--- /dev/null
+/*
+ * HMC Drive FTP Services
+ *
+ * Copyright IBM Corp. 2013
+ * Author(s): Ralf Hoppe (rhoppe@de.ibm.com)
+ */
+
+#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
+ * @cmd: 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 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;
+ /* fall through */
+ 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 struct hmcdrv_ftp_ops hmcdrv_ftp_zvm = {
+ .startup = diag_ftp_startup,
+ .shutdown = diag_ftp_shutdown,
+ .transfer = diag_ftp_cmd
+ };
+
+ static 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);
Code Review / kvmfornfv.git / blobdiff