changeset 1227:903acf85bd1d

Most of the remaining cpio cleanup.
author Rob Landley <rob@landley.net>
date Mon, 24 Mar 2014 08:19:21 -0500
parents e1b09affb6db
children 2366f9d73745
files toys/pending/cpio.c
diffstat 1 files changed, 165 insertions(+), 206 deletions(-) [+]
line wrap: on
line diff
--- a/toys/pending/cpio.c	Mon Mar 24 06:26:49 2014 -0500
+++ b/toys/pending/cpio.c	Mon Mar 24 08:19:21 2014 -0500
@@ -4,33 +4,30 @@
  * 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
  *
- * 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. Go figure.)
+ * 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, "H:di|o|t|uF:[!iot][!dot][!uot]", TOYFLAG_BIN))
+USE_CPIO(NEWTOY(cpio, "duH:i|t|F:o|v(verbose)[!io][!ot]", TOYFLAG_BIN))
 
 config CPIO
   bool "cpio"
   default n
   help
-    usage: cpio {-o|-t|-i[du]} [-H FMT] [-F ARCHIVE]
+    usage: cpio -{o|t|i} [-v] [--verbose] [-F FILE] [ignored: -du -H newc]
 
     copy files into and out of a "newc" format cpio archive
 
-    Actions:
-    -o	create archive (stdin is a list of files, stdout is an archive)
-    -t	list files (stdin is an archive, stdout is a list of files)
-    -i	extract from archive into file system (stdin is an archive)
-
-    Extract options:
-    -d	create leading directories when extracting an archive
-    -u	always overwrite files (default)
-
-    Other options:
-    -H FMT	archive format (ignored, only newc supported)
-    -F ARCHIVE	read from or write to ARCHIVE file
+    -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
@@ -39,213 +36,175 @@
 GLOBALS(
   char *archive;
   char *fmt;
-
-  int outfd;
 )
 
-// 110 bytes
-struct newc_header {
-  char    c_magic[6];
-  char    c_ino[8];
-  char    c_mode[8];
-  char    c_uid[8];
-  char    c_gid[8];
-  char    c_nlink[8];
-  char    c_mtime[8];
-  char    c_filesize[8];
-  char    c_devmajor[8];
-  char    c_devminor[8];
-  char    c_rdevmajor[8];
-  char    c_rdevminor[8];
-  char    c_namesize[8];
-  char    c_check[8];
-};
+// 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;
 
-void write_cpio_member(int fd, char *name, struct stat buf)
-{
-  unsigned nlen = strlen(name)+1, error = 0, zero = 0;
-  ssize_t llen;
+  align = (align + len) & 3;
+  if (align) len += (4-align);
 
-  if (!S_ISREG(buf.st_mode) && !S_ISLNK(buf.st_mode)) buf.st_size = 0;
-  else if (buf.st_size >> 32) {
-    perror_msg("skipping >2G file '%s'", name);
-    return;
-  }
+  xreadall(fd, str = xmalloc(len+1), len);
+  str[len]=0; // redundant, in case archive is bad
 
-  llen = sprintf(toybuf,
-    "070701%08X%08X%08X%08X%08X%08X%08X%08X%08X%08X%08X%08X%08X",
-    (int)(buf.st_ino), buf.st_mode, buf.st_uid, buf.st_gid, (int)buf.st_nlink,
-    (int)(buf.st_mtime), (int)(buf.st_size), major(buf.st_dev),
-    minor(buf.st_dev), major(buf.st_rdev), minor(buf.st_rdev), nlen, 0);
-  xwrite(TT.outfd, toybuf, llen);
-  xwrite(TT.outfd, name, nlen);
-
-  // NUL Pad header up to 4 multiple bytes.
-  llen = (llen + nlen) & 3;
-  if (llen) xwrite(TT.outfd, &zero, 4-llen); 
-
-  // Write out body for symlink or regular file
-  llen = buf.st_size;
-  if (S_ISLNK(buf.st_mode)) {
-    if (readlink(name, toybuf, sizeof(toybuf)-1) == llen)
-      xwrite(TT.outfd, toybuf, llen);
-    else perror_msg("readlink '%s'", name);
-  } else while (llen) {
-    nlen = llen > sizeof(toybuf) ? sizeof(toybuf) : llen;
-    // If read fails, write anyway (we already wrote size in the header).
-    if (nlen != readall(fd, toybuf, nlen))
-      if (!error++) perror_msg("bad read from file '%s'", name);
-    xwrite(TT.outfd, toybuf, nlen);
-  }
-  llen = buf.st_size & 3;
-  if (nlen) write(TT.outfd, &zero, 4-llen);
-}
-
-// Iterate through a list of files read from stdin. No users need rw.
-void loopfiles_stdin(void)
-{
-  char *name = 0;
-  size_t size = 0;
-
-  for (;;) {
-    struct stat st;
-    int len, fd;
-
-    len = getline(&name, &size, stdin);
-    if (!name) break;
-    if (name[len-1] == '\n') name[--len] = 0;
-    if (lstat(name, &st) || (fd = open(name, O_RDONLY))<0)
-      perror_msg("%s", name);
-    else {
-      write_cpio_member(fd, name, st);
-      close(fd);
-    }
-  }
-  free(name);
+  return str;
 }
 
 //convert hex to uint; mostly to allow using bits of non-terminated strings
-unsigned int htou(char * hex)
+unsigned x8u(char *hex)
 {
-  unsigned int ret = 0, i = 0;
+  unsigned val, inpos = 8, outpos;
+  char pattern[6];
 
-  for (;(i < 8 && hex[i]);) {
-     ret *= 16;
-     switch(hex[i]) { 
-     case '0':
-       break;
-     case '1': 
-     case '2': 
-     case '3': 
-     case '4': 
-     case '5': 
-     case '6': 
-     case '7': 
-     case '8': 
-     case '9': 
-       ret += hex[i] - '1' + 1;
-       break;
-     case 'A': 
-     case 'B': 
-     case 'C': 
-     case 'D': 
-     case 'E': 
-     case 'F': 
-       ret += hex[i] - 'A' + 10;
-       break;
-     }
-     i++;
+  while (*hex == '0') {
+    hex++;
+    if (!--inpos) return 0;
   }
-  return ret;
-}
+  // 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");
 
-// Read one cpio record. Returns 0 for last record, 1 for "continue".
-int read_cpio_member(int fd, int how)
-{
-  uint32_t nsize, fsize;
-  mode_t mode = 0;
-  int pad, ofd = 0; 
-  struct newc_header hdr;
-  char *name, *lastdir;
-  dev_t dev = 0;
-
-  xreadall(fd, &hdr, sizeof(struct newc_header));
-  nsize = htou(hdr.c_namesize);
-  xreadall(fd, name = xmalloc(nsize), nsize);
-  if (!strcmp("TRAILER!!!", name)) return 0;
-  fsize = htou(hdr.c_filesize);
-  mode += htou(hdr.c_mode);
-  pad = 4 - ((nsize + 2) % 4); // 2 == sizeof(struct newc_header) % 4
-  if (pad < 4) xreadall(fd, toybuf, pad);
-  pad = 4 - (fsize % 4);
-
-  if ((toys.optflags&FLAG_d) && (lastdir = strrchr(name, '/')))
-    if (mkpathat(AT_FDCWD, name, 0, 2)) perror_msg("mkpath '%s'", name);
-
-  if (how & 1) {
-    if (S_ISDIR(mode)) ofd = mkdir(name, mode);
-    else if (S_ISLNK(mode)) {
-      memset(toybuf, 0, sizeof(toybuf));
-      if (fsize < sizeof(toybuf)) {
-        pad = readall(fd, toybuf, fsize); 
-	if (pad < fsize) error_exit("short archive");
-	pad = 4 - (fsize % 4);
-	fsize = 0;
-        if (symlink(toybuf, name)) {
-	  perror_msg("could not write link %s", name);
-	  toys.exitval |= 1;
-	}
-      } else {
-        perror_msg("link too long: %s", name);
-	toys.exitval |= 1;
-      }
-    } else if (S_ISBLK(mode)||S_ISCHR(mode)||S_ISFIFO(mode)||S_ISSOCK(mode)) {
-      dev = makedev(htou(hdr.c_rdevmajor),htou(hdr.c_rdevminor));
-      ofd = mknod(name, mode, dev);
-    } else ofd = creat(name, mode);
-    if (ofd == -1) {
-      error_msg("could not create %s", name);
-      toys.exitval |= 1;
-    }
-  }
-  errno = 0;
-  if (how & 2) puts(name);
-  while (fsize) {
-    int i;
-    memset(toybuf, 0, sizeof(toybuf));
-    i = readall(fd, toybuf, (fsize>sizeof(toybuf)) ? sizeof(toybuf) : fsize);
-    if (i < 1) error_exit("archive too short");
-    if (ofd > 0) writeall(ofd, toybuf, i);
-    fsize -= i;
-  }
-  if (pad < 4) xreadall(fd, toybuf, pad);
-  return 1;
-}
-
-void read_cpio_archive(int fd, int how)
-{
-  for(;;) if (!read_cpio_member(fd, how)) return;
+  return val;
 }
 
 void cpio_main(void)
 {
-  TT.outfd = 1;
+  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) {
-    if (toys.optflags & (FLAG_i|FLAG_t)) {
-      xclose(0);
-      xopen(TT.archive, O_RDONLY);
-    } else if (toys.optflags & FLAG_o) {
-      xclose(1);
-      xcreate(TT.archive, O_CREAT|O_WRONLY|O_TRUNC, 0644);
-    }
+    int perm = (toys.optflags & FLAG_o) ? O_CREAT|O_WRONLY|O_TRUNC : O_RDONLY;
+
+    afd = xcreate(TT.archive, perm, 0644);
   }
 
-  if (toys.optflags & FLAG_t) read_cpio_archive(0, 2);
-  else if (toys.optflags & FLAG_i) read_cpio_archive(0, 1);
-  else if (toys.optflags & FLAG_o) {
-      loopfiles_stdin();
-      write(1, "07070100000000000000000000000000000000000000010000000000000000"
-      "000000000000000000000000000000000000000B00000000TRAILER!!!\0\0\0", 124);
-  } else error_exit("must use one of -iot");
+  // 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;
+      ssize_t llen;
+
+      len = getline(&name, &size, stdin);
+      if (len<1) break;
+      if (name[len-1] == '\n') name[--len] = 0;
+      if (lstat(name, &st) || (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;
+          // 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 (nlen) 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));
+  }
 }