> The attached program gives EROFS at fgetpos() when called with FILE being
> on a read-only filesystem. I had no debug symbols installed, so I didn't
> track it down any further yet. From reading the stdio/fgetpos.c and ftell.c,
> I couldn't see how the filesystem was accessed even.
>
>
Hello Marcus,
Stepped your program through gdb, hope this is of some use.
Running this as a user damages somthing. At the end of the trace, when gdb has
not replied to a step; the machine is nearly frozen. If you try to do too many
things in other screens you lose control.
Using another screen, I switched to su, did a ps aux, then rebooted. These were
the processes running after the gdb freeze:
Chris
Script started on Sat Apr 15 19:09:11 2000
cal@hurd:~$ gdb marcus
GNU gdb 19990928
Copyright 1998 Free Software Foundation, Inc.
GDB is free software, covered by the GNU General Public License, and you are
welcome to change it and/or distribute copies of it under certain conditions.
Type "show copying" to see the conditions.
There is absolutely no warranty for GDB. Type "show warranty" for details.
This GDB was configured as "i386-unknown-gnu0.2"...
(gdb) list
1 #include <stdio.h>
2 #include <string.h>
3 #include <errno.h>
4
5 main(int argc, char *argv[])
6 {
7 FILE *f;
8 fpos_t fpos;
9
10 if (argc != 2) {
(gdb) b 10
Breakpoint 1 at 0x8048646: file marcus.c, line 10.
(gdb) run /Source/Marcus
Starting program: /home/cal/marcus /Source/Marcus
[Switching to thread 97.3]
[Switching to thread 97.4]
Breakpoint 1, main (argc=2, argv=0x1019ba0) at marcus.c:10
10 if (argc != 2) {
(gdb) info shared
>From To Syms Read Shared Object Library
0x0101f000 0x0114ec64 Yes /lib/debug/libc.so.0.2
0x00001000 0x000185d8 Yes /lib/ld.so
0x0114f000 0x0115f340 Yes /lib/debug/libmachuser.so.1
0x01161000 0x0117e284 Yes /lib/debug/libhurduser.so.0.0
(gdb) list
5 main(int argc, char *argv[])
6 {
7 FILE *f;
8 fpos_t fpos;
9
10 if (argc != 2) {
11 printf("Usage: %s FILE\n", argv[0]);
12 return;
13 }
14 f = fopen(argv[1], "r");
(gdb) list
15 if (!f) {
16 printf ("fopen: %s\n", strerror(errno));
17 return;
18 }
19 if (0 != fgetpos(f, &fpos)) {
20 printf ("fgetpos: %s\n", strerror(errno));
21 }
22 fclose(f);
23 }
(gdb) b 19
Breakpoint 2 at 0x80486b5: file marcus.c, line 19.
(gdb) cont
Continuing.
Breakpoint 2, main (argc=2, argv=0x1019ba0) at marcus.c:19
19 if (0 != fgetpos(f, &fpos)) {
(gdb) step
fgetpos (stream=0x80499d0, pos=0x1019b34) at fgetpos.c:31
fgetpos.c: Read-only file system.
(gdb) step
fgetpos.c: Read-only file system.
(gdb) step
ftell (stream=0x80499d0) at ftell.c:28
ftell.c: Read-only file system.
(gdb) step
ftell.c: Read-only file system.
(gdb) step
ftell.c: Read-only file system.
(gdb) step
__stdio_check_offset (stream=0x80499d0) at internals.c:101
internals.c: Read-only file system.
(gdb) step
init_stream (fp=0x80499d0) at internals.c:55
internals.c: Read-only file system.
(gdb) step
__stdio_check_funcs (fp=0x80499d0) at internals.c:37
internals.c: Read-only file system.
(gdb) bt
#0 __stdio_check_funcs (fp=0x80499d0) at internals.c:37
#1 0x10918f1 in init_stream (fp=0x80499d0) at internals.c:55
#2 0x10919fc in __stdio_check_offset (stream=0x80499d0) at internals.c:101
#3 0x108ec21 in ftell (stream=0x80499d0) at ftell.c:36
#4 0x108ed1e in fgetpos (stream=0x80499d0, pos=0x1019b34) at fgetpos.c:37
#5 0x80486c5 in main (argc=2, argv=0x1019ba0) at marcus.c:19
(gdb) btstep
internals.c: Read-only file system.
(gdb) step
internals.c: Read-only file system.
(gdb) step
__stdio_init_stream (stream=0x80499d0) at ../sysdeps/mach/hurd/stdio_init.c:38
../sysdeps/mach/hurd/stdio_init.c: Read-only file system.
(gdb) bt
#0 __stdio_init_stream (stream=0x80499d0)
at ../sysdeps/mach/hurd/stdio_init.c:38
#1 0x10918c1 in __stdio_check_funcs (fp=0x80499d0) at internals.c:39
#2 0x10918f1 in init_stream (fp=0x80499d0) at internals.c:55
#3 0x10919fc in __stdio_check_offset (stream=0x80499d0) at internals.c:101
#4 0x108ec21 in ftell (stream=0x80499d0) at ftell.c:36
#5 0x108ed1e in fgetpos (stream=0x80499d0, pos=0x1019b34) at fgetpos.c:37
#6 0x80486c5 in main (argc=2, argv=0x1019ba0) at marcus.c:19
(gdb) btstep
../sysdeps/mach/hurd/stdio_init.c: Read-only file system.
(gdb) step
../hurd/hurd/threadvar.h: Read-only file system.
(gdb) bt
#0 __stdio_init_stream (stream=0x80499d0) at ../hurd/hurd/threadvar.h:81
#1 0x10918c1 in __stdio_check_funcs (fp=0x80499d0) at internals.c:39
#2 0x10918f1 in init_stream (fp=0x80499d0) at internals.c:55
#3 0x10919fc in __stdio_check_offset (stream=0x80499d0) at internals.c:101
#4 0x108ec21 in ftell (stream=0x80499d0) at ftell.c:36
#5 0x108ed1e in fgetpos (stream=0x80499d0, pos=0x1019b34) at fgetpos.c:37
#6 0x80486c5 in main (argc=2, argv=0x1019ba0) at marcus.c:19
(gdb) btstep
../hurd/hurd/threadvar.h: Read-only file system.
(gdb) step
../sysdeps/mach/i386/machine-lock.h: Read-only file system.
(gdb) step
../hurd/hurd/signal.h: Read-only file system.
(gdb) bt
#0 __stdio_init_stream (stream=0x80499d0) at ../hurd/hurd/signal.h:189
#1 0x10918c1 in __stdio_check_funcs (fp=0x80499d0) at internals.c:39
#2 0x10918f1 in init_stream (fp=0x80499d0) at internals.c:55
#3 0x10919fc in __stdio_check_offset (stream=0x80499d0) at internals.c:101
#4 0x108ec21 in ftell (stream=0x80499d0) at ftell.c:36
#5 0x108ed1e in fgetpos (stream=0x80499d0, pos=0x1019b34) at fgetpos.c:37
#6 0x80486c5 in main (argc=2, argv=0x1019ba0) at marcus.c:19
(gdb) btstep
../hurd/hurd/signal.h: Read-only file system.
(gdb) step
../hurd/hurd/signal.h: Read-only file system.
(gdb) bt
#0 __stdio_init_stream (stream=0x80499d0) at ../hurd/hurd/signal.h:190
#1 0x10918c1 in __stdio_check_funcs (fp=0x80499d0) at internals.c:39
#2 0x10918f1 in init_stream (fp=0x80499d0) at internals.c:55
#3 0x10919fc in __stdio_check_offset (stream=0x80499d0) at internals.c:101
#4 0x108ec21 in ftell (stream=0x80499d0) at ftell.c:36
#5 0x108ed1e in fgetpos (stream=0x80499d0, pos=0x1019b34) at fgetpos.c:37
#6 0x80486c5 in main (argc=2, argv=0x1019ba0) at marcus.c:19
(gdb) btstep
../sysdeps/mach/hurd/stdio_init.c: Read-only file system.
(gdb) bt
#0 __stdio_init_stream (stream=0x80499d0)
at ../sysdeps/mach/hurd/stdio_init.c:43
#1 0x10918c1 in __stdio_check_funcs (fp=0x80499d0) at internals.c:39
#2 0x10918f1 in init_stream (fp=0x80499d0) at internals.c:55
#3 0x10919fc in __stdio_check_offset (stream=0x80499d0) at internals.c:101
#4 0x108ec21 in ftell (stream=0x80499d0) at ftell.c:36
#5 0x108ed1e in fgetpos (stream=0x80499d0, pos=0x1019b34) at fgetpos.c:37
#6 0x80486c5 in main (argc=2, argv=0x1019ba0) at marcus.c:19
(gdb) btstep
../hurd/hurd/port.h: Read-only file system.
(gdb) step
../mach/lock-intern.h: Read-only file system.
(gdb) bt
#0 __stdio_init_stream (stream=0x80499d0) at ../mach/lock-intern.h:48
#1 0x10918c1 in __stdio_check_funcs (fp=0x80499d0) at internals.c:39
#2 0x10918f1 in init_stream (fp=0x80499d0) at internals.c:55
#3 0x10919fc in __stdio_check_offset (stream=0x80499d0) at internals.c:101
#4 0x108ec21 in ftell (stream=0x80499d0) at ftell.c:36
#5 0x108ed1e in fgetpos (stream=0x80499d0, pos=0x1019b34) at fgetpos.c:37
#6 0x80486c5 in main (argc=2, argv=0x1019ba0) at marcus.c:19
(gdb) btstep
../sysdeps/mach/i386/machine-lock.h: Read-only file system.
(gdb) step
../hurd/hurd/signal.h: Read-only file system.
(gdb) step
../hurd/hurd/signal.h: Read-only file system.
(gdb) step
../hurd/hurd/threadvar.h: Read-only file system.
(gdb) bt
#0 __stdio_init_stream (stream=0x80499d0) at ../hurd/hurd/threadvar.h:81
#1 0x10918c1 in __stdio_check_funcs (fp=0x80499d0) at internals.c:39
#2 0x10918f1 in init_stream (fp=0x80499d0) at internals.c:55
#3 0x10919fc in __stdio_check_offset (stream=0x80499d0) at internals.c:101
#4 0x108ec21 in ftell (stream=0x80499d0) at ftell.c:36
#5 0x108ed1e in fgetpos (stream=0x80499d0, pos=0x1019b34) at fgetpos.c:37
#6 0x80486c5 in main (argc=2, argv=0x1019ba0) at marcus.c:19
(gdb) btstep
../hurd/hurd/threadvar.h: Read-only file system.
(gdb) step
../sysdeps/mach/hurd/stdio_init.c: Read-only file system.
(gdb) bt
#0 __stdio_init_stream (stream=0x80499d0)
at ../sysdeps/mach/hurd/stdio_init.c:43
#1 0x10918c1 in __stdio_check_funcs (fp=0x80499d0) at internals.c:39
#2 0x10918f1 in init_stream (fp=0x80499d0) at internals.c:55
#3 0x10919fc in __stdio_check_offset (stream=0x80499d0) at internals.c:101
#4 0x108ec21 in ftell (stream=0x80499d0) at ftell.c:36
#5 0x108ed1e in fgetpos (stream=0x80499d0, pos=0x1019b34) at fgetpos.c:37
#6 0x80486c5 in main (argc=2, argv=0x1019ba0) at marcus.c:19
(gdb) btstep
__io_stat (stat_object=91, stat_info=0x101999c)
at /Source/glibc-2.1.3/i386-gnu/obj/hurd/RPC_io_stat.c:67
/Source/glibc-2.1.3/i386-gnu/obj/hurd/RPC_io_stat.c: Read-only file system.
(gdb) bt
#0 __io_stat (stat_object=91, stat_info=0x101999c)
at /Source/glibc-2.1.3/i386-gnu/obj/hurd/RPC_io_stat.c:67
#1 0x1093e5c in __stdio_init_stream (stream=0x80499d0)
at ../sysdeps/mach/hurd/stdio_init.c:43
#2 0x10918c1 in __stdio_check_funcs (fp=0x80499d0) at internals.c:39
#3 0x10918f1 in init_stream (fp=0x80499d0) at internals.c:55
#4 0x10919fc in __stdio_check_offset (stream=0x80499d0) at internals.c:101
#5 0x108ec21 in ftell (stream=0x80499d0) at ftell.c:36
#6 0x108ed1e in fgetpos (stream=0x80499d0, pos=0x1019b34) at fgetpos.c:37
#7 0x80486c5 in main (argc=2, argv=0x1019ba0) at marcus.c:19
(gdb) btstep
/Source/glibc-2.1.3/i386-gnu/obj/hurd/RPC_io_stat.c: Read-only file system.
(gdb) bt
#0 __io_stat (stat_object=91, stat_info=0x101999c)
at /Source/glibc-2.1.3/i386-gnu/obj/hurd/RPC_io_stat.c:95
#1 0x1093e5c in __stdio_init_stream (stream=0x80499d0)
at ../sysdeps/mach/hurd/stdio_init.c:43
#2 0x10918c1 in __stdio_check_funcs (fp=0x80499d0) at internals.c:39
#3 0x10918f1 in init_stream (fp=0x80499d0) at internals.c:55
#4 0x10919fc in __stdio_check_offset (stream=0x80499d0) at internals.c:101
#5 0x108ec21 in ftell (stream=0x80499d0) at ftell.c:36
#6 0x108ed1e in fgetpos (stream=0x80499d0, pos=0x1019b34) at fgetpos.c:37
#7 0x80486c5 in main (argc=2, argv=0x1019ba0) at marcus.c:19
(gdb) btstep
/Source/glibc-2.1.3/i386-gnu/obj/hurd/RPC_io_stat.c: Read-only file system.
(gdb) bt
#0 __io_stat (stat_object=91, stat_info=0x101999c)
at /Source/glibc-2.1.3/i386-gnu/obj/hurd/RPC_io_stat.c:98
#1 0x1093e5c in __stdio_init_stream (stream=0x80499d0)
at ../sysdeps/mach/hurd/stdio_init.c:43
#2 0x10918c1 in __stdio_check_funcs (fp=0x80499d0) at internals.c:39
#3 0x10918f1 in init_stream (fp=0x80499d0) at internals.c:55
#4 0x10919fc in __stdio_check_offset (stream=0x80499d0) at internals.c:101
#5 0x108ec21 in ftell (stream=0x80499d0) at ftell.c:36
#6 0x108ed1e in fgetpos (stream=0x80499d0, pos=0x1019b34) at fgetpos.c:37
#7 0x80486c5 in main (argc=2, argv=0x1019ba0) at marcus.c:19
(gdb) btstep
/Source/glibc-2.1.3/i386-gnu/obj/hurd/RPC_io_stat.c: Read-only file system.
(gdb) step
USER PID %CPU %MEM SZ RSS TT STAT START TIME COMMAND
root 106 1.0 0.4 145M 796K p2 S 7:14PM 0:00.03 ps -aux
root 62 0.4 0.5 130M 932K - So 7:04PM 0:01.04 /hurd/term /dev/p
root 4 0.4 1.6 1.09G 3.08M - So 7:03PM 0:05.61 /hurd/ext2fs.stat
root 66 0.2 0.5 130M 920K - So 7:04PM 0:01.24 /hurd/term /dev/p
root 8 0.2 0.5 130M 988K - So 7:03PM 0:10.49 /hurd/term /dev/c
root 0 0.0 0.5 130M 1008K ? R<mo 7:03PM 0:01.77 /hurd/proc
- 2 0.0 2.4 218M 4.64M ? D<p 7:03PM 0:00.03 /boot/gnumach roo
- 3 0.0 0.5 128M 1.03M ? Sp 7:03PM 0:00.18 ?
root 5 0.0 0.5 130M 992K - So 7:03PM 0:00.44 /hurd/exec
root 6 0.0 0.4 129M 776K - So 7:03PM 0:00.43 /hurd/auth
root 12 0.0 0.4 130M 880K - So 7:03PM 0:00.02 /hurd/storeio hd0
root 16 0.0 0.4 129M 832K - So 7:03PM 0:00.06 /hurd/null
root 17 0.0 0.5 130M 888K - So 7:03PM 0:00.02 /hurd/storeio hd1
root 21 0.0 0.5 130M 892K - So 7:03PM 0:00.03 /hurd/storeio hd1
root 22 0.0 0.5 130M 888K - So 7:03PM 0:00.04 /hurd/storeio hd1
root 23 0.0 0.5 130M 892K - So 7:03PM 0:00.06 /hurd/storeio hd0
root 41 0.0 0.4 130M 860K - So 7:03PM 0:00.04 /hurd/pflocal
root 42 0.0 0.8 131M 1.62M - So 7:03PM 0:00.14 /hurd/pfinet
root 43 0.0 0.5 130M 888K - So 7:03PM 0:00.04 /hurd/storeio tim
root 44 0.0 0.6 130M 1.13M - So 7:03PM 0:00.07 /hurd/password
root 46 0.0 0.7 1.1G 1.4M - So 7:03PM 0:00.35 /hurd/ext2fs /dev
root 56 0.0 0.5 146M 1.03M co S 7:04PM 0:00.05 screen
cal 59 0.0 0.5 130M 888K - So 7:04PM 0:01.12 /hurd/fifo
root 60 0.0 0.5 130M 956K - So 7:04PM 0:00.90 /hurd/term /dev/p
root 64 0.0 0.5 130M 952K - So 7:04PM 0:01.04 /hurd/term /dev/p
root 69 0.0 0.5 130M 924K - So 7:05PM 0:00.39 /hurd/term /dev/p
root 76 0.0 0.8 1.09G 1.53M - So 7:06PM 0:00.11 /hurd/ext2fs -r /
root 93 0.0 0.4 145M 836K p0 S 7:09PM 0:00.03 script screen2
root 94 0.0 0.3 145M 660K p0 Sf 7:09PM 0:00.06 script screen2
root 96 0.0 4.8 148M 9.15M p4 Sw 7:09PM 0:07.20 gdb marcus
cal 97 0.0 0.3 145M 588K ? Tx 7:09PM 0:00.86 /home/cal/marcus
root 102 0.0 0.4 129M 748K - So 7:13PM 0:00.02 /hurd/magic tty
