From 5edec024b1ed7bbdf73095791c13df324038c31d Mon Sep 17 00:00:00 2001 From: Matthias Schwarzott Date: Tue, 13 Mar 2007 22:27:21 +0100 Subject: [PATCH] udevd: cleanup std{in,our,err} on startup It occurs, when root-partition has no /dev/console, meaning that kernel could not open it, and such udevd is started without open filedescriptors 0 1 2. In that case udevd openes its sockets (netlink and control). They get fds between 0 and 2. Later duping /dev/null to 0 1 2 closes the sockets and replaces them with /dev/null. The error condition can also be reproduced by starting udevd with this command-line: udevd --daemon <&- >&- 2>&- --- udevd.c | 30 +++++++++++++++++++----------- 1 file changed, 19 insertions(+), 11 deletions(-) diff --git a/udevd.c b/udevd.c index 23f5fd698..961ceb587 100644 --- a/udevd.c +++ b/udevd.c @@ -989,6 +989,19 @@ int main(int argc, char *argv[], char *envp[]) goto exit; } + /* make sure std{in,out,err} fd's are in a sane state */ + fd = open("/dev/null", O_RDWR); + if (fd < 0) { + fprintf(stderr, "cannot open /dev/null\n"); + err("cannot open /dev/null"); + } + if (fd > STDIN_FILENO) + dup2(fd, STDIN_FILENO); + if (write(STDOUT_FILENO, 0, 0) < 0) + dup2(fd, STDOUT_FILENO); + if (write(STDERR_FILENO, 0, 0) < 0) + dup2(fd, STDERR_FILENO); + /* init sockets to receive events */ if (init_udevd_socket() < 0) { if (errno == EADDRINUSE) { @@ -1064,17 +1077,12 @@ int main(int argc, char *argv[], char *envp[]) } } - /* redirect std fd's */ - fd = open("/dev/null", O_RDWR); - if (fd >= 0) { - dup2(fd, STDIN_FILENO); - if (!verbose) - dup2(fd, STDOUT_FILENO); - dup2(fd, STDERR_FILENO); - if (fd > STDERR_FILENO) - close(fd); - } else - err("error opening /dev/null: %s", strerror(errno)); + /* redirect std{out,err} fd's */ + if (!verbose) + dup2(fd, STDOUT_FILENO); + dup2(fd, STDERR_FILENO); + if (fd > STDERR_FILENO) + close(fd); /* set scheduling priority for the daemon */ setpriority(PRIO_PROCESS, 0, UDEVD_PRIORITY); -- 2.30.2