Fix case where s6-tls[cd] would sometimes not detect an application and remain there forever with its zombie, both condemned to err in limbo for all eternity, the living and the dead, hand in hand

7 files changed, 97 insertions, 65 deletions

diff --git a/src/stls/deps-lib/stls b/src/stls/deps-lib/stls
index 03cebfa..7ecfa0b 100644
--- a/src/stls/deps-lib/stls
+++ b/src/stls/deps-lib/stls
@@ -1,4 +1,4 @@
-stls_clean_tls_and_spawn.o
+stls_prep_spawn_drop.o
 stls_run.o
 stls_s6tlsc.o
 stls_s6tlsd.o
diff --git a/src/stls/stls-internal.h b/src/stls/stls-internal.h
index 48a119e..d5c59e7 100644
--- a/src/stls/stls-internal.h
+++ b/src/stls/stls-internal.h
@@ -6,6 +6,6 @@
 #include <sys/types.h>
 #include <stdint.h>
 
-extern pid_t stls_clean_tls_and_spawn (char const *const *, char const *const *, int *, uint32_t) ;
+extern pid_t stls_prep_spawn_drop (char const *const *, char const *const *, int *, uid_t, gid_t, uint32_t) ;
 
 #endif
diff --git a/src/stls/stls_clean_tls_and_spawn.c b/src/stls/stls_clean_tls_and_spawn.c
deleted file mode 100644
index 37ea619..0000000
--- a/src/stls/stls_clean_tls_and_spawn.c
+++ /dev/null
@@ -1,21 +0,0 @@
-/* ISC license. */
-
-#include <sys/types.h>
-#include <skalibs/env.h>
-#include <skalibs/djbunix.h>
-#include "stls-internal.h"
-
-pid_t stls_clean_tls_and_spawn (char const *const *argv, char const *const *envp, int *fds, uint32_t options)
-{
-  if (!(options & 1)) return child_spawn2(argv[0], argv, envp, fds) ;
-  else
-  {
-    char const modifs[] = "CADIR\0CAFILE\0KEYFILE\0CERTFILE\0TLS_UID\0TLS_GID" ;
-    size_t modiflen = sizeof(modifs) ;
-    size_t n = env_len(envp) ;
-    char const *newenv[n + 7] ;
-    size_t newenvlen = env_merge(newenv, n+7, envp, n, modifs, modiflen) ;
-    if (!newenvlen) return 0 ;
-    return child_spawn2(argv[0], argv, newenv, fds) ;
-  }
-}
diff --git a/src/stls/stls_prep_spawn_drop.c b/src/stls/stls_prep_spawn_drop.c
new file mode 100644
index 0000000..c6f4e13
--- /dev/null
+++ b/src/stls/stls_prep_spawn_drop.c
@@ -0,0 +1,35 @@
+/* ISC license. */
+
+#include <unistd.h>
+#include <signal.h>
+#include <skalibs/env.h>
+#include <skalibs/strerr2.h>
+#include <skalibs/djbunix.h>
+#include <skalibs/selfpipe.h>
+#include "stls-internal.h"
+
+pid_t stls_prep_spawn_drop (char const *const *argv, char const *const *envp, int *fds, uid_t uid, gid_t gid, uint32_t options)
+{
+  pid_t pid ;
+
+  fds[4] = selfpipe_init() ;
+  if (fds[4] < 0) strerr_diefu1sys(111, "init selfpipe") ;
+  if (selfpipe_trap(SIGCHLD) < 0) strerr_diefu1sys(111, "trap SIGCHLD") ;
+
+  if (!(options & 1)) pid = child_spawn2(argv[0], argv, envp, fds) ;
+  else
+  {
+    char const modifs[] = "CADIR\0CAFILE\0KEYFILE\0CERTFILE\0TLS_UID\0TLS_GID" ;
+    size_t modiflen = sizeof(modifs) ;
+    size_t n = env_len(envp) ;
+    char const *newenv[n + 7] ;
+    size_t newenvlen = env_merge(newenv, n+7, envp, n, modifs, modiflen) ;
+    if (!newenvlen) return 0 ;
+    pid = child_spawn2(argv[0], argv, newenv, fds) ;
+  }
+
+  if (!pid) strerr_diefu2sys(111, "spawn ", argv[0]) ;
+  if (gid && setgid(gid) < 0) strerr_diefu1sys(111, "setgid") ;
+  if (uid && setuid(uid) < 0) strerr_diefu1sys(111, "setuid") ;
+  return pid ;
+}
diff --git a/src/stls/stls_run.c b/src/stls/stls_run.c
index 1a035e2..3f2742d 100644
--- a/src/stls/stls_run.c
+++ b/src/stls/stls_run.c
@@ -114,12 +114,31 @@ static void closeit (struct tls *ctx, int *fds, int brutal)
   fd_close(fds[3]) ; fds[3] = -1 ;
 }
 
-int stls_run (struct tls *ctx, int *fds, unsigned int verbosity, uint32_t options, tain_t const *tto)
+static void handle_signals (pid_t pid, int *e)
+{
+  for (;;) switch (selfpipe_read())
+  {
+    case -1 : strerr_diefu1sys(111, "read selfpipe") ;
+    case 0 : return ;
+    case SIGCHLD :
+    {
+      int wstat ;
+      if (wait_pid_nohang(pid, &wstat) == pid)
+      {
+        *e = wstat ;
+        return ;
+      }
+    }
+  }
+}
+
+int stls_run (struct tls *ctx, int *fds, pid_t pid, unsigned int verbosity, uint32_t options, tain_t const *tto)
 {
   tlsbuf_t b[2] = { { .blockedonother = 0 }, { .blockedonother = 0 } } ;
-  iopause_fd x[4] ;
+  iopause_fd x[5] = { { .fd = fds[4], .events = IOPAUSE_READ } } ;
   unsigned int xindex[4] ;
   unsigned int i = 0 ;
+  int e = -1 ;
 
   for (; i < 2 ; i++)
   {
@@ -133,7 +152,7 @@ int stls_run (struct tls *ctx, int *fds, unsigned int verbosity, uint32_t option
   for (;;)
   {
     tain_t deadline ;
-    unsigned int xlen = 0 ;
+    unsigned int xlen = 1 ;
     int r ;
 
     tain_add_g(&deadline, fds[0] >= 0 && fds[2] >= 0 && buffer_isempty(&b[0].b) && buffer_isempty(&b[1].b) ? tto : &tain_infinite_relative) ;
@@ -147,7 +166,7 @@ int stls_run (struct tls *ctx, int *fds, unsigned int verbosity, uint32_t option
       x[xlen].events = IOPAUSE_READ ;
       xindex[0] = xlen++ ;
     }
-    else xindex[0] = 4 ;
+    else xindex[0] = 5 ;
 
     if (fds[1] >= 0 && buffer_iswritable(&b[1].b))
     {
@@ -155,7 +174,7 @@ int stls_run (struct tls *ctx, int *fds, unsigned int verbosity, uint32_t option
       x[xlen].events = IOPAUSE_WRITE ;
       xindex[1] = xlen++ ;
     }
-    else xindex[1] = 4 ;
+    else xindex[1] = 5 ;
 
     if (fds[2] >= 0 && !b[1].blockedonother && buffer_isreadable(&b[1].b))
     {
@@ -163,7 +182,7 @@ int stls_run (struct tls *ctx, int *fds, unsigned int verbosity, uint32_t option
       x[xlen].events = IOPAUSE_READ ;
       xindex[2] = xlen++ ;
     }
-    else xindex[2] = 4 ;
+    else xindex[2] = 5 ;
 
     if (fds[3] >= 0 && !b[0].blockedonother && buffer_iswritable(&b[0].b))
     {
@@ -171,9 +190,9 @@ int stls_run (struct tls *ctx, int *fds, unsigned int verbosity, uint32_t option
       x[xlen].events = IOPAUSE_WRITE ;
       xindex[3] = xlen++ ;
     }
-    else xindex[3] = 4 ;
+    else xindex[3] = 5 ;
 
-    if (!xlen) break ;
+    if (xlen == 1) break ;
 
 
    /* poll() */
@@ -184,6 +203,7 @@ int stls_run (struct tls *ctx, int *fds, unsigned int verbosity, uint32_t option
     {
       fd_close(fds[0]) ; fds[0] = -1 ;
       closeit(ctx, fds, options & 1) ;
+      if (e >= 0) break ;
       continue ;
     }
 
@@ -192,9 +212,14 @@ int stls_run (struct tls *ctx, int *fds, unsigned int verbosity, uint32_t option
         x[xlen].revents |= IOPAUSE_READ | IOPAUSE_WRITE ;
 
 
+   /* Signal */
+
+    if (x[0].revents & IOPAUSE_READ) handle_signals(pid, &e) ;
+
+
    /* Flush to local */
 
-    if (xindex[1] < 4 && x[xindex[1]].revents & IOPAUSE_WRITE)
+    if (xindex[1] < 5 && x[xindex[1]].revents & IOPAUSE_WRITE)
     {
       r = buffer_flush(&b[1].b) ;
       if (!r && !error_isagain(errno))
@@ -217,7 +242,7 @@ int stls_run (struct tls *ctx, int *fds, unsigned int verbosity, uint32_t option
 
    /* Flush to remote */
 
-    if (xindex[3] < 4 && x[xindex[3]].revents & IOPAUSE_WRITE)
+    if (xindex[3] < 5 && x[xindex[3]].revents & IOPAUSE_WRITE)
     {
       r = buffer_tls_flush(ctx, b) ;
       if (r < 0)
@@ -225,27 +250,35 @@ int stls_run (struct tls *ctx, int *fds, unsigned int verbosity, uint32_t option
         strerr_warnwu2x("write to peer: ", tls_error(ctx)) ;
         fd_close(fds[0]) ; fds[0] = -1 ;
       }
-      if (r && fds[0] < 0) closeit(ctx, fds, options & 1) ;
+      if (r && fds[0] < 0)
+      {
+        closeit(ctx, fds, options & 1) ;
+        if (e >= 0) break ;
+      }
     }
 
 
    /* Fill from local */
 
-    if (xindex[0] < 4 && x[xindex[0]].revents & IOPAUSE_READ)
+    if (xindex[0] < 5 && x[xindex[0]].revents & IOPAUSE_READ)
     {
       r = sanitize_read(buffer_fill(&b[0].b)) ;
       if (r < 0)
       {
         if (errno != EPIPE) strerr_warnwu1sys("read from application") ;
         fd_close(fds[0]) ; fds[0] = -1 ;
-        if (buffer_isempty(&b[0].b)) closeit(ctx, fds, options & 1) ;
+        if (buffer_isempty(&b[0].b))
+        {
+          closeit(ctx, fds, options & 1) ;
+          if (e >= 0) break ;
+        }
       }
     }
 
 
    /* Fill from remote */
 
-    if (xindex[2] < 4 && x[xindex[2]].revents & IOPAUSE_READ)
+    if (xindex[2] < 5 && x[xindex[2]].revents & IOPAUSE_READ)
     {
       r = buffer_tls_fill(ctx, b) ;
       if (r < 0)
@@ -273,5 +306,5 @@ int stls_run (struct tls *ctx, int *fds, unsigned int verbosity, uint32_t option
   if (fds[0] >= 0) fd_close(fds[0]) ;
   if (fds[3] >= 0) fd_close(fds[3]) ;
   if (fds[2] >= 0) fd_close(fds[2]) ;
-  return 0 ;
+  return e ;
 }
diff --git a/src/stls/stls_s6tlsc.c b/src/stls/stls_s6tlsc.c
index a9a2c98..87a45ac 100644
--- a/src/stls/stls_s6tlsc.c
+++ b/src/stls/stls_s6tlsc.c
@@ -14,11 +14,12 @@
 
 int stls_s6tlsc (char const *const *argv, char const *const *envp, tain_t const *tto, uint32_t preoptions, uint32_t options, uid_t uid, gid_t gid, unsigned int verbosity, char const *servername, int *sfd)
 {
-  int fds[4] = { sfd[0], sfd[1], sfd[0], sfd[1] } ;
+  int fds[5] = { sfd[0], sfd[1], sfd[0], sfd[1] } ;
   struct tls *ctx ;
   struct tls_config *cfg ;
   pid_t pid ;
   char const *x ;
+  int wstat ;
 
   if (tls_init() < 0) strerr_diefu1sys(111, "tls_init") ;
   cfg = tls_config_new() ;
@@ -72,23 +73,14 @@ int stls_s6tlsc (char const *const *argv, char const *const *envp, tain_t const
   if (!ctx) strerr_diefu1sys(111, "tls_client") ;
   if (tls_configure(ctx, cfg) < 0) diectx(97, ctx, "tls_configure") ;
 
-  pid = stls_clean_tls_and_spawn(argv, envp, fds, !!(preoptions & 2)) ;
-  if (!pid) strerr_diefu2sys(111, "spawn ", argv[0]) ;
-  if (gid && setgid(gid) < 0) strerr_diefu1sys(111, "setgid") ;
-  if (uid && setuid(uid) < 0) strerr_diefu1sys(111, "setuid") ;
+  pid = stls_prep_spawn_drop(argv, envp, fds, uid, gid, !!(preoptions & 2)) ;
 
   if (tls_connect_fds(ctx, fds[2], fds[3], servername) < 0)
     diectx(97, ctx, "tls_connect_fds") ;
   tls_config_free(cfg) ;
   if (tls_handshake(ctx) < 0) diectx(97, ctx, "perform SSL handshake") ;
 
-  {
-    int wstat ;
-    int r = stls_run(ctx, fds, verbosity, options, tto) ;
-    if (r < 0) strerr_diefu1sys(111, "run SSL engine") ;
-    else if (r) diectx(98, ctx, "maintain SSL connection to peer") ;
-    tls_free(ctx) ;
-    if (wait_pid(pid, &wstat) < 0) strerr_diefu1sys(111, "wait_pid") ;
-    return wait_estatus(wstat) ;
-  }
+  wstat = stls_run(ctx, fds, pid, verbosity, options, tto) ;
+  if (wstat < 0 && wait_pid(pid, &wstat) < 0) strerr_diefu1sys(111, "wait_pid") ;
+  return wait_estatus(wstat) ;
 }
diff --git a/src/stls/stls_s6tlsd.c b/src/stls/stls_s6tlsd.c
index fd59d48..07446e7 100644
--- a/src/stls/stls_s6tlsd.c
+++ b/src/stls/stls_s6tlsd.c
@@ -15,12 +15,13 @@
 
 int stls_s6tlsd (char const *const *argv, char const *const *envp, tain_t const *tto, uint32_t preoptions, uint32_t options, uid_t uid, gid_t gid, unsigned int verbosity)
 {
-  int fds[4] = { 0, 1, 0, 1 } ;
+  int fds[5] = { 0, 1, 0, 1 } ;
   struct tls *cctx ;
   struct tls *ctx ;
   struct tls_config *cfg ;
   pid_t pid ;
   char const *x ;
+  int wstat ;
 
   if (tls_init() < 0) strerr_diefu1sys(111, "tls_init") ;
   cfg = tls_config_new() ;
@@ -76,22 +77,14 @@ int stls_s6tlsd (char const *const *argv, char const *const *envp, tain_t const
   if (tls_configure(ctx, cfg) < 0) diectx(97, ctx, "tls_configure") ;
   tls_config_free(cfg) ;
 
-  pid = stls_clean_tls_and_spawn(argv, envp, fds, !!(preoptions & 2)) ;
-  if (!pid) strerr_diefu2sys(111, "spawn ", argv[0]) ;
-  if (gid && setgid(gid) < 0) strerr_diefu1sys(111, "setgid") ;
-  if (uid && setuid(uid) < 0) strerr_diefu1sys(111, "setuid") ;
+  pid = stls_prep_spawn_drop(argv, envp, fds, uid, gid, !!(preoptions & 2)) ;
 
   if (tls_accept_fds(ctx, &cctx, fds[2], fds[3]) < 0)
     diectx(97, ctx, "tls_accept_fds") ;
   tls_free(ctx) ;
   if (tls_handshake(cctx) < 0) diectx(97, cctx, "perform SSL handshake") ;
 
-  {
-    int wstat ;
-    int r = stls_run(cctx, fds, verbosity, options, tto) ;
-    if (r < 0) strerr_diefu1sys(111, "run SSL engine") ;
-    else if (r) diectx(98, cctx, "maintain SSL connection to peer") ;
-    if (wait_pid(pid, &wstat) < 0) strerr_diefu1sys(111, "wait_pid") ;
-    return wait_estatus(wstat) ;
-  }
+  wstat = stls_run(cctx, fds, pid, verbosity, options, tto) ;
+  if (wstat < 0 && wait_pid(pid, &wstat) < 0) strerr_diefu1sys(111, "wait_pid") ;
+  return wait_estatus(wstat) ;
 }