// SPDX-License-Identifier: GPL-2.0
/*
* HMC Drive FTP Services
*
* Copyright IBM Corp. 2013
* Author(s): Ralf Hoppe ([email protected])
*/
#define KMSG_COMPONENT "hmcdrv"
#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/uaccess.h>
#include <linux/export.h>
#include <linux/ctype.h>
#include <linux/crc16.h>
#include "hmcdrv_ftp.h"
#include "hmcdrv_cache.h"
#include "sclp_ftp.h"
#include "diag_ftp.h"
/**
* struct hmcdrv_ftp_ops - HMC drive FTP operations
* @startup: startup function
* @shutdown: shutdown function
* @transfer: FTP transfer function
*/
struct hmcdrv_ftp_ops {
int (*startup)(void);
void (*shutdown)(void);
ssize_t (*transfer)(const struct hmcdrv_ftp_cmdspec *ftp,
size_t *fsize);
};
static enum hmcdrv_ftp_cmdid hmcdrv_ftp_cmd_getid(const char *cmd, int len);
static int hmcdrv_ftp_parse(char *cmd, struct hmcdrv_ftp_cmdspec *ftp);
static const struct hmcdrv_ftp_ops *hmcdrv_ftp_funcs; /* current operations */
static DEFINE_MUTEX(hmcdrv_ftp_mutex); /* mutex for hmcdrv_ftp_funcs */
static unsigned hmcdrv_ftp_refcnt; /* start/shutdown reference counter */
/**
* hmcdrv_ftp_cmd_getid() - determine FTP command ID from a command string
* @cmd: FTP command string (NOT zero-terminated)
* @len: length of FTP command string in @cmd
*/
static enum hmcdrv_ftp_cmdid hmcdrv_ftp_cmd_getid(const char *cmd, int len)
{
/* HMC FTP command descriptor */
struct hmcdrv_ftp_cmd_desc {
const char *str; /* command string */
enum hmcdrv_ftp_cmdid cmd; /* associated command as enum */
};
/* Description of all HMC drive FTP commands
*
* Notes:
* 1. Array size should be a prime number.
* 2. Do not change the order of commands in table (because the
* index is determined by CRC % ARRAY_SIZE).
* 3. Original command 'nlist' was renamed, else the CRC would
* collide with 'append' (see point 2).
*/
static const struct hmcdrv_ftp_cmd_desc ftpcmds[7] = {
{.str = "get", /* [0] get (CRC = 0x68eb) */
.cmd = HMCDRV_FTP_GET},
{.str = "dir", /* [1] dir (CRC = 0x6a9e) */
.cmd = HMCDRV_FTP_DIR},
{.str = "delete", /* [2] delete (CRC = 0x53ae) */
.cmd = HMCDRV_FTP_DELETE},
{.str = "nls", /* [3] nls (CRC = 0xf87c) */
.cmd = HMCDRV_FTP_NLIST},
{.str = "put", /* [4] put (CRC = 0xac56) */
.cmd = HMCDRV_FTP_PUT},
{.str = "append", /* [5] append (CRC = 0xf56e) */
.cmd = HMCDRV_FTP_APPEND},
{.str = NULL} /* [6] unused */
};
const struct hmcdrv_ftp_cmd_desc *pdesc;
u16 crc = 0xffffU;
if (len == 0)
return HMCDRV_FTP_NOOP; /* error indiactor */
crc = crc16(crc, cmd, len);
pdesc = ftpcmds + (crc % ARRAY_SIZE(ftpcmds));
pr_debug("FTP command '%s' has CRC 0x%04x, at table pos. %lu\n",
cmd, crc, (crc % ARRAY_SIZE(ftpcmds)));
if (!pdesc->str || strncmp(pdesc->str, cmd, len))
return HMCDRV_FTP_NOOP;
pr_debug("FTP command '%s' found, with ID %d\n",
pdesc->str, pdesc->cmd);
return pdesc->cmd;
}
/**
* hmcdrv_ftp_parse() - HMC drive FTP command parser
* @cmd: FTP command string "<cmd> <filename>"
* @ftp: Pointer to FTP command specification buffer (output)
*
* Return: 0 on success, else a (negative) error code
*/
static int hmcdrv_ftp_parse(char *cmd, struct hmcdrv_ftp_cmdspec *ftp)
{
char *start;
int argc = 0;
ftp->id = HMCDRV_FTP_NOOP;
ftp->fname = NULL;
while (*cmd != '\0') {
while (isspace(*cmd))
++cmd;
if (*cmd == '\0')
break;
start = cmd;
switch (argc) {
case 0: /* 1st argument (FTP command) */
while ((*cmd != '\0') && !isspace(*cmd))
++cmd;
ftp->id = hmcdrv_ftp_cmd_getid(start, cmd - start);
break;
case 1: /* 2nd / last argument (rest of line) */
while ((*cmd != '\0') && !iscntrl(*cmd))
++cmd;
ftp->fname = start;
fallthrough;
default:
*cmd = '\0';
break;
} /* switch */
++argc;
} /* while */
if (!ftp->fname || (ftp->id == HMCDRV_FTP_NOOP))
return -EINVAL;
return 0;
}
/**
* hmcdrv_ftp_do() - perform a HMC drive FTP, with data from kernel-space
* @ftp: pointer to FTP command specification
*
* Return: number of bytes read/written or a negative error code
*/
ssize_t hmcdrv_ftp_do(const struct hmcdrv_ftp_cmdspec *ftp)
{
ssize_t len;
mutex_lock(&hmcdrv_ftp_mutex);
if (hmcdrv_ftp_funcs && hmcdrv_ftp_refcnt) {
pr_debug("starting transfer, cmd %d for '%s' at %lld with %zd bytes\n",
ftp->id, ftp->fname, (long long) ftp->ofs, ftp->len);
len = hmcdrv_cache_cmd(ftp, hmcdrv_ftp_funcs->transfer);
} else {
len = -ENXIO;
}
mutex_unlock(&hmcdrv_ftp_mutex);
return len;
}
EXPORT_SYMBOL(hmcdrv_ftp_do);
/**
* hmcdrv_ftp_probe() - probe for the HMC drive FTP service
*
* Return: 0 if service is available, else an (negative) error code
*/
int hmcdrv_ftp_probe(void)
{
int rc;
struct hmcdrv_ftp_cmdspec ftp = {
.id = HMCDRV_FTP_NOOP,
.ofs = 0,
.fname = "",
.len = PAGE_SIZE
};
ftp.buf = (void *) get_zeroed_page(GFP_KERNEL | GFP_DMA);
if (!ftp.buf)
return -ENOMEM;
rc = hmcdrv_ftp_startup();
if (rc)
goto out;
rc = hmcdrv_ftp_do(&ftp);
hmcdrv_ftp_shutdown();
switch (rc) {
case -ENOENT: /* no such file/media or currently busy, */
case -EBUSY: /* but service seems to be available */
rc = 0;
break;
default: /* leave 'rc' as it is for [0, -EPERM, -E...] */
if (rc > 0)
rc = 0; /* clear length (success) */
break;
} /* switch */
out:
free_page((unsigned long) ftp.buf);
return rc;
}
EXPORT_SYMBOL(hmcdrv_ftp_probe);
/**
* hmcdrv_ftp_cmd() - Perform a HMC drive FTP, with data from user-space
*
* @cmd: FTP command string "<cmd> <filename>"
* @offset: file position to read/write
* @buf: user-space buffer for read/written directory/file
* @len: size of @buf (read/dir) or number of bytes to write
*
* This function must not be called before hmcdrv_ftp_startup() was called.
*
* Return: number of bytes read/written or a negative error code
*/
ssize_t hmcdrv_ftp_cmd(char __kernel *cmd, loff_t offset,
char __user *buf, size_t len)
{
int order;
struct hmcdrv_ftp_cmdspec ftp = {.len = len, .ofs = offset};
ssize_t retlen = hmcdrv_ftp_parse(cmd, &ftp);
if (retlen)
return retlen;
order = get_order(ftp.len);
ftp.buf = (void *) __get_free_pages(GFP_KERNEL | GFP_DMA, order);
if (!ftp.buf)
return -ENOMEM;
switch (ftp.id) {
case HMCDRV_FTP_DIR:
case HMCDRV_FTP_NLIST:
case HMCDRV_FTP_GET:
retlen = hmcdrv_ftp_do(&ftp);
if ((retlen >= 0) &&
copy_to_user(buf, ftp.buf, retlen))
retlen = -EFAULT;
break;
case HMCDRV_FTP_PUT:
case HMCDRV_FTP_APPEND:
if (!copy_from_user(ftp.buf, buf, ftp.len))
retlen = hmcdrv_ftp_do(&ftp);
else
retlen = -EFAULT;
break;
case HMCDRV_FTP_DELETE:
retlen = hmcdrv_ftp_do(&ftp);
break;
default:
retlen = -EOPNOTSUPP;
break;
}
free_pages((unsigned long) ftp.buf, order);
return retlen;
}
/**
* hmcdrv_ftp_startup() - startup of HMC drive FTP functionality for a
* dedicated (owner) instance
*
* Return: 0 on success, else an (negative) error code
*/
int hmcdrv_ftp_startup(void)
{
static const struct hmcdrv_ftp_ops hmcdrv_ftp_zvm = {
.startup = diag_ftp_startup,
.shutdown = diag_ftp_shutdown,
.transfer = diag_ftp_cmd
};
static const struct hmcdrv_ftp_ops hmcdrv_ftp_lpar = {
.startup = sclp_ftp_startup,
.shutdown = sclp_ftp_shutdown,
.transfer = sclp_ftp_cmd
};
int rc = 0;
mutex_lock(&hmcdrv_ftp_mutex); /* block transfers while start-up */
if (hmcdrv_ftp_refcnt == 0) {
if (MACHINE_IS_VM)
hmcdrv_ftp_funcs = &hmcdrv_ftp_zvm;
else if (MACHINE_IS_LPAR || MACHINE_IS_KVM)
hmcdrv_ftp_funcs = &hmcdrv_ftp_lpar;
else
rc = -EOPNOTSUPP;
if (hmcdrv_ftp_funcs)
rc = hmcdrv_ftp_funcs->startup();
}
if (!rc)
++hmcdrv_ftp_refcnt;
mutex_unlock(&hmcdrv_ftp_mutex);
return rc;
}
EXPORT_SYMBOL(hmcdrv_ftp_startup);
/**
* hmcdrv_ftp_shutdown() - shutdown of HMC drive FTP functionality for a
* dedicated (owner) instance
*/
void hmcdrv_ftp_shutdown(void)
{
mutex_lock(&hmcdrv_ftp_mutex);
--hmcdrv_ftp_refcnt;
if ((hmcdrv_ftp_refcnt == 0) && hmcdrv_ftp_funcs)
hmcdrv_ftp_funcs->shutdown();
mutex_unlock(&hmcdrv_ftp_mutex);
}
EXPORT_SYMBOL(hmcdrv_ftp_shutdown);
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