setproctitle.c revision 64094 
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 64094 2000-08-01 06:37:09Z ps $
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#include <stdarg.h>
53
54#define SPT_BUFSIZE 2048	/* from other parts of sendmail */
55extern char * __progname;	/* is this defined in a .h anywhere? */
56
57void
58setproctitle(const char *fmt, ...)
59{
60	static struct ps_strings *ps_strings;
61	static char buf[SPT_BUFSIZE];
62	static char obuf[SPT_BUFSIZE];
63	static char **oargv, *kbuf;
64	static int oargc = -1;
65	static char *nargv[2] = { buf, NULL };
66	char **nargvp;
67	int nargc;
68	va_list ap;
69	size_t len;
70	unsigned long ul_ps_strings;
71	int oid[4];
72
73	va_start(ap, fmt);
74
75	if (fmt) {
76		buf[sizeof(buf) - 1] = '\0';
77
78		if (fmt[0] == '-') {
79			/* skip program name prefix */
80			fmt++;
81			len = 0;
82		} else {
83			/* print program name heading for grep */
84			(void) snprintf(buf, sizeof(buf), "%s: ", __progname);
85			len = strlen(buf);
86		}
87
88		/* print the argument string */
89		(void) vsnprintf(buf + len, sizeof(buf) - len, fmt, ap);
90
91		nargvp = nargv;
92		nargc = 1;
93		kbuf = buf;
94	} else if (*obuf != '\0') {
95  		/* Idea from NetBSD - reset the title on fmt == NULL */
96		nargvp = oargv;
97		nargc = oargc;
98		kbuf = obuf;
99	} else
100		/* Nothing to restore */
101		return;
102
103	va_end(ap);
104
105	/* Set the title into the kernel cached command line */
106	oid[0] = CTL_KERN;
107	oid[1] = KERN_PROC;
108	oid[2] = KERN_PROC_ARGS;
109	oid[3] = getpid();
110	sysctl(oid, 4, 0, 0, kbuf, strlen(kbuf) + 1);
111
112	if (ps_strings == NULL) {
113		len = sizeof(ul_ps_strings);
114		if (sysctlbyname("kern.ps_strings", &ul_ps_strings, &len, NULL,
115		    0) == -1)
116			ul_ps_strings = PS_STRINGS;
117		ps_strings = (struct ps_strings *)ul_ps_strings;
118	}
119
120	/* PS_STRINGS points to zeroed memory on a style #2 kernel */
121	if (ps_strings->ps_argvstr) {
122		/* style #3 */
123		if (oargc == -1) {
124			/* Record our original args */
125			oargc = ps_strings->ps_nargvstr;
126			oargv = ps_strings->ps_argvstr;
127			for (nargc = len = 0; nargc < oargc; nargc++) {
128				snprintf(obuf + len, sizeof(obuf) - len, "%s%s",
129				    len ? " " : "", oargv[nargc]);
130				if (len)
131					len++;
132				len += strlen(oargv[nargc]);
133				if (len >= sizeof(obuf))
134					break;
135			}
136		}
137		ps_strings->ps_nargvstr = nargc;
138		ps_strings->ps_argvstr = nargvp;
139	} else {
140		/* style #2 - we can only restore our first arg :-( */
141		if (*obuf == '\0')
142			strncpy(obuf, OLD_PS_STRINGS->old_ps_argvstr,
143			    sizeof(obuf) - 1);
144		OLD_PS_STRINGS->old_ps_nargvstr = 1;
145		OLD_PS_STRINGS->old_ps_argvstr = nargvp[0];
146	}
147}
148