Line data Source code
1 : /*--------------------------------------------------------------------
2 : * ps_status.c
3 : *
4 : * Routines to support changing the ps display of PostgreSQL backends
5 : * to contain some useful information. Mechanism differs wildly across
6 : * platforms.
7 : *
8 : * src/backend/utils/misc/ps_status.c
9 : *
10 : * Copyright (c) 2000-2017, PostgreSQL Global Development Group
11 : * various details abducted from various places
12 : *--------------------------------------------------------------------
13 : */
14 :
15 : #include "postgres.h"
16 :
17 : #include <unistd.h>
18 : #ifdef HAVE_SYS_PSTAT_H
19 : #include <sys/pstat.h> /* for HP-UX */
20 : #endif
21 : #ifdef HAVE_PS_STRINGS
22 : #include <machine/vmparam.h> /* for old BSD */
23 : #include <sys/exec.h>
24 : #endif
25 : #if defined(__darwin__)
26 : #include <crt_externs.h>
27 : #endif
28 :
29 : #include "libpq/libpq.h"
30 : #include "miscadmin.h"
31 : #include "utils/ps_status.h"
32 : #include "utils/guc.h"
33 :
34 : extern char **environ;
35 : bool update_process_title = true;
36 :
37 :
38 : /*
39 : * Alternative ways of updating ps display:
40 : *
41 : * PS_USE_SETPROCTITLE
42 : * use the function setproctitle(const char *, ...)
43 : * (newer BSD systems)
44 : * PS_USE_PSTAT
45 : * use the pstat(PSTAT_SETCMD, )
46 : * (HPUX)
47 : * PS_USE_PS_STRINGS
48 : * assign PS_STRINGS->ps_argvstr = "string"
49 : * (some BSD systems)
50 : * PS_USE_CHANGE_ARGV
51 : * assign argv[0] = "string"
52 : * (some other BSD systems)
53 : * PS_USE_CLOBBER_ARGV
54 : * write over the argv and environment area
55 : * (Linux and most SysV-like systems)
56 : * PS_USE_WIN32
57 : * push the string out as the name of a Windows event
58 : * PS_USE_NONE
59 : * don't update ps display
60 : * (This is the default, as it is safest.)
61 : */
62 : #if defined(HAVE_SETPROCTITLE)
63 : #define PS_USE_SETPROCTITLE
64 : #elif defined(HAVE_PSTAT) && defined(PSTAT_SETCMD)
65 : #define PS_USE_PSTAT
66 : #elif defined(HAVE_PS_STRINGS)
67 : #define PS_USE_PS_STRINGS
68 : #elif (defined(BSD) || defined(__hurd__)) && !defined(__darwin__)
69 : #define PS_USE_CHANGE_ARGV
70 : #elif defined(__linux__) || defined(_AIX) || defined(__sgi) || (defined(sun) && !defined(BSD)) || defined(__svr5__) || defined(__darwin__)
71 : #define PS_USE_CLOBBER_ARGV
72 : #elif defined(WIN32)
73 : #define PS_USE_WIN32
74 : #else
75 : #define PS_USE_NONE
76 : #endif
77 :
78 :
79 : /* Different systems want the buffer padded differently */
80 : #if defined(_AIX) || defined(__linux__) || defined(__darwin__)
81 : #define PS_PADDING '\0'
82 : #else
83 : #define PS_PADDING ' '
84 : #endif
85 :
86 :
87 : #ifndef PS_USE_CLOBBER_ARGV
88 : /* all but one option need a buffer to write their ps line in */
89 : #define PS_BUFFER_SIZE 256
90 : static char ps_buffer[PS_BUFFER_SIZE];
91 : static const size_t ps_buffer_size = PS_BUFFER_SIZE;
92 : #else /* PS_USE_CLOBBER_ARGV */
93 : static char *ps_buffer; /* will point to argv area */
94 : static size_t ps_buffer_size; /* space determined at run time */
95 : static size_t last_status_len; /* use to minimize length of clobber */
96 : #endif /* PS_USE_CLOBBER_ARGV */
97 :
98 : static size_t ps_buffer_cur_len; /* nominal strlen(ps_buffer) */
99 :
100 : static size_t ps_buffer_fixed_size; /* size of the constant prefix */
101 :
102 : /* save the original argv[] location here */
103 : static int save_argc;
104 : static char **save_argv;
105 :
106 :
107 : /*
108 : * Call this early in startup to save the original argc/argv values.
109 : * If needed, we make a copy of the original argv[] array to preserve it
110 : * from being clobbered by subsequent ps_display actions.
111 : *
112 : * (The original argv[] will not be overwritten by this routine, but may be
113 : * overwritten during init_ps_display. Also, the physical location of the
114 : * environment strings may be moved, so this should be called before any code
115 : * that might try to hang onto a getenv() result.)
116 : *
117 : * Note that in case of failure this cannot call elog() as that is not
118 : * initialized yet. We rely on write_stderr() instead.
119 : */
120 : char **
121 6 : save_ps_display_args(int argc, char **argv)
122 : {
123 6 : save_argc = argc;
124 6 : save_argv = argv;
125 :
126 : #if defined(PS_USE_CLOBBER_ARGV)
127 :
128 : /*
129 : * If we're going to overwrite the argv area, count the available space.
130 : * Also move the environment to make additional room.
131 : */
132 : {
133 6 : char *end_of_area = NULL;
134 : char **new_environ;
135 : int i;
136 :
137 : /*
138 : * check for contiguous argv strings
139 : */
140 50 : for (i = 0; i < argc; i++)
141 : {
142 44 : if (i == 0 || end_of_area + 1 == argv[i])
143 44 : end_of_area = argv[i] + strlen(argv[i]);
144 : }
145 :
146 6 : if (end_of_area == NULL) /* probably can't happen? */
147 : {
148 0 : ps_buffer = NULL;
149 0 : ps_buffer_size = 0;
150 0 : return argv;
151 : }
152 :
153 : /*
154 : * check for contiguous environ strings following argv
155 : */
156 207 : for (i = 0; environ[i] != NULL; i++)
157 : {
158 201 : if (end_of_area + 1 == environ[i])
159 201 : end_of_area = environ[i] + strlen(environ[i]);
160 : }
161 :
162 6 : ps_buffer = argv[0];
163 6 : last_status_len = ps_buffer_size = end_of_area - argv[0];
164 :
165 : /*
166 : * move the environment out of the way
167 : */
168 6 : new_environ = (char **) malloc((i + 1) * sizeof(char *));
169 6 : if (!new_environ)
170 : {
171 0 : write_stderr("out of memory\n");
172 0 : exit(1);
173 : }
174 207 : for (i = 0; environ[i] != NULL; i++)
175 : {
176 201 : new_environ[i] = strdup(environ[i]);
177 201 : if (!new_environ[i])
178 : {
179 0 : write_stderr("out of memory\n");
180 0 : exit(1);
181 : }
182 : }
183 6 : new_environ[i] = NULL;
184 6 : environ = new_environ;
185 : }
186 : #endif /* PS_USE_CLOBBER_ARGV */
187 :
188 : #if defined(PS_USE_CHANGE_ARGV) || defined(PS_USE_CLOBBER_ARGV)
189 :
190 : /*
191 : * If we're going to change the original argv[] then make a copy for
192 : * argument parsing purposes.
193 : *
194 : * (NB: do NOT think to remove the copying of argv[], even though
195 : * postmaster.c finishes looking at argv[] long before we ever consider
196 : * changing the ps display. On some platforms, getopt() keeps pointers
197 : * into the argv array, and will get horribly confused when it is
198 : * re-called to analyze a subprocess' argument string if the argv storage
199 : * has been clobbered meanwhile. Other platforms have other dependencies
200 : * on argv[].
201 : */
202 : {
203 : char **new_argv;
204 : int i;
205 :
206 6 : new_argv = (char **) malloc((argc + 1) * sizeof(char *));
207 6 : if (!new_argv)
208 : {
209 0 : write_stderr("out of memory\n");
210 0 : exit(1);
211 : }
212 50 : for (i = 0; i < argc; i++)
213 : {
214 44 : new_argv[i] = strdup(argv[i]);
215 44 : if (!new_argv[i])
216 : {
217 0 : write_stderr("out of memory\n");
218 0 : exit(1);
219 : }
220 : }
221 6 : new_argv[argc] = NULL;
222 :
223 : #if defined(__darwin__)
224 :
225 : /*
226 : * macOS (and perhaps other NeXT-derived platforms?) has a static copy
227 : * of the argv pointer, which we may fix like so:
228 : */
229 : *_NSGetArgv() = new_argv;
230 : #endif
231 :
232 6 : argv = new_argv;
233 : }
234 : #endif /* PS_USE_CHANGE_ARGV or PS_USE_CLOBBER_ARGV */
235 :
236 6 : return argv;
237 : }
238 :
239 : /*
240 : * Call this once during subprocess startup to set the identification
241 : * values. At this point, the original argv[] array may be overwritten.
242 : */
243 : void
244 341 : init_ps_display(const char *username, const char *dbname,
245 : const char *host_info, const char *initial_str)
246 : {
247 341 : Assert(username);
248 341 : Assert(dbname);
249 341 : Assert(host_info);
250 :
251 : #ifndef PS_USE_NONE
252 : /* no ps display for stand-alone backend */
253 341 : if (!IsUnderPostmaster)
254 0 : return;
255 :
256 : /* no ps display if you didn't call save_ps_display_args() */
257 341 : if (!save_argv)
258 0 : return;
259 :
260 : #ifdef PS_USE_CLOBBER_ARGV
261 : /* If ps_buffer is a pointer, it might still be null */
262 341 : if (!ps_buffer)
263 0 : return;
264 : #endif
265 :
266 : /*
267 : * Overwrite argv[] to point at appropriate space, if needed
268 : */
269 :
270 : #ifdef PS_USE_CHANGE_ARGV
271 : save_argv[0] = ps_buffer;
272 : save_argv[1] = NULL;
273 : #endif /* PS_USE_CHANGE_ARGV */
274 :
275 : #ifdef PS_USE_CLOBBER_ARGV
276 : {
277 : int i;
278 :
279 : /* make extra argv slots point at end_of_area (a NUL) */
280 2728 : for (i = 1; i < save_argc; i++)
281 2387 : save_argv[i] = ps_buffer + ps_buffer_size;
282 : }
283 : #endif /* PS_USE_CLOBBER_ARGV */
284 :
285 : /*
286 : * Make fixed prefix of ps display.
287 : */
288 :
289 : #ifdef PS_USE_SETPROCTITLE
290 :
291 : /*
292 : * apparently setproctitle() already adds a `progname:' prefix to the ps
293 : * line
294 : */
295 : #define PROGRAM_NAME_PREFIX ""
296 : #else
297 : #define PROGRAM_NAME_PREFIX "postgres: "
298 : #endif
299 :
300 341 : if (*cluster_name == '\0')
301 : {
302 341 : snprintf(ps_buffer, ps_buffer_size,
303 : PROGRAM_NAME_PREFIX "%s %s %s ",
304 : username, dbname, host_info);
305 : }
306 : else
307 : {
308 0 : snprintf(ps_buffer, ps_buffer_size,
309 : PROGRAM_NAME_PREFIX "%s: %s %s %s ",
310 : cluster_name, username, dbname, host_info);
311 : }
312 :
313 341 : ps_buffer_cur_len = ps_buffer_fixed_size = strlen(ps_buffer);
314 :
315 341 : set_ps_display(initial_str, true);
316 : #endif /* not PS_USE_NONE */
317 : }
318 :
319 :
320 :
321 : /*
322 : * Call this to update the ps status display to a fixed prefix plus an
323 : * indication of what you're currently doing passed in the argument.
324 : */
325 : void
326 55839 : set_ps_display(const char *activity, bool force)
327 : {
328 : #ifndef PS_USE_NONE
329 : /* update_process_title=off disables updates, unless force = true */
330 55839 : if (!force && !update_process_title)
331 0 : return;
332 :
333 : /* no ps display for stand-alone backend */
334 55839 : if (!IsUnderPostmaster)
335 1549 : return;
336 :
337 : #ifdef PS_USE_CLOBBER_ARGV
338 : /* If ps_buffer is a pointer, it might still be null */
339 54290 : if (!ps_buffer)
340 0 : return;
341 : #endif
342 :
343 : /* Update ps_buffer to contain both fixed part and activity */
344 54290 : strlcpy(ps_buffer + ps_buffer_fixed_size, activity,
345 : ps_buffer_size - ps_buffer_fixed_size);
346 54290 : ps_buffer_cur_len = strlen(ps_buffer);
347 :
348 : /* Transmit new setting to kernel, if necessary */
349 :
350 : #ifdef PS_USE_SETPROCTITLE
351 : setproctitle("%s", ps_buffer);
352 : #endif
353 :
354 : #ifdef PS_USE_PSTAT
355 : {
356 : union pstun pst;
357 :
358 : pst.pst_command = ps_buffer;
359 : pstat(PSTAT_SETCMD, pst, ps_buffer_cur_len, 0, 0);
360 : }
361 : #endif /* PS_USE_PSTAT */
362 :
363 : #ifdef PS_USE_PS_STRINGS
364 : PS_STRINGS->ps_nargvstr = 1;
365 : PS_STRINGS->ps_argvstr = ps_buffer;
366 : #endif /* PS_USE_PS_STRINGS */
367 :
368 : #ifdef PS_USE_CLOBBER_ARGV
369 : /* pad unused memory; need only clobber remainder of old status string */
370 54290 : if (last_status_len > ps_buffer_cur_len)
371 27203 : MemSet(ps_buffer + ps_buffer_cur_len, PS_PADDING,
372 : last_status_len - ps_buffer_cur_len);
373 54290 : last_status_len = ps_buffer_cur_len;
374 : #endif /* PS_USE_CLOBBER_ARGV */
375 :
376 : #ifdef PS_USE_WIN32
377 : {
378 : /*
379 : * Win32 does not support showing any changed arguments. To make it at
380 : * all possible to track which backend is doing what, we create a
381 : * named object that can be viewed with for example Process Explorer.
382 : */
383 : static HANDLE ident_handle = INVALID_HANDLE_VALUE;
384 : char name[PS_BUFFER_SIZE + 32];
385 :
386 : if (ident_handle != INVALID_HANDLE_VALUE)
387 : CloseHandle(ident_handle);
388 :
389 : sprintf(name, "pgident(%d): %s", MyProcPid, ps_buffer);
390 :
391 : ident_handle = CreateEvent(NULL, TRUE, FALSE, name);
392 : }
393 : #endif /* PS_USE_WIN32 */
394 : #endif /* not PS_USE_NONE */
395 : }
396 :
397 :
398 : /*
399 : * Returns what's currently in the ps display, in case someone needs
400 : * it. Note that only the activity part is returned. On some platforms
401 : * the string will not be null-terminated, so return the effective
402 : * length into *displen.
403 : */
404 : const char *
405 14 : get_ps_display(int *displen)
406 : {
407 : #ifdef PS_USE_CLOBBER_ARGV
408 : /* If ps_buffer is a pointer, it might still be null */
409 14 : if (!ps_buffer)
410 : {
411 0 : *displen = 0;
412 0 : return "";
413 : }
414 : #endif
415 :
416 14 : *displen = (int) (ps_buffer_cur_len - ps_buffer_fixed_size);
417 :
418 14 : return ps_buffer + ps_buffer_fixed_size;
419 : }
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