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<table class="head">
<tr>
<td class="head-ltitle">VM_MAP_STACK(9)</td>
<td class="head-vol">Kernel Developer's Manual</td>
<td class="head-rtitle">VM_MAP_STACK(9)</td>
</tr>
</table>
<div class="manual-text">
<section class="Sh">
<h1 class="Sh" id="NAME"><a class="permalink" href="#NAME">NAME</a></h1>
<p class="Pp"><code class="Nm">vm_map_stack</code>,
<code class="Nm">vm_map_growstack</code> — <span class="Nd">manage
process stacks</span></p>
</section>
<section class="Sh">
<h1 class="Sh" id="SYNOPSIS"><a class="permalink" href="#SYNOPSIS">SYNOPSIS</a></h1>
<p class="Pp"><code class="In">#include
<<a class="In">sys/param.h</a>></code>
<br/>
<code class="In">#include <<a class="In">vm/vm.h</a>></code>
<br/>
<code class="In">#include <<a class="In">vm/vm_map.h</a>></code></p>
<p class="Pp"><var class="Ft">int</var>
<br/>
<code class="Fn">vm_map_stack</code>(<var class="Fa">vm_map_t map</var>,
<var class="Fa">vm_offset_t addrbos</var>, <var class="Fa">vm_size_t
max_ssize</var>, <var class="Fa">vm_prot_t prot</var>,
<var class="Fa">vm_prot_t max</var>, <var class="Fa">int cow</var>);</p>
<p class="Pp"><var class="Ft">int</var>
<br/>
<code class="Fn">vm_map_growstack</code>(<var class="Fa" style="white-space: nowrap;">struct
proc *p</var>, <var class="Fa" style="white-space: nowrap;">vm_offset_t
addr</var>);</p>
</section>
<section class="Sh">
<h1 class="Sh" id="DESCRIPTION"><a class="permalink" href="#DESCRIPTION">DESCRIPTION</a></h1>
<p class="Pp">The
<a class="permalink" href="#vm_map_stack"><code class="Fn" id="vm_map_stack">vm_map_stack</code></a>()
function maps a process stack for a new process image. The stack is mapped
<var class="Fa">addrbos</var> in <var class="Fa">map</var>, with a maximum
size of <var class="Fa">max_ssize</var>. Copy-on-write flags passed in
<var class="Fa">cow</var> are also applied to the new mapping. Protection
bits are supplied by <var class="Fa">prot</var> and
<var class="Fa">max</var>.</p>
<p class="Pp">It is typically called by <a class="Xr">execve(2)</a>.</p>
<p class="Pp" id="vm_map_growstack">The
<a class="permalink" href="#vm_map_growstack"><code class="Fn">vm_map_growstack</code></a>()
function is responsible for growing a stack for the process
<var class="Fa">p</var> to the desired address <var class="Fa">addr</var>,
similar to the legacy <a class="Xr">sbrk(2)</a> call.</p>
</section>
<section class="Sh">
<h1 class="Sh" id="IMPLEMENTATION_NOTES"><a class="permalink" href="#IMPLEMENTATION_NOTES">IMPLEMENTATION
NOTES</a></h1>
<p class="Pp">The <code class="Fn">vm_map_stack</code>() function calls
<a class="Xr">vm_map_insert(9)</a> to create its mappings.</p>
<p class="Pp">The <code class="Fn">vm_map_stack</code>() and
<code class="Fn">vm_map_growstack</code>() functions acquire the process
lock on <var class="Fa">p</var> for the duration of the call.</p>
</section>
<section class="Sh">
<h1 class="Sh" id="RETURN_VALUES"><a class="permalink" href="#RETURN_VALUES">RETURN
VALUES</a></h1>
<p class="Pp">The <code class="Fn">vm_map_stack</code>() function returns
<code class="Dv">KERN_SUCCESS</code> if the mapping was allocated
successfully.</p>
<p class="Pp">Otherwise, if mapping the stack would exceed the process's VMEM
resource limit, or if the specified bottom-of-stack address is out of range
for the map, or if there is already a mapping at the address which would
result, or if <var class="Fa">max_ssize</var> could not be accommodated
within the current mapping, <code class="Dv">KERN_NO_SPACE</code> is
returned.</p>
<p class="Pp">Other possible return values for this function are documented in
<a class="Xr">vm_map_insert(9)</a>.</p>
<p class="Pp">The <code class="Fn">vm_map_growstack</code>() function returns
<code class="Dv">KERN_SUCCESS</code> if <var class="Fa">addr</var> is
already mapped, or if the stack was grown successfully.</p>
<p class="Pp">It also returns <code class="Dv">KERN_SUCCESS</code> if
<var class="Fa">addr</var> is outside the stack range; this is done in order
to preserve compatibility with the deprecated <code class="Fn">grow</code>()
function previously located in the file
<span class="Pa">vm_machdep.c</span>.</p>
</section>
<section class="Sh">
<h1 class="Sh" id="SEE_ALSO"><a class="permalink" href="#SEE_ALSO">SEE
ALSO</a></h1>
<p class="Pp"><a class="Xr">vm_map(9)</a>,
<a class="Xr">vm_map_insert(9)</a></p>
</section>
<section class="Sh">
<h1 class="Sh" id="AUTHORS"><a class="permalink" href="#AUTHORS">AUTHORS</a></h1>
<p class="Pp">This manual page was written by <span class="An">Bruce M
Simpson</span>
<<a class="Mt" href="mailto:bms@spc.org">bms@spc.org</a>>.</p>
</section>
</div>
<table class="foot">
<tr>
<td class="foot-date">January 11, 2013</td>
<td class="foot-os">FreeBSD 15.0</td>
</tr>
</table>
|
