diff options
Diffstat (limited to 'cmd/zed/zed_log.c')
| -rw-r--r-- | cmd/zed/zed_log.c | 95 |
1 files changed, 95 insertions, 0 deletions
diff --git a/cmd/zed/zed_log.c b/cmd/zed/zed_log.c index bc432bc21..2a787e357 100644 --- a/cmd/zed/zed_log.c +++ b/cmd/zed/zed_log.c @@ -25,6 +25,7 @@ */ #include <assert.h> +#include <errno.h> #include <stdarg.h> #include <stdio.h> #include <stdlib.h> @@ -40,6 +41,7 @@ static struct { unsigned do_syslog:1; int level; char id[ZED_LOG_MAX_ID_LEN]; + int pipe_fd[2]; } _ctx; void @@ -53,6 +55,8 @@ zed_log_init(const char *identity) } else { _ctx.id[0] = '\0'; } + _ctx.pipe_fd[0] = -1; + _ctx.pipe_fd[1] = -1; } void @@ -63,6 +67,97 @@ zed_log_fini() } } +/* + * Create pipe for communicating daemonization status between the parent and + * child processes across the double-fork(). + */ +void +zed_log_pipe_open(void) +{ + if ((_ctx.pipe_fd[0] != -1) || (_ctx.pipe_fd[1] != -1)) + zed_log_die("Invalid use of zed_log_pipe_open in PID %d", + (int) getpid()); + + if (pipe(_ctx.pipe_fd) < 0) + zed_log_die("Failed to create daemonize pipe in PID %d: %s", + (int) getpid(), strerror(errno)); +} + +/* + * Close the read-half of the daemonize pipe. + * This should be called by the child after fork()ing from the parent since + * the child will never read from this pipe. + */ +void +zed_log_pipe_close_reads(void) +{ + if (_ctx.pipe_fd[0] < 0) + zed_log_die( + "Invalid use of zed_log_pipe_close_reads in PID %d", + (int) getpid()); + + if (close(_ctx.pipe_fd[0]) < 0) + zed_log_die( + "Failed to close reads on daemonize pipe in PID %d: %s", + (int) getpid(), strerror(errno)); + + _ctx.pipe_fd[0] = -1; +} + +/* + * Close the write-half of the daemonize pipe. + * This should be called by the parent after fork()ing its child since the + * parent will never write to this pipe. + * This should also be called by the child once initialization is complete + * in order to signal the parent that it can safely exit. + */ +void +zed_log_pipe_close_writes(void) +{ + if (_ctx.pipe_fd[1] < 0) + zed_log_die( + "Invalid use of zed_log_pipe_close_writes in PID %d", + (int) getpid()); + + if (close(_ctx.pipe_fd[1]) < 0) + zed_log_die( + "Failed to close writes on daemonize pipe in PID %d: %s", + (int) getpid(), strerror(errno)); + + _ctx.pipe_fd[1] = -1; +} + +/* + * Block on reading from the daemonize pipe until signaled by the child + * (via zed_log_pipe_close_writes()) that initialization is complete. + * This should only be called by the parent while waiting to exit after + * fork()ing the child. + */ +void +zed_log_pipe_wait(void) +{ + ssize_t n; + char c; + + if (_ctx.pipe_fd[0] < 0) + zed_log_die("Invalid use of zed_log_pipe_wait in PID %d", + (int) getpid()); + + for (;;) { + n = read(_ctx.pipe_fd[0], &c, sizeof (c)); + if (n < 0) { + if (errno == EINTR) + continue; + zed_log_die( + "Failed to read from daemonize pipe in PID %d: %s", + (int) getpid(), strerror(errno)); + } + if (n == 0) { + break; + } + } +} + void zed_log_stderr_open(int level) { |