Merge everything into one filesingle-file

36 files changed, 14266 insertions, 14389 deletions

diff --git a/Makefile b/Makefile
index 6195eca..e8d62ca 100644
--- a/Makefile
+++ b/Makefile
@@ -68,24 +68,7 @@ default: bfs
 
 all: bfs tests/mksock
 
-bfs: \
-    bftw.o \
-    color.o \
-    diag.o \
-    dstring.o \
-    eval.o \
-    exec.o \
-    fsade.o \
-    main.o \
-    mtab.o \
-    opt.o \
-    parse.o \
-    printf.o \
-    spawn.o \
-    stat.o \
-    trie.o \
-    typo.o \
-    util.o
+bfs: bfs.o
 	$(CC) $(ALL_LDFLAGS) $^ $(ALL_LDLIBS) -o $@
 
 release: CFLAGS := -g $(WFLAGS) -O3 -flto -DNDEBUG
diff --git a/bfs.c b/bfs.c
new file mode 100644
index 0000000..ce7cbb0
--- /dev/null
+++ b/bfs.c
@@ -0,0 +1,14265 @@
+/****************************************************************************
+ * bfs                                                                      *
+ * Copyright (C) 2016-2019 Tavian Barnes <tavianator@tavianator.com>        *
+ *                                                                          *
+ * Permission to use, copy, modify, and/or distribute this software for any *
+ * purpose with or without fee is hereby granted.                           *
+ *                                                                          *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES *
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF         *
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR  *
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES   *
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN    *
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF  *
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.           *
+ ****************************************************************************/
+
+/**
+ * Assorted utilities that don't belong anywhere else.
+ */
+
+#ifndef BFS_UTIL_H
+#define BFS_UTIL_H
+
+#include <dirent.h>
+#include <fcntl.h>
+#include <fnmatch.h>
+#include <regex.h>
+#include <stdbool.h>
+#include <sys/types.h>
+#include <time.h>
+
+// Some portability concerns
+
+#ifdef __has_feature
+#	define BFS_HAS_FEATURE(feature, fallback) __has_feature(feature)
+#else
+#	define BFS_HAS_FEATURE(feature, fallback) fallback
+#endif
+
+#ifdef __has_include
+#	define BFS_HAS_INCLUDE(header, fallback) __has_include(header)
+#else
+#	define BFS_HAS_INCLUDE(header, fallback) fallback
+#endif
+
+#ifndef BFS_HAS_MNTENT
+#	define BFS_HAS_MNTENT BFS_HAS_INCLUDE(<mntent.h>, __GLIBC__)
+#endif
+
+#ifndef BFS_HAS_SYS_ACL
+#	define BFS_HAS_SYS_ACL BFS_HAS_INCLUDE(<sys/acl.h>, true)
+#endif
+
+#ifndef BFS_HAS_SYS_CAPABILITY
+#	define BFS_HAS_SYS_CAPABILITY BFS_HAS_INCLUDE(<sys/capability.h>, __linux__)
+#endif
+
+#ifndef BFS_HAS_SYS_MKDEV
+#	define BFS_HAS_SYS_MKDEV BFS_HAS_INCLUDE(<sys/mkdev.h>, false)
+#endif
+
+#ifndef BFS_HAS_SYS_PARAM
+#	define BFS_HAS_SYS_PARAM BFS_HAS_INCLUDE(<sys/param.h>, true)
+#endif
+
+#ifndef BFS_HAS_SYS_SYSMACROS
+#	define BFS_HAS_SYS_SYSMACROS BFS_HAS_INCLUDE(<sys/sysmacros.h>, __GLIBC__)
+#endif
+
+#ifndef BFS_HAS_SYS_XATTR
+#	define BFS_HAS_SYS_XATTR BFS_HAS_INCLUDE(<sys/xattr.h>, __linux__)
+#endif
+
+#if !defined(FNM_CASEFOLD) && defined(FNM_IGNORECASE)
+#	define FNM_CASEFOLD FNM_IGNORECASE
+#endif
+
+#ifndef O_DIRECTORY
+#	define O_DIRECTORY 0
+#endif
+
+/**
+ * Adds compiler warnings for bad printf()-style function calls, if supported.
+ */
+#if __GNUC__
+#	define BFS_FORMATTER(fmt, args) __attribute__((format(printf, fmt, args)))
+#else
+#	define BFS_FORMATTER(fmt, args)
+#endif
+
+/**
+ * readdir() wrapper that makes error handling cleaner.
+ */
+int xreaddir(DIR *dir, struct dirent **de);
+
+/**
+ * readlinkat() wrapper that dynamically allocates the result.
+ *
+ * @param fd
+ *         The base directory descriptor.
+ * @param path
+ *         The path to the link, relative to fd.
+ * @param size
+ *         An estimate for the size of the link name (pass 0 if unknown).
+ * @return The target of the link, allocated with malloc(), or NULL on failure.
+ */
+char *xreadlinkat(int fd, const char *path, size_t size);
+
+/**
+ * Check if a file descriptor is open.
+ */
+bool isopen(int fd);
+
+/**
+ * Open a file and redirect it to a particular descriptor.
+ *
+ * @param fd
+ *         The file descriptor to redirect.
+ * @param path
+ *         The path to open.
+ * @param flags
+ *         The flags passed to open().
+ * @param mode
+ *         The mode passed to open() (optional).
+ * @return fd on success, -1 on failure.
+ */
+int redirect(int fd, const char *path, int flags, ...);
+
+/**
+ * Like dup(), but set the FD_CLOEXEC flag.
+ *
+ * @param fd
+ *         The file descriptor to duplicate.
+ * @return A duplicated file descriptor, or -1 on failure.
+ */
+int dup_cloexec(int fd);
+
+/**
+ * Like pipe(), but set the FD_CLOEXEC flag.
+ *
+ * @param pipefd
+ *         The array to hold the two file descriptors.
+ * @return 0 on success, -1 on failure.
+ */
+int pipe_cloexec(int pipefd[2]);
+
+/**
+ * Dynamically allocate a regex error message.
+ *
+ * @param err
+ *         The error code to stringify.
+ * @param regex
+ *         The (partially) compiled regex.
+ * @return A human-readable description of the error, allocated with malloc().
+ */
+char *xregerror(int err, const regex_t *regex);
+
+/**
+ * localtime_r() wrapper that calls tzset() first.
+ *
+ * @param timep
+ *         The time_t to convert.
+ * @param result
+ *         Buffer to hold the result.
+ * @return 0 on success, -1 on failure.
+ */
+int xlocaltime(const time_t *timep, struct tm *result);
+
+/**
+ * Format a mode like ls -l (e.g. -rw-r--r--).
+ *
+ * @param mode
+ *         The mode to format.
+ * @param str
+ *         The string to hold the formatted mode.
+ */
+void format_mode(mode_t mode, char str[11]);
+
+/**
+ * basename() variant that doesn't modify the input.
+ *
+ * @param path
+ *         The path in question.
+ * @return A pointer into path at the base name offset.
+ */
+const char *xbasename(const char *path);
+
+/**
+ * Wrapper for faccessat() that handles some portability issues.
+ */
+int xfaccessat(int fd, const char *path, int amode);
+
+/**
+ * Return whether an error code is due to a path not existing.
+ */
+bool is_nonexistence_error(int error);
+
+/**
+ * Process a yes/no prompt.
+ *
+ * @return 1 for yes, 0 for no, and -1 for unknown.
+ */
+int ynprompt(void);
+
+/**
+ * Portable version of makedev().
+ */
+dev_t bfs_makedev(int ma, int mi);
+
+/**
+ * Portable version of major().
+ */
+int bfs_major(dev_t dev);
+
+/**
+ * Portable version of minor().
+ */
+int bfs_minor(dev_t dev);
+
+#endif // BFS_UTIL_H
+/****************************************************************************
+ * bfs                                                                      *
+ * Copyright (C) 2018-2019 Tavian Barnes <tavianator@tavianator.com>        *
+ *                                                                          *
+ * Permission to use, copy, modify, and/or distribute this software for any *
+ * purpose with or without fee is hereby granted.                           *
+ *                                                                          *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES *
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF         *
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR  *
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES   *
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN    *
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF  *
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.           *
+ ****************************************************************************/
+
+/**
+ * A facade over the stat() API that unifies some details that diverge between
+ * implementations, like the names of the timespec fields and the presence of
+ * file "birth" times.  On new enough Linux kernels, the facade is backed by
+ * statx() instead, and so it exposes a similar interface with a mask for which
+ * fields were successfully returned.
+ */
+
+#ifndef BFS_STAT_H
+#define BFS_STAT_H
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <time.h>
+
+#if BFS_HAS_SYS_PARAM
+#	include <sys/param.h>
+#endif
+
+/**
+ * bfs_stat field bitmask.
+ */
+enum bfs_stat_field {
+	BFS_STAT_DEV    = 1 << 0,
+	BFS_STAT_INO    = 1 << 1,
+	BFS_STAT_TYPE   = 1 << 2,
+	BFS_STAT_MODE   = 1 << 3,
+	BFS_STAT_NLINK  = 1 << 4,
+	BFS_STAT_GID    = 1 << 5,
+	BFS_STAT_UID    = 1 << 6,
+	BFS_STAT_SIZE   = 1 << 7,
+	BFS_STAT_BLOCKS = 1 << 8,
+	BFS_STAT_RDEV   = 1 << 9,
+	BFS_STAT_ATIME  = 1 << 10,
+	BFS_STAT_BTIME  = 1 << 11,
+	BFS_STAT_CTIME  = 1 << 12,
+	BFS_STAT_MTIME  = 1 << 13,
+};
+
+/**
+ * Get the human-readable name of a bfs_stat field.
+ */
+const char *bfs_stat_field_name(enum bfs_stat_field field);
+
+/**
+ * bfs_stat() flags.
+ */
+enum bfs_stat_flag {
+	/** Follow symlinks (the default). */
+	BFS_STAT_FOLLOW = 0,
+	/** Never follow symlinks. */
+	BFS_STAT_NOFOLLOW = 1 << 0,
+	/** Try to follow symlinks, but fall back to the link itself if broken. */
+	BFS_STAT_TRYFOLLOW = 1 << 1,
+};
+
+#ifdef DEV_BSIZE
+#	define BFS_STAT_BLKSIZE DEV_BSIZE
+#elif defined(S_BLKSIZE)
+#	define BFS_STAT_BLKSIZE S_BLKSIZE
+#else
+#	define BFS_STAT_BLKSIZE 512
+#endif
+
+/**
+ * Facade over struct stat.
+ */
+struct bfs_stat {
+	/** Bitmask indicating filled fields. */
+	enum bfs_stat_field mask;
+
+	/** Device ID containing the file. */
+	dev_t dev;
+	/** Inode number. */
+	ino_t ino;
+	/** File type and access mode. */
+	mode_t mode;
+	/** Number of hard links. */
+	nlink_t nlink;
+	/** Owner group ID. */
+	gid_t gid;
+	/** Owner user ID. */
+	uid_t uid;
+	/** File size in bytes. */
+	off_t size;
+	/** Number of disk blocks allocated (of size BFS_STAT_BLKSIZE). */
+	blkcnt_t blocks;
+	/** The device ID represented by this file. */
+	dev_t rdev;
+
+	/** Access time. */
+	struct timespec atime;
+	/** Birth/creation time. */
+	struct timespec btime;
+	/** Status change time. */
+	struct timespec ctime;
+	/** Modification time. */
+	struct timespec mtime;
+};
+
+/**
+ * Facade over fstatat().
+ *
+ * @param at_fd
+ *         The base file descriptor for the lookup.
+ * @param at_path
+ *         The path to stat, relative to at_fd.  Pass NULL to fstat() at_fd
+ *         itself.
+ * @param flags
+ *         Flags that affect the lookup.
+ * @param[out] buf
+ *         A place to store the stat buffer, if successful.
+ * @return
+ *         0 on success, -1 on error.
+ */
+int bfs_stat(int at_fd, const char *at_path, enum bfs_stat_flag flags, struct bfs_stat *buf);
+
+/**
+ * Get a particular time field from a bfs_stat() buffer.
+ */
+const struct timespec *bfs_stat_time(const struct bfs_stat *buf, enum bfs_stat_field field);
+
+/**
+ * A unique ID for a file.
+ */
+typedef unsigned char bfs_file_id[sizeof(dev_t) + sizeof(ino_t)];
+
+/**
+ * Compute a unique ID for a file.
+ */
+void bfs_stat_id(const struct bfs_stat *buf, bfs_file_id *id);
+
+#endif // BFS_STAT_H
+/****************************************************************************
+ * bfs                                                                      *
+ * Copyright (C) 2015-2018 Tavian Barnes <tavianator@tavianator.com>        *
+ *                                                                          *
+ * Permission to use, copy, modify, and/or distribute this software for any *
+ * purpose with or without fee is hereby granted.                           *
+ *                                                                          *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES *
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF         *
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR  *
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES   *
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN    *
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF  *
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.           *
+ ****************************************************************************/
+
+/**
+ * Utilities for colored output on ANSI terminals.
+ */
+
+#ifndef BFS_COLOR_H
+#define BFS_COLOR_H
+
+#include <stdarg.h>
+#include <stdbool.h>
+#include <stdio.h>
+
+/**
+ * A lookup table for colors.
+ */
+struct colors;
+
+/**
+ * Parse a color table.
+ *
+ * @param ls_colors
+ *         A color table in the LS_COLORS environment variable format.
+ * @return The parsed color table.
+ */
+struct colors *parse_colors(const char *ls_colors);
+
+/**
+ * Free a color table.
+ *
+ * @param colors
+ *         The color table to free.
+ */
+void free_colors(struct colors *colors);
+
+/**
+ * A file/stream with associated colors.
+ */
+typedef struct CFILE {
+	/** The underlying file/stream. */
+	FILE *file;
+	/** The color table to use, if any. */
+	const struct colors *colors;
+	/** Whether to close the underlying stream. */
+	bool close;
+} CFILE;
+
+/**
+ * Open a file for colored output.
+ *
+ * @param path
+ *         The path to the file to open.
+ * @param colors
+ *         The color table to use if file is a TTY.
+ * @return A colored file stream.
+ */
+CFILE *cfopen(const char *path, const struct colors *colors);
+
+/**
+ * Make a colored copy of an open file.
+ *
+ * @param file
+ *         The underlying file.
+ * @param colors
+ *         The color table to use if file is a TTY.
+ * @return A colored wrapper around file.
+ */
+CFILE *cfdup(FILE *file, const struct colors *colors);
+
+/**
+ * Close a colored file.
+ *
+ * @param cfile
+ *         The colored file to close.
+ * @return 0 on success, -1 on failure.
+ */
+int cfclose(CFILE *cfile);
+
+/**
+ * Colored, formatted output.
+ *
+ * @param cfile
+ *         The colored stream to print to.
+ * @param format
+ *         A printf()-style format string, supporting these format specifiers:
+ *
+ *         %c: A single character
+ *         %d: An integer
+ *         %g: A double
+ *         %s: A string
+ *         %zu: A size_t
+ *         %m: strerror(errno)
+ *         %pP: A colored file path, from a const struct BFTW * argument
+ *         %pL: A colored link target, from a const struct BFTW * argument
+ *         %%: A literal '%'
+ *         ${cc}: Change the color to 'cc'
+ *         $$: A literal '$'
+ * @return 0 on success, -1 on failure.
+ */
+BFS_FORMATTER(2, 3)
+int cfprintf(CFILE *cfile, const char *format, ...);
+
+/**
+ * cfprintf() variant that takes a va_list.
+ */
+int cvfprintf(CFILE *cfile, const char *format, va_list args);
+
+#endif // BFS_COLOR_H
+/****************************************************************************
+ * bfs                                                                      *
+ * Copyright (C) 2019 Tavian Barnes <tavianator@tavianator.com>             *
+ *                                                                          *
+ * Permission to use, copy, modify, and/or distribute this software for any *
+ * purpose with or without fee is hereby granted.                           *
+ *                                                                          *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES *
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF         *
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR  *
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES   *
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN    *
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF  *
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.           *
+ ****************************************************************************/
+
+#ifndef BFS_TRIE_H
+#define BFS_TRIE_H
+
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdint.h>
+
+/**
+ * A trie that holds a set of fixed- or variable-length strings.
+ */
+struct trie {
+	uintptr_t root;
+};
+
+/**
+ * A leaf of a trie.
+ */
+struct trie_leaf {
+	/**
+	 * An arbitrary value associated with this leaf.
+	 */
+	void *value;
+
+	/**
+	 * The length of the key in bytes.
+	 */
+	size_t length;
+
+	/**
+	 * The key itself, stored inline.
+	 */
+	char key[];
+};
+
+/**
+ * Initialize an empty trie.
+ */
+void trie_init(struct trie *trie);
+
+/**
+ * Get the first (lexicographically earliest) leaf in the trie.
+ *
+ * @param trie
+ *         The trie to search.
+ * @return
+ *         The first leaf, or NULL if the trie is empty.
+ */
+struct trie_leaf *trie_first_leaf(const struct trie *trie);
+
+/**
+ * Find the leaf for a string key.
+ *
+ * @param trie
+ *         The trie to search.
+ * @param key
+ *         The key to look up.
+ * @return
+ *         The found leaf, or NULL if the key is not present.
+ */
+struct trie_leaf *trie_find_str(const struct trie *trie, const char *key);
+
+/**
+ * Find the leaf for a fixed-size key.
+ *
+ * @param trie
+ *         The trie to search.
+ * @param key
+ *         The key to look up.
+ * @param length
+ *         The length of the key in bytes.
+ * @return
+ *         The found leaf, or NULL if the key is not present.
+ */
+struct trie_leaf *trie_find_mem(const struct trie *trie, const void *key, size_t length);
+
+/**
+ * Find the shortest leaf that starts with a given key.
+ *
+ * @param trie
+ *         The trie to search.
+ * @param key
+ *         The key to look up.
+ * @return
+ *         A leaf that starts with the given key, or NULL.
+ */
+struct trie_leaf *trie_find_postfix(const struct trie *trie, const char *key);
+
+/**
+ * Find the leaf that is the longest prefix of the given key.
+ *
+ * @param trie
+ *         The trie to search.
+ * @param key
+ *         The key to look up.
+ * @return
+ *         The longest prefix match for the given key, or NULL.
+ */
+struct trie_leaf *trie_find_prefix(const struct trie *trie, const char *key);
+
+/**
+ * Insert a string key into the trie.
+ *
+ * @param trie
+ *         The trie to modify.
+ * @param key
+ *         The key to insert.
+ * @return
+ *         The inserted leaf, or NULL on failure.
+ */
+struct trie_leaf *trie_insert_str(struct trie *trie, const char *key);
+
+/**
+ * Insert a fixed-size key into the trie.
+ *
+ * @param trie
+ *         The trie to modify.
+ * @param key
+ *         The key to insert.
+ * @param length
+ *         The length of the key in bytes.
+ * @return
+ *         The inserted leaf, or NULL on failure.
+ */
+struct trie_leaf *trie_insert_mem(struct trie *trie, const void *key, size_t length);
+
+/**
+ * Remove a leaf from a trie.
+ *
+ * @param trie
+ *         The trie to modify.
+ * @param leaf
+ *         The leaf to remove.
+ */
+void trie_remove(struct trie *trie, struct trie_leaf *leaf);
+
+/**
+ * Destroy a trie and its contents.
+ */
+void trie_destroy(struct trie *trie);
+
+#endif // BFS_TRIE_H
+/****************************************************************************
+ * bfs                                                                      *
+ * Copyright (C) 2015-2018 Tavian Barnes <tavianator@tavianator.com>        *
+ *                                                                          *
+ * Permission to use, copy, modify, and/or distribute this software for any *
+ * purpose with or without fee is hereby granted.                           *
+ *                                                                          *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES *
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF         *
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR  *
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES   *
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN    *
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF  *
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.           *
+ ****************************************************************************/
+
+/**
+ * The expression tree representation.
+ */
+
+#ifndef BFS_EXPR_H
+#define BFS_EXPR_H
+
+#include <regex.h>
+#include <stdbool.h>
+#include <stddef.h>
+#include <sys/types.h>
+#include <time.h>
+
+/**
+ * A command line expression.
+ */
+struct expr;
+
+/**
+ * Ephemeral state for evaluating an expression.
+ */
+struct eval_state;
+
+/**
+ * Expression evaluation function.
+ *
+ * @param expr
+ *         The current expression.
+ * @param state
+ *         The current evaluation state.
+ * @return
+ *         The result of the test.
+ */
+typedef bool eval_fn(const struct expr *expr, struct eval_state *state);
+
+/**
+ * Possible types of numeric comparison.
+ */
+enum cmp_flag {
+	/** Exactly n. */
+	CMP_EXACT,
+	/** Less than n. */
+	CMP_LESS,
+	/** Greater than n. */
+	CMP_GREATER,
+};
+
+/**
+ * Possible types of mode comparison.
+ */
+enum mode_cmp {
+	/** Mode is an exact match (MODE). */
+	MODE_EXACT,
+	/** Mode has all these bits (-MODE). */
+	MODE_ALL,
+	/** Mode has any of these bits (/MODE). */
+	MODE_ANY,
+};
+
+/**
+ * Possible time units.
+ */
+enum time_unit {
+	/** Minutes. */
+	MINUTES,
+	/** Days. */
+	DAYS,
+};
+
+/**
+ * Possible file size units.
+ */
+enum size_unit {
+	/** 512-byte blocks. */
+	SIZE_BLOCKS,
+	/** Single bytes. */
+	SIZE_BYTES,
+	/** Two-byte words. */
+	SIZE_WORDS,
+	/** Kibibytes. */
+	SIZE_KB,
+	/** Mebibytes. */
+	SIZE_MB,
+	/** Gibibytes. */
+	SIZE_GB,
+	/** Tebibytes. */
+	SIZE_TB,
+	/** Pebibytes. */
+	SIZE_PB,
+};
+
+struct expr {
+	/** The function that evaluates this expression. */
+	eval_fn *eval;
+
+	/** The left hand side of the expression. */
+	struct expr *lhs;
+	/** The right hand side of the expression. */
+	struct expr *rhs;
+
+	/** Whether this expression has no side effects. */
+	bool pure;
+	/** Whether this expression always evaluates to true. */
+	bool always_true;
+	/** Whether this expression always evaluates to false. */
+	bool always_false;
+
+	/** Estimated cost. */
+	double cost;
+	/** Estimated probability of success. */
+	double probability;
+	/** Number of times this predicate was executed. */
+	size_t evaluations;
+	/** Number of times this predicate succeeded. */
+	size_t successes;
+	/** Total time spent running this predicate. */
+	struct timespec elapsed;
+
+	/** The number of command line arguments for this expression. */
+	size_t argc;
+	/** The command line arguments comprising this expression. */
+	char **argv;
+
+	/** The optional comparison flag. */
+	enum cmp_flag cmp_flag;
+
+	/** The mode comparison flag. */
+	enum mode_cmp mode_cmp;
+	/** Mode to use for files. */
+	mode_t file_mode;
+	/** Mode to use for directories (different due to X). */
+	mode_t dir_mode;
+
+	/** The optional stat field to look at. */
+	enum bfs_stat_field stat_field;
+	/** The optional reference time. */
+	struct timespec reftime;
+	/** The optional time unit. */
+	enum time_unit time_unit;
+
+	/** The optional size unit. */
+	enum size_unit size_unit;
+
+	/** Optional device number for a target file. */
+	dev_t dev;
+	/** Optional inode number for a target file. */
+	ino_t ino;
+
+	/** File to output to. */
+	CFILE *cfile;
+
+	/** Optional compiled regex. */
+	regex_t *regex;
+
+	/** Optional exec command. */
+	struct bfs_exec *execbuf;
+
+	/** Optional printf command. */
+	struct bfs_printf *printf;
+
+	/** Optional integer data for this expression. */
+	long long idata;
+
+	/** Optional string data for this expression. */
+	const char *sdata;
+
+	/** The number of files this expression keeps open between evaluations. */
+	int persistent_fds;
+	/** The number of files this expression opens during evaluation. */
+	int ephemeral_fds;
+};
+
+/** Singleton true expression instance. */
+extern struct expr expr_true;
+/** Singleton false expression instance. */
+extern struct expr expr_false;
+
+/**
+ * Create a new expression.
+ */
+struct expr *new_expr(eval_fn *eval, size_t argc, char **argv);
+
+/**
+ * @return Whether expr is known to always quit.
+ */
+bool expr_never_returns(const struct expr *expr);
+
+/**
+ * @return The result of the comparison for this expression.
+ */
+bool expr_cmp(const struct expr *expr, long long n);
+
+/**
+ * Dump a parsed expression.
+ */
+void dump_expr(CFILE *cfile, const struct expr *expr, bool verbose);
+
+/**
+ * Free an expression tree.
+ */
+void free_expr(struct expr *expr);
+
+#endif // BFS_EXPR_H
+/****************************************************************************
+ * bfs                                                                      *
+ * Copyright (C) 2015-2019 Tavian Barnes <tavianator@tavianator.com>        *
+ *                                                                          *
+ * Permission to use, copy, modify, and/or distribute this software for any *
+ * purpose with or without fee is hereby granted.                           *
+ *                                                                          *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES *
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF         *
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR  *
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES   *
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN    *
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF  *
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.           *
+ ****************************************************************************/
+
+/**
+ * Constants about the bfs program itself.
+ */
+
+#ifndef BFS_H
+#define BFS_H
+
+#ifndef BFS_VERSION
+#	define BFS_VERSION "1.5"
+#endif
+
+#ifndef BFS_HOMEPAGE
+#	define BFS_HOMEPAGE "https://github.com/tavianator/bfs"
+#endif
+
+#endif // BFS_H
+/****************************************************************************
+ * bfs