setproctitle.c revision 53297 
1/*
2 * Copyright (c) 1995 Peter Wemm <peter@freebsd.org>
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, is permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice immediately at the beginning of the file, without modification,
10 *    this list of conditions, and the following disclaimer.
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. Absolutely no warranty of function or purpose is made by the author
15 *    Peter Wemm.
16 *
17 * $FreeBSD: head/lib/libc/gen/setproctitle.c 53297 1999-11-17 21:12:17Z brian $
18 */
19
20#include <sys/types.h>
21#include <sys/param.h>
22#include <sys/exec.h>
23#include <sys/sysctl.h>
24
25#include <vm/vm.h>
26#include <vm/vm_param.h>
27#include <vm/pmap.h>
28
29#include <stdio.h>
30#include <string.h>
31#include <stdlib.h>
32#include <unistd.h>
33
34/*
35 * Older FreeBSD 2.0, 2.1 and 2.2 had different ps_strings structures and
36 * in different locations.
37 * 1: old_ps_strings at the very top of the stack.
38 * 2: old_ps_strings at SPARE_USRSPACE below the top of the stack.
39 * 3: ps_strings at the very top of the stack.
40 * This attempts to support a kernel built in the #2 and #3 era.
41 */
42
43struct old_ps_strings {
44	char	*old_ps_argvstr;
45	int	old_ps_nargvstr;
46	char	*old_ps_envstr;
47	int	old_ps_nenvstr;
48};
49#define	OLD_PS_STRINGS ((struct old_ps_strings *) \
50	(USRSTACK - SPARE_USRSPACE - sizeof(struct old_ps_strings)))
51
52#if defined(__STDC__)		/* from other parts of sendmail */
53#include <stdarg.h>
54#else
55#include <varargs.h>
56#endif
57
58
59#define SPT_BUFSIZE 2048	/* from other parts of sendmail */
60extern char * __progname;	/* is this defined in a .h anywhere? */
61
62void
63#if defined(__STDC__)
64setproctitle(const char *fmt, ...)
65#else
66setproctitle(fmt, va_alist)
67	const char *fmt;
68	va_dcl
69#endif
70{
71	static struct ps_strings *ps_strings;
72	static char buf[SPT_BUFSIZE];
73	static char obuf[SPT_BUFSIZE];
74	static char **oargv, *kbuf;
75	static int oargc = -1;
76	static char *nargv[2] = { buf, NULL };
77	char **nargvp;
78	int nargc;
79	va_list ap;
80	size_t len;
81	unsigned long ul_ps_strings;
82	int oid[4];
83
84#if defined(__STDC__)
85	va_start(ap, fmt);
86#else
87	va_start(ap);
88#endif
89
90	if (fmt) {
91		buf[sizeof(buf) - 1] = '\0';
92
93		/* print program name heading for grep */
94		(void) snprintf(buf, sizeof(buf), "%s: ", __progname);
95
96		/*
97		 * can't use return from sprintf, as that is the count of how
98		 * much it wanted to write, not how much it actually did.
99		 */
100
101		len = strlen(buf);
102
103		/* print the argument string */
104		(void) vsnprintf(buf + len, sizeof(buf) - len, fmt, ap);
105
106		nargvp = nargv;
107		nargc = 1;
108		kbuf = buf;
109	} else if (*obuf != '\0') {
110  		/* Idea from NetBSD - reset the title on fmt == NULL */
111		nargvp = oargv;
112		nargc = oargc;
113		kbuf = obuf;
114	} else
115		/* Nothing to restore */
116		return;
117
118	va_end(ap);
119
120	/* Set the title into the kernel cached command line */
121	oid[0] = CTL_KERN;
122	oid[1] = KERN_PROC;
123	oid[2] = KERN_PROC_ARGS;
124	oid[3] = getpid();
125	sysctl(oid, 4, 0, 0, kbuf, strlen(kbuf) + 1);
126
127	if (ps_strings == NULL) {
128		len = sizeof(ul_ps_strings);
129		if (sysctlbyname("kern.ps_strings", &ul_ps_strings, &len, NULL,
130		    0) == -1)
131			ul_ps_strings = PS_STRINGS;
132		ps_strings = (struct ps_strings *)ul_ps_strings;
133	}
134
135	/* PS_STRINGS points to zeroed memory on a style #2 kernel */
136	if (ps_strings->ps_argvstr) {
137		/* style #3 */
138		if (oargc == -1) {
139			/* Record our original args */
140			oargc = ps_strings->ps_nargvstr;
141			oargv = ps_strings->ps_argvstr;
142			for (nargc = len = 0; nargc < oargc; nargc++) {
143				snprintf(obuf + len, sizeof(obuf) - len, "%s%s",
144				    len ? " " : "", oargv[nargc]);
145				if (len)
146					len++;
147				len += strlen(oargv[nargc]);
148				if (len >= sizeof(obuf))
149					break;
150			}
151		}
152		ps_strings->ps_nargvstr = nargc;
153		ps_strings->ps_argvstr = nargvp;
154	} else {
155		/* style #2 - we can only restore our first arg :-( */
156		if (*obuf == '\0')
157			strncpy(obuf, OLD_PS_STRINGS->old_ps_argvstr,
158			    sizeof(obuf) - 1);
159		OLD_PS_STRINGS->old_ps_nargvstr = 1;
160		OLD_PS_STRINGS->old_ps_argvstr = nargvp[0];
161	}
162}
163