pschdir(1): add source file

src/pschdir.c

@@ -0,0 +1,30 @@
+#include <errno.h> /* EACCESS, ELOOP, ENAMETOOLONG, ENOENT, ENOTDIR, errno */
+#include <stdio.h> /* fprintf(3), stderr */
+#include <string.h> /* strerror(3) */
+#include <sysexits.h> /* EX_OSERR, EX_NOPERM, EX_NOINPUT, EX_UNAVAILABLE,
+                       * EX_USAGE */
+#include <unistd.h> /* chdir(2) */
+
+char *program_name = "pschdir";
+
+int main(int argc, char *argv[]){
+	if (argc < 3) {
+		fprintf(stderr, "Usage: %s [directory] [command (argument...)]\n",
+			argv[0] == NULL ? program_name : argv[0]);
+		return EX_USAGE;
+	}
+
+	if(chdir(argv[1]) != 0){
+		fprintf(stderr, "%s: %s: %s\n", argv[0], argv[1], strerror(errno));
+
+		switch (errno) {
+			case ENAMETOOLONG:	return EX_OSERR;
+			case EACCES:      	return EX_NOPERM;
+			case ENOENT:
+			case ENOTDIR:     	return EX_NOINPUT;
+			default:          	return EX_UNAVAILABLE;
+		}
+	}
+
+	execvp(argv[2], &argv[2]);
+}