tar: Use raw I/O instead of standard file streams
As part of refactoring tar to add support for compression through gzip/bzip2, it makes sense to avoid intermixing file stream I/O with raw I/O.
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124
tar.c
124
tar.c
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@ -3,6 +3,7 @@
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#include <sys/time.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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#include <libgen.h>
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#include <pwd.h>
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@ -47,8 +48,7 @@ enum Type {
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BLOCKDEV = '4', DIRECTORY = '5', FIFO = '6'
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};
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static FILE *tarfile;
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static char *tarfilename;
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static int tarfd;
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static ino_t tarinode;
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static dev_t tardev;
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@ -59,6 +59,7 @@ static struct ent {
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char *name;
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time_t mtime;
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} *ents;
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static size_t entlen;
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static void
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@ -80,8 +81,8 @@ popent(void)
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return NULL;
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}
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static FILE *
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decomp(FILE *fp)
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static int
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decomp(int fd)
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{
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int fds[2];
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char *tool;
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@ -93,7 +94,7 @@ decomp(FILE *fp)
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case -1:
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eprintf("fork:");
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case 0:
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dup2(fileno(fp), 0);
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dup2(fd, 0);
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dup2(fds[1], 1);
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close(fds[0]);
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close(fds[1]);
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@ -104,8 +105,32 @@ decomp(FILE *fp)
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_exit(1);
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}
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close(fds[1]);
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return fds[0];
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}
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return fdopen(fds[0], "r");
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static ssize_t
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eread(int fd, void *buf, size_t n)
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{
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ssize_t r;
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again:
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r = read(fd, buf, n);
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if (r < 0) {
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if (errno == EINTR)
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goto again;
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eprintf("read:");
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}
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return r;
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}
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static ssize_t
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ewrite(int fd, const void *buf, size_t n)
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{
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ssize_t r;
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if ((r = write(fd, buf, n)) != n)
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eprintf("write:");
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return r;
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}
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static void
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@ -118,14 +143,14 @@ 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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FILE *f = NULL;
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unsigned char b[BLKSIZ];
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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, x;
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ssize_t l, r;
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unsigned char b[BLKSIZ];
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int fd = -1;
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if (lstat(path, &st) < 0) {
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weprintf("lstat %s:", path);
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@ -154,7 +179,9 @@ archive(const char *path)
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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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f = fopen(path, "r");
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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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} else if (S_ISDIR(st.st_mode)) {
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h->type = DIRECTORY;
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} else if (S_ISLNK(st.st_mode)) {
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@ -174,18 +201,15 @@ archive(const char *path)
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for (x = 0, chksum = 0; x < sizeof(*h); x++)
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chksum += b[x];
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putoctal(h->chksum, chksum, sizeof(h->chksum));
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ewrite(tarfd, b, BLKSIZ);
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if (fwrite(b, BLKSIZ, 1, tarfile) != 1)
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eprintf("fwrite:");
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if (f) {
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while ((l = fread(b, 1, BLKSIZ, f)) > 0) {
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if (fd != -1) {
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while ((l = eread(fd, b, BLKSIZ)) > 0) {
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if (l < BLKSIZ)
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memset(b + l, 0, BLKSIZ - l);
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if (fwrite(b, BLKSIZ, 1, tarfile) != 1)
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eprintf("fwrite:");
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ewrite(tarfd, b, BLKSIZ);
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}
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efshut(f, path);
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close(fd);
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}
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return 0;
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@ -194,10 +218,10 @@ archive(const char *path)
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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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FILE *f = NULL;
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struct header *h = (struct header *)b;
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long mode, major, minor, type, mtime, uid, gid;
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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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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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@ -213,10 +237,11 @@ unarchive(char *fname, ssize_t l, char b[BLKSIZ])
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case AREG:
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if ((mode = strtol(h->mode, &p, 8)) < 0 || *p != '\0')
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eprintf("strtol %s: invalid number\n", h->mode);
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if (!(f = fopen(fname, "w")))
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eprintf("fopen %s:", fname);
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if (chmod(fname, mode) < 0)
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eprintf("chmod %s:", fname);
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fd = open(fname, O_WRONLY | O_TRUNC | O_CREAT, 0644);
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if (fd < 0)
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eprintf("open %s:", fname);
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if (fchmod(fd, mode) < 0)
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eprintf("fchmod %s:", fname);
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break;
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case HARDLINK:
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case SYMLINK:
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@ -262,14 +287,12 @@ unarchive(char *fname, ssize_t l, char b[BLKSIZ])
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if (!getuid() && chown(fname, uid, gid))
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weprintf("chown %s:", fname);
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for (; l > 0; l -= BLKSIZ) {
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if (fread(b, BLKSIZ, 1, tarfile) != 1)
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eprintf("fread %s:", tarfilename);
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if (f && fwrite(b, MIN(l, BLKSIZ), 1, f) != 1)
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eprintf("fwrite %s:", fname);
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if (fd != -1) {
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for (; l > 0; l -= BLKSIZ)
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if (eread(tarfd, b, BLKSIZ) > 0)
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ewrite(fd, b, MIN(l, BLKSIZ));
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close(fd);
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}
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if (f)
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fshut(f, fname);
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pushent(fname, mtime);
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return 0;
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@ -281,8 +304,8 @@ skipblk(ssize_t l)
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char b[BLKSIZ];
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for (; l > 0; l -= BLKSIZ)
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if (fread(b, BLKSIZ, 1, tarfile) != 1)
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eprintf("fread %s:", tarfilename);
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if (!eread(tarfd, b, BLKSIZ))
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break;
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}
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static int
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@ -339,7 +362,7 @@ xt(int argc, char *argv[], int (*fn)(char *, ssize_t, char[BLKSIZ]))
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long size;
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int i, n;
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while (fread(b, BLKSIZ, 1, tarfile) == 1 && *h->name) {
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while (eread(tarfd, b, BLKSIZ) > 0 && h->name[0]) {
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sanitize(h), n = 0;
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/* small dance around non-null terminated fields */
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@ -371,8 +394,6 @@ xt(int argc, char *argv[], int (*fn)(char *, ssize_t, char[BLKSIZ]))
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fn(fname, size, b);
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}
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if (ferror(tarfile))
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eprintf("fread %s:", tarfilename);
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if (!mflag) {
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while ((ent = popent())) {
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@ -397,11 +418,11 @@ usage(void)
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int
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main(int argc, char *argv[])
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{
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FILE *fp;
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struct recursor r = { .fn = c, .hist = NULL, .depth = 0, .maxdepth = 0,
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.follow = 'P', .flags = DIRFIRST };
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struct stat st;
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char *file = NULL, *dir = ".", mode = '\0';
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int fd;
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ARGBEGIN {
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case 'x':
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@ -437,19 +458,17 @@ main(int argc, char *argv[])
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switch (mode) {
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case 'c':
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tarfd = 1;
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if (file) {
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if (!(fp = fopen(file, "w")))
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eprintf("fopen %s:", file);
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tarfd = open(file, O_WRONLY | O_TRUNC | O_CREAT, 0644);
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if (tarfd < 0)
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eprintf("open %s:", file);
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if (lstat(file, &st) < 0)
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eprintf("lstat %s:", file);
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tarinode = st.st_ino;
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tardev = st.st_dev;
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tarfile = fp;
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tarfilename = file;
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} else {
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tarfile = stdout;
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tarfilename = "<stdout>";
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}
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if (chdir(dir) < 0)
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eprintf("chdir %s:", dir);
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for (; *argv; argc--, argv++)
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@ -457,22 +476,19 @@ main(int argc, char *argv[])
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break;
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case 't':
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case 'x':
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tarfd = 0;
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if (file) {
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if (!(fp = fopen(file, "r")))
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eprintf("fopen %s:", file);
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} else {
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fp = stdin;
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tarfd = open(file, O_RDONLY);
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if (tarfd < 0)
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eprintf("open %s:", file);
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}
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tarfilename = file;
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switch (filtermode) {
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case 'j':
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case 'z':
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tarfile = decomp(fp);
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break;
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default:
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tarfile = fp;
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fd = tarfd;
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tarfd = decomp(tarfd);
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close(fd);
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break;
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}
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