/* Miscellaneous functions, not really specific to GNU tar. Copyright (C) 1988, 1992, 1994, 1995, 1996, 1997, 1999, 2000, 2001, 2003, 2004, 2005, 2006, 2007 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, 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, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */ #include #include #include "common.h" #include #include #include #include #include #if HAVE_STROPTS_H # include #endif #if HAVE_SYS_FILIO_H # include #endif /* Handling strings. */ /* Assign STRING to a copy of VALUE if not zero, or to zero. If STRING was nonzero, it is freed first. */ void assign_string (char **string, const char *value) { if (*string) free (*string); *string = value ? xstrdup (value) : 0; } /* Allocate a copy of the string quoted as in C, and returns that. If the string does not have to be quoted, it returns a null pointer. The allocated copy should normally be freed with free() after the caller is done with it. This is used in one context only: generating the directory file in incremental dumps. The quoted string is not intended for human consumption; it is intended only for unquote_string. The quoting is locale-independent, so that users needn't worry about locale when reading directory files. This means that we can't use quotearg, as quotearg is locale-dependent and is meant for human consumption. */ char * quote_copy_string (const char *string) { const char *source = string; char *destination = 0; char *buffer = 0; int copying = 0; while (*source) { int character = *source++; switch (character) { case '\n': case '\\': if (!copying) { size_t length = (source - string) - 1; copying = 1; buffer = xmalloc (length + 2 + 2 * strlen (source) + 1); memcpy (buffer, string, length); destination = buffer + length; } *destination++ = '\\'; *destination++ = character == '\\' ? '\\' : 'n'; break; default: if (copying) *destination++ = character; break; } } if (copying) { *destination = '\0'; return buffer; } return 0; } /* Takes a quoted C string (like those produced by quote_copy_string) and turns it back into the un-quoted original. This is done in place. Returns 0 only if the string was not properly quoted, but completes the unquoting anyway. This is used for reading the saved directory file in incremental dumps. It is used for decoding old `N' records (demangling names). But also, it is used for decoding file arguments, would they come from the shell or a -T file, and for decoding the --exclude argument. */ int unquote_string (char *string) { int result = 1; char *source = string; char *destination = string; /* Escape sequences other than \\ and \n are no longer generated by quote_copy_string, but accept them for backwards compatibility, and also because unquote_string is used for purposes other than parsing the output of quote_copy_string. */ while (*source) if (*source == '\\') switch (*++source) { case '\\': *destination++ = '\\'; source++; break; case 'a': *destination++ = '\a'; source++; break; case 'b': *destination++ = '\b'; source++; break; case 'f': *destination++ = '\f'; source++; break; case 'n': *destination++ = '\n'; source++; break; case 'r': *destination++ = '\r'; source++; break; case 't': *destination++ = '\t'; source++; break; case 'v': *destination++ = '\v'; source++; break; case '?': *destination++ = 0177; source++; break; case '0': case '1': case '2': case '3': case '4': case '5': case '6': case '7': { int value = *source++ - '0'; if (*source < '0' || *source > '7') { *destination++ = value; break; } value = value * 8 + *source++ - '0'; if (*source < '0' || *source > '7') { *destination++ = value; break; } value = value * 8 + *source++ - '0'; *destination++ = value; break; } default: result = 0; *destination++ = '\\'; if (*source) *destination++ = *source++; break; } else if (source != destination) *destination++ = *source++; else source++, destination++; if (source != destination) *destination = '\0'; return result; } /* Handling numbers. */ /* Output fraction and trailing digits appropriate for a nanoseconds count equal to NS, but don't output unnecessary '.' or trailing zeros. */ void code_ns_fraction (int ns, char *p) { if (ns == 0) *p = '\0'; else { int i = 9; *p++ = '.'; while (ns % 10 == 0) { ns /= 10; i--; } p[i] = '\0'; for (;;) { p[--i] = '0' + ns % 10; if (i == 0) break; ns /= 10; } } } char const * code_timespec (struct timespec t, char sbuf[TIMESPEC_STRSIZE_BOUND]) { time_t s = t.tv_sec; int ns = t.tv_nsec; char *np; bool negative = s < 0; if (negative && ns != 0) { s++; ns = BILLION - ns; } np = umaxtostr (negative ? - (uintmax_t) s : (uintmax_t) s, sbuf + 1); if (negative) *--np = '-'; code_ns_fraction (ns, sbuf + UINTMAX_STRSIZE_BOUND); return np; } /* File handling. */ /* Saved names in case backup needs to be undone. */ static char *before_backup_name; static char *after_backup_name; /* Return 1 if FILE_NAME is obviously "." or "/". */ static bool must_be_dot_or_slash (char const *file_name) { file_name += FILE_SYSTEM_PREFIX_LEN (file_name); if (ISSLASH (file_name[0])) { for (;;) if (ISSLASH (file_name[1])) file_name++; else if (file_name[1] == '.' && ISSLASH (file_name[2 + (file_name[2] == '.')])) file_name += 2 + (file_name[2] == '.'); else return ! file_name[1]; } else { while (file_name[0] == '.' && ISSLASH (file_name[1])) { file_name += 2; while (ISSLASH (*file_name)) file_name++; } return ! file_name[0] || (file_name[0] == '.' && ! file_name[1]); } } /* Some implementations of rmdir let you remove '.' or '/'. Report an error with errno set to zero for obvious cases of this; otherwise call rmdir. */ static int safer_rmdir (const char *file_name) { if (must_be_dot_or_slash (file_name)) { errno = 0; return -1; } return rmdir (file_name); } /* Remove FILE_NAME, returning 1 on success. If FILE_NAME is a directory, then if OPTION is RECURSIVE_REMOVE_OPTION is set remove FILE_NAME recursively; otherwise, remove it only if it is empty. If FILE_NAME is a directory that cannot be removed (e.g., because it is nonempty) and if OPTION is WANT_DIRECTORY_REMOVE_OPTION, then return -1. Return 0 on error, with errno set; if FILE_NAME is obviously the working directory return zero with errno set to zero. */ int remove_any_file (const char *file_name, enum remove_option option) { /* Try unlink first if we cannot unlink directories, as this saves us a system call in the common case where we're removing a non-directory. */ bool try_unlink_first = cannot_unlink_dir (); if (try_unlink_first) { if (unlink (file_name) == 0) return 1; /* POSIX 1003.1-2001 requires EPERM when attempting to unlink a directory without appropriate privileges, but many Linux kernels return the more-sensible EISDIR. */ if (errno != EPERM && errno != EISDIR) return 0; } if (safer_rmdir (file_name) == 0) return 1; switch (errno) { case ENOTDIR: return !try_unlink_first && unlink (file_name) == 0; case 0: case EEXIST: #if defined ENOTEMPTY && ENOTEMPTY != EEXIST case ENOTEMPTY: #endif switch (option) { case ORDINARY_REMOVE_OPTION: break; case WANT_DIRECTORY_REMOVE_OPTION: return -1; case RECURSIVE_REMOVE_OPTION: { char *directory = savedir (file_name); char const *entry; size_t entrylen; if (! directory) return 0; for (entry = directory; (entrylen = strlen (entry)) != 0; entry += entrylen + 1) { char *file_name_buffer = new_name (file_name, entry); int r = remove_any_file (file_name_buffer, RECURSIVE_REMOVE_OPTION); int e = errno; free (file_name_buffer); if (! r) { free (directory); errno = e; return 0; } } free (directory); return safer_rmdir (file_name) == 0; } } break; } return 0; } /* Check if FILE_NAME already exists and make a backup of it right now. Return success (nonzero) only if the backup is either unneeded, or successful. For now, directories are considered to never need backup. If THIS_IS_THE_ARCHIVE is nonzero, this is the archive and so, we do not have to backup block or character devices, nor remote entities. */ bool maybe_backup_file (const char *file_name, bool this_is_the_archive) { struct stat file_stat; /* Check if we really need to backup the file. */ if (this_is_the_archive && _remdev (file_name)) return true; if (stat (file_name, &file_stat)) { if (errno == ENOENT) return true; stat_error (file_name); return false; } if (S_ISDIR (file_stat.st_mode)) return true; if (this_is_the_archive && (S_ISBLK (file_stat.st_mode) || S_ISCHR (file_stat.st_mode))) return true; assign_string (&before_backup_name, file_name); /* A run situation may exist between Emacs or other GNU programs trying to make a backup for the same file simultaneously. If theoretically possible, real problems are unlikely. Doing any better would require a convention, GNU-wide, for all programs doing backups. */ assign_string (&after_backup_name, 0); after_backup_name = find_backup_file_name (file_name, backup_type); if (! after_backup_name) xalloc_die (); if (rename (before_backup_name, after_backup_name) == 0) { if (verbose_option) fprintf (stdlis, _("Renaming %s to %s\n"), quote_n (0, before_backup_name), quote_n (1, after_backup_name)); return true; } else { /* The backup operation failed. */ int e = errno; ERROR ((0, e, _("%s: Cannot rename to %s"), quotearg_colon (before_backup_name), quote_n (1, after_backup_name))); assign_string (&after_backup_name, 0); return false; } } /* Try to restore the recently backed up file to its original name. This is usually only needed after a failed extraction. */ void undo_last_backup (void) { if (after_backup_name) { if (rename (after_backup_name, before_backup_name) != 0) { int e = errno; ERROR ((0, e, _("%s: Cannot rename to %s"), quotearg_colon (after_backup_name), quote_n (1, before_backup_name))); } if (verbose_option) fprintf (stdlis, _("Renaming %s back to %s\n"), quote_n (0, after_backup_name), quote_n (1, before_backup_name)); assign_string (&after_backup_name, 0); } } /* Depending on DEREF, apply either stat or lstat to (NAME, BUF). */ int deref_stat (bool deref, char const *name, struct stat *buf) { return deref ? stat (name, buf) : lstat (name, buf); } /* Set FD's (i.e., FILE's) access time to TIMESPEC[0]. If that's not possible to do by itself, set its access and data modification times to TIMESPEC[0] and TIMESPEC[1], respectively. */ int set_file_atime (int fd, char const *file, struct timespec const timespec[2]) { #ifdef _FIOSATIME if (0 <= fd) { struct timeval timeval; timeval.tv_sec = timespec[0].tv_sec; timeval.tv_usec = timespec[0].tv_nsec / 1000; if (ioctl (fd, _FIOSATIME, &timeval) == 0) return 0; } #endif return gl_futimens (fd, file, timespec); } /* A description of a working directory. */ struct wd { char const *name; int saved; struct saved_cwd saved_cwd; }; /* A vector of chdir targets. wd[0] is the initial working directory. */ static struct wd *wd; /* The number of working directories in the vector. */ static size_t wds; /* The allocated size of the vector. */ static size_t wd_alloc; /* DIR is the operand of a -C option; add it to vector of chdir targets, and return the index of its location. */ int chdir_arg (char const *dir) { if (wds == wd_alloc) { if (wd_alloc == 0) { wd_alloc = 2; wd = xmalloc (sizeof *wd * wd_alloc); } else wd = x2nrealloc (wd, &wd_alloc, sizeof *wd); if (! wds) { wd[wds].name = "."; wd[wds].saved = 0; wds++; } } /* Optimize the common special case of the working directory, or the working directory as a prefix. */ if (dir[0]) { while (dir[0] == '.' && ISSLASH (dir[1])) for (dir += 2; ISSLASH (*dir); dir++) continue; if (! dir[dir[0] == '.']) return wds - 1; } wd[wds].name = dir; wd[wds].saved = 0; return wds++; } /* Change to directory I. If I is 0, change to the initial working directory; otherwise, I must be a value returned by chdir_arg. */ void chdir_do (int i) { static int previous; if (previous != i) { struct wd *prev = &wd[previous]; struct wd *curr = &wd[i]; if (! prev->saved) { int err = 0; prev->saved = 1; if (save_cwd (&prev->saved_cwd) != 0) err = errno; else if (0 <= prev->saved_cwd.desc) { /* Make sure we still have at least one descriptor available. */ int fd1 = prev->saved_cwd.desc; int fd2 = dup (fd1); if (0 <= fd2) close (fd2); else if (errno == EMFILE) { /* Force restore_cwd to use chdir_long. */ close (fd1); prev->saved_cwd.desc = -1; prev->saved_cwd.name = xgetcwd (); } else err = errno; } if (err) FATAL_ERROR ((0, err, _("Cannot save working directory"))); } if (curr->saved) { if (restore_cwd (&curr->saved_cwd)) FATAL_ERROR ((0, 0, _("Cannot change working directory"))); } else { if (i && ! ISSLASH (curr->name[0])) chdir_do (i - 1); if (chdir (curr->name) != 0) chdir_fatal (curr->name); } previous = i; } } void close_diag (char const *name) { if (ignore_failed_read_option) close_warn (name); else close_error (name); } void open_diag (char const *name) { if (ignore_failed_read_option) open_warn (name); else open_error (name); } void read_diag_details (char const *name, off_t offset, size_t size) { if (ignore_failed_read_option) read_warn_details (name, offset, size); else read_error_details (name, offset, size); } void readlink_diag (char const *name) { if (ignore_failed_read_option) readlink_warn (name); else readlink_error (name); } void savedir_diag (char const *name) { if (ignore_failed_read_option) savedir_warn (name); else savedir_error (name); } void seek_diag_details (char const *name, off_t offset) { if (ignore_failed_read_option) seek_warn_details (name, offset); else seek_error_details (name, offset); } void stat_diag (char const *name) { if (ignore_failed_read_option) stat_warn (name); else stat_error (name); } void write_fatal_details (char const *name, ssize_t status, size_t size) { write_error_details (name, status, size); fatal_exit (); } /* Fork, aborting if unsuccessful. */ pid_t xfork (void) { pid_t p = fork (); if (p == (pid_t) -1) call_arg_fatal ("fork", _("child process")); return p; } /* Create a pipe, aborting if unsuccessful. */ void xpipe (int fd[2]) { if (pipe (fd) < 0) call_arg_fatal ("pipe", _("interprocess channel")); } /* Return PTR, aligned upward to the next multiple of ALIGNMENT. ALIGNMENT must be nonzero. The caller must arrange for ((char *) PTR) through ((char *) PTR + ALIGNMENT - 1) to be addressable locations. */ static inline void * ptr_align (void *ptr, size_t alignment) { char *p0 = ptr; char *p1 = p0 + alignment - 1; return p1 - (size_t) p1 % alignment; } /* Return the address of a page-aligned buffer of at least SIZE bytes. The caller should free *PTR when done with the buffer. */ void * page_aligned_alloc (void **ptr, size_t size) { size_t alignment = getpagesize (); size_t size1 = size + alignment; if (size1 < size) xalloc_die (); *ptr = xmalloc (size1); return ptr_align (*ptr, alignment); }