linux-stable/net/sunrpc/sysctl.c
Dan Carpenter ae2975046d net/sunrpc: fix useless comparison in proc_do_xprt()
In the original code, the "if (*lenp < 0)" check didn't work because
"*lenp" is unsigned.  Fortunately, the memory_read_from_buffer() call
will never fail in this context so it doesn't affect runtime.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2020-11-08 16:28:25 -05:00

193 lines
3.5 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/*
* linux/net/sunrpc/sysctl.c
*
* Sysctl interface to sunrpc module.
*
* I would prefer to register the sunrpc table below sys/net, but that's
* impossible at the moment.
*/
#include <linux/types.h>
#include <linux/linkage.h>
#include <linux/ctype.h>
#include <linux/fs.h>
#include <linux/sysctl.h>
#include <linux/module.h>
#include <linux/uaccess.h>
#include <linux/sunrpc/types.h>
#include <linux/sunrpc/sched.h>
#include <linux/sunrpc/stats.h>
#include <linux/sunrpc/svc_xprt.h>
#include "netns.h"
/*
* Declare the debug flags here
*/
unsigned int rpc_debug;
EXPORT_SYMBOL_GPL(rpc_debug);
unsigned int nfs_debug;
EXPORT_SYMBOL_GPL(nfs_debug);
unsigned int nfsd_debug;
EXPORT_SYMBOL_GPL(nfsd_debug);
unsigned int nlm_debug;
EXPORT_SYMBOL_GPL(nlm_debug);
#if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
static struct ctl_table_header *sunrpc_table_header;
static struct ctl_table sunrpc_table[];
void
rpc_register_sysctl(void)
{
if (!sunrpc_table_header)
sunrpc_table_header = register_sysctl_table(sunrpc_table);
}
void
rpc_unregister_sysctl(void)
{
if (sunrpc_table_header) {
unregister_sysctl_table(sunrpc_table_header);
sunrpc_table_header = NULL;
}
}
static int proc_do_xprt(struct ctl_table *table, int write,
void *buffer, size_t *lenp, loff_t *ppos)
{
char tmpbuf[256];
ssize_t len;
if (write || *ppos) {
*lenp = 0;
return 0;
}
len = svc_print_xprts(tmpbuf, sizeof(tmpbuf));
len = memory_read_from_buffer(buffer, *lenp, ppos, tmpbuf, len);
if (len < 0) {
*lenp = 0;
return -EINVAL;
}
*lenp = len;
return 0;
}
static int
proc_dodebug(struct ctl_table *table, int write, void *buffer, size_t *lenp,
loff_t *ppos)
{
char tmpbuf[20], *s = NULL;
char *p;
unsigned int value;
size_t left, len;
if ((*ppos && !write) || !*lenp) {
*lenp = 0;
return 0;
}
left = *lenp;
if (write) {
p = buffer;
while (left && isspace(*p)) {
left--;
p++;
}
if (!left)
goto done;
if (left > sizeof(tmpbuf) - 1)
return -EINVAL;
memcpy(tmpbuf, p, left);
tmpbuf[left] = '\0';
value = simple_strtol(tmpbuf, &s, 0);
if (s) {
left -= (s - tmpbuf);
if (left && !isspace(*s))
return -EINVAL;
while (left && isspace(*s)) {
left--;
s++;
}
} else
left = 0;
*(unsigned int *) table->data = value;
/* Display the RPC tasks on writing to rpc_debug */
if (strcmp(table->procname, "rpc_debug") == 0)
rpc_show_tasks(&init_net);
} else {
len = sprintf(tmpbuf, "0x%04x", *(unsigned int *) table->data);
if (len > left)
len = left;
memcpy(buffer, tmpbuf, len);
if ((left -= len) > 0) {
*((char *)buffer + len) = '\n';
left--;
}
}
done:
*lenp -= left;
*ppos += *lenp;
return 0;
}
static struct ctl_table debug_table[] = {
{
.procname = "rpc_debug",
.data = &rpc_debug,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dodebug
},
{
.procname = "nfs_debug",
.data = &nfs_debug,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dodebug
},
{
.procname = "nfsd_debug",
.data = &nfsd_debug,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dodebug
},
{
.procname = "nlm_debug",
.data = &nlm_debug,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dodebug
},
{
.procname = "transports",
.maxlen = 256,
.mode = 0444,
.proc_handler = proc_do_xprt,
},
{ }
};
static struct ctl_table sunrpc_table[] = {
{
.procname = "sunrpc",
.mode = 0555,
.child = debug_table
},
{ }
};
#endif