diff options
Diffstat (limited to '')
-rw-r--r-- | drivers/s390/char/hmcdrv_ftp.c | 344 |
1 files changed, 344 insertions, 0 deletions
diff --git a/drivers/s390/char/hmcdrv_ftp.c b/drivers/s390/char/hmcdrv_ftp.c new file mode 100644 index 000000000..02b6f394a --- /dev/null +++ b/drivers/s390/char/hmcdrv_ftp.c @@ -0,0 +1,344 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * 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 + * @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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