summaryrefslogtreecommitdiff
path: root/libbb/recursive_action.c
blob: b1c4bfad7ccff508e1322bd79c3af9e84e3bcec9 (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
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
/* vi: set sw=4 ts=4: */
/*
 * Utility routines.
 *
 * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
 *
 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
 */
#include "libbb.h"

#undef DEBUG_RECURS_ACTION

/*
 * Walk down all the directories under the specified
 * location, and do something (something specified
 * by the fileAction and dirAction function pointers).
 *
 * Unfortunately, while nftw(3) could replace this and reduce
 * code size a bit, nftw() wasn't supported before GNU libc 2.1,
 * and so isn't sufficiently portable to take over since glibc2.1
 * is so stinking huge.
 */

static int FAST_FUNC true_action(struct recursive_state *state UNUSED_PARAM,
		const char *fileName UNUSED_PARAM,
		struct stat *statbuf UNUSED_PARAM)
{
	return TRUE;
}

/* fileName is (l)stat'ed (depending on ACTION_FOLLOWLINKS[_L0]).
 *
 * If it is a file: fileAction in run on it, its return value is returned.
 *
 * In case we are in a recursive invocation (see below):
 * normally, fileAction should return 1 (TRUE) to indicate that
 * everything is okay and processing should continue.
 * fileAction return value of 0 (FALSE) on any file in directory will make
 * recursive_action() also return 0, but it doesn't stop directory traversal
 * (fileAction/dirAction will be called on each file).
 *
 * [TODO: maybe introduce -1 to mean "stop traversal NOW and return"]
 *
 * If it is a directory:
 *
 * If !ACTION_RECURSE, dirAction is called and its
 * return value is returned from recursive_action(). No recursion.
 *
 * If ACTION_RECURSE, directory is opened, and recursive_action() is called
 * on each file/subdirectory.
 * If any one of these calls returns 0, current recursive_action() returns 0.
 *
 * If !ACTION_DEPTHFIRST, dirAction is called before recurse.
 * Return value of 0 (FALSE) is an error: prevents recursion,
 * the warning is printed (unless ACTION_QUIET) and recursive_action() returns 0.
 * Return value of 2 (SKIP) prevents recursion, instead recursive_action()
 * returns 1 (TRUE, no error).
 *
 * If ACTION_DEPTHFIRST, dirAction is called after recurse.
 * If it returns 0, the warning is printed and recursive_action() returns 0.
 *
 * ACTION_FOLLOWLINKS mainly controls handling of links to dirs.
 * 0: lstat(statbuf). Calls fileAction on link name even if points to dir.
 * 1: stat(statbuf). Calls dirAction and optionally recurse on link to dir.
 */

static int recursive_action1(recursive_state_t *state, const char *fileName)
{
	struct stat statbuf;
	unsigned follow;
	int status;
	DIR *dir;
	struct dirent *next;

	follow = ACTION_FOLLOWLINKS;
	if (state->depth == 0)
		follow = ACTION_FOLLOWLINKS | ACTION_FOLLOWLINKS_L0;
	follow &= state->flags;
	status = (follow ? stat : lstat)(fileName, &statbuf);
	if (status < 0) {
#ifdef DEBUG_RECURS_ACTION
		bb_error_msg("status=%d flags=%x", status, state->flags);
#endif
		if ((state->flags & ACTION_DANGLING_OK)
		 && errno == ENOENT
		 && lstat(fileName, &statbuf) == 0
		) {
			/* Dangling link */
			return state->fileAction(state, fileName, &statbuf);
		}
		goto done_nak_warn;
	}

	/* If S_ISLNK(m), then we know that !S_ISDIR(m).
	 * Then we can skip checking first part: if it is true, then
	 * (!dir) is also true! */
	if ( /* (!(state->flags & ACTION_FOLLOWLINKS) && S_ISLNK(statbuf.st_mode)) || */
	 !S_ISDIR(statbuf.st_mode)
	) {
		return state->fileAction(state, fileName, &statbuf);
	}

	/* It's a directory (or a link to one, and followLinks is set) */

	if (!(state->flags & ACTION_RECURSE)) {
		return state->dirAction(state, fileName, &statbuf);
	}

	if (!(state->flags & ACTION_DEPTHFIRST)) {
		status = state->dirAction(state, fileName, &statbuf);
		if (status == FALSE)
			goto done_nak_warn;
		if (status == SKIP)
			return TRUE;
	}

	dir = opendir(fileName);
	if (!dir) {
		/* findutils-4.1.20 reports this */
		/* (i.e. it doesn't silently return with exit code 1) */
		/* To trigger: "find -exec rm -rf {} \;" */
		goto done_nak_warn;
	}
	status = TRUE;
	while ((next = readdir(dir)) != NULL) {
		char *nextFile;
		int s;

		nextFile = concat_subpath_file(fileName, next->d_name);
		if (nextFile == NULL)
			continue;

		/* process every file (NB: ACTION_RECURSE is set in flags) */
		state->depth++;
		s = recursive_action1(state, nextFile);
		if (s == FALSE)
			status = FALSE;
		free(nextFile);
		state->depth--;

//#define RECURSE_RESULT_ABORT -1
//		if (s == RECURSE_RESULT_ABORT) {
//			closedir(dir);
//			return s;
//		}
	}
	closedir(dir);

	if (state->flags & ACTION_DEPTHFIRST) {
		if (!state->dirAction(state, fileName, &statbuf))
			goto done_nak_warn;
	}

	return status;

 done_nak_warn:
	if (!(state->flags & ACTION_QUIET))
		bb_simple_perror_msg(fileName);
	return FALSE;
}

int FAST_FUNC recursive_action(const char *fileName,
		unsigned flags,
		int FAST_FUNC (*fileAction)(struct recursive_state *state, const char *fileName, struct stat* statbuf),
		int FAST_FUNC  (*dirAction)(struct recursive_state *state, const char *fileName, struct stat* statbuf),
		void *userData)
{
	/* Keeping a part of variables of recusive descent in a "state structure"
	 * instead of passing ALL of them down as parameters of recursive_action1()
	 * relieves register pressure, both in recursive_action1()
	 * and in every file/dirAction().
	 */
	recursive_state_t state;
	state.flags = flags;
	state.depth = 0;
	state.userData = userData;
	state.fileAction = fileAction ? fileAction : true_action;
	state.dirAction  =  dirAction ?  dirAction : true_action;

	return recursive_action1(&state, fileName);
}