diff options
Diffstat (limited to 'ungetc-Fix-backup-buffer-leak-on-program-exit-BZ-278.patch')
| -rw-r--r-- | ungetc-Fix-backup-buffer-leak-on-program-exit-BZ-278.patch | 145 |
1 files changed, 145 insertions, 0 deletions
diff --git a/ungetc-Fix-backup-buffer-leak-on-program-exit-BZ-278.patch b/ungetc-Fix-backup-buffer-leak-on-program-exit-BZ-278.patch new file mode 100644 index 0000000..9faa58c --- /dev/null +++ b/ungetc-Fix-backup-buffer-leak-on-program-exit-BZ-278.patch @@ -0,0 +1,145 @@ +From b9f72bd5de931eac39219018c2fa319a449bb2cf Mon Sep 17 00:00:00 2001 +From: Siddhesh Poyarekar <siddhesh@sourceware.org> +Date: Tue, 13 Aug 2024 21:08:49 -0400 +Subject: [PATCH] ungetc: Fix backup buffer leak on program exit [BZ + #27821] + +If a file descriptor is left unclosed and is cleaned up by _IO_cleanup +on exit, its backup buffer remains unfreed, registering as a leak in +valgrind. This is not strictly an issue since (1) the program should +ideally be closing the stream once it's not in use and (2) the program +is about to exit anyway, so keeping the backup buffer around a wee bit +longer isn't a real problem. Free it anyway to keep valgrind happy +when the streams in question are the standard ones, i.e. stdout, stdin +or stderr. + +Also, the _IO_have_backup macro checks for _IO_save_base, +which is a roundabout way to check for a backup buffer instead of +directly looking for _IO_backup_base. The roundabout check breaks when +the main get area has not been used and user pushes a char into the +backup buffer with ungetc. Fix this to use the _IO_backup_base +directly. + +Signed-off-by: Siddhesh Poyarekar <siddhesh@sourceware.org> +Reviewed-by: Carlos O'Donell <carlos@redhat.com> +(cherry picked from commit 3e1d8d1d1dca24ae90df2ea826a8916896fc7e77) +--- + libio/genops.c | 6 ++++++ + libio/libioP.h | 4 ++-- + stdio-common/Makefile | 7 +++++++ + stdio-common/tst-ungetc-leak.c | 32 ++++++++++++++++++++++++++++++++ + 4 files changed, 47 insertions(+), 2 deletions(-) + create mode 100644 stdio-common/tst-ungetc-leak.c + +diff --git a/libio/genops.c b/libio/genops.c +index c673c0acec..fb06245467 100644 +--- a/libio/genops.c ++++ b/libio/genops.c +@@ -789,6 +789,12 @@ _IO_unbuffer_all (void) + legacy = 1; + #endif + ++ /* Free up the backup area if it was ever allocated. */ ++ if (_IO_have_backup (fp)) ++ _IO_free_backup_area (fp); ++ if (fp->_mode > 0 && _IO_have_wbackup (fp)) ++ _IO_free_wbackup_area (fp); ++ + if (! (fp->_flags & _IO_UNBUFFERED) + /* Iff stream is un-orientated, it wasn't used. */ + && (legacy || fp->_mode != 0)) +diff --git a/libio/libioP.h b/libio/libioP.h +index 745278e076..e75ee770bc 100644 +--- a/libio/libioP.h ++++ b/libio/libioP.h +@@ -577,8 +577,8 @@ extern void _IO_old_init (FILE *fp, int flags) __THROW; + ((__fp)->_wide_data->_IO_write_base \ + = (__fp)->_wide_data->_IO_write_ptr = __p, \ + (__fp)->_wide_data->_IO_write_end = (__ep)) +-#define _IO_have_backup(fp) ((fp)->_IO_save_base != NULL) +-#define _IO_have_wbackup(fp) ((fp)->_wide_data->_IO_save_base != NULL) ++#define _IO_have_backup(fp) ((fp)->_IO_backup_base != NULL) ++#define _IO_have_wbackup(fp) ((fp)->_wide_data->_IO_backup_base != NULL) + #define _IO_in_backup(fp) ((fp)->_flags & _IO_IN_BACKUP) + #define _IO_have_markers(fp) ((fp)->_markers != NULL) + #define _IO_blen(fp) ((fp)->_IO_buf_end - (fp)->_IO_buf_base) +diff --git a/stdio-common/Makefile b/stdio-common/Makefile +index 2bcbaf754a..381040570b 100644 +--- a/stdio-common/Makefile ++++ b/stdio-common/Makefile +@@ -256,6 +256,7 @@ tests := \ + tst-swscanf \ + tst-tmpnam \ + tst-ungetc \ ++ tst-ungetc-leak \ + tst-unlockedio \ + tst-vfprintf-mbs-prec \ + tst-vfprintf-user-type \ +@@ -300,6 +301,7 @@ tests-special += \ + $(objpfx)tst-printfsz-islongdouble.out \ + $(objpfx)tst-setvbuf1-cmp.out \ + $(objpfx)tst-unbputc.out \ ++ $(objpfx)tst-ungetc-leak-mem.out \ + $(objpfx)tst-vfprintf-width-prec-mem.out \ + # tests-special + +@@ -314,6 +316,8 @@ generated += \ + tst-printf-fp-leak-mem.out \ + tst-printf-fp-leak.mtrace \ + tst-scanf-bz27650.mtrace \ ++ tst-ungetc-leak-mem.out \ ++ tst-ungetc-leak.mtrace \ + tst-vfprintf-width-prec-mem.out \ + tst-vfprintf-width-prec.mtrace \ + # generated +@@ -403,6 +407,9 @@ tst-printf-fp-leak-ENV = \ + tst-scanf-bz27650-ENV = \ + MALLOC_TRACE=$(objpfx)tst-scanf-bz27650.mtrace \ + LD_PRELOAD=$(common-objpfx)malloc/libc_malloc_debug.so ++tst-ungetc-leak-ENV = \ ++ MALLOC_TRACE=$(objpfx)tst-ungetc-leak.mtrace \ ++ LD_PRELOAD=$(common-objpfx)malloc/libc_malloc_debug.so + + $(objpfx)tst-unbputc.out: tst-unbputc.sh $(objpfx)tst-unbputc + $(SHELL) $< $(common-objpfx) '$(test-program-prefix)'; \ +diff --git a/stdio-common/tst-ungetc-leak.c b/stdio-common/tst-ungetc-leak.c +new file mode 100644 +index 0000000000..6c5152b43f +--- /dev/null ++++ b/stdio-common/tst-ungetc-leak.c +@@ -0,0 +1,32 @@ ++/* Test for memory leak with ungetc when stream is unused. ++ Copyright The GNU Toolchain Authors. ++ This file is part of the GNU C Library. ++ ++ The GNU C Library is free software; you can redistribute it and/or ++ modify it under the terms of the GNU Lesser General Public ++ License as published by the Free Software Foundation; either ++ version 2.1 of the License, or (at your option) any later version. ++ ++ The GNU C Library is distributed in the hope that it will be useful, ++ but WITHOUT ANY WARRANTY; without even the implied warranty of ++ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU ++ Lesser General Public License for more details. ++ ++ You should have received a copy of the GNU Lesser General Public ++ License along with the GNU C Library; if not, see ++ <https://www.gnu.org/licenses/>. */ ++ ++#include <stdio.h> ++#include <mcheck.h> ++#include <support/check.h> ++#include <support/support.h> ++ ++static int ++do_test (void) ++{ ++ mtrace (); ++ TEST_COMPARE (ungetc('y', stdin), 'y'); ++ return 0; ++} ++ ++#include <support/test-driver.c> +-- +2.33.0 + |