Fix memory leaks during "tail -r" of an irregular file

* Rewrite r_buf to use standard tail queues instead of a hand-rolled
  circular linked list. Free dynamic allocations when done.
* Remove an optimization for the case where the file is a multiple of 128KB
  in size and there is a scarcity of memory.
* Add ATF tests for "tail -r" and its variants.

Reported by:	Valgrind
Reviewed by:	ngie
MFC after:	4 weeks
Sponsored by:	Spectra Logic Corp
Differential Revision:	https://reviews.freebsd.org/D9067
This commit is contained in:
Alan Somers 2017-01-10 20:43:32 +00:00
parent 442f47d697
commit cdb7a6fc42
Notes: svn2git 2020-12-20 02:59:44 +00:00
svn path=/head/; revision=311895
5 changed files with 311 additions and 77 deletions

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@ -644,6 +644,8 @@
..
soelim
..
tail
..
tar
..
timeout

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@ -1,7 +1,13 @@
# $FreeBSD$
# @(#)Makefile 8.1 (Berkeley) 6/6/93
.include <src.opts.mk>
PROG= tail
SRCS= forward.c misc.c read.c reverse.c tail.c
.if ${MK_TESTS} != "no"
SUBDIR+= tests
.endif
.include <bsd.prog.mk>

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@ -40,6 +40,7 @@ static char sccsid[] = "@(#)reverse.c 8.1 (Berkeley) 6/6/93";
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/queue.h>
#include <sys/stat.h>
#include <sys/mman.h>
@ -169,12 +170,12 @@ r_reg(FILE *fp, const char *fn, enum STYLE style, off_t off, struct stat *sbp)
ierr(fn);
}
typedef struct bf {
struct bf *next;
struct bf *prev;
int len;
char *l;
} BF;
static const size_t bsz = 128 * 1024;
typedef struct bfelem {
TAILQ_ENTRY(bfelem) entries;
size_t len;
char l[bsz];
} bfelem_t;
/*
* r_buf -- display a non-regular file in reverse order by line.
@ -189,64 +190,42 @@ typedef struct bf {
static void
r_buf(FILE *fp, const char *fn)
{
BF *mark, *tl, *tr;
int ch, len, llen;
struct bfelem *tl, *temp, *first = NULL;
size_t len, llen;
char *p;
off_t enomem;
off_t enomem = 0;
TAILQ_HEAD(bfhead, bfelem) head;
tl = NULL;
#define BSZ (128 * 1024)
for (mark = NULL, enomem = 0;;) {
TAILQ_INIT(&head);
while (!feof(fp)) {
/*
* Allocate a new block and link it into place in a doubly
* linked list. If out of memory, toss the LRU block and
* keep going.
*/
if (enomem || (tl = malloc(sizeof(BF))) == NULL ||
(tl->l = malloc(BSZ)) == NULL) {
if (!mark)
while ((tl = malloc(sizeof(bfelem_t))) == NULL) {
first = TAILQ_FIRST(&head);
if (TAILQ_EMPTY(&head))
err(1, "malloc");
if (enomem)
tl = tl->next;
else {
if (tl)
free(tl);
tl = mark;
}
enomem += tl->len;
} else if (mark) {
tl->next = mark;
tl->prev = mark->prev;
mark->prev->next = tl;
mark->prev = tl;
} else {
mark = tl;
mark->next = mark->prev = mark;
enomem += first->len;
TAILQ_REMOVE(&head, first, entries);
free(first);
}
TAILQ_INSERT_TAIL(&head, tl, entries);
/* Fill the block with input data. */
for (p = tl->l, len = 0;
len < BSZ && (ch = getc(fp)) != EOF; ++len)
*p++ = ch;
if (ferror(fp)) {
ierr(fn);
return;
}
/*
* If no input data for this block and we tossed some data,
* recover it.
*/
if (!len && enomem) {
enomem -= tl->len;
tl = tl->prev;
break;
len = 0;
while ((!feof(fp)) && len < bsz) {
p = tl->l + len;
len += fread(p, 1, bsz - len, fp);
if (ferror(fp)) {
ierr(fn);
return;
}
}
tl->len = len;
if (ch == EOF)
break;
}
if (enomem) {
@ -255,37 +234,44 @@ r_buf(FILE *fp, const char *fn)
}
/*
* Step through the blocks in the reverse order read. The last char
* is special, ignore whether newline or not.
* Now print the lines in reverse order
* Outline:
* Scan backward for "\n",
* print forward to the end of the buffers
* free any buffers that start after the "\n" just found
* Loop
*/
for (mark = tl;;) {
for (p = tl->l + (len = tl->len) - 1, llen = 0; len--;
--p, ++llen)
if (*p == '\n') {
if (llen) {
tl = TAILQ_LAST(&head, bfhead);
first = TAILQ_FIRST(&head);
while (tl != NULL) {
for (p = tl->l + tl->len - 1, llen = 0; p >= tl->l;
--p, ++llen) {
int start = (tl == first && p == tl->l);
if ((*p == '\n') || start) {
struct bfelem *tr;
if (start && len)
WR(p, llen + 1);
else if (llen)
WR(p + 1, llen);
llen = 0;
}
if (tl == mark)
continue;
for (tr = tl->next; tr->len; tr = tr->next) {
WR(tr->l, tr->len);
tr->len = 0;
if (tr == mark)
break;
tr = TAILQ_NEXT(tl, entries);
llen = 0;
if (tr != NULL) {
TAILQ_FOREACH_FROM_SAFE(tr, &head,
entries, temp) {
if (tr->len)
WR(&tr->l, tr->len);
TAILQ_REMOVE(&head, tr,
entries);
free(tr);
}
}
}
}
tl->len = llen;
if ((tl = tl->prev) == mark)
break;
}
tl = tl->next;
if (tl->len) {
WR(tl->l, tl->len);
tl->len = 0;
}
while ((tl = tl->next)->len) {
WR(tl->l, tl->len);
tl->len = 0;
tl = TAILQ_PREV(tl, bfhead, entries);
}
TAILQ_REMOVE(&head, first, entries);
free(first);
}

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@ -0,0 +1,7 @@
# $FreeBSD$
PACKAGE= tests
ATF_TESTS_SH= tail_test
.include <bsd.test.mk>

233
usr.bin/tail/tests/tail_test.sh Executable file
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@ -0,0 +1,233 @@
# Copyright (c) 2016 Alan Somers
# 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.
#
# THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``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 OR CONTRIBUTORS 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.
#
# $FreeBSD$
atf_test_case empty_r
empty_r_head()
{
atf_set "descr" "Reverse an empty file"
}
empty_r_body()
{
touch infile expectfile
tail -r infile > outfile
tail -r < infile > outpipe
atf_check cmp expectfile outfile
atf_check cmp expectfile outpipe
}
atf_test_case file_r
file_r_head()
{
atf_set "descr" "Reverse a file"
}
file_r_body()
{
cat > infile <<HERE
This is the first line
This is the second line
This is the third line
HERE
cat > expectfile << HERE
This is the third line
This is the second line
This is the first line
HERE
tail -r infile > outfile
tail -r < infile > outpipe
atf_check cmp expectfile outfile
atf_check cmp expectfile outpipe
}
atf_test_case file_rn2
file_rn2_head()
{
atf_set "descr" "Reverse the last two lines of a file"
}
file_rn2_body()
{
cat > infile <<HERE
This is the first line
This is the second line
This is the third line
HERE
cat > expectfile << HERE
This is the third line
This is the second line
HERE
tail -rn2 infile > outfile
tail -rn2 < infile > outpipe
atf_check cmp expectfile outfile
atf_check cmp expectfile outpipe
}
atf_test_case file_rc28
file_rc28_head()
{
atf_set "descr" "Reverse a file and display the last 28 characters"
}
file_rc28_body()
{
cat > infile <<HERE
This is the first line
This is the second line
This is the third line
HERE
cat > expectfile << HERE
This is the third line
line
HERE
tail -rc28 infile > outfile
tail -rc28 < infile > outpipe
atf_check cmp expectfile outfile
atf_check cmp expectfile outpipe
}
atf_test_case longfile_r
longfile_r_head()
{
atf_set "descr" "Reverse a long file"
}
longfile_r_body()
{
jot -w "%0511d" 1030 0 > infile
jot -w "%0511d" 1030 1029 0 -1 > expectfile
tail -r infile > outfile
tail -r < infile > outpipe
atf_check cmp expectfile outfile
atf_check cmp expectfile outpipe
}
atf_test_case longfile_r_enomem
longfile_r_enomem_head()
{
atf_set "descr" "Reverse a file that's too long to store in RAM"
}
longfile_r_enomem_body()
{
# When we reverse a file that's too long for RAM, tail should drop the
# first part and just print what it can. We'll check that the last
# part is ok
{
ulimit -v 32768 || atf_skip "Can't adjust ulimit"
jot -w "%01023d" 32768 0 | tail -r > outfile ;
}
if [ "$?" -ne 1 ]; then
atf_skip "Didn't get ENOMEM. Adjust test parameters"
fi
# We don't know how much of the input we dropped. So just check that
# the first ten lines of tail's output are the same as the last ten of
# the input
jot -w "%01023d" 10 32767 0 -1 > expectfile
head -n 10 outfile > outtrunc
diff expectfile outtrunc
atf_check cmp expectfile outtrunc
}
atf_test_case longfile_r_longlines
longfile_r_longlines_head()
{
atf_set "descr" "Reverse a long file with extremely long lines"
}
longfile_r_longlines_body()
{
jot -s " " -w "%07d" 18000 0 > infile
jot -s " " -w "%07d" 18000 18000 >> infile
jot -s " " -w "%07d" 18000 36000 >> infile
jot -s " " -w "%07d" 18000 36000 > expectfile
jot -s " " -w "%07d" 18000 18000 >> expectfile
jot -s " " -w "%07d" 18000 0 >> expectfile
tail -r infile > outfile
tail -r < infile > outpipe
atf_check cmp expectfile outfile
atf_check cmp expectfile outpipe
}
atf_test_case longfile_rc135782
longfile_rc135782_head()
{
atf_set "descr" "Reverse a long file and print the last 135,782 bytes"
}
longfile_rc135782_body()
{
jot -w "%063d" 9000 0 > infile
jot -w "%063d" 2121 8999 0 -1 > expectfile
echo "0000000000000000000000000000000006878" >> expectfile
tail -rc135782 infile > outfile
tail -rc135782 < infile > outpipe
atf_check cmp expectfile outfile
atf_check cmp expectfile outpipe
}
atf_test_case longfile_rc145782_longlines
longfile_rc145782_longlines_head()
{
atf_set "descr" "Reverse a long file with extremely long lines and print the last 145,782 bytes"
}
longfile_rc145782_longlines_body()
{
jot -s " " -w "%07d" 18000 0 > infile
jot -s " " -w "%07d" 18000 18000 >> infile
jot -s " " -w "%07d" 18000 36000 >> infile
jot -s " " -w "%07d" 18000 36000 > expectfile
echo -n "35777 " >> expectfile
jot -s " " -w "%07d" 222 35778 >> expectfile
tail -rc145782 infile > outfile
tail -rc145782 < infile > outpipe
atf_check cmp expectfile outfile
atf_check cmp expectfile outpipe
}
atf_test_case longfile_rn2500
longfile_rn2500_head()
{
atf_set "descr" "Reverse a long file and print the last 2,500 lines"
}
longfile_rn2500_body()
{
jot -w "%063d" 9000 0 > infile
jot -w "%063d" 2500 8999 0 -1 > expectfile
tail -rn2500 infile > outfile
tail -rn2500 < infile > outpipe
atf_check cmp expectfile outfile
atf_check cmp expectfile outpipe
}
atf_init_test_cases()
{
atf_add_test_case empty_r
atf_add_test_case file_r
atf_add_test_case file_rc28
atf_add_test_case file_rn2
# The longfile tests are designed to exercise behavior in r_buf(),
# which operates on 128KB blocks
atf_add_test_case longfile_r
atf_add_test_case longfile_r_enomem
atf_add_test_case longfile_r_longlines
atf_add_test_case longfile_rc135782
atf_add_test_case longfile_rc145782_longlines
atf_add_test_case longfile_rn2500
}