From a5406364ac949f91867352cb2ae867629f083c5b Mon Sep 17 00:00:00 2001 From: Florian Weimer Date: Mon, 18 Feb 2019 11:49:54 +0100 Subject: libio: Eliminate _IO_stdin, _IO_stdout, _IO_stderr These variables are only used to determine if a stdio stream is a pre-allocated stream, but it is possible to do so by comparing a FILE * to all pre-allocated stream objects. As a result, it is not necessary to keep those pointers in separate variables. Behavior with symbol interposition is unchanged because _IO_stdin_, _IO_stdout_, _IO_stderr_ are exported, and refer to objects outside of libc if symbol interposition or copy relocations are involved. (The removed variables _IO_stdin, _IO_stdout, _IO_stderr were not exported, of course.) --- libio/iofclose.c | 7 +------ libio/iofwide.c | 3 +-- libio/iolibio.h | 2 -- libio/libio.h | 3 --- libio/libioP.h | 30 +++++++++++++++++++++++++++++- libio/oldfileops.c | 5 +---- libio/oldiofclose.c | 7 +------ libio/oldstdfiles.c | 18 +++++++----------- libio/stdfiles.c | 9 ++++----- libio/stdio.c | 11 ----------- 10 files changed, 44 insertions(+), 51 deletions(-) (limited to 'libio') diff --git a/libio/iofclose.c b/libio/iofclose.c index 9b39a6cc4e..8a80dd0b78 100644 --- a/libio/iofclose.c +++ b/libio/iofclose.c @@ -71,12 +71,7 @@ _IO_new_fclose (FILE *fp) if (_IO_have_backup (fp)) _IO_free_backup_area (fp); } - if (fp != _IO_stdin && fp != _IO_stdout && fp != _IO_stderr) - { - fp->_flags = 0; - free(fp); - } - + _IO_deallocate_file (fp); return status; } diff --git a/libio/iofwide.c b/libio/iofwide.c index 6676ad5e53..247cfde3d0 100644 --- a/libio/iofwide.c +++ b/libio/iofwide.c @@ -87,8 +87,7 @@ _IO_fwide (FILE *fp, int mode) mode = mode < 0 ? -1 : (mode == 0 ? 0 : 1); #if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_1) - if (__builtin_expect (&_IO_stdin_used == NULL, 0) - && (fp == _IO_stdin || fp == _IO_stdout || fp == _IO_stderr)) + if (__glibc_unlikely (&_IO_stdin_used == NULL) && _IO_legacy_file (fp)) /* This is for a stream in the glibc 2.0 format. */ return -1; #endif diff --git a/libio/iolibio.h b/libio/iolibio.h index 2642d71e4f..9561833655 100644 --- a/libio/iolibio.h +++ b/libio/iolibio.h @@ -58,8 +58,6 @@ extern int _IO_vsscanf (const char *, const char *, __gnuc_va_list) __THROW; == _IO_pos_BAD ? EOF : 0) #define _IO_rewind(FILE) \ (void) _IO_seekoff_unlocked (FILE, 0, 0, _IOS_INPUT|_IOS_OUTPUT) -#define _IO_vprintf(FORMAT, ARGS) \ - _IO_vfprintf (_IO_stdout, FORMAT, ARGS) #define _IO_freopen(FILENAME, MODE, FP) \ (_IO_file_close_it (FP), \ _IO_file_fopen (FP, FILENAME, MODE, 1)) diff --git a/libio/libio.h b/libio/libio.h index 9c08c7eba1..c38095ff77 100644 --- a/libio/libio.h +++ b/libio/libio.h @@ -185,9 +185,6 @@ struct _IO_FILE_plus; extern struct _IO_FILE_plus _IO_2_1_stdin_; extern struct _IO_FILE_plus _IO_2_1_stdout_; extern struct _IO_FILE_plus _IO_2_1_stderr_; -extern FILE *_IO_stdin attribute_hidden; -extern FILE *_IO_stdout attribute_hidden; -extern FILE *_IO_stderr attribute_hidden; struct _IO_cookie_file; diff --git a/libio/libioP.h b/libio/libioP.h index 8c75f15167..1c434ec3a1 100644 --- a/libio/libioP.h +++ b/libio/libioP.h @@ -817,7 +817,35 @@ extern int _IO_vscanf (const char *, va_list) __THROW; # endif #endif -extern struct _IO_fake_stdiobuf _IO_stdin_buf, _IO_stdout_buf, _IO_stderr_buf; +#if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_1) +/* See oldstdfiles.c. These are the old stream variables. */ +extern struct _IO_FILE_plus _IO_stdin_; +extern struct _IO_FILE_plus _IO_stdout_; +extern struct _IO_FILE_plus _IO_stderr_; + +static inline bool +_IO_legacy_file (FILE *fp) +{ + return fp == (FILE *) &_IO_stdin_ || fp == (FILE *) &_IO_stdout_ + || fp == (FILE *) &_IO_stderr_; +} +#endif + +/* Deallocate a stream if it is heap-allocated. Preallocated + stdin/stdout/stderr streams are not deallocated. */ +static inline void +_IO_deallocate_file (FILE *fp) +{ + /* The current stream variables. */ + if (fp == (FILE *) &_IO_2_1_stdin_ || fp == (FILE *) &_IO_2_1_stdout_ + || fp == (FILE *) &_IO_2_1_stderr_) + return; +#if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_1) + if (_IO_legacy_file (fp)) + return; +#endif + free (fp); +} #ifdef IO_DEBUG # define CHECK_FILE(FILE, RET) do { \ diff --git a/libio/oldfileops.c b/libio/oldfileops.c index 4d6c5e3fe7..5c319beacd 100644 --- a/libio/oldfileops.c +++ b/libio/oldfileops.c @@ -109,10 +109,7 @@ _IO_old_file_init_internal (struct _IO_FILE_plus *fp) - (int) sizeof (struct _IO_FILE_complete)); fp->file._fileno = -1; - if (__builtin_expect (&_IO_stdin_used != NULL, 1) - || (fp != (struct _IO_FILE_plus *) _IO_stdin - && fp != (struct _IO_FILE_plus *) _IO_stdout - && fp != (struct _IO_FILE_plus *) _IO_stderr)) + if (&_IO_stdin_used != NULL || !_IO_legacy_file ((FILE *) fp)) /* The object is dynamically allocated and large enough. Initialize the _mode element as well. */ ((struct _IO_FILE_complete *) fp)->_mode = -1; diff --git a/libio/oldiofclose.c b/libio/oldiofclose.c index e4cbf88566..be5044c3bd 100644 --- a/libio/oldiofclose.c +++ b/libio/oldiofclose.c @@ -58,12 +58,7 @@ _IO_old_fclose (FILE *fp) _IO_FINISH (fp); if (_IO_have_backup (fp)) _IO_free_backup_area (fp); - if (fp != _IO_stdin && fp != _IO_stdout && fp != _IO_stderr) - { - fp->_flags = 0; - free(fp); - } - + _IO_deallocate_file (fp); return status; } diff --git a/libio/oldstdfiles.c b/libio/oldstdfiles.c index 524e260b7e..2b861cd754 100644 --- a/libio/oldstdfiles.c +++ b/libio/oldstdfiles.c @@ -27,11 +27,8 @@ #include #if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_1) -/* This file provides definitions of _IO_stdin, _IO_stdout, and _IO_stderr - for C code. Compare stdstreams.cc. - (The difference is that here the vtable field is set to 0, - so the objects defined are not valid C++ objects. On the other - hand, we don't need a C++ compiler to build this file.) */ +/* This file provides legacy definitions of _IO_stdin_, _IO_stdout_, + and _IO_stderr_. See stdfiles.c for the current definitions. */ #define _IO_USE_OLD_IO_FILE #include "libioP.h" @@ -78,13 +75,12 @@ _IO_check_libio (void) if (&_IO_stdin_used == NULL) { /* We are using the old one. */ - _IO_stdin = stdin = (FILE *) &_IO_stdin_; - _IO_stdout = stdout = (FILE *) &_IO_stdout_; - _IO_stderr = stderr = (FILE *) &_IO_stderr_; + stdin = (FILE *) &_IO_stdin_; + stdout = (FILE *) &_IO_stdout_; + stderr = (FILE *) &_IO_stderr_; _IO_list_all = &_IO_stderr_; - _IO_stdin->_vtable_offset = _IO_stdout->_vtable_offset = - _IO_stderr->_vtable_offset = stdin->_vtable_offset = - stdout->_vtable_offset = stderr->_vtable_offset = + stdin->_vtable_offset = stdout->_vtable_offset + = stderr->_vtable_offset = ((int) sizeof (struct _IO_FILE) - (int) sizeof (struct _IO_FILE_complete)); } diff --git a/libio/stdfiles.c b/libio/stdfiles.c index 605e006474..9c779b47eb 100644 --- a/libio/stdfiles.c +++ b/libio/stdfiles.c @@ -25,11 +25,10 @@ in files containing the exception. */ -/* This file provides definitions of _IO_stdin, _IO_stdout, and _IO_stderr - for C code. Compare stdstreams.cc. - (The difference is that here the vtable field is set to 0, - so the objects defined are not valid C++ objects. On the other - hand, we don't need a C++ compiler to build this file.) */ +/* This file provides definitions of _IO_2_1_stdin_, _IO_2_1_stdout_, + and _IO_2_1_stderr_, the default values of stdin, stdout, stderr. + See oldstdfiles.c for glibc 2.0 legacy definitions without wide + character support. */ #include "libioP.h" diff --git a/libio/stdio.c b/libio/stdio.c index 1294d2842e..522de44a27 100644 --- a/libio/stdio.c +++ b/libio/stdio.c @@ -33,14 +33,3 @@ FILE *stdin = (FILE *) &_IO_2_1_stdin_; FILE *stdout = (FILE *) &_IO_2_1_stdout_; FILE *stderr = (FILE *) &_IO_2_1_stderr_; - -#undef _IO_stdin -#undef _IO_stdout -#undef _IO_stderr -#define AL(name) AL2 (name, _IO_##name) -#define AL2(name, al) \ - extern __typeof (name) al __attribute__ ((alias (#name), \ - visibility ("hidden"))) -AL(stdin); -AL(stdout); -AL(stderr); -- cgit 1.4.1