mirror of
git://git.suckless.org/sbase
synced 2026-01-26 05:37:54 +00:00
tar: bug fix and compatibility improvements
1. A fix for a bug in the unarchive() function (causing metadata loss when used on large tar files). This bug is due to existing code continuing to check for h->type == HARDLINK and SOFTLINK (near end of function), when the entire header block has already been overwritten by a call to eread() prior to the h->type checks. 2. Long (>=256 byte) file name compatibility: 'L' style long file names were extremely simple to add, requiring a (net) addition of a handful lines of code, and this patch supports both extracting and creating L-style tar archives. Pax 'x' style long names are more complex to parse, and this patch only supports extracting pax 'x' tars, but not creating them. 3. Command line argument compatibility improvements: 'c', 'x', 't' args are accepted without needing a hyphen in front. The '-p' flag is also accepted but is no-op (as it is the normal behaviour of sbase tar anyway, and allows sbase tar to be used in scripts specifying this flag). Directory tree member extraction is also supported by this patch. 4. Handle tar archives with "." (current directory) entries. Some archives contain "." or "./" entries, causing error reports when the current code tries to remove() the current dir. I have added a check in unarchive() to not perform remove() on encountering these entries.
This commit is contained in:
Xan Phung
Roberto E. Vargas Caballero
parent
cfe9424ba9
commit
5aa63dbe05
212
tar.c
212
tar.c
@ -6,6 +6,7 @@
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#include <sys/sysmacros.h>
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#endif
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#include <assert.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <grp.h>
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@ -19,7 +20,7 @@
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#include "fs.h"
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#include "util.h"
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#define BLKSIZ 512
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#define BLKSIZ (sizeof (struct header)) /* must equal 512 bytes */
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enum Type {
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REG = '0',
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@ -50,6 +51,7 @@ struct header {
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char major[8];
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char minor[8];
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char prefix[155];
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char padding[12];
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};
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static struct dirtime {
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@ -169,6 +171,17 @@ ewrite(int fd, const void *buf, size_t n)
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return r;
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}
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static unsigned
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chksum(struct header *h)
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{
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unsigned sum, i;
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memset(h->chksum, ' ', sizeof(h->chksum));
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for (i = 0, sum = 0, assert(BLKSIZ == 512); i < BLKSIZ; i++)
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sum += *((unsigned char *)h + i);
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return sum;
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}
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static void
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putoctal(char *dst, unsigned num, int size)
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{
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@ -179,14 +192,16 @@ putoctal(char *dst, unsigned num, int size)
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static int
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archive(const char *path)
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{
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char b[BLKSIZ];
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const char *base, *p;
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static const struct header blank = {
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"././@LongLink", "0000000" , "0000000", "0000000", "00000000000",
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"00000000000" , " ", AREG , "" , "ustar", "00",
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};
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char b[BLKSIZ + BLKSIZ], *p;
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struct header *h = (struct header *)b;
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struct group *gr;
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struct header *h;
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struct passwd *pw;
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struct stat st;
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size_t chksum, i, nlen, plen;
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ssize_t l, r;
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ssize_t l, n, r;
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int fd = -1;
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if (lstat(path, &st) < 0) {
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@ -196,47 +211,37 @@ archive(const char *path)
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weprintf("ignoring %s\n", path);
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return 0;
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}
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pw = getpwuid(st.st_uid);
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gr = getgrgid(st.st_gid);
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h = (struct header *)b;
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memset(b, 0, sizeof(b));
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*h = blank;
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n = strlcpy(h->name, path, sizeof(h->name));
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if (n >= sizeof(h->name)) {
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*++h = blank;
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h->type = 'L';
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putoctal(h->size, n, sizeof(h->size));
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putoctal(h->chksum, chksum(h), sizeof(h->chksum));
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plen = 0;
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base = path;
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if ((nlen = strlen(base)) >= sizeof(h->name)) {
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/*
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* Cover case where path name is too long (in which case we
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* need to split it to prefix and name).
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*/
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if ((base = strrchr(path, '/')) == NULL)
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goto too_long;
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for (p = base++; p > path && *p == '/'; --p)
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;
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nlen -= base - path;
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plen = p - path + 1;
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if (nlen >= sizeof(h->name) || plen >= sizeof(h->prefix))
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goto too_long;
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ewrite(tarfd, (char *)h, BLKSIZ);
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for (p = (char *)path; n > 0; n -= BLKSIZ, p += BLKSIZ) {
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if (n < BLKSIZ) {
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p = memcpy(h--, p, n);
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memset(p + n, 0, BLKSIZ - n);
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}
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ewrite(tarfd, p, BLKSIZ);
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}
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}
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memcpy(h->name, base, nlen);
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memcpy(h->prefix, path, plen);
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putoctal(h->mode, (unsigned)st.st_mode & 0777, sizeof(h->mode));
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putoctal(h->uid, (unsigned)st.st_uid, sizeof(h->uid));
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putoctal(h->gid, (unsigned)st.st_gid, sizeof(h->gid));
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putoctal(h->size, 0, sizeof(h->size));
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putoctal(h->mtime, (unsigned)st.st_mtime, sizeof(h->mtime));
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memcpy( h->magic, "ustar", sizeof(h->magic));
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memcpy( h->version, "00", sizeof(h->version));
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estrlcpy(h->uname, pw ? pw->pw_name : "", sizeof(h->uname));
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estrlcpy(h->gname, gr ? gr->gr_name : "", sizeof(h->gname));
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if (S_ISREG(st.st_mode)) {
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h->type = REG;
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putoctal(h->size, (unsigned)st.st_size, sizeof(h->size));
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putoctal(h->size, st.st_size, sizeof(h->size));
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fd = open(path, O_RDONLY);
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if (fd < 0)
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eprintf("open %s:", path);
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@ -255,10 +260,7 @@ archive(const char *path)
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h->type = FIFO;
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}
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memset(h->chksum, ' ', sizeof(h->chksum));
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for (i = 0, chksum = 0; i < sizeof(*h); i++)
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chksum += (unsigned char)b[i];
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putoctal(h->chksum, chksum, sizeof(h->chksum));
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putoctal(h->chksum, chksum(h), sizeof(h->chksum));
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ewrite(tarfd, b, BLKSIZ);
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if (fd != -1) {
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@ -271,24 +273,21 @@ archive(const char *path)
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}
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return 0;
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too_long:
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eprintf("filename too long: %s\n", path);
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}
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static int
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unarchive(char *fname, ssize_t l, char b[BLKSIZ])
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{
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struct header *h = (struct header *)b;
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struct timespec times[2];
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char lname[101], *tmp, *p;
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long mode, major, minor, type, mtime, uid, gid;
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struct header *h = (struct header *)b;
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int fd = -1;
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struct timespec times[2];
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int fd = -1, lnk = h->type == SYMLINK;
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if (!mflag && ((mtime = strtol(h->mtime, &p, 8)) < 0 || *p != '\0'))
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eprintf("strtol %s: invalid number\n", h->mtime);
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if (remove(fname) < 0 && errno != ENOENT)
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weprintf("remove %s:", fname);
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if (strcmp(fname, ".") && strcmp(fname, "./") && remove(fname) < 0)
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if (errno != ENOENT) weprintf("remove %s:", fname);
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tmp = estrdup(fname);
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mkdirp(dirname(tmp), 0777, 0777);
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@ -308,10 +307,9 @@ unarchive(char *fname, ssize_t l, char b[BLKSIZ])
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case SYMLINK:
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snprintf(lname, sizeof(lname), "%.*s", (int)sizeof(h->linkname),
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h->linkname);
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if (((h->type == HARDLINK) ? link : symlink)(lname, fname) < 0)
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eprintf("%s %s -> %s:",
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(h->type == HARDLINK) ? "link" : "symlink",
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fname, lname);
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if ((lnk ? symlink:link)(lname, fname) < 0)
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eprintf("%s %s -> %s:", lnk ? "symlink":"link", fname, lname);
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lnk++;
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break;
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case DIRECTORY:
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if ((mode = strtol(h->mode, &p, 8)) < 0 || *p != '\0')
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@ -354,14 +352,14 @@ unarchive(char *fname, ssize_t l, char b[BLKSIZ])
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close(fd);
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}
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if (h->type == HARDLINK)
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if (lnk == 1)
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return 0;
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times[0].tv_sec = times[1].tv_sec = mtime;
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times[0].tv_nsec = times[1].tv_nsec = 0;
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if (!mflag && utimensat(AT_FDCWD, fname, times, AT_SYMLINK_NOFOLLOW) < 0)
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weprintf("utimensat %s:", fname);
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if (h->type == SYMLINK) {
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if (lnk) {
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if (!getuid() && lchown(fname, uid, gid))
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weprintf("lchown %s:", fname);
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} else {
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@ -435,9 +433,9 @@ sanitize(struct header *h)
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static void
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chktar(struct header *h)
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{
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char tmp[8], *err, *p = (char *)h;
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const char *reason;
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long s1, s2, i;
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char tmp[sizeof h->chksum], *err = "";
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long sum, i;
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if (h->prefix[0] == '\0' && h->name[0] == '\0') {
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reason = "empty filename";
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@ -448,23 +446,19 @@ chktar(struct header *h)
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goto bad;
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}
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memcpy(tmp, h->chksum, sizeof(tmp));
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for (i = 0; i < sizeof(tmp) && tmp[i] == ' '; i++);
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for (; i < sizeof(tmp); i++)
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if (tmp[i] == ' ')
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for (i = sizeof(tmp)-1; i > 0 && tmp[i] == ' '; i--) {
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tmp[i] = '\0';
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s1 = strtol(tmp, &err, 8);
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if (s1 < 0 || *err != '\0') {
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}
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sum = strtol(tmp, &err, 8);
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if (sum < 0 || sum >= BLKSIZ*256 || *err != '\0') {
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reason = "invalid checksum";
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goto bad;
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}
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memset(h->chksum, ' ', sizeof(h->chksum));
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for (i = 0, s2 = 0; i < sizeof(*h); i++)
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s2 += (unsigned char)p[i];
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if (s1 != s2) {
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if (sum != chksum(h)) {
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reason = "incorrect checksum";
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goto bad;
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}
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memcpy(h->chksum, tmp, sizeof(h->chksum));
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memcpy(h->chksum, tmp, sizeof(tmp));
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return;
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bad:
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eprintf("malformed tar archive: %s\n", reason);
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@ -473,45 +467,70 @@ bad:
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static void
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xt(int argc, char *argv[], int mode)
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{
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char b[BLKSIZ], fname[256 + 1], *p;
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long size, l;
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char b[BLKSIZ], fname[l = PATH_MAX + 1], *p, *q = NULL;
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int i, m, n;
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int (*fn)(char *, ssize_t, char[BLKSIZ]) = (mode == 'x') ? unarchive : print;
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struct timespec times[2];
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struct header *h = (struct header *)b;
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struct dirtime *dirtime;
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long size;
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int i, n;
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int (*fn)(char *, ssize_t, char[BLKSIZ]) = (mode == 'x') ? unarchive : print;
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while (eread(tarfd, b, BLKSIZ) > 0 && (h->name[0] || h->prefix[0])) {
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chktar(h);
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sanitize(h), n = 0;
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/* small dance around non-null terminated fields */
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if (h->prefix[0])
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n = snprintf(fname, sizeof(fname), "%.*s/",
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(int)sizeof(h->prefix), h->prefix);
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snprintf(fname + n, sizeof(fname) - n, "%.*s",
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(int)sizeof(h->name), h->name);
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sanitize(h);
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if ((size = strtol(h->size, &p, 8)) < 0 || *p != '\0')
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eprintf("strtol %s: invalid number\n", h->size);
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eprintf("strtol %s: invalid size\n", h->size);
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if (argc) {
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/* only extract the given files */
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for (i = 0; i < argc; i++)
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if (!strcmp(argv[i], fname))
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/* Long file path is read direcly into fname*/
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if (h->type == 'L' || h->type == 'x' || h->type == 'g') {
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/* Read header only up to size of fname buffer */
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for (q = fname; q < fname+size; q += BLKSIZ) {
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if (q + BLKSIZ >= fname + l)
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eprintf("name exceeds buffer: %s\n", fname);
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eread(tarfd, q, BLKSIZ);
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}
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/* Convert pax x header with 'path=' field into L header */
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if (h->type == 'x') for (q = fname; q < fname+size-16; q += n) {
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if ((n = strtol(q, &p, 10)) < 0 || *p != ' ')
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eprintf("strtol %.*s: invalid number\n", p+1-q, q);
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if (n && strncmp(p+1, "path=", 5) == 0) {
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memmove(fname, p+6, size = q+n - p-6 - 1);
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h->type = 'L';
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break;
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}
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}
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fname[size] = '\0';
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/* Non L-like header (eg. pax 'g') is skipped by setting q=null */
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if (h->type != 'L')
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q = NULL;
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continue;
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}
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/* Ustar path is copied into fname if no L header (ie: q is NULL) */
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if (!q) {
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m = sizeof h->prefix, n = sizeof h->name;
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p = "/" + !h->prefix[0];
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snprintf(fname, l, "%.*s%s%.*s", m, h->prefix, p, n, h->name);
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}
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q = NULL;
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/* If argc > 0 then only extract the given files/dirs */
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if (argc) {
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for (i = 0; i < argc; i++) {
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if (strncmp(argv[i], fname, n = strlen(argv[i])) == 0)
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if (strchr("/", fname[n]) || argv[i][n-1] == '/')
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break;
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}
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if (i == argc) {
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skipblk(size);
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continue;
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}
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}
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/* ignore global pax header craziness */
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if (h->type == 'g' || h->type == 'x') {
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skipblk(size);
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continue;
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}
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fn(fname, size, b);
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if (vflag && mode != 't')
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puts(fname);
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@ -530,12 +549,15 @@ xt(int argc, char *argv[], int mode)
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}
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}
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char **args;
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int argn;
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static void
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usage(void)
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{
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eprintf("usage: %s [-C dir] [-J | -Z | -a | -j | -z] -x [-m | -t] "
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eprintf("usage: %s [x | t | -x | -t] [-C dir] [-J | -Z | -a | -j | -z] [-m] [-p] "
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"[-f file] [file ...]\n"
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" %s [-C dir] [-J | -Z | -a | -j | -z] [-h] -c path ... "
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" %s [c | -c] [-C dir] [-J | -Z | -a | -j | -z] [-h] path ... "
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"[-f file]\n", argv0, argv0);
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}
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@ -547,6 +569,10 @@ main(int argc, char *argv[])
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char *file = NULL, *dir = ".", mode = '\0';
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int fd;
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argv0 = argv[0];
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if (argc > 1 && strchr("cxt", mode = *argv[1]))
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*(argv[1]+1) ? *argv[1] = '-' : (*++argv = argv0, --argc);
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ARGBEGIN {
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case 'x':
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case 'c':
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@ -576,18 +602,16 @@ main(int argc, char *argv[])
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case 'v':
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vflag = 1;
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break;
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case 'p':
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break; /* Do nothing as already default behaviour */
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default:
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usage();
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} ARGEND
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if (!mode)
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usage();
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if (mode == 'c')
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if (!argc)
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usage();
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switch (mode) {
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case 'c':
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if (!argc)
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usage();
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tarfd = 1;
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if (file && *file != '-') {
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tarfd = open(file, O_WRONLY | O_TRUNC | O_CREAT, 0644);
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@ -626,6 +650,8 @@ main(int argc, char *argv[])
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eprintf("chdir %s:", dir);
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xt(argc, argv, mode);
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break;
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default:
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usage();
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}
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return recurse_status;
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