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New option --no-dereference.

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* src/diff.h (no_dereference_symlinks): New variable.
* src/diff.c: Include xreadlink.h.
(longopts): Add --no-dereference option.
(main): Accept --no-dereference option.
(option_help_msgid): Mention the --no-dereference option.
(compare_files): If no_dereference_symlinks is true, use lstat()
instead of stat(). Compare symbolic links by comparing their values.
* bootstrap.conf (gnulib_modules): Add lstat, stat, xreadlink.
* doc/diffutils.texi (Comparing Directories, diff Options): Mention the
--no-dereference option.
* tests/no-dereference: New file.
* tests/Makefile.am (TESTS): Add it.
This commit is contained in:
Bruno Haible 2012-01-07 00:57:29 +01:00
parent 45110a7927
commit e3324651cc
6 changed files with 257 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
bootstrap.conf
View File

@ -48,6 +48,7 @@ hard-locale
inttostr
inttypes
largefile
lstat
maintainer-makefile
manywarnings
mbrtowc
@ -60,6 +61,7 @@ regex
sh-quote
signal
sigprocmask
stat
stat-macros
stat-time
stdint
@ -77,6 +79,7 @@ version-etc-fsf
wcwidth
xalloc
xfreopen
xreadlink
xstrtoumax
'

10
doc/diffutils.texi
View File

@ -1846,6 +1846,13 @@ is specified while the @option{--ignore-file-name-case} option is in
effect, case is ignored when excluding file names matching the
specified patterns.
To avoid that @command{diff} follows symbolic links, use the
@c later: @option{--no-dereference} (@option{-P}).
@option{--no-dereference}.
When this option is in use,
symbolic links will be treated like a special kind of files, rather than
comparing the target of each symbolic link.
@node Adjusting Output
@chapter Making @command{diff} Output Prettier
@ -3848,6 +3855,9 @@ file in if-then-else format. @xref{Line Group Formats}.
Use @var{format} to output a line taken from just the second file in
if-then-else format. @xref{Line Formats}.
@item --no-dereference
Act on symbolic links themselves instead of what they point to.
@item --old-group-format=@var{format}
Use @var{format} to output a group of lines taken from just the first
file in if-then-else format. @xref{Line Group Formats}.

74
src/diff.c
View File

@ -39,6 +39,7 @@
#include <timespec.h>
#include <version-etc.h>
#include <xalloc.h>
#include <xreadlink.h>
#include <binary-io.h>
/* The official name of this program (e.g., no `g' prefix). */
@ -120,6 +121,7 @@ enum
INHIBIT_HUNK_MERGE_OPTION,
LEFT_COLUMN_OPTION,
LINE_FORMAT_OPTION,
NO_DEREFERENCE_OPTION,
NO_IGNORE_FILE_NAME_CASE_OPTION,
NORMAL_OPTION,
SDIFF_MERGE_ASSIST_OPTION,
@ -188,6 +190,7 @@ static struct option const longopts[] =
{"new-file", 0, 0, 'N'},
{"new-group-format", 1, 0, NEW_GROUP_FORMAT_OPTION},
{"new-line-format", 1, 0, NEW_LINE_FORMAT_OPTION},
{"no-dereference", 0, 0, NO_DEREFERENCE_OPTION},
{"no-ignore-file-name-case", 0, 0, NO_IGNORE_FILE_NAME_CASE_OPTION},
{"normal", 0, 0, NORMAL_OPTION},
{"old-group-format", 1, 0, OLD_GROUP_FORMAT_OPTION},
@ -564,6 +567,10 @@ main (int argc, char **argv)
specify_value (&line_format[i], optarg, "--line-format");
break;
case NO_DEREFERENCE_OPTION:
no_dereference_symlinks = true;
break;
case NO_IGNORE_FILE_NAME_CASE_OPTION:
ignore_file_name_case = false;
break;
@ -872,6 +879,7 @@ static char const * const option_help_msgid[] = {
N_("-l, --paginate pass output through `pr' to paginate it"),
"",
N_("-r, --recursive recursively compare any subdirectories found"),
N_(" --no-dereference don't follow symbolic links"),
N_("-N, --new-file treat absent files as empty"),
N_(" --unidirectional-new-file treat absent first files as empty"),
N_(" --ignore-file-name-case ignore case when comparing file names"),
@ -1128,7 +1136,10 @@ compare_files (struct comparison const *parent,
set_mtime_to_now (&cmp.file[f].stat);
}
}
else if (stat (cmp.file[f].name, &cmp.file[f].stat) != 0)
else if ((no_dereference_symlinks
? lstat (cmp.file[f].name, &cmp.file[f].stat)
: stat (cmp.file[f].name, &cmp.file[f].stat))
!= 0)
cmp.file[f].desc = ERRNO_ENCODE (errno);
}
}
@ -1182,7 +1193,10 @@ compare_files (struct comparison const *parent,
if (STREQ (fnm, "-"))
fatal ("cannot compare `-' to a directory");
if (stat (filename, &cmp.file[dir_arg].stat) != 0)
if ((no_dereference_symlinks
? lstat (filename, &cmp.file[dir_arg].stat)
: stat (filename, &cmp.file[dir_arg].stat))
!= 0)
{
perror_with_name (filename);
status = EXIT_TROUBLE;
@ -1229,8 +1243,10 @@ compare_files (struct comparison const *parent,
}
else if ((DIR_P (0) | DIR_P (1))
|| (parent
&& (! S_ISREG (cmp.file[0].stat.st_mode)
|| ! S_ISREG (cmp.file[1].stat.st_mode))))
&& !((S_ISREG (cmp.file[0].stat.st_mode)
|| S_ISLNK (cmp.file[0].stat.st_mode))
&& (S_ISREG (cmp.file[1].stat.st_mode)
|| S_ISLNK (cmp.file[1].stat.st_mode)))))
{
if (cmp.file[0].desc == NONEXISTENT || cmp.file[1].desc == NONEXISTENT)
{
@ -1267,6 +1283,56 @@ compare_files (struct comparison const *parent,
file_label[1] ? file_label[1] : cmp.file[1].name,
file_type (&cmp.file[1].stat));
/* This is a difference. */
status = EXIT_FAILURE;
}
}
else if (S_ISLNK (cmp.file[0].stat.st_mode)
|| S_ISLNK (cmp.file[1].stat.st_mode))
{
/* We get here only if we use lstat(), not stat(). */
assert (no_dereference_symlinks);
if (S_ISLNK (cmp.file[0].stat.st_mode)
&& S_ISLNK (cmp.file[1].stat.st_mode))
{
/* Compare the values of the symbolic links. */
char *link_value[2] = { NULL, NULL };
for (f = 0; f < 2; f++)
{
link_value[f] = xreadlink (cmp.file[f].name);
if (link_value[f] == NULL)
{
perror_with_name (cmp.file[f].name);
status = EXIT_TROUBLE;
break;
}
}
if (status == EXIT_SUCCESS)
{
if (strcmp (link_value[0], link_value[1]) != 0)
{
message ("Symbolic links %s and %s differ\n",
cmp.file[0].name, cmp.file[1].name);
/* This is a difference. */
status = EXIT_FAILURE;
}
}
for (f = 0; f < 2; f++)
free (link_value[f]);
}
else
{
/* We have two files that are not to be compared, because
one of them is a symbolic link and the other one is not. */
message5 ("File %s is a %s while file %s is a %s\n",
file_label[0] ? file_label[0] : cmp.file[0].name,
file_type (&cmp.file[0].stat),
file_label[1] ? file_label[1] : cmp.file[1].name,
file_type (&cmp.file[1].stat));
/* This is a difference. */
status = EXIT_FAILURE;
}

4
src/diff.h
View File

@ -135,6 +135,10 @@ XTERN bool ignore_case;
/* Ignore differences in case of letters in file names. */
XTERN bool ignore_file_name_case;
/* Act on symbolic links themselves rather than on their target
(--no-dereference). */
XTERN bool no_dereference_symlinks;
/* File labels for `-c' output headers (--label). */
XTERN char *file_label[2];

1
tests/Makefile.am
View File

@ -8,6 +8,7 @@ TESTS = \
help-version \
function-line-vs-leading-space \
label-vs-func \
no-dereference \
no-newline-at-eof \
stdin

169
tests/no-dereference Normal file
View File

@ -0,0 +1,169 @@
#!/bin/sh
# Test the --no-dereference option.
. "${srcdir=.}/init.sh"; path_prepend_ ../src
echo 'Simple contents' > regular1
echo 'Sample contents' > regular2
echo 'Sample contents' > regular3
ln -s regular1 symlink1
ln -s regular1 symlink1bis
ln -s regular2 symlink2
ln -s regular3 symlink3
# Non-recursive comparisons.
# Test case 3: Compare regular file with regular file.
diff --no-dereference regular1 regular2 > out
test $? = 1 || fail=1
cat <<EOF > expected || framework_failure_
1c1
< Simple contents
---
> Sample contents
EOF
compare expected out || fail=1
# Test case 4: Compare regular file with symbolic link.
diff --no-dereference regular1 symlink1 > out
test $? = 1 || fail=1
cat <<EOF > expected || framework_failure_
File regular1 is a regular file while file symlink1 is a symbolic link
EOF
compare expected out || fail=1
# Test case 5: Compare symbolic link with regular file.
diff --no-dereference symlink1 regular1 > out
test $? = 1 || fail=1
cat <<EOF > expected || framework_failure_
File symlink1 is a symbolic link while file regular1 is a regular file
EOF
compare expected out || fail=1
# Test case 6: Compare symbolic links with same value.
diff --no-dereference symlink1 symlink1bis > out
test $? = 0 || fail=1
compare /dev/null out || fail=1
# Test case 7: Compare symbolic links with different value and different target
# contents.
diff --no-dereference symlink1 symlink2 > out
test $? = 1 || fail=1
cat <<EOF > expected || framework_failure_
Symbolic links symlink1 and symlink2 differ
EOF
compare expected out || fail=1
# Test case 8: Compare symbolic links with different value and same target
# contents.
diff --no-dereference symlink2 symlink3 > out
test $? = 1 || fail=1
cat <<EOF > expected || framework_failure_
Symbolic links symlink2 and symlink3 differ
EOF
compare expected out || fail=1
# Recursive comparisons.
# Test case 1: Compare symbolic link with nonexistent file.
mkdir subdir1a
mkdir subdir1b
ln -s nonexistent subdir1a/foo
ln -s ../regular1 subdir1a/bar
diff -r --no-dereference subdir1a subdir1b > out
test $? = 1 || fail=1
cat <<EOF > expected || framework_failure_
Only in subdir1a: bar
Only in subdir1a: foo
EOF
compare expected out || fail=1
# Test case 1: Compare nonexistent file with symbolic link.
mkdir subdir2a
mkdir subdir2b
ln -s nonexistent subdir2b/foo
ln -s ../regular1 subdir2b/bar
diff -r --no-dereference subdir2a subdir2b > out
test $? = 1 || fail=1
cat <<EOF > expected || framework_failure_
Only in subdir2b: bar
Only in subdir2b: foo
EOF
compare expected out || fail=1
# Test case 3: Compare regular file with regular file.
mkdir subdir3a
mkdir subdir3b
cp regular1 subdir3a/foo
cp regular2 subdir3b/foo
diff -r --no-dereference subdir3a subdir3b > out
test $? = 1 || fail=1
cat <<EOF > expected || framework_failure_
diff -r --no-dereference subdir3a/foo subdir3b/foo
1c1
< Simple contents
---
> Sample contents
EOF
compare expected out || fail=1
# Test case 4: Compare regular file with symbolic link.
mkdir subdir4a
mkdir subdir4b
cp regular1 subdir4a/foo
ln -s ../regular1 subdir4b/foo
diff -r --no-dereference subdir4a subdir4b > out
test $? = 1 || fail=1
cat <<EOF > expected || framework_failure_
File subdir4a/foo is a regular file while file subdir4b/foo is a symbolic link
EOF
compare expected out || fail=1
# Test case 5: Compare symbolic link with regular file.
mkdir subdir5a
mkdir subdir5b
ln -s ../regular1 subdir5a/foo
cp regular1 subdir5b/foo
diff -r --no-dereference subdir5a subdir5b > out
test $? = 1 || fail=1
cat <<EOF > expected || framework_failure_
File subdir5a/foo is a symbolic link while file subdir5b/foo is a regular file
EOF
compare expected out || fail=1
# Test case 6: Compare symbolic links with same value.
mkdir subdir6a
mkdir subdir6b
ln -s ../regular1 subdir6a/foo
ln -s ../regular1 subdir6b/foo
diff -r --no-dereference subdir6a subdir6b > out
test $? = 0 || fail=1
compare /dev/null out || fail=1
# Test case 7: Compare symbolic links with different value and different target
# contents.
mkdir subdir7a
mkdir subdir7b
ln -s ../regular1 subdir7a/foo
ln -s ../regular2 subdir7b/foo
diff -r --no-dereference subdir7a subdir7b > out
test $? = 1 || fail=1
cat <<EOF > expected || framework_failure_
Symbolic links subdir7a/foo and subdir7b/foo differ
EOF
compare expected out || fail=1
# Test case 8: Compare symbolic links with different value and same target
# contents.
mkdir subdir8a
mkdir subdir8b
ln -s ../regular2 subdir8a/foo
ln -s ../regular3 subdir8b/foo
diff -r --no-dereference subdir8a subdir8b > out
test $? = 1 || fail=1
cat <<EOF > expected || framework_failure_
Symbolic links subdir8a/foo and subdir8b/foo differ
EOF
compare expected out || fail=1
Exit $fail