Merge branch 'bw/spawn-via-shell-path'

"sh" on the user's PATH may be utterly broken on some systems;
consistently use SHELL_PATH even from inside run-command API.

By Ben Walton
* bw/spawn-via-shell-path:
  Use SHELL_PATH from build system in run_command.c:prepare_shell_cmd

Makefile

@@ -1849,6 +1849,13 @@ DEFAULT_PAGER_CQ_SQ = $(subst ','\'',$(DEFAULT_PAGER_CQ))
 BASIC_CFLAGS += -DDEFAULT_PAGER='$(DEFAULT_PAGER_CQ_SQ)'
 endif
 
+ifdef SHELL_PATH
+SHELL_PATH_CQ = "$(subst ",\",$(subst \,\\,$(SHELL_PATH)))"
+SHELL_PATH_CQ_SQ = $(subst ','\'',$(SHELL_PATH_CQ))
+
+BASIC_CFLAGS += -DSHELL_PATH='$(SHELL_PATH_CQ_SQ)'
+endif
+
 ALL_CFLAGS += $(BASIC_CFLAGS)
 ALL_LDFLAGS += $(BASIC_LDFLAGS)
 

run-command.c

@@ -4,6 +4,10 @@
 #include "sigchain.h"
 #include "argv-array.h"
 
+#ifndef SHELL_PATH
+# define SHELL_PATH "/bin/sh"
+#endif
+
 struct child_to_clean {
 	pid_t pid;
 	struct child_to_clean *next;
@@ -90,7 +94,7 @@ static const char **prepare_shell_cmd(const char **argv)
 		die("BUG: shell command is empty");
 
 	if (strcspn(argv[0], "|&;<>()$`\\\"' \t\n*?[#~=%") != strlen(argv[0])) {
-		nargv[nargc++] = "sh";
+		nargv[nargc++] = SHELL_PATH;
 		nargv[nargc++] = "-c";
 
 		if (argc < 2)