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 1.18 2003/07/01 09:45:35 alfred Exp $
  18  * $DragonFly: src/lib/libc/gen/setproctitle.c,v 1.5 2005/11/13 00:07:42 swildner Exp $
  19  */
  20
  21 #include "namespace.h"
  22 #include <sys/types.h>
  23 #include <sys/param.h>
  24 #include <sys/exec.h>
  25 #include <sys/sysctl.h>
  26
  27 #include <vm/vm.h>
  28 #include <vm/vm_param.h>
  29 #include <vm/pmap.h>
  30
  31 #include <stdio.h>
  32 #include <string.h>
  33 #include <stdlib.h>
  34 #include <unistd.h>
  35 #include "un-namespace.h"
  36
  37 #include "libc_private.h"
  38
  39 /*
  40  * Older FreeBSD 2.0, 2.1 and 2.2 had different ps_strings structures and
  41  * in different locations.
  42  * 1: old_ps_strings at the very top of the stack.
  43  * 2: old_ps_strings at SPARE_USRSPACE below the top of the stack.
  44  * 3: ps_strings at the very top of the stack.
  45  * This attempts to support a kernel built in the #2 and #3 era.
  46  */
  47
  48 struct old_ps_strings {
  49         char    *old_ps_argvstr;
  50         int     old_ps_nargvstr;
  51         char    *old_ps_envstr;
  52         int     old_ps_nenvstr;
  53 };
  54 #define OLD_PS_STRINGS ((struct old_ps_strings *) \
  55         (USRSTACK - SPARE_USRSPACE - sizeof(struct old_ps_strings)))
  56
  57 #include <stdarg.h>
  58
  59 #define SPT_BUFSIZE 2048        /* from other parts of sendmail */
  60
  61 void
  62 setproctitle(const char *fmt, ...)
  63 {
  64         static struct ps_strings *ps_strings;
  65         static char *buf = NULL;
  66         static char *obuf = NULL;
  67         static char **oargv, *kbuf;
  68         static int oargc = -1;
  69         static char *nargv[2] = { NULL, NULL };
  70         char **nargvp;
  71         int nargc;
  72         int i;
  73         va_list ap;
  74         size_t len;
  75         unsigned long ul_ps_strings;
  76         int oid[4];
  77
  78         if (buf == NULL) {
  79                 buf = malloc(SPT_BUFSIZE);
  80                 if (buf == NULL)
  81                         return;
  82                 nargv[0] = buf;
  83         }
  84
  85         if (obuf == NULL ) {
  86                 obuf = malloc(SPT_BUFSIZE);
  87                 if (obuf == NULL)
  88                         return;
  89                 *obuf = '\0';
  90         }
  91
  92         va_start(ap, fmt);
  93
  94         if (fmt) {
  95                 buf[SPT_BUFSIZE - 1] = '\0';
  96
  97                 if (fmt[0] == '-') {
  98                         /* skip program name prefix */
  99                         fmt++;
 100                         len = 0;
 101                 } else {
 102                         /* print program name heading for grep */
 103                         snprintf(buf, SPT_BUFSIZE, "%s: ", _getprogname());
 104                         len = strlen(buf);
 105                 }
 106
 107                 /* print the argument string */
 108                 vsnprintf(buf + len, SPT_BUFSIZE - len, fmt, ap);
 109
 110                 nargvp = nargv;
 111                 nargc = 1;
 112                 kbuf = buf;
 113         } else if (*obuf != '\0') {
 114                 /* Idea from NetBSD - reset the title on fmt == NULL */
 115                 nargvp = oargv;
 116                 nargc = oargc;
 117                 kbuf = obuf;
 118         } else
 119                 /* Nothing to restore */
 120                 return;
 121
 122         va_end(ap);
 123
 124         /* Set the title into the kernel cached command line */
 125         oid[0] = CTL_KERN;
 126         oid[1] = KERN_PROC;
 127         oid[2] = KERN_PROC_ARGS;
 128         oid[3] = getpid();
 129         sysctl(oid, 4, 0, 0, kbuf, strlen(kbuf) + 1);
 130
 131         if (ps_strings == NULL) {
 132                 len = sizeof(ul_ps_strings);
 133                 if (sysctlbyname("kern.ps_strings", &ul_ps_strings, &len, NULL,
 134                     0) == -1)
 135                         ul_ps_strings = PS_STRINGS;
 136                 ps_strings = (struct ps_strings *)ul_ps_strings;
 137         }
 138
 139         /* PS_STRINGS points to zeroed memory on a style #2 kernel */
 140         if (ps_strings->ps_argvstr) {
 141                 /* style #3 */
 142                 if (oargc == -1) {
 143                         /* Record our original args */
 144                         oargc = ps_strings->ps_nargvstr;
 145                         oargv = ps_strings->ps_argvstr;
 146                         for (i = len = 0; i < oargc; i++) {
 147                                 /*
 148                                  * The program may have scribbled into its
 149                                  * argv array, e.g., to remove some arguments.
 150                                  * If that has happened, break out before
 151                                  * trying to call strlen on a NULL pointer.
 152                                  */
 153                                 if (oargv[i] == NULL) {
 154                                         oargc = i;
 155                                         break;
 156                                 }
 157                                 snprintf(obuf + len, SPT_BUFSIZE - len, "%s%s",
 158                                     len ? " " : "", oargv[i]);
 159                                 if (len)
 160                                         len++;
 161                                 len += strlen(oargv[i]);
 162                                 if (len >= SPT_BUFSIZE)
 163                                         break;
 164                         }
 165                 }
 166                 ps_strings->ps_nargvstr = nargc;
 167                 ps_strings->ps_argvstr = nargvp;
 168         } else {
 169                 /* style #2 - we can only restore our first arg :-( */
 170                 if (*obuf == '\0')
 171                         strncpy(obuf, OLD_PS_STRINGS->old_ps_argvstr,
 172                             SPT_BUFSIZE - 1);
 173                 OLD_PS_STRINGS->old_ps_nargvstr = 1;
 174                 OLD_PS_STRINGS->old_ps_argvstr = nargvp[0];
 175         }
 176 }