setproctitle.c revision 90039 
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
18#include <sys/cdefs.h>
19__FBSDID("$FreeBSD: head/lib/libc/gen/setproctitle.c 90039 2002-02-01 00:57:29Z obrien $");
20
21#include <sys/types.h>
22#include <sys/param.h>
23#include <sys/exec.h>
24#include <sys/sysctl.h>
25
26#include <vm/vm.h>
27#include <vm/vm_param.h>
28#include <vm/pmap.h>
29
30#include <stdio.h>
31#include <string.h>
32#include <stdlib.h>
33#include <unistd.h>
34
35/*
36 * Older FreeBSD 2.0, 2.1 and 2.2 had different ps_strings structures and
37 * in different locations.
38 * 1: old_ps_strings at the very top of the stack.
39 * 2: old_ps_strings at SPARE_USRSPACE below the top of the stack.
40 * 3: ps_strings at the very top of the stack.
41 * This attempts to support a kernel built in the #2 and #3 era.
42 */
43
44struct old_ps_strings {
45	char	*old_ps_argvstr;
46	int	old_ps_nargvstr;
47	char	*old_ps_envstr;
48	int	old_ps_nenvstr;
49};
50#define	OLD_PS_STRINGS ((struct old_ps_strings *) \
51	(USRSTACK - SPARE_USRSPACE - sizeof(struct old_ps_strings)))
52
53#include <stdarg.h>
54
55#define SPT_BUFSIZE 2048	/* from other parts of sendmail */
56extern char * __progname;	/* is this defined in a .h anywhere? */
57
58void
59setproctitle(const char *fmt, ...)
60{
61	static struct ps_strings *ps_strings;
62	static char buf[SPT_BUFSIZE];
63	static char obuf[SPT_BUFSIZE];
64	static char **oargv, *kbuf;
65	static int oargc = -1;
66	static char *nargv[2] = { buf, NULL };
67	char **nargvp;
68	int nargc;
69	int i;
70	va_list ap;
71	size_t len;
72	unsigned long ul_ps_strings;
73	int oid[4];
74
75	va_start(ap, fmt);
76
77	if (fmt) {
78		buf[sizeof(buf) - 1] = '\0';
79
80		if (fmt[0] == '-') {
81			/* skip program name prefix */
82			fmt++;
83			len = 0;
84		} else {
85			/* print program name heading for grep */
86			(void) snprintf(buf, sizeof(buf), "%s: ", __progname);
87			len = strlen(buf);
88		}
89
90		/* print the argument string */
91		(void) vsnprintf(buf + len, sizeof(buf) - len, fmt, ap);
92
93		nargvp = nargv;
94		nargc = 1;
95		kbuf = buf;
96	} else if (*obuf != '\0') {
97  		/* Idea from NetBSD - reset the title on fmt == NULL */
98		nargvp = oargv;
99		nargc = oargc;
100		kbuf = obuf;
101	} else
102		/* Nothing to restore */
103		return;
104
105	va_end(ap);
106
107	/* Set the title into the kernel cached command line */
108	oid[0] = CTL_KERN;
109	oid[1] = KERN_PROC;
110	oid[2] = KERN_PROC_ARGS;
111	oid[3] = getpid();
112	sysctl(oid, 4, 0, 0, kbuf, strlen(kbuf) + 1);
113
114	if (ps_strings == NULL) {
115		len = sizeof(ul_ps_strings);
116		if (sysctlbyname("kern.ps_strings", &ul_ps_strings, &len, NULL,
117		    0) == -1)
118			ul_ps_strings = PS_STRINGS;
119		ps_strings = (struct ps_strings *)ul_ps_strings;
120	}
121
122	/* PS_STRINGS points to zeroed memory on a style #2 kernel */
123	if (ps_strings->ps_argvstr) {
124		/* style #3 */
125		if (oargc == -1) {
126			/* Record our original args */
127			oargc = ps_strings->ps_nargvstr;
128			oargv = ps_strings->ps_argvstr;
129			for (i = len = 0; i < oargc; i++) {
130				/*
131				 * The program may have scribbled into its
132				 * argv array, e.g., to remove some arguments.
133				 * If that has happened, break out before
134				 * trying to call strlen on a NULL pointer.
135				 */
136				if (oargv[i] == NULL) {
137					oargc = i;
138					break;
139				}
140				snprintf(obuf + len, sizeof(obuf) - len, "%s%s",
141				    len ? " " : "", oargv[i]);
142				if (len)
143					len++;
144				len += strlen(oargv[i]);
145				if (len >= sizeof(obuf))
146					break;
147			}
148		}
149		ps_strings->ps_nargvstr = nargc;
150		ps_strings->ps_argvstr = nargvp;
151	} else {
152		/* style #2 - we can only restore our first arg :-( */
153		if (*obuf == '\0')
154			strncpy(obuf, OLD_PS_STRINGS->old_ps_argvstr,
155			    sizeof(obuf) - 1);
156		OLD_PS_STRINGS->old_ps_nargvstr = 1;
157		OLD_PS_STRINGS->old_ps_argvstr = nargvp[0];
158	}
159}
160