[clang] [clang][analyzer] Improve modeling of 'popen' and 'pclose' in StdLibraryFunctionsChecker (PR #78895)
Ben Shi via cfe-commits
cfe-commits at lists.llvm.org
Sun Jan 21 02:30:12 PST 2024
https://github.com/benshi001 created https://github.com/llvm/llvm-project/pull/78895
None
>From b093d705ee949227ec0f7fe23bb65d43c7f9e51f Mon Sep 17 00:00:00 2001
From: Ben Shi <bennshi at tencent.com>
Date: Sun, 21 Jan 2024 18:29:06 +0800
Subject: [PATCH] [clang][analyzer] Improve modeling of 'popen' and 'pclose' in
StdLibraryFunctionsChecker
---
.../Checkers/StdLibraryFunctionsChecker.cpp | 35 +++++++++++--------
.../Analysis/Inputs/system-header-simulator.h | 2 ++
.../Analysis/std-c-library-functions-POSIX.c | 4 +--
clang/test/Analysis/stream-errno.c | 25 +++++++++++++
4 files changed, 49 insertions(+), 17 deletions(-)
diff --git a/clang/lib/StaticAnalyzer/Checkers/StdLibraryFunctionsChecker.cpp b/clang/lib/StaticAnalyzer/Checkers/StdLibraryFunctionsChecker.cpp
index d0eb5091444f6b..4053a829bd7a7d 100644
--- a/clang/lib/StaticAnalyzer/Checkers/StdLibraryFunctionsChecker.cpp
+++ b/clang/lib/StaticAnalyzer/Checkers/StdLibraryFunctionsChecker.cpp
@@ -2202,6 +2202,16 @@ void StdLibraryFunctionsChecker::initFunctionSummaries(
.ArgConstraint(NotNull(ArgNo(1)))
.ArgConstraint(NotNull(ArgNo(2))));
+ // FILE *popen(const char *command, const char *type);
+ addToFunctionSummaryMap(
+ "popen",
+ Signature(ArgTypes{ConstCharPtrTy, ConstCharPtrTy}, RetType{FilePtrTy}),
+ Summary(NoEvalCall)
+ .Case({NotNull(Ret)}, ErrnoMustNotBeChecked, GenericSuccessMsg)
+ .Case({IsNull(Ret)}, ErrnoNEZeroIrrelevant, GenericFailureMsg)
+ .ArgConstraint(NotNull(ArgNo(0)))
+ .ArgConstraint(NotNull(ArgNo(1))));
+
// int fclose(FILE *stream);
addToFunctionSummaryMap(
"fclose", Signature(ArgTypes{FilePtrTy}, RetType{IntTy}),
@@ -2211,6 +2221,16 @@ void StdLibraryFunctionsChecker::initFunctionSummaries(
ErrnoNEZeroIrrelevant, GenericFailureMsg)
.ArgConstraint(NotNull(ArgNo(0))));
+ // int pclose(FILE *stream);
+ addToFunctionSummaryMap(
+ "pclose", Signature(ArgTypes{FilePtrTy}, RetType{IntTy}),
+ Summary(NoEvalCall)
+ .Case({ReturnValueCondition(WithinRange, {{0, IntMax}})},
+ ErrnoMustNotBeChecked, GenericSuccessMsg)
+ .Case({ReturnValueCondition(WithinRange, SingleValue(-1))},
+ ErrnoNEZeroIrrelevant, GenericFailureMsg)
+ .ArgConstraint(NotNull(ArgNo(0))));
+
// int ungetc(int c, FILE *stream);
addToFunctionSummaryMap(
"ungetc", Signature(ArgTypes{IntTy, FilePtrTy}, RetType{IntTy}),
@@ -2827,21 +2847,6 @@ void StdLibraryFunctionsChecker::initFunctionSummaries(
.ArgConstraint(
ArgumentCondition(0, WithinRange, Range(0, IntMax))));
- // FILE *popen(const char *command, const char *type);
- // FIXME: Improve for errno modeling.
- addToFunctionSummaryMap(
- "popen",
- Signature(ArgTypes{ConstCharPtrTy, ConstCharPtrTy}, RetType{FilePtrTy}),
- Summary(NoEvalCall)
- .ArgConstraint(NotNull(ArgNo(0)))
- .ArgConstraint(NotNull(ArgNo(1))));
-
- // int pclose(FILE *stream);
- // FIXME: Improve for errno modeling.
- addToFunctionSummaryMap(
- "pclose", Signature(ArgTypes{FilePtrTy}, RetType{IntTy}),
- Summary(NoEvalCall).ArgConstraint(NotNull(ArgNo(0))));
-
// int close(int fildes);
addToFunctionSummaryMap(
"close", Signature(ArgTypes{IntTy}, RetType{IntTy}),
diff --git a/clang/test/Analysis/Inputs/system-header-simulator.h b/clang/test/Analysis/Inputs/system-header-simulator.h
index f8e3e546a7aed5..c41f22fef388e1 100644
--- a/clang/test/Analysis/Inputs/system-header-simulator.h
+++ b/clang/test/Analysis/Inputs/system-header-simulator.h
@@ -47,7 +47,9 @@ FILE *fopen(const char *restrict path, const char *restrict mode);
FILE *fdopen(int fd, const char *mode);
FILE *tmpfile(void);
FILE *freopen(const char *restrict pathname, const char *restrict mode, FILE *restrict stream);
+FILE *popen(const char *command, const char *mode);
int fclose(FILE *fp);
+int pclose(FILE *stream);
size_t fread(void *restrict, size_t, size_t, FILE *restrict);
size_t fwrite(const void *restrict, size_t, size_t, FILE *restrict);
int fgetc(FILE *stream);
diff --git a/clang/test/Analysis/std-c-library-functions-POSIX.c b/clang/test/Analysis/std-c-library-functions-POSIX.c
index 51b136d9ba3567..03aa8e2e00a75d 100644
--- a/clang/test/Analysis/std-c-library-functions-POSIX.c
+++ b/clang/test/Analysis/std-c-library-functions-POSIX.c
@@ -20,7 +20,9 @@
// CHECK: Loaded summary for: FILE *fdopen(int fd, const char *mode)
// CHECK: Loaded summary for: FILE *tmpfile(void)
// CHECK: Loaded summary for: FILE *freopen(const char *restrict pathname, const char *restrict mode, FILE *restrict stream)
+// CHECK: Loaded summary for: FILE *popen(const char *command, const char *type)
// CHECK: Loaded summary for: int fclose(FILE *stream)
+// CHECK: Loaded summary for: int pclose(FILE *stream)
// CHECK: Loaded summary for: int fseek(FILE *stream, long offset, int whence)
// CHECK: Loaded summary for: int fseeko(FILE *stream, off_t offset, int whence)
// CHECK: Loaded summary for: off_t ftello(FILE *stream)
@@ -74,8 +76,6 @@
// CHECK: Loaded summary for: DIR *opendir(const char *name)
// CHECK: Loaded summary for: DIR *fdopendir(int fd)
// CHECK: Loaded summary for: int isatty(int fildes)
-// CHECK: Loaded summary for: FILE *popen(const char *command, const char *type)
-// CHECK: Loaded summary for: int pclose(FILE *stream)
// CHECK: Loaded summary for: int close(int fildes)
// CHECK: Loaded summary for: long fpathconf(int fildes, int name)
// CHECK: Loaded summary for: long pathconf(const char *path, int name)
diff --git a/clang/test/Analysis/stream-errno.c b/clang/test/Analysis/stream-errno.c
index fab6a58b3275a8..44bf949673082d 100644
--- a/clang/test/Analysis/stream-errno.c
+++ b/clang/test/Analysis/stream-errno.c
@@ -51,6 +51,17 @@ void check_freopen(void) {
if (errno) {} // expected-warning{{An undefined value may be read from 'errno'}}
}
+void check_popen(void) {
+ FILE *F = popen("xxx", "r");
+ if (!F) {
+ clang_analyzer_eval(errno != 0); // expected-warning{{TRUE}}
+ if (errno) {} // no-warning
+ } else {
+ if (errno) {} // expected-warning{{An undefined value may be read from 'errno' [unix.Errno]}}
+ pclose(F);
+ }
+}
+
void check_fclose(void) {
FILE *F = tmpfile();
if (!F)
@@ -64,6 +75,20 @@ void check_fclose(void) {
if (errno) {} // expected-warning{{An undefined value may be read from 'errno'}}
}
+void check_pclose(void) {
+ FILE *F = popen("xx", "w");
+ if (!F)
+ return;
+ int Ret = pclose(F);
+ if (Ret == -1) {
+ clang_analyzer_eval(errno != 0); // expected-warning{{TRUE}}
+ if (errno) {} // no-warning
+ } else {
+ clang_analyzer_eval(Ret >= 0); // expected-warning{{TRUE}}
+ if (errno) {} // expected-warning{{An undefined value may be read from 'errno'}}
+ }
+}
+
void check_fread_size0(void) {
char Buf[10];
FILE *F = tmpfile();
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