Hello,
A somewhat exotic test failure:
On Debian/kFreeBSD 'tests/df/skip-duplicates' fails with 'df' segfaulting like
so:
...
./tests/df/skip-duplicates.sh: line 113: 7741 Segmentation fault
LD_PRELOAD=./k.so df
...
The flow is:
1. the "k.so" file (inlined C code in 'tests/df/skip-duplicates.sh') returns
'struct mntent' in which '.mnt_opts' is NULL (not just empty string)
2. read_file_system_list() calls dev_from_mount_options(mnt->mnt_opts) .
3. in dev_from_mount_options() "__linux__" is not defined (using FreeBSD
kernel v9).
4. strstr() is called with 'mount_options==NULL'.
5. libc segfaults.
The direct culprit is 'dev_from_mount_options' in gnulib's mountlist.c, which
has:
static dev_t
dev_from_mount_options (char const *mount_options)
{
/* GNU/Linux allows file system implementations to define their own
meaning for "dev=" mount options, so don't trust the meaning
here. */
# ifndef __linux__
static char const dev_pattern[] = ",dev=";
char const *devopt = strstr (mount_options, dev_pattern);
...
Using gdb, the stack-trace is:
$ gdb ../src/df
(gdb) set environment LD_PRELOAD=./k.so
(gdb) start
Program received signal SIGSEGV, Segmentation fault.
0x0000000800abcc04 in strstr () from /lib/x86_64-kfreebsd-gnu/libc.so.0.1
(gdb) bt
#0 0x0000000800abcc04 in strstr () from
/lib/x86_64-kfreebsd-gnu/libc.so.0.1
#1 0x000000000040f7ed in dev_from_mount_options (mount_options=0x0) at
lib/mountlist.c:363
#2 0x000000000040fb6c in read_file_system_list (need_fs_type=false) at
lib/mountlist.c:449
#3 0x0000000000405751 in main (argc=1, argv=0x7fffffffd648) at
src/df.c:1647
I'm not sure what is the correct,clean fix, attached are two options (one fixes
the test, one avoids the call in lib/mountlist.c).
Regards,
- assaf
P.S.
On FReeBSD-10.1 the test is skipped:
skip-duplicates.sh: skipped test: $CC -shared ... failed to build a shared
lib
SKIP: tests/df/skip-duplicates.sh
--- tests/df/skip-duplicates.sh.bad 2014-07-13 18:09:52.000000000 -0400
+++ tests/df/skip-duplicates.sh 2015-03-26 20:24:22.000000000 -0400
@@ -56,13 +56,13 @@ struct mntent *getmntent (FILE *fp)
}
static struct mntent mntents[] = {
- {.mnt_fsname="/short", .mnt_dir="/invalid/mount/dir"},
- {.mnt_fsname="fsname", .mnt_dir="/",},
- {.mnt_fsname="/fsname", .mnt_dir="/."},
- {.mnt_fsname="/fsname", .mnt_dir="/"},
- {.mnt_fsname="virtfs", .mnt_dir="/NONROOT", .mnt_type="fstype1"},
- {.mnt_fsname="virtfs2", .mnt_dir="/NONROOT", .mnt_type="fstype2"},
- {.mnt_fsname="netns", .mnt_dir="net:[1234567]"},
+ {.mnt_fsname="/short", .mnt_dir="/invalid/mount/dir", .mnt_opts=""},
+ {.mnt_fsname="fsname", .mnt_dir="/", .mnt_opts=""},
+ {.mnt_fsname="/fsname", .mnt_dir="/.", .mnt_opts=""},
+ {.mnt_fsname="/fsname", .mnt_dir="/", .mnt_opts=""},
+ {.mnt_fsname="virtfs", .mnt_dir="/NONROOT", .mnt_type="fstype1", .mnt_opts=""},
+ {.mnt_fsname="virtfs2", .mnt_dir="/NONROOT", .mnt_type="fstype2", .mnt_opts=""},
+ {.mnt_fsname="netns", .mnt_dir="net:[1234567]", .mnt_opts=""},
};
if (done == 1)
--- lib/mountlist.c.bad 2015-03-26 20:30:05.000000000 -0400
+++ lib/mountlist.c 2015-03-26 20:36:54.000000000 -0400
@@ -360,7 +360,9 @@ dev_from_mount_options (char const *moun
# ifndef __linux__
static char const dev_pattern[] = ",dev=";
- char const *devopt = strstr (mount_options, dev_pattern);
+ char const *devopt = (mount_options)?
+ strstr (mount_options, dev_pattern):
+ NULL;
if (devopt)
{
