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rmmod.c
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rmmod.c
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/* rmmod.c: remove a module from the kernel.
Copyright (C) 2001 Rusty Russell.
Copyright (C) 2002 Rusty Russell, IBM Corporation.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>
#include <fcntl.h>
#include <asm/unistd.h>
#include <stdarg.h>
#include <getopt.h>
#include <syslog.h>
#include "util.h"
#include "logging.h"
#include "testing.h"
extern long delete_module(const char *, unsigned int);
static char *next_field(const char *line)
{
const char *rest;
rest = line + strcspn(line, " ");
rest += strspn(rest, " ");
return (char *)rest;
}
/* Report that the module is in use. */
static void mod_in_use(const char *modname, char *usedby)
{
/* New /proc/modules uses a single "-" to mean "nothing". Old
one just puts nothing there. */
if (usedby[0] == '-' || streq(usedby, "")) {
error("Module %s is in use\n", modname);
return;
}
/* New /proc/modules *always* prints commas (even if only one) */
if (strchr(usedby, ','))
/* Blatt over trailing comma for neatness */
usedby[strcspn(usedby, " \n")-1] = '\0';
else {
/* Older /proc/modules just put them as
space-separated names. Blatt over trailing \n */
usedby[strlen(usedby)-1] = '\0';
}
error("Module %s is in use by %s\n", modname, usedby);
}
/* If we can check usage without entering kernel, do so. */
static int check_usage(const char *modname)
{
FILE *module_list;
char line[10240], name[64];
unsigned long size, refs;
int scanned;
module_list = fopen("/proc/modules", "r");
if (!module_list) {
if (errno == ENOENT) /* /proc may not be mounted. */
return 0;
fatal("can't open /proc/modules: %s\n", strerror(errno));
}
while (fgets(line, sizeof(line)-1, module_list) != NULL) {
if (strchr(line, '\n') == NULL) {
fatal("V. v. long line broke rmmod.\n");
exit(1);
}
scanned = sscanf(line, "%s %lu %lu", name, &size, &refs);
if (strcmp(name, modname) != 0)
continue;
if (scanned < 2)
fatal("Unknown format in /proc/modules: %s\n", line);
if (scanned == 2)
fatal("Kernel does not have unload support.\n");
/* Hand it fields 3 onwards. */
if (refs != 0)
mod_in_use(modname,
next_field(next_field(next_field(line))));
goto out;
}
error("Module %s does not exist in /proc/modules\n", modname);
refs = 1;
out:
fclose(module_list);
return (refs == 0) ? 0 : -EINVAL;
}
static int rmmod(const char *path, int flags)
{
long ret;
char name[strlen(path) + 1];
filename2modname(name, path);
if ((flags & O_NONBLOCK) && !(flags & O_TRUNC)) {
if (check_usage(name) != 0)
return 1;
}
info("rmmod %s, wait=%s%s\n", name,
(flags & O_NONBLOCK) ? "no" : "yes",
(flags & O_TRUNC) ? " force" : "");
ret = delete_module(name, flags);
if (ret != 0)
error("Removing '%s': %s\n", name, strerror(errno));
return ret;
}
static const struct option options[] = { { "all", 0, NULL, 'a' },
{ "force", 0, NULL, 'f' },
{ "help", 0, NULL, 'h' },
{ "syslog", 0, NULL, 's' },
{ "verbose", 0, NULL, 'v' },
{ "version", 0, NULL, 'V' },
{ "wait", 0, NULL, 'w' },
{ NULL, 0, NULL, 0 } };
static void print_usage(const char *progname)
{
fprintf(stderr,
"Usage: %s [-fhswvV] modulename ...\n"
// " -a (or --all) to remove all modules (no names needed)\n"
" -f (or --force) forces a module unload, and may crash your\n"
" machine. This requires the Forced Module Removal option\n"
" when the kernel was compiled.\n"
" -h (or --help) prints this help text\n"
" -s (or --syslog) says use syslog, not stderr\n"
" -v (or --verbose) enables more messages\n"
" -V (or --version) prints the version code\n"
" -w (or --wait) begins a module removal even if it is used\n"
" and will stop new users from accessing the module (so it\n"
" should eventually fall to zero).\n"
, progname);
exit(1);
}
int main(int argc, char *argv[])
{
/* O_EXCL so kernels can spot old rmmod versions */
unsigned int flags = O_NONBLOCK|O_EXCL;
int i, opt, all = 0;
int ret, err;
while ((opt = getopt_long(argc, argv,
"afh?swvV", options, NULL)) != EOF) {
switch (opt) {
case 'a': // --all
all = 1;
break;
case 'f': // --force
flags |= O_TRUNC;
break;
case 's': // --syslog
openlog("rmmod", LOG_CONS, LOG_DAEMON);
logging = 1;
break;
case 'w': // --wait
flags &= ~O_NONBLOCK;
break;
case 'v': // --verbose
verbose++;
break;
case 'V': // --version
puts(PACKAGE " version " VERSION);
return 0;
default:
print_usage(argv[0]);
}
}
if (!argv[optind]) {
fprintf(stderr, "no module names given\n");
print_usage(argv[0]);
}
err = 0;
/* remove each specified module */
for (i = optind; i < argc; i++) {
ret = rmmod(argv[i], flags);
if (ret != 0)
err = 1;
}
if (logging)
closelog();
exit(err);
}