Fix: consumerd: unbalanced subbuffer 'get' when checking operation availability
[lttng-tools.git] / src / common / fd-tracker / utils.c
1 /*
2 * Copyright (C) 2018 Jérémie Galarneau <jeremie.galarneau@efficios.com>
3 *
4 * SPDX-License-Identifier: GPL-2.0-only
5 *
6 */
7
8 #include <common/error.h>
9 #include <common/fd-tracker/utils.h>
10 #include <common/utils.h>
11 #include <lttng/constant.h>
12 #include <stdio.h>
13 #include <stdlib.h>
14 #include <unistd.h>
15
16 static
17 int open_pipe_cloexec(void *data, int *fds)
18 {
19 return utils_create_pipe_cloexec(fds);
20 }
21
22 static
23 int close_pipe(void *data, int *pipe)
24 {
25 utils_close_pipe(pipe);
26 pipe[0] = pipe[1] = -1;
27 return 0;
28 }
29
30 LTTNG_HIDDEN
31 int fd_tracker_util_close_fd(void *unused, int *fd)
32 {
33 return close(*fd);
34 }
35
36 LTTNG_HIDDEN
37 int fd_tracker_util_pipe_open_cloexec(
38 struct fd_tracker *tracker, const char *name, int *pipe)
39 {
40 int ret;
41 const char *name_prefix;
42 char *names[2];
43
44 name_prefix = name ? name : "Unknown pipe";
45 ret = asprintf(&names[0], "%s (read end)", name_prefix);
46 if (ret < 0) {
47 goto end;
48 }
49 ret = asprintf(&names[1], "%s (write end)", name_prefix);
50 if (ret < 0) {
51 goto end;
52 }
53
54 ret = fd_tracker_open_unsuspendable_fd(tracker, pipe,
55 (const char **) names, 2, open_pipe_cloexec, NULL);
56 free(names[0]);
57 free(names[1]);
58 end:
59 return ret;
60 }
61
62 LTTNG_HIDDEN
63 int fd_tracker_util_pipe_close(struct fd_tracker *tracker, int *pipe)
64 {
65 return fd_tracker_close_unsuspendable_fd(
66 tracker, pipe, 2, close_pipe, NULL);
67 }
68
69 struct open_directory_handle_args {
70 const struct lttng_directory_handle *in_handle;
71 struct lttng_directory_handle *ret_handle;
72 const char *path;
73 };
74
75 static
76 int open_directory_handle(void *_args, int *out_fds)
77 {
78 int ret = 0;
79 struct open_directory_handle_args *args = _args;
80 struct lttng_directory_handle *new_handle = NULL;
81
82 new_handle = args->in_handle ?
83 lttng_directory_handle_create_from_handle(
84 args->path, args->in_handle) :
85 lttng_directory_handle_create(args->path);
86 if (!new_handle) {
87 ret = -errno;
88 goto end;
89 }
90
91 args->ret_handle = new_handle;
92
93 /*
94 * Reserved to indicate that the handle does not use a handle; there is
95 * nothing to track. We want to indicate an error to the fd-tracker so
96 * that it doesn't attempt to track the file descriptor, but also want
97 * the caller to retrieve the newly-created handle.
98 *
99 * Calling this a hack is a fair assessment.
100 */
101 if (!lttng_directory_handle_uses_fd(new_handle)) {
102 ret = ENOTSUP;
103 } else {
104 #ifdef HAVE_DIRFD
105 *out_fds = new_handle->dirfd;
106 #else
107 abort();
108 #endif
109
110 }
111 end:
112 return ret;
113 }
114
115 #ifdef HAVE_DIRFD
116 static
117 int fd_close(void *unused, int *in_fds)
118 {
119 const int ret = close(in_fds[0]);
120
121 in_fds[0] = -1;
122 return ret;
123 }
124
125 static
126 void directory_handle_destroy(
127 struct lttng_directory_handle *handle, void *data)
128 {
129 struct fd_tracker *tracker = data;
130 const int ret = fd_tracker_close_unsuspendable_fd(
131 tracker, &handle->dirfd, 1, fd_close, NULL);
132
133 if (ret) {
134 ERR("Failed to untrack directory handle file descriptor");
135 }
136 }
137 #endif
138
139 LTTNG_HIDDEN
140 struct lttng_directory_handle *fd_tracker_create_directory_handle(
141 struct fd_tracker *tracker, const char *path)
142 {
143 return fd_tracker_create_directory_handle_from_handle(
144 tracker, NULL, path);
145 }
146
147 LTTNG_HIDDEN
148 struct lttng_directory_handle *fd_tracker_create_directory_handle_from_handle(
149 struct fd_tracker *tracker,
150 struct lttng_directory_handle *in_handle,
151 const char *path)
152 {
153 int ret;
154 int dirfd = -1;
155 char *handle_name = NULL;
156 char cwd_path[LTTNG_PATH_MAX] = "working directory";
157 struct lttng_directory_handle *new_handle = NULL;
158 struct open_directory_handle_args open_args = {
159 .in_handle = in_handle,
160 .path = path,
161 };
162
163 if (!path) {
164 if (!getcwd(cwd_path, sizeof(cwd_path))) {
165 PERROR("Failed to get current working directory to name directory handle");
166 goto end;
167 }
168 }
169
170 ret = asprintf(&handle_name, "Directory handle to %s",
171 path ? path : cwd_path);
172 if (ret < 0) {
173 PERROR("Failed to format directory handle name");
174 goto end;
175 }
176
177 ret = fd_tracker_open_unsuspendable_fd(tracker, &dirfd,
178 (const char **) &handle_name, 1, open_directory_handle,
179 &open_args);
180 if (ret && ret != ENOTSUP) {
181 ERR("Failed to open directory handle to %s through the fd tracker", path ? path : cwd_path);
182 }
183 new_handle = open_args.ret_handle;
184
185 #ifdef HAVE_DIRFD
186 new_handle->destroy_cb = directory_handle_destroy;
187 new_handle->destroy_cb_data = tracker;
188 #endif
189 end:
190 free(handle_name);
191 return new_handle;
192 }
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