1 files changed, 55 insertions, 0 deletions
diff --git a/src/libenvexec/child_spawn3.c b/src/libenvexec/child_spawn3.c
new file mode 100644
index 0000000..75551d2
--- /dev/null
+++ b/src/libenvexec/child_spawn3.c
@@ -0,0 +1,55 @@
+/* ISC license. */
+
+#include <unistd.h>
+
+#include <skalibs/types.h>
+#include <skalibs/env.h>
+#include <skalibs/djbunix.h>
+#include <skalibs/cspawn.h>
+
+pid_t child_spawn3 (char const *prog, char const *const *argv, char const *const *envp, int *fds)
+{
+  pid_t pid ;
+  int p[3][2] ;
+
+  if (pipe(p[0]) == -1) return 0 ;
+  if (ndelay_on(p[0][0]) == -1 || coe(p[0][0]) == -1 || pipe(p[1]) == -1) goto errp0 ;
+  if (ndelay_on(p[1][1]) == -1 || coe(p[1][1]) == -1 || pipe(p[2]) == -1) goto errp1 ;
+  if (ndelay_on(p[2][0]) == -1 || coe(p[2][0]) == -1) goto err ;
+
+  {
+    cspawn_fileaction fa[2] =
+    {
+      [0] = { .type = CSPAWN_FA_MOVE, .x = { .fd2 = { [0] = fds[0], [1] = p[1][0] } } },
+      [1] = { .type = CSPAWN_FA_MOVE, .x = { .fd2 = { [0] = fds[1], [1] = p[0][1] } } }
+    } ;
+    size_t envlen = env_len(envp) ;
+    size_t m = sizeof(SKALIBS_CHILD_SPAWN_FDS_ENVVAR) ;
+    char modifs[sizeof(SKALIBS_CHILD_SPAWN_FDS_ENVVAR) + UINT_FMT] = SKALIBS_CHILD_SPAWN_FDS_ENVVAR "=" ;
+    char const *newenv[envlen + 2] ;
+    m += uint_fmt(modifs + sizeof(SKALIBS_CHILD_SPAWN_FDS_ENVVAR), p[2][1]) ;
+    modifs[m++] = 0 ;
+    env_mergen(newenv, envlen + 2, envp, envlen, modifs, m, 1) ;
+    pid = cspawn(prog, argv, newenv, CSPAWN_FLAGS_SIGBLOCKNONE, fa, 2) ;
+    if (!pid) goto err ;
+  }
+
+  fd_close(p[2][1]) ;
+  fd_close(p[1][0]) ;
+  fd_close(p[0][1]) ;
+  fds[0] = p[0][0] ;
+  fds[1] = p[1][1] ;
+  fds[2] = p[2][0] ;
+  return pid ;
+
+ err:
+  fd_close(p[2][1]) ;
+  fd_close(p[2][0]) ;
+ errp1:
+  fd_close(p[1][1]) ;
+  fd_close(p[1][0]) ;
+ errp0:
+  fd_close(p[0][1]) ;
+  fd_close(p[0][0]) ;
+  return 0 ;
+}