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/* $Id: utils.c,v 1.8 2001-08-30 16:52:56 rjkaes Exp $ * * Misc. routines which are used by the various functions to handle strings * and memory allocation and pretty much anything else we can think of. Also, * the load cutoff routine is in here. Could not think of a better place for * it, so it's in here. * * Copyright (C) 1998 Steven Young * Copyright (C) 1999 Robert James Kaes (rjkaes@flarenet.com) * * This program is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License as published by the * Free Software Foundation; either version 2, or (at your option) any * later version. * * This program is distributed in the hope that it will be useful, but * WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * General Public License for more details. */ #include "tinyproxy.h" #include #include #include #include "buffer.h" #include "log.h" #include "sock.h" #include "utils.h" /* * Display an error to the client. */ #define HEADER_SIZE (1024 * 8) int httperr(struct conn_s *connptr, int err, const char *msg) { static char *headers = \ "HTTP/1.0 %d %s\r\n" \ "Server: %s/%s\r\n" \ "Date: %s\r\n" \ "Content-Type: text/html\r\n" \ "Content-Length: %d\r\n" \ "Connection: close\r\n" \ "\r\n"; static char *message = \ "%s\r\n" \ "\r\n" \ "Cache Error!
\r\n" \ "An error of type %d occurred: %s\r\n" \ "

\r\n" \ "Generated by %s (%s)\r\n" \ "\r\n\r\n"; char *header_buffer; char *message_buffer; int output_size; char timebuf[30]; time_t global_time; header_buffer = malloc(HEADER_SIZE); if (!header_buffer) { log_message(LOG_CRIT, "Out of memory!"); return -1; } message_buffer = malloc(MAXBUFFSIZE); if (!message_buffer) { log_message(LOG_CRIT, "Out of memory!"); safefree(header_buffer); return -1; } global_time = time(NULL); strftime(timebuf, sizeof(timebuf), "%a, %d %b %Y %H:%M:%S GMT", gmtime(&global_time)); snprintf(message_buffer, MAXBUFFSIZE - 1, message, msg, err, msg, PACKAGE, VERSION); snprintf(header_buffer, HEADER_SIZE - 1, headers, err, msg, PACKAGE, VERSION, timebuf, strlen(message_buffer)); output_size = strlen(message_buffer) + strlen(header_buffer); connptr->output_message = malloc(output_size + 1); if (!connptr->output_message) { log_message(LOG_CRIT, "Out of memory!"); safefree(header_buffer); safefree(message_buffer); return -1; } strlcpy(connptr->output_message, header_buffer, output_size); strlcat(connptr->output_message, message_buffer, output_size); safefree(header_buffer); safefree(message_buffer); return 0; } void makedaemon(void) { if (fork() != 0) exit(0); setsid(); signal(SIGHUP, SIG_IGN); if (fork() != 0) exit(0); chdir("/"); umask(077); close(0); close(1); close(2); } /* * Safely creates filename and returns the low-level file descriptor. */ static int create_file_safely(const char *filename) { struct stat lstatinfo; int fildes; /* * lstat() the file. If it doesn't exist, create it with O_EXCL. * If it does exist, open it for writing and perform the fstat() * check. */ if (lstat(filename, &lstatinfo) < 0) { /* * If lstat() failed for any reason other than "file not * existing", exit. */ if (errno != ENOENT) { log_message(LOG_ERR, "Error checking PID file %s: %s", filename, strerror(errno)); return -1; } /* * The file doesn't exist, so create it with O_EXCL to make * sure an attacker can't slip in a file between the lstat() * and open() */ if ((fildes = open(filename, O_RDWR | O_CREAT | O_EXCL, 0600)) < 0) { log_message(LOG_ERR, "Could not create PID file %s: %s", filename, strerror(errno)); return -1; } } else { struct stat fstatinfo; /* * Open an existing file. */ if ((fildes = open(filename, O_RDWR)) < 0) { log_message(LOG_ERR, "Could not open PID file %s: %s", filename, strerror(errno)); return -1; } /* * fstat() the opened file and check that the file mode bits, * inode, and device match. */ if (fstat(fildes, &fstatinfo) < 0 || lstatinfo.st_mode != fstatinfo.st_mode || lstatinfo.st_ino != fstatinfo.st_ino || lstatinfo.st_dev != fstatinfo.st_dev) { log_message(LOG_ERR, "The PID file %s has been changed before it could be opened!", filename); close(fildes); return -1; } /* * If the above check was passed, we know that the lstat() * and fstat() were done on the same file. Now we check that * there's only one link, and that it's a normal file (this * isn't strictly necessary because the fstat() vs lstat() * st_mode check would also find this) */ if (fstatinfo.st_nlink > 1 || !S_ISREG(lstatinfo.st_mode)) { log_message(LOG_ERR, "The PID file %s has too many links, or is not a regular file: %s", filename, strerror(errno)); close(fildes); return -1; } /* * On systems whcih don't support ftruncate() the best we can * do is to close the file and reopen it in create mode, which * unfortunately leads to a race condition, however "systems * which don't support ftruncate()" is pretty much SCO only, * and if you're using that you deserve what you get. * ("Little sympathy has been extended") */ #ifdef HAVE_FTRUNCATE ftruncate(fildes, 0); #else close(fildes); if ((fildes = open(filename, O_RDWR | O_CREAT | O_TRUNC, 0600)) < 0) { log_message(LOG_ERR, "Could not open PID file %s: %s", filename, strerror(errno)); return -1; } #endif /* HAVE_FTRUNCATE */ } return fildes; } /* * Write the PID of the program to the specified file. */ void pidfile_create(const char *filename) { int fildes; FILE *fd; /* * Create a new file */ if ((fildes = create_file_safely(filename)) < 0) exit(1); /* * Open a stdio file over the low-level one. */ if ((fd = fdopen(fildes, "w")) == NULL) { log_message(LOG_ERR, "fdopen() error on PID file %s: %s", filename, strerror(errno)); close(fildes); unlink(filename); exit(1); } fprintf(fd, "%ld\n", (long)getpid()); fclose(fd); } #ifndef HAVE_STRLCPY /* * Function API taken from OpenBSD. Like strncpy(), but does not 0 fill the * buffer, and always NULL terminates the buffer. size is the size of the * destination buffer. */ size_t strlcpy(char *dst, const char *src, size_t size) { size_t len = strlen(src); size_t ret = len; if (len >= size) len = size - 1; memcpy(dst, src, len); dst[len] = '\0'; return ret; } #endif #ifndef HAVE_STRLCAT /* * Function API taken from OpenBSD. Like strncat(), but does not 0 fill the * buffer, and always NULL terminates the buffer. size is the length of the * buffer, which should be one more than the maximum resulting string * length. */ size_t strlcat(char *dst, const char *src, size_t size) { size_t len1 = strlen(dst); size_t len2 = strlen(src); size_t ret = len1 + len2; if (len1 + len2 >= size) len2 = size - len1 - 1; if (len2 > 0) { memcpy(dst + len1, src, len2); dst[len1 + len2] = '\0'; } return ret; } #endif