lxccontainer: improve mod_rdep()

Signed-off-by: Christian Brauner <christian@brauner.io>
O_RDWR -> O_WRONLY | O_CREAT
Signed-off-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@canonical.com>

diff --git a/src/lxc/lxccontainer.c b/src/lxc/lxccontainer.c
index e456daf9f5de7b5ade3741fa7b74310c74fe6c07..8a2efc2032d05af6e954d51ddc84c0555a05ab09 100644 (file)
--- a/src/lxc/lxccontainer.c
+++ b/src/lxc/lxccontainer.c
@@ -2647,13 +2647,14 @@ WRAP_API_1(bool, lxcapi_save_config, const char *)
 
 static bool mod_rdep(struct lxc_container *c0, struct lxc_container *c, bool inc)
 {
+       __do_close int fd = -EBADF;
        FILE *f1;
        struct stat fbuf;
        void *buf = NULL;
        char *del = NULL;
        char path[PATH_MAX];
        char newpath[PATH_MAX];
-       int fd, ret, n = 0, v = 0;
+       int ret, n = 0, v = 0;
        bool bret = false;
        size_t len = 0, bytes = 0;
 
@@ -2704,37 +2705,27 @@ static bool mod_rdep(struct lxc_container *c0, struct lxc_container *c, bool inc
                /* Here we know that we have or can use an lxc-snapshot file
                 * using the new format. */
                if (inc) {
-                       f1 = fopen(path, "ae");
-                       if (!f1)
+                       fd = open(path, O_APPEND | O_WRONLY | O_CREAT | O_CLOEXEC);
+                       if (fd < 0)
                                goto out;
 
-                       if (fprintf(f1, "%s", newpath) < 0) {
+                       ret = lxc_write_nointr(fd, newpath, strlen(newpath));
+                       if (ret < 0) {
                                ERROR("Error writing new snapshots entry");
-                               ret = fclose(f1);
-                               if (ret != 0)
-                                       SYSERROR("Error writing to or closing snapshots file");
-                               goto out;
-                       }
-
-                       ret = fclose(f1);
-                       if (ret != 0) {
-                               SYSERROR("Error writing to or closing snapshots file");
                                goto out;
                        }
                } else if (!inc) {
-                       if ((fd = open(path, O_RDWR | O_CLOEXEC)) < 0)
+                       fd = open(path, O_RDWR | O_CLOEXEC);
+                       if (fd < 0)
                                goto out;
 
-                       if (fstat(fd, &fbuf) < 0) {
-                               close(fd);
+                       if (fstat(fd, &fbuf) < 0)
                                goto out;
-                       }
 
                        if (fbuf.st_size != 0) {
                                buf = lxc_strmmap(NULL, fbuf.st_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
                                if (buf == MAP_FAILED) {
                                        SYSERROR("Failed to create mapping %s", path);
-                                       close(fd);
                                        goto out;
                                }
 
@@ -2747,16 +2738,13 @@ static bool mod_rdep(struct lxc_container *c0, struct lxc_container *c, bool inc
                                lxc_strmunmap(buf, fbuf.st_size);
                                if (ftruncate(fd, fbuf.st_size - bytes) < 0) {
                                        SYSERROR("Failed to truncate file %s", path);
-                                       close(fd);
                                        goto out;
                                }
                        }
-
-                       close(fd);
                }
 
                /* If the lxc-snapshot file is empty, remove it. */
-               if (stat(path, &fbuf) < 0)
+               if (fstat(fd, &fbuf) < 0)
                        goto out;
 
                if (!fbuf.st_size) {