| Message ID | 7d651d9d-08c9-4356-9cfa-1673449a7af3@charter.net |
|---|---|
| State | New |
| Headers | show |
| Series | [libgfortran] PR88776 Namelist read from stdin: loss of data | expand |
On 1/12/19 2:35 PM, Jerry DeLisle wrote: > Hi all, > > As stated in the PR, the problem turns out to be an ungraceful return > after an error. Most namelist errors go through nml_err_ret, The one I > am removing did not and in the unique case of UNIT=5 after the error it > falls through and hits some code which modifies pointers to the namelist > data structures. > > This patch fixes it. > > Regression tested on x86-64 and manually tested with a redirection to > stdin. (cat somefile | ./a.out ) > > I plan to commit today as simple along with a new testcase. > > Regards. > > Jerry > > 2019-01-12 Jerry DeLisle <jvdelisle@gcc.gnu.org> > > PR libfortran/88776 > * io/list_read.c (namelist_read): Use nml_err_ret path on > read error, not based on stdin_unit. Committed. While doing extra testing on the test case for this PR, I noticed a memory leak with valgrind. The attached patch fixes this. The problem is when opening a file with a preconnected unit, the previously initialized format buffer (fbuf) in the preconnected unit structure gets abandoned (pointer overwritten by the new fbuf), and a new one allocated later in the code path. I will commit this additional patch and the test case as simple and obvious. Regression tested on x86_64. Valgrind clean. Regards, Jerry 2019-01-13 Jerry DeLisle <jvdelisle@gcc.gnu.org> PR libfortran/88776 * io/open.c (newunit): Free format buffer if the unit specified is for stdin, stdout, or stderr. 2019-01-13 Jerry DeLisle <jvdelisle@gcc.gnu.org> PR libfortran/88776 * gfortran.dg/namelist_96.f90: New test. diff --git a/libgfortran/io/open.c b/libgfortran/io/open.c index 97fb17c7424..b48afabf7a3 100644 --- a/libgfortran/io/open.c +++ b/libgfortran/io/open.c @@ -530,6 +530,14 @@ new_unit (st_parameter_open *opp, gfc_unit *u, unit_flags *flags) if (u2 != NULL) unlock_unit (u2); + /* If the unit specified is preconnected with a file specified to be open, + then clear the format buffer. */ + if ((opp->common.unit == options.stdin_unit || + opp->common.unit == options.stdout_unit || + opp->common.unit == options.stderr_unit) + && (opp->common.flags & IOPARM_OPEN_HAS_FILE) != 0) + fbuf_destroy (u); + /* Open file. */ s = open_external (opp, flags); ! ( dg-do run } program pr88776 implicit none character(*), parameter :: file = "pr88776.dat" type t_chan integer :: ichan = -1 character(len=8) :: flag = '' integer :: band = -1 end type t_chan type(t_chan) :: chan namelist /NML/ chan open (11,file=file) write(11,'(a)') trim("&nml chan = 1 '#1 ' 10 /") write(11,'(a)') trim("&nml chan = 2 '#2 ' 42.36/") write(11,'(a)') trim("&nml chan = 3 '#3 ' 30 /") close(11) call read (unit=10) ! No problem call read (unit=5) ! problem, now fixed open (11,file=file) close (11, status="delete") contains subroutine read (unit) integer, intent(in) :: unit integer :: stat open (unit, file=file, action="read") chan = t_chan(-1,'',-1) stat = 0 read (unit, nml=NML, iostat=stat) if (stat /= 0) stop 1 chan = t_chan(-1,'',-1) read (unit, nml=NML, iostat=stat) if (stat == 0) stop 2 if (chan% ichan /= 2) then stop 3 end if close (unit) end subroutine read end program pr88776
diff --git a/libgfortran/io/list_read.c b/libgfortran/io/list_read.c index 4a7ccb3ddd5..d9af255a034 100644 --- a/libgfortran/io/list_read.c +++ b/libgfortran/io/list_read.c @@ -3614,11 +3614,7 @@ find_nml_name: while (!dtp->u.p.input_complete) { if (!nml_get_obj_data (dtp, &prev_nl, nml_err_msg, sizeof nml_err_msg)) - { - if (dtp->u.p.current_unit->unit_number != options.stdin_unit) - goto nml_err_ret; - generate_error (&dtp->common, LIBERROR_READ_VALUE, nml_err_msg); - } + goto nml_err_ret; /* Reset the previous namelist pointer if we know we are not going to be doing multiple reads within a single namelist object. */