l4-hackers

Download

l4-hackers@os.inf.tu-dresden.de

July 2010

1 participants
1 discussions

l4vfs and stdin/stdout handles
by Valery V. Sedletski 02 Jul '10

02 Jul '10

Hi all. I am trying to make a test using l4vfs libc backends so the three predefined file descriptors 0, 1, 2 work for stdin, stdout and stderr correspondingly. It appears that these file descriptors are already predefined for some purpose: when I am trying to open files like this: // open initial file descriptors // stdin fd = open("/vc/vc0", O_RDONLY); LOG("stdin: fd=%d, errno=%d", fd, errno); // strout fd = open("/vc/vc0", O_WRONLY); LOG("stdout: fd=%d, errno=%d", fd, errno); // stderr fd = open("/vc/vc0", O_WRONLY); LOG("stderr: fd=%d, errno=%d", fd, errno); -- like in term_con_test example for term_con server, the 3, 4, 5 descriptors are returned from open(). If I not use term_con at all, and not open vc0 three times as above, read(0, ....); and write(1,....); works but strangely. For example, read() returns immediately with no error and returns a single symbol (EOF, I think). But as I tested in Linux and OS/2 operating systems, when stdin is a console, read(0,...); must block until '\n' is returned (user pressed an Enter key). So, it seems that the file descriptors 0, 1, 2 are reserved, but they are not working as expected. Maybe, my setup is incorrect or something is not yet implemented? I have a menu.lst entry like this: title The "Hello, world!" program kernel $(A)/bootstrap -serial modaddr 0x02000000 module $(B)/fiasco $(FIASCOARGS) module $(B)/sigma0 module $(B)/roottask \ task modname 'simple_file_server' attached 6 modules module $(B)/log module $(B)/names module $(B)/dm_phys module $(B)/l4io module $(B)/rtc module $(B)/l4con module $(B)/simple_ts -t 300 module $(B)/name_server module $(B)/term_con module $(B)/simple_file_server -v 14 module $(B)/os2/config.sys module $(B)/os2/mini33.exe module $(B)/os2/minicmd.exe module $(B)/os2/msg.dll module $(B)/os2/doscalls.dll module $(B)/os2/sub32.dll module $(B)/fstab \ -c /file \ -c /file/system -v 14 -b / -m /file/system \ -c /vc -v 132 -b / -m /vc module $(B)/os2/os2server -d c: -m /file/system vbeset $(VBE_MODE) I needed to relink a term_con server to an address 0x01450000 instead of the default one of 0x01400000 because the latter was the same as with simple_ts server (0x01400000 too). I was not able to use loader server to load at other address because I needed to launch two l4vfs servers, term_con and simple_file_server where simple_file_server serves all files through fprov_proxy file provider (I don't want to use an extra bmodfs server to serve files for loader -- it would be an ugly decision, I think). The 'os2server' server uses the files that were served by simple_file_server and it tries to use l4vfs servers for reading from stdin. My makefile looks like this: PKGDIR ?= ../.. L4DIR ?= $(PKGDIR)/../.. TARGET = os2server # the default relocation address. This may be superseded by a STATIC file. DEFAULT_RELOC = 0x01800000 # list your .c files here # os2server.c SRC_C = main.c utility.c io.c MountReg.c globals.c native_dynlink.c l4_alloc_mem.c \ Shared/token.c \ Shared/modmgr.c \ Shared/ixfmgr.c \ Shared/ixfmgr_lx.c \ Shared/ixfmgr_lx_load.c \ Shared/ixfmgr_ne.c \ Shared/ixfmgr_lx_fixuplx.c \ Shared/ixfmgr_lx_loadobjlx.c \ Shared/ixfmgr_lx_modlx.c \ Shared/ixfmgr_lx_execlx.c \ Shared/ixfmgr_lx_debuglx.c \ Shared/memmgr.c \ Shared/api/apistub.c \ Shared/cfgparser.c \ Shared/processmgr.c #Shared/ow_dlfcn.c \ # if your server implements the server side of an idl defined in an idl-file # of your package, list the idl file name(s) here (no path needed) SERVERIDL = os2server.idl # list additional library paths and libraries here LIBS = -los2server -lparsecmdline -lthread -lcon -lcontxt -lconstream-server CFLAGS = -I$(PKGDIR)/include MODE=l4env_base include $(L4DIR)/mk/prog.mk Maybe some libs are interfere with l4vfs ones or something like this? I suspect the l4con server libs interfere with l4vfs libs. For example, l4con has its own getchar() implementation but in uCLibc this function is implemented through l4vfs backends. When I am trying to use getchar() or scanf() functions, I see that read() function is called behind the scenes, and it don't get blocked until Enter is pressed. So, any help is appreciated. WBR, valery

2 5