xref: /freebsd/lib/libc/gen/setproctitle.c (revision 4cf49a43559ed9fdad601bdcccd2c55963008675)
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  * $FreeBSD$
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 
33 /*
34  * Older FreeBSD 2.0, 2.1 and 2.2 had different ps_strings structures and
35  * in different locations.
36  * 1: old_ps_strings at the very top of the stack.
37  * 2: old_ps_strings at SPARE_USRSPACE below the top of the stack.
38  * 3: ps_strings at the very top of the stack.
39  * This attempts to support a kernel built in the #2 and #3 era.
40  */
41 
42 struct old_ps_strings {
43 	char	*old_ps_argvstr;
44 	int	old_ps_nargvstr;
45 	char	*old_ps_envstr;
46 	int	old_ps_nenvstr;
47 };
48 #define	OLD_PS_STRINGS ((struct old_ps_strings *) \
49 	(USRSTACK - SPARE_USRSPACE - sizeof(struct old_ps_strings)))
50 
51 #if defined(__STDC__)		/* from other parts of sendmail */
52 #include <stdarg.h>
53 #else
54 #include <varargs.h>
55 #endif
56 
57 
58 #define SPT_BUFSIZE 2048	/* from other parts of sendmail */
59 extern char * __progname;	/* is this defined in a .h anywhere? */
60 
61 static struct ps_strings *ps_strings;
62 
63 void
64 #if defined(__STDC__)
65 setproctitle(const char *fmt, ...)
66 #else
67 setproctitle(fmt, va_alist)
68 	const char *fmt;
69 	va_dcl
70 #endif
71 {
72 	static char buf[SPT_BUFSIZE];
73 	static char *ps_argv[2];
74 	va_list ap;
75 	size_t len;
76 	unsigned long ul_ps_strings;
77 
78 #if defined(__STDC__)
79 	va_start(ap, fmt);
80 #else
81 	va_start(ap);
82 #endif
83 
84 	buf[sizeof(buf) - 1] = '\0';
85 	if (fmt) {
86 
87 		/* print program name heading for grep */
88 		(void) snprintf(buf, sizeof(buf) - 1, "%s: ", __progname);
89 
90 		/*
91 		 * can't use return from sprintf, as that is the count of how
92 		 * much it wanted to write, not how much it actually did.
93 		 */
94 
95 		len = strlen(buf);
96 
97 		/* print the argument string */
98 		(void) vsnprintf(buf + len, sizeof(buf) - 1 - len, fmt, ap);
99 	} else {
100 		/* Idea from NetBSD - reset the title on fmt == NULL */
101 		strncpy(buf, __progname, sizeof(buf) - 1);
102 	}
103 
104 	va_end(ap);
105 
106 	if (ps_strings == NULL) {
107 		len = sizeof(ul_ps_strings);
108 		if (sysctlbyname("kern.ps_strings", &ul_ps_strings, &len, NULL,
109 		    0) == -1)
110 			ul_ps_strings = PS_STRINGS;
111 		ps_strings = (struct ps_strings *)ul_ps_strings;
112 	}
113 
114 	/* PS_STRINGS points to zeroed memory on a style #2 kernel */
115 	if (ps_strings->ps_argvstr) {
116 		/* style #3 */
117 		ps_argv[0] = buf;
118 		ps_argv[1] = NULL;
119 		ps_strings->ps_nargvstr = 1;
120 		ps_strings->ps_argvstr = ps_argv;
121 	} else {
122 		/* style #2 */
123 		OLD_PS_STRINGS->old_ps_nargvstr = 1;
124 		OLD_PS_STRINGS->old_ps_argvstr = buf;
125 	}
126 }
127