lib/dpkg/debug.c

   1 /*
   2  * libdpkg - Debian packaging suite library routines
   3  * debug.c - debugging support
   4  *
   5  * Copyright © 1995 Ian Jackson <ijackson@chiark.greenend.org.uk>
   6  * Copyright © 2011 Guillem Jover <guillem@debian.org>
   7  *
   8  * This is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; either version 2 of the License, or
  11  * (at your option) any later version.
  12  *
  13  * This is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  20  */
  21
  22 #include <config.h>
  23 #include <compat.h>
  24
  25 #include <errno.h>
  26 #include <stdarg.h>
  27 #include <stdlib.h>
  28 #include <stdio.h>
  29
  30 #include <dpkg/dpkg.h>
  31 #include <dpkg/i18n.h>
  32 #include <dpkg/report.h>
  33 #include <dpkg/debug.h>
  34
  35 static int debug_mask = 0;
  36 static FILE *debug_output = NULL;
  37
  38 /**
  39  * Set the debugging output file.
  40  *
  41  * Marks the file descriptor as close-on-exec.
  42  */
  43 void
  44 debug_set_output(FILE *output, const char *filename)
  45 {
  46         setcloexec(fileno(output), filename);
  47         dpkg_set_report_buffer(output);
  48         debug_output = output;
  49 }
  50
  51 /**
  52  * Set the debugging mask.
  53  *
  54  * The mask determines what debugging flags are going to take effect at
  55  * run-time. The output will be set to stderr if it has not been set before.
  56  */
  57 void
  58 debug_set_mask(int mask)
  59 {
  60         debug_mask = mask;
  61         if (!debug_output)
  62                 debug_output = stderr;
  63 }
  64
  65 /**
  66  * Parse the debugging mask.
  67  *
  68  * The mask is parsed from the specified string and sets the global debugging
  69  * mask. If there is any error while parsing a negative number is returned.
  70  */
  71 int
  72 debug_parse_mask(const char *str)
  73 {
  74         char *endp;
  75         long mask;
  76
  77         errno = 0;
  78         mask = strtol(str, &endp, 8);
  79         if (str == endp || *endp || mask < 0 || errno == ERANGE)
  80                 return -1;
  81
  82         debug_set_mask(mask);
  83
  84         return mask;
  85 }
  86
  87 /**
  88  * Check if a debugging flag is currently set on the debugging mask.
  89  */
  90 bool
  91 debug_has_flag(int flag)
  92 {
  93         return debug_mask & flag;
  94 }
  95
  96 /**
  97  * Output a debugging message.
  98  *
  99  * The message will be printed to the previously specified output if the
 100  * specified flag is present in the current debugging mask.
 101  */
 102 void
 103 debug(int flag, const char *fmt, ...)
 104 {
 105         va_list args;
 106
 107         if (!debug_has_flag(flag))
 108                 return;
 109
 110         fprintf(debug_output, "D0%05o: ", flag);
 111         va_start(args, fmt);
 112         vfprintf(debug_output, fmt, args);
 113         va_end(args);
 114         putc('\n', debug_output);
 115 }
 116
 117 /**
 118  * Initialize the debugging support.
 119  */
 120 void
 121 dpkg_debug_init(void)
 122 {
 123         const char envvar[] = "DPKG_DEBUG";
 124         const char *env;
 125
 126         env = getenv(envvar);
 127         if (env == NULL)
 128                 return;
 129
 130         if (debug_parse_mask(env) < 0)
 131                 warning(_("cannot parse debug mask from environment variable %s"),
 132                         envvar);
 133 }