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| author | Adhemerval Zanella <adhemerval.zanella@linaro.org> | 2021-03-10 12:26:33 -0300 |
|---|---|---|
| committer | Adhemerval Zanella <adhemerval.zanella@linaro.org> | 2021-07-08 14:08:15 -0300 |
| commit | 882d6e17bc44db687c8de9b357e5ce6c6d501f28 (patch) | |
| tree | 950be2a02a8fed36f09491c1ad9dbb64497a781b /posix/Makefile | |
| parent | 607449506f197cc9514408908f41f22537a47a8c (diff) | |
| download | glibc-882d6e17bc44db687c8de9b357e5ce6c6d501f28.tar.gz | |
posix: Add posix_spawn_file_actions_addclosefrom_np
This patch adds a way to close a range of file descriptors on
posix_spawn as a new file action. The API is similar to the one
provided by Solaris 11 [1], where the file action causes the all open
file descriptors greater than or equal to input on to be closed when
the new process is spawned.
The function posix_spawn_file_actions_addclosefrom_np is safe to be
implemented by iterating over /proc/self/fd, since the Linux spawni.c
helper process does not use CLONE_FILES, so its has own file descriptor
table and any failure (in /proc operation) aborts the process creation
and returns an error to the caller.
I am aware that this file action might be redundant to the current
approach of POSIX in promoting O_CLOEXEC in more interfaces. However
O_CLOEXEC is still not the default and for some specific usages, the
caller needs to close all possible file descriptors to avoid them
leaking. Some examples are CPython (discussed in BZ#10353) and OpenJDK
jspawnhelper [2] (where OpenJDK spawns a helper process to exactly
closes all file descriptors). Most likely any environment which calls
functions that might open file descriptor under the hood and aim to use
posix_spawn might face the same requirement.
Checked on x86_64-linux-gnu and i686-linux-gnu on kernel 5.11 and 4.15.
[1] https://docs.oracle.com/cd/E36784_01/html/E36874/posix-spawn-file-actions-addclosefrom-np-3c.html
[2] https://github.com/openjdk/jdk/blob/master/src/java.base/unix/native/libjava/childproc.c#L82
Diffstat (limited to 'posix/Makefile')
| -rw-r--r-- | posix/Makefile | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/posix/Makefile b/posix/Makefile index e91ea25ba1..d82e43eaad 100644 --- a/posix/Makefile +++ b/posix/Makefile @@ -57,6 +57,7 @@ routines := \ spawn_faction_init spawn_faction_destroy spawn_faction_addclose \ spawn_faction_addopen spawn_faction_adddup2 spawn_valid_fd \ spawn_faction_addchdir spawn_faction_addfchdir \ + spawn_faction_addclosefrom \ spawnattr_init spawnattr_destroy \ spawnattr_getdefault spawnattr_setdefault \ spawnattr_getflags spawnattr_setflags \ @@ -106,7 +107,7 @@ tests := test-errno tstgetopt testfnm runtests runptests \ tst-sysconf-empty-chroot tst-glob_symlinks tst-fexecve \ tst-glob-tilde test-ssize-max tst-spawn4 bug-regex37 \ bug-regex38 tst-regcomp-truncated tst-spawn-chdir \ - tst-wordexp-nocmd tst-execveat + tst-wordexp-nocmd tst-execveat tst-spawn5 # Test for the glob symbol version that was replaced in glibc 2.27. ifeq ($(have-GLIBC_2.26)$(build-shared),yesyes) @@ -276,6 +277,7 @@ tst-exec-static-ARGS = $(tst-exec-ARGS) tst-execvpe5-ARGS = -- $(host-test-program-cmd) tst-spawn-ARGS = -- $(host-test-program-cmd) tst-spawn-static-ARGS = $(tst-spawn-ARGS) +tst-spawn5-ARGS = -- $(host-test-program-cmd) tst-dir-ARGS = `pwd` `cd $(common-objdir)/$(subdir); pwd` `cd $(common-objdir); pwd` $(objpfx)tst-dir tst-chmod-ARGS = $(objdir) tst-vfork3-ARGS = --test-dir=$(objpfx) |