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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 | |
99912014 MD |
31 | struct user_desc; |
32 | ||
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33 | pid_t fork(void) |
34 | { | |
35 | static pid_t (*plibc_func)(void) = NULL; | |
7f0aeeba | 36 | sigset_t sigset; |
2d99476b PMF |
37 | pid_t retval; |
38 | ||
e822f505 | 39 | if (plibc_func == NULL) { |
2d99476b | 40 | plibc_func = dlsym(RTLD_NEXT, "fork"); |
e822f505 MD |
41 | if (plibc_func == NULL) { |
42 | fprintf(stderr, "libustfork: unable to find \"fork\" symbol\n"); | |
2c10b7fd | 43 | return -1; |
2d99476b PMF |
44 | } |
45 | } | |
46 | ||
7f0aeeba | 47 | ust_before_fork(&sigset); |
df793c55 | 48 | /* Do the real fork */ |
2d99476b | 49 | retval = plibc_func(); |
e822f505 | 50 | if (retval == 0) { |
df793c55 | 51 | /* child */ |
7f0aeeba | 52 | ust_after_fork_child(&sigset); |
e822f505 | 53 | } else { |
7f0aeeba | 54 | ust_after_fork_parent(&sigset); |
df793c55 | 55 | } |
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56 | return retval; |
57 | } | |
97b042a3 | 58 | |
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59 | int daemon(int nochdir, int noclose) |
60 | { | |
61 | static int (*plibc_func)(int nochdir, int noclose) = NULL; | |
62 | sigset_t sigset; | |
63 | int retval; | |
64 | ||
65 | if (plibc_func == NULL) { | |
66 | plibc_func = dlsym(RTLD_NEXT, "daemon"); | |
67 | if (plibc_func == NULL) { | |
68 | fprintf(stderr, "libustfork: unable to find \"daemon\" symbol\n"); | |
69 | errno = ENOSYS; | |
70 | return -1; | |
71 | } | |
72 | } | |
73 | ||
74 | ust_before_fork(&sigset); | |
75 | /* Do the real daemon call */ | |
76 | retval = plibc_func(nochdir, noclose); | |
77 | if (retval == 0) { | |
78 | /* child, parent called _exit() directly */ | |
79 | ust_after_fork_child(&sigset); | |
80 | } else { | |
81 | /* on error in the parent */ | |
82 | ust_after_fork_parent(&sigset); | |
83 | } | |
84 | return retval; | |
85 | } | |
86 | ||
e822f505 | 87 | struct ustfork_clone_info { |
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88 | int (*fn)(void *); |
89 | void *arg; | |
7f0aeeba | 90 | sigset_t sigset; |
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91 | }; |
92 | ||
93 | static int clone_fn(void *arg) | |
94 | { | |
e822f505 | 95 | struct ustfork_clone_info *info = (struct ustfork_clone_info *) arg; |
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96 | |
97 | /* clone is now done and we are in child */ | |
7f0aeeba | 98 | ust_after_fork_child(&info->sigset); |
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99 | return info->fn(info->arg); |
100 | } | |
101 | ||
102 | int clone(int (*fn)(void *), void *child_stack, int flags, void *arg, ...) | |
103 | { | |
e822f505 MD |
104 | static int (*plibc_func)(int (*fn)(void *), void *child_stack, |
105 | int flags, void *arg, pid_t *ptid, | |
106 | struct user_desc *tls, pid_t *ctid) = NULL; | |
107 | /* var args */ | |
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108 | pid_t *ptid; |
109 | struct user_desc *tls; | |
110 | pid_t *ctid; | |
e822f505 | 111 | /* end of var args */ |
616ed36a | 112 | va_list ap; |
e822f505 | 113 | int retval; |
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114 | |
115 | va_start(ap, arg); | |
116 | ptid = va_arg(ap, pid_t *); | |
117 | tls = va_arg(ap, struct user_desc *); | |
118 | ctid = va_arg(ap, pid_t *); | |
119 | va_end(ap); | |
120 | ||
e822f505 | 121 | if (plibc_func == NULL) { |
616ed36a | 122 | plibc_func = dlsym(RTLD_NEXT, "clone"); |
e822f505 MD |
123 | if (plibc_func == NULL) { |
124 | fprintf(stderr, "libustfork: unable to find \"clone\" symbol.\n"); | |
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125 | return -1; |
126 | } | |
127 | } | |
128 | ||
e822f505 MD |
129 | if (flags & CLONE_VM) { |
130 | /* | |
131 | * Creating a thread, no need to intervene, just pass on | |
132 | * the arguments. | |
133 | */ | |
134 | retval = plibc_func(fn, child_stack, flags, arg, ptid, | |
135 | tls, ctid); | |
136 | } else { | |
137 | /* Creating a real process, we need to intervene. */ | |
29865d1c | 138 | struct ustfork_clone_info info = { .fn = fn, .arg = arg }; |
616ed36a | 139 | |
7f0aeeba | 140 | ust_before_fork(&info.sigset); |
e822f505 MD |
141 | retval = plibc_func(clone_fn, child_stack, flags, &info, |
142 | ptid, tls, ctid); | |
143 | /* The child doesn't get here. */ | |
7f0aeeba | 144 | ust_after_fork_parent(&info.sigset); |
616ed36a | 145 | } |
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146 | return retval; |
147 | } |