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本帖最后由 wait_rabbit 于 2017-02-04 19:19 编辑
你设置了 random pid ？
241，242行
话说引用的代码里边怎么加粗，标红？
- 186 static int randompid = 0;
- 187
- 188 static int
- 189 sysctl_kern_randompid(SYSCTL_HANDLER_ARGS)
- 190 {
- 191 int error, pid;
- 192
- 193 error = sysctl_wire_old_buffer(req, sizeof(int));
- 194 if (error != 0)
- 195 return(error);
- 196 sx_xlock(&allproc_lock);
- 197 pid = randompid;
- 198 error = sysctl_handle_int(oidp, &pid, 0, req);
- 199 if (error == 0 && req->newptr != NULL) {
- 200 if (pid < 0 || pid > pid_max - 100) /* out of range */
- 201 pid = pid_max - 100;
- 202 else if (pid < 2) /* NOP */
- 203 pid = 0;
- 204 else if (pid < 100) /* Make it reasonable */
- 205 pid = 100;
- 206 randompid = pid;
- 207 }
- 208 sx_xunlock(&allproc_lock);
- 209 return (error);
- 210 }
- 211
- 212 SYSCTL_PROC(_kern, OID_AUTO, randompid, CTLTYPE_INT|CTLFLAG_RW,
- 213 0, 0, sysctl_kern_randompid, "I", "Random PID modulus");
- 214
- 215 static int
- 216 fork_findpid(int flags)
- 217 {
- 218 struct proc *p;
- 219 int trypid;
- 220 static int pidchecked = 0;
- 221
- 222 /*
- 223 * Requires allproc_lock in order to iterate over the list
- 224 * of processes, and proctree_lock to access p_pgrp.
- 225 */
- 226 sx_assert(&allproc_lock, SX_LOCKED);
- 227 sx_assert(&proctree_lock, SX_LOCKED);
- 228
- 229 /*
- 230 * Find an unused process ID. We remember a range of unused IDs
- 231 * ready to use (from lastpid+1 through pidchecked-1).
- 232 *
- 233 * If RFHIGHPID is set (used during system boot), do not allocate
- 234 * low-numbered pids.
- 235 */
- 236 trypid = lastpid + 1;
- 237 if (flags & RFHIGHPID) {
- 238 if (trypid < 10)
- 239 trypid = 10;
- 240 } else {
- 241 if (randompid)
- 242 trypid += arc4random() % randompid;
- 243 }
- 244 retry:
- 245 /*
- 246 * If the process ID prototype has wrapped around,
- 247 * restart somewhat above 0, as the low-numbered procs
- 248 * tend to include daemons that don't exit.
- 249 */
- 250 if (trypid >= pid_max) {
- 251 trypid = trypid % pid_max;
- 252 if (trypid < 100)
- 253 trypid += 100;
- 254 pidchecked = 0;
- 255 }
- 256 if (trypid >= pidchecked) {
- 257 int doingzomb = 0;
- 258
- 259 pidchecked = PID_MAX;
- 260 /*
- 261 * Scan the active and zombie procs to check whether this pid
- 262 * is in use. Remember the lowest pid that's greater
- 263 * than trypid, so we can avoid checking for a while.
- 264 */
- 265 p = LIST_FIRST(&allproc);
- 266 again:
- 267 for (; p != NULL; p = LIST_NEXT(p, p_list)) {
- 268 while (p->p_pid == trypid ||
- 269 (p->p_pgrp != NULL &&
- 270 (p->p_pgrp->pg_id == trypid ||
- 271 (p->p_session != NULL &&
- 272 p->p_session->s_sid == trypid)))) {
- 273 trypid++;
- 274 if (trypid >= pidchecked)
- 275 goto retry;
- 276 }
- 277 if (p->p_pid > trypid && pidchecked > p->p_pid)
- 278 pidchecked = p->p_pid;
- 279 if (p->p_pgrp != NULL) {
- 280 if (p->p_pgrp->pg_id > trypid &&
- 281 pidchecked > p->p_pgrp->pg_id)
- 282 pidchecked = p->p_pgrp->pg_id;
- 283 if (p->p_session != NULL &&
- 284 p->p_session->s_sid > trypid &&
- 285 pidchecked > p->p_session->s_sid)
- 286 pidchecked = p->p_session->s_sid;
- 287 }
- 288 }
- 289 if (!doingzomb) {
- 290 doingzomb = 1;
- 291 p = LIST_FIRST(&zombproc);
- 292 goto again;
- 293 }
- 294
- 296 /*
- 297 * RFHIGHPID does not mess with the lastpid counter during boot.
- 298 */
- 299 if (flags & RFHIGHPID)
- 300 pidchecked = 0;
- 301 else
- 302 lastpid = trypid;
- 303
- 304 return (trypid);
- 305 }
- 306
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发表于 2017-02-02 10:25
发表于 2017-02-04 12:39
