--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/toys/posix/cpio.c	Tue Mar 25 07:35:56 2014 -0500
@@ -0,0 +1,213 @@
+/* cpio.c - a basic cpio
+ *
+ * Written 2013 AD by Isaac Dunham; this code is placed under the 
+ * same license as toybox or as CC0, at your option.
+ *
+ * http://refspecs.linuxfoundation.org/LSB_4.1.0/LSB-Core-generic/LSB-Core-generic/cpio.html
+ * and http://pubs.opengroup.org/onlinepubs/7908799/xcu/cpio.html
+ *
+ * Yes, that's SUSv2, the newer standards removed it around the time RPM
+ * and initramfs started heavily using this archive format.
+ *
+ * Modern cpio expanded header to 110 bytes (first field 6 bytes, rest are 8).
+ * In order: magic ino mode uid gid nlink mtime filesize devmajor devminor
+ * rdevmajor rdevminor namesize check
+
+USE_CPIO(NEWTOY(cpio, "duH:i|t|F:o|v(verbose)[!io][!ot]", TOYFLAG_BIN))
+
+config CPIO
+  bool "cpio"
+  default y
+  help
+    usage: cpio -{o|t|i} [-v] [--verbose] [-F FILE] [ignored: -du -H newc]
+
+    copy files into and out of a "newc" format cpio archive
+
+    -F FILE	use archive FILE instead of stdin/stdout
+    -i	extract from archive into file system (stdin=archive)
+    -o	create archive (stdin=list of files, stdout=archive)
+    -t	test files (list only, stdin=archive, stdout=list of files)
+    -v	verbose (list files during create/extract)
+*/
+
+#define FOR_cpio
+#include "toys.h"
+
+GLOBALS(
+  char *archive;
+  char *fmt;
+)
+
+// Read strings, tail padded to 4 byte alignment. Argument "align" is amount
+// by which start of string isn't aligned (usually 0).
+static char *strpad(int fd, unsigned len, unsigned align)
+{
+  char *str;
+
+  align = (align + len) & 3;
+  if (align) len += (4-align);
+
+  xreadall(fd, str = xmalloc(len+1), len);
+  str[len]=0; // redundant, in case archive is bad
+
+  return str;
+}
+
+//convert hex to uint; mostly to allow using bits of non-terminated strings
+unsigned x8u(char *hex)
+{
+  unsigned val, inpos = 8, outpos;
+  char pattern[6];
+
+  while (*hex == '0') {
+    hex++;
+    if (!--inpos) return 0;
+  }
+  // Because scanf gratuitously treats %*X differently than printf does.
+  sprintf(pattern, "%%%dX%%n", inpos);
+  sscanf(hex, pattern, &val, &outpos);
+  if (inpos != outpos) error_exit("bad header");
+
+  return val;
+}
+
+void cpio_main(void)
+{
+  int afd;
+
+  // Subtle bit: FLAG_o is 1 so we can just use it to select stdin/stdout.
+
+  afd = toys.optflags & FLAG_o;
+  if (TT.archive) {
+    int perm = (toys.optflags & FLAG_o) ? O_CREAT|O_WRONLY|O_TRUNC : O_RDONLY;
+
+    afd = xcreate(TT.archive, perm, 0644);
+  }
+
+  // read cpio archive
+
+  if (toys.optflags & (FLAG_i|FLAG_t)) for (;;) {
+    char *name, *tofree, *data;
+    unsigned size, mode;
+    int test = toys.optflags & FLAG_t, err = 0;
+
+    // Read header and name.
+    xreadall(afd, toybuf, 110);
+    tofree = name = strpad(afd, x8u(toybuf+94), 110);
+    if (!strcmp("TRAILER!!!", name)) break;
+
+    // If you want to extract absolute paths, "cd /" and run cpio.
+    while (*name == '/') name++;
+
+    // Align to 4 bytes. Note header is 110 bytes which is 2 bytes over.
+
+    size = x8u(toybuf+54);
+    mode = x8u(toybuf+14);
+
+    if (toys.optflags & (FLAG_t|FLAG_v)) puts(name);
+
+    if (!test && strrchr(name, '/') && mkpathat(AT_FDCWD, name, 0, 2)) {
+      perror_msg("mkpath '%s'", name);
+      test++;
+    }
+
+    // Consume entire record even if it couldn't create file, so we're
+    // properly aligned with next file.
+
+    if (S_ISDIR(mode)) {
+      if (!test) err = mkdir(name, mode);
+    } else if (S_ISLNK(mode)) {
+      data = strpad(afd, size, 0);
+      if (!test) err = symlink(data, name);
+    } else if (S_ISREG(mode)) {
+      int fd;
+
+      // If write fails, we still need to read/discard data to continue with
+      // archive. Since doing so overwrites errno, report error now
+      fd = test ? 0 : open(name, O_CREAT|O_WRONLY|O_TRUNC|O_NOFOLLOW, mode);
+      if (fd < 0) {
+        perror_msg("create %s", name);
+        test++;
+      }
+
+      data = toybuf;
+      while (size) {
+        if (size < sizeof(toybuf)) data = strpad(afd, size, 0);
+        else xreadall(afd, toybuf, sizeof(toybuf));
+        if (!test) xwrite(fd, data, data == toybuf ? sizeof(toybuf) : size);
+        if (data != toybuf) {
+          free(data);
+          break;
+        }
+        size -= sizeof(toybuf);
+      }
+      close(fd);
+    } else if (!test)
+      err = mknod(name, mode, makedev(x8u(toybuf+62), x8u(toybuf+70)));
+
+    if (err<0) perror_msg("create '%s'", name);
+    free(tofree);
+
+  // Output cpio archive
+
+  } else {
+    char *name = 0;
+    size_t size = 0;
+
+    for (;;) {
+      struct stat st;
+      unsigned nlen = strlen(name)+1, error = 0, zero = 0;
+      int len, fd = -1;
+      ssize_t llen;
+
+      len = getline(&name, &size, stdin);
+      if (len<1) break;
+      if (name[len-1] == '\n') name[--len] = 0;
+      if (lstat(name, &st)
+          || (S_ISREG(st.st_mode) && (fd = open(name, O_RDONLY))<0))
+      {
+        perror_msg("%s", name);
+        continue;
+      }
+
+      if (!S_ISREG(st.st_mode) && !S_ISLNK(st.st_mode)) st.st_size = 0;
+      if (st.st_size >> 32) perror_msg("skipping >2G file '%s'", name);
+      else {
+        llen = sprintf(toybuf,
+          "070701%08X%08X%08X%08X%08X%08X%08X%08X%08X%08X%08X%08X%08X",
+          (int)st.st_ino, st.st_mode, st.st_uid, st.st_gid, (int)st.st_nlink,
+          (int)st.st_mtime, (int)st.st_size, major(st.st_dev),
+          minor(st.st_dev), major(st.st_rdev), minor(st.st_rdev), nlen, 0);
+        xwrite(afd, toybuf, llen);
+        xwrite(afd, name, nlen);
+
+        // NUL Pad header up to 4 multiple bytes.
+        llen = (llen + nlen) & 3;
+        if (llen) xwrite(afd, &zero, 4-llen); 
+
+        // Write out body for symlink or regular file
+        llen = st.st_size;
+        if (S_ISLNK(st.st_mode)) {
+          if (readlink(name, toybuf, sizeof(toybuf)-1) == llen)
+            xwrite(afd, toybuf, llen);
+          else perror_msg("readlink '%s'", name);
+        } else while (llen) {
+          nlen = llen > sizeof(toybuf) ? sizeof(toybuf) : llen;
+          llen -= nlen;
+          // If read fails, write anyway (already wrote size in header)
+          if (nlen != readall(fd, toybuf, nlen))
+            if (!error++) perror_msg("bad read from file '%s'", name);
+          xwrite(afd, toybuf, nlen);
+        }
+        llen = st.st_size & 3;
+        if (llen) write(afd, &zero, 4-llen);
+      }
+      close(fd);
+    }
+    free(name);
+
+    xwrite(afd, toybuf,
+      sprintf(toybuf, "070701%040X%056X%08XTRAILER!!!%c%c%c",
+              1, 0x0b, 0, 0, 0, 0));
+  }
+}