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Code Issues Releases Wiki Activity

Fix sleep example

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This commit is contained in:
Bob Mottram
2016-03-21 15:34:17 +00:00
parent eabe2b2981
commit e4e6993f19
2 changed files with 33 additions and 125 deletions
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80
LKMPG-3.16.html
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@@ -3,7 +3,7 @@
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" lang="en" xml:lang="en">
<head>
<!-- 2016-03-21 Mon 15:11 -->
<!-- 2016-03-21 Mon 15:34 -->
<meta http-equiv="Content-Type" content="text/html;charset=utf-8" />
<meta name="viewport" content="width=device-width, initial-scale=1" />
<title>The Linux Kernel Module Programming Guide</title>
@@ -3520,7 +3520,7 @@ DECLARE_WAIT_QUEUE_HEAD(WaitQ);
<span class="org-keyword">for</span> (i = 0; i &lt; _NSIG_WORDS &amp;&amp; <span class="org-negation-char">!</span>is_sig; i++)
is_sig =
current-&gt;pending.signal.sig[i] &amp; ~current-&gt;
blocked.sig[i];
blocked.sig[i];
<span class="org-keyword">if</span> (is_sig) {
<span class="org-comment-delimiter">/*</span>
@@ -3545,8 +3545,8 @@ DECLARE_WAIT_QUEUE_HEAD(WaitQ);
<span class="org-comment-delimiter">/*</span>
<span class="org-comment"> * Open the file</span>
<span class="org-comment"> </span><span class="org-comment-delimiter">*/</span>
Already_Open = 1;
<span class="org-keyword">return</span> 0; <span class="org-comment-delimiter">/* </span><span class="org-comment">Allow the access </span><span class="org-comment-delimiter">*/</span>
Already_Open = 1;
<span class="org-keyword">return</span> 0; <span class="org-comment-delimiter">/* </span><span class="org-comment">Allow the access </span><span class="org-comment-delimiter">*/</span>
}
<span class="org-comment-delimiter">/*</span>
@@ -3573,33 +3573,6 @@ DECLARE_WAIT_QUEUE_HEAD(WaitQ);
<span class="org-keyword">return</span> 0; <span class="org-comment-delimiter">/* </span><span class="org-comment">success </span><span class="org-comment-delimiter">*/</span>
}
<span class="org-comment-delimiter">/*</span>
<span class="org-comment"> * This function decides whether to allow an operation (return zero) or not</span>
<span class="org-comment"> * allow it (return a non-zero which indicates why it is not allowed).</span>
<span class="org-comment"> *</span>
<span class="org-comment"> * The operation can be one of the following values:</span>
<span class="org-comment"> * 0 - Execute (run the "file" - meaningless in our case)</span>
<span class="org-comment"> * 2 - Write (input to the kernel module)</span>
<span class="org-comment"> * 4 - Read (output from the kernel module)</span>
<span class="org-comment"> *</span>
<span class="org-comment"> * This is the real function that checks file permissions. The permissions</span>
<span class="org-comment"> * returned by ls -l are for reference only, and can be overridden here.</span>
<span class="org-comment"> </span><span class="org-comment-delimiter">*/</span>
<span class="org-keyword">static</span> <span class="org-type">int</span> <span class="org-function-name">module_permission</span>(<span class="org-keyword">struct</span> <span class="org-type">inode</span> *<span class="org-variable-name">inode</span>, <span class="org-type">int</span> <span class="org-variable-name">op</span>, <span class="org-keyword">struct</span> <span class="org-type">nameidata</span> *<span class="org-variable-name">nd</span>)
{
<span class="org-comment-delimiter">/*</span>
<span class="org-comment"> * We allow everybody to read from our module, but only root (uid 0)</span>
<span class="org-comment"> * may write to it</span>
<span class="org-comment"> </span><span class="org-comment-delimiter">*/</span>
<span class="org-keyword">if</span> (op == 4 || (op == 2 &amp;&amp; current-&gt;euid == 0))
<span class="org-keyword">return</span> 0;
<span class="org-comment-delimiter">/*</span>
<span class="org-comment"> * If it's anything else, access is denied</span>
<span class="org-comment"> </span><span class="org-comment-delimiter">*/</span>
<span class="org-keyword">return</span> -EACCES;
}
<span class="org-comment-delimiter">/*</span>
<span class="org-comment"> * Structures to register as the /proc file, with pointers to all the relevant</span>
<span class="org-comment"> * functions.</span>
@@ -3611,22 +3584,10 @@ DECLARE_WAIT_QUEUE_HEAD(WaitQ);
<span class="org-comment"> * means we don't want to deal with something.</span>
<span class="org-comment"> </span><span class="org-comment-delimiter">*/</span>
<span class="org-keyword">static</span> <span class="org-keyword">struct</span> <span class="org-type">file_operations</span> <span class="org-variable-name">File_Ops_4_Our_Proc_File</span> = {
.read = module_output, <span class="org-comment-delimiter">/* </span><span class="org-comment">"read" from the file </span><span class="org-comment-delimiter">*/</span>
.write = module_input, <span class="org-comment-delimiter">/* </span><span class="org-comment">"write" to the file </span><span class="org-comment-delimiter">*/</span>
.open = module_open, <span class="org-comment-delimiter">/* </span><span class="org-comment">called when the /proc file is opened </span><span class="org-comment-delimiter">*/</span>
.release = module_close, <span class="org-comment-delimiter">/* </span><span class="org-comment">called when it's closed </span><span class="org-comment-delimiter">*/</span>
};
<span class="org-comment-delimiter">/*</span>
<span class="org-comment"> * Inode operations for our proc file. We need it so we'll have somewhere to</span>
<span class="org-comment"> * specify the file operations structure we want to use, and the function we</span>
<span class="org-comment"> * use for permissions. It's also possible to specify functions to be called</span>
<span class="org-comment"> * for anything else which could be done to an inode (although we don't bother,</span>
<span class="org-comment"> * we just put NULL).</span>
<span class="org-comment"> </span><span class="org-comment-delimiter">*/</span>
<span class="org-keyword">static</span> <span class="org-keyword">struct</span> <span class="org-type">inode_operations</span> <span class="org-variable-name">Inode_Ops_4_Our_Proc_File</span> = {
.permission = module_permission, <span class="org-comment-delimiter">/* </span><span class="org-comment">check for permissions </span><span class="org-comment-delimiter">*/</span>
.read = module_output, <span class="org-comment-delimiter">/* </span><span class="org-comment">"read" from the file </span><span class="org-comment-delimiter">*/</span>
.write = module_input, <span class="org-comment-delimiter">/* </span><span class="org-comment">"write" to the file </span><span class="org-comment-delimiter">*/</span>
.open = module_open, <span class="org-comment-delimiter">/* </span><span class="org-comment">called when the /proc file is opened </span><span class="org-comment-delimiter">*/</span>
.release = module_close, <span class="org-comment-delimiter">/* </span><span class="org-comment">called when it's closed </span><span class="org-comment-delimiter">*/</span>
};
<span class="org-comment-delimiter">/*</span>
@@ -3639,21 +3600,15 @@ DECLARE_WAIT_QUEUE_HEAD(WaitQ);
<span class="org-type">int</span> <span class="org-function-name">init_module</span>()
{
Our_Proc_File = create_proc_entry(PROC_ENTRY_FILENAME, 0644, <span class="org-constant">NULL</span>);
<span class="org-keyword">if</span> (Our_Proc_File == <span class="org-constant">NULL</span>) {
remove_proc_entry(PROC_ENTRY_FILENAME, &amp;proc_root);
printk(KERN_ALERT <span class="org-string">"Error: Could not initialize /proc/test\n"</span>);
Our_Proc_File = proc_create(PROC_ENTRY_FILENAME, 0644, <span class="org-constant">NULL</span>, &amp;File_Ops_4_Our_Proc_File);
<span class="org-keyword">if</span>(Our_Proc_File == <span class="org-constant">NULL</span>)
{
remove_proc_entry(PROC_ENTRY_FILENAME, <span class="org-constant">NULL</span>);
printk(KERN_DEBUG <span class="org-string">"Error: Could not initialize /proc/%s\n"</span>, PROC_ENTRY_FILENAME);
<span class="org-keyword">return</span> -ENOMEM;
}
Our_Proc_File-&gt;owner = THIS_MODULE;
Our_Proc_File-&gt;proc_iops = &amp;Inode_Ops_4_Our_Proc_File;
Our_Proc_File-&gt;proc_fops = &amp;File_Ops_4_Our_Proc_File;
Our_Proc_File-&gt;mode = S_IFREG | S_IRUGO | S_IWUSR;
Our_Proc_File-&gt;uid = 0;
Our_Proc_File-&gt;gid = 0;
Our_Proc_File-&gt;size = 80;
proc_set_size(Our_Proc_File, 80);
proc_set_user(Our_Proc_File, GLOBAL_ROOT_UID, GLOBAL_ROOT_GID);
printk(KERN_INFO <span class="org-string">"/proc/test created\n"</span>);
@@ -3668,9 +3623,8 @@ DECLARE_WAIT_QUEUE_HEAD(WaitQ);
<span class="org-comment"> </span><span class="org-comment-delimiter">*/</span>
<span class="org-type">void</span> <span class="org-function-name">cleanup_module</span>()
{
remove_proc_entry(PROC_ENTRY_FILENAME, &amp;proc_root);
printk(KERN_INFO <span class="org-string">"/proc/test removed\n"</span>);
remove_proc_entry(PROC_ENTRY_FILENAME, <span class="org-constant">NULL</span>);
printk(KERN_DEBUG <span class="org-string">"/proc/%s removed\n"</span>, PROC_ENTRY_FILENAME);
}
</pre>
</div>

78
LKMPG-3.16.org
View File

@@ -2462,7 +2462,7 @@ static int module_open(struct inode *inode, struct file *file)
for (i = 0; i < _NSIG_WORDS && !is_sig; i++)
is_sig =
current->pending.signal.sig[i] & ~current->
blocked.sig[i];
blocked.sig[i];
if (is_sig) {
/*
@@ -2487,8 +2487,8 @@ static int module_open(struct inode *inode, struct file *file)
/*
* Open the file
*/
Already_Open = 1;
return 0; /* Allow the access */
Already_Open = 1;
return 0; /* Allow the access */
}
/*
@@ -2515,33 +2515,6 @@ int module_close(struct inode *inode, struct file *file)
return 0; /* success */
}
/*
* This function decides whether to allow an operation (return zero) or not
* allow it (return a non-zero which indicates why it is not allowed).
*
* The operation can be one of the following values:
* 0 - Execute (run the "file" - meaningless in our case)
* 2 - Write (input to the kernel module)
* 4 - Read (output from the kernel module)
*
* This is the real function that checks file permissions. The permissions
* returned by ls -l are for reference only, and can be overridden here.
*/
static int module_permission(struct inode *inode, int op, struct nameidata *nd)
{
/*
* We allow everybody to read from our module, but only root (uid 0)
* may write to it
*/
if (op == 4 || (op == 2 && current->euid == 0))
return 0;
/*
* If it's anything else, access is denied
*/
return -EACCES;
}
/*
* Structures to register as the /proc file, with pointers to all the relevant
* functions.
@@ -2553,22 +2526,10 @@ static int module_permission(struct inode *inode, int op, struct nameidata *nd)
* means we don't want to deal with something.
*/
static struct file_operations File_Ops_4_Our_Proc_File = {
.read = module_output, /* "read" from the file */
.write = module_input, /* "write" to the file */
.open = module_open, /* called when the /proc file is opened */
.release = module_close, /* called when it's closed */
};
/*
* Inode operations for our proc file. We need it so we'll have somewhere to
* specify the file operations structure we want to use, and the function we
* use for permissions. It's also possible to specify functions to be called
* for anything else which could be done to an inode (although we don't bother,
* we just put NULL).
*/
static struct inode_operations Inode_Ops_4_Our_Proc_File = {
.permission = module_permission, /* check for permissions */
.read = module_output, /* "read" from the file */
.write = module_input, /* "write" to the file */
.open = module_open, /* called when the /proc file is opened */
.release = module_close, /* called when it's closed */
};
/*
@@ -2581,21 +2542,15 @@ static struct inode_operations Inode_Ops_4_Our_Proc_File = {
int init_module()
{
Our_Proc_File = create_proc_entry(PROC_ENTRY_FILENAME, 0644, NULL);
if (Our_Proc_File == NULL) {
remove_proc_entry(PROC_ENTRY_FILENAME, &proc_root);
printk(KERN_ALERT "Error: Could not initialize /proc/test\n");
Our_Proc_File = proc_create(PROC_ENTRY_FILENAME, 0644, NULL, &File_Ops_4_Our_Proc_File);
if(Our_Proc_File == NULL)
{
remove_proc_entry(PROC_ENTRY_FILENAME, NULL);
printk(KERN_DEBUG "Error: Could not initialize /proc/%s\n", PROC_ENTRY_FILENAME);
return -ENOMEM;
}
Our_Proc_File->owner = THIS_MODULE;
Our_Proc_File->proc_iops = &Inode_Ops_4_Our_Proc_File;
Our_Proc_File->proc_fops = &File_Ops_4_Our_Proc_File;
Our_Proc_File->mode = S_IFREG | S_IRUGO | S_IWUSR;
Our_Proc_File->uid = 0;
Our_Proc_File->gid = 0;
Our_Proc_File->size = 80;
proc_set_size(Our_Proc_File, 80);
proc_set_user(Our_Proc_File, GLOBAL_ROOT_UID, GLOBAL_ROOT_GID);
printk(KERN_INFO "/proc/test created\n");
@@ -2610,9 +2565,8 @@ int init_module()
*/
void cleanup_module()
{
remove_proc_entry(PROC_ENTRY_FILENAME, &proc_root);
printk(KERN_INFO "/proc/test removed\n");
remove_proc_entry(PROC_ENTRY_FILENAME, NULL);
printk(KERN_DEBUG "/proc/%s removed\n", PROC_ENTRY_FILENAME);
}
#+END_SRC