wc: don't miscount /sys and similar file systems

Fix similar problems in head, od, split, tac, and tail.
Reported by George Shuklin in: http://bugs.gnu.org/18621
* NEWS: Document this.
* src/head.c (elseek): Move up.
(elide_tail_bytes_pipe, elide_tail_lines_pipe): New arg
CURRENT_POS.  All uses changed.
(elide_tail_bytes_file, elide_tail_lines_file):
New arg ST and remove arg SIZE.  All uses changed.
* src/head.c (elide_tail_bytes_file):
* src/od.c (skip): Avoid optimization for /sys files, where
st_size is bogus and st_size == st_blksize.
Don't report error at EOF when not optimizing.
* src/head.c, src/od.c, src/tail.c: Include "stat-size.h".
* src/split.c (input_file_size): New function.
(bytes_split, lines_chunk_split, bytes_chunk_extract): New arg
INITIAL_READ.  All uses changed. Use it to double-check st_size.
* src/tac.c (tac_seekable): New arg FILE_POS.  All uses changed.
(copy_to_temp): Return size of temp file.  All uses changed.
* src/tac.c (tac_seekable):
* src/tail.c (tail_bytes):
* src/wc.c (wc):
Don't trust st_size; double-check by reading.
* src/wc.c (wc): New arg CURRENT_POS.  All uses changed.
* tests/local.mk (all_tests): Add tests/misc/wc-proc.sh,
tests/misc/od-j.sh, tests/tail-2/tail-c.sh.
* tests/misc/head-c.sh:
* tests/misc/tac-2-nonseekable.sh:
* tests/split/b-chunk.sh:
Add tests for problems with /proc and /sys files.
* tests/misc/od-j.sh, tests/misc/wc-proc.sh, tests/tail-2/tail-c.sh:
New files.

1 files changed, 24 insertions, 15 deletions

diff --git a/tests/split/b-chunk.sh b/tests/split/b-chunk.sh
index 86f95a057..fefa0900d 100755
--- a/tests/split/b-chunk.sh
+++ b/tests/split/b-chunk.sh
@@ -31,20 +31,29 @@ stat x?? 2>/dev/null && fail=1
 
 printf '1\n2\n3\n4\n5\n' > in || framework_failure_
 
-split -n 3 in > out || fail=1
-split -n 1/3 in > b1 || fail=1
-split -n 2/3 in > b2 || fail=1
-split -n 3/3 in > b3 || fail=1
-printf '1\n2' > exp-1
-printf '\n3\n' > exp-2
-printf '4\n5\n' > exp-3
-
-compare exp-1 xaa || fail=1
-compare exp-2 xab || fail=1
-compare exp-3 xac || fail=1
-compare exp-1 b1 || fail=1
-compare exp-2 b2 || fail=1
-compare exp-3 b3 || fail=1
-test -f xad && fail=1
+for file in in /proc/version /sys/kernel/profiling; do
+  split -n 3 $file > out || fail=1
+  split -n 1/3 $file > b1 || fail=1
+  split -n 2/3 $file > b2 || fail=1
+  split -n 3/3 $file > b3 || fail=1
+
+  case $file in
+    in)
+      printf '1\n2' > exp-1
+      printf '\n3\n' > exp-2
+      printf '4\n5\n' > exp-3
+
+      compare exp-1 xaa || fail=1
+      compare exp-2 xab || fail=1
+      compare exp-3 xac || fail=1
+      ;;
+  esac
+
+  compare xaa b1 || fail=1
+  compare xab b2 || fail=1
+  compare xac b3 || fail=1
+  cat xaa xab xac | compare - $file || fail=1
+  test -f xad && fail=1
+done
 
 Exit $fail