Hi,
When I use the fchdir emulation on a Linux 2.4.x system (that doesn't have
openat() and similar), the coreutils-6.7 tests install/basic-1 and mkdir/p-3
fail. The reason is this part:
$ mkdir -p sub1/d
$ cd sub1/d
$ chmod a-rx ..
$ chmod a-r .
$ ginstall -d rel/a rel/b
ginstall: cannot create directory `rel': Permission denied
This error message appears once, for rel/a. For the second argument, rel/b,
the directory already exists and no error message is shown.
The system call log (from "strace -f") is attached. Can someone decipher it?
1) Why is the subprocess 2229 showing an error message as a result of
open(".", O_RDONLY|O_LARGEFILE) = -1 / EACCES ? Isn't the point of forking
precisely to be able to "restore" the working directory in situations like
this?
2) Why is the subdirectory rel/a not created, whereas rel/b is? The parent
process only propagates error codes, until a savewd_restore call; whereas the
child process does not even attempt to create the rel/a directory.
Bruno
============== strace -f /build/coreutils-6.7-fchdir/src/ginstall -d rel/a
rel/b =============
2228 brk(0) = 0x80584b0
2228 brk(0x80794b0) = 0x80794b0
2228 brk(0x807a000) = 0x807a000
2228 geteuid32() = 101
2228 umask(0) = 022
2228 mkdir("rel", 0755) = 0
2228 open("rel",
O_RDONLY|O_NONBLOCK|O_NOCTTY|O_LARGEFILE|O_DIRECTORY|O_NOFOLLOW) = 5
2228 fstat64(5, {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
2228 getcwd("/build/coreutils-6.7-fchdir/tests/install/sub1/d", 4096) = 49
2228 lstat64("/build/coreutils-6.7-fchdir/tests/install/sub1/d/rel",
0xbfffe218) = -1 EACCES (Permission denied)
2228 brk(0x8079000) = 0x8079000
2228 open(".", O_RDONLY|O_LARGEFILE) = -1 EACCES (Permission denied)
2228 fork() = 2229
2228 close(5) = 0
2228 waitpid(2229, <unfinished ...>
2229 --- SIGSTOP (Stopped (signal)) @ 0 (0) ---
2229 close(5) = 0
2229 write(2, "/build/coreutils-6.7-fchdir/src/"..., 42) = 42
2229 write(2, "cannot create directory `rel\'", 29) = 29
2229 write(2, ": Permission denied", 19) = 19
2229 write(2, "\n", 1) = 1
2229 exit_group(1) = ?
2228 <... waitpid resumed> [WIFEXITED(s) && WEXITSTATUS(s) == 1], 0) = 2229
2228 --- SIGCHLD (Child exited) @ 0 (0) ---
2228 mkdir("rel", 0755) = -1 EEXIST (File exists)
2228 chdir("rel") = 0
2228 mkdir("b", 0755) = 0
2228 open("b",
O_RDONLY|O_NONBLOCK|O_NOCTTY|O_LARGEFILE|O_DIRECTORY|O_NOFOLLOW) = 5
2228 fstat64(5, {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
2228 getcwd("/build/coreutils-6.7-fchdir/tests/install/sub1/d/rel", 4096) = 53
2228 lstat64("/build/coreutils-6.7-fchdir/tests/install/sub1/d/rel/b",
0xbfffe258) = -1 EACCES (Permission denied)
2228 fstat64(5, {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
2228 close(5) = 0
2228 close(1) = 0
2228 close(2) = 0
2228 exit_group(1) = ?
Similarly with mkdir:
============= strace -f /build/coreutils-6.7-fchdir/src/mkdir -p rel/a rel/b
================
2428 brk(0) = 0x804e784
2428 brk(0x806f784) = 0x806f784
2428 brk(0x8070000) = 0x8070000
2428 umask(0) = 022
2428 mkdir("rel", 0755) = 0
2428 open("rel",
O_RDONLY|O_NONBLOCK|O_NOCTTY|O_LARGEFILE|O_DIRECTORY|O_NOFOLLOW) = 5
2428 fstat64(5, {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
2428 getcwd("/build/coreutils-6.7-fchdir/tests/mkdir/sub1/d", 4096) = 47
2428 lstat64("/build/coreutils-6.7-fchdir/tests/mkdir/sub1/d/rel", 0xbfffe2a8)
= -1 EACCES (Permission denied)
2428 brk(0x806f000) = 0x806f000
2428 open(".", O_RDONLY|O_LARGEFILE) = -1 EACCES (Permission denied)
2428 fork() = 2429
2428 close(5) = 0
2428 waitpid(2429, <unfinished ...>
2429 --- SIGSTOP (Stopped (signal)) @ 0 (0) ---
2429 close(5) = 0
2429 write(2, "/build/coreutils-6.7-fchdir/src/"..., 39) = 39
2429 write(2, "cannot create directory `rel\'", 29) = 29
2429 write(2, ": Permission denied", 19) = 19
2429 write(2, "\n", 1) = 1
2429 exit_group(1) = ?
2428 <... waitpid resumed> [WIFEXITED(s) && WEXITSTATUS(s) == 1], 0) = 2429
2428 --- SIGCHLD (Child exited) @ 0 (0) ---
2428 mkdir("rel", 0755) = -1 EEXIST (File exists)
2428 chdir("rel") = 0
2428 mkdir("b", 0755) = 0
2428 close(1) = 0
2428 close(2) = 0
2428 exit_group(1) = ?
