util.c

   1 /*
   2  * Copyright (c) 2008 The DragonFly Project.  All rights reserved.
   3  *
   4  * This code is derived from software contributed to The DragonFly Project
   5  * by Simon 'corecode' Schubert <corecode@fs.ei.tum.de>.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  *
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in
  15  *    the documentation and/or other materials provided with the
  16  *    distribution.
  17  * 3. Neither the name of The DragonFly Project nor the names of its
  18  *    contributors may be used to endorse or promote products derived
  19  *    from this software without specific, prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  22  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  23  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  24  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
  25  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  26  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
  27  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  28  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
  29  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  30  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
  31  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  32  * SUCH DAMAGE.
  33  */
  34
  35 #include <sys/param.h>
  36 #include <sys/file.h>
  37
  38 #include <ctype.h>
  39 #include <errno.h>
  40 #include <fcntl.h>
  41 #include <netdb.h>
  42 #include <pwd.h>
  43 #include <setjmp.h>
  44 #include <signal.h>
  45 #include <stdio.h>
  46 #include <syslog.h>
  47 #include <unistd.h>
  48
  49 #include "dma.h"
  50
  51 const char *
  52 hostname(void)
  53 {
  54         static char name[HOST_NAME_MAX+1];
  55         static int initialized = 0;
  56         char *s;
  57
  58         if (initialized)
  59                 return (name);
  60
  61         if (config.mailname == NULL || !*config.mailname)
  62                 goto local;
  63
  64         if (config.mailname[0] == '/') {
  65                 /*
  66                  * If the mailname looks like an absolute path,
  67                  * treat it as a file.
  68                  */
  69                 FILE *fp;
  70
  71                 fp = fopen(config.mailname, "r");
  72                 if (fp == NULL)
  73                         goto local;
  74
  75                 s = fgets(name, sizeof(name), fp);
  76                 fclose(fp);
  77                 if (s == NULL)
  78                         goto local;
  79
  80                 for (s = name; *s != 0 && (isalnum(*s) || strchr("_.-", *s)); ++s)
  81                         /* NOTHING */;
  82                 *s = 0;
  83
  84                 if (!*name)
  85                         goto local;
  86
  87                 initialized = 1;
  88                 return (name);
  89         } else {
  90                 snprintf(name, sizeof(name), "%s", config.mailname);
  91                 initialized = 1;
  92                 return (name);
  93         }
  94
  95 local:
  96         if (gethostname(name, sizeof(name)) != 0)
  97                 *name = 0;
  98         /*
  99          * gethostname() is allowed to truncate name without NUL-termination
 100          * and at the same time not return an error.
 101          */
 102         name[sizeof(name) - 1] = 0;
 103
 104         for (s = name; *s != 0 && (isalnum(*s) || strchr("_.-", *s)); ++s)
 105                 /* NOTHING */;
 106         *s = 0;
 107
 108         if (!*name)
 109                 snprintf(name, sizeof(name), "unknown-hostname");
 110
 111         initialized = 1;
 112         return (name);
 113 }
 114
 115 void
 116 setlogident(const char *fmt, ...)
 117 {
 118         static char tag[50];
 119
 120         snprintf(tag, sizeof(tag), "%s", logident_base);
 121         if (fmt != NULL) {
 122                 va_list ap;
 123                 char sufx[50];
 124
 125                 va_start(ap, fmt);
 126                 vsnprintf(sufx, sizeof(sufx), fmt, ap);
 127                 va_end(ap);
 128                 snprintf(tag, sizeof(tag), "%s[%s]", logident_base, sufx);
 129         }
 130         closelog();
 131         openlog(tag, 0, LOG_MAIL);
 132 }
 133
 134 void
 135 errlog(int exitcode, const char *fmt, ...)
 136 {
 137         int oerrno = errno;
 138         va_list ap;
 139         char outs[ERRMSG_SIZE];
 140
 141         outs[0] = 0;
 142         if (fmt != NULL) {
 143                 va_start(ap, fmt);
 144                 vsnprintf(outs, sizeof(outs), fmt, ap);
 145                 va_end(ap);
 146         }
 147
 148         if (*outs != 0) {
 149                 syslog(LOG_ERR, "%s: %m", outs);
 150                 fprintf(stderr, "%s: %s: %s\n", getprogname(), outs, strerror(oerrno));
 151         } else {
 152                 syslog(LOG_ERR, "%m");
 153                 fprintf(stderr, "%s: %s\n", getprogname(), strerror(oerrno));
 154         }
 155
 156         exit(exitcode);
 157 }
 158
 159 void
 160 errlogx(int exitcode, const char *fmt, ...)
 161 {
 162         va_list ap;
 163         char outs[ERRMSG_SIZE];
 164
 165         outs[0] = 0;
 166         if (fmt != NULL) {
 167                 va_start(ap, fmt);
 168                 vsnprintf(outs, sizeof(outs), fmt, ap);
 169                 va_end(ap);
 170         }
 171
 172         if (*outs != 0) {
 173                 syslog(LOG_ERR, "%s", outs);
 174                 fprintf(stderr, "%s: %s\n", getprogname(), outs);
 175         } else {
 176                 syslog(LOG_ERR, "Unknown error");
 177                 fprintf(stderr, "%s: Unknown error\n", getprogname());
 178         }
 179
 180         exit(exitcode);
 181 }
 182
 183 static int
 184 check_username(const char *name, uid_t ckuid)
 185 {
 186         struct passwd *pwd;
 187
 188         if (name == NULL)
 189                 return (0);
 190         pwd = getpwnam(name);
 191         if (pwd == NULL || pwd->pw_uid != ckuid)
 192                 return (0);
 193         snprintf(username, sizeof(username), "%s", name);
 194         return (1);
 195 }
 196
 197 void
 198 set_username(void)
 199 {
 200         struct passwd *pwd;
 201
 202         useruid = getuid();
 203         if (check_username(getlogin(), useruid))
 204                 return;
 205         if (check_username(getenv("LOGNAME"), useruid))
 206                 return;
 207         if (check_username(getenv("USER"), useruid))
 208                 return;
 209         pwd = getpwuid(useruid);
 210         if (pwd != NULL && pwd->pw_name != NULL && pwd->pw_name[0] != '\0') {
 211                 if (check_username(pwd->pw_name, useruid))
 212                         return;
 213         }
 214         snprintf(username, sizeof(username), "uid=%ld", (long)useruid);
 215 }
 216
 217 void
 218 deltmp(void)
 219 {
 220         struct stritem *t;
 221
 222         SLIST_FOREACH(t, &tmpfs, next) {
 223                 unlink(t->str);
 224         }
 225 }
 226
 227 static sigjmp_buf sigbuf;
 228 static int sigbuf_valid;
 229
 230 static void
 231 sigalrm_handler(int signo)
 232 {
 233         (void)signo;    /* so that gcc doesn't complain */
 234         if (sigbuf_valid)
 235                 siglongjmp(sigbuf, 1);
 236 }
 237
 238 int
 239 do_timeout(int timeout, int dojmp)
 240 {
 241         struct sigaction act;
 242         int ret = 0;
 243
 244         sigemptyset(&act.sa_mask);
 245         act.sa_flags = 0;
 246
 247         if (timeout) {
 248                 act.sa_handler = sigalrm_handler;
 249                 if (sigaction(SIGALRM, &act, NULL) != 0)
 250                         syslog(LOG_WARNING, "can not set signal handler: %m");
 251                 if (dojmp) {
 252                         ret = sigsetjmp(sigbuf, 1);
 253                         if (ret)
 254                                 goto disable;
 255                         /* else just programmed */
 256                         sigbuf_valid = 1;
 257                 }
 258
 259                 alarm(timeout);
 260         } else {
 261 disable:
 262                 alarm(0);
 263
 264                 act.sa_handler = SIG_IGN;
 265                 if (sigaction(SIGALRM, &act, NULL) != 0)
 266                         syslog(LOG_WARNING, "can not remove signal handler: %m");
 267                 sigbuf_valid = 0;
 268         }
 269
 270         return (ret);
 271 }
 272
 273 int
 274 open_locked(const char *fname, int flags, ...)
 275 {
 276         int mode = 0;
 277
 278         if (flags & O_CREAT) {
 279                 va_list ap;
 280                 va_start(ap, flags);
 281                 mode = va_arg(ap, int);
 282                 va_end(ap);
 283         }
 284
 285 #ifndef O_EXLOCK
 286         int fd, save_errno;
 287
 288         fd = open(fname, flags, mode);
 289         if (fd < 0)
 290                 return(fd);
 291         if (flock(fd, LOCK_EX|((flags & O_NONBLOCK)? LOCK_NB: 0)) < 0) {
 292                 save_errno = errno;
 293                 close(fd);
 294                 errno = save_errno;
 295                 return(-1);
 296         }
 297         return(fd);
 298 #else
 299         return(open(fname, flags|O_EXLOCK, mode));
 300 #endif
 301 }
 302
 303 char *
 304 rfc822date(void)
 305 {
 306         static char str[50];
 307         size_t error;
 308         time_t now;
 309
 310         now = time(NULL);
 311         error = strftime(str, sizeof(str), "%a, %d %b %Y %T %z",
 312                        localtime(&now));
 313         if (error == 0)
 314                 strcpy(str, "(date fail)");
 315         return (str);
 316 }
 317
 318 int
 319 strprefixcmp(const char *str, const char *prefix)
 320 {
 321         return (strncasecmp(str, prefix, strlen(prefix)));
 322 }
 323
 324 void
 325 init_random(void)
 326 {
 327         unsigned int seed;
 328         int rf;
 329
 330         rf = open("/dev/urandom", O_RDONLY);
 331         if (rf == -1)
 332                 rf = open("/dev/random", O_RDONLY);
 333
 334         if (!(rf != -1 && read(rf, &seed, sizeof(seed)) == sizeof(seed)))
 335                 seed = (time(NULL) ^ getpid()) + (uintptr_t)&seed;
 336
 337         srandom(seed);
 338
 339         if (rf != -1)
 340                 close(rf);
 341 }