lib/libc/gen/setproctitle.c

   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: src/lib/libc/gen/setproctitle.c,v 1.12.2.2 2000/12/10 20:27:08 jdp Exp $
  18  * $DragonFly: src/lib/libc/gen/setproctitle.c,v 1.5 2005/11/13 00:07:42 swildner Exp $
  19  */
  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
  44 struct 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 */
  56
  57 void
  58 setproctitle(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         int i;
  69         va_list ap;
  70         size_t len;
  71         unsigned long ul_ps_strings;
  72         int oid[4];
  73
  74         va_start(ap, fmt);
  75
  76         if (fmt) {
  77                 buf[sizeof(buf) - 1] = '\0';
  78
  79                 if (fmt[0] == '-') {
  80                         /* skip program name prefix */
  81                         fmt++;
  82                         len = 0;
  83                 } else {
  84                         /* print program name heading for grep */
  85                         snprintf(buf, sizeof(buf), "%s: ", getprogname());
  86                         len = strlen(buf);
  87                 }
  88
  89                 /* print the argument string */
  90                 vsnprintf(buf + len, sizeof(buf) - len, fmt, ap);
  91
  92                 nargvp = nargv;
  93                 nargc = 1;
  94                 kbuf = buf;
  95         } else if (*obuf != '\0') {
  96                 /* Idea from NetBSD - reset the title on fmt == NULL */
  97                 nargvp = oargv;
  98                 nargc = oargc;
  99                 kbuf = obuf;
 100         } else
 101                 /* Nothing to restore */
 102                 return;
 103
 104         va_end(ap);
 105
 106         /* Set the title into the kernel cached command line */
 107         oid[0] = CTL_KERN;
 108         oid[1] = KERN_PROC;
 109         oid[2] = KERN_PROC_ARGS;
 110         oid[3] = getpid();
 111         sysctl(oid, 4, 0, 0, kbuf, strlen(kbuf) + 1);
 112
 113 #ifdef __i386__
 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 #endif
 160 }