From bdd970fe719f78ba0b13446190ede748e3f8fb4d Mon Sep 17 00:00:00 2001
From: Laurent Bercot <ska-skaware@skarnet.org>
Date: Sat, 18 Jun 2016 18:11:53 +0000
Subject:  Revert backtick to a non-wrapper; add -I to backtick and withstdinas

---
 doc/backtick.html              |  27 +++++----
 doc/withstdinas.html           |  27 +++++----
 package/deps.mak               |   4 +-
 src/execline/backtick.c        | 132 +++++++++++++++++++++++------------------
 src/execline/deps-exe/backtick |   1 +
 src/execline/withstdinas.c     |  54 ++++++-----------
 6 files changed, 129 insertions(+), 116 deletions(-)

diff --git a/doc/backtick.html b/doc/backtick.html
index 6aa2f01..694a29d 100644
--- a/doc/backtick.html
+++ b/doc/backtick.html
@@ -46,20 +46,27 @@ output as a value. </li>
 <h2> Options </h2>
 
 <ul>
- <li> <tt>-i</tt>&nbsp;: insist. If <em>prog1</em> crashes or exits non-zero,
-<tt>backtick</tt> exits with an
-<a href="exitcodes.html">approximation</a> of the same exit code. </li>
- <li> <tt>-D&nbsp;<em>default</em></tt>&nbsp;: default value. If
-<em>prog1</em> crashes or exits non-zero, <em>default</em> is used as
-<em>variable</em>'s value. If neither the <tt>-i</tt> nor the <tt>-D</tt>
-option have been given, <tt>backtick</tt> execs into
-<em>prog2...</em> no matter what <em>prog1</em> does, with the null word as
-<em>variable</em>'s value if <em>prog1</em> didn't write anything before
-dying. </li>
  <li> <tt>-n</tt>&nbsp;: chomp an ending newline off <em>prog1...</em>'s
 output. </li>
 </ul>
 
+<p>
+ The other options tell backtick what to do if <em>prog1...</em>'s output
+is not suitable as the contents of an environment variable, i.e. it
+contains a null character:
+</p>
+
+<ul>
+ <li> <tt>-i</tt>&nbsp;: backtick exits 1. </li>
+ <li> <tt>-I</tt>&nbsp;: <em>variable</em> is <strong>removed</strong> from
+the environment, and execution proceeds. </li>
+ <li> <tt>-D&nbsp;<em>default</em></tt>&nbsp;: the value of <em>variable</em>
+is set to <em>default</em>, and execution proceeds. </li>
+ <li> neither of those options: the value of <em>variable</em> is set to whatever
+the start of <em>prog1...</em>'s output is, up to the first null character;
+then execution proceeds. </li>
+</ul>
+
 <h2> Notes </h2>
 
 <ul>
diff --git a/doc/withstdinas.html b/doc/withstdinas.html
index 29ad1b6..db49681 100644
--- a/doc/withstdinas.html
+++ b/doc/withstdinas.html
@@ -31,7 +31,7 @@ environment variable.
 </p>
 
 <pre>
-     withstdinas [ -i | -D <em>default</em> ] [ -n ] <em>variable</em> <em>prog...</em>
+     withstdinas [ -i | -I | -D <em>default</em> ] [ -n ] <em>variable</em> <em>prog...</em>
 </pre>
 
 <ul>
@@ -44,18 +44,25 @@ environment variable.
 <h2> Options </h2>
 
 <ul>
- <li> <tt>-i</tt>&nbsp;: insist. If the data on stdin is invalid as
-an environment variable, for instance if it contains a null
-character, <tt>withstdinas</tt> exits 1. </li>
- <li> <tt>-D&nbsp;<em>default</em></tt>&nbsp;: default value.
-If the data on stdin is invalid, <em>default</em> is used as
-<em>variable</em>'s value. If neither the <tt>-i</tt> nor the <tt>-D</tt>
-option have been given, <tt>withstdinas</tt> execs into
-<em>prog...</em> with <em>variable</em> containing whatever value could be read on stdin,
-cut before the first null character. </li>
  <li> <tt>-n</tt>&nbsp;: chomp an ending newline off stdin. </li>
 </ul>
 
+<p>
+ The other options tell withstdinas what to do if its input is
+not suitable as the contents of an environment variable, i.e. it
+contains a null character:
+</p>
+
+<ul>
+ <li> <tt>-i</tt>&nbsp;: withstdinas exits 1. </li>
+ <li> <tt>-I</tt>&nbsp;: <em>variable</em> is <strong>removed</strong> from
+the environment, and execution proceeds. </li>
+ <li> <tt>-D&nbsp;<em>default</em></tt>&nbsp;: the value of <em>variable</em>
+is set to <em>default</em>, and execution proceeds. </li>
+ <li> neither of those options:  the value of <em>variable</em> is set to whatever the
+start of the input is, up to the first null character; and execution proceeds. </li>
+</ul>
+
 <h2> Notes </h2>
 
 <ul>
diff --git a/package/deps.mak b/package/deps.mak
index d38609f..88138b3 100644
--- a/package/deps.mak
+++ b/package/deps.mak
@@ -3,7 +3,7 @@
 #
 
 src/execline/background.o src/execline/background.lo: src/execline/background.c src/include/execline/execline.h
-src/execline/backtick.o src/execline/backtick.lo: src/execline/backtick.c src/include/execline/config.h src/include/execline/execline.h
+src/execline/backtick.o src/execline/backtick.lo: src/execline/backtick.c src/include/execline/execline.h
 src/execline/cd.o src/execline/cd.lo: src/execline/cd.c
 src/execline/define.o src/execline/define.lo: src/execline/define.c src/include-local/exlsn.h
 src/execline/dollarat.o src/execline/dollarat.lo: src/execline/dollarat.c
@@ -75,7 +75,7 @@ src/libexecline/exlsn_multidefine.o src/libexecline/exlsn_multidefine.lo: src/li
 background: EXTRA_LIBS :=
 background: src/execline/background.o ${LIBEXECLINE} -lskarnet
 backtick: EXTRA_LIBS :=
-backtick: src/execline/backtick.o -lskarnet
+backtick: src/execline/backtick.o ${LIBEXECLINE} -lskarnet
 cd: EXTRA_LIBS :=
 cd: src/execline/cd.o -lskarnet
 define: EXTRA_LIBS :=
diff --git a/src/execline/backtick.c b/src/execline/backtick.c
index 2deb9f3..2661983 100644
--- a/src/execline/backtick.c
+++ b/src/execline/backtick.c
@@ -1,84 +1,102 @@
 /* ISC license. */
 
+#include <sys/types.h>
+#include <sys/wait.h>
 #include <unistd.h>
-#include <errno.h>
-#include <skalibs/uint.h>
+#include <skalibs/bytestr.h>
 #include <skalibs/sgetopt.h>
 #include <skalibs/strerr2.h>
+#include <skalibs/stralloc.h>
 #include <skalibs/djbunix.h>
-#include <execline/config.h>
 #include <execline/execline.h>
 
-#define USAGE "backtick [ -i | -D default ] [ -n ] var { prog... } command..."
+#define USAGE "backtick [ -i | -I | -D default ] [ -n ] var { prog... } remainder..."
 #define dieusage() strerr_dieusage(100, USAGE)
 
-int main (int argc, char const *const *argv, char const *const *envp)
+int main (int argc, char const **argv, char const *const *envp)
 {
-  char const *def = 0 ;
+  subgetopt_t localopt = SUBGETOPT_ZERO ;
+  pid_t pid ;
+  int argc1, fdwstat ;
+  stralloc modif = STRALLOC_ZERO ;
+  unsigned int modifstart ;
   int insist = 0, chomp = 0 ;
+  char const *def = 0 ;
   PROG = "backtick" ;
+  for (;;)
   {
-    subgetopt_t l = SUBGETOPT_ZERO ;
-    for (;;)
+    register int opt = subgetopt_r(argc, argv, "iInD:", &localopt) ;
+    if (opt < 0) break ;
+    switch (opt)
     {
-      register int opt = subgetopt_r(argc, argv, "eniD:", &l) ;
-      if (opt == -1) break ;
-      switch (opt)
-      {
-	case 'e' : break ; /* compat */
-        case 'n' : chomp = 1 ; break ;
-        case 'i' : insist = 1 ; break ;
-        case 'D' : def = l.arg ; break ;
-        default : dieusage() ;
-      }
+      case 'i' : insist = 2 ; break ;
+      case 'I' : insist = 1 ; break ;
+      case 'n' : chomp = 1 ; break ;
+      case 'D' : def = localopt.arg ; break ;
+      default : dieusage() ;
     }
-    argc -= l.ind ; argv += l.ind ;
   }
+  argc -= localopt.ind ; argv += localopt.ind ;
+
   if (argc < 2) dieusage() ;
-  if (!argv[0][0]) dieusage() ;
-  if (!argv[1][0]) strerr_dief1x(100, "empty block") ;
+  if (!*argv[0]) strerr_dief1x(100, "empty variable not accepted") ;
+  if (!stralloc_cats(&modif, argv[0]) || !stralloc_catb(&modif, "=", 1))
+    strerr_diefu1sys(111, "stralloc_catb") ;
+  modifstart = modif.len ;
+  argc-- ; argv++ ;
+  argc1 = el_semicolon(argv) ;
+  if (!argc1) strerr_dief1x(100, "empty block") ;
+  if (argc1 >= argc) strerr_dief1x(100, "unterminated block") ;
+
+  argv[argc1] = 0 ;
+  pid = child_spawn1_pipe(argv[0], argv, envp, &fdwstat, 1) ;
+  if (!pid) strerr_diefu2sys(111, "spawn ", argv[0]) ;
+  if (!slurp(&modif, fdwstat)) strerr_diefu1sys(111, "slurp") ;
+  close(fdwstat) ;
+  if (wait_pid(pid, &fdwstat) < 0) strerr_diefu1sys(111, "wait_pid") ;
+
+  if (wait_status(fdwstat))
   {
-    unsigned int m = 0, i = 1 ;
-    int fd = dup(0) ;
-    char const *newargv[argc + 15] ;
-    char fmt[UINT_FMT] ;
-    if (fd < 0)
+    if (insist >= 2)
+      if (WIFSIGNALED(fdwstat)) strerr_dief1x(111, "child process crashed") ;
+      else strerr_dief1x(WEXITSTATUS(fdwstat), "child process exited non-zero") ;
+    else if (insist)
     {
-      if (errno != EBADF) strerr_diefu1sys(111, "dup stdin") ;
+      modif.len = modifstart - 1 ;
+      chomp = 0 ;
     }
-    else fmt[uint_fmt(fmt, (unsigned int)fd)] = 0 ;
-    newargv[m++] = EXECLINE_BINPREFIX "pipeline" ;
-    newargv[m++] = "--" ;
-    while (argv[i] && argv[i][0] != EXECLINE_BLOCK_END_CHAR && (!EXECLINE_BLOCK_END_CHAR || (argv[i][0] && argv[i][1])))
-      newargv[m++] = argv[i++] ;
-    if (!argv[i]) strerr_dief1x(100, "unterminated block") ;
-    newargv[m++] = "" ; i++ ;
-    if (!argv[i]) strerr_dief1x(100, "empty remainder") ;
-    newargv[m++] = EXECLINE_BINPREFIX "withstdinas" ;
-    if (insist) newargv[m++] = "-i" ;
-    if (chomp) newargv[m++] = "-n" ;
-    if (def)
+    else if (def)
     {
-      newargv[m++] = "-D" ;
-      newargv[m++] = def ;
+      modif.len = modifstart ;
+      if (!stralloc_cats(&modif, def)) strerr_diefu1sys(111, "stralloc_catb") ;
     }
-    newargv[m++] = "-!" ;
-    newargv[m++] = "--" ;
-    newargv[m++] = argv[0] ;
-    if (fd < 0)
-    {
-      newargv[m++] = EXECLINE_BINPREFIX "fdclose" ;
-      newargv[m++] = "0" ;
-    }
-    else
+  }
+  if (argc == argc1 - 1) return 0 ;
+  if (!stralloc_0(&modif)) strerr_diefu1sys(111, "stralloc_catb") ;
+  {
+    unsigned int reallen = str_len(modif.s) ;
+    if (reallen < modif.len - 1)
     {
-      newargv[m++] = EXECLINE_BINPREFIX "fdmove" ;
-      newargv[m++] = "0" ;
-      newargv[m++] = fmt ;
+      if (insist >= 2)
+        strerr_dief1x(1, "child process output contained a null character") ;
+      else if (insist)
+      {
+        modif.len = modifstart ;
+        modif.s[modif.len - 1] = 0 ;
+        chomp = 0 ;
+      }
+      else if (def)
+      {
+        modif.len = modifstart ;
+        if (!stralloc_catb(&modif, def, str_len(def)+1))
+          strerr_diefu1sys(111, "stralloc_catb") ;
+        strerr_warnw2x("child process output contained a null character", " - using default instead") ;
+      }
+      else modif.len = reallen + 1 ;
     }
-    while (argv[i]) newargv[m++] = argv[i++] ;
-    newargv[m++] = 0 ;
-    pathexec_run(newargv[0], newargv, envp) ;
-    strerr_dieexec(111, newargv[0]) ;
+    if (chomp && (modif.s[modif.len - 2] == '\n'))
+      modif.s[--modif.len - 1] = 0 ;
   }
+  pathexec_r(argv + argc1 + 1, envp, env_len(envp), modif.s, modif.len) ;
+  strerr_dieexec(111, argv[argc1 + 1]) ;
 }
diff --git a/src/execline/deps-exe/backtick b/src/execline/deps-exe/backtick
index e7187fe..97021b5 100644
--- a/src/execline/deps-exe/backtick
+++ b/src/execline/deps-exe/backtick
@@ -1 +1,2 @@
+${LIBEXECLINE}
 -lskarnet
diff --git a/src/execline/withstdinas.c b/src/execline/withstdinas.c
index c1e3c36..af7140f 100644
--- a/src/execline/withstdinas.c
+++ b/src/execline/withstdinas.c
@@ -10,7 +10,7 @@
 #include <skalibs/stralloc.h>
 #include <skalibs/djbunix.h>
 
-#define USAGE "withstdinas [ -i | -D default ] [ -n ] var remainder..."
+#define USAGE "withstdinas [ -i | -I | -D default ] [ -n ] var remainder..."
 #define dieusage() strerr_dieusage(100, USAGE)
 
 int main (int argc, char const **argv, char const *const *envp)
@@ -18,19 +18,19 @@ int main (int argc, char const **argv, char const *const *envp)
   subgetopt_t localopt = SUBGETOPT_ZERO ;
   stralloc modif = STRALLOC_ZERO ;
   unsigned int modifstart ;
-  int insist = 0, chomp = 0, reapit = 0 ;
+  int insist = 0, chomp = 0 ;
   char const *def = 0 ;
   PROG = "withstdinas" ;
   for (;;)
   {
-    register int opt = subgetopt_r(argc, argv, "einD:!", &localopt) ;
+    register int opt = subgetopt_r(argc, argv, "iInD:", &localopt) ;
     if (opt < 0) break ;
     switch (opt)
     {
-      case 'i' : insist = 1 ; break ;
+      case 'i' : insist = 2 ; break ;
+      case 'I' : insist = 1 ; break ;
       case 'n' : chomp = 1 ; break ;
       case 'D' : def = localopt.arg ; break ;
-      case '!' : reapit = 1 ; break ;
       default : dieusage() ;
     }
   }
@@ -38,42 +38,23 @@ int main (int argc, char const **argv, char const *const *envp)
 
   if (!argc) dieusage() ;
   if (!*argv[0] || strchr(argv[0], '=')) strerr_dief1x(100, "invalid variable name") ;
-  if (!stralloc_catb(&modif, "!", 2)
-   || !stralloc_cats(&modif, argv[0])
-   || !stralloc_catb(&modif, "=", 1))
+  if (!stralloc_cats(&modif, argv[0]) || !stralloc_catb(&modif, "=", 1))
     strerr_diefu1sys(111, "stralloc_catb") ;
   modifstart = modif.len ;
   if (!slurp(&modif, 0)) strerr_diefu1sys(111, "slurp") ;
-  if (reapit)
-  {
-    char const *x = env_get2(envp, "!") ;
-    if (x)
-    {
-      uint64 pid ;
-      int wstat ;
-      if (!uint640_scan(x, &pid)) strerr_dieinvalid(100, "!") ;
-      if (waitpid(pid, &wstat, 0) < 0)
-        strerr_diefu1sys(111, "waitpid") ;
-      if (wait_estatus(wstat))
-      {
-        if (insist)
-          if (WIFSIGNALED(wstat)) strerr_dief1x(wait_estatus(wstat), "child process crashed") ;
-          else strerr_dief1x(wait_estatus(wstat), "child process exited non-zero") ;
-        else if (def)
-        {
-          modif.len = modifstart ;
-          if (!stralloc_cats(&modif, def)) strerr_diefu1sys(111, "stralloc_catb") ;
-        }
-      }
-    }
-  }
   if (!stralloc_0(&modif)) strerr_diefu1sys(111, "stralloc_catb") ;
   {
-    unsigned int reallen = str_len(modif.s + 2) ;
-    if (reallen < modif.len - 3)
+    unsigned int reallen = str_len(modif.s) ;
+    if (reallen < modif.len - 1)
     {
-      if (insist)
+      if (insist >= 2)
         strerr_dief1x(1, "stdin contained a null character") ;
+      else if (insist)
+      {
+        modif.len = modifstart ;
+        modif.s[modif.len - 1] = 0 ;
+        chomp = 0 ;
+      }
       else if (def)
       {
         modif.len = modifstart ;
@@ -81,13 +62,12 @@ int main (int argc, char const **argv, char const *const *envp)
           strerr_diefu1sys(111, "stralloc_catb") ;
         strerr_warnw2x("stdin contained a null character", " - using default instead") ;
       }
-      else
-        modif.len = reallen + 3 ;
+      else modif.len = reallen + 1 ;
     }
     if (chomp && (modif.s[modif.len - 2] == '\n'))
       modif.s[--modif.len - 1] = 0 ;
   }
   if (!argv[1]) return 0 ;
-  pathexec_r(argv + 1, envp, env_len(envp), modif.s + !reapit * 2, modif.len - !reapit * 2) ;
+  pathexec_r(argv + 1, envp, env_len(envp), modif.s, modif.len) ;
   strerr_dieexec(111, argv[1]) ;
 }
-- 
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