1 /* tar.c - create/extract archives
2  *
3  * Copyright 2014 Ashwini Kumar <ak.ashwini81@gmail.com>
4  *
5  * USTAR interchange format is of interest in
6  * See http://http://pubs.opengroup.org/onlinepubs/9699919799/utilities/pax.html
7  * For writing to external program
8  * http://www.gnu.org/software/tar/manual/html_node/Writing-to-an-External-Program.html
9 
10 USE_TAR(NEWTOY(tar, "&(no-recursion)(numeric-owner)(no-same-permissions)(overwrite)(exclude)*(to-command):o(no-same-owner)p(same-permissions)k(keep-old)c(create)|h(dereference)x(extract)|t(list)|v(verbose)j(bzip2)z(gzip)O(to-stdout)m(touch)X(exclude-from)*T(files-from)*C(directory):f(file):[!txc][!jz]", TOYFLAG_USR|TOYFLAG_BIN))
11 
12 config TAR
13   bool "tar"
14   default n
15   help
16     usage: tar -[cxtjzhmvO] [-X FILE] [-T FILE] [-f TARFILE] [-C DIR]
17 
18     Create, extract, or list files from a tar file
19 
20     Operation:
21     c Create
22     f Name of TARFILE ('-' for stdin/out)
23     h Follow symlinks
24     j (De)compress using bzip2
25     m Don't restore mtime
26     t List
27     v Verbose
28     x Extract
29     z (De)compress using gzip
30     C Change to DIR before operation
31     O Extract to stdout
32     exclude=FILE File to exclude
33     X File with names to exclude
34     T File with names to include
35 */
36 
37 #define FOR_tar
38 #include "toys.h"
39 
40 GLOBALS(
41   char *fname;
42   char *dir;
43   struct arg_list *inc_file;
44   struct arg_list *exc_file;
45   char *tocmd;
46   struct arg_list *exc;
47 
48   struct arg_list *inc, *pass;
49   void *inodes, *handle;
50 )
51 
52 struct tar_hdr {
53   char name[100], mode[8], uid[8], gid[8],size[12], mtime[12], chksum[8],
54        type, link[100], magic[8], uname[32], gname[32], major[8], minor[8],
55        prefix[155], padd[12];
56 };
57 
58 struct file_header {
59   char *name, *link_target, *uname, *gname;
60   off_t size;
61   uid_t uid;
62   gid_t gid;
63   mode_t mode;
64   time_t mtime;
65   dev_t device;
66 };
67 
68 struct archive_handler {
69   int src_fd;
70   struct file_header file_hdr;
71   off_t offset;
72   void (*extract_handler)(struct archive_handler*);
73 };
74 
75 struct inode_list {
76   struct inode_list *next;
77   char *arg;
78   ino_t ino;
79   dev_t dev;
80 };
81 
copy_in_out(int src,int dst,off_t size)82 static void copy_in_out(int src, int dst, off_t size)
83 {
84   int i, rd, rem = size%512, cnt;
85 
86   cnt = size/512 + (rem?1:0);
87 
88   for (i = 0; i < cnt; i++) {
89     rd = (i == cnt-1 && rem) ? rem : 512;
90     xreadall(src, toybuf, rd);
91     writeall(dst, toybuf, rd);
92   }
93 }
94 
95 //convert to octal
itoo(char * str,int len,off_t val)96 static void itoo(char *str, int len, off_t val)
97 {
98   char *t, tmp[sizeof(off_t)*3+1];
99   int cnt  = sprintf(tmp, "%0*llo", len, (unsigned long long)val);
100 
101   t = tmp + cnt - len;
102   if (*t == '0') t++;
103   memcpy(str, t, len);
104 }
105 
seen_inode(void ** list,struct stat * st,char * name)106 static struct inode_list *seen_inode(void **list, struct stat *st, char *name)
107 {
108   if (!st) llist_traverse(*list, llist_free_arg);
109   else if (!S_ISDIR(st->st_mode) && st->st_nlink > 1) {
110     struct inode_list *new;
111 
112     for (new = *list; new; new = new->next)
113       if(new->ino == st->st_ino && new->dev == st->st_dev)
114         return new;
115 
116     new = xzalloc(sizeof(*new));
117     new->ino = st->st_ino;
118     new->dev = st->st_dev;
119     new->arg = xstrdup(name);
120     new->next = *list;
121     *list = new;
122   }
123   return 0;
124 }
125 
write_longname(struct archive_handler * tar,char * name,char type)126 static void write_longname(struct archive_handler *tar, char *name, char type)
127 {
128   struct tar_hdr tmp;
129   unsigned int sum = 0;
130   int i, sz = strlen(name) +1;
131   char buf[512] = {0,};
132 
133   memset(&tmp, 0, sizeof(tmp));
134   strcpy(tmp.name, "././@LongLink");
135   sprintf(tmp.mode, "%0*d", (int)sizeof(tmp.mode)-1, 0);
136   sprintf(tmp.uid, "%0*d", (int)sizeof(tmp.uid)-1, 0);
137   sprintf(tmp.gid, "%0*d", (int)sizeof(tmp.gid)-1, 0);
138   sprintf(tmp.size, "%0*d", (int)sizeof(tmp.size)-1, 0);
139   sprintf(tmp.mtime, "%0*d", (int)sizeof(tmp.mtime)-1, 0);
140   itoo(tmp.size, sizeof(tmp.size), sz);
141   tmp.type = type;
142   memset(tmp.chksum, ' ', 8);
143   strcpy(tmp.magic, "ustar  ");
144   for (i= 0; i < 512; i++) sum += (unsigned int)((char*)&tmp)[i];
145   itoo(tmp.chksum, sizeof(tmp.chksum)-1, sum);
146 
147   writeall(tar->src_fd, (void*) &tmp, sizeof(tmp));
148   //write name to archive
149   writeall(tar->src_fd, name, sz);
150   if (sz%512) writeall(tar->src_fd, buf, (512-(sz%512)));
151 }
152 
filter(struct arg_list * lst,char * name)153 static int filter(struct arg_list *lst, char *name)
154 {
155   struct arg_list *cur;
156 
157   for (cur = lst; cur; cur = cur->next)
158     if (!fnmatch(cur->arg, name, 1<<3)) return 1;
159   return 0;
160 }
161 
add_file(struct archive_handler * tar,char ** nam,struct stat * st)162 static void add_file(struct archive_handler *tar, char **nam, struct stat *st)
163 {
164   struct tar_hdr hdr;
165   struct passwd *pw;
166   struct group *gr;
167   struct inode_list *node;
168   int i, fd =-1;
169   char *c, *p, *name = *nam, *lnk, *hname, buf[512] = {0,};
170   unsigned int sum = 0;
171   static int warn = 1;
172 
173   for (p = name; *p; p++)
174     if ((p == name || p[-1] == '/') && *p != '/'
175         && filter(TT.exc, p)) return;
176 
177   if (S_ISDIR(st->st_mode) && name[strlen(name)-1] != '/') {
178     lnk = xmprintf("%s/",name);
179     free(name);
180     *nam = name = lnk;
181   }
182   hname = name;
183   //remove leading '/' or relative path '../' component
184   if (*hname == '/') hname++;
185   if (!*hname) return;
186   while ((c = strstr(hname, "../"))) hname = c + 3;
187   if (warn && hname != name) {
188     fprintf(stderr, "removing leading '%.*s' "
189         "from member names\n", (int)(hname-name), name);
190     warn = 0;
191   }
192 
193   memset(&hdr, 0, sizeof(hdr));
194   strncpy(hdr.name, hname, sizeof(hdr.name));
195   itoo(hdr.mode, sizeof(hdr.mode), st->st_mode &07777);
196   itoo(hdr.uid, sizeof(hdr.uid), st->st_uid);
197   itoo(hdr.gid, sizeof(hdr.gid), st->st_gid);
198   itoo(hdr.size, sizeof(hdr.size), 0); //set size later
199   itoo(hdr.mtime, sizeof(hdr.mtime), st->st_mtime);
200   for (i=0; i<sizeof(hdr.chksum); i++) hdr.chksum[i] = ' ';
201 
202   if ((node = seen_inode(&TT.inodes, st, hname))) {
203     //this is a hard link
204     hdr.type = '1';
205     if (strlen(node->arg) > sizeof(hdr.link))
206       write_longname(tar, hname, 'K'); //write longname LINK
207     xstrncpy(hdr.link, node->arg, sizeof(hdr.link));
208   } else if (S_ISREG(st->st_mode)) {
209     hdr.type = '0';
210     if (st->st_size <= (off_t)0777777777777LL)
211       itoo(hdr.size, sizeof(hdr.size), st->st_size);
212     else {
213       error_msg("can't store file '%s' of size '%lld'\n",
214                 hname, (unsigned long long)st->st_size);
215       return;
216     }
217   } else if (S_ISLNK(st->st_mode)) {
218     hdr.type = '2'; //'K' long link
219     if (!(lnk = xreadlink(name))) {
220       perror_msg("readlink");
221       return;
222     }
223     if (strlen(lnk) > sizeof(hdr.link))
224       write_longname(tar, hname, 'K'); //write longname LINK
225     xstrncpy(hdr.link, lnk, sizeof(hdr.link));
226     free(lnk);
227   }
228   else if (S_ISDIR(st->st_mode)) hdr.type = '5';
229   else if (S_ISFIFO(st->st_mode)) hdr.type = '6';
230   else if (S_ISBLK(st->st_mode) || S_ISCHR(st->st_mode)) {
231     hdr.type = (S_ISCHR(st->st_mode))?'3':'4';
232     itoo(hdr.major, sizeof(hdr.major), dev_major(st->st_rdev));
233     itoo(hdr.minor, sizeof(hdr.minor), dev_minor(st->st_rdev));
234   } else {
235     error_msg("unknown file type '%o'", st->st_mode & S_IFMT);
236     return;
237   }
238   if (strlen(hname) > sizeof(hdr.name))
239           write_longname(tar, hname, 'L'); //write longname NAME
240   strcpy(hdr.magic, "ustar  ");
241   if ((pw = getpwuid(st->st_uid)))
242     snprintf(hdr.uname, sizeof(hdr.uname), "%s", pw->pw_name);
243   else snprintf(hdr.uname, sizeof(hdr.uname), "%d", st->st_uid);
244 
245   if ((gr = getgrgid(st->st_gid)))
246     snprintf(hdr.gname, sizeof(hdr.gname), "%s", gr->gr_name);
247   else snprintf(hdr.gname, sizeof(hdr.gname), "%d", st->st_gid);
248 
249   //calculate chksum.
250   for (i= 0; i < 512; i++) sum += (unsigned int)((char*)&hdr)[i];
251   itoo(hdr.chksum, sizeof(hdr.chksum)-1, sum);
252   if (toys.optflags & FLAG_v) printf("%s\n",hname);
253   writeall(tar->src_fd, (void*)&hdr, 512);
254 
255   //write actual data to archive
256   if (hdr.type != '0') return; //nothing to write
257   if ((fd = open(name, O_RDONLY)) < 0) {
258     perror_msg("can't open '%s'", name);
259     return;
260   }
261   copy_in_out(fd, tar->src_fd, st->st_size);
262   if (st->st_size%512) writeall(tar->src_fd, buf, (512-(st->st_size%512)));
263   close(fd);
264 }
265 
add_to_tar(struct dirtree * node)266 static int add_to_tar(struct dirtree *node)
267 {
268   struct stat st;
269   char *path;
270   struct archive_handler *hdl = (struct archive_handler*)TT.handle;
271 
272   if (!fstat(hdl->src_fd, &st) && st.st_dev == node->st.st_dev
273       && st.st_ino == node->st.st_ino) {
274     error_msg("'%s' file is the archive; not dumped", TT.fname);
275     return ((DIRTREE_RECURSE | ((toys.optflags & FLAG_h)?DIRTREE_SYMFOLLOW:0)));
276   }
277 
278   if (!dirtree_notdotdot(node)) return 0;
279   path = dirtree_path(node, 0);
280   add_file(hdl, &path, &(node->st)); //path may be modified
281   free(path);
282   if (toys.optflags & FLAG_no_recursion) return 0;
283   return ((DIRTREE_RECURSE | ((toys.optflags & FLAG_h)?DIRTREE_SYMFOLLOW:0)));
284 }
285 
compress_stream(struct archive_handler * tar_hdl)286 static void compress_stream(struct archive_handler *tar_hdl)
287 {
288   int pipefd[2];
289   pid_t cpid;
290 
291   xpipe(pipefd);
292 
293   signal(SIGPIPE, SIG_IGN);
294   cpid = fork();
295   if (cpid == -1) perror_exit("fork");
296 
297   if (!cpid) {    /* Child reads from pipe */
298     char *argv[] = {(toys.optflags&FLAG_z)?"gzip":"bzip2", "-f", NULL};
299     xclose(pipefd[1]); /* Close unused write*/
300     dup2(pipefd[0], 0);
301     dup2(tar_hdl->src_fd, 1); //write to tar fd
302     xexec(argv);
303   } else {
304     xclose(pipefd[0]);          /* Close unused read end */
305     dup2(pipefd[1], tar_hdl->src_fd); //write to pipe
306   }
307 }
308 
extract_to_stdout(struct archive_handler * tar)309 static void extract_to_stdout(struct archive_handler *tar)
310 {
311   struct file_header *file_hdr = &tar->file_hdr;
312 
313   copy_in_out(tar->src_fd, 0, file_hdr->size);
314   tar->offset += file_hdr->size;
315 }
316 
extract_to_command(struct archive_handler * tar)317 static void extract_to_command(struct archive_handler *tar)
318 {
319   int pipefd[2], status = 0;
320   pid_t cpid;
321   struct file_header *file_hdr = &tar->file_hdr;
322 
323   xpipe(pipefd);
324   if (!S_ISREG(file_hdr->mode)) return; //only regular files are supported.
325 
326   cpid = fork();
327   if (cpid == -1) perror_exit("fork");
328 
329   if (!cpid) {    // Child reads from pipe
330     char buf[64], *argv[4] = {"sh", "-c", TT.tocmd, NULL};
331 
332     setenv("TAR_FILETYPE", "f", 1);
333     sprintf(buf, "%0o", file_hdr->mode);
334     setenv("TAR_MODE", buf, 1);
335     sprintf(buf, "%ld", (long)file_hdr->size);
336     setenv("TAR_SIZE", buf, 1);
337     setenv("TAR_FILENAME", file_hdr->name, 1);
338     setenv("TAR_UNAME", file_hdr->uname, 1);
339     setenv("TAR_GNAME", file_hdr->gname, 1);
340     sprintf(buf, "%0o", (int)file_hdr->mtime);
341     setenv("TAR_MTIME", buf, 1);
342     sprintf(buf, "%0o", file_hdr->uid);
343     setenv("TAR_UID", buf, 1);
344     sprintf(buf, "%0o", file_hdr->gid);
345     setenv("TAR_GID", buf, 1);
346 
347     xclose(pipefd[1]); // Close unused write
348     dup2(pipefd[0], 0);
349     signal(SIGPIPE, SIG_DFL);
350     xexec(argv);
351   } else {
352     xclose(pipefd[0]);  // Close unused read end
353     copy_in_out(tar->src_fd, pipefd[1], file_hdr->size);
354     tar->offset += file_hdr->size;
355     xclose(pipefd[1]);
356     waitpid(cpid, &status, 0);
357     if (WIFSIGNALED(status))
358       xprintf("tar : %d: child returned %d\n", cpid, WTERMSIG(status));
359   }
360 }
361 
extract_to_disk(struct archive_handler * tar)362 static void extract_to_disk(struct archive_handler *tar)
363 {
364   int flags, dst_fd = -1;
365   char *s;
366   struct stat ex;
367   struct file_header *file_hdr = &tar->file_hdr;
368 
369   flags = strlen(file_hdr->name);
370   if (flags>2) {
371     if (strstr(file_hdr->name, "/../") || !strcmp(file_hdr->name, "../") ||
372         !strcmp(file_hdr->name+flags-3, "/.."))
373     {
374       error_msg("drop %s", file_hdr->name);
375     }
376   }
377 
378   if (file_hdr->name[flags-1] == '/') file_hdr->name[flags-1] = 0;
379   //Regular file with preceding path
380   if ((s = strrchr(file_hdr->name, '/'))) {
381     if (mkpath(file_hdr->name) && errno !=EEXIST) {
382       error_msg(":%s: not created", file_hdr->name);
383       return;
384     }
385   }
386 
387   //remove old file, if exists
388   if (!(toys.optflags & FLAG_k) && !S_ISDIR(file_hdr->mode)
389       && !lstat( file_hdr->name, &ex)) {
390     if (unlink(file_hdr->name)) {
391       perror_msg("can't remove: %s",file_hdr->name);
392     }
393   }
394 
395   //hard link
396   if (S_ISREG(file_hdr->mode) && file_hdr->link_target) {
397     if (link(file_hdr->link_target, file_hdr->name))
398       perror_msg("can't link '%s' -> '%s'",file_hdr->name, file_hdr->link_target);
399     goto COPY;
400   }
401 
402   switch (file_hdr->mode & S_IFMT) {
403     case S_IFREG:
404       flags = O_WRONLY|O_CREAT|O_EXCL;
405       if (toys.optflags & FLAG_overwrite) flags = O_WRONLY|O_CREAT|O_TRUNC;
406       dst_fd = open(file_hdr->name, flags, file_hdr->mode & 07777);
407       if (dst_fd == -1) perror_msg("%s: can't open", file_hdr->name);
408       break;
409     case S_IFDIR:
410       if ((mkdir(file_hdr->name, file_hdr->mode) == -1) && errno != EEXIST)
411         perror_msg("%s: can't create", file_hdr->name);
412       break;
413     case S_IFLNK:
414       if (symlink(file_hdr->link_target, file_hdr->name))
415         perror_msg("can't link '%s' -> '%s'",file_hdr->name, file_hdr->link_target);
416       break;
417     case S_IFBLK:
418     case S_IFCHR:
419     case S_IFIFO:
420       if (mknod(file_hdr->name, file_hdr->mode, file_hdr->device))
421         perror_msg("can't create '%s'", file_hdr->name);
422       break;
423     default:
424       printf("type not yet supported\n");
425       break;
426   }
427 
428   //copy file....
429 COPY:
430   copy_in_out(tar->src_fd, dst_fd, file_hdr->size);
431   tar->offset += file_hdr->size;
432   close(dst_fd);
433 
434   if (S_ISLNK(file_hdr->mode)) return;
435   if (!(toys.optflags & FLAG_o)) {
436     //set ownership..., --no-same-owner, --numeric-owner
437     uid_t u = file_hdr->uid;
438     gid_t g = file_hdr->gid;
439 
440     if (!(toys.optflags & FLAG_numeric_owner)) {
441       struct group *gr = getgrnam(file_hdr->gname);
442       struct passwd *pw = getpwnam(file_hdr->uname);
443       if (pw) u = pw->pw_uid;
444       if (gr) g = gr->gr_gid;
445     }
446     if (chown(file_hdr->name, u, g))
447       perror_msg("chown %d:%d '%s'", u, g, file_hdr->name);;
448   }
449 
450   if (toys.optflags & FLAG_p) // || !(toys.optflags & FLAG_no_same_permissions))
451     chmod(file_hdr->name, file_hdr->mode);
452 
453   //apply mtime
454   if (!(toys.optflags & FLAG_m)) {
455     struct timeval times[2] = {{file_hdr->mtime, 0},{file_hdr->mtime, 0}};
456     utimes(file_hdr->name, times);
457   }
458 }
459 
add_to_list(struct arg_list ** llist,char * name)460 static void add_to_list(struct arg_list **llist, char *name)
461 {
462   struct arg_list **list = llist;
463 
464   while (*list) list=&((*list)->next);
465   *list = xzalloc(sizeof(struct arg_list));
466   (*list)->arg = name;
467   if ((name[strlen(name)-1] == '/') && strlen(name) != 1)
468     name[strlen(name)-1] = '\0';
469 }
470 
add_from_file(struct arg_list ** llist,struct arg_list * flist)471 static void add_from_file(struct arg_list **llist, struct arg_list *flist)
472 {
473   char *line = NULL;
474 
475   while (flist) {
476     int fd = 0;
477 
478     if (strcmp((char *)flist->arg, "-"))
479       fd = xopen((char *)flist->arg, O_RDONLY);
480 
481     while ((line = get_line(fd))) {
482       add_to_list(llist, line);
483     }
484     if (fd) close(fd);
485     flist = flist->next;
486   }
487 }
488 
init_handler()489 static struct archive_handler *init_handler()
490 {
491   struct archive_handler *tar_hdl = xzalloc(sizeof(struct archive_handler));
492   tar_hdl->extract_handler = extract_to_disk;
493   return tar_hdl;
494 }
495 
496 //convert octal to int
otoi(char * str,int len)497 static int otoi(char *str, int len)
498 {
499   long val;
500   char *endp, inp[len+1]; //1 for NUL termination
501 
502   memcpy(inp, str, len);
503   inp[len] = '\0'; //nul-termination made sure
504   val = strtol(inp, &endp, 8);
505   if (*endp && *endp != ' ') error_exit("invalid param");
506   return (int)val;
507 }
508 
extract_stream(struct archive_handler * tar_hdl)509 static void extract_stream(struct archive_handler *tar_hdl)
510 {
511   int pipefd[2];
512   pid_t cpid;
513 
514   xpipe(pipefd);
515 
516   cpid = fork();
517   if (cpid == -1) perror_exit("fork");
518 
519   if (!cpid) {    /* Child reads from pipe */
520     char *argv[] =
521       {(toys.optflags&FLAG_z)?"gunzip":"bunzip2", "-cf", "-", NULL};
522     xclose(pipefd[0]); /* Close unused read*/
523     dup2(tar_hdl->src_fd, 0);
524     dup2(pipefd[1], 1); //write to pipe
525     xexec(argv);
526   } else {
527     xclose(pipefd[1]);          /* Close unused read end */
528     dup2(pipefd[0], tar_hdl->src_fd); //read from pipe
529   }
530 }
531 
process_extended_hdr(struct archive_handler * tar,int size)532 static char *process_extended_hdr(struct archive_handler *tar, int size)
533 {
534   char *value = NULL, *p, *buf = xzalloc(size+1);
535 
536   if (readall(tar->src_fd, buf, size) != size) error_exit("short read");
537   buf[size] = 0;
538   tar->offset += size;
539   p = buf;
540 
541   while (size) {
542     char *key;
543     int len, n;
544 
545     // extended records are of the format: "LEN NAME=VALUE\n"
546     sscanf(p, "%d %n", &len, &n);
547     key = p + n;
548     p += len;
549     size -= len;
550     p[-1] = 0;
551     if (size < 0) {
552       error_msg("corrupted extended header");
553       break;
554     }
555 
556     len = strlen("path=");
557     if (!strncmp(key, "path=", len)) {
558       value = key + strlen("path=");
559       break;
560     }
561   }
562   if (value) value = xstrdup(value);
563   free(buf);
564   return value;
565 }
566 
tar_skip(struct archive_handler * tar,int sz)567 static void tar_skip(struct archive_handler *tar, int sz)
568 {
569   int x;
570 
571   while ((x = lskip(tar->src_fd, sz))) {
572     tar->offset += sz - x;
573     sz = x;
574   }
575   tar->offset += sz;
576 }
577 
unpack_tar(struct archive_handler * tar_hdl)578 static void unpack_tar(struct archive_handler *tar_hdl)
579 {
580   struct tar_hdr tar;
581   struct file_header *file_hdr;
582   int i, j, maj, min, sz, e = 0;
583   unsigned int cksum;
584   char *longname = NULL, *longlink = NULL;
585 
586   while (1) {
587     cksum = 0;
588     if (tar_hdl->offset % 512) {
589       sz = 512 - tar_hdl->offset % 512;
590       tar_skip(tar_hdl, sz);
591     }
592     i = readall(tar_hdl->src_fd, &tar, 512);
593     tar_hdl->offset += i;
594     if (i != 512) {
595       if (i >= 2) goto CHECK_MAGIC; //may be a small (<512 byte)zipped file
596       error_exit("read error");
597     }
598 
599     if (!tar.name[0]) {
600       if (e) return; //end of tar 2 empty blocks
601       e = 1;//empty jump to next block
602       continue;
603     }
604     if (strncmp(tar.magic, "ustar", 5)) {
605       // Try detecting .gz or .bz2 by looking for their magic.
606 CHECK_MAGIC:
607       if ((!strncmp(tar.name, "\x1f\x8b", 2) || !strncmp(tar.name, "BZh", 3))
608           && !lseek(tar_hdl->src_fd, -i, SEEK_CUR)) {
609         toys.optflags |= (*tar.name == 'B') ? FLAG_j : FLAG_z;
610         tar_hdl->offset -= i;
611         extract_stream(tar_hdl);
612         continue;
613       }
614       error_exit("invalid tar format");
615     }
616 
617     for (j = 0; j<148; j++) cksum += (unsigned int)((char*)&tar)[j];
618     for (j = 156; j<500; j++) cksum += (unsigned int)((char*)&tar)[j];
619     //cksum field itself treated as ' '
620     for ( j= 0; j<8; j++) cksum += (unsigned int)' ';
621 
622     if (cksum != otoi(tar.chksum, sizeof(tar.chksum))) error_exit("wrong cksum");
623 
624     file_hdr = &tar_hdl->file_hdr;
625     memset(file_hdr, 0, sizeof(struct file_header));
626     file_hdr->mode = otoi(tar.mode, sizeof(tar.mode));
627     file_hdr->uid = otoi(tar.uid, sizeof(tar.uid));
628     file_hdr->gid = otoi(tar.gid, sizeof(tar.gid));
629     file_hdr->size = otoi(tar.size, sizeof(tar.size));
630     file_hdr->mtime = otoi(tar.mtime, sizeof(tar.mtime));
631     file_hdr->uname = xstrdup(tar.uname);
632     file_hdr->gname = xstrdup(tar.gname);
633     maj = otoi(tar.major, sizeof(tar.major));
634     min = otoi(tar.minor, sizeof(tar.minor));
635     file_hdr->device = dev_makedev(maj, min);
636 
637     if (tar.type <= '7') {
638       if (tar.link[0]) {
639         sz = sizeof(tar.link);
640         file_hdr->link_target = xmalloc(sz + 1);
641         memcpy(file_hdr->link_target, tar.link, sz);
642         file_hdr->link_target[sz] = '\0';
643       }
644 
645       file_hdr->name = xzalloc(256);// pathname supported size
646       if (tar.prefix[0]) {
647         memcpy(file_hdr->name, tar.prefix, sizeof(tar.prefix));
648         sz = strlen(file_hdr->name);
649         if (file_hdr->name[sz-1] != '/') file_hdr->name[sz] = '/';
650       }
651       sz = strlen(file_hdr->name);
652       memcpy(file_hdr->name + sz, tar.name, sizeof(tar.name));
653       if (file_hdr->name[255]) error_exit("filename too long");
654     }
655 
656     switch (tar.type) {
657       //    case '\0':
658       case '0':
659       case '7':
660       case '1': //Hard Link
661         file_hdr->mode |= S_IFREG;
662         break;
663       case '2':
664         file_hdr->mode |= S_IFLNK;
665         break;
666       case '3':
667         file_hdr->mode |= S_IFCHR;
668         break;
669       case '4':
670         file_hdr->mode |= S_IFBLK;
671         break;
672       case '5':
673         file_hdr->mode |= S_IFDIR;
674         break;
675       case '6':
676         file_hdr->mode |= S_IFIFO;
677         break;
678       case 'K':
679         longlink = xzalloc(file_hdr->size +1);
680         xread(tar_hdl->src_fd, longlink, file_hdr->size);
681         tar_hdl->offset += file_hdr->size;
682         continue;
683       case 'L':
684         free(longname);
685         longname = xzalloc(file_hdr->size +1);
686         xread(tar_hdl->src_fd, longname, file_hdr->size);
687         tar_hdl->offset += file_hdr->size;
688         continue;
689       case 'D':
690       case 'M':
691       case 'N':
692       case 'S':
693       case 'V':
694       case 'g':  // pax global header
695         tar_skip(tar_hdl, file_hdr->size);
696         continue;
697       case 'x':  // pax extended header
698         free(longname);
699         longname = process_extended_hdr(tar_hdl, file_hdr->size);
700         continue;
701       default: break;
702     }
703 
704     if (longname) {
705       free(file_hdr->name);
706       file_hdr->name = longname;
707       longname = NULL;
708     }
709     if (longlink) {
710       free(file_hdr->link_target);
711       file_hdr->link_target = longlink;
712       longlink = NULL;
713     }
714 
715     if ((file_hdr->mode & S_IFREG) &&
716         file_hdr->name[strlen(file_hdr->name)-1] == '/') {
717       file_hdr->name[strlen(file_hdr->name)-1] = '\0';
718       file_hdr->mode &= ~S_IFREG;
719       file_hdr->mode |= S_IFDIR;
720     }
721 
722     if ((file_hdr->link_target && *(file_hdr->link_target))
723         || S_ISLNK(file_hdr->mode) || S_ISDIR(file_hdr->mode))
724       file_hdr->size = 0;
725 
726     if (filter(TT.exc, file_hdr->name) ||
727         (TT.inc && !filter(TT.inc, file_hdr->name))) goto SKIP;
728     add_to_list(&TT.pass, xstrdup(file_hdr->name));
729 
730     if (toys.optflags & FLAG_t) {
731       if (toys.optflags & FLAG_v) {
732         char perm[11];
733         struct tm *lc = localtime((const time_t*)&(file_hdr->mtime));
734 
735         mode_to_string(file_hdr->mode, perm);
736         printf("%s %s/%s %9ld %d-%02d-%02d %02d:%02d:%02d ",perm,file_hdr->uname,
737             file_hdr->gname, (long)file_hdr->size, 1900+lc->tm_year,
738             1+lc->tm_mon, lc->tm_mday, lc->tm_hour, lc->tm_min, lc->tm_sec);
739       }
740       printf("%s",file_hdr->name);
741       if (file_hdr->link_target) printf(" -> %s",file_hdr->link_target);
742       xputc('\n');
743 SKIP:
744       tar_skip(tar_hdl, file_hdr->size);
745     } else {
746       if (toys.optflags & FLAG_v) printf("%s\n",file_hdr->name);
747       tar_hdl->extract_handler(tar_hdl);
748     }
749     free(file_hdr->name);
750     free(file_hdr->link_target);
751     free(file_hdr->uname);
752     free(file_hdr->gname);
753   }
754 }
755 
tar_main(void)756 void tar_main(void)
757 {
758   struct archive_handler *tar_hdl;
759   int fd = 0;
760   struct arg_list *tmp;
761   char **args = toys.optargs;
762 
763   if (!geteuid()) toys.optflags |= FLAG_p;
764 
765   for (tmp = TT.exc; tmp; tmp = tmp->next)
766     tmp->arg = xstrdup(tmp->arg); //freeing at the end fails otherwise
767 
768   while(*args) add_to_list(&TT.inc, xstrdup(*args++));
769   if (toys.optflags & FLAG_X) add_from_file(&TT.exc, TT.exc_file);
770   if (toys.optflags & FLAG_T) add_from_file(&TT.inc, TT.inc_file);
771 
772   if (toys.optflags & FLAG_c) {
773     if (!TT.inc) error_exit("empty archive");
774     fd = 1;
775   }
776   if ((toys.optflags & FLAG_f) && strcmp(TT.fname, "-"))
777     fd = xcreate(TT.fname, fd*(O_WRONLY|O_CREAT|O_TRUNC), 0666);
778   if (toys.optflags & FLAG_C) xchdir(TT.dir);
779 
780   tar_hdl = init_handler();
781   tar_hdl->src_fd = fd;
782 
783   if ((toys.optflags & FLAG_x) || (toys.optflags & FLAG_t)) {
784     if (toys.optflags & FLAG_O) tar_hdl->extract_handler = extract_to_stdout;
785     if (toys.optflags & FLAG_to_command) {
786       signal(SIGPIPE, SIG_IGN); //will be using pipe between child & parent
787       tar_hdl->extract_handler = extract_to_command;
788     }
789     if (toys.optflags & FLAG_z) extract_stream(tar_hdl);
790     unpack_tar(tar_hdl);
791     for (tmp = TT.inc; tmp; tmp = tmp->next)
792       if (!filter(TT.exc, tmp->arg) && !filter(TT.pass, tmp->arg))
793         error_msg("'%s' not in archive", tmp->arg);
794   } else if (toys.optflags & FLAG_c) {
795     //create the tar here.
796     if (toys.optflags & (FLAG_j|FLAG_z)) compress_stream(tar_hdl);
797     for (tmp = TT.inc; tmp; tmp = tmp->next) {
798       TT.handle = tar_hdl;
799       //recurse thru dir and add files to archive
800       dirtree_flagread(tmp->arg, DIRTREE_SYMFOLLOW*!!(toys.optflags&FLAG_h),
801         add_to_tar);
802     }
803     memset(toybuf, 0, 1024);
804     writeall(tar_hdl->src_fd, toybuf, 1024);
805     seen_inode(&TT.inodes, 0, 0);
806   }
807 
808   if (CFG_TOYBOX_FREE) {
809     close(tar_hdl->src_fd);
810     free(tar_hdl);
811     llist_traverse(TT.exc, llist_free_arg);
812     llist_traverse(TT.inc, llist_free_arg);
813     llist_traverse(TT.pass, llist_free_arg);
814   }
815 }
816