System-dependent functions
This commit is contained in:
Sergey Poznyakoff
633
src/system.c
Normal file
633
src/system.c
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@@ -0,0 +1,633 @@
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/* System-dependent calls for tar.
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Copyright (C) 2003 Free Software Foundation, Inc.
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This program is free software; you can redistribute it and/or modify it
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under the terms of the GNU General Public License as published by the
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Free Software Foundation; either version 2, or (at your option) any later
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version.
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This program is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
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Public License for more details.
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You should have received a copy of the GNU General Public License along
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with this program; if not, write to the Free Software Foundation, Inc.,
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59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
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#include "system.h"
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#include "common.h"
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#include "rmt.h"
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#if MSDOS
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bool
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sys_get_archive_stat ()
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{
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return 0;
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}
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bool
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sys_file_is_archive (struct tar_stat_info *p)
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{
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return false;
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}
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void
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sys_save_archive_dev_ino ()
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{
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}
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void
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sys_detect_dev_null_output ()
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{
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static char const dev_null[] = "nul";
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dev_null_output = (strcmp (archive_name_array[0], dev_null) == 0
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|| (! _isrmt (archive)));
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}
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void
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sys_drain_input_pipe ()
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{
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}
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void
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sys_wait_for_child (pid_t child_pid)
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{
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}
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void
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sys_spawn_shell ()
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{
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spawnl (P_WAIT, getenv ("COMSPEC"), "-", 0);
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}
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void
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sys_compare_uid_gid (struct stat *a, struct stat *b)
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{
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/* stat() in djgpp's C library gives a constant number of 42 as the
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uid and gid of a file. So, comparing an FTP'ed archive just after
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unpack would fail on MSDOS. */
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}
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void
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sys_compare_links (struct stat *link_data, struct stat *stat_data)
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{
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}
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int
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sys_truncate (int fd)
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{
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return write (fd, "", 0);
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}
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void
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sys_reset_uid_gid ()
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{
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}
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ssize_t
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sys_write_archive_buffer (void)
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{
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ssize_t status;
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ssize_t written = 0;
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while (0 <= (status = full_write (archive, record_start->buffer + written,
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record_size - written)))
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{
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written += status;
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if (written == record_size)
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break;
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}
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return written ? written : status;
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}
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/* Set ARCHIVE for writing, then compressing an archive. */
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void
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sys_child_open_for_compress (void)
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{
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FATAL_ERROR ((0, 0, _("Cannot use compressed or remote archives")));
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}
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/* Set ARCHIVE for uncompressing, then reading an archive. */
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void
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sys_child_open_for_uncompress (void)
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{
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FATAL_ERROR ((0, 0, _("Cannot use compressed or remote archives")));
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}
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#else
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extern union block *record_start; /* FIXME */
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static struct stat archive_stat; /* stat block for archive file */
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bool
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sys_get_archive_stat ()
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{
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return fstat (archive, &archive_stat) == 0;
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}
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bool
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sys_file_is_archive (struct tar_stat_info *p)
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{
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return (ar_dev && p->stat.st_dev == ar_dev && p->stat.st_ino == ar_ino);
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}
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/* Save archive file inode and device numbers */
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void
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sys_save_archive_dev_ino ()
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{
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if (!_isrmt (archive) && S_ISREG (archive_stat.st_mode))
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{
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ar_dev = archive_stat.st_dev;
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ar_ino = archive_stat.st_ino;
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}
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else
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ar_dev = 0;
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}
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/* Detect if outputting to "/dev/null". */
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void
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sys_detect_dev_null_output ()
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{
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static char const dev_null[] = "/dev/null";
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struct stat dev_null_stat;
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dev_null_output = (strcmp (archive_name_array[0], dev_null) == 0
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|| (! _isrmt (archive)
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&& S_ISCHR (archive_stat.st_mode)
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&& stat (dev_null, &dev_null_stat) == 0
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&& archive_stat.st_dev == dev_null_stat.st_dev
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&& archive_stat.st_ino == dev_null_stat.st_ino));
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}
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/* Manage to fully drain a pipe we might be reading, so to not break it on
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the producer after the EOF block. FIXME: one of these days, GNU tar
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might become clever enough to just stop working, once there is no more
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work to do, we might have to revise this area in such time. */
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void
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sys_drain_input_pipe ()
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{
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if (access_mode == ACCESS_READ
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&& ! _isrmt (archive)
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&& (S_ISFIFO (archive_stat.st_mode) || S_ISSOCK (archive_stat.st_mode)))
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while (rmtread (archive, record_start->buffer, record_size) > 0)
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continue;
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}
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void
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sys_wait_for_child (pid_t child_pid)
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{
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if (child_pid)
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{
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int wait_status;
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while (waitpid (child_pid, &wait_status, 0) == -1)
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if (errno != EINTR)
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{
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waitpid_error (use_compress_program_option);
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break;
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}
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if (WIFSIGNALED (wait_status))
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ERROR ((0, 0, _("Child died with signal %d"),
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WTERMSIG (wait_status)));
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else if (WEXITSTATUS (wait_status) != 0)
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ERROR ((0, 0, _("Child returned status %d"),
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WEXITSTATUS (wait_status)));
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}
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}
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void
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sys_spawn_shell ()
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{
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pid_t child;
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const char *shell = getenv ("SHELL");
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if (! shell)
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shell = "/bin/sh";
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child = xfork ();
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if (child == 0)
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{
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execlp (shell, "-sh", "-i", 0);
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exec_fatal (shell);
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}
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else
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{
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int wait_status;
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while (waitpid (child, &wait_status, 0) == -1)
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if (errno != EINTR)
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{
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waitpid_error (shell);
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break;
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}
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}
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}
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void
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sys_compare_uid_gid (struct stat *a, struct stat *b)
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{
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if (a->st_uid != b->st_uid)
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report_difference (_("Uid differs"));
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if (a->st_gid != b->st_gid)
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report_difference (_("Gid differs"));
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}
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void
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sys_compare_links (struct stat *link_data, struct stat *stat_data)
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{
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if (stat_data->st_dev != link_data->st_dev
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|| stat_data->st_ino != link_data->st_ino)
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{
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report_difference (_("Not linked to %s"),
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quote (current_stat_info.link_name));
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}
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}
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int
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sys_truncate (int fd)
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{
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off_t pos = lseek (fd, (off_t) 0, SEEK_CUR);
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return pos < 0 ? -1 : ftruncate (fd, pos);
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}
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void
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sys_reset_uid_gid ()
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{
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setuid (getuid ());
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setgid (getgid ());
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}
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/* Return nonzero if NAME is the name of a regular file, or if the file
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does not exist (so it would be created as a regular file). */
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static int
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is_regular_file (const char *name)
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{
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struct stat stbuf;
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if (stat (name, &stbuf) == 0)
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return S_ISREG (stbuf.st_mode);
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else
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return errno == ENOENT;
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}
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ssize_t
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sys_write_archive_buffer (void)
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{
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ssize_t status;
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ssize_t written = 0;
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while (0 <= (status = rmtwrite (archive, record_start->buffer + written,
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record_size - written)))
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{
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written += status;
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if (written == record_size
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|| _isrmt (archive)
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|| ! (S_ISFIFO (archive_stat.st_mode)
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|| S_ISSOCK (archive_stat.st_mode)))
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break;
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}
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return written ? written : status;
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}
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#define PREAD 0 /* read file descriptor from pipe() */
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#define PWRITE 1 /* write file descriptor from pipe() */
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/* Duplicate file descriptor FROM into becoming INTO.
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INTO is closed first and has to be the next available slot. */
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static void
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xdup2 (int from, int into)
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{
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if (from != into)
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{
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int status = close (into);
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if (status != 0 && errno != EBADF)
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{
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int e = errno;
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FATAL_ERROR ((0, e, _("Cannot close")));
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}
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status = dup (from);
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if (status != into)
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{
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if (status < 0)
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{
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int e = errno;
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FATAL_ERROR ((0, e, _("Cannot dup")));
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}
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abort ();
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}
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xclose (from);
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}
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}
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/* Set ARCHIVE for writing, then compressing an archive. */
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pid_t
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sys_child_open_for_compress (void)
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{
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int parent_pipe[2];
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int child_pipe[2];
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pid_t grandchild_pid;
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pid_t child_pid;
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int wait_status;
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xpipe (parent_pipe);
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child_pid = xfork ();
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if (child_pid > 0)
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{
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/* The parent tar is still here! Just clean up. */
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archive = parent_pipe[PWRITE];
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xclose (parent_pipe[PREAD]);
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return child_pid;
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}
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/* The new born child tar is here! */
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program_name = _("tar (child)");
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xdup2 (parent_pipe[PREAD], STDIN_FILENO);
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xclose (parent_pipe[PWRITE]);
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/* Check if we need a grandchild tar. This happens only if either:
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a) we are writing stdout: to force reblocking;
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b) the file is to be accessed by rmt: compressor doesn't know how;
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c) the file is not a plain file. */
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if (strcmp (archive_name_array[0], "-") != 0
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&& !_remdev (archive_name_array[0])
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&& is_regular_file (archive_name_array[0]))
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{
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if (backup_option)
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maybe_backup_file (archive_name_array[0], 1);
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/* We don't need a grandchild tar. Open the archive and launch the
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compressor. */
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archive = creat (archive_name_array[0], MODE_RW);
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if (archive < 0)
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{
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int saved_errno = errno;
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if (backup_option)
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undo_last_backup ();
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errno = saved_errno;
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open_fatal (archive_name_array[0]);
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}
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xdup2 (archive, STDOUT_FILENO);
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execlp (use_compress_program_option, use_compress_program_option,
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(char *) 0);
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exec_fatal (use_compress_program_option);
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}
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/* We do need a grandchild tar. */
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xpipe (child_pipe);
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grandchild_pid = xfork ();
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if (grandchild_pid == 0)
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{
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/* The newborn grandchild tar is here! Launch the compressor. */
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program_name = _("tar (grandchild)");
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xdup2 (child_pipe[PWRITE], STDOUT_FILENO);
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xclose (child_pipe[PREAD]);
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execlp (use_compress_program_option, use_compress_program_option,
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(char *) 0);
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exec_fatal (use_compress_program_option);
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}
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/* The child tar is still here! */
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/* Prepare for reblocking the data from the compressor into the archive. */
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xdup2 (child_pipe[PREAD], STDIN_FILENO);
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xclose (child_pipe[PWRITE]);
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if (strcmp (archive_name_array[0], "-") == 0)
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archive = STDOUT_FILENO;
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else
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{
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archive = rmtcreat (archive_name_array[0], MODE_RW, rsh_command_option);
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if (archive < 0)
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open_fatal (archive_name_array[0]);
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}
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/* Let's read out of the stdin pipe and write an archive. */
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while (1)
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{
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ssize_t status = 0;
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char *cursor;
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size_t length;
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/* Assemble a record. */
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for (length = 0, cursor = record_start->buffer;
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length < record_size;
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length += status, cursor += status)
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{
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size_t size = record_size - length;
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status = safe_read (STDIN_FILENO, cursor, size);
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if (status <= 0)
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break;
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}
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if (status < 0)
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read_fatal (use_compress_program_option);
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/* Copy the record. */
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if (status == 0)
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{
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/* We hit the end of the file. Write last record at
|
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full length, as the only role of the grandchild is
|
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doing proper reblocking. */
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if (length > 0)
|
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{
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memset (record_start->buffer + length, 0, record_size - length);
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status = sys_write_archive_buffer ();
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if (status != record_size)
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archive_write_error (status);
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}
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/* There is nothing else to read, break out. */
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break;
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}
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status = sys_write_archive_buffer ();
|
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if (status != record_size)
|
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archive_write_error (status);
|
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}
|
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|
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/* Propagate any failure of the grandchild back to the parent. */
|
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|
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while (waitpid (grandchild_pid, &wait_status, 0) == -1)
|
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if (errno != EINTR)
|
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{
|
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waitpid_error (use_compress_program_option);
|
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break;
|
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}
|
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|
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if (WIFSIGNALED (wait_status))
|
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{
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kill (child_pid, WTERMSIG (wait_status));
|
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exit_status = TAREXIT_FAILURE;
|
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}
|
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else if (WEXITSTATUS (wait_status) != 0)
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exit_status = WEXITSTATUS (wait_status);
|
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exit (exit_status);
|
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}
|
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|
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/* Set ARCHIVE for uncompressing, then reading an archive. */
|
||||
pid_t
|
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sys_child_open_for_uncompress (void)
|
||||
{
|
||||
int parent_pipe[2];
|
||||
int child_pipe[2];
|
||||
pid_t grandchild_pid;
|
||||
pid_t child_pid;
|
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int wait_status;
|
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|
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xpipe (parent_pipe);
|
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child_pid = xfork ();
|
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|
||||
if (child_pid > 0)
|
||||
{
|
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/* The parent tar is still here! Just clean up. */
|
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|
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read_full_records_option = 1;
|
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archive = parent_pipe[PREAD];
|
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xclose (parent_pipe[PWRITE]);
|
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return child_pid;
|
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}
|
||||
|
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/* The newborn child tar is here! */
|
||||
|
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program_name = _("tar (child)");
|
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|
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xdup2 (parent_pipe[PWRITE], STDOUT_FILENO);
|
||||
xclose (parent_pipe[PREAD]);
|
||||
|
||||
/* Check if we need a grandchild tar. This happens only if either:
|
||||
a) we're reading stdin: to force unblocking;
|
||||
b) the file is to be accessed by rmt: compressor doesn't know how;
|
||||
c) the file is not a plain file. */
|
||||
|
||||
if (strcmp (archive_name_array[0], "-") != 0
|
||||
&& !_remdev (archive_name_array[0])
|
||||
&& is_regular_file (archive_name_array[0]))
|
||||
{
|
||||
/* We don't need a grandchild tar. Open the archive and lauch the
|
||||
uncompressor. */
|
||||
|
||||
archive = open (archive_name_array[0], O_RDONLY | O_BINARY, MODE_RW);
|
||||
if (archive < 0)
|
||||
open_fatal (archive_name_array[0]);
|
||||
xdup2 (archive, STDIN_FILENO);
|
||||
execlp (use_compress_program_option, use_compress_program_option,
|
||||
"-d", (char *) 0);
|
||||
exec_fatal (use_compress_program_option);
|
||||
}
|
||||
|
||||
/* We do need a grandchild tar. */
|
||||
|
||||
xpipe (child_pipe);
|
||||
grandchild_pid = xfork ();
|
||||
|
||||
if (grandchild_pid == 0)
|
||||
{
|
||||
/* The newborn grandchild tar is here! Launch the uncompressor. */
|
||||
|
||||
program_name = _("tar (grandchild)");
|
||||
|
||||
xdup2 (child_pipe[PREAD], STDIN_FILENO);
|
||||
xclose (child_pipe[PWRITE]);
|
||||
execlp (use_compress_program_option, use_compress_program_option,
|
||||
"-d", (char *) 0);
|
||||
exec_fatal (use_compress_program_option);
|
||||
}
|
||||
|
||||
/* The child tar is still here! */
|
||||
|
||||
/* Prepare for unblocking the data from the archive into the
|
||||
uncompressor. */
|
||||
|
||||
xdup2 (child_pipe[PWRITE], STDOUT_FILENO);
|
||||
xclose (child_pipe[PREAD]);
|
||||
|
||||
if (strcmp (archive_name_array[0], "-") == 0)
|
||||
archive = STDIN_FILENO;
|
||||
else
|
||||
archive = rmtopen (archive_name_array[0], O_RDONLY | O_BINARY,
|
||||
MODE_RW, rsh_command_option);
|
||||
if (archive < 0)
|
||||
open_fatal (archive_name_array[0]);
|
||||
|
||||
/* Let's read the archive and pipe it into stdout. */
|
||||
|
||||
while (1)
|
||||
{
|
||||
char *cursor;
|
||||
size_t maximum;
|
||||
size_t count;
|
||||
ssize_t status;
|
||||
|
||||
clear_read_error_count ();
|
||||
|
||||
error_loop:
|
||||
status = rmtread (archive, record_start->buffer, record_size);
|
||||
if (status < 0)
|
||||
{
|
||||
archive_read_error ();
|
||||
goto error_loop;
|
||||
}
|
||||
if (status == 0)
|
||||
break;
|
||||
cursor = record_start->buffer;
|
||||
maximum = status;
|
||||
while (maximum)
|
||||
{
|
||||
count = maximum < BLOCKSIZE ? maximum : BLOCKSIZE;
|
||||
if (full_write (STDOUT_FILENO, cursor, count) != count)
|
||||
write_error (use_compress_program_option);
|
||||
cursor += count;
|
||||
maximum -= count;
|
||||
}
|
||||
}
|
||||
|
||||
xclose (STDOUT_FILENO);
|
||||
|
||||
/* Propagate any failure of the grandchild back to the parent. */
|
||||
|
||||
while (waitpid (grandchild_pid, &wait_status, 0) == -1)
|
||||
if (errno != EINTR)
|
||||
{
|
||||
waitpid_error (use_compress_program_option);
|
||||
break;
|
||||
}
|
||||
|
||||
if (WIFSIGNALED (wait_status))
|
||||
{
|
||||
kill (child_pid, WTERMSIG (wait_status));
|
||||
exit_status = TAREXIT_FAILURE;
|
||||
}
|
||||
else if (WEXITSTATUS (wait_status) != 0)
|
||||
exit_status = WEXITSTATUS (wait_status);
|
||||
|
||||
exit (exit_status);
|
||||
}
|
||||
|
||||
#endif /* not MSDOS */
|
||||
|
||||
Reference in New Issue
Block a user