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e822f505 MD |
1 | /* |
2 | * Copyright (C) 2009 Pierre-Marc Fournier | |
3 | * Copyright (C) 2011 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> | |
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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. | |
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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> |
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25 | #include <sched.h> |
26 | #include <stdarg.h> | |
fbca6b62 | 27 | #include "usterr.h" |
2d99476b | 28 | |
4318ae1b | 29 | #include <lttng/ust.h> |
e822f505 | 30 | |
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31 | pid_t fork(void) |
32 | { | |
33 | static pid_t (*plibc_func)(void) = NULL; | |
7f0aeeba | 34 | sigset_t sigset; |
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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"); | |
2c10b7fd | 41 | return -1; |
2d99476b PMF |
42 | } |
43 | } | |
44 | ||
7f0aeeba | 45 | ust_before_fork(&sigset); |
df793c55 | 46 | /* Do the real fork */ |
2d99476b | 47 | retval = plibc_func(); |
e822f505 | 48 | if (retval == 0) { |
df793c55 | 49 | /* child */ |
7f0aeeba | 50 | ust_after_fork_child(&sigset); |
e822f505 | 51 | } else { |
7f0aeeba | 52 | ust_after_fork_parent(&sigset); |
df793c55 | 53 | } |
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54 | return retval; |
55 | } | |
97b042a3 | 56 | |
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57 | #ifdef __linux__ |
58 | ||
59 | struct user_desc; | |
60 | ||
e822f505 | 61 | struct ustfork_clone_info { |
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62 | int (*fn)(void *); |
63 | void *arg; | |
7f0aeeba | 64 | sigset_t sigset; |
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65 | }; |
66 | ||
67 | static int clone_fn(void *arg) | |
68 | { | |
e822f505 | 69 | struct ustfork_clone_info *info = (struct ustfork_clone_info *) arg; |
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70 | |
71 | /* clone is now done and we are in child */ | |
7f0aeeba | 72 | ust_after_fork_child(&info->sigset); |
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73 | return info->fn(info->arg); |
74 | } | |
75 | ||
76 | int clone(int (*fn)(void *), void *child_stack, int flags, void *arg, ...) | |
77 | { | |
e822f505 MD |
78 | static int (*plibc_func)(int (*fn)(void *), void *child_stack, |
79 | int flags, void *arg, pid_t *ptid, | |
80 | struct user_desc *tls, pid_t *ctid) = NULL; | |
81 | /* var args */ | |
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82 | pid_t *ptid; |
83 | struct user_desc *tls; | |
84 | pid_t *ctid; | |
e822f505 | 85 | /* end of var args */ |
616ed36a | 86 | va_list ap; |
e822f505 | 87 | int retval; |
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88 | |
89 | va_start(ap, arg); | |
90 | ptid = va_arg(ap, pid_t *); | |
91 | tls = va_arg(ap, struct user_desc *); | |
92 | ctid = va_arg(ap, pid_t *); | |
93 | va_end(ap); | |
94 | ||
e822f505 | 95 | if (plibc_func == NULL) { |
616ed36a | 96 | plibc_func = dlsym(RTLD_NEXT, "clone"); |
e822f505 MD |
97 | if (plibc_func == NULL) { |
98 | fprintf(stderr, "libustfork: unable to find \"clone\" symbol.\n"); | |
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99 | return -1; |
100 | } | |
101 | } | |
102 | ||
e822f505 MD |
103 | if (flags & CLONE_VM) { |
104 | /* | |
105 | * Creating a thread, no need to intervene, just pass on | |
106 | * the arguments. | |
107 | */ | |
108 | retval = plibc_func(fn, child_stack, flags, arg, ptid, | |
109 | tls, ctid); | |
110 | } else { | |
111 | /* Creating a real process, we need to intervene. */ | |
02db7125 | 112 | struct ustfork_clone_info info = { fn = fn, arg = arg }; |
616ed36a | 113 | |
7f0aeeba | 114 | ust_before_fork(&info.sigset); |
e822f505 MD |
115 | retval = plibc_func(clone_fn, child_stack, flags, &info, |
116 | ptid, tls, ctid); | |
117 | /* The child doesn't get here. */ | |
7f0aeeba | 118 | ust_after_fork_parent(&info.sigset); |
616ed36a | 119 | } |
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120 | return retval; |
121 | } | |
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122 | |
123 | #elif defined (__FreeBSD__) | |
124 | ||
125 | pid_t rfork(int flags) | |
126 | { | |
127 | static pid_t (*plibc_func)(void) = NULL; | |
128 | sigset_t sigset; | |
129 | pid_t retval; | |
130 | ||
131 | if (plibc_func == NULL) { | |
132 | plibc_func = dlsym(RTLD_NEXT, "rfork"); | |
133 | if (plibc_func == NULL) { | |
134 | fprintf(stderr, "libustfork: unable to find \"rfork\" symbol\n"); | |
135 | return -1; | |
136 | } | |
137 | } | |
138 | ||
139 | ust_before_fork(&sigset); | |
140 | /* Do the real rfork */ | |
141 | retval = plibc_func(); | |
142 | if (retval == 0) { | |
143 | /* child */ | |
144 | ust_after_fork_child(&sigset); | |
145 | } else { | |
146 | ust_after_fork_parent(&sigset); | |
147 | } | |
148 | return retval; | |
149 | } | |
150 | ||
151 | /* | |
152 | * On BSD, no need to override vfork, because it runs in the context of | |
153 | * the parent, with parent waiting until execve or exit is executed in | |
154 | * the child. | |
155 | */ | |
156 | ||
157 | #else | |
158 | #warning "Unknown OS. You might want to ensure that fork/clone/vfork/fork handling is complete." | |
159 | #endif |