[CRIU] [PATCH] Use *open_proc* where possible

[Andrei Vagin]

On Tue, Mar 28, 2017 at 06:10:34PM -0700, Kir Kolyshkin wrote:
> Using open_proc/fopen_proc/__open_proc is better since
>  - it uses openat
>  - it comes with nice error reporting
> 
> Let's use it in places where we can. Even if it does not give any
> improvements (such as in cr-check.c), error message unification
> is good enough reason to do so.
> 
> Requested-by: Pavel Emelyanov <xemul at virtuozzo.com>
> Signed-off-by: Kir Kolyshkin <kir at openvz.org>
> ---
>  criu/autofs.c     |  6 ++----
>  criu/cr-check.c   | 12 ++++--------
>  criu/kerndat.c    |  9 +++------
>  criu/namespaces.c | 14 ++++----------
>  criu/net.c        |  6 ++----
>  5 files changed, 15 insertions(+), 32 deletions(-)
> 
> diff --git a/criu/autofs.c b/criu/autofs.c
> index a436e9f..15b0fc4 100644
> --- a/criu/autofs.c
> +++ b/criu/autofs.c
> @@ -359,11 +359,9 @@ static int access_autofs_mount(struct mount_info *pm)
>  	if (new_pid_ns < 0)
>  		return -1;
>  
> -	old_pid_ns = open("/proc/self/ns/pid", O_RDONLY);
> -	if (old_pid_ns < 0) {
> -		pr_perror("Can't open /proc/self/ns/pid");
> +	old_pid_ns = open_proc(PROC_SELF, "ns/pid");
> +	if (old_pid_ns < 0)
>  		goto close_new_pid_ns;
> -	}
>  
>  	if (switch_ns(pm->nsid->ns_pid, &mnt_ns_desc, &old_mnt_ns)) {
>  		pr_err("failed to switch to mount namespace\n");
> diff --git a/criu/cr-check.c b/criu/cr-check.c
> index 176eafb..28e8db1 100644
> --- a/criu/cr-check.c
> +++ b/criu/cr-check.c
> @@ -245,11 +245,9 @@ static int check_fcntl(void)
>  	u32 v[2];
>  	int fd;
>  
> -	fd = open("/proc/self/comm", O_RDONLY);
> -	if (fd < 0) {
> -		pr_perror("Can't open self comm file");
> +	fd = open_proc(PROC_SELF, "comm");
> +	if (fd < 0)
>  		return -1;
> -	}
>  
>  	if (fcntl(fd, F_GETOWNER_UIDS, (long)v)) {
>  		pr_perror("Can'r fetch file owner UIDs");
> @@ -727,11 +725,9 @@ static unsigned long get_ring_len(unsigned long addr)
>  	FILE *maps;
>  	char buf[256];
>  
> -	maps = fopen("/proc/self/maps", "r");
> -	if (!maps) {
> -		pr_perror("No maps proc file");
> +	maps = fopen_proc(PROC_SELF, "maps");
> +	if (!maps)
>  		return 0;
> -	}
>  
>  	while (fgets(buf, sizeof(buf), maps)) {
>  		unsigned long start, end;
> diff --git a/criu/kerndat.c b/criu/kerndat.c
> index 354c2a5..22dd1e8 100644
> --- a/criu/kerndat.c
> +++ b/criu/kerndat.c
> @@ -297,9 +297,8 @@ int kerndat_get_dirty_track(void)
>  		goto no_dt;
>  
>  	ret = -1;
> -	pm2 = open("/proc/self/pagemap", O_RDONLY);
> +	pm2 = open_proc(PROC_SELF, "pagemap");
>  	if (pm2 < 0) {
> -		pr_perror("Can't open pagemap file");
>  		munmap(map, PAGE_SIZE);
>  		return ret;
>  	}
> @@ -400,11 +399,9 @@ int kerndat_fdinfo_has_lock()
>  	int fd, pfd = -1, exit_code = -1, len;
>  	char buf[PAGE_SIZE];
>  
> -	fd = open("/proc/locks", O_RDONLY);
> -	if (fd < 0) {
> -		pr_perror("Unable to open /proc/locks");
> +	fd = open_proc(PROC_GEN, "locks");
> +	if (fd < 0)
>  		return -1;
> -	}
>  
>  	if (flock(fd, LOCK_SH)) {
>  		pr_perror("Can't take a lock");
> diff --git a/criu/namespaces.c b/criu/namespaces.c
> index c1bee49..02959e7 100644
> --- a/criu/namespaces.c
> +++ b/criu/namespaces.c
> @@ -241,16 +241,12 @@ int switch_ns(int pid, struct ns_desc *nd, int *rst)
>  
>  int switch_ns_by_fd(int nsfd, struct ns_desc *nd, int *rst)
>  {
> -	char buf[32];
>  	int ret = -1;
>  
>  	if (rst) {
> -		snprintf(buf, sizeof(buf), "/proc/self/ns/%s", nd->str);
> -		*rst = open(buf, O_RDONLY);
> -		if (*rst < 0) {
> -			pr_perror("Can't open ns file");
> +		*rst = open_proc(PROC_SELF, "ns/%s", nd->str);
> +		if (*rst < 0)
>  			goto err_ns;
> -		}
>  	}
>  
>  	ret = setns(nsfd, nd->cflag);
> @@ -2194,11 +2190,9 @@ static int create_user_ns_hierarhy_fn(void *in_arg)
>  		/* Set self pid to allow parent restore user_ns maps */
>  		p_arg->pid = get_self_real_pid();
>  		futex_set_and_wake(p_futex, NS__CREATED);
> -		fd = open("/proc/self/ns/user", O_RDONLY);
> -		if (fd < 0) {
> -			pr_perror("Can't get self user ns");
> +		fd = open_proc(PROC_SELF, "ns/user");
> +		if (fd < 0)

https://ci.openvz.org/view/CRIU/job/CRIU/job/CRIU-snap/job/criu-dev/2079/consoleFull

------------------------ grep Error ------------------------
(00.271276)      1: Error (criu/util.c:204): fd 0 already in use (called
at criu/files.c:1008)
(00.292162) Error (criu/cr-restore.c:1127): 425 exited, status=1
(00.295802) Error (criu/cr-restore.c:2059): Restoring FAILED.
------------------------ ERROR OVER ------------------------

>  			goto out;
> -		}
>  		me->user.nsfd_id = fdstore_add(fd);
>  		close(fd);
>  		if (me->user.nsfd_id < 0) {
> diff --git a/criu/net.c b/criu/net.c
> index e06d32b..b423000 100644
> --- a/criu/net.c
> +++ b/criu/net.c
> @@ -2210,11 +2210,9 @@ int netns_keep_nsfd(void)
>  	 * that before we leave the existing namespaces.
>  	 */
>  
> -	ns_fd = open("/proc/self/ns/net", O_RDONLY | O_CLOEXEC);
> -	if (ns_fd < 0) {
> -		pr_perror("Can't cache net fd");
> +	ns_fd = __open_proc(PROC_SELF, 0, O_RDONLY | O_CLOEXEC, "ns/net");
> +	if (ns_fd < 0)
>  		return -1;
> -	}
>  
>  	ret = install_service_fd(NS_FD_OFF, ns_fd);
>  	if (ret < 0)
> -- 
> 2.9.3
>