From: Ken Hornstein <kenh@pobox.com>
Date: Fri, 18 Jan 2013 21:03:26 +0000 (-0500)
Subject: Beginning of implementation of new argsplit() function to handle arguments
X-Git-Url: https://diplodocus.org/git/nmh/commitdiff_plain/78211e93e9a370556c7c44b204dfac7b47766b43?hp=-c

Beginning of implementation of new argsplit() function to handle arguments
to profile-defined commands.
---

78211e93e9a370556c7c44b204dfac7b47766b43
diff --git a/Makefile.am b/Makefile.am
index 0fbf441a..b79e930d 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -472,7 +472,8 @@ uninstall-hook:
 ##
 ## Our rules to build our internal libraries (libmh.a, libmts.a)
 ##
-sbr_libmh_a_SOURCES = sbr/addrsbr.c sbr/ambigsw.c sbr/atooi.c sbr/base64.c \
+sbr_libmh_a_SOURCES = sbr/addrsbr.c sbr/ambigsw.c sbr/atooi.c sbr/arglist.c \
+		      sbr/base64.c \
 		      sbr/brkstring.c sbr/check_charset.c sbr/client.c \
 		      sbr/closefds.c sbr/concat.c sbr/context_del.c \
 		      sbr/context_find.c sbr/context_foil.c sbr/context_read.c \
diff --git a/sbr/arglist.c b/sbr/arglist.c
new file mode 100644
index 00000000..20bf84c7
--- /dev/null
+++ b/sbr/arglist.c
@@ -0,0 +1,124 @@
+
+/*
+ * arglist.c -- Routines for handling argument lists for execvp() and friends
+ *
+ * This code is Copyright (c) 2013, by the authors of nmh.  See the
+ * COPYRIGHT file in the root directory of the nmh distribution for
+ * complete copyright information.
+ */
+
+#include <h/mh.h>
+#include <h/utils.h>
+
+/*
+ * Split up a command into an appropriate array to pass to execvp()
+ * or similar function.  Returns an allocated argv[] array.
+ *
+ * Function arguments:
+ *
+ * command - String to split up
+ * file    - the first argument to "command", suitable for the first argument
+ *           to execvp().  Returns allocated memory that must be free()d.
+ * argp    - Index to last element (NULL) of returned argv[] array.
+ *
+ * Our basic algorithm is this:
+ *
+ * - If there are no spaces or shell metacharacters in "command", then
+ *   take it as-is.
+ * - If there are spaces in command, space-split command string and
+ *   append an argument list to it.
+ * - If we have shell metacharacters, run the command using
+ *   /bin/sh -c 'command "${@}"'.
+ *
+ * In all cases additional arguments can be added to the argv[] array.
+ */
+
+/* Shell metacharacters we use to trigger a call to the shell */
+
+#define METACHARS	"$&*(){}[]'\";\\|?<>~`\n"
+
+char **
+argsplit(char *command, char **file, int *argp)
+{
+    char **argvarray, *p;
+    int space = 0, metachar = 0, i;
+
+    for (p = command; *p; p++) {
+    	if (*p == ' ' || *p == '\t') {
+		space = 1;
+	} else if (strchr(METACHARS, *p)) {
+		metachar = 1;
+		break;
+	}
+    }
+
+    argvarray = (char **) mh_xmalloc((sizeof(char **) * MAXARGS));
+
+    /*
+     * The simple case - no spaces or shell metacharacters
+     */
+
+    if (!space && !metachar) {
+    	argvarray[0] = getcpy(r1bindex(command, '/'));
+	argvarray[1] = NULL;
+	*file = getcpy(command);
+	if (argp)
+	    *argp = 1;
+	return argvarray;
+    }
+
+    /*
+     * Spaces, but no shell metacharacters; space-split into seperate
+     * arguments
+     */
+
+    if (space && !metachar) {
+    	char **split;
+	p = getcpy(command);
+	split = brkstring(p, " \t", NULL);
+	if (split[0] == NULL) {
+	    adios(NULL, "Invalid blank command found");
+	}
+	argvarray[0] = getcpy(r1bindex(split[0], '/'));
+	for (i = 1; split[i] != NULL; i++) {
+	    if (i > MAXARGS) {
+		adios(NULL, "Command exceeded argument limit");
+	    }
+	    argvarray[i] = getcpy(split[i]);
+	}
+	argvarray[i] = NULL;
+	*file = getcpy(split[0]);
+	if (argp)
+	    *argp = i;
+	return argvarray;
+    }
+
+    /*
+     * Remaining option - pass to the shell.
+     *
+     * Some notes here:
+     *
+     * - The command passed to "sh -c" is actually:
+     *      command "$@"
+     *
+     *   If there are additional arguments they will be expanded by the
+     *   shell, otherwise "$@" expands to nothing.
+     *
+     * - Every argument after the -c string gets put into positional
+     *   parameters starting at $0, but $@ starts expanding with $1.
+     *   So we put in a dummy argument (we just use /bin/sh)
+     */
+
+    *file = getcpy("/bin/sh");
+    argvarray[0] = getcpy("sh");
+    argvarray[1] = getcpy("-c");
+    argvarray[2] = getcpy(command);
+    argvarray[2] = add(" \"$@\"", argvarray[2]);
+    argvarray[3] = getcpy("/bin/sh");
+    argvarray[4] = NULL;
+
+    if (argp)
+    	*argp = 4;
+
+    return argvarray;
+}