1 files changed, 141 insertions, 0 deletions
diff --git a/src/main.c b/src/main.c
new file mode 100644
index 0000000..9dc96e4
--- /dev/null
+++ b/src/main.c
@@ -0,0 +1,141 @@
+/****************************************************************************
+ * bfs                                                                      *
+ * Copyright (C) 2015-2022 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.           *
+ ****************************************************************************/
+
+/**
+ * - main(): the entry point for bfs(1), a breadth-first version of find(1)
+ *     - main.c        (this file)
+ *
+ * - bfs_parse_cmdline(): parses the command line into an expression tree
+ *     - ctx.[ch]      (struct bfs_ctx, the overall bfs context)
+ *     - expr.h        (declares the expression tree nodes)
+ *     - parse.[ch]    (the parser itself)
+ *     - opt.[ch]      (the optimizer)
+ *
+ * - bfs_eval(): runs the expression on every file it sees
+ *     - eval.[ch]     (the main evaluation functions)
+ *     - exec.[ch]     (implements -exec[dir]/-ok[dir])
+ *     - printf.[ch]   (implements -[f]printf)
+ *
+ * - bftw(): used by bfs_eval() to walk the directory tree(s)
+ *     - bftw.[ch]     (an extended version of nftw(3))
+ *
+ * - Utilities:
+ *     - bfs.h         (constants about bfs itself)
+ *     - bar.[ch]      (a terminal status bar)
+ *     - color.[ch]    (for pretty terminal colors)
+ *     - darray.[ch]   (a dynamic array library)
+ *     - diag.[ch]     (formats diagnostic messages)
+ *     - dir.[ch]      (a directory API facade)
+ *     - dstring.[ch]  (a dynamic string library)
+ *     - fsade.[ch]    (a facade over non-standard filesystem features)
+ *     - mtab.[ch]     (parses the system's mount table)
+ *     - pwcache.[ch]  (a cache for the user/group tables)
+ *     - stat.[ch]     (wraps stat(), or statx() on Linux)
+ *     - trie.[ch]     (a trie set/map implementation)
+ *     - typo.[ch]     (fuzzy matching for typos)
+ *     - util.[ch]     (everything else)
+ *     - xregex.[ch]   (regular expression support)
+ *     - xspawn.[ch]   (spawns processes)
+ *     - xtime.[ch]    (date/time handling utilities)
+ */
+
+#include "ctx.h"
+#include "eval.h"
+#include "parse.h"
+#include "util.h"
+#include <errno.h>
+#include <fcntl.h>
+#include <locale.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+/**
+ * Check if a file descriptor is open.
+ */
+static bool isopen(int fd) {
+	return fcntl(fd, F_GETFD) >= 0 || errno != EBADF;
+}
+
+/**
+ * Open a file and redirect it to a particular descriptor.
+ */
+static int redirect(int fd, const char *path, int flags) {
+	int newfd = open(path, flags);
+	if (newfd < 0 || newfd == fd) {
+		return newfd;
+	}
+
+	int ret = dup2(newfd, fd);
+	close_quietly(newfd);
+	return ret;
+}
+
+/**
+ * Make sure the standard streams std{in,out,err} are open.  If they are not,
+ * future open() calls may use those file descriptors, and std{in,out,err} will
+ * use them unintentionally.
+ */
+static int open_std_streams(void) {
+#ifdef O_PATH
+	const int inflags = O_PATH, outflags = O_PATH;
+#else
+	// These are intentionally backwards so that bfs >&- still fails with EBADF
+	const int inflags = O_WRONLY, outflags = O_RDONLY;
+#endif
+
+	if (!isopen(STDERR_FILENO) && redirect(STDERR_FILENO, "/dev/null", outflags) < 0) {
+		return -1;
+	}
+	if (!isopen(STDOUT_FILENO) && redirect(STDOUT_FILENO, "/dev/null", outflags) < 0) {
+		perror("redirect()");
+		return -1;
+	}
+	if (!isopen(STDIN_FILENO) && redirect(STDIN_FILENO, "/dev/null", inflags) < 0) {
+		perror("redirect()");
+		return -1;
+	}
+
+	return 0;
+}
+
+/**
+ * bfs entry point.
+ */
+int main(int argc, char *argv[]) {
+	int ret = EXIT_FAILURE;
+
+	// Make sure the standard streams are open
+	if (open_std_streams() != 0) {
+		goto done;
+	}
+
+	// Use the system locale instead of "C"
+	setlocale(LC_ALL, "");
+
+	struct bfs_ctx *ctx = bfs_parse_cmdline(argc, argv);
+	if (ctx) {
+		ret = bfs_eval(ctx);
+	}
+
+	if (bfs_ctx_free(ctx) != 0 && ret == EXIT_SUCCESS) {
+		ret = EXIT_FAILURE;
+	}
+
+done:
+	return ret;
+}