2BSD/src/ex/expreserve.c
/* Copyright (c) 1979 Regents of the University of California */
#include <stdio.h>
#include <ctype.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/dir.h>
#include <pwd.h>
/*
* Expreserve - preserve a file in /usr/preserve
* Bill Joy UCB November 13, 1977
*
* This routine is very naive - it doesn't remove anything from
* /usr/preserve... this may mean that we will be unable to preserve
* stuff there... the danger in doing anything with /usr/preserve
* is that the clock may be screwed up and we may get confused.
*
* We are called in two ways - first from the editor with no argumentss
* and the standard input open on the temp file. Second with an argument
* to preserve the entire contents of /tmp (root only).
*
* BUG: should do something about preserving Rx... (register contents)
* temporaries.
*/
#define LBLKS 125
#define FNSIZE 128
struct header {
time_t Time; /* Time temp file last updated */
short Uid; /* This users identity */
short Flines; /* Number of lines in file */
char Savedfile[FNSIZE]; /* The current file name */
short Blocks[LBLKS]; /* Blocks where line pointers stashed */
} H;
#ifdef lint
#define ignore(a) Ignore(a)
#define ignorl(a) Ignorl(a)
#else
#define ignore(a) a
#define ignorl(a) a
#endif
struct passwd *getpwuid();
off_t lseek();
FILE *popen();
#define eq(a, b) strcmp(a, b) == 0
main(argc)
int argc;
{
register FILE *tf;
struct direct dirent;
struct stat stbuf;
/*
* If only one argument, then preserve the standard input.
*/
if (argc == 1) {
if (copyout((char *) 0))
exit(1);
exit(0);
}
/*
* If not super user, then can only preserve standard input.
*/
if (getuid()) {
fprintf(stderr, "NOT super user\n");
exit(1);
}
/*
* ... else preserve all the stuff in /tmp, removing
* it as we go.
*/
if (chdir("/tmp") < 0) {
perror("/tmp");
exit(1);
}
tf = fopen(".", "r");
if (tf == NULL) {
perror("/tmp");
exit(1);
}
while (fread((char *) &dirent, sizeof dirent, 1, tf) == 1) {
if (dirent.d_ino == 0)
continue;
/*
* Ex temporaries must begin with Ex;
* we check that the 10th character of the name is null
* so we won't have to worry about non-null terminated names
* later on.
*/
if (dirent.d_name[0] != 'E' || dirent.d_name[1] != 'x' || dirent.d_name[10])
continue;
if (stat(dirent.d_name, &stbuf))
continue;
if ((stbuf.st_mode & S_IFMT) != S_IFREG)
continue;
/*
* Save the bastard.
*/
ignore(copyout(dirent.d_name));
}
exit(0);
}
char pattern[] = "/usr/preserve/Exaa`XXXXX";
/*
* Copy file name into /usr/preserve/...
* If name is (char *) 0, then do the standard input.
* We make some checks on the input to make sure it is
* really an editor temporary, generate a name for the
* file (this is the slowest thing since we must stat
* to find a unique name), and finally copy the file.
*/
copyout(name)
char *name;
{
int i;
static int reenter;
char buf[BUFSIZ];
/*
* The first time we put in the digits of our
* process number at the end of the pattern.
*/
if (reenter == 0) {
mkdigits(pattern);
reenter++;
}
/*
* If a file name was given, make it the standard
* input if possible.
*/
if (name != 0) {
ignore(close(0));
/*
* Need read/write access for arcane reasons
* (see below).
*/
if (open(name, 2) < 0)
return (-1);
}
/*
* Get the header block.
*/
ignorl(lseek(0, 0l, 0));
if (read(0, (char *) &H, sizeof H) != sizeof H) {
format:
if (name == 0)
fprintf(stderr, "Buffer format error\n");
return (-1);
}
/*
* Consistency checsks so we don't copy out garbage.
*/
if (H.Flines < 0) {
#ifdef DEBUG
fprintf(stderr, "Negative number of lines\n");
#endif
goto format;
}
if (H.Blocks[0] != 1 || H.Blocks[1] != 2) {
#ifdef DEBUG
fprintf(stderr, "Blocks %d %d\n", H.Blocks[0], H.Blocks[1]);
#endif
goto format;
}
if (name == 0 && H.Uid != getuid()) {
#ifdef DEBUG
fprintf(stderr, "Wrong user-id\n");
#endif
goto format;
}
if (lseek(0, 0l, 0)) {
#ifdef DEBUG
fprintf(stderr, "Negative number of lines\n");
#endif
goto format;
}
/*
* If no name was assigned to the file, then give it the name
* LOST, by putting this in the header.
*/
if (H.Savedfile[0] == 0) {
strcpy(H.Savedfile, "LOST");
ignore(write(0, (char *) &H, sizeof H));
H.Savedfile[0] = 0;
lseek(0, 0l, 0);
}
/*
* File is good. Get a name and create a file for the copy.
*/
mknext(pattern);
ignore(close(1));
if (creat(pattern, 0600) < 0) {
if (name == 0)
perror(pattern);
return (1);
}
/*
* Make the target be owned by the owner of the file.
*/
ignore(chown(pattern, H.Uid, 0));
/*
* Copy the file.
*/
for (;;) {
i = read(0, buf, BUFSIZ);
if (i < 0) {
if (name)
perror("Buffer read error");
ignore(unlink(pattern));
return (-1);
}
if (i == 0) {
if (name) {
ignore(unlink(name));
notify(H.Uid, H.Savedfile);
}
return (0);
}
if (write(1, buf, i) != i) {
if (name == 0)
perror(pattern);
unlink(pattern);
return (-1);
}
}
}
/*
* Blast the last 5 characters of cp to be the process number.
*/
mkdigits(cp)
char *cp;
{
register int i, j;
for (i = getpid(), j = 5, cp += strlen(cp); j > 0; i /= 10, j--)
*--cp = i % 10 | '0';
}
/*
* Make the name in cp be unique by clobbering up to
* three alphabetic characters into a sequence of the form 'aab', 'aac', etc.
* Mktemp gets weird names too quickly to be useful here.
*/
mknext(cp)
char *cp;
{
char *dcp;
struct stat stb;
dcp = cp + strlen(cp) - 1;
while (isdigit(*dcp))
dcp--;
whoops:
if (dcp[0] == 'z') {
dcp[0] = 'a';
if (dcp[-1] == 'z') {
dcp[-1] = 'a';
if (dcp[-2] == 'z')
fprintf(stderr, "Can't find a name\n");
dcp[-2]++;
} else
dcp[-1]++;
} else
dcp[0]++;
if (stat(cp, &stb) == 0)
goto whoops;
}
/*
* Notify user uid that his file fname has been saved.
*/
notify(uid, fname)
int uid;
char *fname;
{
struct passwd *pp = getpwuid(uid);
register FILE *mf;
char cmd[BUFSIZ];
if (pp == NULL)
return;
sprintf(cmd, "mail %s", pp->pw_name);
mf = popen(cmd, "w");
if (mf == NULL)
return;
setbuf(mf, cmd);
if (fname[0] == 0)
fprintf(mf,
"A copy of an editor buffer of yours was saved when the system went down.\n\
No name was associated with this buffer so it has been named \"LOST\".\n"
);
else
fprintf(mf,
"A copy of an editor buffer of your file \"%s\"\n\
was saved when the system went down.\n",
fname);
fprintf(mf,
"This buffer can be retrieved using the \"recover\" command of the editor.\n\
An easy way to do this is to give the command ``ex -r'' followed by the\n\
name of file you were editing. This works for ``edit'' and ``vi'' also.\n"
);
pclose(mf);
}
/*
* people making love
* never exactly the same
* just like a snowflake
*/
#ifdef lint
Ignore(a)
int a;
{
a = a;
}
Ignorl(a)
long a;
{
a = a;
}
#endif