nostd/setproctitle.c

   1 /* ==========================================================================
   2  * setproctitle.c - Linux/Darwin setproctitle.
   3  * --------------------------------------------------------------------------
   4  * Copyright (C) 2010  William Ahern
   5  *
   6  * Permission is hereby granted, free of charge, to any person obtaining a
   7  * copy of this software and associated documentation files (the
   8  * "Software"), to deal in the Software without restriction, including
   9  * without limitation the rights to use, copy, modify, merge, publish,
  10  * distribute, sublicense, and/or sell copies of the Software, and to permit
  11  * persons to whom the Software is furnished to do so, subject to the
  12  * following conditions:
  13  *
  14  * The above copyright notice and this permission notice shall be included
  15  * in all copies or substantial portions of the Software.
  16  *
  17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  18  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  19  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
  20  * NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
  21  * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
  22  * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
  23  * USE OR OTHER DEALINGS IN THE SOFTWARE.
  24  * ==========================================================================
  25  */
  26 #ifndef _GNU_SOURCE
  27 #define _GNU_SOURCE
  28 #endif
  29
  30 #include <stddef.h>     /* NULL size_t */
  31 #include <stdarg.h>     /* va_list va_start va_end */
  32 #include <stdlib.h>     /* malloc(3) setenv(3) clearenv(3) setproctitle(3) getprogname(3) */
  33 #include <stdio.h>      /* vsnprintf(3) snprintf(3) */
  34
  35 #include <string.h>     /* strlen(3) strchr(3) strdup(3) memset(3) memcpy(3) */
  36
  37 #include <errno.h>      /* errno program_invocation_name program_invocation_short_name */
  38
  39
  40 #if !defined(HAVE_SETPROCTITLE)
  41 #define HAVE_SETPROCTITLE (defined __NetBSD__ || defined __FreeBSD__ || defined __OpenBSD__)
  42 #endif
  43
  44
  45 #if !HAVE_SETPROCTITLE
  46 #if (defined __linux || defined __APPLE__) && defined __GNUC__
  47
  48
  49 static struct {
  50         /* original value */
  51         const char *arg0;
  52
  53         /* title space available */
  54         char *base, *end;
  55
  56          /* pointer to original nul character within base */
  57         char *nul;
  58
  59         _Bool reset;
  60         int error;
  61 } SPT;
  62
  63
  64 #ifndef SPT_MIN
  65 #define SPT_MIN(a, b) (((a) < (b))? (a) : (b))
  66 #endif
  67
  68 static inline size_t spt_min(size_t a, size_t b) {
  69         return SPT_MIN(a, b);
  70 } /* spt_min() */
  71
  72
  73 /*
  74  * For discussion on the portability of the various methods, see
  75  * http://lists.freebsd.org/pipermail/freebsd-stable/2008-June/043136.html
  76  */
  77 static int spt_clearenv(void) {
  78 #if __GLIBC__
  79         clearenv();
  80
  81         return 0;
  82 #else
  83         extern char **environ;
  84         char **tmp;
  85
  86         if (!(tmp = malloc(sizeof *tmp)))
  87                 return errno;
  88
  89         tmp[0]  = NULL;
  90         environ = tmp;
  91
  92         return 0;
  93 #endif
  94 } /* spt_clearenv() */
  95
  96
  97 static int spt_copyenv(char *oldenv[]) {
  98         extern char **environ;
  99         char *eq;
 100         int i, error;
 101
 102         if (environ != oldenv)
 103                 return 0;
 104
 105         if ((error = spt_clearenv()))
 106                 goto error;
 107
 108         for (i = 0; oldenv[i]; i++) {
 109                 if (!(eq = strchr(oldenv[i], '=')))
 110                         continue;
 111
 112                 *eq = '\0';
 113                 error = (0 != setenv(oldenv[i], eq + 1, 1))? errno : 0;
 114                 *eq = '=';
 115
 116                 if (error)
 117                         goto error;
 118         }
 119
 120         return 0;
 121 error:
 122         environ = oldenv;
 123
 124         return error;
 125 } /* spt_copyenv() */
 126
 127
 128 static int spt_copyargs(int argc, char *argv[]) {
 129         char *tmp;
 130         int i;
 131
 132         for (i = 1; i < argc || (i >= argc && argv[i]); i++) {
 133                 if (!argv[i])
 134                         continue;
 135
 136                 if (!(tmp = strdup(argv[i])))
 137                         return errno;
 138
 139                 argv[i] = tmp;
 140         }
 141
 142         return 0;
 143 } /* spt_copyargs() */
 144
 145 void spt_init(int argc, char *argv[], char *envp[]) {
 146         char *base, *end, *nul, *tmp;
 147         int i, error;
 148
 149         if (!(base = argv[0]))
 150                 return;
 151
 152         nul = &base[strlen(base)];
 153         end = nul + 1;
 154
 155         for (i = 0; i < argc || (i >= argc && argv[i]); i++) {
 156                 if (!argv[i] || argv[i] < end)
 157                         continue;
 158
 159                 end = argv[i] + strlen(argv[i]) + 1;
 160         }
 161
 162         for (i = 0; envp[i]; i++) {
 163                 if (envp[i] < end)
 164                         continue;
 165
 166                 end = envp[i] + strlen(envp[i]) + 1;
 167         }
 168
 169         if (!(SPT.arg0 = strdup(argv[0])))
 170                 goto syerr;
 171
 172 #if __GLIBC__
 173         if (!(tmp = strdup(program_invocation_name)))
 174                 goto syerr;
 175
 176         program_invocation_name = tmp;
 177
 178         if (!(tmp = strdup(program_invocation_short_name)))
 179                 goto syerr;
 180
 181         program_invocation_short_name = tmp;
 182 #elif __APPLE__
 183         if (!(tmp = strdup(getprogname())))
 184                 goto syerr;
 185
 186         setprogname(tmp);
 187 #endif
 188
 189
 190         if ((error = spt_copyenv(envp)))
 191                 goto error;
 192
 193         if ((error = spt_copyargs(argc, argv)))
 194                 goto error;
 195
 196         SPT.nul  = nul;
 197         SPT.base = base;
 198         SPT.end  = end;
 199
 200         return;
 201 syerr:
 202         error = errno;
 203 error:
 204         SPT.error = error;
 205 } /* spt_init() */
 206
 207
 208 #ifndef SPT_MAXTITLE
 209 #define SPT_MAXTITLE 255
 210 #endif
 211
 212 void setproctitle(const char *fmt, ...) {
 213         char buf[SPT_MAXTITLE + 1]; /* use buffer in case argv[0] is passed */
 214         va_list ap;
 215         char *nul;
 216         int len, error;
 217
 218         if (!SPT.base)
 219                 return;
 220
 221         if (fmt) {
 222                 va_start(ap, fmt);
 223                 len = vsnprintf(buf, sizeof buf, fmt, ap);
 224                 va_end(ap);
 225         } else {
 226                 len = snprintf(buf, sizeof buf, "%s", SPT.arg0);
 227         }
 228
 229         if (len <= 0)
 230                 { error = errno; goto error; }
 231
 232         if (!SPT.reset) {
 233                 memset(SPT.base, 0, SPT.end - SPT.base);
 234                 SPT.reset = 1;
 235         } else {
 236                 memset(SPT.base, 0, spt_min(sizeof buf, SPT.end - SPT.base));
 237         }
 238
 239         len = spt_min(len, spt_min(sizeof buf, SPT.end - SPT.base) - 1);
 240         memcpy(SPT.base, buf, len);
 241         nul = &SPT.base[len];
 242
 243         if (nul < SPT.nul) {
 244                 *SPT.nul = '.';
 245         } else if (nul == SPT.nul && &nul[1] < SPT.end) {
 246                 *SPT.nul = ' ';
 247                 *++nul = '\0';
 248         }
 249
 250         return;
 251 error:
 252         SPT.error = error;
 253 } /* setproctitle() */
 254
 255
 256 #endif /* __linux || __APPLE__ */
 257 #endif /* !HAVE_SETPROCTITLE */