1 /*- 2 * Copyright (c) 2006 Roman Divacky 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer 10 * in this position and unchanged. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 3. The name of the author may not be used to endorse or promote products 15 * derived from this software without specific prior written permission 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 27 */ 28 29 #include <sys/cdefs.h> 30 __FBSDID("$FreeBSD$"); 31 32 #include "opt_compat.h" 33 34 #include <sys/param.h> 35 #include <sys/systm.h> 36 #include <sys/imgact.h> 37 #include <sys/lock.h> 38 #include <sys/malloc.h> 39 #include <sys/mutex.h> 40 #include <sys/sx.h> 41 #include <sys/proc.h> 42 #include <sys/syscallsubr.h> 43 #include <sys/sysproto.h> 44 #include <sys/unistd.h> 45 46 #include <compat/linux/linux_emul.h> 47 #include <compat/linux/linux_futex.h> 48 49 #ifdef COMPAT_LINUX32 50 #include <machine/../linux32/linux.h> 51 #include <machine/../linux32/linux32_proto.h> 52 #else 53 #include <machine/../linux/linux.h> 54 #include <machine/../linux/linux_proto.h> 55 #endif 56 57 struct sx emul_shared_lock; 58 struct sx emul_lock; 59 60 /* this returns locked reference to the emuldata entry (if found) */ 61 struct linux_emuldata * 62 em_find(struct proc *p, int locked) 63 { 64 struct linux_emuldata *em; 65 66 if (locked == EMUL_UNLOCKED) 67 EMUL_LOCK(&emul_lock); 68 69 em = p->p_emuldata; 70 71 if (em == NULL && locked == EMUL_UNLOCKED) 72 EMUL_UNLOCK(&emul_lock); 73 74 return (em); 75 } 76 77 int 78 linux_proc_init(struct thread *td, pid_t child, int flags) 79 { 80 struct linux_emuldata *em, *p_em; 81 struct proc *p; 82 83 if (child != 0) { 84 /* non-exec call */ 85 em = malloc(sizeof *em, M_LINUX, M_WAITOK | M_ZERO); 86 em->pid = child; 87 if (flags & CLONE_VM) { 88 /* handled later in the code */ 89 } else { 90 struct linux_emuldata_shared *s; 91 92 s = malloc(sizeof *s, M_LINUX, M_WAITOK | M_ZERO); 93 em->shared = s; 94 s->refs = 1; 95 s->group_pid = child; 96 97 LIST_INIT(&s->threads); 98 } 99 p = pfind(child); 100 if (p == NULL) 101 panic("process not found in proc_init\n"); 102 p->p_emuldata = em; 103 PROC_UNLOCK(p); 104 } else { 105 /* lookup the old one */ 106 em = em_find(td->td_proc, EMUL_UNLOCKED); 107 KASSERT(em != NULL, ("proc_init: emuldata not found in exec case.\n")); 108 } 109 110 em->child_clear_tid = NULL; 111 em->child_set_tid = NULL; 112 113 /* 114 * allocate the shared struct only in clone()/fork cases 115 * in the case of clone() td = calling proc and child = pid of 116 * the newly created proc 117 */ 118 if (child != 0) { 119 if (flags & CLONE_VM) { 120 /* lookup the parent */ 121 p_em = em_find(td->td_proc, EMUL_LOCKED); 122 KASSERT(p_em != NULL, ("proc_init: parent emuldata not found for CLONE_VM\n")); 123 em->shared = p_em->shared; 124 em->shared->refs++; 125 } else { 126 /* handled earlier to avoid malloc(M_WAITOK) with rwlock held */ 127 } 128 } 129 130 131 if (child != 0) { 132 EMUL_SHARED_WLOCK(&emul_shared_lock); 133 LIST_INSERT_HEAD(&em->shared->threads, em, threads); 134 EMUL_SHARED_WUNLOCK(&emul_shared_lock); 135 136 p = pfind(child); 137 PROC_UNLOCK(p); 138 /* we might have a sleeping linux_schedtail */ 139 wakeup(&p->p_emuldata); 140 } else 141 EMUL_UNLOCK(&emul_lock); 142 143 return (0); 144 } 145 146 void 147 linux_proc_exit(void *arg __unused, struct proc *p) 148 { 149 struct linux_emuldata *em; 150 int error; 151 struct thread *td = FIRST_THREAD_IN_PROC(p); 152 int *child_clear_tid; 153 154 if (__predict_true(p->p_sysent != &elf_linux_sysvec)) 155 return; 156 157 /* find the emuldata */ 158 em = em_find(p, EMUL_UNLOCKED); 159 160 KASSERT(em != NULL, ("proc_exit: emuldata not found.\n")); 161 162 child_clear_tid = em->child_clear_tid; 163 164 EMUL_UNLOCK(&emul_lock); 165 166 EMUL_SHARED_WLOCK(&emul_shared_lock); 167 LIST_REMOVE(em, threads); 168 169 PROC_LOCK(p); 170 p->p_emuldata = NULL; 171 PROC_UNLOCK(p); 172 173 em->shared->refs--; 174 if (em->shared->refs == 0) 175 free(em->shared, M_LINUX); 176 EMUL_SHARED_WUNLOCK(&emul_shared_lock); 177 178 if (child_clear_tid != NULL) { 179 struct linux_sys_futex_args cup; 180 int null = 0; 181 182 error = copyout(&null, child_clear_tid, sizeof(null)); 183 if (error) 184 return; 185 186 /* futexes stuff */ 187 cup.uaddr = child_clear_tid; 188 cup.op = LINUX_FUTEX_WAKE; 189 cup.val = 0x7fffffff; /* Awake everyone */ 190 cup.timeout = NULL; 191 cup.uaddr2 = NULL; 192 cup.val3 = 0; 193 error = linux_sys_futex(FIRST_THREAD_IN_PROC(p), &cup); 194 /* 195 * this cannot happen at the moment and if this happens 196 * it probably mean there is a userspace bug 197 */ 198 if (error) 199 printf(LMSG("futex stuff in proc_exit failed.\n")); 200 } 201 202 /* clean the stuff up */ 203 free(em, M_LINUX); 204 } 205 206 /* 207 * This is used in a case of transition from FreeBSD binary execing to linux binary 208 * in this case we create linux emuldata proc entry with the pid of the currently running 209 * process. 210 */ 211 void linux_proc_exec(void *arg __unused, struct proc *p, struct image_params *imgp) 212 { 213 if (__predict_false(imgp->sysent == &elf_linux_sysvec 214 && p->p_sysent != &elf_linux_sysvec)) 215 linux_proc_init(FIRST_THREAD_IN_PROC(p), p->p_pid, 0); 216 if (__predict_false(imgp->sysent != &elf_linux_sysvec 217 && p->p_sysent == &elf_linux_sysvec)) { 218 struct linux_emuldata *em; 219 220 em = em_find(p, EMUL_UNLOCKED); 221 222 KASSERT(em != NULL, ("proc_exec: emuldata not found.\n")); 223 224 EMUL_UNLOCK(&emul_lock); 225 226 EMUL_SHARED_WLOCK(&emul_shared_lock); 227 LIST_REMOVE(em, threads); 228 229 PROC_LOCK(p); 230 p->p_emuldata = NULL; 231 PROC_UNLOCK(p); 232 233 em->shared->refs--; 234 if (em->shared->refs == 0) 235 FREE(em->shared, M_LINUX); 236 EMUL_SHARED_WUNLOCK(&emul_shared_lock); 237 238 FREE(em, M_LINUX); 239 } 240 } 241 242 extern int hz; /* in subr_param.c */ 243 244 void 245 linux_schedtail(void *arg __unused, struct proc *p) 246 { 247 struct linux_emuldata *em; 248 int error = 0; 249 int *child_set_tid; 250 251 if (p->p_sysent != &elf_linux_sysvec) 252 return; 253 254 retry: 255 /* find the emuldata */ 256 em = em_find(p, EMUL_UNLOCKED); 257 258 if (em == NULL) { 259 /* 260 * We might have been called before proc_init for this process so 261 * tsleep and be woken up by it. We use p->p_emuldata for this 262 */ 263 264 error = tsleep(&p->p_emuldata, PLOCK, "linux_schedtail", hz); 265 if (error == 0) 266 goto retry; 267 panic("no emuldata found for userreting process.\n"); 268 } 269 child_set_tid = em->child_set_tid; 270 EMUL_UNLOCK(&emul_lock); 271 272 if (child_set_tid != NULL) 273 error = copyout(&p->p_pid, (int *) child_set_tid, sizeof(p->p_pid)); 274 275 return; 276 } 277 278 int 279 linux_set_tid_address(struct thread *td, struct linux_set_tid_address_args *args) 280 { 281 struct linux_emuldata *em; 282 283 #ifdef DEBUG 284 if (ldebug(set_tid_address)) 285 printf(ARGS(set_tid_address, "%p"), args->tidptr); 286 #endif 287 288 /* find the emuldata */ 289 em = em_find(td->td_proc, EMUL_UNLOCKED); 290 291 KASSERT(em != NULL, ("set_tid_address: emuldata not found.\n")); 292 293 em->child_clear_tid = args->tidptr; 294 td->td_retval[0] = td->td_proc->p_pid; 295 296 EMUL_UNLOCK(&emul_lock); 297 return 0; 298 } 299