>From 701ba942339ab3c56b361891496cda6bd2fdbd71 Mon Sep 17 00:00:00 2001 From: Richard W.M. Jones Date: Thu, 27 Jan 2011 17:27:41 +0000 Subject: [PATCH 1/5] daemon: Replace root_mounted global with intelligence. We used to maintain a global flag 'root_mounted' which tells us if the user has mounted something on root (ie. on the sysroot directory). This flag caused a lot of trouble (eg. RHBZ#599503) because it's hard to keep the flag updated correctly when the user can do arbitrary mounts and also use mkmountpoint. Remove this flag and replace it with a test to see if something is mounted on *or under* the sysroot. (It has to be *or under* because of mkmountpoint and friends). This also replaces a rather convoluted "have we mounted root yet" check in the mount* APIs with a simpler check to see if the mountpoint exists and is an ordinary directory. --- daemon/daemon.h | 4 +- daemon/mount.c | 74 ++++++++++++++++++++++++++++++++++++------------------ 2 files changed, 51 insertions(+), 27 deletions(-) diff --git a/daemon/daemon.h b/daemon/daemon.h index 6845e1b..da991b1 100644 --- a/daemon/daemon.h +++ b/daemon/daemon.h @@ -107,7 +107,7 @@ extern uint64_t progress_hint; extern uint64_t optargs_bitmask; /*-- in mount.c --*/ -extern int root_mounted; +extern int is_root_mounted (void); /*-- in stubs.c (auto-generated) --*/ extern void dispatch_incoming_message (XDR *); @@ -178,7 +178,7 @@ extern void notify_progress (uint64_t position, uint64_t total); */ #define NEED_ROOT(cancel_stmt,fail_stmt) \ do { \ - if (!root_mounted) { \ + if (!is_root_mounted ()) { \ if ((cancel_stmt) != -2) \ reply_with_error ("%s: you must call 'mount' first to mount the root filesystem", __func__); \ fail_stmt; \ diff --git a/daemon/mount.c b/daemon/mount.c index ccd07c6..c584f81 100644 --- a/daemon/mount.c +++ b/daemon/mount.c @@ -24,12 +24,43 @@ #include #include #include +#include #include "daemon.h" #include "actions.h" -/* You must mount something on "/" first, hence: */ -int root_mounted = 0; +/* You must mount something on "/" first before many operations. + * Hence we have an internal function which can test if something is + * mounted on *or under* the sysroot directory. (It has to be *or + * under* because of mkmountpoint and friends). + */ +int +is_root_mounted (void) +{ + FILE *fp; + struct mntent *m; + + fp = setmntent ("/etc/mtab", "r"); + if (fp == NULL) { + perror ("/etc/mtab"); + exit (EXIT_FAILURE); + } + + while ((m = getmntent (fp)) != NULL) { + /* Allow a mount directory like "/sysroot". */ + if (sysroot_len > 0 && STREQ (m->mnt_dir, sysroot)) { + gotit: + endmntent (fp); + return 1; + } + /* Or allow a mount directory like "/sysroot/...". */ + if (STRPREFIX (m->mnt_dir, sysroot) && m->mnt_dir[sysroot_len] == '/') + goto gotit; + } + + endmntent (fp); + return 0; +} /* The "simple mount" call offers no complex options, you can just * mount a device on a mountpoint. The variations like mount_ro, @@ -44,25 +75,31 @@ int do_mount_vfs (const char *options, const char *vfstype, const char *device, const char *mountpoint) { - int r, is_root; + int r; char *mp; char *error; + struct stat statbuf; ABS_PATH (mountpoint, 0, return -1); - is_root = STREQ (mountpoint, "/"); - - if (!root_mounted && !is_root) { - reply_with_error ("you must mount something on / first"); - return -1; - } - mp = sysroot_path (mountpoint); if (!mp) { reply_with_perror ("malloc"); return -1; } + /* Check the mountpoint exists and is a directory. */ + if (stat (mp, &statbuf) == -1) { + reply_with_perror ("mount: %s", mountpoint); + free (mp); + return -1; + } + if (!S_ISDIR (statbuf.st_mode)) { + reply_with_perror ("mount: %s: mount point is not a directory", mountpoint); + free (mp); + return -1; + } + if (vfstype) r = command (NULL, &error, "mount", "-o", options, "-t", vfstype, device, mp, NULL); @@ -76,9 +113,6 @@ do_mount_vfs (const char *options, const char *vfstype, return -1; } - if (is_root) - root_mounted = 1; - return 0; } @@ -134,8 +168,6 @@ do_umount (const char *pathordevice) free (err); - /* update root_mounted? */ - return 0; } @@ -324,9 +356,6 @@ do_umount_all (void) free_stringslen (mounts, size); - /* We've unmounted root now, so ... */ - root_mounted = 0; - return 0; } @@ -368,8 +397,8 @@ do_mount_loop (const char *file, const char *mountpoint) } /* Specialized calls mkmountpoint and rmmountpoint are really - * variations on mkdir and rmdir which do no checking and (in the - * mkmountpoint case) set the root_mounted flag. + * variations on mkdir and rmdir which do no checking of the + * is_root_mounted() flag. */ int do_mkmountpoint (const char *path) @@ -388,11 +417,6 @@ do_mkmountpoint (const char *path) return -1; } - /* Set the flag so that filesystems can be mounted here, - * not just on /sysroot. - */ - root_mounted = 1; - return 0; } -- 1.7.3.5