proc_parse: parse fdinfo to get pos and flags

We are going to parse fdinfo for getting mnt_id,
so we can take there pos and flags and don't call
fcntl and lseek for that.
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

files.c

@@ -34,6 +34,7 @@
 #include "tun.h"
 #include "fdset.h"
 #include "fs-magic.h"
+#include "proc_parse.h"
 
 #include "parasite.h"
 #include "parasite-syscall.h"
@@ -204,6 +205,7 @@ static int fill_fd_params(struct parasite_ctl *ctl, int fd, int lfd,
 {
 	int ret;
 	struct statfs fsbuf;
+	struct fdinfo_common fdinfo;
 
 	if (fstat(lfd, &p->stat) < 0) {
 		pr_perror("Can't stat fd %d", lfd);
@@ -215,16 +217,14 @@ static int fill_fd_params(struct parasite_ctl *ctl, int fd, int lfd,
 		return -1;
 	}
 
+	if (parse_fdinfo(lfd, FD_TYPES__UND, NULL, &fdinfo))
+		return -1;
+
 	p->fs_type	= fsbuf.f_type;
 	p->ctl		= ctl;
 	p->fd		= fd;
-	p->pos		= lseek(lfd, 0, SEEK_CUR);
-	ret = fcntl(lfd, F_GETFL);
-	if (ret == -1) {
-		pr_perror("Unable to get fd %d flags", lfd);
-		return -1;
-	}
-	p->flags	= ret;
+	p->pos		= fdinfo.pos;
+	p->flags	= fdinfo.flags;
 	p->pid		= ctl->pid.real;
 	p->fd_flags	= opts->flags;
 

include/proc_parse.h

@@ -153,6 +153,11 @@ union fdinfo_entries {
 	FanotifyMarkEntry ffy;
 };
 
+struct fdinfo_common {
+	off64_t pos;
+	int flags;
+};
+
 extern int parse_fdinfo(int fd, int type,
 		int (*cb)(union fdinfo_entries *e, void *arg), void *arg);
 extern int parse_fdinfo_pid(int pid, int fd, int type,

proc_parse.c

@@ -1020,7 +1020,27 @@ static int parse_fdinfo_pid_s(char *pid, int fd, int type,
 	while (fgets(str, sizeof(str), f)) {
 		union fdinfo_entries entry;
 
-		if (fdinfo_field(str, "pos") || fdinfo_field(str, "counter"))
+		if (fdinfo_field(str, "pos") ||
+		    fdinfo_field(str, "flags")) {
+			unsigned long long val;
+			struct fdinfo_common *fdinfo = arg;
+
+			if (type != FD_TYPES__UND)
+				continue;
+			ret = sscanf(str, "%*s %lli", &val);
+			if (ret != 1)
+				goto parse_err;
+
+			if (fdinfo_field(str, "pos"))
+				fdinfo->pos = val;
+			else if (fdinfo_field(str, "flags"))
+				fdinfo->flags = val;
+
+			entry_met = true;
+			continue;
+		}
+
+		if (type == FD_TYPES__UND)
 			continue;
 
 		if (fdinfo_field(str, "eventfd-count")) {