Reduce the size of mount (and bypass /proc/filesystems) by using the sysfs

system call, based on work done by Glenn McGrath in December.
 -Erik

diff --git a/mount.c b/mount.c
index 76cab7d..2353a8a 100644 (file)
--- a/mount.c
+++ b/mount.c
@@ -83,6 +83,7 @@ extern int mount (__const char *__special_file, __const char *__dir,
                        __const void *__data);
 extern int umount (__const char *__special_file);
 extern int umount2 (__const char *__special_file, int __flags);
+static _syscall3(int, sysfs, int, option, unsigned int, fs_index, char *, buf);
 
 
 extern const char mtab_file[]; /* Defined in utility.c */
@@ -233,72 +234,24 @@ mount_one(char *blockDevice, char *directory, char *filesystemType,
 {
        int status = 0;
 
-       char buf[255];
        if (strcmp(filesystemType, "auto") == 0) {
-               FILE *f = xfopen("/proc/filesystems", "r");
-
-               while (fgets(buf, sizeof(buf), f) != NULL) {
-                       filesystemType = buf;
-                       if (*filesystemType == '\t') {  // Not a nodev filesystem
-
-                               // Add NULL termination to each line
-                               while (*filesystemType && *filesystemType != '\n')
-                                       filesystemType++;
-                               *filesystemType = '\0';
-
-                               filesystemType = buf;
-                               filesystemType++;       // hop past tab
-
-                               status = do_mount(blockDevice, directory, filesystemType,
-                                                                 flags | MS_MGC_VAL, string_flags,
-                                                                 useMtab, fakeIt, mtab_opts);
-                               if (status == TRUE)
-                                       break;
-                       }
-               }
-               fclose(f);
-       } else
-#if defined BB_FEATURE_USE_DEVPS_PATCH
-       if (strcmp(filesystemType, "auto") == 0) {
-               int fd, i, numfilesystems;
-               char device[] = "/dev/mtab";
-               struct k_fstype *fslist;
-
-               /* open device */ 
-               fd = open(device, O_RDONLY);
-               if (fd < 0)
-                       perror_msg_and_die("open failed for `%s'", device);
-
-               /* How many filesystems?  We need to know to allocate enough space */
-               numfilesystems = ioctl (fd, DEVMTAB_COUNT_FILESYSTEMS);
-               if (numfilesystems<0)
-                       perror_msg_and_die("\nDEVMTAB_COUNT_FILESYSTEMS");
-               fslist = (struct k_fstype *) xcalloc ( numfilesystems, sizeof(struct k_fstype));
-
-               /* Grab the list of available filesystems */
-               status = ioctl (fd, DEVMTAB_GET_FILESYSTEMS, fslist);
-               if (status<0)
-                       perror_msg_and_die("\nDEVMTAB_GET_FILESYSTEMS");
-
-               /* Walk the list trying to mount filesystems 
-                * that do not claim to be nodev filesystems */
-               for( i = 0 ; i < numfilesystems ; i++) {
-                       if (fslist[i].mnt_nodev)
-                               continue;
-                       status = do_mount(blockDevice, directory, fslist[i].mnt_type,
-                                                         flags | MS_MGC_VAL, string_flags,
-                                                         useMtab, fakeIt, mtab_opts);
+               int i=0;
+               const int num_of_filesystems = sysfs(3, 0, 0);
+               char buf[255];
+               filesystemType=buf;
+
+               while(i < num_of_filesystems) {
+                       sysfs(2, i++, filesystemType);
+                       status = do_mount(blockDevice, directory, filesystemType,
+                                       flags | MS_MGC_VAL, string_flags,
+                                       useMtab, fakeIt, mtab_opts);
                        if (status == TRUE)
                                break;
                }
-               free( fslist);
-               close(fd);
-       } else
-#endif
-       {
+       } else {
                status = do_mount(blockDevice, directory, filesystemType,
-                                                 flags | MS_MGC_VAL, string_flags, useMtab,
-                                                 fakeIt, mtab_opts);
+                               flags | MS_MGC_VAL, string_flags, useMtab,
+                               fakeIt, mtab_opts);
        }
 
        if (status == FALSE) {

diff --git a/util-linux/mount.c b/util-linux/mount.c
index 76cab7d..2353a8a 100644 (file)
--- a/util-linux/mount.c
+++ b/util-linux/mount.c
@@ -83,6 +83,7 @@ extern int mount (__const char *__special_file, __const char *__dir,
                        __const void *__data);
 extern int umount (__const char *__special_file);
 extern int umount2 (__const char *__special_file, int __flags);
+static _syscall3(int, sysfs, int, option, unsigned int, fs_index, char *, buf);
 
 
 extern const char mtab_file[]; /* Defined in utility.c */
@@ -233,72 +234,24 @@ mount_one(char *blockDevice, char *directory, char *filesystemType,
 {
        int status = 0;
 
-       char buf[255];
        if (strcmp(filesystemType, "auto") == 0) {
-               FILE *f = xfopen("/proc/filesystems", "r");
-
-               while (fgets(buf, sizeof(buf), f) != NULL) {
-                       filesystemType = buf;
-                       if (*filesystemType == '\t') {  // Not a nodev filesystem
-
-                               // Add NULL termination to each line
-                               while (*filesystemType && *filesystemType != '\n')
-                                       filesystemType++;
-                               *filesystemType = '\0';
-
-                               filesystemType = buf;
-                               filesystemType++;       // hop past tab
-
-                               status = do_mount(blockDevice, directory, filesystemType,
-                                                                 flags | MS_MGC_VAL, string_flags,
-                                                                 useMtab, fakeIt, mtab_opts);
-                               if (status == TRUE)
-                                       break;
-                       }
-               }
-               fclose(f);
-       } else
-#if defined BB_FEATURE_USE_DEVPS_PATCH
-       if (strcmp(filesystemType, "auto") == 0) {
-               int fd, i, numfilesystems;
-               char device[] = "/dev/mtab";
-               struct k_fstype *fslist;
-
-               /* open device */ 
-               fd = open(device, O_RDONLY);
-               if (fd < 0)
-                       perror_msg_and_die("open failed for `%s'", device);
-
-               /* How many filesystems?  We need to know to allocate enough space */
-               numfilesystems = ioctl (fd, DEVMTAB_COUNT_FILESYSTEMS);
-               if (numfilesystems<0)
-                       perror_msg_and_die("\nDEVMTAB_COUNT_FILESYSTEMS");
-               fslist = (struct k_fstype *) xcalloc ( numfilesystems, sizeof(struct k_fstype));
-
-               /* Grab the list of available filesystems */
-               status = ioctl (fd, DEVMTAB_GET_FILESYSTEMS, fslist);
-               if (status<0)
-                       perror_msg_and_die("\nDEVMTAB_GET_FILESYSTEMS");
-
-               /* Walk the list trying to mount filesystems 
-                * that do not claim to be nodev filesystems */
-               for( i = 0 ; i < numfilesystems ; i++) {
-                       if (fslist[i].mnt_nodev)
-                               continue;
-                       status = do_mount(blockDevice, directory, fslist[i].mnt_type,
-                                                         flags | MS_MGC_VAL, string_flags,
-                                                         useMtab, fakeIt, mtab_opts);
+               int i=0;
+               const int num_of_filesystems = sysfs(3, 0, 0);
+               char buf[255];
+               filesystemType=buf;
+
+               while(i < num_of_filesystems) {
+                       sysfs(2, i++, filesystemType);
+                       status = do_mount(blockDevice, directory, filesystemType,
+                                       flags | MS_MGC_VAL, string_flags,
+                                       useMtab, fakeIt, mtab_opts);
                        if (status == TRUE)
                                break;
                }
-               free( fslist);
-               close(fd);
-       } else
-#endif
-       {
+       } else {
                status = do_mount(blockDevice, directory, filesystemType,
-                                                 flags | MS_MGC_VAL, string_flags, useMtab,
-                                                 fakeIt, mtab_opts);
+                               flags | MS_MGC_VAL, string_flags, useMtab,
+                               fakeIt, mtab_opts);
        }
 
        if (status == FALSE) {

diff --git a/utility.c b/utility.c
index df4573c..76299be 100644 (file)
--- a/utility.c
+++ b/utility.c
@@ -63,8 +63,8 @@
 #include <sys/syscall.h>
 #include <linux/unistd.h>
 
-/* Busybox mount uses either /proc/filesystems or /dev/mtab to get the 
- * list of available filesystems used for the -t auto option */ 
+/* Busybox mount uses either /proc/mounts or /dev/mtab to 
+ * get the list of currently mounted filesystems */ 
 #if defined BB_MOUNT || defined BB_UMOUNT || defined BB_DF
 #  if defined BB_MTAB
 const char mtab_file[] = "/etc/mtab";