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[ts-7000] Re: open("/dev/mem", O_RDWR) returns -1

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Subject: [ts-7000] Re: open("/dev/mem", O_RDWR) returns -1
From: "Fred" <>
Date: Tue, 02 Sep 2008 16:26:00 -0000
--- In "sccjazz1" <> wrote:
> The permisions on the executable 
> are 777, the permisions on /dev/mem 
> are 777. I can invoke a 'Hello World' 
> executable just fine via the web page 
> button.(FYI). The executable is in 
> the cgi-bin directory.  The problem 
> is the open("/dev/mem",O_RDWR) 
> statement returns a -1.

How about displaying the value of errno
to see what other information might be
available?  errno should be one of the
following problems:

EACCES 
The requested access to the file is not allowed, or search permission 
is denied for one of the directories in the path prefix of pathname, 
or the file did not exist yet and write access to the parent 
directory is not allowed. (See also path_resolution(2).) 

EEXIST 
pathname already exists and O_CREAT and O_EXCL were used. 

EFAULT 
pathname points outside your accessible address space. 

EISDIR 
pathname refers to a directory and the access requested involved 
writing (that is, O_WRONLY or O_RDWR is set). 

ELOOP 
Too many symbolic links were encountered in resolving pathname, or 
O_NOFOLLOW was specified but pathname was a symbolic link. 

EMFILE 
The process already has the maximum number of files open. 

ENAMETOOLONG 
pathname was too long. 

ENFILE 
The system limit on the total number of open files has been reached. 

ENODEV 
pathname refers to a device special file and no corresponding device 
exists. (This is a Linux kernel bug; in this situation ENXIO must be 
returned.) 

ENOENT 
O_CREAT is not set and the named file does not exist. Or, a directory 
component in pathname does not exist or is a dangling symbolic link. 

ENOMEM 
Insufficient kernel memory was available. 

ENOSPC 
pathname was to be created but the device containing pathname has no 
room for the new file. 

ENOTDIR 
A component used as a directory in pathname is not, in fact, a 
directory, or O_DIRECTORY was specified and pathname was not a 
directory. 

ENXIO 
O_NONBLOCK | O_WRONLY is set, the named file is a FIFO and no process 
has the file open for reading. Or, the file is a device special file 
and no corresponding device exists. 

EOVERFLOW 
pathname refers to a regular file, too large to be opened; see 
O_LARGEFILE above. 

EPERM 
The O_NOATIME flag was specified, but the effective user ID of the 
caller did not match the owner of the file and the caller was not 
privileged (CAP_FOWNER). 

EROFS 
pathname refers to a file on a read-only filesystem and write access 
was requested. 

ETXTBSY 
pathname refers to an executable image which is currently being 
executed and write access was requested. 

EWOULDBLOCK 
The O_NONBLOCK flag was specified, and an incompatible lease was held 
on the file (see fcntl(2)).



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