Messages in this thread Patch in this message | | | From | Jovi Zhangwei <> | Subject | [PATCH v2 23/29] ktap: add ring buffer reader(tools/ktap/kp_reader.c) | Date | Fri, 28 Mar 2014 10:45:18 -0400 |
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This is ktap ring buffer consumer, a thread poll content from '/sys/kernel/debug/ktap/trace_pipe_%pid' debugfs file.
Signed-off-by: Jovi Zhangwei <jovi.zhangwei@gmail.com> --- tools/ktap/kp_reader.c | 106 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 106 insertions(+) create mode 100644 tools/ktap/kp_reader.c
diff --git a/tools/ktap/kp_reader.c b/tools/ktap/kp_reader.c new file mode 100644 index 0000000..103940e --- /dev/null +++ b/tools/ktap/kp_reader.c @@ -0,0 +1,106 @@ +/* + * reader.c - ring buffer reader in userspace + * + * This file is part of ktap by Jovi Zhangwei. + * + * Copyright (C) 2012-2014 Jovi Zhangwei <jovi.zhangwei@gmail.com>. + * + * ktap is free software; you can redistribute it and/or modify it + * under the terms and conditions of the GNU General Public License, + * version 2, as published by the Free Software Foundation. + * + * ktap is distributed in the hope 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. + * + * You should have received a copy of the GNU General Public License along with + * this program; if not, write to the Free Software Foundation, Inc., + * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA. + */ + +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <unistd.h> +#include <sys/mman.h> +#include <sys/stat.h> +#include <sys/poll.h> +#include <sys/signal.h> +#include <fcntl.h> +#include <pthread.h> + +#define MAX_BUFLEN 131072 +#define PATH_MAX 128 + +#define handle_error(str) do { perror(str); exit(-1); } while(0) + +void sigfunc(int signo) +{ + /* should not not reach here */ +} + +static void block_sigint() +{ + sigset_t mask; + + sigemptyset(&mask); + sigaddset(&mask, SIGINT); + + pthread_sigmask(SIG_BLOCK, &mask, NULL); +} + +static void *reader_thread(void *data) +{ + char buf[MAX_BUFLEN]; + char filename[PATH_MAX]; + const char *output = data; + int failed = 0, fd, out_fd, len; + + block_sigint(); + + if (output) { + out_fd = open(output, O_CREAT | O_WRONLY | O_TRUNC, + S_IRUSR|S_IWUSR); + if (out_fd < 0) { + fprintf(stderr, "Cannot open output file %s\n", output); + return NULL; + } + } else + out_fd = 1; + + sprintf(filename, "/sys/kernel/debug/ktap/trace_pipe_%d", getpid()); + + open_again: + fd = open(filename, O_RDONLY); + if (fd < 0) { + usleep(10000); + + if (failed++ == 10) { + fprintf(stderr, "Cannot open file %s\n", filename); + return NULL; + } + goto open_again; + } + + while ((len = read(fd, buf, sizeof(buf))) > 0) + write(out_fd, buf, len); + + close(fd); + close(out_fd); + + return NULL; +} + +int kp_create_reader(const char *output) +{ + pthread_t reader; + + signal(SIGINT, sigfunc); + + if (pthread_create(&reader, NULL, reader_thread, (void *)output) < 0) + handle_error("pthread_create reader_thread failed\n"); + + return 0; +} + -- 1.8.1.4
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