4005bba437
This removes a race condition when the block driver performs a complete restart after a crash (the new default). If any user of the driver finds out its new endpoint and sends a request to the new driver instance before this instance has had the chance to initialize, then its initialization would clear all IPC state and thereby erroneously cancel the incoming request. Clearing IPC state is only desired upon a stateful restart (where the driver's endpoint is retained). This information is now passed to and used by libblockdriver accordingly.
493 lines
13 KiB
C
493 lines
13 KiB
C
/* Filter driver - top layer - block interface */
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/* This is a filter driver, which lays above disk driver, and forwards
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* messages between disk driver and its callers. The filter can detect
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* corrupted data (toggled by USE_CHECKSUM) and recover it (toggled
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* by USE_MIRROR). These two functions are independent from each other.
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* The mirroring function requires two disks, on separate disk drivers.
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*/
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#include "inc.h"
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#define _POSIX_SOURCE 1
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#include <signal.h>
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/* Global settings. */
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int USE_CHECKSUM = 0; /* enable checksumming */
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int USE_MIRROR = 0; /* enable mirroring */
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int BAD_SUM_ERROR = 1; /* bad checksums are considered a driver error */
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int USE_SUM_LAYOUT = 0; /* use checksumming layout on disk */
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int NR_SUM_SEC = 8; /* number of checksums per checksum sector */
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int SUM_TYPE = ST_CRC; /* use NIL, XOR, CRC, or MD5 */
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int SUM_SIZE = 0; /* size of the stored checksum */
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int NR_RETRIES = 3; /* number of times the request will be retried (N) */
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int NR_RESTARTS = 3; /* number of times a driver will be restarted (M) */
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int DRIVER_TIMEOUT = 5; /* timeout in seconds to declare a driver dead (T) */
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int CHUNK_SIZE = 0; /* driver requests will be vectorized at this size */
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char MAIN_LABEL[LABEL_SIZE] = ""; /* main disk driver label */
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char BACKUP_LABEL[LABEL_SIZE] = ""; /* backup disk driver label */
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int MAIN_MINOR = -1; /* main partition minor nr */
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int BACKUP_MINOR = -1; /* backup partition minor nr */
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PRIVATE struct optset optset_table[] = {
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{ "label0", OPT_STRING, MAIN_LABEL, LABEL_SIZE },
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{ "label1", OPT_STRING, BACKUP_LABEL, LABEL_SIZE },
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{ "minor0", OPT_INT, &MAIN_MINOR, 10 },
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{ "minor1", OPT_INT, &BACKUP_MINOR, 10 },
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{ "sum_sec", OPT_INT, &NR_SUM_SEC, 10 },
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{ "layout", OPT_BOOL, &USE_SUM_LAYOUT, 1 },
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{ "nolayout", OPT_BOOL, &USE_SUM_LAYOUT, 0 },
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{ "sum", OPT_BOOL, &USE_CHECKSUM, 1 },
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{ "nosum", OPT_BOOL, &USE_CHECKSUM, 0 },
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{ "mirror", OPT_BOOL, &USE_MIRROR, 1 },
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{ "nomirror", OPT_BOOL, &USE_MIRROR, 0 },
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{ "nil", OPT_BOOL, &SUM_TYPE, ST_NIL },
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{ "xor", OPT_BOOL, &SUM_TYPE, ST_XOR },
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{ "crc", OPT_BOOL, &SUM_TYPE, ST_CRC },
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{ "md5", OPT_BOOL, &SUM_TYPE, ST_MD5 },
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{ "sumerr", OPT_BOOL, &BAD_SUM_ERROR, 1 },
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{ "nosumerr", OPT_BOOL, &BAD_SUM_ERROR, 0 },
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{ "retries", OPT_INT, &NR_RETRIES, 10 },
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{ "N", OPT_INT, &NR_RETRIES, 10 },
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{ "restarts", OPT_INT, &NR_RESTARTS, 10 },
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{ "M", OPT_INT, &NR_RESTARTS, 10 },
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{ "timeout", OPT_INT, &DRIVER_TIMEOUT, 10 },
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{ "T", OPT_INT, &DRIVER_TIMEOUT, 10 },
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{ "chunk", OPT_INT, &CHUNK_SIZE, 10 },
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{ NULL, 0, NULL, 0 }
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};
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/* Request message. */
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static message m_in;
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static endpoint_t who_e; /* m_source */
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static long req_id; /* BDEV_ID */
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static cp_grant_id_t grant_id; /* BDEV_GRANT */
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/* Data buffers. */
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static char *buf_array, *buffer; /* contiguous buffer */
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/* SEF functions and variables. */
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FORWARD _PROTOTYPE( void sef_local_startup, (void) );
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FORWARD _PROTOTYPE( int sef_cb_init_fresh, (int type, sef_init_info_t *info) );
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FORWARD _PROTOTYPE( void sef_cb_signal_handler, (int signo) );
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/*===========================================================================*
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* carry *
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*===========================================================================*/
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static int carry(size_t size, int flag_rw)
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{
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/* Carry data between caller proc and filter.
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*/
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if (flag_rw == FLT_WRITE)
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return sys_safecopyfrom(who_e, grant_id, 0,
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(vir_bytes) buffer, size, D);
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else
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return sys_safecopyto(who_e, grant_id, 0,
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(vir_bytes) buffer, size, D);
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}
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/*===========================================================================*
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* vcarry *
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*===========================================================================*/
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static int vcarry(int grants, iovec_t *iov, int flag_rw, size_t size)
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{
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/* Carry data between caller proc and filter, through grant-vector.
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*/
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char *bufp;
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int i, r;
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size_t bytes;
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bufp = buffer;
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for(i = 0; i < grants && size > 0; i++) {
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bytes = MIN(size, iov[i].iov_size);
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if (flag_rw == FLT_WRITE)
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r = sys_safecopyfrom(who_e,
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(vir_bytes) iov[i].iov_addr, 0,
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(vir_bytes) bufp, bytes, D);
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else
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r = sys_safecopyto(who_e,
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(vir_bytes) iov[i].iov_addr, 0,
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(vir_bytes) bufp, bytes, D);
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if(r != OK)
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return r;
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bufp += bytes;
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size -= bytes;
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}
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return OK;
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}
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/*===========================================================================*
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* do_rdwt *
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*===========================================================================*/
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static int do_rdwt(int flag_rw)
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{
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size_t size, size_ret;
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u64_t pos;
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int r;
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pos = make64(m_in.BDEV_POS_LO, m_in.BDEV_POS_HI);
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size = m_in.BDEV_COUNT;
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if (rem64u(pos, SECTOR_SIZE) != 0 || size % SECTOR_SIZE != 0) {
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printf("Filter: unaligned request from caller!\n");
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return EINVAL;
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}
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buffer = flt_malloc(size, buf_array, BUF_SIZE);
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if(flag_rw == FLT_WRITE)
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carry(size, flag_rw);
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reset_kills();
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for (;;) {
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size_ret = size;
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r = transfer(pos, buffer, &size_ret, flag_rw);
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if(r != RET_REDO)
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break;
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#if DEBUG
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printf("Filter: transfer yielded RET_REDO, checking drivers\n");
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#endif
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if((r = check_driver(DRIVER_MAIN)) != OK) break;
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if((r = check_driver(DRIVER_BACKUP)) != OK) break;
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}
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if(r == OK && flag_rw == FLT_READ)
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carry(size_ret, flag_rw);
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flt_free(buffer, size, buf_array);
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if (r != OK)
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return r;
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return size_ret;
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}
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/*===========================================================================*
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* do_vrdwt *
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*===========================================================================*/
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static int do_vrdwt(int flag_rw)
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{
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size_t size, size_ret;
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int grants;
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int r, i;
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u64_t pos;
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iovec_t iov_proc[NR_IOREQS];
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/* Extract informations. */
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grants = m_in.BDEV_COUNT;
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if((r = sys_safecopyfrom(who_e, grant_id, 0, (vir_bytes) iov_proc,
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grants * sizeof(iovec_t), D)) != OK) {
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panic("copying in grant vector failed: %d", r);
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}
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pos = make64(m_in.BDEV_POS_LO, m_in.BDEV_POS_HI);
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for(size = 0, i = 0; i < grants; i++)
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size += iov_proc[i].iov_size;
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if (rem64u(pos, SECTOR_SIZE) != 0 || size % SECTOR_SIZE != 0) {
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printf("Filter: unaligned request from caller!\n");
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return EINVAL;
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}
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buffer = flt_malloc(size, buf_array, BUF_SIZE);
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if(flag_rw == FLT_WRITE)
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vcarry(grants, iov_proc, flag_rw, size);
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reset_kills();
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for (;;) {
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size_ret = size;
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r = transfer(pos, buffer, &size_ret, flag_rw);
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if(r != RET_REDO)
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break;
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#if DEBUG
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printf("Filter: transfer yielded RET_REDO, checking drivers\n");
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#endif
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if((r = check_driver(DRIVER_MAIN)) != OK) break;
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if((r = check_driver(DRIVER_BACKUP)) != OK) break;
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}
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if(r != OK) {
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flt_free(buffer, size, buf_array);
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return r;
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}
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if(flag_rw == FLT_READ)
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vcarry(grants, iov_proc, flag_rw, size_ret);
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flt_free(buffer, size, buf_array);
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return size_ret;
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}
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/*===========================================================================*
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* do_ioctl *
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*===========================================================================*/
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static int do_ioctl(message *m)
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{
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struct partition sizepart;
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switch(m->BDEV_REQUEST) {
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case DIOCSETP:
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case DIOCTIMEOUT:
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case DIOCOPENCT:
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/* These do not make sense for us. */
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return EINVAL;
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case DIOCGETP:
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memset(&sizepart, 0, sizeof(sizepart));
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/* The presented disk size is the raw partition size,
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* corrected for space needed for checksums.
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*/
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sizepart.size = convert(get_raw_size());
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if(sys_safecopyto(who_e, (vir_bytes) grant_id, 0,
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(vir_bytes) &sizepart,
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sizeof(struct partition), D) != OK) {
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printf("Filter: DIOCGETP safecopyto failed\n");
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return EIO;
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}
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break;
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default:
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printf("Filter: unknown ioctl request: %d!\n",
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m->BDEV_REQUEST);
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return EINVAL;
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}
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return OK;
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}
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/*===========================================================================*
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* parse_arguments *
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*===========================================================================*/
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static int parse_arguments(int argc, char *argv[])
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{
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if(argc != 2)
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return EINVAL;
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optset_parse(optset_table, argv[1]);
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if (MAIN_LABEL[0] == 0 || MAIN_MINOR < 0 || MAIN_MINOR > 255)
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return EINVAL;
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if (USE_MIRROR && (BACKUP_LABEL[0] == 0 ||
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BACKUP_MINOR < 0 || BACKUP_MINOR > 255))
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return EINVAL;
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/* Checksumming implies a checksum layout. */
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if (USE_CHECKSUM)
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USE_SUM_LAYOUT = 1;
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/* Determine the checksum size for the chosen checksum type. */
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switch (SUM_TYPE) {
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case ST_NIL:
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SUM_SIZE = 4; /* for the sector number */
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break;
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case ST_XOR:
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SUM_SIZE = 16; /* compatibility */
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break;
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case ST_CRC:
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SUM_SIZE = 4;
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break;
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case ST_MD5:
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SUM_SIZE = 16;
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break;
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default:
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return EINVAL;
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}
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if (NR_SUM_SEC <= 0 || SUM_SIZE * NR_SUM_SEC > SECTOR_SIZE)
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return EINVAL;
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#if DEBUG
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printf("Filter starting. Configuration:\n");
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printf(" USE_CHECKSUM : %3s ", USE_CHECKSUM ? "yes" : "no");
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printf(" USE_MIRROR : %3s\n", USE_MIRROR ? "yes" : "no");
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if (USE_CHECKSUM) {
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printf(" BAD_SUM_ERROR : %3s ",
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BAD_SUM_ERROR ? "yes" : "no");
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printf(" NR_SUM_SEC : %3d\n", NR_SUM_SEC);
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printf(" SUM_TYPE : ");
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switch (SUM_TYPE) {
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case ST_NIL: printf("nil"); break;
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case ST_XOR: printf("xor"); break;
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case ST_CRC: printf("crc"); break;
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case ST_MD5: printf("md5"); break;
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}
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printf(" SUM_SIZE : %3d\n", SUM_SIZE);
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}
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else printf(" USE_SUM_LAYOUT : %3s\n", USE_SUM_LAYOUT ? "yes" : "no");
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printf(" N : %3dx M : %3dx T : %3ds\n",
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NR_RETRIES, NR_RESTARTS, DRIVER_TIMEOUT);
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printf(" MAIN_LABEL / MAIN_MINOR : %19s / %d\n",
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MAIN_LABEL, MAIN_MINOR);
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if (USE_MIRROR) {
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printf(" BACKUP_LABEL / BACKUP_MINOR : %15s / %d\n",
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BACKUP_LABEL, BACKUP_MINOR);
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}
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#endif
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/* Convert timeout seconds to ticks. */
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DRIVER_TIMEOUT *= sys_hz();
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return OK;
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}
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/*===========================================================================*
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* main *
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*===========================================================================*/
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int main(int argc, char *argv[])
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{
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message m_out;
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int r, ipc_status;
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size_t size;
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/* SEF local startup. */
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env_setargs(argc, argv);
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sef_local_startup();
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for (;;) {
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/* Wait for request. */
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if(driver_receive(ANY, &m_in, &ipc_status) != OK) {
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panic("driver_receive failed");
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}
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#if DEBUG2
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printf("Filter: got request %d from %d\n",
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m_in.m_type, m_in.m_source);
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#endif
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if(m_in.m_source == DS_PROC_NR && is_ipc_notify(ipc_status)) {
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ds_event();
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continue;
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}
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who_e = m_in.m_source;
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req_id = m_in.BDEV_ID;
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grant_id = m_in.BDEV_GRANT;
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size = 0;
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/* Forword the request message to the drivers. */
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switch(m_in.m_type) {
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case BDEV_OPEN: /* open/close is a noop for filter. */
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case BDEV_CLOSE: r = OK; break;
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case BDEV_READ: r = do_rdwt(FLT_READ); break;
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case BDEV_WRITE: r = do_rdwt(FLT_WRITE); break;
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case BDEV_GATHER: r = do_vrdwt(FLT_READ); break;
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case BDEV_SCATTER: r = do_vrdwt(FLT_WRITE); break;
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case BDEV_IOCTL: r = do_ioctl(&m_in); break;
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default:
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printf("Filter: ignoring unknown request %d from %d\n",
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m_in.m_type, m_in.m_source);
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continue;
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}
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#if DEBUG2
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printf("Filter: replying with code %d\n", r);
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#endif
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/* Send back reply message. */
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m_out.m_type = BDEV_REPLY;
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m_out.BDEV_ID = req_id;
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m_out.BDEV_STATUS = r;
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send(who_e, &m_out);
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}
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return 0;
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}
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/*===========================================================================*
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* sef_local_startup *
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*===========================================================================*/
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PRIVATE void sef_local_startup(void)
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{
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/* Register init callbacks. */
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sef_setcb_init_fresh(sef_cb_init_fresh);
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sef_setcb_init_restart(sef_cb_init_fresh);
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/* No live update support for now. */
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/* Register signal callbacks. */
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sef_setcb_signal_handler(sef_cb_signal_handler);
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/* Let SEF perform startup. */
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sef_startup();
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}
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/*===========================================================================*
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* sef_cb_init_fresh *
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*===========================================================================*/
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PRIVATE int sef_cb_init_fresh(int type, sef_init_info_t *UNUSED(info))
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{
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/* Initialize the filter driver. */
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int r;
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r = parse_arguments(env_argc, env_argv);
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if(r != OK) {
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printf("Filter: wrong argument!\n");
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return 1;
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}
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if ((buf_array = flt_malloc(BUF_SIZE, NULL, 0)) == NULL)
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panic("no memory available");
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sum_init();
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driver_init();
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/* Subscribe to block driver events. */
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r = ds_subscribe("drv\\.blk\\..*", DSF_INITIAL | DSF_OVERWRITE);
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if(r != OK) {
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panic("Filter: can't subscribe to driver events");
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}
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/* Announce we are up! */
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blockdriver_announce(type);
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return(OK);
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}
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/*===========================================================================*
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* sef_cb_signal_handler *
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*===========================================================================*/
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PRIVATE void sef_cb_signal_handler(int signo)
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{
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/* Only check for termination signal, ignore anything else. */
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if (signo != SIGTERM) return;
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/* If so, shut down this driver. */
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#if DEBUG
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printf("Filter: shutdown...\n");
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#endif
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driver_shutdown();
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exit(0);
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}
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