sbase/tar.c
2015-02-16 20:01:33 +01:00

347 lines
6.8 KiB
C

/* See LICENSE file for copyright and license details. */
#include <sys/stat.h>
#include <sys/time.h>
#include <grp.h>
#include <pwd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "util.h"
struct header {
char name[100];
char mode[8];
char uid[8];
char gid[8];
char size[12];
char mtime[12];
char chksum[8];
char type;
char link[100];
char magic[6];
char version[2];
char uname[32];
char gname[32];
char major[8];
char minor[8];
char prefix[155];
};
#define BLKSIZ 512
enum Type {
REG = '0', AREG = '\0', HARDLINK = '1', SYMLINK = '2', CHARDEV = '3',
BLOCKDEV = '4', DIRECTORY = '5', FIFO = '6'
};
static FILE *tarfile;
static ino_t tarinode;
static dev_t tardev;
static int mflag;
static int fflag = 'P';
static char filtermode;
static FILE *
decomp(FILE *fp)
{
pid_t pid;
int fds[2];
if (pipe(fds) < 0)
eprintf("pipe:");
pid = fork();
if (pid < 0)
eprintf("fork:");
else if (!pid) {
dup2(fileno(fp), 0);
dup2(fds[1], 1);
close(fds[0]);
close(fds[1]);
switch (filtermode) {
case 'j':
execlp("bzip2", "bzip2", "-cd", (char *)0);
eprintf("execlp bzip2:");
case 'z':
execlp("gzip", "gzip", "-cd", (char *)0);
eprintf("execlp gzip:");
break;
}
}
close(fds[1]);
return fdopen(fds[0], "r");
}
static void
putoctal(char *dst, unsigned num, int n)
{
snprintf(dst, n, "%.*o", n - 1, num);
}
static int
archive(const char* path)
{
FILE *f;
mode_t mode;
struct group *gr;
struct header *h;
struct passwd *pw;
struct stat st;
size_t chksum, l, x;
unsigned char b[BLKSIZ];
lstat(path, &st);
if (st.st_ino == tarinode && st.st_dev == tardev) {
fprintf(stderr, "ignoring '%s'\n", path);
return 0;
}
pw = getpwuid(st.st_uid);
gr = getgrgid(st.st_gid);
h = (void*)b;
memset(b, 0, sizeof(b));
snprintf(h->name, sizeof(h->name), "%s", path);
putoctal(h->mode, (unsigned)st.st_mode & 0777, sizeof(h->mode));
putoctal(h->uid, (unsigned)st.st_uid, sizeof(h->uid));
putoctal(h->gid, (unsigned)st.st_gid, sizeof(h->gid));
putoctal(h->size, 0, sizeof(h->size));
putoctal(h->mtime, (unsigned)st.st_mtime, sizeof(h->mtime));
memcpy(h->magic, "ustar", sizeof(h->magic));
memcpy(h->version, "00", sizeof(h->version));
snprintf(h->uname, sizeof h->uname, "%s", pw ? pw->pw_name : "");
snprintf(h->gname, sizeof h->gname, "%s", gr ? gr->gr_name : "");
mode = st.st_mode;
if (S_ISREG(mode)) {
h->type = REG;
putoctal(h->size, (unsigned)st.st_size, sizeof h->size);
f = fopen(path, "r");
} else if (S_ISDIR(mode)) {
h->type = DIRECTORY;
} else if (S_ISLNK(mode)) {
h->type = SYMLINK;
readlink(path, h->link, (sizeof h->link)-1);
} else if (S_ISCHR(mode) || S_ISBLK(mode)) {
h->type = S_ISCHR(mode) ? CHARDEV : BLOCKDEV;
#if defined(major) && defined(minor)
putoctal(h->major, (unsigned)major(st.st_dev), sizeof h->major);
putoctal(h->minor, (unsigned)minor(st.st_dev), sizeof h->minor);
#else
return 0;
#endif
} else if (S_ISFIFO(mode)) {
h->type = FIFO;
}
memset(h->chksum, ' ', sizeof h->chksum);
for (x = 0, chksum = 0; x < sizeof *h; x++)
chksum += b[x];
putoctal(h->chksum, chksum, sizeof h->chksum);
fwrite(b, BLKSIZ, 1, tarfile);
if (!f)
return 0;
while ((l = fread(b, 1, BLKSIZ, f)) > 0) {
if (l < BLKSIZ)
memset(b+l, 0, BLKSIZ-l);
fwrite(b, BLKSIZ, 1, tarfile);
}
fclose(f);
return 0;
}
static int
unarchive(char *fname, int l, char b[BLKSIZ])
{
FILE *f = NULL;
struct timeval times[2];
struct header *h = (void*)b;
unsigned long mode, major, minor, type, mtime;
char lname[101];
if (!mflag)
mtime = strtoul(h->mtime, 0, 8);
unlink(fname);
switch (h->type) {
case REG:
case AREG:
mode = strtoul(h->mode, 0, 8);
if (!(f = fopen(fname, "w")) || chmod(fname, mode))
perror(fname);
break;
case HARDLINK:
case SYMLINK:
snprintf(lname, sizeof lname, "%s", h->link);
if (!((h->type == HARDLINK) ? link : symlink)(lname, fname))
perror(fname);
break;
case DIRECTORY:
mode = strtoul(h->mode, 0, 8);
if (mkdir(fname, (mode_t)mode))
perror(fname);
break;
case CHARDEV:
case BLOCKDEV:
#ifdef makedev
mode = strtoul(h->mode, 0, 8);
major = strtoul(h->major, 0, 8);
minor = strtoul(h->mode, 0, 8);
type = (h->type == CHARDEV) ? S_IFCHR : S_IFBLK;
if (mknod(fname, type | mode, makedev(major, minor)))
perror(fname);
#endif
break;
case FIFO:
mode = strtoul(h->mode, 0, 8);
if (mknod(fname, S_IFIFO | mode, 0))
perror(fname);
break;
default:
fprintf(stderr, "usupported tarfiletype %c\n", h->type);
}
if (getuid() == 0 && chown(fname, strtoul(h->uid, 0, 8), strtoul(h->gid, 0, 8)))
perror(fname);
for (; l > 0; l -= BLKSIZ) {
fread(b, BLKSIZ, 1, tarfile);
if (f)
fwrite(b, MIN(l, 512), 1, f);
}
if (f)
fclose(f);
if (!mflag) {
times[0].tv_sec = times[1].tv_sec = mtime;
times[0].tv_usec = times[1].tv_usec = 0;
if (utimes(fname, times))
perror(fname);
}
return 0;
}
static int
print(char * fname, int l, char b[BLKSIZ])
{
puts(fname);
for (; l > 0; l -= BLKSIZ)
fread(b, BLKSIZ, 1, tarfile);
return 0;
}
static void
c(const char * path, int fflag)
{
archive(path);
recurse(path, c, fflag);
}
static void
xt(int (*fn)(char*, int, char[BLKSIZ]))
{
char b[BLKSIZ], fname[257], *s;
struct header *h = (void*)b;
while (fread(b, BLKSIZ, 1, tarfile) && h->name[0] != '\0') {
s = fname;
if (h->prefix[0] != '\0')
s += sprintf(s, "%.*s/", (int)sizeof h->prefix, h->prefix);
sprintf(s, "%.*s", (int)sizeof h->name, h->name);
fn(fname, strtol(h->size, 0, 8), b);
}
}
static void
usage(void)
{
eprintf("usage: tar [-f tarfile] [-C dir] -j|z -x[m]|t\n"
" tar [-f tarfile] [-C dir] -c dir\n");
}
int
main(int argc, char *argv[])
{
FILE *fp;
struct stat st;
char *file = NULL, *dir = ".", mode = '\0';
ARGBEGIN {
case 'x':
case 'c':
case 't':
if (mode)
usage();
mode = ARGC();
break;
case 'C':
dir = EARGF(usage());
break;
case 'f':
file = EARGF(usage());
break;
case 'm':
mflag = 1;
break;
case 'j':
case 'z':
if (filtermode)
usage();
filtermode = ARGC();
break;
case 'h':
fflag = 'L';
break;
default:
usage();
} ARGEND;
if (!mode || argc != (mode == 'c'))
usage();
switch (mode) {
case 'c':
if (file) {
if (!(fp = fopen(file, "w")))
eprintf("fopen %s:", file);
if (lstat(file, &st) < 0)
eprintf("tar: stat '%s':", file);
tarinode = st.st_ino;
tardev = st.st_dev;
tarfile = fp;
} else {
tarfile = stdout;
}
chdir(dir);
c(argv[0], fflag);
break;
case 't':
case 'x':
if (file) {
if (!(fp = fopen(file, "r")))
eprintf("fopen %s:", file);
} else {
fp = stdin;
}
switch (filtermode) {
case 'j':
case 'z':
tarfile = decomp(fp);
break;
default:
tarfile = fp;
break;
}
chdir(dir);
xt(mode == 'x' ? unarchive : print);
break;
}
return 0;
}