From ee0b1bc6a1955c02a07cb84e96b8803be8562fc3 Mon Sep 17 00:00:00 2001
From: Ian Jackson <ijackson@chiark.greenend.org.uk>
Date: Tue, 29 Mar 2016 21:20:42 +0100
Subject: [PATCH] cgi-fcgi-interp: Fixes from tests.  Seems to mostly work.

---
 cprogs/cgi-fcgi-interp.c | 100 ++++++++++++++++++++++++---------------
 1 file changed, 63 insertions(+), 37 deletions(-)

diff --git a/cprogs/cgi-fcgi-interp.c b/cprogs/cgi-fcgi-interp.c
index c0152cd..5aeee72 100644
--- a/cprogs/cgi-fcgi-interp.c
+++ b/cprogs/cgi-fcgi-interp.c
@@ -100,14 +100,10 @@
  *  - stat the socket and check its timestamp
  *       if it is too old, unlink it
  *  - dup stderr, mark no cloexec
- *  - run     cgi-fcgi -connect SOCKET       \
- *                cgi-fcgi-interp \
- *                --stage2 <was-stderr> <socket>      \
- -c<check-interval>		\
- *               \
- *                <interp> <script>
+ *  - set CHIARKUTILS_CGIFCGIINTERP_STAGE2=<stderr-copy-fd>
+ *  - run     cgi-fcgi -connect SOCKET <script>
  *
- * --stage2 does this:
+ * When CHIARKUTILS_CGIFCGIINTERP_STAGE2 is set, --stage2 does this:
  *  - dup2 <was-stderr> to fd 2
  *  - open /dev/null and expect fd 1 (and if not, close it)
  *  - become a new process group
@@ -150,11 +146,14 @@
 #define diee common_diee
 
 #define MINHEXHASH 33
+#define STAGE2_VAR "CHIARKUTILS_CGIFCGIINTERP_STAGE2"
 
 static const char *interp, *ident;
-static int numservers=4, debugmode, stage2;
+static int numservers=4, debugmode;
 static int check_interval=300;
 
+const char *stage2;
+
 void diee(const char *m) {
   err(127, "error: %s failed", m);
 }
@@ -188,7 +187,6 @@ static const struct cmdinfo cmdinfos[]= {
   { 0, 'M',   1, .call=of_iassign, .iassignto= &numservers      },
   { 0, 'D',   0, .iassignto= &debugmode, .arg= 1 },
   { 0, 'c',   1, .call=of_iassign, .iassignto= &check_interval  },
-  { "--stage2",0, 0, .iassignto= &stage2, .arg= 1 },
   { 0 }
 };
 
@@ -295,7 +293,7 @@ static void find_socket_path(void) {
       err(127,"mkdir %s",run_base);
   }
 
-  socket_path = m_asprintf("%s/g%s",run_base,ident);
+  socket_path = m_asprintf("%s/s%s",run_base,ident);
 }  
 
 /*
@@ -340,30 +338,62 @@ static void find_socket_path(void) {
 
 
 
-static bool stab_isnewer(const struct stat *a, const struct stat *b) {
 #ifdef st_mtime
+
+static bool stab_isnewer(const struct stat *a, const struct stat *b) {
+  if (debugmode)
+    fprintf(stderr,"stab_isnewer mtim %lu.%06lu %lu.06%lu\n",
+	    (unsigned long)a->st_mtim.tv_sec,
+	    (unsigned long)a->st_mtim.tv_nsec,
+	    (unsigned long)b->st_mtim.tv_sec,
+	    (unsigned long)b->st_mtim.tv_nsec);
   return timespeccmp(&a->st_mtim, &b->st_mtim, >);
-#else
+}
+
+static void stab_mtimenow(struct stat *out) {
+  int r = clock_gettime(CLOCK_REALTIME, &out->st_mtim);
+  if (r) err(127,"(stage2) clock_gettime");
+  if (debugmode)
+    fprintf(stderr,"stab_mtimenow mtim %lu.%06lu\n",
+	    (unsigned long)out->st_mtim.tv_sec,
+	    (unsigned long)out->st_mtim.tv_nsec);
+}
+
+#else /* !defined(st_mtime) */
+
+static bool stab_isnewer(const struct stat *a, const struct stat *b) {
+  if (debugmode)
+    fprintf(stderr,"stab_isnewer mtime %lu %lu\n",
+	    (unsigned long)a->st_mtime,
+	    (unsigned long)b->st_mtime);
   return a->st_mtime > &b->st_mtime;
-#endif
 }
 
+static void stab_mtimenow(struct stat *out) {
+  out->st_mtime = time(NULL);
+  if (baseline_time.st_mtime == (time_t)-1) err(127,"(stage2) time()");
+  if (debugmode)
+    fprintf(stderr,"stab_mtimenow mtime %lu\n",
+	    (unsigned long)out->st_mtime);
+}
+
+#endif /* !defined(st_mtime) */
+
 static bool check_garbage_vs(const struct stat *started) {
   struct stat script_stab;
-  struct stat sock_stab;
   int r;
 
   r = lstat(script, &script_stab);
   if (r) err(127,"lstat script (%s)",script);
 
-  if (stab_isnewer(&script_stab, &sock_stab))
+  if (stab_isnewer(&script_stab, started))
     return 1;
 
   if (S_ISLNK(script_stab.st_mode)) {
     r = stat(script, &script_stab);
     if (r) err(127,"stat script (%s0",script);
 
-    if (stab_isnewer(&script_stab, &sock_stab))
+    if (stab_isnewer(&script_stab, started))
       return 1;
   }
 
@@ -417,6 +447,14 @@ static void make_stderr_copy(void) {
   if (stderr_copy < 0) err(127,"dup stderr (for copy for stage2)");
 }
 
+static void prep_stage2(void) {
+  int r;
+  
+  const char *stage2_val = m_asprintf("%d", stderr_copy);
+  r = setenv(STAGE2_VAR, stage2_val, 1);
+  if (r) err(127,"set %s (to announce to stage2)", STAGE2_VAR);
+}
+
 static void shbang_opts(const char *const **argv_io,
 			const struct cmdinfo *cmdinfos) {
   myopt(argv_io, cmdinfos);
@@ -434,16 +472,14 @@ static void queue_alarm(void);
 static void await_something(void);
 
 int main(int argc, const char *const *argv) {
-  const char *smashedopt, *us;
+  const char *smashedopt;
   int r;
 
-  us = argv[0];
-
-  if (argc>=4 && !strcmp(argv[1],"--stage2")) {
-    ++argv;
-    stage2 = 1;
+  stage2 = getenv(STAGE2_VAR);
+  if (stage2) {
+    int stderrfd = atoi(stage2);
+    assert(stderrfd>2);
 
-    int stderrfd = atoi(*++argv);
     r = dup2(stderrfd, 2);
     assert(r==2);
 
@@ -451,8 +487,6 @@ int main(int argc, const char *const *argv) {
     if (r<0) err(127,"open /dev/null as stdout");
     if (r>=3) close(r);
     else if (r!=1) errx(127,"open /dev/null for stdout gave bad fd %d",r);
-
-    socket_path = *++argv;
   }
 
   if (argc>=2 &&
@@ -510,13 +544,11 @@ int main(int argc, const char *const *argv) {
       tidy_garbage();
 
     make_stderr_copy();
+    prep_stage2();
 
     execlp("cgi-fcgi",
 	   "cgi-fcgi", "-connect", socket_path,
-	   us, "--stage2",
-	   m_asprintf("-c%d", check_interval),
-	   m_asprintf("%d", stderr_copy), socket_path,
-	   interp, script,
+	   script,
 	   (char*)0);
     err(127,"exec cgi-fcgi");
     
@@ -545,13 +577,7 @@ static pid_t script_child, stage2_pgrp;
 static bool out_of_date;
 
 static void record_baseline_time(void) {
-#ifdef st_mtime
-  int r = clock_gettime(CLOCK_REALTIME, &baseline_time.st_mtim);
-  if (r) err(127,"(stage2) clock_gettime");
-#else
-  baseline_time.st_mtime = time(NULL);
-  if (baseline_time.st_mtime == (time_t)-1) err(127,"(stage2) time()");
-#endif
+  stab_mtimenow(&baseline_time);
 }
 
 static void become_pgrp(void) {
@@ -654,6 +680,6 @@ static void await_something(void) {
   for (;;) {
     r = sigsuspend(&mask);
     assert(r==-1);
-    if (r != EINTR) err(127,"(stage2) sigsuspend");
+    if (errno != EINTR) err(127,"(stage2) sigsuspend");
   }
 }
-- 
2.30.2