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      1 // Copyright (C) 2011 The Android Open Source Project
      2 //
      3 // This software is licensed under the terms of the GNU General Public
      4 // License version 2, as published by the Free Software Foundation, and
      5 // may be copied, distributed, and modified under those terms.
      6 //
      7 // This program is distributed in the hope that it will be useful,
      8 // but WITHOUT ANY WARRANTY; without even the implied warranty of
      9 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
     10 // GNU General Public License for more details.
     11 
     12 #include "android/log-rotate.h"
     13 #include "net/net.h"
     14 #include "slirp-android/libslirp.h"
     15 #include "sysemu/sysemu.h"
     16 
     17 #include <stdio.h>
     18 
     19 #ifdef _WIN32
     20 
     21 void qemu_log_rotation_init(void) {
     22     // Nothing to do on Win32 for now.
     23 }
     24 
     25 void qemu_log_rotation_poll(void) {
     26     // Nothing to do on Win32 for now.
     27 }
     28 
     29 #else // !_WIN32
     30 
     31 #include <sys/signal.h>
     32 
     33 static int rotate_logs_requested = 0;
     34 
     35 static void rotate_qemu_logs_handler(int signum) {
     36   rotate_logs_requested = 1;
     37 }
     38 
     39 void qemu_log_rotation_init(void) {
     40   // Install SIGUSR1 signal handler.
     41   struct sigaction act;
     42   sigfillset(&act.sa_mask);
     43   act.sa_flags = 0;
     44   act.sa_handler = rotate_qemu_logs_handler;
     45   if (sigaction(SIGUSR1, &act, NULL) == -1) {
     46     fprintf(stderr, "Failed to setup SIGUSR1 handler to clear Qemu logs\n");
     47     exit(-1);
     48   }
     49 }
     50 
     51 
     52 // Clears the passed qemu log when the rotate_logs_requested
     53 // is set. We need to clear the logs between the tasks that do not
     54 // require restarting Qemu.
     55 static FILE* rotate_log(FILE* old_log_fd, const char* filename) {
     56   FILE* new_log_fd = NULL;
     57   if (old_log_fd) {
     58     if (fclose(old_log_fd) == -1) {
     59       fprintf(stderr, "Cannot close old_log fd\n");
     60       exit(errno);
     61     }
     62   }
     63 
     64   if (!filename) {
     65     fprintf(stderr, "The log filename to be rotated is not provided");
     66     exit(-1);
     67   }
     68 
     69   new_log_fd = fopen(filename , "wb+");
     70   if (new_log_fd == NULL) {
     71     fprintf(stderr, "Cannot open the log file: %s for write.\n",
     72             filename);
     73     exit(1);
     74   }
     75 
     76   return new_log_fd;
     77 }
     78 
     79 
     80 void qemu_log_rotation_poll(void) {
     81     if (!rotate_logs_requested)
     82         return;
     83 
     84     FILE* new_dns_log_fd = rotate_log(get_slirp_dns_log_fd(),
     85                                       dns_log_filename);
     86     FILE* new_drop_log_fd = rotate_log(get_slirp_drop_log_fd(),
     87                                        drop_log_filename);
     88     slirp_dns_log_fd(new_dns_log_fd);
     89     slirp_drop_log_fd(new_drop_log_fd);
     90     rotate_logs_requested = 0;
     91 }
     92 
     93 #endif  // !_WIN32
     94