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e822f505 MD |
1 | /* |
2 | * Copyright (C) 2009 Pierre-Marc Fournier | |
3678c8aa | 3 | * Copyright (C) 2011-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> |
2d99476b PMF |
4 | * |
5 | * This library is free software; you can redistribute it and/or | |
6 | * modify it under the terms of the GNU Lesser General Public | |
e822f505 MD |
7 | * License as published by the Free Software Foundation; version 2.1 of |
8 | * the License. | |
2d99476b PMF |
9 | * |
10 | * This library is distributed in the hope that it will be useful, | |
11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
13 | * Lesser General Public License for more details. | |
14 | * | |
15 | * You should have received a copy of the GNU Lesser General Public | |
16 | * License along with this library; if not, write to the Free Software | |
17 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | |
18 | */ | |
19 | ||
20 | #define _GNU_SOURCE | |
21 | #include <dlfcn.h> | |
22 | #include <unistd.h> | |
23 | #include <stdio.h> | |
df793c55 | 24 | #include <signal.h> |
616ed36a PMF |
25 | #include <sched.h> |
26 | #include <stdarg.h> | |
fbca6b62 | 27 | #include "usterr.h" |
2d99476b | 28 | |
4318ae1b | 29 | #include <lttng/ust.h> |
e822f505 | 30 | |
2d99476b PMF |
31 | pid_t fork(void) |
32 | { | |
33 | static pid_t (*plibc_func)(void) = NULL; | |
7f0aeeba | 34 | sigset_t sigset; |
2d99476b PMF |
35 | pid_t retval; |
36 | ||
e822f505 | 37 | if (plibc_func == NULL) { |
2d99476b | 38 | plibc_func = dlsym(RTLD_NEXT, "fork"); |
e822f505 MD |
39 | if (plibc_func == NULL) { |
40 | fprintf(stderr, "libustfork: unable to find \"fork\" symbol\n"); | |
3678c8aa | 41 | errno = ENOSYS; |
2c10b7fd | 42 | return -1; |
2d99476b PMF |
43 | } |
44 | } | |
45 | ||
7f0aeeba | 46 | ust_before_fork(&sigset); |
df793c55 | 47 | /* Do the real fork */ |
2d99476b | 48 | retval = plibc_func(); |
e822f505 | 49 | if (retval == 0) { |
df793c55 | 50 | /* child */ |
7f0aeeba | 51 | ust_after_fork_child(&sigset); |
e822f505 | 52 | } else { |
7f0aeeba | 53 | ust_after_fork_parent(&sigset); |
df793c55 | 54 | } |
2d99476b PMF |
55 | return retval; |
56 | } | |
97b042a3 | 57 | |
939c89cb MD |
58 | #ifdef __linux__ |
59 | ||
60 | struct user_desc; | |
61 | ||
e822f505 | 62 | struct ustfork_clone_info { |
616ed36a PMF |
63 | int (*fn)(void *); |
64 | void *arg; | |
7f0aeeba | 65 | sigset_t sigset; |
616ed36a PMF |
66 | }; |
67 | ||
68 | static int clone_fn(void *arg) | |
69 | { | |
e822f505 | 70 | struct ustfork_clone_info *info = (struct ustfork_clone_info *) arg; |
616ed36a PMF |
71 | |
72 | /* clone is now done and we are in child */ | |
7f0aeeba | 73 | ust_after_fork_child(&info->sigset); |
616ed36a PMF |
74 | return info->fn(info->arg); |
75 | } | |
76 | ||
77 | int clone(int (*fn)(void *), void *child_stack, int flags, void *arg, ...) | |
78 | { | |
e822f505 MD |
79 | static int (*plibc_func)(int (*fn)(void *), void *child_stack, |
80 | int flags, void *arg, pid_t *ptid, | |
81 | struct user_desc *tls, pid_t *ctid) = NULL; | |
82 | /* var args */ | |
616ed36a PMF |
83 | pid_t *ptid; |
84 | struct user_desc *tls; | |
85 | pid_t *ctid; | |
e822f505 | 86 | /* end of var args */ |
616ed36a | 87 | va_list ap; |
e822f505 | 88 | int retval; |
616ed36a PMF |
89 | |
90 | va_start(ap, arg); | |
91 | ptid = va_arg(ap, pid_t *); | |
92 | tls = va_arg(ap, struct user_desc *); | |
93 | ctid = va_arg(ap, pid_t *); | |
94 | va_end(ap); | |
95 | ||
e822f505 | 96 | if (plibc_func == NULL) { |
616ed36a | 97 | plibc_func = dlsym(RTLD_NEXT, "clone"); |
e822f505 MD |
98 | if (plibc_func == NULL) { |
99 | fprintf(stderr, "libustfork: unable to find \"clone\" symbol.\n"); | |
3678c8aa | 100 | errno = ENOSYS; |
616ed36a PMF |
101 | return -1; |
102 | } | |
103 | } | |
104 | ||
e822f505 MD |
105 | if (flags & CLONE_VM) { |
106 | /* | |
107 | * Creating a thread, no need to intervene, just pass on | |
108 | * the arguments. | |
109 | */ | |
110 | retval = plibc_func(fn, child_stack, flags, arg, ptid, | |
111 | tls, ctid); | |
112 | } else { | |
113 | /* Creating a real process, we need to intervene. */ | |
02db7125 | 114 | struct ustfork_clone_info info = { fn = fn, arg = arg }; |
616ed36a | 115 | |
7f0aeeba | 116 | ust_before_fork(&info.sigset); |
e822f505 MD |
117 | retval = plibc_func(clone_fn, child_stack, flags, &info, |
118 | ptid, tls, ctid); | |
119 | /* The child doesn't get here. */ | |
7f0aeeba | 120 | ust_after_fork_parent(&info.sigset); |
616ed36a | 121 | } |
616ed36a PMF |
122 | return retval; |
123 | } | |
939c89cb MD |
124 | |
125 | #elif defined (__FreeBSD__) | |
126 | ||
127 | pid_t rfork(int flags) | |
128 | { | |
129 | static pid_t (*plibc_func)(void) = NULL; | |
130 | sigset_t sigset; | |
131 | pid_t retval; | |
132 | ||
133 | if (plibc_func == NULL) { | |
134 | plibc_func = dlsym(RTLD_NEXT, "rfork"); | |
135 | if (plibc_func == NULL) { | |
136 | fprintf(stderr, "libustfork: unable to find \"rfork\" symbol\n"); | |
3678c8aa | 137 | errno = ENOSYS; |
939c89cb MD |
138 | return -1; |
139 | } | |
140 | } | |
141 | ||
142 | ust_before_fork(&sigset); | |
143 | /* Do the real rfork */ | |
144 | retval = plibc_func(); | |
145 | if (retval == 0) { | |
146 | /* child */ | |
147 | ust_after_fork_child(&sigset); | |
148 | } else { | |
149 | ust_after_fork_parent(&sigset); | |
150 | } | |
151 | return retval; | |
152 | } | |
153 | ||
154 | /* | |
155 | * On BSD, no need to override vfork, because it runs in the context of | |
156 | * the parent, with parent waiting until execve or exit is executed in | |
157 | * the child. | |
158 | */ | |
159 | ||
160 | #else | |
161 | #warning "Unknown OS. You might want to ensure that fork/clone/vfork/fork handling is complete." | |
162 | #endif |