when I looked a little closer at what adb backup was doing, I realized that it was communicating with an adb server running in parallel and, by mimicking the conversation with python, I managed to get what I wanted. *(note that a small error was present in the question : the string to use with printf is "\x1f\x8b\x08\x00\x00\x00\x00\x00").* I still have a slight problem because the tar command ends with an error : *(the same error is also present with adb, printf and tail).* $ adb devices List of devices attached CB5A2B0M9R device $ python3 adbackup.py > /tmp/mybackup.tgz $ tar tvzf /tmp/mybackup.tgz ... all my files are here :-) gzip: stdin: unexpected end of file tar: Child returned status 1 tar: Error is not recoverable: exiting now adbackup.py : #!/usr/bin/python3 # strace adb backup -all -f /tmp/backup.ab # ... # unlink("/tmp/backup.ab") = 0 # creat("/tmp/backup.ab", 0640) = 3 # ... # socket(AF_INET, SOCK_STREAM, IPPROTO_IP) = 4 # bind(4, {sa_family=AF_INET, sin_port=htons(0), sin_addr=inet_addr("127.0.0.1")}, 16) = 0 # connect(4, {sa_family=AF_INET, sin_port=htons(5037), sin_addr=inet_addr("127.0.0.1")}, 16) = 0 # setsockopt(4, SOL_TCP, TCP_NODELAY, [1], 4) = 0 # write(4, "0012host:transport-any", 22) = 22 # read(4, "OKAY", 4) = 4 # write(4, "000ebackup: '-all'", 18) = 18 # read(4, "OKAY", 4) = 4 # fstat(1, {st_mode=S_IFCHR|0620, st_rdev=makedev(0x88, 0x1), ...}) = 0 # write(1, "Now unlock your device and confi"..., 59) = 59 # read(4, "ANDROID BACKUP\n4\n1\nnone\n", 32768) = 24 # write(3, "ANDROID BACKUP\n4\n1\nnone\n", 24) = 24 # read(4, "x\332", 32768) = 2 # write(3, "x\332", 2) = 2 # read(4, "\344VY\256\35E\f}\337o\25\254 \361\\U\253A\256\301(\37$Q\22\366\317\251\233\274(\240"..., 32768) = 967 import socket, sys s = socket.socket(socket.AF_INET, socket.SOCK_STREAM) s.connect(("localhost", 5037)) s.sendall(b"0012host:transport-any") data = s.recv(4) # b"OKAY" s.sendall(b"000ebackup: '-all'") data = s.recv(4) # b"OKAY" data = s.recv(32768) # b"ANDROID BACKUP\n4\n1\nnone\n" sys.stdout.buffer.write(b"\x1f\x8b\x08\x00\x00\x00\x00\x00") data = s.recv(32768) while data: sys.stdout.buffer.write(data) data = s.recv(32768) regards, lacsaP. Le jeu. 16 mai 2019 à 10:57, Pascal <patatetom@gmail.com> a écrit :
hello,
I'm looking for a solution for the problem below : all leads are welcome !
the adb tool is able to make a backup of a smartphone in a file: adb backup -all -f mybackup.ab
however, the file mybackup.ab has a particular format that prevents it from being used "simply". to convert it into a tgz archive, it is possible to do this: ( printf "\x1f\x8b\x08\x08\x00\x00\x00\x00\x00\x00\x00"; tail -c +25 mybackup.ab ) > mybackup.tgz
but in this case, I can easily end up with two files of 16Gb or more... to avoid this volume problem, I tried to do this: mkfifo backup.fifo adb backup -all -f backup.fifo & ( printf "\x1f\x8b\x08\x08\x00\x00\x00\x00\x00\x00" ; tail -c +25 backup.fifo) > mybackup.tgz
but adb systematically breaks my named pipe and my code doesn't work as expected. how to prevent adb from breaking the named pipe ? I'm considering using fuse but there may be a simpler way...
regards, lacsaP.