Add ucspiserver.h, support posix_spawn() in s6-ipcserverd

Signed-off-by: Laurent Bercot <ska@appnovation.com>

2 files changed, 117 insertions, 0 deletions

diff --git a/src/libs6/deps-lib/s6 b/src/libs6/deps-lib/s6
index 9924d83..13b9a83 100644
--- a/src/libs6/deps-lib/s6
+++ b/src/libs6/deps-lib/s6
@@ -70,4 +70,5 @@ s6_supervise_link.o
 s6_supervise_link_names.o
 s6_supervise_unlink.o
 s6_supervise_unlink_names.o
+s6_ucspiserver_spawn.o
 -lskarnet
diff --git a/src/libs6/s6_ucspiserver_spawn.c b/src/libs6/s6_ucspiserver_spawn.c
new file mode 100644
index 0000000..982d754
--- /dev/null
+++ b/src/libs6/s6_ucspiserver_spawn.c
@@ -0,0 +1,116 @@
+/* ISC license. */
+
+#include <skalibs/sysdeps.h>
+
+#include <stdint.h>
+#include <string.h>
+#include <unistd.h>
+
+#include <skalibs/uint16.h>
+#include <skalibs/fmtscan.h>
+#include <skalibs/djbunix.h>
+
+#include <s6/ucspiserver.h>
+
+#ifdef SKALIBS_HASPOSIXSPAWN
+
+#include <errno.h>
+#include <signal.h>
+#include <stdlib.h>
+#include <spawn.h>
+
+#include <skalibs/config.h>
+#include <skalibs/env.h>
+
+#ifdef SKALIBS_HASPOSIXSPAWNEARLYRETURN
+extern pid_t child_spawn_workaround (pid_t, int const *) ;  /* XXX: non-public skalibs function */
+#endif
+
+pid_t s6_ucspiserver_spawn (int fd, char const *const *argv, char const *const *envp, size_t envlen, char const *modifs, size_t modiflen, size_t modifn)
+{
+  pid_t pid ;
+  posix_spawn_file_actions_t actions ;
+  posix_spawnattr_t attr ;
+  sigset_t set ;
+  int e ;
+  int nopath = !getenv("PATH") ;
+#ifdef SKALIBS_HASPOSIXSPAWNEARLYRETURN
+  int p[2] ;
+#endif
+  char const *newenvp[envlen + modifn + 1] ;
+
+#ifdef SKALIBS_HASPOSIXSPAWNEARLYRETURN
+  if (pipecoe(p) == -1) return 0 ;
+#endif
+  e = posix_spawnattr_init(&attr) ;
+  if (e) goto err ;
+  sigemptyset(&set) ;
+  e = posix_spawnattr_setsigmask(&attr, &set) ;
+  if (e) goto errattr ;
+  e = posix_spawnattr_setflags(&attr, POSIX_SPAWN_SETSIGMASK) ;
+  if (e) goto errattr ;
+  e = posix_spawn_file_actions_init(&actions) ;
+  if (e) goto errattr ;
+  e = posix_spawn_file_actions_adddup2(&actions, fd, 0) ;
+  if (e) goto erractions ;
+  e = posix_spawn_file_actions_adddup2(&actions, fd, 1) ;
+  if (e) goto erractions ;
+  if (fd > 1)
+  {
+    e = posix_spawn_file_actions_addclose(&actions, fd) ;
+    if (e) goto erractions ;
+  }
+
+  env_mergen(newenvp, envlen + modifn + 1, envp, envlen, modifs, modiflen, modifn) ;
+  if (nopath && (setenv("PATH", SKALIBS_DEFAULTPATH, 0) < 0)) { e = errno ; goto erractions ; }
+  e = posix_spawnp(&pid, argv[0], &actions, &attr, (char *const *)argv, (char *const *)newenvp) ;
+  if (nopath) unsetenv("PATH") ;
+  if (e) goto erractions ;
+
+  posix_spawn_file_actions_destroy(&actions) ;
+  posix_spawnattr_destroy(&attr) ;
+#ifdef SKALIBS_HASPOSIXSPAWNEARLYRETURN
+  return child_spawn_workaround(pid, p) ;
+#else
+  return pid ;
+#endif
+
+ erractions:
+  posix_spawn_file_actions_destroy(&actions) ;
+ errattr:
+  posix_spawnattr_destroy(&attr) ;
+ err:
+#ifdef SKALIBS_HASPOSIXSPAWNEARLYRETURN
+  fd_close(p[1]) ;
+  fd_close(p[0]) ;
+#endif
+  errno = e ;
+  return 0 ;
+}
+
+#else
+
+#include <skalibs/strerr.h>
+#include <skalibs/selfpipe.h>
+#include <skalibs/exec.h>
+
+pid_t s6_ucspiserver_spawn (int fd, char const *const *argv, char const *const *envp, size_t envlen, char const *modifs, size_t modiflen, size_t modifn)
+{
+  pid_t pid = fork() ;
+  if (pid == -1) return 0 ;
+  if (!pid)
+  {
+    size_t proglen = strlen(PROG) ;
+    char newprog[proglen + 9] ;
+    memcpy(newprog, PROG, proglen) ;
+    memcpy(newprog, " (child)", 9) ;
+    PROG = newprog ;
+    if ((fd_move(1, fd) == -1) || (fd_copy(0, 1) == -1))
+      strerr_diefu1sys(111, "move fds") ;
+    selfpipe_finish() ;
+    xmexec_fn(argv, envp, envlen, modifs, modiflen, modifn) ;
+  }
+  return pid ;
+}
+
+#endif