text: /*
  Copyright (c) 2003-2006 by Juliusz Chroboczek
  
  Permission is hereby granted, free of charge, to any person obtaining a copy
  of this software and associated documentation files (the "Software"), to deal
  in the Software without restriction, including without limitation the rights
  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  copies of the Software, and to permit persons to whom the Software is
  furnished to do so, subject to the following conditions:
  
  The above copyright notice and this permission notice shall be included in
  all copies or substantial portions of the Software.
  
  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  THE SOFTWARE.
  */
  
  #include "polipo.h"
  
  #ifdef HAVE_SYSLOG
  #include <syslog.h>
  #endif
  
  
  static int logLevel = LOGGING_DEFAULT;
  static int logSyslog = 0;
  static AtomPtr logFile = NULL;
  static FILE *logF;
  #ifdef HAVE_SYSLOG
  static AtomPtr logFacility = NULL;
  static int facility;
  #endif
  
  #define STR(x) XSTR(x)
  #define XSTR(x) #x
  
  static void initSyslog(void);
  
  #ifdef HAVE_SYSLOG
  static char *syslogBuf;
  static int syslogBufSize;
  static int syslogBufLength;
  
  static int translateFacility(AtomPtr facility);
  static int translatePriority(int type);
  static void accumulateSyslogV(int type, const char *f, va_list args);
  static void accumulateSyslogN(int type, const char *s, int len);
  #endif
  
  void
  preinitLog()
  {
      CONFIG_VARIABLE_SETTABLE(logLevel, CONFIG_HEX, configIntSetter,
                               "Logging level (max = " STR(LOGGING_MAX) ").");
      CONFIG_VARIABLE(logFile, CONFIG_ATOM, "Log file (stderr if empty and logSyslog is unset).");
  
  #ifdef HAVE_SYSLOG
      CONFIG_VARIABLE(logSyslog, CONFIG_BOOLEAN, "Log to syslog.");
      CONFIG_VARIABLE(logFacility, CONFIG_ATOM, "Syslog facility to use.");
      logFacility = internAtom("user");
  #endif
  
      logF = stderr;
  }
  
  int
  loggingToStderr(void) {
      return(logF == stderr);
  }
  
  void
  initLog(void)
  {
      if(daemonise && logFile == NULL && !logSyslog)
          logFile = internAtom("/var/log/polipo");
  
      if(logFile != NULL && logFile->length > 0) {
          FILE *f;
          f = fopen(logFile->string, "a");
          if(f == NULL) {
              do_log_error(L_ERROR, errno, "Couldn't open log file %s",
                           logFile->string);
              exit(1);
          }
          setvbuf(f, NULL, _IOLBF, 0);
          logF = f;
      }
  
      if(logSyslog) {
          initSyslog();
  
          if(logFile == NULL) {
              logF = NULL;
          }
      }
  }
  
  #ifdef HAVE_SYSLOG
  static void
  initSyslog()
  {
      if(logSyslog) {
          facility = translateFacility(logFacility);
          closelog();
          openlog("polipo", LOG_PID, facility);
  
          if(!syslogBuf) {
              syslogBuf = strdup("");
              syslogBufSize = 1;
          }
      }
  }
  
  /* Map a user-provided name to a syslog facility.
  
     This is rendered quite ugly because POSIX hardly defines any, but we
     should allow any the local system knows about. */
  
  static int
  translateFacility(AtomPtr facility)
  {
      typedef struct
      {
          const char *name;
          int facility;
      } FacilitiesRec;
  
      /* List of all known valid syslog facilities.
  
         This list is terminated by a NULL facility name. */
  
      FacilitiesRec facilities[] = {
          /* These are all the facilities found in glibc 2.5. */
  #ifdef LOG_AUTH
          { "auth", LOG_AUTH },
  #endif
  #ifdef LOG_AUTHPRIV
          { "authpriv", LOG_AUTHPRIV },
  #endif
  #ifdef LOG_CRON
          { "cron", LOG_CRON },
  #endif
  #ifdef LOG_DAEMON
          { "daemon", LOG_DAEMON },
  #endif
  #ifdef LOG_FTP
          { "ftp", LOG_FTP },
  #endif
  #ifdef LOG_KERN
          { "kern", LOG_KERN },
  #endif
  #ifdef LOG_LPR
          { "lpr", LOG_LPR },
  #endif
  #ifdef LOG_MAIL
          { "mail", LOG_MAIL },
  #endif
  #ifdef LOG_NEWS
          { "news", LOG_NEWS },
  #endif
  #ifdef LOG_SYSLOG
          { "syslog", LOG_SYSLOG },
  #endif
  #ifdef LOG_uucp
          { "uucp", LOG_UUCP },
  #endif
          /* These are required by POSIX. */
          { "user", LOG_USER },
          { "local0", LOG_LOCAL0 },
          { "local1", LOG_LOCAL1 },
          { "local2", LOG_LOCAL2 },
          { "local3", LOG_LOCAL3 },
          { "local4", LOG_LOCAL4 },
          { "local5", LOG_LOCAL5 },
          { "local6", LOG_LOCAL6 },
          { "local7", LOG_LOCAL7 },
          { NULL, 0 }};
  
      FacilitiesRec *current;
  
      /* It would be more fitting to return LOG_DAEMON, but POSIX does not
         guarantee the existence of that facility. */
  
      if(!facility) {
          return LOG_USER;
      }
  
      current = facilities;
      while(current->name) {
          if(!strcmp(current->name, atomString(facility))) {
              return current->facility;
          }
          current++;
      }
  
      /* This will go to stderr because syslog is not yet initialized. */
      do_log(L_ERROR, "Specified logFacility %s nonexistent on this system.",
             atomString(facility));
  
      return LOG_USER;
  }
  
  /* Translate a Polipo error type into a syslog priority. */
  
  static int
  translatePriority(int type)
  {
      typedef struct
      {
          int type;
          int priority;
      } PrioritiesRec;
  
      /* The list is terminated with a type of zero. */
  
      PrioritiesRec priorities[] = {{ L_ERROR, LOG_ERR },
                                    { L_WARN, LOG_WARNING },
                                    { L_INFO, LOG_NOTICE },
                                    { L_FORBIDDEN, LOG_DEBUG },
                                    { L_UNCACHEABLE, LOG_DEBUG },
                                    { L_SUPERSEDED, LOG_DEBUG },
                                    { L_VARY, LOG_DEBUG },
                                    { 0, 0 }};
      PrioritiesRec *current;
  
      current = priorities;
      while(current->type) {
          if(current->type == type) {
              return current->priority;
          }
          current++;
      }
  
      return LOG_DEBUG;
  }
  
  static int
  expandSyslog(int len)
  {
      int newsize;
      char *newbuf;
  
      if(len < 0)
          newsize = syslogBufSize * 2;
      else
          newsize = syslogBufLength + len + 1;
  
      newbuf = realloc(syslogBuf, newsize);
      if(!newbuf)
          return -1;
  
      syslogBuf = newbuf;
      syslogBufSize = newsize;
      return 1;
  }
  
  static void
  maybeFlushSyslog(int type)
  {
      char *linefeed;
      while(1) {
          linefeed = memchr(syslogBuf, '\n', syslogBufLength);
          if(linefeed == NULL)
              break;
          *linefeed = '\0';
          syslog(translatePriority(type), "%s", syslogBuf);
          linefeed++;
          syslogBufLength -= (linefeed - syslogBuf);
          if(syslogBufLength > 0)
              memmove(syslogBuf, linefeed, syslogBufLength);
      }
  }
  
  static void
  accumulateSyslogV(int type, const char *f, va_list args)
  {
      int rc;
  
   again:
      rc = vsnprintf(syslogBuf + syslogBufLength,
                     syslogBufSize - syslogBufLength,
                     f, args);
  
      if(rc < 0 || rc >= syslogBufSize - syslogBufLength) {
          rc = expandSyslog(rc);
          if(rc < 0)
              return;
          goto again;
      }
  
      syslogBufLength += rc;
  
      maybeFlushSyslog(type);
  }
  
  static void
  accumulateSyslogN(int type, const char *s, int len)
  {
      while(syslogBufSize - syslogBufLength <= len)
          expandSyslog(len);
  
      memcpy(syslogBuf + syslogBufLength, s, len);
      syslogBufLength += len;
      syslogBuf[syslogBufLength] = '\0';
  
      maybeFlushSyslog(type);
  }
  
  #else
  static void
  initSyslog()
  {
      return;
  }
  #endif
  
  /* Flush any messages waiting to be logged. */
  void flushLog()
  {
      if(logF)
          fflush(logF);
  
  #ifdef HAVE_SYSLOG
      /* There shouldn't really be anything here, but let's be paranoid.
         We can't pick a good value for `type', so just invent one. */
      if(logSyslog && syslogBuf[0] != '\0') {
          accumulateSyslogN(L_INFO, "\n", 1);
      }
  
      assert(syslogBufLength == 0);
  #endif
  }
  
  void
  reopenLog()
  {
      if(logFile) {
          FILE *f;
          f = fopen(logFile->string, "a");
          if(f == NULL) {
              do_log_error(L_ERROR, errno, "Couldn't reopen log file %s",
                           logFile->string);
              exit(1);
          }
          setvbuf(f, NULL, _IOLBF, 0);
          fclose(logF);
          logF = f;
      }
  
      if(logSyslog) {
          initSyslog();
      }
  }
  
  void
  really_do_log(int type, const char *f, ...)
  {
      va_list args;
  
      va_start(args, f);
      if(type & LOGGING_MAX & logLevel)
          really_do_log_v(type, f, args);
      va_end(args);
  }
  
  void
  really_do_log_v(int type, const char *f, va_list args)
  {
      if(type & LOGGING_MAX & logLevel) {
          if(logF){
              time_t ti = time(NULL);
              char *logtime = ctime(&ti);
              size_t newlen = strlen(logtime) + strlen(f);
              char *newf = (char *)malloc(newlen+3);
              newf[0] = '[';
              strcpy(newf+1,logtime);
              newf[1+strlen(logtime)-1] = ']';
              strcat(newf,f);
              
              vfprintf(logF, newf, args);
  
              free(newf);
          }
  #ifdef HAVE_SYSLOG
          if(logSyslog)
              accumulateSyslogV(type, f, args);
  #endif
      }
  }
  
  void
  really_do_log_error(int type, int e, const char *f, ...)
  {
      va_list args;
      va_start(args, f);
      if(type & LOGGING_MAX & logLevel)
          really_do_log_error_v(type, e, f, args);
      va_end(args);
  }
  
  void
  really_do_log_error_v(int type, int e, const char *f, va_list args)
  {
      if((type & LOGGING_MAX & logLevel) != 0) {
          char *es = pstrerror(e);
          if(es == NULL)
              es = "Unknown error";
  
          if(logF) {
              time_t ti = time(NULL);
              char *logtime = ctime(&ti);
              size_t newlen = strlen(logtime) + strlen(f);
              char *newf = (char *)malloc(newlen+3);
              newf[0] = '[';
              strcpy(newf+1,logtime);
              newf[1+strlen(logtime)-1] = ']';
              strcat(newf,f);
      
              vfprintf(logF, newf, args);
              fprintf(logF, ": %s\n", es);
              
              free(newf);            
          }
  #ifdef HAVE_SYSLOG
          if(logSyslog) {
              char msg[256];
              size_t n = 0;
  
              n = snnvprintf(msg, n, 256, f, args);
              n = snnprintf(msg, n, 256, ": ");
              n = snnprint_n(msg, n, 256, es, strlen (es));
              n = snnprintf(msg, n, 256, "\n");
              /* Overflow? Vanishingly unlikely; truncate at 255. */
              if(n < 0 || n > 256) {
                  n = 256;
                  msg[255] = '\0';
              }
              else
                  msg[n] = '\0';
  
              accumulateSyslogN(type, msg, n);
          }
  #endif
      }
  }
  
  void
  really_do_log_n(int type, const char *s, int n)
  {
      if((type & LOGGING_MAX & logLevel) != 0) {
          if(logF) {
              fwrite(s, n, 1, logF);
          }
  #ifdef HAVE_SYSLOG
          if(logSyslog)
              accumulateSyslogN(type, s, n);
  #endif
      }
  }
  