/* * storage_common.c -- Common definitions for mass storage functionality * * Copyright (C) 2003-2008 Alan Stern * Copyeight (C) 2009 Samsung Electronics * Author: Michal Nazarewicz (m.nazarewicz@samsung.com) * * 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 file requires the following identifiers used in USB strings to * be defined (each of type pointer to char): * - fsg_string_manufacturer -- name of the manufacturer * - fsg_string_product -- name of the product * - fsg_string_config -- name of the configuration * - fsg_string_interface -- name of the interface * The first four are only needed when FSG_DESCRIPTORS_DEVICE_STRINGS * macro is defined prior to including this file. */ /* * When FSG_NO_INTR_EP is defined fsg_fs_intr_in_desc and * fsg_hs_intr_in_desc objects as well as * FSG_FS_FUNCTION_PRE_EP_ENTRIES and FSG_HS_FUNCTION_PRE_EP_ENTRIES * macros are not defined. * * When FSG_NO_DEVICE_STRINGS is defined FSG_STRING_MANUFACTURER, * FSG_STRING_PRODUCT, FSG_STRING_SERIAL and FSG_STRING_CONFIG are not * defined (as well as corresponding entries in string tables are * missing) and FSG_STRING_INTERFACE has value of zero. * * When FSG_NO_OTG is defined fsg_otg_desc won't be defined. */ /* * When FSG_BUFFHD_STATIC_BUFFER is defined when this file is included * the fsg_buffhd structure's buf field will be an array of FSG_BUFLEN * characters rather then a pointer to void. */ /* * When USB_GADGET_DEBUG_FILES is defined the module param num_buffers * sets the number of pipeline buffers (length of the fsg_buffhd array). * The valid range of num_buffers is: num >= 2 && num <= 4. */ #include #include #include /* * Thanks to NetChip Technologies for donating this product ID. * * DO NOT REUSE THESE IDs with any other driver!! Ever!! * Instead: allocate your own, using normal USB-IF procedures. */ #define FSG_VENDOR_ID 0x0525 /* NetChip */ #define FSG_PRODUCT_ID 0xa4a5 /* Linux-USB File-backed Storage Gadget */ /*-------------------------------------------------------------------------*/ #ifndef DEBUG #undef VERBOSE_DEBUG #undef DUMP_MSGS #endif /* !DEBUG */ #ifdef VERBOSE_DEBUG #define VLDBG LDBG #else #define VLDBG(lun, fmt, args...) do { } while (0) #endif /* VERBOSE_DEBUG */ #define LDBG(lun, fmt, args...) dev_dbg (&(lun)->dev, fmt, ## args) #define LERROR(lun, fmt, args...) dev_err (&(lun)->dev, fmt, ## args) #define LWARN(lun, fmt, args...) dev_warn(&(lun)->dev, fmt, ## args) #define LINFO(lun, fmt, args...) dev_info(&(lun)->dev, fmt, ## args) /* * Keep those macros in sync with those in * include/linux/usb/composite.h or else GCC will complain. If they * are identical (the same names of arguments, white spaces in the * same places) GCC will allow redefinition otherwise (even if some * white space is removed or added) warning will be issued. * * Those macros are needed here because File Storage Gadget does not * include the composite.h header. For composite gadgets those macros * are redundant since composite.h is included any way. * * One could check whether those macros are already defined (which * would indicate composite.h had been included) or not (which would * indicate we were in FSG) but this is not done because a warning is * desired if definitions here differ from the ones in composite.h. * * We want the definitions to match and be the same in File Storage * Gadget as well as Mass Storage Function (and so composite gadgets * using MSF). If someone changes them in composite.h it will produce * a warning in this file when building MSF. */ #define DBG(d, fmt, args...) dev_dbg(&(d)->gadget->dev , fmt , ## args) #define VDBG(d, fmt, args...) dev_vdbg(&(d)->gadget->dev , fmt , ## args) #define ERROR(d, fmt, args...) dev_err(&(d)->gadget->dev , fmt , ## args) #define WARNING(d, fmt, args...) dev_warn(&(d)->gadget->dev , fmt , ## args) #define INFO(d, fmt, args...) dev_info(&(d)->gadget->dev , fmt , ## args) #ifdef DUMP_MSGS # define dump_msg(fsg, /* const char * */ label, \ /* const u8 * */ buf, /* unsigned */ length) do { \ if (length < 512) { \ DBG(fsg, "%s, length %u:\n", label, length); \ print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_OFFSET, \ 16, 1, buf, length, 0); \ } \ } while (0) # define dump_cdb(fsg) do { } while (0) #else # define dump_msg(fsg, /* const char * */ label, \ /* const u8 * */ buf, /* unsigned */ length) do { } while (0) # ifdef VERBOSE_DEBUG # define dump_cdb(fsg) \ print_hex_dump(KERN_DEBUG, "SCSI CDB: ", DUMP_PREFIX_NONE, \ 16, 1, (fsg)->cmnd, (fsg)->cmnd_size, 0) \ # else # define dump_cdb(fsg) do { } while (0) # endif /* VERBOSE_DEBUG */ #endif /* DUMP_MSGS */ /*-------------------------------------------------------------------------*/ /* Bulk-only data structures */ /* Command Block Wrapper */ struct fsg_bulk_cb_wrap { __le32 Signature; /* Contains 'USBC' */ u32 Tag; /* Unique per command id */ __le32 DataTransferLength; /* Size of the data */ u8 Flags; /* Direction in bit 7 */ u8 Lun; /* LUN (normally 0) */ u8 Length; /* Of the CDB, <= MAX_COMMAND_SIZE */ u8 CDB[16]; /* Command Data Block */ }; #define USB_BULK_CB_WRAP_LEN 31 #define USB_BULK_CB_SIG 0x43425355 /* Spells out USBC */ #define USB_BULK_IN_FLAG 0x80 /* Command Status Wrapper */ struct bulk_cs_wrap { __le32 Signature; /* Should = 'USBS' */ u32 Tag; /* Same as original command */ __le32 Residue; /* Amount not transferred */ u8 Status; /* See below */ }; #define USB_BULK_CS_WRAP_LEN 13 #define USB_BULK_CS_SIG 0x53425355 /* Spells out 'USBS' */ #define USB_STATUS_PASS 0 #define USB_STATUS_FAIL 1 #define USB_STATUS_PHASE_ERROR 2 /* Bulk-only class specific requests */ #define USB_BULK_RESET_REQUEST 0xff #define USB_BULK_GET_MAX_LUN_REQUEST 0xfe /* CBI Interrupt data structure */ struct interrupt_data { u8 bType; u8 bValue; }; #define CBI_INTERRUPT_DATA_LEN 2 /* CBI Accept Device-Specific Command request */ #define USB_CBI_ADSC_REQUEST 0x00 /* Length of a SCSI Command Data Block */ #define MAX_COMMAND_SIZE 16 /* SCSI Sense Key/Additional Sense Code/ASC Qualifier values */ #define SS_NO_SENSE 0 #define SS_COMMUNICATION_FAILURE 0x040800 #define SS_INVALID_COMMAND 0x052000 #define SS_INVALID_FIELD_IN_CDB 0x052400 #define SS_LOGICAL_BLOCK_ADDRESS_OUT_OF_RANGE 0x052100 #define SS_LOGICAL_UNIT_NOT_SUPPORTED 0x052500 #define SS_MEDIUM_NOT_PRESENT 0x023a00 #define SS_MEDIUM_REMOVAL_PREVENTED 0x055302 #define SS_NOT_READY_TO_READY_TRANSITION 0x062800 #define SS_RESET_OCCURRED 0x062900 #define SS_SAVING_PARAMETERS_NOT_SUPPORTED 0x053900 #define SS_UNRECOVERED_READ_ERROR 0x031100 #define SS_WRITE_ERROR 0x030c02 #define SS_WRITE_PROTECTED 0x072700 #define SK(x) ((u8) ((x) >> 16)) /* Sense Key byte, etc. */ #define ASC(x) ((u8) ((x) >> 8)) #define ASCQ(x) ((u8) (x)) /*-------------------------------------------------------------------------*/ struct fsg_lun { struct file *filp; loff_t file_length; loff_t num_sectors; unsigned int initially_ro:1; unsigned int ro:1; unsigned int removable:1; unsigned int cdrom:1; unsigned int prevent_medium_removal:1; unsigned int registered:1; unsigned int info_valid:1; unsigned int nofua:1; u32 sense_data; u32 sense_data_info; u32 unit_attention_data; unsigned int blkbits; /* Bits of logical block size of bound block device */ unsigned int blksize; /* logical block size of bound block device */ struct device dev; }; #define fsg_lun_is_open(curlun) ((curlun)->filp != NULL) static struct fsg_lun *fsg_lun_from_dev(struct device *dev) { return container_of(dev, struct fsg_lun, dev); } /* Big enough to hold our biggest descriptor */ #define EP0_BUFSIZE 256 #define DELAYED_STATUS (EP0_BUFSIZE + 999) /* An impossibly large value */ #ifdef CONFIG_USB_GADGET_DEBUG_FILES static unsigned int fsg_num_buffers = CONFIG_USB_GADGET_STORAGE_NUM_BUFFERS; module_param_named(num_buffers, fsg_num_buffers, uint, S_IRUGO); MODULE_PARM_DESC(num_buffers, "Number of pipeline buffers"); #else /* * Number of buffers we will use. * 2 is usually enough for good buffering pipeline */ #define fsg_num_buffers CONFIG_USB_GADGET_STORAGE_NUM_BUFFERS #endif /* CONFIG_USB_DEBUG */ /* check if fsg_num_buffers is within a valid range */ static inline int fsg_num_buffers_validate(void) { if (fsg_num_buffers >= 2 && fsg_num_buffers <= 4) return 0; pr_err("fsg_num_buffers %u is out of range (%d to %d)\n", fsg_num_buffers, 2 ,4); return -EINVAL; } /* Default size of buffer length. */ #define FSG_BUFLEN ((u32)16384) /* Maximal number of LUNs supported in mass storage function */ #define FSG_MAX_LUNS 8 enum fsg_buffer_state { BUF_STATE_EMPTY = 0, BUF_STATE_FULL, BUF_STATE_BUSY }; struct fsg_buffhd { #ifdef FSG_BUFFHD_STATIC_BUFFER char buf[FSG_BUFLEN]; #else void *buf; #endif enum fsg_buffer_state state; struct fsg_buffhd *next; /* * The NetChip 2280 is faster, and handles some protocol faults * better, if we don't submit any short bulk-out read requests. * So we will record the intended request length here. */ unsigned int bulk_out_intended_length; struct usb_request *inreq; int inreq_busy; struct usb_request *outreq; int outreq_busy; }; enum fsg_state { /* This one isn't used anywhere */ FSG_STATE_COMMAND_PHASE = -10, FSG_STATE_DATA_PHASE, FSG_STATE_STATUS_PHASE, FSG_STATE_IDLE = 0, FSG_STATE_ABORT_BULK_OUT, FSG_STATE_RESET, FSG_STATE_INTERFACE_CHANGE, FSG_STATE_CONFIG_CHANGE, FSG_STATE_DISCONNECT, FSG_STATE_EXIT, FSG_STATE_TERMINATED }; enum data_direction { DATA_DIR_UNKNOWN = 0, DATA_DIR_FROM_HOST, DATA_DIR_TO_HOST, DATA_DIR_NONE }; /*-------------------------------------------------------------------------*/ static inline u32 get_unaligned_be24(u8 *buf) { return 0xffffff & (u32) get_unaligned_be32(buf - 1); } /*-------------------------------------------------------------------------*/ enum { #ifndef FSG_NO_DEVICE_STRINGS FSG_STRING_MANUFACTURER = 1, FSG_STRING_PRODUCT, FSG_STRING_SERIAL, FSG_STRING_CONFIG, #endif FSG_STRING_INTERFACE }; #ifndef FSG_NO_OTG static struct usb_otg_descriptor fsg_otg_desc = { .bLength = sizeof fsg_otg_desc, .bDescriptorType = USB_DT_OTG, .bmAttributes = USB_OTG_SRP, }; #endif /* There is only one interface. */ static struct usb_interface_descriptor fsg_intf_desc = { .bLength = sizeof fsg_intf_desc, .bDescriptorType = USB_DT_INTERFACE, .bNumEndpoints = 2, /* Adjusted during fsg_bind() */ .bInterfaceClass = USB_CLASS_MASS_STORAGE, .bInterfaceSubClass = USB_SC_SCSI, /* Adjusted during fsg_bind() */ .bInterfaceProtocol = USB_PR_BULK, /* Adjusted during fsg_bind() */ .iInterface = FSG_STRING_INTERFACE, }; /* * Three full-speed endpoint descriptors: bulk-in, bulk-out, and * interrupt-in. */ static struct usb_endpoint_descriptor fsg_fs_bulk_in_desc = { .bLength = USB_DT_ENDPOINT_SIZE, .bDescriptorType = USB_DT_ENDPOINT, .bEndpointAddress = USB_DIR_IN, .bmAttributes = USB_ENDPOINT_XFER_BULK, /* wMaxPacketSize set by autoconfiguration */ }; static struct usb_endpoint_descriptor fsg_fs_bulk_out_desc = { .bLength = USB_DT_ENDPOINT_SIZE, .bDescriptorType = USB_DT_ENDPOINT, .bEndpointAddress = USB_DIR_OUT, .bmAttributes = USB_ENDPOINT_XFER_BULK, /* wMaxPacketSize set by autoconfiguration */ }; #ifndef FSG_NO_INTR_EP static struct usb_endpoint_descriptor fsg_fs_intr_in_desc = { .bLength = USB_DT_ENDPOINT_SIZE, .bDescriptorType = USB_DT_ENDPOINT, .bEndpointAddress = USB_DIR_IN, .bmAttributes = USB_ENDPOINT_XFER_INT, .wMaxPacketSize = cpu_to_le16(2), .bInterval = 32, /* frames -> 32 ms */ }; #ifndef FSG_NO_OTG # define FSG_FS_FUNCTION_PRE_EP_ENTRIES 2 #else # define FSG_FS_FUNCTION_PRE_EP_ENTRIES 1 #endif #endif static struct usb_descriptor_header *fsg_fs_function[] = { #ifndef FSG_NO_OTG (struct usb_descriptor_header *) &fsg_otg_desc, #endif (struct usb_descriptor_header *) &fsg_intf_desc, (struct usb_descriptor_header *) &fsg_fs_bulk_in_desc, (struct usb_descriptor_header *) &fsg_fs_bulk_out_desc, #ifndef FSG_NO_INTR_EP (struct usb_descriptor_header *) &fsg_fs_intr_in_desc, #endif NULL, }; /* * USB 2.0 devices need to expose both high speed and full speed * descriptors, unless they only run at full speed. * * That means alternate endpoint descriptors (bigger packets) * and a "device qualifier" ... plus more construction options * for the configuration descriptor. */ static struct usb_endpoint_descriptor fsg_hs_bulk_in_desc = { .bLength = USB_DT_ENDPOINT_SIZE, .bDescriptorType = USB_DT_ENDPOINT, /* bEndpointAddress copied from fs_bulk_in_desc during fsg_bind() */ .bmAttributes = USB_ENDPOINT_XFER_BULK, .wMaxPacketSize = cpu_to_le16(512), }; static struct usb_endpoint_descriptor fsg_hs_bulk_out_desc = { .bLength = USB_DT_ENDPOINT_SIZE, .bDescriptorType = USB_DT_ENDPOINT, /* bEndpointAddress copied from fs_bulk_out_desc during fsg_bind() */ .bmAttributes = USB_ENDPOINT_XFER_BULK, .wMaxPacketSize = cpu_to_le16(512), .bInterval = 1, /* NAK every 1 uframe */ }; #ifndef FSG_NO_INTR_EP static struct usb_endpoint_descriptor fsg_hs_intr_in_desc = { .bLength = USB_DT_ENDPOINT_SIZE, .bDescriptorType = USB_DT_ENDPOINT, /* bEndpointAddress copied from fs_intr_in_desc during fsg_bind() */ .bmAttributes = USB_ENDPOINT_XFER_INT, .wMaxPacketSize = cpu_to_le16(2), .bInterval = 9, /* 2**(9-1) = 256 uframes -> 32 ms */ }; #ifndef FSG_NO_OTG # define FSG_HS_FUNCTION_PRE_EP_ENTRIES 2 #else # define FSG_HS_FUNCTION_PRE_EP_ENTRIES 1 #endif #endif static struct usb_descriptor_header *fsg_hs_function[] = { #ifndef FSG_NO_OTG (struct usb_descriptor_header *) &fsg_otg_desc, #endif (struct usb_descriptor_header *) &fsg_intf_desc, (struct usb_descriptor_header *) &fsg_hs_bulk_in_desc, (struct usb_descriptor_header *) &fsg_hs_bulk_out_desc, #ifndef FSG_NO_INTR_EP (struct usb_descriptor_header *) &fsg_hs_intr_in_desc, #endif NULL, }; /* Maxpacket and other transfer characteristics vary by speed. */ static __maybe_unused struct usb_endpoint_descriptor * fsg_ep_desc(struct usb_gadget *g, struct usb_endpoint_descriptor *fs, struct usb_endpoint_descriptor *hs) { if (gadget_is_dualspeed(g) && g->speed == USB_SPEED_HIGH) return hs; return fs; } /* Static strings, in UTF-8 (for simplicity we use only ASCII characters) */ static struct usb_string fsg_strings[] = { #ifndef FSG_NO_DEVICE_STRINGS {FSG_STRING_MANUFACTURER, fsg_string_manufacturer}, {FSG_STRING_PRODUCT, fsg_string_product}, {FSG_STRING_SERIAL, ""}, {FSG_STRING_CONFIG, fsg_string_config}, #endif {FSG_STRING_INTERFACE, fsg_string_interface}, {} }; static struct usb_gadget_strings fsg_stringtab = { .language = 0x0409, /* en-us */ .strings = fsg_strings, }; /*-------------------------------------------------------------------------*/ /* * If the next two routines are called while the gadget is registered, * the caller must own fsg->filesem for writing. */ static int fsg_lun_open(struct fsg_lun *curlun, const char *filename) { int ro; struct file *filp = NULL; int rc = -EINVAL; struct inode *inode = NULL; loff_t size; loff_t num_sectors; loff_t min_sectors; /* R/W if we can, R/O if we must */ ro = curlun->initially_ro; if (!ro) { filp = filp_open(filename, O_RDWR | O_LARGEFILE, 0); if (PTR_ERR(filp) == -EROFS || PTR_ERR(filp) == -EACCES) ro = 1; } if (ro) filp = filp_open(filename, O_RDONLY | O_LARGEFILE, 0); if (IS_ERR(filp)) { LINFO(curlun, "unable to open backing file: %s\n", filename); return PTR_ERR(filp); } if (!(filp->f_mode & FMODE_WRITE)) ro = 1; if (filp->f_path.dentry) inode = filp->f_path.dentry->d_inode; if (!inode || (!S_ISREG(inode->i_mode) && !S_ISBLK(inode->i_mode))) { LINFO(curlun, "invalid file type: %s\n", filename); goto out; } /* * If we can't read the file, it's no good. * If we can't write the file, use it read-only. */ if (!filp->f_op || !(filp->f_op->read || filp->f_op->aio_read)) { LINFO(curlun, "file not readable: %s\n", filename); goto out; } if (!(filp->f_op->write || filp->f_op->aio_write)) ro = 1; size = i_size_read(inode->i_mapping->host); if (size < 0) { LINFO(curlun, "unable to find file size: %s\n", filename); rc = (int) size; goto out; } if (curlun->cdrom) { curlun->blksize = 2048; curlun->blkbits = 11; } else if (inode->i_bdev) { curlun->blksize = bdev_logical_block_size(inode->i_bdev); curlun->blkbits = blksize_bits(curlun->blksize); } else { curlun->blksize = 512; curlun->blkbits = 9; } num_sectors = size >> curlun->blkbits; /* File size in logic-block-size blocks */ min_sectors = 1; if (curlun->cdrom) { min_sectors = 300; /* Smallest track is 300 frames */ if (num_sectors >= 256*60*75) { num_sectors = 256*60*75 - 1; LINFO(curlun, "file too big: %s\n", filename); LINFO(curlun, "using only first %d blocks\n", (int) num_sectors); } } if (num_sectors < min_sectors) { LINFO(curlun, "file too small: %s\n", filename); rc = -ETOOSMALL; goto out; } get_file(filp); curlun->ro = ro; curlun->filp = filp; curlun->file_length = size; curlun->num_sectors = num_sectors; LDBG(curlun, "open backing file: %s\n", filename); rc = 0; out: filp_close(filp, current->files); return rc; } static void fsg_lun_close(struct fsg_lun *curlun) { if (curlun->filp) { LDBG(curlun, "close backing file\n"); fput(curlun->filp); curlun->filp = NULL; } } /*-------------------------------------------------------------------------*/ /* * Sync the file data, don't bother with the metadata. * This code was copied from fs/buffer.c:sys_fdatasync(). */ static int fsg_lun_fsync_sub(struct fsg_lun *curlun) { struct file *filp = curlun->filp; if (curlun->ro || !filp) return 0; return vfs_fsync(filp, 1); } static void store_cdrom_address(u8 *dest, int msf, u32 addr) { if (msf) { /* Convert to Minutes-Seconds-Frames */ addr >>= 2; /* Convert to 2048-byte frames */ addr += 2*75; /* Lead-in occupies 2 seconds */ dest[3] = addr % 75; /* Frames */ addr /= 75; dest[2] = addr % 60; /* Seconds */ addr /= 60; dest[1] = addr; /* Minutes */ dest[0] = 0; /* Reserved */ } else { /* Absolute sector */ put_unaligned_be32(addr, dest); } } /*-------------------------------------------------------------------------*/ static ssize_t fsg_show_ro(struct device *dev, struct device_attribute *attr, char *buf) { struct fsg_lun *curlun = fsg_lun_from_dev(dev); return sprintf(buf, "%d\n", fsg_lun_is_open(curlun) ? curlun->ro : curlun->initially_ro); } static ssize_t fsg_show_nofua(struct device *dev, struct device_attribute *attr, char *buf) { struct fsg_lun *curlun = fsg_lun_from_dev(dev); return sprintf(buf, "%u\n", curlun->nofua); } static ssize_t fsg_show_file(struct device *dev, struct device_attribute *attr, char *buf) { struct fsg_lun *curlun = fsg_lun_from_dev(dev); struct rw_semaphore *filesem = dev_get_drvdata(dev); char *p; ssize_t rc; down_read(filesem); if (fsg_lun_is_open(curlun)) { /* Get the complete pathname */ p = d_path(&curlun->filp->f_path, buf, PAGE_SIZE - 1); if (IS_ERR(p)) rc = PTR_ERR(p); else { rc = strlen(p); memmove(buf, p, rc); buf[rc] = '\n'; /* Add a newline */ buf[++rc] = 0; } } else { /* No file, return 0 bytes */ *buf = 0; rc = 0; } up_read(filesem); return rc; } static ssize_t fsg_store_ro(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) { ssize_t rc; struct fsg_lun *curlun = fsg_lun_from_dev(dev); struct rw_semaphore *filesem = dev_get_drvdata(dev); unsigned ro; rc = kstrtouint(buf, 2, &ro); if (rc) return rc; /* * Allow the write-enable status to change only while the * backing file is closed. */ down_read(filesem); if (fsg_lun_is_open(curlun)) { LDBG(curlun, "read-only status change prevented\n"); rc = -EBUSY; } else { curlun->ro = ro; curlun->initially_ro = ro; LDBG(curlun, "read-only status set to %d\n", curlun->ro); rc = count; } up_read(filesem); return rc; } static ssize_t fsg_store_nofua(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) { struct fsg_lun *curlun = fsg_lun_from_dev(dev); unsigned nofua; int ret; ret = kstrtouint(buf, 2, &nofua); if (ret) return ret; /* Sync data when switching from async mode to sync */ if (!nofua && curlun->nofua) fsg_lun_fsync_sub(curlun); curlun->nofua = nofua; return count; } static ssize_t fsg_store_file(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) { struct fsg_lun *curlun = fsg_lun_from_dev(dev); struct rw_semaphore *filesem = dev_get_drvdata(dev); int rc = 0; if (curlun->prevent_medium_removal && fsg_lun_is_open(curlun)) { LDBG(curlun, "eject attempt prevented\n"); return -EBUSY; /* "Door is locked" */ } /* Remove a trailing newline */ if (count > 0 && buf[count-1] == '\n') ((char *) buf)[count-1] = 0; /* Ugh! */ /* Eject current medium */ down_write(filesem); if (fsg_lun_is_open(curlun)) { fsg_lun_close(curlun); curlun->unit_attention_data = SS_MEDIUM_NOT_PRESENT; } /* Load new medium */ if (count > 0 && buf[0]) { rc = fsg_lun_open(curlun, buf); if (rc == 0) curlun->unit_attention_data = SS_NOT_READY_TO_READY_TRANSITION; } up_write(filesem); return (rc < 0 ? rc : count); }