2BSD/src/ex/exrecover.c
/* Copyright (c) 1979 Regents of the University of California */
#include "ex.h"
#include "ex_temp.h"
#include "ex_tty.h"
#undef BUFSIZ
#undef EOF
#undef NULL
#include <stdio.h>
#include <sys/dir.h>
/*
* Ex recovery program
* exrecover dir name
* exrecover -r
*
* This program searches through the specified directory and then
* the directory /usr/preserve looking for an instance of the specified
* file from a crashed editor or a crashed system.
* If this file is found, it is unscrambled and written to
* the standard output.
*
* If this program terminates without a "broken pipe" diagnostic
* (i.e. the editor doesn't die right away) then the buffer we are
* writing from is removed when we finish. This is potentially a mistake
* as there is not enough handshaking to guarantee that the file has actually
* been recovered, but should suffice for most cases.
*/
/*
* For lint's sake...
*/
#ifndef lint
#define ignorl(a) a
#endif
/*
* This directory definition also appears (obviously) in expreserve.c.
* Change both if you change either.
*/
char mydir[] = "/usr/preserve";
/*
* Limit on the number of printed entries
* when an, e.g. ``ex -r'' command is given.
*/
#define NENTRY 50
char *ctime();
char nb[BUFSIZ];
int vercnt; /* Count number of versions of file found */
main(argc, argv)
int argc;
char *argv[];
{
register char *cp;
register int b, i;
/*
* Initialize as though the editor had just started.
*/
fendcore = (line *) sbrk(0);
dot = zero = dol = fendcore;
one = zero + 1;
endcore = fendcore - 2;
iblock = oblock = -1;
/*
* If given only a -r argument, then list the saved files.
*/
if (argc == 2 && eq(argv[1], "-r")) {
listfiles(mydir);
exit(0);
}
if (argc != 3)
error(" Wrong number of arguments to exrecover", 0);
CP(file, argv[2]);
/*
* Search for this file.
*/
findtmp(argv[1]);
/*
* Got (one of the versions of) it, write it back to the editor.
*/
cp = ctime(&H.Time);
cp[19] = 0;
fprintf(stderr, " [Dated: %s", cp);
fprintf(stderr, vercnt > 1 ? ", newest of %d saved]" : "]", vercnt);
H.Flines++;
/*
* Allocate space for the line pointers from the temp file.
*/
if ((int) sbrk((int) (H.Flines * sizeof (line))) == -1)
/*
* Good grief.
*/
error(" Not enough core for lines", 0);
#ifdef DEBUG
fprintf(stderr, "%d lines\n", H.Flines);
#endif
/*
* Now go get the blocks of seek pointers which are scattered
* throughout the temp file, reconstructing the incore
* line pointers at point of crash.
*/
b = 0;
while (H.Flines > 0) {
ignorl(lseek(tfile, (long) blocks[b] * BUFSIZ, 0));
i = H.Flines < BUFSIZ / sizeof (line) ?
H.Flines * sizeof (line) : BUFSIZ;
if (read(tfile, (char *) dot, i) != i) {
perror(nb);
exit(1);
}
dot += i / sizeof (line);
H.Flines -= i / sizeof (line);
b++;
}
dot--; dol = dot;
/*
* Sigh... due to sandbagging some lines may really not be there.
* Find and discard such. This shouldn't happen much.
*/
scrapbad();
/*
* Now if there were any lines in the recovered file
* write them to the standard output.
*/
if (dol > zero) {
addr1 = one; addr2 = dol; io = 1;
putfile();
}
/*
* Trash the saved buffer.
* Hopefully the system won't crash before the editor
* syncs the new recovered buffer; i.e. for an instant here
* you may lose if the system crashes because this file
* is gone, but the editor hasn't completed reading the recovered
* file from the pipe from us to it.
*
* This doesn't work if we are coming from an non-absolute path
* name since we may have chdir'ed but what the hay, noone really
* ever edits with temporaries in "." anyways.
*/
if (nb[0] == '/')
ignore(unlink(nb));
/*
* Adieu.
*/
exit(0);
}
/*
* Print an error message (notably not in error
* message file). If terminal is in RAW mode, then
* we should be writing output for "vi", so don't print
* a newline which would screw up the screen.
*/
/*VARARGS2*/
error(str, inf)
char *str;
int inf;
{
fprintf(stderr, str, inf);
gtty(2, &tty);
if ((tty.sg_flags & RAW) == 0)
fprintf(stderr, "\n");
exit(1);
}
/*
* Here we save the information about files, when
* you ask us what files we have saved for you.
* We buffer file name, number of lines, and the time
* at which the file was saved.
*/
struct svfile {
char sf_name[FNSIZE + 1];
int sf_lines;
char sf_entry[DIRSIZ + 1];
time_t sf_time;
};
listfiles(dirname)
char *dirname;
{
register FILE *dir;
struct direct dirent;
int ecount, qucmp();
register int f;
char *cp;
struct svfile *fp, svbuf[NENTRY];
/*
* Open /usr/preserve, and go there to make things quick.
*/
dir = fopen(dirname, "r");
if (dir == NULL) {
perror(dirname);
return;
}
if (chdir(dirname) < 0) {
perror(dirname);
return;
}
/*
* Look at the candidate files in /usr/preserve.
*/
fp = &svbuf[0];
ecount = 0;
while (fread((char *) &dirent, sizeof dirent, 1, dir) == 1) {
if (dirent.d_ino == 0)
continue;
if (dirent.d_name[0] != 'E')
continue;
#ifdef DEBUG
fprintf(stderr, "considering %s\n", dirent.d_name);
#endif
/*
* Name begins with E; open it and
* make sure the uid in the header is our uid.
* If not, then don't bother with this file, it can't
* be ours.
*/
f = open(dirent.d_name, 0);
if (f < 0) {
#ifdef DEBUG
fprintf(stderr, "open failed\n");
#endif
continue;
}
if (read(f, (char *) &H, sizeof H) != sizeof H) {
#ifdef DEBUG
fprintf(stderr, "culdnt read hedr\n");
#endif
ignore(close(f));
continue;
}
ignore(close(f));
if (getuid() != H.Uid) {
#ifdef DEBUG
fprintf(stderr, "uid wrong\n");
#endif
continue;
}
/*
* Saved the day!
*/
enter(fp++, dirent.d_name, ecount);
ecount++;
#ifdef DEBUG
fprintf(stderr, "entered file %s\n", dirent.d_name);
#endif
}
ignore(fclose(dir));
/*
* If any files were saved, then sort them and print
* them out.
*/
if (ecount == 0) {
fprintf(stderr, "No files saved.\n");
return;
}
qsort(&svbuf[0], ecount, sizeof svbuf[0], qucmp);
for (fp = &svbuf[0]; fp < &svbuf[ecount]; fp++) {
cp = ctime(&fp->sf_time);
cp[10] = 0;
fprintf(stderr, "On %s at ", cp);
cp[16] = 0;
fprintf(stderr, &cp[11]);
fprintf(stderr, " saved %d lines of file \"%s\"\n",
fp->sf_lines, fp->sf_name);
}
}
/*
* Enter a new file into the saved file information.
*/
enter(fp, fname, count)
struct svfile *fp;
char *fname;
{
register char *cp, *cp2;
register struct svfile *f, *fl;
time_t curtime, itol();
f = 0;
if (count >= NENTRY) {
/*
* My god, a huge number of saved files.
* Would you work on a system that crashed this
* often? Hope not. So lets trash the oldest
* as the most useless.
*
* (I wonder if this code has ever run?)
*/
fl = fp - count + NENTRY - 1;
curtime = fl->sf_time;
for (f = fl; --f > fp-count; )
if (f->sf_time < curtime)
curtime = f->sf_time;
for (f = fl; --f > fp-count; )
if (f->sf_time == curtime)
break;
fp = f;
}
/*
* Gotcha.
*/
fp->sf_time = H.Time;
fp->sf_lines = H.Flines;
for (cp2 = fp->sf_name, cp = savedfile; *cp;)
*cp2++ = *cp++;
for (cp2 = fp->sf_entry, cp = fname; *cp && cp-fname < 14;)
*cp2++ = *cp++;
*cp2++ = 0;
}
/*
* Do the qsort compare to sort the entries first by file name,
* then by modify time.
*/
qucmp(p1, p2)
struct svfile *p1, *p2;
{
register int t;
if (t = strcmp(p1->sf_name, p2->sf_name))
return(t);
if (p1->sf_time > p2->sf_time)
return(-1);
return(p1->sf_time < p2->sf_time);
}
/*
* Scratch for search.
*/
char bestnb[BUFSIZ]; /* Name of the best one */
long besttime; /* Time at which the best file was saved */
int bestfd; /* Keep best file open so it dont vanish */
/*
* Look for a file, both in the users directory option value
* (i.e. usually /tmp) and in /usr/preserve.
* Want to find the newest so we search on and on.
*/
findtmp(dir)
char *dir;
{
/*
* No name or file so far.
*/
bestnb[0] = 0;
bestfd = -1;
/*
* Search /usr/preserve and, if we can get there, /tmp
* (actually the users "directory" option).
*/
searchdir(dir);
if (chdir(mydir) == 0)
searchdir(mydir);
if (bestfd != -1) {
/*
* Gotcha.
* Put the file (which is already open) in the file
* used by the temp file routines, and save its
* name for later unlinking.
*/
tfile = bestfd;
CP(nb, bestnb);
ignorl(lseek(tfile, 0l, 0));
/*
* Gotta be able to read the header or fall through
* to lossage.
*/
if (read(tfile, (char *) &H, sizeof H) == sizeof H)
return;
}
/*
* Extreme lossage...
*/
error(" File not found", 0);
}
/*
* Search for the file in directory dirname.
*
* Don't chdir here, because the users directory
* may be ".", and we would move away before we searched it.
* Note that we actually chdir elsewhere (because it is too slow
* to look around in /usr/preserve without chdir'ing there) so we
* can't win, because we don't know the name of '.' and if the path
* name of the file we want to unlink is relative, rather than absolute
* we won't be able to find it again.
*/
searchdir(dirname)
char *dirname;
{
struct direct dirent;
register FILE *dir;
char dbuf[BUFSIZ];
dir = fopen(dirname, "r");
if (dir == NULL)
return;
setbuf(dir, dbuf);
while (fread((char *) &dirent, sizeof dirent, 1, dir) == 1) {
if (dirent.d_ino == 0)
continue;
if (dirent.d_name[0] != 'E' || dirent.d_name[DIRSIZ - 1] != 0)
continue;
/*
* Got a file in the directory starting with E...
* Save a consed up name for the file to unlink
* later, and check that this is really a file
* we are looking for.
*/
ignore(strcat(strcat(strcpy(nb, dirname), "/"), dirent.d_name));
if (yeah(nb)) {
/*
* Well, it is the file we are looking for.
* Is it more recent than any version we found before?
*/
if (H.Time > besttime) {
/*
* A winner.
*/
ignore(close(bestfd));
bestfd = dup(tfile);
besttime = H.Time;
CP(bestnb, nb);
}
/*
* Count versions so user can be told there are
* ``yet more pages to be turned''.
*/
vercnt++;
}
ignore(close(tfile));
}
ignore(fclose(dir));
}
/*
* Given a candidate file to be recovered, see
* if its really an editor temporary and of this
* user and the file specified.
*/
yeah(name)
char *name;
{
tfile = open(name, 2);
if (tfile < 0)
return (0);
if (read(tfile, (char *) &H, sizeof H) != sizeof H) {
nope:
ignore(close(tfile));
return (0);
}
if (!eq(savedfile, file))
goto nope;
if (getuid() != H.Uid)
goto nope;
/*
* This is old and stupid code, which
* puts a word LOST in the header block, so that lost lines
* can be made to point at it.
*/
ignorl(lseek(tfile, 504l, 0));
ignore(write(tfile, "LOST", 5));
return (1);
}
preserve()
{
}
/*
* Find the true end of the scratch file, and ``LOSE''
* lines which point into thin air. This lossage occurs
* due to the sandbagging of i/o which can cause blocks to
* be written in a non-obvious order, different from the order
* in which the editor tried to write them.
*
* Lines which are lost are replaced with the text LOST so
* they are easy to find. We work hard at pretty formatting here
* as lines tend to be lost in blocks.
*
* This only seems to happen on very heavily loaded systems, and
* not very often.
*/
scrapbad()
{
register line *ip;
struct stat stbuf;
off_t size, maxt;
int bno, cnt, bad, was;
char bk[BUFSIZ];
ignore(fstat(tfile, &stbuf));
size = stbuf.st_size;
maxt = (size >> SHFT) | 7;
bno = (maxt >> OFFBTS) & BLKMSK;
#ifdef DEBUG
fprintf(stderr, "size %ld, maxt %o, bno %d\n", size, maxt, bno);
#endif
/*
* Look for a null separating two lines in the temp file;
* if last line was split across blocks, then it is lost
* if the last block is.
*/
while (bno > 0) {
ignorl(lseek(tfile, (long) BUFSIZ * bno, 0));
cnt = read(tfile, (char *) bk, BUFSIZ);
while (cnt > 0)
if (bk[--cnt] == 0)
goto null;
bno--;
}
null:
/*
* Magically calculate the largest valid pointer in the temp file,
* consing it up from the block number and the count.
*/
maxt = ((bno << OFFBTS) | (cnt >> SHFT)) & ~1;
#ifdef DEBUG
fprintf(stderr, "bno %d, cnt %d, maxt %o\n", bno, cnt, maxt);
#endif
/*
* Now cycle through the line pointers,
* trashing the Lusers.
*/
was = bad = 0;
for (ip = one; ip <= dol; ip++)
if (*ip > maxt) {
#ifdef DEBUG
fprintf(stderr, "%d bad, %o > %o\n", ip - zero, *ip, maxt);
#endif
if (was == 0)
was = ip - zero;
*ip = 504 >> SHFT;
} else if (was) {
if (bad == 0)
fprintf(stderr, " [Lost line(s):");
fprintf(stderr, " %d", was);
if ((ip - 1) - zero > was)
fprintf(stderr, "-%d", (ip - 1) - zero);
bad++;
was = 0;
}
if (was != 0) {
if (bad == 0)
fprintf(stderr, " [Lost line(s):");
fprintf(stderr, " %d", was);
if (dol - zero != was)
fprintf(stderr, "-%d", dol - zero);
bad++;
}
if (bad)
fprintf(stderr, "]");
}
/*
* Aw shucks, if we only had a (void) cast.
*/
#ifdef lint
Ignorl(a)
long a;
{
a = a;
}
Ignore(a)
char *a;
{
a = a;
}
Ignorf(a)
int (*a)();
{
a = a;
}
ignorl(a)
long a;
{
a = a;
}
#endif
int cntch, cntln, cntodd, cntnull;
/*
* Following routines stolen mercilessly from ex.
*/
putfile()
{
line *a1;
register char *fp, *lp;
register int nib;
a1 = addr1;
clrstats();
cntln = addr2 - a1 + 1;
if (cntln == 0)
return;
nib = BUFSIZ;
fp = genbuf;
do {
getline(*a1++);
lp = linebuf;
for (;;) {
if (--nib < 0) {
nib = fp - genbuf;
if (write(io, genbuf, nib) != nib)
wrerror();
cntch += nib;
nib = 511;
fp = genbuf;
}
if ((*fp++ = *lp++) == 0) {
fp[-1] = '\n';
break;
}
}
} while (a1 <= addr2);
nib = fp - genbuf;
if (write(io, genbuf, nib) != nib)
wrerror();
cntch += nib;
}
wrerror()
{
syserror();
}
clrstats()
{
ninbuf = 0;
cntch = 0;
cntln = 0;
cntnull = 0;
cntodd = 0;
}
#define READ 0
#define WRITE 1
getline(tl)
line tl;
{
register char *bp, *lp;
register int nl;
lp = linebuf;
bp = getblock(tl, READ);
nl = nleft;
tl &= ~OFFMSK;
while (*lp++ = *bp++)
if (--nl == 0) {
bp = getblock(tl += INCRMT, READ);
nl = nleft;
}
}
int read();
int write();
char *
getblock(atl, iof)
line atl;
int iof;
{
register int bno, off;
bno = (atl >> OFFBTS) & BLKMSK;
off = (atl << SHFT) & LBTMSK;
if (bno >= NMBLKS)
error(" Tmp file too large");
nleft = BUFSIZ - off;
if (bno == iblock) {
ichanged |= iof;
return (ibuff + off);
}
if (bno == oblock)
return (obuff + off);
if (iof == READ) {
if (ichanged)
blkio(iblock, ibuff, write);
ichanged = 0;
iblock = bno;
blkio(bno, ibuff, read);
return (ibuff + off);
}
if (oblock >= 0)
blkio(oblock, obuff, write);
oblock = bno;
return (obuff + off);
}
blkio(b, buf, iofcn)
short b;
char *buf;
int (*iofcn)();
{
lseek(tfile, (long) (unsigned) b * BUFSIZ, 0);
if ((*iofcn)(tfile, buf, BUFSIZ) != 512)
syserror();
}
syserror()
{
extern int sys_nerr;
extern char *sys_errlist[];
dirtcnt = 0;
write(2, " ", 1);
if (errno >= 0 && errno <= sys_nerr)
error(sys_errlist[errno]);
else
error("System error %d", errno);
exit(1);
}