PostgreSQL Source Code  git master
signalfuncs.c File Reference
#include "postgres.h"
#include <signal.h>
#include "catalog/pg_authid.h"
#include "miscadmin.h"
#include "pgstat.h"
#include "postmaster/syslogger.h"
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "storage/procarray.h"
#include "utils/acl.h"
#include "utils/builtins.h"
Include dependency graph for signalfuncs.c:

Go to the source code of this file.

Macros

#define SIGNAL_BACKEND_SUCCESS   0
 
#define SIGNAL_BACKEND_ERROR   1
 
#define SIGNAL_BACKEND_NOPERMISSION   2
 
#define SIGNAL_BACKEND_NOSUPERUSER   3
 

Functions

static int pg_signal_backend (int pid, int sig)
 
Datum pg_cancel_backend (PG_FUNCTION_ARGS)
 
static bool pg_wait_until_termination (int pid, int64 timeout)
 
Datum pg_terminate_backend (PG_FUNCTION_ARGS)
 
Datum pg_reload_conf (PG_FUNCTION_ARGS)
 
Datum pg_rotate_logfile (PG_FUNCTION_ARGS)
 
Datum pg_rotate_logfile_v2 (PG_FUNCTION_ARGS)
 

Macro Definition Documentation

◆ SIGNAL_BACKEND_ERROR

#define SIGNAL_BACKEND_ERROR   1

Definition at line 45 of file signalfuncs.c.

Referenced by pg_signal_backend().

◆ SIGNAL_BACKEND_NOPERMISSION

#define SIGNAL_BACKEND_NOPERMISSION   2

Definition at line 46 of file signalfuncs.c.

Referenced by pg_cancel_backend(), pg_signal_backend(), and pg_terminate_backend().

◆ SIGNAL_BACKEND_NOSUPERUSER

#define SIGNAL_BACKEND_NOSUPERUSER   3

Definition at line 47 of file signalfuncs.c.

Referenced by pg_cancel_backend(), pg_signal_backend(), and pg_terminate_backend().

◆ SIGNAL_BACKEND_SUCCESS

#define SIGNAL_BACKEND_SUCCESS   0

Definition at line 44 of file signalfuncs.c.

Referenced by pg_cancel_backend(), pg_signal_backend(), and pg_terminate_backend().

Function Documentation

◆ pg_cancel_backend()

Datum pg_cancel_backend ( PG_FUNCTION_ARGS  )

Definition at line 112 of file signalfuncs.c.

References ereport, errcode(), errmsg(), ERROR, PG_GETARG_INT32, PG_RETURN_BOOL, pg_signal_backend(), SIGNAL_BACKEND_NOPERMISSION, SIGNAL_BACKEND_NOSUPERUSER, and SIGNAL_BACKEND_SUCCESS.

113 {
114  int r = pg_signal_backend(PG_GETARG_INT32(0), SIGINT);
115 
117  ereport(ERROR,
118  (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
119  errmsg("must be a superuser to cancel superuser query")));
120 
122  ereport(ERROR,
123  (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
124  errmsg("must be a member of the role whose query is being canceled or member of pg_signal_backend")));
125 
127 }
#define PG_GETARG_INT32(n)
Definition: fmgr.h:269
int errcode(int sqlerrcode)
Definition: elog.c:698
#define SIGNAL_BACKEND_SUCCESS
Definition: signalfuncs.c:44
static int pg_signal_backend(int pid, int sig)
Definition: signalfuncs.c:49
#define SIGNAL_BACKEND_NOSUPERUSER
Definition: signalfuncs.c:47
#define ERROR
Definition: elog.h:46
#define SIGNAL_BACKEND_NOPERMISSION
Definition: signalfuncs.c:46
#define PG_RETURN_BOOL(x)
Definition: fmgr.h:359
#define ereport(elevel,...)
Definition: elog.h:157
int errmsg(const char *fmt,...)
Definition: elog.c:909

◆ pg_reload_conf()

Datum pg_reload_conf ( PG_FUNCTION_ARGS  )

Definition at line 242 of file signalfuncs.c.

References ereport, errmsg(), kill, PG_RETURN_BOOL, PostmasterPid, SIGHUP, and WARNING.

243 {
244  if (kill(PostmasterPid, SIGHUP))
245  {
247  (errmsg("failed to send signal to postmaster: %m")));
248  PG_RETURN_BOOL(false);
249  }
250 
251  PG_RETURN_BOOL(true);
252 }
#define kill(pid, sig)
Definition: win32_port.h:454
#define SIGHUP
Definition: win32_port.h:159
pid_t PostmasterPid
Definition: globals.c:98
#define WARNING
Definition: elog.h:40
#define PG_RETURN_BOOL(x)
Definition: fmgr.h:359
#define ereport(elevel,...)
Definition: elog.h:157
int errmsg(const char *fmt,...)
Definition: elog.c:909

◆ pg_rotate_logfile()

Datum pg_rotate_logfile ( PG_FUNCTION_ARGS  )

Definition at line 261 of file signalfuncs.c.

References ereport, errcode(), errhint(), errmsg(), ERROR, Logging_collector, PG_RETURN_BOOL, PMSIGNAL_ROTATE_LOGFILE, SendPostmasterSignal(), superuser(), and WARNING.

262 {
263  if (!superuser())
264  ereport(ERROR,
265  (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
266  errmsg("must be superuser to rotate log files with adminpack 1.0"),
267  /* translator: %s is a SQL function name */
268  errhint("Consider using %s, which is part of core, instead.",
269  "pg_logfile_rotate()")));
270 
271  if (!Logging_collector)
272  {
274  (errmsg("rotation not possible because log collection not active")));
275  PG_RETURN_BOOL(false);
276  }
277 
279  PG_RETURN_BOOL(true);
280 }
int errhint(const char *fmt,...)
Definition: elog.c:1156
int errcode(int sqlerrcode)
Definition: elog.c:698
bool superuser(void)
Definition: superuser.c:46
bool Logging_collector
Definition: syslogger.c:70
#define ERROR
Definition: elog.h:46
#define WARNING
Definition: elog.h:40
#define PG_RETURN_BOOL(x)
Definition: fmgr.h:359
#define ereport(elevel,...)
Definition: elog.h:157
int errmsg(const char *fmt,...)
Definition: elog.c:909
void SendPostmasterSignal(PMSignalReason reason)
Definition: pmsignal.c:153

◆ pg_rotate_logfile_v2()

Datum pg_rotate_logfile_v2 ( PG_FUNCTION_ARGS  )

Definition at line 289 of file signalfuncs.c.

References ereport, errmsg(), Logging_collector, PG_RETURN_BOOL, PMSIGNAL_ROTATE_LOGFILE, SendPostmasterSignal(), and WARNING.

290 {
291  if (!Logging_collector)
292  {
294  (errmsg("rotation not possible because log collection not active")));
295  PG_RETURN_BOOL(false);
296  }
297 
299  PG_RETURN_BOOL(true);
300 }
bool Logging_collector
Definition: syslogger.c:70
#define WARNING
Definition: elog.h:40
#define PG_RETURN_BOOL(x)
Definition: fmgr.h:359
#define ereport(elevel,...)
Definition: elog.h:157
int errmsg(const char *fmt,...)
Definition: elog.c:909
void SendPostmasterSignal(PMSignalReason reason)
Definition: pmsignal.c:153

◆ pg_signal_backend()

static int pg_signal_backend ( int  pid,
int  sig 
)
static

Definition at line 49 of file signalfuncs.c.

References BackendPidGetProc(), ereport, errmsg(), GetUserId(), has_privs_of_role(), kill, PGPROC::roleId, SIGNAL_BACKEND_ERROR, SIGNAL_BACKEND_NOPERMISSION, SIGNAL_BACKEND_NOSUPERUSER, SIGNAL_BACKEND_SUCCESS, superuser(), superuser_arg(), and WARNING.

Referenced by pg_cancel_backend(), and pg_terminate_backend().

50 {
51  PGPROC *proc = BackendPidGetProc(pid);
52 
53  /*
54  * BackendPidGetProc returns NULL if the pid isn't valid; but by the time
55  * we reach kill(), a process for which we get a valid proc here might
56  * have terminated on its own. There's no way to acquire a lock on an
57  * arbitrary process to prevent that. But since so far all the callers of
58  * this mechanism involve some request for ending the process anyway, that
59  * it might end on its own first is not a problem.
60  */
61  if (proc == NULL)
62  {
63  /*
64  * This is just a warning so a loop-through-resultset will not abort
65  * if one backend terminated on its own during the run.
66  */
68  (errmsg("PID %d is not a PostgreSQL server process", pid)));
69  return SIGNAL_BACKEND_ERROR;
70  }
71 
72  /* Only allow superusers to signal superuser-owned backends. */
73  if (superuser_arg(proc->roleId) && !superuser())
75 
76  /* Users can signal backends they have role membership in. */
77  if (!has_privs_of_role(GetUserId(), proc->roleId) &&
78  !has_privs_of_role(GetUserId(), ROLE_PG_SIGNAL_BACKEND))
80 
81  /*
82  * Can the process we just validated above end, followed by the pid being
83  * recycled for a new process, before reaching here? Then we'd be trying
84  * to kill the wrong thing. Seems near impossible when sequential pid
85  * assignment and wraparound is used. Perhaps it could happen on a system
86  * where pid re-use is randomized. That race condition possibility seems
87  * too unlikely to worry about.
88  */
89 
90  /* If we have setsid(), signal the backend's whole process group */
91 #ifdef HAVE_SETSID
92  if (kill(-pid, sig))
93 #else
94  if (kill(pid, sig))
95 #endif
96  {
97  /* Again, just a warning to allow loops */
99  (errmsg("could not send signal to process %d: %m", pid)));
100  return SIGNAL_BACKEND_ERROR;
101  }
102  return SIGNAL_BACKEND_SUCCESS;
103 }
Oid GetUserId(void)
Definition: miscinit.c:478
PGPROC * BackendPidGetProc(int pid)
Definition: procarray.c:3133
bool has_privs_of_role(Oid member, Oid role)
Definition: acl.c:4843
Oid roleId
Definition: proc.h:155
bool superuser(void)
Definition: superuser.c:46
#define kill(pid, sig)
Definition: win32_port.h:454
#define SIGNAL_BACKEND_SUCCESS
Definition: signalfuncs.c:44
#define SIGNAL_BACKEND_NOSUPERUSER
Definition: signalfuncs.c:47
bool superuser_arg(Oid roleid)
Definition: superuser.c:56
#define SIGNAL_BACKEND_NOPERMISSION
Definition: signalfuncs.c:46
#define WARNING
Definition: elog.h:40
#define SIGNAL_BACKEND_ERROR
Definition: signalfuncs.c:45
static int sig
Definition: pg_ctl.c:84
#define ereport(elevel,...)
Definition: elog.h:157
int errmsg(const char *fmt,...)
Definition: elog.c:909
Definition: proc.h:121

◆ pg_terminate_backend()

Datum pg_terminate_backend ( PG_FUNCTION_ARGS  )

Definition at line 202 of file signalfuncs.c.

References ereport, errcode(), errmsg(), ERROR, PG_GETARG_INT32, PG_GETARG_INT64, PG_RETURN_BOOL, pg_signal_backend(), pg_wait_until_termination(), SIGNAL_BACKEND_NOPERMISSION, SIGNAL_BACKEND_NOSUPERUSER, and SIGNAL_BACKEND_SUCCESS.

203 {
204  int pid;
205  int r;
206  int timeout; /* milliseconds */
207 
208  pid = PG_GETARG_INT32(0);
209  timeout = PG_GETARG_INT64(1);
210 
211  if (timeout < 0)
212  ereport(ERROR,
213  (errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
214  errmsg("\"timeout\" must not be negative")));
215 
216  r = pg_signal_backend(pid, SIGTERM);
217 
219  ereport(ERROR,
220  (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
221  errmsg("must be a superuser to terminate superuser process")));
222 
224  ereport(ERROR,
225  (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
226  errmsg("must be a member of the role whose process is being terminated or member of pg_signal_backend")));
227 
228  /* Wait only on success and if actually requested */
229  if (r == SIGNAL_BACKEND_SUCCESS && timeout > 0)
231  else
233 }
#define PG_GETARG_INT32(n)
Definition: fmgr.h:269
int errcode(int sqlerrcode)
Definition: elog.c:698
#define SIGNAL_BACKEND_SUCCESS
Definition: signalfuncs.c:44
static int pg_signal_backend(int pid, int sig)
Definition: signalfuncs.c:49
#define SIGNAL_BACKEND_NOSUPERUSER
Definition: signalfuncs.c:47
#define ERROR
Definition: elog.h:46
#define SIGNAL_BACKEND_NOPERMISSION
Definition: signalfuncs.c:46
static bool pg_wait_until_termination(int pid, int64 timeout)
Definition: signalfuncs.c:134
#define PG_RETURN_BOOL(x)
Definition: fmgr.h:359
#define ereport(elevel,...)
Definition: elog.h:157
int errmsg(const char *fmt,...)
Definition: elog.c:909
#define PG_GETARG_INT64(n)
Definition: fmgr.h:283

◆ pg_wait_until_termination()

static bool pg_wait_until_termination ( int  pid,
int64  timeout 
)
static

Definition at line 134 of file signalfuncs.c.

References CHECK_FOR_INTERRUPTS, ereport, errcode(), errmsg(), errmsg_plural(), ERROR, kill, MyLatch, ResetLatch(), WAIT_EVENT_BACKEND_TERMINATION, WaitLatch(), WARNING, WL_EXIT_ON_PM_DEATH, WL_LATCH_SET, and WL_TIMEOUT.

Referenced by pg_terminate_backend().

135 {
136  /*
137  * Wait in steps of waittime milliseconds until this function exits or
138  * timeout.
139  */
140  int64 waittime = 100;
141 
142  /*
143  * Initially remaining time is the entire timeout specified by the user.
144  */
145  int64 remainingtime = timeout;
146 
147  /*
148  * Check existence of the backend. If the backend still exists, then wait
149  * for waittime milliseconds, again check for the existence. Repeat this
150  * until timeout or an error occurs or a pending interrupt such as query
151  * cancel gets processed.
152  */
153  do
154  {
155  if (remainingtime < waittime)
156  waittime = remainingtime;
157 
158  if (kill(pid, 0) == -1)
159  {
160  if (errno == ESRCH)
161  return true;
162  else
163  ereport(ERROR,
164  (errcode(ERRCODE_INTERNAL_ERROR),
165  errmsg("could not check the existence of the backend with PID %d: %m",
166  pid)));
167  }
168 
169  /* Process interrupts, if any, before waiting */
171 
172  (void) WaitLatch(MyLatch,
174  waittime,
176 
178 
179  remainingtime -= waittime;
180  } while (remainingtime > 0);
181 
183  (errmsg_plural("backend with PID %d did not terminate within %lld millisecond",
184  "backend with PID %d did not terminate within %lld milliseconds",
185  timeout,
186  pid, (long long int) timeout)));
187 
188  return false;
189 }
#define WL_TIMEOUT
Definition: latch.h:128
int errmsg_plural(const char *fmt_singular, const char *fmt_plural, unsigned long n,...)
Definition: elog.c:1019
int errcode(int sqlerrcode)
Definition: elog.c:698
#define kill(pid, sig)
Definition: win32_port.h:454
void ResetLatch(Latch *latch)
Definition: latch.c:660
int WaitLatch(Latch *latch, int wakeEvents, long timeout, uint32 wait_event_info)
Definition: latch.c:452
#define ERROR
Definition: elog.h:46
#define WARNING
Definition: elog.h:40
#define ereport(elevel,...)
Definition: elog.h:157
int errmsg(const char *fmt,...)
Definition: elog.c:909
struct Latch * MyLatch
Definition: globals.c:57
#define CHECK_FOR_INTERRUPTS()
Definition: miscadmin.h:120
#define WL_LATCH_SET
Definition: latch.h:125
#define WL_EXIT_ON_PM_DEATH
Definition: latch.h:130