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| -rw-r--r-- | man2/delete_module.2 | 135 |
1 files changed, 123 insertions, 12 deletions
diff --git a/man2/delete_module.2 b/man2/delete_module.2 index 115c24cc51..2c8ecf3361 100644 --- a/man2/delete_module.2 +++ b/man2/delete_module.2 @@ -1,27 +1,92 @@ .\" Copyright (C) 1996 Free Software Foundation, Inc. +.\" and Copyright (C) 2012 Michael Kerrisk <mtk.manpages@gmail.com> .\" This file is distributed according to the GNU General Public License. .\" See the file COPYING in the top level source directory for details. .\" .\" 2006-02-09, some reformatting by Luc Van Oostenryck; some .\" reformatting and rewordings by mtk .\" -.TH DELETE_MODULE 2 2012-10-08 "Linux" "Linux Programmer's Manual" +.TH DELETE_MODULE 2 2012-10-09 "Linux" "Linux Programmer's Manual" .SH NAME -delete_module \- delete a loadable module entry +delete_module \- unload a kernel module .SH SYNOPSIS .nf -.B #include <linux/module.h> -.sp -.BI "int delete_module(const char *" name ); +.BI "int delete_module(const char *" name ", int " flags ); .fi + +.IR Note : +There is no glibc wrapper for this system call; see NOTES. .SH DESCRIPTION .BR delete_module () -attempts to remove an unused loadable module entry. -If -.I name -is NULL, -all unused modules marked auto-clean will be removed. +attempts to remove the unused loadable module entry +identified by +.IR name . This system call requires privilege. + +If there are other loaded modules that depend on +(i.e., refer to symbols defined in) this module, +then the call fails. +Otherwise, by default, +.BR delete_module () +marks a module so that no new references are permitted. +If the module's reference count +(i.e., the number of processes currently using the module) is nonzero, +it then places the caller in an uninterruptible sleep +state until all reference count is zero, +at which point the call unblocks. +When the reference count reaches zero, the module is unloaded. +When the module is unloaded, the kernel executes its +.I exit +function. + +The +.IR flags +argument can be used to modify the behavior of the system call. +The following values can be ORed in this argument: +.TP +.B O_TRUNC +.\" KMOD_REMOVE_FORCE in kmod library +Force unloading of the module, even if the following conditions are true: +.RS +.IP * 3 +The module has no +.I exit +function. +By default, attempting to unload a module that has no +.I exit +function fails. +.IP * +The reference count for (i.e., the number of processes currently using) +this module is nonzero. +See the description of +.BR O_NONBLOCK . +.RE +.IP +Using this flag taints the kernel (TAINT_FORCED_RMMOD). +.IP +.IR "Using this flag is dangerous!" +If the kernel was not built with +.BR CONFIG_MODULE_FORCE_UNLOAD , +this flag is silently ignored. +.TP +.B O_NONBLOCK +.\" KMOD_REMOVE_NOWAIT in kmod library +If both +.B O_NONBLOCK +and +.B O_TRUNC +are specified in +.IR flags +(and the kernel was built with +.BR CONFIG_MODULE_FORCE_UNLOAD ), +then the module is unloaded immediately, +regardless of whether it has a nonzero reference count. +If +.B O_NONBLOCK +was specified, but +.B O_TRUNC +was not, then an error is returned +if the module has a nonzero reference count. .SH "RETURN VALUE" On success, zero is returned. On error, \-1 is returned and @@ -30,7 +95,15 @@ is set appropriately. .SH ERRORS .TP .B EBUSY -The module is in use. +The module is not "live" +(i.e., it is still being initialized or is already marked for removal); +or, the module has no +.I exit +function and +.B O_TRUNC +was not specified in +.IR flags . + .TP .B EFAULT .I name @@ -47,10 +120,48 @@ No module by that name exists. The caller was not privileged (did not have the .B CAP_SYS_MODULE -capability). +capability), +or module unloading is disabled +(see +.IR /proc/sys/kernel/modules_disabled +in +.BR proc (5)). +.TP +.B EWOULDBLOCK +Other modules depend on this module; +or, +.BR O_NONBLOCK +was specified in +.IR flags , +but the reference count of this module is nonzero and +.B O_TRUNC +was not specified in +.IR flags . .SH "CONFORMING TO" .BR delete_module () is Linux-specific. +.SH NOTES +Glibc does not provide a wrapper for this system call; call it using +.BR syscall (2). + +See the Linux kernel source file +.I include/linux/module.h +for some useful background information. + +.SS Linux 2.4 and earlier +In Linux 2.4 and earlier, the system call took only one argument: + +.BI " int delete_module(const char *" name ); + +If +.I name +is NULL, all unused modules marked auto-clean are removed. + +Some further details of differences in the behavior of +.BR delete_module () +in Linux 2.4 and earlier are +.I not +currently explained in this manual page. .SH "SEE ALSO" .BR create_module (2), .BR init_module (2), |