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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. | |
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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 | |
f02baefb | 21 | #include <lttng/ust-dlfcn.h> |
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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> | |
eb2b066f | 27 | #include <errno.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"); | |
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 | |
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58 | int daemon(int nochdir, int noclose) |
59 | { | |
60 | static int (*plibc_func)(int nochdir, int noclose) = NULL; | |
61 | sigset_t sigset; | |
62 | int retval; | |
63 | ||
64 | if (plibc_func == NULL) { | |
65 | plibc_func = dlsym(RTLD_NEXT, "daemon"); | |
66 | if (plibc_func == NULL) { | |
67 | fprintf(stderr, "libustfork: unable to find \"daemon\" symbol\n"); | |
68 | errno = ENOSYS; | |
69 | return -1; | |
70 | } | |
71 | } | |
72 | ||
73 | ust_before_fork(&sigset); | |
74 | /* Do the real daemon call */ | |
75 | retval = plibc_func(nochdir, noclose); | |
76 | if (retval == 0) { | |
77 | /* child, parent called _exit() directly */ | |
78 | ust_after_fork_child(&sigset); | |
79 | } else { | |
80 | /* on error in the parent */ | |
81 | ust_after_fork_parent(&sigset); | |
82 | } | |
83 | return retval; | |
84 | } | |
85 | ||
939c89cb MD |
86 | #ifdef __linux__ |
87 | ||
88 | struct user_desc; | |
89 | ||
e822f505 | 90 | struct ustfork_clone_info { |
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91 | int (*fn)(void *); |
92 | void *arg; | |
7f0aeeba | 93 | sigset_t sigset; |
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94 | }; |
95 | ||
96 | static int clone_fn(void *arg) | |
97 | { | |
e822f505 | 98 | struct ustfork_clone_info *info = (struct ustfork_clone_info *) arg; |
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99 | |
100 | /* clone is now done and we are in child */ | |
7f0aeeba | 101 | ust_after_fork_child(&info->sigset); |
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102 | return info->fn(info->arg); |
103 | } | |
104 | ||
105 | int clone(int (*fn)(void *), void *child_stack, int flags, void *arg, ...) | |
106 | { | |
e822f505 MD |
107 | static int (*plibc_func)(int (*fn)(void *), void *child_stack, |
108 | int flags, void *arg, pid_t *ptid, | |
109 | struct user_desc *tls, pid_t *ctid) = NULL; | |
110 | /* var args */ | |
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111 | pid_t *ptid; |
112 | struct user_desc *tls; | |
113 | pid_t *ctid; | |
e822f505 | 114 | /* end of var args */ |
616ed36a | 115 | va_list ap; |
e822f505 | 116 | int retval; |
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117 | |
118 | va_start(ap, arg); | |
119 | ptid = va_arg(ap, pid_t *); | |
120 | tls = va_arg(ap, struct user_desc *); | |
121 | ctid = va_arg(ap, pid_t *); | |
122 | va_end(ap); | |
123 | ||
e822f505 | 124 | if (plibc_func == NULL) { |
616ed36a | 125 | plibc_func = dlsym(RTLD_NEXT, "clone"); |
e822f505 MD |
126 | if (plibc_func == NULL) { |
127 | fprintf(stderr, "libustfork: unable to find \"clone\" symbol.\n"); | |
3678c8aa | 128 | errno = ENOSYS; |
616ed36a PMF |
129 | return -1; |
130 | } | |
131 | } | |
132 | ||
e822f505 MD |
133 | if (flags & CLONE_VM) { |
134 | /* | |
135 | * Creating a thread, no need to intervene, just pass on | |
136 | * the arguments. | |
137 | */ | |
138 | retval = plibc_func(fn, child_stack, flags, arg, ptid, | |
139 | tls, ctid); | |
140 | } else { | |
141 | /* Creating a real process, we need to intervene. */ | |
3fd2b913 | 142 | struct ustfork_clone_info info = { .fn = fn, .arg = arg }; |
616ed36a | 143 | |
7f0aeeba | 144 | ust_before_fork(&info.sigset); |
e822f505 MD |
145 | retval = plibc_func(clone_fn, child_stack, flags, &info, |
146 | ptid, tls, ctid); | |
147 | /* The child doesn't get here. */ | |
7f0aeeba | 148 | ust_after_fork_parent(&info.sigset); |
616ed36a | 149 | } |
616ed36a PMF |
150 | return retval; |
151 | } | |
939c89cb MD |
152 | |
153 | #elif defined (__FreeBSD__) | |
154 | ||
155 | pid_t rfork(int flags) | |
156 | { | |
157 | static pid_t (*plibc_func)(void) = NULL; | |
158 | sigset_t sigset; | |
159 | pid_t retval; | |
160 | ||
161 | if (plibc_func == NULL) { | |
162 | plibc_func = dlsym(RTLD_NEXT, "rfork"); | |
163 | if (plibc_func == NULL) { | |
164 | fprintf(stderr, "libustfork: unable to find \"rfork\" symbol\n"); | |
3678c8aa | 165 | errno = ENOSYS; |
939c89cb MD |
166 | return -1; |
167 | } | |
168 | } | |
169 | ||
170 | ust_before_fork(&sigset); | |
171 | /* Do the real rfork */ | |
172 | retval = plibc_func(); | |
173 | if (retval == 0) { | |
174 | /* child */ | |
175 | ust_after_fork_child(&sigset); | |
176 | } else { | |
177 | ust_after_fork_parent(&sigset); | |
178 | } | |
179 | return retval; | |
180 | } | |
181 | ||
182 | /* | |
183 | * On BSD, no need to override vfork, because it runs in the context of | |
184 | * the parent, with parent waiting until execve or exit is executed in | |
185 | * the child. | |
186 | */ | |
187 | ||
188 | #else | |
189 | #warning "Unknown OS. You might want to ensure that fork/clone/vfork/fork handling is complete." | |
190 | #endif |