summaryrefslogtreecommitdiffstats
path: root/src/main.c
blob: 16a2576807e2039ef487abb129496633f99f2559 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
// Copyright © Tavian Barnes <tavianator@tavianator.com>
// SPDX-License-Identifier: 0BSD

/**
 * - 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:
 *     - alloc.[ch]    (memory allocation)
 *     - atomic.h      (atomic operations)
 *     - bar.[ch]      (a terminal status bar)
 *     - bit.h         (bit manipulation)
 *     - bfstd.[ch]    (standard library wrappers/polyfills)
 *     - color.[ch]    (for pretty terminal colors)
 *     - config.h      (configuration and feature/platform detection)
 *     - 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)
 *     - ioq.[ch]      (an async I/O queue)
 *     - list.h        (linked list macros)
 *     - mtab.[ch]     (parses the system's mount table)
 *     - pwcache.[ch]  (a cache for the user/group tables)
 *     - sanity.h      (sanitizer interfaces)
 *     - stat.[ch]     (wraps stat(), or statx() on Linux)
 *     - thread.h      (multi-threading)
 *     - trie.[ch]     (a trie set/map implementation)
 *     - typo.[ch]     (fuzzy matching for typos)
 *     - xregex.[ch]   (regular expression support)
 *     - xspawn.[ch]   (spawns processes)
 *     - xtime.[ch]    (date/time handling utilities)
 */

#include "bfstd.h"
#include "config.h"
#include "ctx.h"
#include "eval.h"
#include "parse.h"
#include <errno.h>
#include <fcntl.h>
#include <locale.h>
#include <stdio.h>
#include <stdlib.h>
#include <time.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[]) {
	// Make sure the standard streams are open
	if (open_std_streams() != 0) {
		return EXIT_FAILURE;
	}

	// Use the system locale instead of "C"
	int locale_err = 0;
	if (!setlocale(LC_ALL, "")) {
		locale_err = errno;
	}

	// Apply the environment's timezone
	tzset();

	// Parse the command line
	struct bfs_ctx *ctx = bfs_parse_cmdline(argc, argv);
	if (!ctx) {
		return EXIT_FAILURE;
	}

	// Warn if setlocale() failed, unless there's no expression to evaluate
	if (locale_err && ctx->warn && ctx->expr) {
		bfs_warning(ctx, "Failed to set locale: %s\n\n", xstrerror(locale_err));
	}

	// Walk the file system tree, evaluating the expression on each file
	int ret = bfs_eval(ctx);

	// Free the parsed command line, and detect any last-minute errors
	if (bfs_ctx_free(ctx) != 0 && ret == EXIT_SUCCESS) {
		ret = EXIT_FAILURE;
	}

	return ret;
}