618 lines
14 KiB
C
618 lines
14 KiB
C
/*
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* ecp - copy a file fast (in big blocks), cope with errors, optionally verify.
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*
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* Transfers a block at a time. On error, retries one sector at a time,
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* and reports all errors on the retry.
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* Unlike dd, ecp ignores EOF, since it is sometimes reported on error.
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* Also unlike `dd conv=noerror,sync', ecp doesn't get stuck nor give up.
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*
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* Written by Geoff Collyer, originally to run on RSX-11M(!) in 1979.
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* Later simplified for UNIX and ultimately Plan 9.
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*/
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#include <u.h>
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#include <libc.h>
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#include <ctype.h>
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/* fundamental constants */
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enum {
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No = 0,
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Yes,
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Noseek = 0, /* need not seek, may seek on seekable files */
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Mustseek,
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Enone = 0,
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Eio,
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};
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/* tunable parameters */
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enum {
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Defsectsz = 512, /* default sector size */
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/* 10K is a good size for HP WORM drives */
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Defblksz = 16*1024, /* default block (big-transfer) size */
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Mingoodblks = 3, /* after this many, go back to fast mode */
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};
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#define TTY "/dev/cons" /* plan 9 */
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#define badsect(errno) ((errno) != Enone) /* was last transfer in error? */
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/* disk address (in bytes or sectors), also type of 2nd arg. to seek */
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typedef uvlong Daddr;
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typedef vlong Sdaddr; /* signed disk address */
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typedef long Rdwrfn(int, void *, long); /* plan 9 read or write */
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typedef struct {
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char *name;
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int fd;
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Daddr startsect;
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int fast;
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int seekable;
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ulong maxconerrs; /* maximum consecutive errors */
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ulong conerrs; /* current consecutive errors */
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Daddr congoodblks;
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Daddr harderrs;
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Daddr lasterr; /* sector #s */
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Daddr lastgood;
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} File;
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/* exports */
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char *argv0;
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/* privates */
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static int reblock = No, progress = No, swizzle = No;
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static int reverse = No;
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static ulong sectsz = Defsectsz;
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static ulong blocksize = Defblksz;
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static char *buf, *vfybuf;
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static int blksects;
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/*
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* warning - print best error message possible and clear errno
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*/
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void
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warning(char *s1, char *s2)
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{
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char err[100], msg[256];
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char *np, *ep = msg + sizeof msg - 1;
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errstr(err, sizeof err); /* save error string */
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np = seprint(msg, ep, "%s: ", argv0);
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np = seprint(np, ep, s1, s2);
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errstr(err, sizeof err); /* restore error string */
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seprint(np, ep, ": %r\n");
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fprint(2, "%s", msg);
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}
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int
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eopen(char *file, int mode)
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{
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int fd = open(file, mode);
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if (fd < 0)
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sysfatal("can't open %s: %r", file);
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return fd;
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}
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static int /* boolean */
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confirm(File *src, File *dest)
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{
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int absent, n, tty = eopen(TTY, 2);
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char c, junk;
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Dir *stp;
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if ((stp = dirstat(src->name)) == nil)
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sysfatal("no input file %s: %r", src->name);
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free(stp);
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stp = dirstat(dest->name);
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absent = (stp == nil);
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free(stp);
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fprint(2, "%s: copy %s to %s%s? ", argv0, src->name, dest->name,
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(absent? " (missing)": ""));
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n = read(tty, &c, 1);
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junk = c;
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if (n < 1)
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c = 'n';
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while (n > 0 && junk != '\n')
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n = read(tty, &junk, 1);
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close(tty);
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if (isascii(c) && isupper(c))
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c = tolower(c);
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return c == 'y';
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}
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static char *
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sectid(File *fp, Daddr sect)
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{
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static char sectname[256];
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if (fp->startsect == 0)
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snprint(sectname, sizeof sectname, "%s sector %llud",
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fp->name, sect);
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else
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snprint(sectname, sizeof sectname,
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"%s sector %llud (relative %llud)",
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fp->name, sect + fp->startsect, sect);
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return sectname;
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}
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static void
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io_expl(File *fp, char *rw, Daddr sect) /* explain an i/o error */
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{
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/* print only first 2 bad sectors in a range, if going forward */
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if (reverse || fp->conerrs == 0) {
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char msg[128];
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snprint(msg, sizeof msg, "%s %s", rw, sectid(fp, sect));
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warning("%s", msg);
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} else if (fp->conerrs == 1)
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fprint(2, "%s: ...\n", argv0);
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}
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static void
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repos(File *fp, Daddr sect)
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{
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if (!fp->seekable)
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sysfatal("%s: trying to seek on unseekable file", fp->name);
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if (seek(fp->fd, (sect+fp->startsect)*sectsz, 0) == -1)
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sysfatal("can't seek on %s: %r", fp->name);
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}
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static void
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rewind(File *fp)
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{
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repos(fp, 0);
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}
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/*
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* transfer (many) sectors. reblock input as needed.
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* returns Enone if no failures, others on failure with errstr set.
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*/
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static int
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bio(File *fp, Rdwrfn *rdwr, char *buff, Daddr stsect, int sects, int mustseek)
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{
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int xfered;
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ulong toread, bytes = sects * sectsz;
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static int reblocked = 0;
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if (mustseek) {
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if (!fp->seekable)
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sysfatal("%s: need to seek on unseekable file",
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fp->name);
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repos(fp, stsect);
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}
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if ((long)blocksize != blocksize || (long)bytes != bytes)
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sysfatal("i/o count too big: %lud", bytes);
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werrstr("");
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xfered = (*rdwr)(fp->fd, buff, bytes);
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if (xfered == bytes)
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return Enone; /* did as we asked */
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if (xfered < 0)
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return Eio; /* out-and-out i/o error */
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/*
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* Kernel transferred less than asked. Shouldn't happen;
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* probably indicates disk driver error or trying to
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* transfer past the end of a disk partition. Treat as an
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* I/O error that reads zeros past the point of error,
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* unless reblocking input and this is a read.
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*/
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if (rdwr == write)
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return Eio;
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if (!reblock) {
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memset(buff+xfered, '\0', bytes-xfered);
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return Eio; /* short read */
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}
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/* for pipes that return less than asked */
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if (progress && !reblocked) {
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fprint(2, "%s: reblocking input\n", argv0);
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reblocked++;
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}
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for (toread = bytes - xfered; toread != 0; toread -= xfered) {
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xfered = (*rdwr)(fp->fd, buff+bytes-toread, toread);
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if (xfered <= 0)
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break;
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}
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if (xfered < 0)
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return Eio; /* out-and-out i/o error */
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if (toread != 0) /* early EOF? */
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memset(buff+bytes-toread, '\0', toread);
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return Enone;
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}
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/* called only after a single-sector transfer */
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static int
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toomanyerrs(File *fp, Daddr sect)
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{
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if (sect == fp->lasterr+1)
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fp->conerrs++;
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else
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fp->conerrs = 0;
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fp->lasterr = sect;
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return fp->maxconerrs != 0 && fp->conerrs >= fp->maxconerrs &&
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fp->lastgood == -1;
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}
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static void
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ckendrange(File *fp)
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{
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if (!reverse && fp->conerrs > 0)
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fprint(2, "%s: %lld: ... last bad sector in range\n",
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argv0, fp->lasterr);
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}
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static int
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transfer(File *fp, Rdwrfn *rdwr, char *buff, Daddr stsect, int sects,
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int mustseek)
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{
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int res = bio(fp, rdwr, buff, stsect, sects, mustseek);
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if (badsect(res)) {
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fp->fast = 0; /* read single sectors for a while */
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fp->congoodblks = 0;
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} else
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fp->lastgood = stsect + sects - 1;
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return res;
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}
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/*
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* Read or write many sectors at once.
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* If it fails, retry the individual sectors and report errors.
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*/
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static void
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bigxfer(File *fp, Rdwrfn *rdwr, char *buff, Daddr stsect, int sects,
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int mustseek)
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{
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int i, badsects = 0, wasfast = fp->fast;
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char *rw = (rdwr == read? "read": "write");
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if (fp->fast) {
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if (!badsect(transfer(fp, rdwr, buff, stsect, sects, mustseek)))
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return;
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if (progress)
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fprint(2, "%s: breaking up big transfer on %s error "
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"`%r' on %s\n", argv0, rw, sectid(fp, stsect));
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}
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for (i = 0; i < sects; i++)
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if (badsect(transfer(fp, rdwr, buff+i*sectsz, stsect+i, 1,
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Mustseek))) {
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io_expl(fp, rw, stsect+i);
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badsects++;
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fp->harderrs++;
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if (toomanyerrs(fp, stsect+i))
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sysfatal("more than %lud consecutive I/O errors",
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fp->maxconerrs);
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} else {
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ckendrange(fp);
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fp->conerrs = 0;
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}
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if (badsects == 0) {
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ckendrange(fp);
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fp->conerrs = 0;
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if (wasfast)
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fprint(2, "%s: %s error on big transfer at %s but none "
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"on retries!\n", argv0, rw, sectid(fp, stsect));
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++fp->congoodblks;
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if (fp->congoodblks >= Mingoodblks) {
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fprint(2, "%s: %s: back to big transfers\n", argv0,
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fp->name);
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fp->fast = 1;
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}
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} else
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/*
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* the last sector could have been in error, so the seek pointer
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* may need to be corrected.
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*/
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repos(fp, stsect + sects);
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}
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static void
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vrfyfailed(File *src, File *dest, Daddr stsect)
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{
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char *srcsect = strdup(sectid(src, stsect));
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fprint(2, "%s: verify failed at %s (%s)\n", argv0, srcsect,
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sectid(dest, stsect));
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free(srcsect);
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}
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/*
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* I've seen SCSI read errors that the kernel printed but then didn't
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* report to the program doing the read, so if a big verify fails,
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* break it up and verify each sector separately to isolate the bad sector(s).
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*/
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int /* error count */
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verify(File *src, File *dest, char *buff, char *buft, Daddr stsect,
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int sectors)
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{
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int i, errors = 0;
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for (i = 0; i < sectors; i++)
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if (memcmp(buff + i*sectsz, buft + i*sectsz, sectsz) != 0)
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errors++;
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if (errors == 0)
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return errors; /* normal case */
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if (sectors == 1) {
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vrfyfailed(src, dest, stsect);
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return errors;
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}
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/* re-read and verify each sector individually */
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errors = 0;
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for (i = 0; i < sectors; i++) {
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int thissect = stsect + i;
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if (badsect(bio(src, read, buff, thissect, 1, Mustseek)))
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io_expl(src, "read", thissect);
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if (badsect(bio(dest, read, buft, thissect, 1, Mustseek)))
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io_expl(dest, "write", thissect);
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if (memcmp(buff, buft, sectsz) != 0) {
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vrfyfailed(src, dest, thissect);
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++errors;
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}
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}
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if (errors == 0) {
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char *srcsect = strdup(sectid(src, stsect));
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fprint(2, "%s: verification failed on big read at %s (%s) "
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"but not on retries!\n", argv0, srcsect,
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sectid(dest, stsect));
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free(srcsect);
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}
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/*
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* the last sector of each could have been in error, so the seek
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* pointers may need to be corrected.
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*/
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repos(src, stsect + sectors);
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repos(dest, stsect + sectors);
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return errors;
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}
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/*
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* start is starting sector of proposed transfer;
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* nsects is the total number of sectors being copied;
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* maxxfr is the block size in sectors.
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*/
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int
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sectsleft(Daddr start, Daddr nsects, int maxxfr)
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{
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/* nsects-start is sectors to the end */
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if (start + maxxfr <= nsects - 1)
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return maxxfr;
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else
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return nsects - start;
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}
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enum {
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Rotbits = 3,
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};
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void
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swizzlebits(char *buff, int sects)
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{
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uchar *bp, *endbp;
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endbp = (uchar *)(buff+sects*sectsz);
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for (bp = (uchar *)buff; bp < endbp; bp++)
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*bp = ~(*bp>>Rotbits | *bp<<(8-Rotbits));
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}
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/*
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* copy at most blksects sectors, with error retries.
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* stsect is relative to the start of the copy; 0 is the first sector.
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* to get actual sector numbers, add e.g. dest->startsect.
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*/
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static int
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copysects(File *src, File *dest, Daddr stsect, Daddr nsects, int mustseek)
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{
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int xfrsects = sectsleft(stsect, nsects, blksects);
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if (xfrsects > blksects) {
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fprint(2, "%s: block size of %d is too big.\n", argv0, xfrsects);
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exits("block size too big");
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}
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bigxfer(src, read, buf, stsect, xfrsects, mustseek);
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if (swizzle)
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swizzlebits(buf, xfrsects);
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bigxfer(dest, write, buf, stsect, xfrsects, mustseek);
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/* give a few reassurances at the start, then every 10MB */
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if (progress &&
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(stsect < blksects*10 || stsect%(10*1024*1024/sectsz) == 0))
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fprint(2, "%s: copied%s to relative sector %llud\n", argv0,
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(swizzle? " swizzled": ""), stsect + xfrsects - 1);
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return 0;
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}
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/*
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* verify at most blksects sectors, with error retries.
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* return error count.
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*/
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static int
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vrfysects(File *src, File *dest, Daddr stsect, Daddr nsects, int mustseek)
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{
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int xfrsects = sectsleft(stsect, nsects, blksects);
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if (xfrsects > blksects) {
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fprint(2, "%s: block size of %d is too big.\n", argv0, xfrsects);
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exits("block size too big");
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}
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bigxfer(src, read, buf, stsect, xfrsects, mustseek);
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bigxfer(dest, read, vfybuf, stsect, xfrsects, mustseek);
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return verify(src, dest, buf, vfybuf, stsect, xfrsects);
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}
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static void
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setupfile(File *fp, int mode)
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{
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fp->fd = open(fp->name, mode);
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if (fp->fd < 0)
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sysfatal("can't open %s: %r", fp->name);
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fp->seekable = (seek(fp->fd, 0, 1) >= 0);
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if (fp->startsect != 0)
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rewind(fp);
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}
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static Daddr
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copyfile(File *src, File *dest, Daddr nsects, int plsverify)
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{
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Sdaddr stsect, vererrs = 0;
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Dir *stp;
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setupfile(src, OREAD);
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if ((stp = dirstat(dest->name)) == nil) {
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int fd = create(dest->name, ORDWR, 0666);
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if (fd >= 0)
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close(fd);
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}
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free(stp);
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setupfile(dest, ORDWR);
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if (progress)
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fprint(2, "%s: copying first sectors\n", argv0);
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if (reverse)
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for (stsect = (nsects/blksects)*blksects; stsect >= 0;
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stsect -= blksects)
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vererrs += copysects(src, dest, stsect, nsects, Mustseek);
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else {
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for (stsect = 0; stsect < nsects; stsect += blksects)
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vererrs += copysects(src, dest, stsect, nsects, Noseek);
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ckendrange(src);
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ckendrange(dest);
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}
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/*
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* verification is done as a separate pass rather than immediately after
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* writing, in part to defeat caching in clever disk controllers.
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* we really want to see the bits that hit the disk.
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*/
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if (plsverify) {
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fprint(2, "%s: copy done; verifying...\n", argv0);
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rewind(src);
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rewind(dest);
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for (stsect = 0; stsect < nsects; stsect += blksects) /* forward */
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vererrs += vrfysects(src, dest, stsect, nsects, Noseek);
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if (vererrs <= 0)
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fprint(2, "%s: no", argv0);
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else
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fprint(2, "%s: %llud", argv0, vererrs);
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fprint(2, " error%s during verification\n",
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(vererrs != 1? "s": ""));
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}
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close(src->fd);
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close(dest->fd);
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return vererrs;
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}
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static void
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usage(void)
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{
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fprint(2, "usage: %s [-bcprvZ][-B blocksz][-e errs][-s sectsz]"
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"[-i issect][-o ossect] sectors from to\n", argv0);
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exits("usage");
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}
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|
void
|
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initfile(File *fp)
|
|
{
|
|
memset(fp, 0, sizeof *fp);
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fp->fast = 1;
|
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fp->lasterr = -1;
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|
fp->lastgood = -1;
|
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}
|
|
|
|
void
|
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main(int argc, char **argv)
|
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{
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int errflg = 0, plsconfirm = No, plsverify = No;
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long lval;
|
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File src, dest;
|
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Sdaddr sect;
|
|
|
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initfile(&src);
|
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initfile(&dest);
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ARGBEGIN {
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case 'b':
|
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reblock = Yes;
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|
break;
|
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case 'B':
|
|
lval = atol(EARGF(usage()));
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|
if (lval < 0)
|
|
usage();
|
|
blocksize = lval;
|
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break;
|
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case 'c':
|
|
plsconfirm = Yes;
|
|
break;
|
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case 'e':
|
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lval = atol(EARGF(usage()));
|
|
if (lval < 0)
|
|
usage();
|
|
src.maxconerrs = lval;
|
|
dest.maxconerrs = lval;
|
|
break;
|
|
case 'i':
|
|
sect = atoll(EARGF(usage()));
|
|
if (sect < 0)
|
|
usage();
|
|
src.startsect = sect;
|
|
break;
|
|
case 'o':
|
|
sect = atoll(EARGF(usage()));
|
|
if (sect < 0)
|
|
usage();
|
|
dest.startsect = sect;
|
|
break;
|
|
case 'p':
|
|
progress = Yes;
|
|
break;
|
|
case 'r':
|
|
reverse = Yes;
|
|
break;
|
|
case 's':
|
|
sectsz = atol(EARGF(usage()));
|
|
if (sectsz <= 0 || sectsz % 512 != 0)
|
|
usage();
|
|
break;
|
|
case 'v':
|
|
plsverify = Yes;
|
|
break;
|
|
case 'Z':
|
|
swizzle = Yes;
|
|
break;
|
|
default:
|
|
errflg++;
|
|
break;
|
|
} ARGEND
|
|
if (errflg || argc != 3)
|
|
usage();
|
|
if (blocksize <= 0 || blocksize % sectsz != 0)
|
|
sysfatal("block size not a multiple of sector size");
|
|
|
|
if (!isascii(argv[0][0]) || !isdigit(argv[0][0])) {
|
|
fprint(2, "%s: %s is not numeric\n", argv0, argv[0]);
|
|
exits("non-numeric sector count");
|
|
}
|
|
src.name = argv[1];
|
|
dest.name = argv[2];
|
|
|
|
blksects = blocksize / sectsz;
|
|
if (blksects < 1)
|
|
blksects = 1;
|
|
buf = malloc(blocksize);
|
|
vfybuf = malloc(blocksize);
|
|
if (buf == nil || vfybuf == nil)
|
|
sysfatal("out of memory: %r");
|
|
|
|
if (plsconfirm? confirm(&src, &dest): Yes)
|
|
copyfile(&src, &dest, atoll(argv[0]), plsverify);
|
|
exits(src.harderrs || dest.harderrs? "hard errors": 0);
|
|
}
|