diff options
Diffstat (limited to 'lib/savedir.c')
| -rw-r--r-- | lib/savedir.c | 206 |
1 files changed, 206 insertions, 0 deletions
diff --git a/lib/savedir.c b/lib/savedir.c new file mode 100644 index 0000000..5d7151e --- /dev/null +++ b/lib/savedir.c @@ -0,0 +1,206 @@ +/* savedir.c -- save the list of files in a directory in a string + + Copyright (C) 1990, 1997-2001, 2003-2006, 2009-2020 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 <https://www.gnu.org/licenses/>. */ + +/* Written by David MacKenzie <djm@gnu.ai.mit.edu>. */ + +#include <config.h> + +#include "savedir.h" + +#include <sys/types.h> + +#include <errno.h> + +#include "dirent--.h" +#ifndef _D_EXACT_NAMLEN +# define _D_EXACT_NAMLEN(dp) strlen ((dp)->d_name) +#endif + +#include <stddef.h> +#include <stdlib.h> +#include <string.h> + +#include "xalloc.h" + +typedef struct +{ + char *name; +#if D_INO_IN_DIRENT + ino_t ino; +#endif +} direntry_t; + +/* Compare the names of two directory entries */ + +static int +direntry_cmp_name (void const *a, void const *b) +{ + direntry_t const *dea = a; + direntry_t const *deb = b; + + return strcmp (dea->name, deb->name); +} + +#if D_INO_IN_DIRENT +/* Compare the inode numbers of two directory entries */ + +static int +direntry_cmp_inode (void const *a, void const *b) +{ + direntry_t const *dea = a; + direntry_t const *deb = b; + + return dea->ino < deb->ino ? -1 : dea->ino > deb->ino; +} +#endif + +typedef int (*comparison_function) (void const *, void const *); + +static comparison_function const comparison_function_table[] = + { + 0, + direntry_cmp_name +#if D_INO_IN_DIRENT + , direntry_cmp_inode +#endif + }; + +/* Return a freshly allocated string containing the file names + in directory DIRP, separated by '\0' characters; + the end is marked by two '\0' characters in a row. + Returned values are sorted according to OPTION. + Return NULL (setting errno) if DIRP cannot be read. + If DIRP is NULL, return NULL without affecting errno. */ + +char * +streamsavedir (DIR *dirp, enum savedir_option option) +{ + char *name_space = NULL; + size_t allocated = 0; + direntry_t *entries = NULL; + size_t entries_allocated = 0; + size_t entries_used = 0; + size_t used = 0; + int readdir_errno; + comparison_function cmp = comparison_function_table[option]; + + if (dirp == NULL) + return NULL; + + for (;;) + { + struct dirent const *dp; + char const *entry; + + errno = 0; + dp = readdir (dirp); + if (! dp) + break; + + /* Skip "", ".", and "..". "" is returned by at least one buggy + implementation: Solaris 2.4 readdir on NFS file systems. */ + entry = dp->d_name; + if (entry[entry[0] != '.' ? 0 : entry[1] != '.' ? 1 : 2] != '\0') + { + size_t entry_size = _D_EXACT_NAMLEN (dp) + 1; + if (cmp) + { + if (entries_allocated == entries_used) + { + size_t n = entries_allocated; + entries = x2nrealloc (entries, &n, sizeof *entries); + entries_allocated = n; + } + entries[entries_used].name = xstrdup (entry); +#if D_INO_IN_DIRENT + entries[entries_used].ino = dp->d_ino; +#endif + entries_used++; + } + else + { + if (allocated - used <= entry_size) + { + size_t n = used + entry_size; + if (n < used) + xalloc_die (); + name_space = x2nrealloc (name_space, &n, 1); + allocated = n; + } + memcpy (name_space + used, entry, entry_size); + } + used += entry_size; + } + } + + readdir_errno = errno; + if (readdir_errno != 0) + { + free (entries); + free (name_space); + errno = readdir_errno; + return NULL; + } + + if (cmp) + { + size_t i; + + if (entries_used) + qsort (entries, entries_used, sizeof *entries, cmp); + name_space = xmalloc (used + 1); + used = 0; + for (i = 0; i < entries_used; i++) + { + char *dest = name_space + used; + used += stpcpy (dest, entries[i].name) - dest + 1; + free (entries[i].name); + } + free (entries); + } + else if (used == allocated) + name_space = xrealloc (name_space, used + 1); + + name_space[used] = '\0'; + return name_space; +} + +/* Return a freshly allocated string containing the file names + in directory DIR, separated by '\0' characters; + the end is marked by two '\0' characters in a row. + Return NULL (setting errno) if DIR cannot be opened, read, or closed. */ + +char * +savedir (char const *dir, enum savedir_option option) +{ + DIR *dirp = opendir (dir); + if (! dirp) + return NULL; + else + { + char *name_space = streamsavedir (dirp, option); + if (closedir (dirp) != 0) + { + int closedir_errno = errno; + free (name_space); + errno = closedir_errno; + return NULL; + } + return name_space; + } +} |