1 files changed, 76 insertions, 0 deletions
diff --git a/src/execline/background.c b/src/execline/background.c
new file mode 100644
index 0000000..d3e96ff
--- /dev/null
+++ b/src/execline/background.c
@@ -0,0 +1,76 @@
+/* ISC license. */
+
+#include <sys/types.h>
+#include <unistd.h>
+#ifdef EXECLINE_OLD_VARNAMES
+#include <skalibs/bytestr.h>
+#endif
+#include <skalibs/sgetopt.h>
+#include <skalibs/strerr2.h>
+#include <skalibs/env.h>
+#include <skalibs/djbunix.h>
+#include <skalibs/uint64.h>
+#include <execline/execline.h>
+
+#define USAGE "background [ -d ] { command... }"
+
+int main (int argc, char const **argv, char const *const *envp)
+{
+  pid_t pid ;
+  int argc1 ;
+  int df = 0 ;
+  PROG = "background" ;
+  {
+    subgetopt_t l = SUBGETOPT_ZERO ;
+    for (;;)
+    {
+      register int opt = subgetopt_r(argc, argv, "d", &l) ;
+      if (opt == -1) break ;
+      switch (opt)
+      {
+        case 'd' : df = 1 ; break ;
+        default : strerr_dieusage(100, USAGE) ;
+      }
+    }
+    argc -= l.ind ; argv += l.ind ;
+  }
+  argc1 = el_semicolon(argv) ;
+  if (!argc1) strerr_dief1x(100, "empty block") ;
+  if (argc1 >= argc) strerr_dief1x(100, "unterminated block") ;
+  if (argc1 + 1 == argc) df = 0 ;
+  argv[argc1] = 0 ;
+
+  if (df)
+  {
+    pid = doublefork() ;
+    switch (pid)
+    {
+      case -1: strerr_diefu1sys(111, "doublefork") ;
+      case 0:
+        PROG = "background (grandchild)" ;
+        pathexec0_run(argv, envp) ;
+        strerr_dieexec(127, argv[0]) ;
+    }
+  }
+  else
+  {
+    pid = el_spawn0(argv[0], argv, envp) ;
+    if (!pid) strerr_diefu2sys(111, "spawn ", argv[0]) ;
+  }
+  if (argc1 + 1 == argc) return 0 ;
+  {
+#ifdef EXECLINE_OLD_VARNAMES
+    char fmt[UINT64_FMT * 2 + 10] = "!=" ;
+#else
+    char fmt[UINT64_FMT + 2] = "!=" ;
+#endif
+    register unsigned int i = 2 ;
+    i += uint64_fmt(fmt+i, (uint64)pid) ; fmt[i++] = 0 ;
+#ifdef EXECLINE_OLD_VARNAMES
+    byte_copy(fmt+i, 8, "LASTPID=") ; i += 8 ;
+    i += uint64_fmt(fmt+i, (uint64)pid) ; fmt[i++] = 0 ;
+#endif
+    pathexec_r(argv + argc1 + 1, envp, env_len(envp), fmt, i) ;
+  }
+  strerr_dieexec(111, argv[argc1+1]) ;
+}