xiaoxiang781216 commented on code in PR #3090: URL: https://github.com/apache/nuttx-apps/pull/3090#discussion_r2136909216
########## system/syslogd/syslogd_main.c: ########## @@ -0,0 +1,291 @@ +/**************************************************************************** + * apps/system/syslogd/syslogd_main.c + * + * SPDX-License-Identifier: Apache-2.0 + * + * Licensed to the Apache Software Foundation (ASF) under one or more + * contributor license agreements. See the NOTICE file distributed with + * this work for asyslogditional information regarding copyright ownership. + * The ASF licenses this file to you under the Apache License, Version 2.0 + * (the "License"); you may not use this file except in compliance with the + * License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT + * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the + * License for the specific language governing permissions and limitations + * under the License. + * + ****************************************************************************/ + +/**************************************************************************** + * Included Files + ****************************************************************************/ + +#include <nuttx/config.h> + +#include <errno.h> +#include <fcntl.h> +#include <stdbool.h> +#include <stdint.h> +#include <stdio.h> +#include <stdlib.h> +#include <unistd.h> + +#include <getopt.h> + +#include <arpa/inet.h> +#include <netinet/in.h> +#include <sys/socket.h> + +#include <syslog.h> + +/**************************************************************************** + * Pre-processor Definitions + ****************************************************************************/ + +/* Program name */ + +#define g_syslogd CONFIG_SYSTEM_SYSLOGD_PROGNAME + +/* syslogd program version */ + +#define SYSLOGD_VERSION "0.0.0" + +/* Minimum buffer size check */ + +#if CONFIG_SYSTEM_SYSLOGD_ENTRYSIZE < 480 +#error "SYSTEM_SYSLOGD_ENTRYSIZE must be more than 480 to satisfy RFC 5424" +#endif + +/**************************************************************************** + * Private Data + ****************************************************************************/ + +bool g_debugmode = false; +bool g_background = true; +char g_buffer[CONFIG_SYSTEM_SYSLOGD_ENTRYSIZE]; + +/**************************************************************************** + * Private Functions + ****************************************************************************/ + +/**************************************************************************** + * Name: print_usage + ****************************************************************************/ + +static void print_usage(void) +{ + fprintf(stderr, "usage:\n"); + fprintf(stderr, " %s [-vdn]\n", g_syslogd); +} + +/**************************************************************************** + * Name: read_log + * + * Description: + * Read a single log (end indicated by a newline character) into `buf`. + ****************************************************************************/ + +static ssize_t read_log(int fd, char *buf, size_t n) +{ + ssize_t count = 0; + ssize_t bread; + + while (count < n) + { + bread = read(fd, buf, 1); + + /* Error occurred */ + + if (bread < 0) + { + return bread; + } + + /* End of stream reached */ + + if (bread == 0) + { + break; + } + + /* Newline character reached */ + + if (*buf == '\n') + { + /* Don't increment count so user 'skips' the '\n' character */ + + break; + } + + count += bread; /* Read one more byte */ + buf += bread; /* Move ahead one spot in the buffer */ + } + + return count; +} + +/**************************************************************************** + * Public Functions + ****************************************************************************/ + +int main(int argc, FAR char **argv) +{ + int fd; + int sock; + int err; + int c; + ssize_t bread; + ssize_t bsent; + struct sockaddr_in client; + + /* Parse command line options */ + + while ((c = getopt(argc, argv, ":vdn")) != -1) + { + switch (c) + { + case 'v': + + /* Print version and exit */ + + printf("%s " SYSLOGD_VERSION " (NuttX)\n", g_syslogd); + return EXIT_SUCCESS; + break; + + case 'd': + + /* Enable debug mode and stay in foreground */ + + g_debugmode = true; + g_background = false; + break; + + case 'n': + + /* Stay in foreground */ + + g_background = false; + break; + + case '?': + print_usage(); + exit(EXIT_FAILURE); + break; + } + } + + /* Once all arguments are parsed, fork here to run in the background. + * TODO: what's a good way to tell if NuttX platform has fork()? + */ + + if (g_background) + { + err = fork(); Review Comment: > I've resolved to just use fork (in this latest version), protected by `CONFIG_ARCH_HAVE_FORK`. Systems that can't support it will have to run it in the foreground or use `nsh`'s backgrounding `&`. > but even CONFIG_ARCH_HAVE_FORK enable, fork doesn't work as your expect, so please don't use this feature in the production if you have other method. > I resolved against `posix_spawn` because it would result in an infinite loop of the program re-spawning itself unless I ran the spawned child process with the `-n` flag, requiring me to modify the original `argv` table. yes, you need call memmove to erase `-n` from argv before posix_spawn self. > `fork()` seemed like a more elegant solution, and it works on a device even as small as the RP2040 seemingly quite well. to make fork work on NO-MMU device, the implementation on NuttX is very simple, and has many limitation. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. 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