Different way of mounting things

diff --git a/mount.c b/mount.c
index cd1fe4d79b412b4166703f8a4fe04af9c82f8658..b8fb0fe78c11800ce6336855a92187bb6cf04288 100644 (file)
--- a/mount.c
+++ b/mount.c
@@ -41,9 +41,9 @@
 static bool mountIsDir(const char *path)
 {
        /*
-        *  If the source dir is NULL, we assume it's a dir (for /proc and tmpfs)
+        *  If the source dir is empty, we assume it's a dir (for /proc and tmpfs)
         */
-       if (path == NULL) {
+       if (strcmp(path, "") == 0) {
                return true;
        }
        struct stat st;
@@ -61,7 +61,7 @@ static bool mountIsDir(const char *path)
 // stat() failure
 static bool mountNotIsDir(const char *path)
 {
-       if (path == NULL) {
+       if (strcmp(path, "") == 0) {
                return false;
        }
        struct stat st;
@@ -75,18 +75,26 @@ static bool mountNotIsDir(const char *path)
        return true;
 }
 
-static bool mountMount(struct nsjconf_t *nsjconf, struct mounts_t *mpt, const char *dst)
+static bool mountMount(struct nsjconf_t *nsjconf, struct mounts_t *mpt, const char *oldroot,
+                      const char *dst)
 {
        LOG_D("Mounting '%s' on '%s' (type:'%s', flags:0x%tx, options:'%s')", mpt->src, dst,
              mpt->fs_type, mpt->flags, mpt->options);
 
-       if (mountIsDir(mpt->src) == true) {
+       char src[PATH_MAX];
+       if (mpt->src == NULL) {
+               src[0] = '\0';
+       } else {
+               snprintf(src, sizeof(src), "%s/%s", oldroot, mpt->src);
+       }
+
+       if (mountIsDir(src) == true) {
                if (mkdir(dst, 0711) == -1 && errno != EEXIST) {
                        PLOG_W("mkdir('%s')", dst);
                }
        }
 
-       if (mountNotIsDir(mpt->src) == true) {
+       if (mountNotIsDir(src) == true) {
                int fd = TEMP_FAILURE_RETRY(open(dst, O_CREAT | O_RDONLY, 0644));
                if (fd >= 0) {
                        close(fd);
@@ -99,13 +107,13 @@ static bool mountMount(struct nsjconf_t *nsjconf, struct mounts_t *mpt, const ch
         * Initially mount it as RW, it will be remounted later on if needed
         */
        unsigned long flags = mpt->flags & ~(MS_RDONLY);
-       if (mount(mpt->src, dst, mpt->fs_type, flags, mpt->options) == -1) {
+       if (mount(src, dst, mpt->fs_type, flags, mpt->options) == -1) {
                if (errno == EACCES) {
                        PLOG_E
                            ("mount('%s', '%s', type='%s') failed. Try fixing this problem by applying 'chmod o+x' to the '%s' directory and its ancestors",
-                            mpt->src, dst, mpt->fs_type, nsjconf->chroot);
+                            src, dst, mpt->fs_type, nsjconf->chroot);
                } else {
-                       PLOG_E("mount('%s', '%s', type='%s') failed", mpt->src, dst, mpt->fs_type);
+                       PLOG_E("mount('%s', '%s', type='%s') failed", src, dst, mpt->fs_type);
                }
                return false;
        }
@@ -158,8 +166,22 @@ static bool mountInitNsInternal(struct nsjconf_t *nsjconf)
                PLOG_E("mount('%s', 'tmpfs'", destdir);
                return false;
        }
-       char newrootdir[PATH_MAX];
-       snprintf(newrootdir, sizeof(newrootdir), "%s/%s", destdir, "new_root");
+       char oldrootdir[PATH_MAX];
+       snprintf(oldrootdir, sizeof(oldrootdir), "%s/oldroot", destdir);
+       if (mkdir(oldrootdir, 0755) == -1) {
+               PLOG_E("mkdir('%s')", oldrootdir);
+               return false;
+       }
+       if (syscall(__NR_pivot_root, destdir, oldrootdir) == -1) {
+               PLOG_E("pivot_root('%s', '%s')", destdir, oldrootdir);
+               return false;
+       }
+       if (chdir("/") == -1) {
+               PLOG_E("chroot('/')");
+               return false;
+       }
+
+       const char *const newrootdir = "/new_root";
        if (mkdir(newrootdir, 0755) == -1) {
                PLOG_E("mkdir('%s')", newrootdir);
                return false;
@@ -169,22 +191,12 @@ static bool mountInitNsInternal(struct nsjconf_t *nsjconf)
        TAILQ_FOREACH(p, &nsjconf->mountpts, pointers) {
                char dst[PATH_MAX];
                snprintf(dst, sizeof(dst), "%s/%s", newrootdir, p->dst);
-               if (mountMount(nsjconf, p, dst) == false) {
+               if (mountMount(nsjconf, p, "/oldroot", dst) == false) {
                        return false;
                }
        }
 
-       char pivotrootdir[PATH_MAX];
-       snprintf(pivotrootdir, sizeof(pivotrootdir), "%s/%s", destdir, "pivot_root");
-       if (mkdir(pivotrootdir, 0755) == -1) {
-               PLOG_E("mkdir('%s')", pivotrootdir);
-               return false;
-       }
-       if (syscall(__NR_pivot_root, destdir, pivotrootdir) == -1) {
-               PLOG_E("pivot_root('%s', '%s')", destdir, pivotrootdir);
-               return false;
-       }
-       if (umount2("/pivot_root", MNT_DETACH) == -1) {
+       if (umount2("/oldroot", MNT_DETACH) == -1) {
                PLOG_E("umount2('/pivot_root', MNT_DETACH)");
                return false;
        }
@@ -204,15 +216,6 @@ static bool mountInitNsInternal(struct nsjconf_t *nsjconf)
                }
        }
 
-       /*
-        * Remove the tmpfs from /tmp is we are mounting / as root
-        */
-       if (0 == strcmp(nsjconf->chroot, "/")) {
-               if (umount2(destdir, MNT_DETACH) == -1) {
-                       PLOG_W("umount2('%s', MNT_DETACH) failed", destdir);
-               }
-       }
-
        return true;
 }