1 /*
2  * Based on src/backend/utils/misc/pg_status.c from
3  * PostgreSQL Database Management System
4  *
5  * Portions Copyright (c) 1996-2001, The PostgreSQL Global Development Group
6  *
7  * Portions Copyright (c) 1994, The Regents of the University of California
8  *
9  * Permission to use, copy, modify, and distribute this software and its
10  * documentation for any purpose, without fee, and without a written agreement
11  * is hereby granted, provided that the above copyright notice and this
12  * paragraph and the following two paragraphs appear in all copies.
13  *
14  * IN NO EVENT SHALL THE UNIVERSITY OF CALIFORNIA BE LIABLE TO ANY PARTY FOR
15  * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, INCLUDING
16  * LOST PROFITS, ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS
17  * DOCUMENTATION, EVEN IF THE UNIVERSITY OF CALIFORNIA HAS BEEN ADVISED OF THE
18  * POSSIBILITY OF SUCH DAMAGE.
19  *
20  * THE UNIVERSITY OF CALIFORNIA SPECIFICALLY DISCLAIMS ANY WARRANTIES,
21  * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
22  * AND FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
23  * ON AN "AS IS" BASIS, AND THE UNIVERSITY OF CALIFORNIA HAS NO OBLIGATIONS TO
24  * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
25  */
26 
27 /*--------------------------------------------------------------------
28  * ps_status.c
29  *
30  * Routines to support changing the ps display of PostgreSQL backends
31  * to contain some useful information. Mechanism differs wildly across
32  * platforms.
33  *
34  * $Header: /var/cvs/openssh/openbsd-compat/setproctitle.c,v 1.5 2003/01/20 02:15:11 djm Exp $
35  *
36  * Copyright 2000 by PostgreSQL Global Development Group
37  * various details abducted from various places
38  *--------------------------------------------------------------------
39  */
40 
41 #include "includes.h"
42 
43 #ifndef HAVE_SETPROCTITLE
44 
45 #include <unistd.h>
46 #ifdef HAVE_SYS_PSTAT_H
47 #include <sys/pstat.h>		/* for HP-UX */
48 #endif
49 #ifdef HAVE_PS_STRINGS
50 #include <machine/vmparam.h>	/* for old BSD */
51 #include <sys/exec.h>
52 #endif
53 
54 /*------
55  * Alternative ways of updating ps display:
56  *
57  * SETPROCTITLE_STRATEGY == PS_USE_PSTAT
58  *	   use the pstat(PSTAT_SETCMD, )
59  *	   (HPUX)
60  * SETPROCTITLE_STRATEGY == PS_USE_PS_STRINGS
61  *	   assign PS_STRINGS->ps_argvstr = "string"
62  *	   (some BSD systems)
63  * SETPROCTITLE_STRATEGY == PS_USE_CHANGE_ARGV
64  *	   assign argv[0] = "string"
65  *	   (some other BSD systems)
66  * SETPROCTITLE_STRATEGY == PS_USE_CLOBBER_ARGV
67  *	   write over the argv and environment area
68  *	   (most SysV-like systems)
69  * SETPROCTITLE_STRATEGY == PS_USE_NONE
70  *	   don't update ps display
71  *	   (This is the default, as it is safest.)
72  */
73 
74 #define PS_USE_NONE			0
75 #define PS_USE_PSTAT			1
76 #define PS_USE_PS_STRINGS		2
77 #define PS_USE_CHANGE_ARGV		3
78 #define PS_USE_CLOBBER_ARGV		4
79 
80 #ifndef SETPROCTITLE_STRATEGY
81 # define SETPROCTITLE_STRATEGY	PS_USE_NONE
82 #endif
83 
84 #ifndef SETPROCTITLE_PS_PADDING
85 # define SETPROCTITLE_PS_PADDING	' '
86 #endif
87 #endif /* HAVE_SETPROCTITLE */
88 
89 extern char **environ;
90 
91 /*
92  * argv clobbering uses existing argv space, all other methods need a buffer
93  */
94 #if SETPROCTITLE_STRATEGY != PS_USE_CLOBBER_ARGV
95 static char ps_buffer[256];
96 static const size_t ps_buffer_size = sizeof(ps_buffer);
97 #else
98 static char *ps_buffer;			/* will point to argv area */
99 static size_t ps_buffer_size;		/* space determined at run time */
100 #endif
101 
102 /* save the original argv[] location here */
103 static int	save_argc;
104 static char **save_argv;
105 
106 extern char *__progname;
107 
108 #ifndef HAVE_SETPROCTITLE
109 /*
110  * Call this to update the ps status display to a fixed prefix plus an
111  * indication of what you're currently doing passed in the argument.
112  */
113 void
114 setproctitle(const char *fmt, ...)
115 {
116 #if SETPROCTITLE_STRATEGY == PS_USE_PSTAT
117 	union pstun pst;
118 #endif
119 #if SETPROCTITLE_STRATEGY != PS_USE_NONE
120 	ssize_t used;
121 	va_list ap;
122 
123 	/* no ps display if you didn't call save_ps_display_args() */
124 	if (save_argv == NULL)
125 		return;
126 #if SETPROCTITLE_STRATEGY == PS_USE_CLOBBER_ARGV
127 	/* If ps_buffer is a pointer, it might still be null */
128 	if (ps_buffer == NULL)
129 		return;
130 #endif /* PS_USE_CLOBBER_ARGV */
131 
132 	/*
133 	 * Overwrite argv[] to point at appropriate space, if needed
134 	 */
135 #if SETPROCTITLE_STRATEGY == PS_USE_CHANGE_ARGV
136 	save_argv[0] = ps_buffer;
137 	save_argv[1] = NULL;
138 #endif /* PS_USE_CHANGE_ARGV */
139 
140 #if SETPROCTITLE_STRATEGY == PS_USE_CLOBBER_ARGV
141 	save_argv[1] = NULL;
142 #endif /* PS_USE_CLOBBER_ARGV */
143 
144 	/*
145 	 * Make fixed prefix of ps display.
146 	 */
147 
148 	va_start(ap, fmt);
149 	if (fmt == NULL)
150 		snprintf(ps_buffer, ps_buffer_size, "%s", __progname);
151 	else {
152 		used = snprintf(ps_buffer, ps_buffer_size, "%s: ", __progname);
153 		if (used == -1 || used >= ps_buffer_size)
154 			used = ps_buffer_size;
155 		vsnprintf(ps_buffer + used, ps_buffer_size - used, fmt, ap);
156 	}
157 	va_end(ap);
158 
159 #if SETPROCTITLE_STRATEGY == PS_USE_PSTAT
160 	pst.pst_command = ps_buffer;
161 	pstat(PSTAT_SETCMD, pst, strlen(ps_buffer), 0, 0);
162 #endif   /* PS_USE_PSTAT */
163 
164 #if SETPROCTITLE_STRATEGY == PS_USE_PS_STRINGS
165 	PS_STRINGS->ps_nargvstr = 1;
166 	PS_STRINGS->ps_argvstr = ps_buffer;
167 #endif   /* PS_USE_PS_STRINGS */
168 
169 #if SETPROCTITLE_STRATEGY == PS_USE_CLOBBER_ARGV
170 	/* pad unused memory */
171 	used = strlen(ps_buffer);
172 	memset(ps_buffer + used, SETPROCTITLE_PS_PADDING,
173 	    ps_buffer_size - used);
174 #endif   /* PS_USE_CLOBBER_ARGV */
175 
176 #endif /* PS_USE_NONE */
177 }
178 
179 #endif /* HAVE_SETPROCTITLE */
180 
181 /*
182  * Call this early in startup to save the original argc/argv values.
183  *
184  * argv[] will not be overwritten by this routine, but may be overwritten
185  * during setproctitle. Also, the physical location of the environment
186  * strings may be moved, so this should be called before any code that
187  * might try to hang onto a getenv() result.
188  */
189 void
190 compat_init_setproctitle(int argc, char *argv[])
191 {
192 #if SETPROCTITLE_STRATEGY == PS_USE_CLOBBER_ARGV
193 	char *end_of_area = NULL;
194 	char **new_environ;
195 	int i;
196 #endif
197 
198 	save_argc = argc;
199 	save_argv = argv;
200 
201 #if SETPROCTITLE_STRATEGY == PS_USE_CLOBBER_ARGV
202 	/*
203 	 * If we're going to overwrite the argv area, count the available
204 	 * space.  Also move the environment to make additional room.
205 	 */
206 
207 	/*
208 	 * check for contiguous argv strings
209 	 */
210 	for (i = 0; i < argc; i++) {
211 		if (i == 0 || end_of_area + 1 == argv[i])
212 			end_of_area = argv[i] + strlen(argv[i]);
213 	}
214 
215 	/* probably can't happen? */
216 	if (end_of_area == NULL) {
217 		ps_buffer = NULL;
218 		ps_buffer_size = 0;
219 		return;
220 	}
221 
222 	/*
223 	 * check for contiguous environ strings following argv
224 	 */
225 	for (i = 0; environ[i] != NULL; i++) {
226 		if (end_of_area + 1 == environ[i])
227 			end_of_area = environ[i] + strlen(environ[i]);
228 	}
229 
230 	ps_buffer = argv[0];
231 	ps_buffer_size = end_of_area - argv[0] - 1;
232 
233 	/*
234 	 * Duplicate and move the environment out of the way
235 	 */
236 	new_environ = malloc(sizeof(char *) * (i + 1));
237 	for (i = 0; environ[i] != NULL; i++)
238 		new_environ[i] = strdup(environ[i]);
239 	new_environ[i] = NULL;
240 	environ = new_environ;
241 #endif /* PS_USE_CLOBBER_ARGV */
242 }
243 
244