adb shell下提示read-only file system

当使用adb shell时，向/system目录及其子目录写文件时经常提示“read-only file system”。其实产生该提示的原因很简单：/system是以ro模式挂载的，因此我们所要做的就是以读写模式(rw)重新挂载需要修改的目录（本例中为/system），具体流程如下：
1. 进入adb shell并查看当前挂在情况

命令号下输入：adb shell
#mount

这时候看到当前挂载情况

rootfs on / type rootfs (rw,relatime)
tmpfs on /dev type tmpfs (rw,relatime,mode=755)
devpts on /dev/pts type devpts (rw,relatime,mode=600)
proc on /proc type proc (rw,relatime)
sysfs on /sys type sysfs (rw,relatime)
none on /acct type cgroup (rw,relatime,cpuacct)
tmpfs on /mnt/asec type tmpfs (rw,relatime,mode=755,gid=1000)
tmpfs on /mnt/obb type tmpfs (rw,relatime,mode=755,gid=1000)
none on /dev/cpuctl type cgroup (rw,relatime,cpu)
/dev/block/mmcblk0p25 on /system type ext4 (ro,relatime,barrier=1,data=ordered)
/dev/block/mmcblk0p26 on /data type ext4 (rw,nosuid,nodev,noatime,barrier=1,data=ordered,noauto_da_alloc)
/dev/block/mmcblk0p27 on /cache type ext4 (rw,nosuid,nodev,noatime,barrier=1,data=ordered)
/dev/block/mmcblk0p28 on /devlog type ext4 (rw,nosuid,nodev,noatime,barrier=1,data=ordered)
/data/d on /data/d type debugfs (rw,relatime)
/sys/kernel/debug on /sys/kernel/debug type debugfs (rw,relatime)
/dev/block/vold/179:65 on /mnt/sdcard type vfat (rw,dirsync,nosuid,nodev,noexec,relatime,uid=1000,gid=1015,fmask=0602,dmask=0602,allow_utime=0020,codepage=cp437,iocharset=iso8859-1,shortname=mixed,utf8,errors=remount-ro)
/dev/block/vold/179:65 on /mnt/secure/asec type vfat (rw,dirsync,nosuid,nodev,noexec,relatime,uid=1000,gid=1015,fmask=0602,dmask=0602,allow_utime=0020,codepage=cp437,iocharset=iso8859-1,shortname=mixed,utf8,errors=remount-ro)
tmpfs on /mnt/sdcard/.android_secure type tmpfs (ro,relatime,size=0k,mode=000)

我们感兴趣的是

dev/block/mmcblk0p25 on /system type ext4 (ro,relatime,barrier=1,data=ordered)

可以看到system是以只读权限挂载的

2. 重新挂载需要修改权限的目录

#mount -o remount -o rw /system

具体的可以看下mount的参数。
3. 查看修改后的结果

# mount
rootfs on / type rootfs (rw,relatime)
tmpfs on /dev type tmpfs (rw,relatime,mode=755)
devpts on /dev/pts type devpts (rw,relatime,mode=600)
proc on /proc type proc (rw,relatime)
sysfs on /sys type sysfs (rw,relatime)
none on /acct type cgroup (rw,relatime,cpuacct)
tmpfs on /mnt/asec type tmpfs (rw,relatime,mode=755,gid=1000)
tmpfs on /mnt/obb type tmpfs (rw,relatime,mode=755,gid=1000)
none on /dev/cpuctl type cgroup (rw,relatime,cpu)
/dev/block/mmcblk0p25 on /system type ext4 (rw,relatime,barrier=1,data=ordered)
/dev/block/mmcblk0p26 on /data type ext4 (rw,nosuid,nodev,noatime,barrier=1,data=ordered,noauto_da_alloc)
/dev/block/mmcblk0p27 on /cache type ext4 (rw,nosuid,nodev,noatime,barrier=1,data=ordered)
/dev/block/mmcblk0p28 on /devlog type ext4 (rw,nosuid,nodev,noatime,barrier=1,data=ordered)
/data/d on /data/d type debugfs (rw,relatime)
/sys/kernel/debug on /sys/kernel/debug type debugfs (rw,relatime)
/dev/block/vold/179:65 on /mnt/sdcard type vfat (rw,dirsync,nosuid,nodev,noexec,relatime,uid=1000,gid=1015,fmask=0602,dmask=0602,allow_utime=0020,codepage=cp437,iocharset=iso8859-1,shortname=mixed,utf8,errors=remount-ro)
/dev/block/vold/179:65 on /mnt/secure/asec type vfat (rw,dirsync,nosuid,nodev,noexec,relatime,uid=1000,gid=1015,fmask=0602,dmask=0602,allow_utime=0020,codepage=cp437,iocharset=iso8859-1,shortname=mixed,utf8,errors=remount-ro)
tmpfs on /mnt/sdcard/.android_secure type tmpfs (ro,relatime,size=0k,mode=000)
#

大功告成。其他目录同理。尽情adb push/pull 啥的吧