unix4lyfe git - darkstat/blob - err.c

   1 /* darkstat 3
   2  * copyright (c) 2001-2008 Emil Mikulic.
   3  *
   4  * err.c: BSD-like err() and warn() functions
   5  *
   6  * Permission to use, copy, modify, and distribute this file for any
   7  * purpose with or without fee is hereby granted, provided that the above
   8  * copyright notice and this permission notice appear in all copies.
   9  *
  10  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  11  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  12  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  13  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  14  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  15  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  16  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  17  */
  18
  19 #include "darkstat.h"
  20 #include "err.h"
  21 #include "pidfile.h"
  22
  23 #include <errno.h>
  24 #include <stdarg.h>
  25 #include <stdio.h>
  26 #include <stdlib.h>
  27 #include <string.h>
  28 #include <unistd.h>
  29 #include <unistd.h>
  30
  31 void
  32 err(const int code, const char *format, ...)
  33 {
  34    va_list va;
  35
  36    fprintf(stderr, "%5d: error: ", (int)getpid());
  37    va_start(va, format);
  38    vfprintf(stderr, format, va);
  39    va_end(va);
  40    fprintf(stderr, ": %s\n", strerror(errno));
  41    pidfile_unlink();
  42    exit(code);
  43 }
  44
  45 void
  46 errx(const int code, const char *format, ...)
  47 {
  48    va_list va;
  49
  50    fprintf(stderr, "%5d: error: ", (int)getpid());
  51    va_start(va, format);
  52    vfprintf(stderr, format, va);
  53    va_end(va);
  54    fprintf(stderr, "\n");
  55    pidfile_unlink();
  56    exit(code);
  57 }
  58
  59 void
  60 warn(const char *format, ...)
  61 {
  62    va_list va;
  63
  64    fprintf(stderr, "%5d: warning: ", (int)getpid());
  65    va_start(va, format);
  66    vfprintf(stderr, format, va);
  67    va_end(va);
  68    fprintf(stderr, ": %s\n", strerror(errno));
  69 }
  70
  71 void
  72 warnx(const char *format, ...)
  73 {
  74    va_list va;
  75
  76    fprintf(stderr, "%5d: warning: ", (int)getpid());
  77    va_start(va, format);
  78    vfprintf(stderr, format, va);
  79    va_end(va);
  80    fprintf(stderr, "\n");
  81 }
  82
  83 /* We interlock verbosef() between processes by using a pipe with a single
  84  * byte in it.  This pipe must be initialized before the first fork() in order
  85  * to work.  Then, verbosef() will block on a read() until it is able to
  86  * retrieve the byte.  After doing its business, it will put a byte back into
  87  * the pipe.
  88  *
  89  * This is completely silly and largely unnecessary.
  90  */
  91 static int inited = 0;
  92 static int lockpipe[2];
  93
  94 static void unlock(void);
  95
  96 static void
  97 initlock(void)
  98 {
  99    if (pipe(lockpipe) == -1)
 100       err(1, "pipe(lockpipe)");
 101    inited = 1;
 102    unlock();
 103 }
 104
 105 static void
 106 lock(void)
 107 {
 108    char buf[1];
 109
 110    if (!inited) initlock();
 111    if (read(lockpipe[0], buf, 1) != 1) {
 112       fprintf(stderr, "lock failed!\n");
 113       pidfile_unlink();
 114       exit(1);
 115    }
 116 }
 117
 118 static void
 119 unlock(void)
 120 {
 121    char c = 0;
 122
 123    if (write(lockpipe[1], &c, 1) != 1) {
 124       fprintf(stderr, "unlock failed!\n");
 125       pidfile_unlink();
 126       exit(1);
 127    }
 128 }
 129
 130 int want_verbose = 0;
 131
 132 void
 133 verbosef(const char *format, ...)
 134 {
 135    va_list va;
 136
 137    if (!want_verbose) return;
 138    lock();
 139    fprintf(stderr, "darkstat (%05d): ", (int)getpid());
 140    va_start(va, format);
 141    vfprintf(stderr, format, va);
 142    va_end(va);
 143    fprintf(stderr, "\n");
 144    unlock();
 145 }
 146
 147 void
 148 dverbosef(const char *format _unused_, ...)
 149 {
 150    /* disabled / do-nothing verbosef */
 151 }
 152
 153 /* vim:set ts=3 sw=3 tw=78 expandtab: */