coreutils-8.25HEADcoreutils-8.25master

1 files changed, 398 insertions, 0 deletions

diff --git a/src/truncate.c b/src/truncate.c
new file mode 100644
index 0000000..0dff840
--- /dev/null
+++ b/src/truncate.c
@@ -0,0 +1,398 @@
+/* truncate -- truncate or extend the length of files.
+   Copyright (C) 2008-2016 Free Software Foundation, Inc.
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+/* Written by Pádraig Brady
+
+   This is backwards compatible with the FreeBSD utility, but is more
+   flexible wrt the size specifications and the use of long options,
+   to better fit the "GNU" environment.  */
+
+#include <config.h>             /* sets _FILE_OFFSET_BITS=64 etc. */
+#include <stdio.h>
+#include <getopt.h>
+#include <sys/types.h>
+
+#include "system.h"
+#include "error.h"
+#include "quote.h"
+#include "stat-size.h"
+#include "xdectoint.h"
+
+/* The official name of this program (e.g., no 'g' prefix).  */
+#define PROGRAM_NAME "truncate"
+
+#define AUTHORS proper_name_utf8 ("Padraig Brady", "P\303\241draig Brady")
+
+/* (-c) If true, don't create if not already there */
+static bool no_create;
+
+/* (-o) If true, --size refers to blocks not bytes */
+static bool block_mode;
+
+/* (-r) Reference file to use size from */
+static char const *ref_file;
+
+static struct option const longopts[] =
+{
+  {"no-create", no_argument, NULL, 'c'},
+  {"io-blocks", no_argument, NULL, 'o'},
+  {"reference", required_argument, NULL, 'r'},
+  {"size", required_argument, NULL, 's'},
+  {GETOPT_HELP_OPTION_DECL},
+  {GETOPT_VERSION_OPTION_DECL},
+  {NULL, 0, NULL, 0}
+};
+
+typedef enum
+{ rm_abs = 0, rm_rel, rm_min, rm_max, rm_rdn, rm_rup } rel_mode_t;
+
+void
+usage (int status)
+{
+  if (status != EXIT_SUCCESS)
+    emit_try_help ();
+  else
+    {
+      printf (_("Usage: %s OPTION... FILE...\n"), program_name);
+      fputs (_("\
+Shrink or extend the size of each FILE to the specified size\n\
+\n\
+A FILE argument that does not exist is created.\n\
+\n\
+If a FILE is larger than the specified size, the extra data is lost.\n\
+If a FILE is shorter, it is extended and the extended part (hole)\n\
+reads as zero bytes.\n\
+"), stdout);
+
+      emit_mandatory_arg_note ();
+
+      fputs (_("\
+  -c, --no-create        do not create any files\n\
+"), stdout);
+      fputs (_("\
+  -o, --io-blocks        treat SIZE as number of IO blocks instead of bytes\n\
+"), stdout);
+      fputs (_("\
+  -r, --reference=RFILE  base size on RFILE\n\
+  -s, --size=SIZE        set or adjust the file size by SIZE bytes\n"), stdout);
+      fputs (HELP_OPTION_DESCRIPTION, stdout);
+      fputs (VERSION_OPTION_DESCRIPTION, stdout);
+      emit_size_note ();
+      fputs (_("\n\
+SIZE may also be prefixed by one of the following modifying characters:\n\
+'+' extend by, '-' reduce by, '<' at most, '>' at least,\n\
+'/' round down to multiple of, '%' round up to multiple of.\n"), stdout);
+      emit_ancillary_info (PROGRAM_NAME);
+    }
+  exit (status);
+}
+
+/* return true on success, false on error.  */
+static bool
+do_ftruncate (int fd, char const *fname, off_t ssize, off_t rsize,
+              rel_mode_t rel_mode)
+{
+  struct stat sb;
+  off_t nsize;
+
+  if ((block_mode || (rel_mode && rsize < 0)) && fstat (fd, &sb) != 0)
+    {
+      error (0, errno, _("cannot fstat %s"), quoteaf (fname));
+      return false;
+    }
+  if (block_mode)
+    {
+      off_t const blksize = ST_BLKSIZE (sb);
+      if (ssize < OFF_T_MIN / blksize || ssize > OFF_T_MAX / blksize)
+        {
+          error (0, 0,
+                 _("overflow in %" PRIdMAX
+                   " * %" PRIdMAX " byte blocks for file %s"),
+                 (intmax_t) ssize, (intmax_t) blksize,
+                 quoteaf (fname));
+          return false;
+        }
+      ssize *= blksize;
+    }
+  if (rel_mode)
+    {
+      uintmax_t fsize;
+
+      if (0 <= rsize)
+        fsize = rsize;
+      else
+        {
+          off_t file_size;
+          if (usable_st_size (&sb))
+            {
+              file_size = sb.st_size;
+              if (file_size < 0)
+                {
+                  /* Sanity check.  Overflow is the only reason I can think
+                     this would ever go negative. */
+                  error (0, 0, _("%s has unusable, apparently negative size"),
+                         quoteaf (fname));
+                  return false;
+                }
+            }
+          else
+            {
+              file_size = lseek (fd, 0, SEEK_END);
+              if (file_size < 0)
+                {
+                  error (0, errno, _("cannot get the size of %s"),
+                         quoteaf (fname));
+                  return false;
+                }
+            }
+          fsize = file_size;
+        }
+
+      if (rel_mode == rm_min)
+        nsize = MAX (fsize, (uintmax_t) ssize);
+      else if (rel_mode == rm_max)
+        nsize = MIN (fsize, (uintmax_t) ssize);
+      else if (rel_mode == rm_rdn)
+        /* 0..ssize-1 -> 0 */
+        nsize = (fsize / ssize) * ssize;
+      else if (rel_mode == rm_rup)
+        /* 1..ssize -> ssize */
+        {
+          /* Here ssize>=1 && fsize>=0 */
+          uintmax_t const overflow = ((fsize + ssize - 1) / ssize) * ssize;
+          if (overflow > OFF_T_MAX)
+            {
+              error (0, 0, _("overflow rounding up size of file %s"),
+                     quoteaf (fname));
+              return false;
+            }
+          nsize = overflow;
+        }
+      else
+        {
+          if (ssize > OFF_T_MAX - (off_t)fsize)
+            {
+              error (0, 0, _("overflow extending size of file %s"),
+                     quoteaf (fname));
+              return false;
+            }
+          nsize = fsize + ssize;
+        }
+    }
+  else
+    nsize = ssize;
+  if (nsize < 0)
+    nsize = 0;
+
+  if (ftruncate (fd, nsize) == -1)      /* note updates mtime & ctime */
+    {
+      error (0, errno,
+             _("failed to truncate %s at %" PRIdMAX " bytes"), quoteaf (fname),
+             (intmax_t) nsize);
+      return false;
+    }
+
+  return true;
+}
+
+int
+main (int argc, char **argv)
+{
+  bool got_size = false;
+  bool errors = false;
+  off_t size IF_LINT ( = 0);
+  off_t rsize = -1;
+  rel_mode_t rel_mode = rm_abs;
+  int c, fd = -1, oflags;
+  char const *fname;
+
+  initialize_main (&argc, &argv);
+  set_program_name (argv[0]);
+  setlocale (LC_ALL, "");
+  bindtextdomain (PACKAGE, LOCALEDIR);
+  textdomain (PACKAGE);
+
+  atexit (close_stdout);
+
+  while ((c = getopt_long (argc, argv, "cor:s:", longopts, NULL)) != -1)
+    {
+      switch (c)
+        {
+        case 'c':
+          no_create = true;
+          break;
+
+        case 'o':
+          block_mode = true;
+          break;
+
+        case 'r':
+          ref_file = optarg;
+          break;
+
+        case 's':
+          /* skip any whitespace */
+          while (isspace (to_uchar (*optarg)))
+            optarg++;
+          switch (*optarg)
+            {
+            case '<':
+              rel_mode = rm_max;
+              optarg++;
+              break;
+            case '>':
+              rel_mode = rm_min;
+              optarg++;
+              break;
+            case '/':
+              rel_mode = rm_rdn;
+              optarg++;
+              break;
+            case '%':
+              rel_mode = rm_rup;
+              optarg++;
+              break;
+            }
+          /* skip any whitespace */
+          while (isspace (to_uchar (*optarg)))
+            optarg++;
+          if (*optarg == '+' || *optarg == '-')
+            {
+              if (rel_mode)
+                {
+                  error (0, 0, _("multiple relative modifiers specified"));
+                  /* Note other combinations are flagged as invalid numbers */
+                  usage (EXIT_FAILURE);
+                }
+              rel_mode = rm_rel;
+            }
+          /* Support dd BLOCK size suffixes + lowercase g,t,m for bsd compat.
+             Note we don't support dd's b=512, c=1, w=2 or 21x512MiB formats. */
+          size = xdectoimax (optarg, OFF_T_MIN, OFF_T_MAX, "EgGkKmMPtTYZ0",
+                             _("Invalid number"), 0);
+          /* Rounding to multiple of 0 is nonsensical */
+          if ((rel_mode == rm_rup || rel_mode == rm_rdn) && size == 0)
+            error (EXIT_FAILURE, 0, _("division by zero"));
+          got_size = true;
+          break;
+
+        case_GETOPT_HELP_CHAR;
+
+        case_GETOPT_VERSION_CHAR (PROGRAM_NAME, AUTHORS);
+
+        default:
+          usage (EXIT_FAILURE);
+        }
+    }
+
+  argv += optind;
+  argc -= optind;
+
+  /* must specify either size or reference file */
+  if (!ref_file && !got_size)
+    {
+      error (0, 0, _("you must specify either %s or %s"),
+             quote_n (0, "--size"), quote_n (1, "--reference"));
+      usage (EXIT_FAILURE);
+    }
+  /* must specify a relative size with a reference file */
+  if (ref_file && got_size && !rel_mode)
+    {
+      error (0, 0, _("you must specify a relative %s with %s"),
+             quote_n (0, "--size"), quote_n (1, "--reference"));
+      usage (EXIT_FAILURE);
+    }
+  /* block_mode without size is not valid */
+  if (block_mode && !got_size)
+    {
+      error (0, 0, _("%s was specified but %s was not"),
+             quote_n (0, "--io-blocks"), quote_n (1, "--size"));
+      usage (EXIT_FAILURE);
+    }
+  /* must specify at least 1 file */
+  if (argc < 1)
+    {
+      error (0, 0, _("missing file operand"));
+      usage (EXIT_FAILURE);
+    }
+
+  if (ref_file)
+    {
+      struct stat sb;
+      off_t file_size = -1;
+      if (stat (ref_file, &sb) != 0)
+        error (EXIT_FAILURE, errno, _("cannot stat %s"), quoteaf (ref_file));
+      if (usable_st_size (&sb))
+        file_size = sb.st_size;
+      else
+        {
+          int ref_fd = open (ref_file, O_RDONLY);
+          if (0 <= ref_fd)
+            {
+              off_t file_end = lseek (ref_fd, 0, SEEK_END);
+              int saved_errno = errno;
+              close (ref_fd); /* ignore failure */
+              if (0 <= file_end)
+                file_size = file_end;
+              else
+                {
+                  /* restore, in case close clobbered it. */
+                  errno = saved_errno;
+                }
+            }
+        }
+      if (file_size < 0)
+        error (EXIT_FAILURE, errno, _("cannot get the size of %s"),
+               quoteaf (ref_file));
+      if (!got_size)
+        size = file_size;
+      else
+        rsize = file_size;
+    }
+
+  oflags = O_WRONLY | (no_create ? 0 : O_CREAT) | O_NONBLOCK;
+
+  while ((fname = *argv++) != NULL)
+    {
+      if ((fd = open (fname, oflags, MODE_RW_UGO)) == -1)
+        {
+          /* 'truncate -s0 -c no-such-file'  shouldn't gen error
+             'truncate -s0 no-such-dir/file' should gen ENOENT error
+             'truncate -s0 no-such-dir/' should gen EISDIR error
+             'truncate -s0 .' should gen EISDIR error */
+          if (!(no_create && errno == ENOENT))
+            {
+              error (0, errno, _("cannot open %s for writing"),
+                     quoteaf (fname));
+              errors = true;
+            }
+          continue;
+        }
+
+
+      if (fd != -1)
+        {
+          errors |= !do_ftruncate (fd, fname, size, rsize, rel_mode);
+          if (close (fd) != 0)
+            {
+              error (0, errno, _("failed to close %s"), quoteaf (fname));
+              errors = true;
+            }
+        }
+    }
+
+  return errors ? EXIT_FAILURE : EXIT_SUCCESS;
+}