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a334319f | 1 | /* Copyright (C) 2002, 2003 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 | |
15 | License along with the GNU C Library; if not, write to the Free | |
16 | Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA | |
17 | 02111-1307 USA. */ | |
18 | ||
19 | #include <sched.h> | |
20 | #include <signal.h> | |
21 | #include <sysdep.h> | |
22 | #include <unistd.h> | |
23 | #include <sys/wait.h> | |
24 | #include <bits/libc-lock.h> | |
25 | #include <kernel-features.h> | |
26 | ||
27 | /* We have to and actually can handle cancelable system(). The big | |
28 | problem: we have to kill the child process if necessary. To do | |
29 | this a cleanup handler has to be registered and is has to be able | |
30 | to find the PID of the child. The main problem is to reliable have | |
31 | the PID when needed. It is not necessary for the parent thread to | |
32 | return. It might still be in the kernel when the cancellation | |
33 | request comes. Therefore we have to use the clone() calls ability | |
34 | to have the kernel write the PID into the user-level variable. */ | |
35 | #if defined __ASSUME_CLONE_THREAD_FLAGS && !defined FORK | |
36 | # define FORK() \ | |
37 | INLINE_SYSCALL (clone, 3, CLONE_PARENT_SETTID | SIGCHLD, 0, &pid) | |
38 | #endif | |
39 | ||
9e9f1f15 | 40 | #ifdef _LIBC_REENTRANT |
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41 | static void cancel_handler (void *arg); |
42 | ||
9e9f1f15 | 43 | # define CLEANUP_HANDLER \ |
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44 | __libc_cleanup_region_start (1, cancel_handler, &pid) |
45 | ||
9e9f1f15 | 46 | # define CLEANUP_RESET \ |
7eecc0c2 | 47 | __libc_cleanup_region_end (0) |
9e9f1f15 | 48 | #endif |
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49 | |
50 | ||
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51 | /* Linux has waitpid(), so override the generic unix version. */ |
52 | #include <sysdeps/posix/system.c> | |
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53 | |
54 | ||
9e9f1f15 | 55 | #ifdef _LIBC_REENTRANT |
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56 | /* The cancellation handler. */ |
57 | static void | |
58 | cancel_handler (void *arg) | |
59 | { | |
60 | pid_t child = *(pid_t *) arg; | |
61 | ||
62 | INTERNAL_SYSCALL_DECL (err); | |
63 | INTERNAL_SYSCALL (kill, err, 2, child, SIGKILL); | |
64 | ||
65 | TEMP_FAILURE_RETRY (__waitpid (child, NULL, 0)); | |
66 | ||
67 | DO_LOCK (); | |
68 | ||
69 | if (SUB_REF () == 0) | |
70 | { | |
71 | (void) __sigaction (SIGQUIT, &quit, (struct sigaction *) NULL); | |
72 | (void) __sigaction (SIGINT, &intr, (struct sigaction *) NULL); | |
73 | } | |
74 | ||
75 | DO_UNLOCK (); | |
76 | } | |
9e9f1f15 | 77 | #endif |