为用户模式Linux编译程序

Question

I've just implemented a "pseudo" device driver and want to test it. What can I do as a test is just:

echo "something"> /dev/mydev
cat /dev/mydev

My driver supports more advanced functionality and I implemented a test program to test these functionaries. However I'm not able to run it on UML (Error: Floating point exception). I believe there is a "special" way of compiling user programs for UML?

Could you please give a starting point for this? How should I compile the test program?

ps Testing program is very simple and above error is not caused by the bug in the program. pps For compiling the module I had ready Makefile, so it was easy :)

Thanks in advance.

EDIT: Both host and UML kernels are of same version 2.6.35

EDIT: I believe I need to show kernel source directory, plus some compiler options, also something like ARCH=um?

EDIT: Currently I'm compiling without any options. gcc test.c. Even the "Hello world" program is not working on the UML. Maybe i've to change something on UML compilation?

Answer 1

The solution for the problem is found (thanks to my classmates and professor):

the glibc versions of the compile environment should match with UML. So compiling --static option solves the problem.

Answer 2

If you want to read/write from/to your device, you have to implement, and then use on your program, at least the system calls open() , read() , write() and close() , like any other device on you Linux. For the example you gave, your program would be something like this (syntax might contain some errors):

char* string = "something";
char* result = (char*)malloc(sizeof(char) * strlen(string) + 1);

int fd = open("/dev/mydev", O_RDWR);

write(fd, "something", strlen(string));

read(fd, result, strlen(string));
printf("result = %s\n", result);

close(fd);