__((fd_arg(1))); /* { dg-message "argument 1 of 'ff' must be an open file descriptor" } */
+
+void test_4 (const char *path)
+{
+ int fd = open (path, O_RDWR);
+ ff (fd); /* { dg-warning "'ff' on possibly invalid file descriptor 'fd'" } */
+ close(fd);
+}
\ No newline at end of file
This patch adds three new function attributes to GCC that are used for static analysis of usage of file descriptors: 1) __attribute__ ((fd_arg(N))): The attributes may be applied to a function that takes on open file descriptor at refrenced argument N. It indicates that the passed filedescriptor must not have been closed. Therefore, when the analyzer is enabled with -fanalyzer, the analyzer may emit a -Wanalyzer-fd-use-after-close diagnostic if it detects a code path in which a function with this attribute is called with a closed file descriptor. The attribute also indicates that the file descriptor must have been checked for validity before usage. Therefore, analyzer may emit -Wanalyzer-fd-use-without-check diagnostic if it detects a code path in which a function with this attribute is called with a file descriptor that has not been checked for validity. 2) __attribute__((fd_arg_read(N))): The attribute is identical to fd_arg, but with the additional requirement that it might read from the file descriptor, and thus, the file descriptor must not have been opened as write-only. The analyzer may emit a -Wanalyzer-access-mode-mismatch diagnostic if it detects a code path in which a function with this attribute is called on a file descriptor opened with O_WRONLY. 3) __attribute__((fd_arg_write(N))): The attribute is identical to fd_arg_read except that the analyzer may emit a -Wanalyzer-access-mode-mismatch diagnostic if it detects a code path in which a function with this attribute is called on a file descriptor opened with O_RDONLY. gcc/analyzer/ChangeLog: * sm-fd.cc (fd_param_diagnostic): New diagnostic class. (fd_access_mode_mismatch): Change inheritance from fd_diagnostic to fd_param_diagnostic. Add new overloaded constructor. (fd_use_after_close): Likewise. (unchecked_use_of_fd): Likewise and also change name to fd_use_without_check. (double_close): Change name to fd_double_close. (enum access_directions): New. (fd_state_machine::on_stmt): Handle calls to function with the new three function attributes. (fd_state_machine::check_for_fd_attrs): New. (fd_state_machine::on_open): Use the new overloaded constructors of diagnostic classes. gcc/c-family/ChangeLog: * c-attribs.cc: (c_common_attribute_table): add three new attributes namely: fd_arg, fd_arg_read and fd_arg_write. (handle_fd_arg_attribute): New. gcc/ChangeLog: * doc/extend.texi: Add fd_arg, fd_arg_read and fd_arg_write under "Common Function Attributes" section. gcc/testsuite/ChangeLog: * gcc.dg/analyzer/fd-5.c: New test. * c-c++-common/attr-fd.c: New test. Signed-off-by: Immad Mir <mirimmad@outlook.com> --- gcc/analyzer/sm-fd.cc | 323 +++++++++++++++++++++------ gcc/c-family/c-attribs.cc | 36 ++- gcc/doc/extend.texi | 34 +++ gcc/testsuite/c-c++-common/attr-fd.c | 18 ++ gcc/testsuite/gcc.dg/analyzer/fd-5.c | 53 +++++ 5 files changed, 398 insertions(+), 66 deletions(-) create mode 100644 gcc/testsuite/c-c++-common/attr-fd.c create mode 100644 gcc/testsuite/gcc.dg/analyzer/fd-5.c