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688903eb | 1 | /* Copyright (C) 2002-2018 Free Software Foundation, Inc. |
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2 | This file is part of the GNU C Library. |
3 | ||
4 | The GNU C Library is free software; you can redistribute it and/or | |
5 | modify it under the terms of the GNU Lesser General Public | |
6 | License as published by the Free Software Foundation; either | |
7 | version 2.1 of the License, or (at your option) any later version. | |
8 | ||
9 | The GNU C Library is distributed in the hope that it will be useful, | |
10 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
11 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
12 | Lesser General Public License for more details. | |
13 | ||
14 | You should have received a copy of the GNU Lesser General Public | |
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15 | License along with the GNU C Library; if not, see |
16 | <http://www.gnu.org/licenses/>. */ | |
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17 | |
18 | #include <sched.h> | |
19 | #include <signal.h> | |
99c7f870 | 20 | #include <string.h> /* For the real memset prototype. */ |
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21 | #include <sysdep.h> |
22 | #include <unistd.h> | |
23 | #include <sys/wait.h> | |
ec999b8e | 24 | #include <libc-lock.h> |
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25 | |
26 | /* We have to and actually can handle cancelable system(). The big | |
27 | problem: we have to kill the child process if necessary. To do | |
28 | this a cleanup handler has to be registered and is has to be able | |
29 | to find the PID of the child. The main problem is to reliable have | |
30 | the PID when needed. It is not necessary for the parent thread to | |
31 | return. It might still be in the kernel when the cancellation | |
32 | request comes. Therefore we have to use the clone() calls ability | |
33 | to have the kernel write the PID into the user-level variable. */ | |
f2c05b9e | 34 | #ifndef FORK |
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35 | # define FORK() \ |
36 | INLINE_SYSCALL (clone, 3, CLONE_PARENT_SETTID | SIGCHLD, 0, &pid) | |
37 | #endif | |
38 | ||
9e9f1f15 | 39 | #ifdef _LIBC_REENTRANT |
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40 | static void cancel_handler (void *arg); |
41 | ||
9e9f1f15 | 42 | # define CLEANUP_HANDLER \ |
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43 | __libc_cleanup_region_start (1, cancel_handler, &pid) |
44 | ||
9e9f1f15 | 45 | # define CLEANUP_RESET \ |
7eecc0c2 | 46 | __libc_cleanup_region_end (0) |
9e9f1f15 | 47 | #endif |
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48 | |
49 | ||
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50 | /* Linux has waitpid(), so override the generic unix version. */ |
51 | #include <sysdeps/posix/system.c> | |
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52 | |
53 | ||
9e9f1f15 | 54 | #ifdef _LIBC_REENTRANT |
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55 | /* The cancellation handler. */ |
56 | static void | |
57 | cancel_handler (void *arg) | |
58 | { | |
59 | pid_t child = *(pid_t *) arg; | |
60 | ||
61 | INTERNAL_SYSCALL_DECL (err); | |
62 | INTERNAL_SYSCALL (kill, err, 2, child, SIGKILL); | |
63 | ||
64 | TEMP_FAILURE_RETRY (__waitpid (child, NULL, 0)); | |
65 | ||
66 | DO_LOCK (); | |
67 | ||
68 | if (SUB_REF () == 0) | |
69 | { | |
70 | (void) __sigaction (SIGQUIT, &quit, (struct sigaction *) NULL); | |
71 | (void) __sigaction (SIGINT, &intr, (struct sigaction *) NULL); | |
72 | } | |
73 | ||
74 | DO_UNLOCK (); | |
75 | } | |
9e9f1f15 | 76 | #endif |