Infrastructure, first drop of toy shell, and a bit of work on df.

1 files changed, 65 insertions, 0 deletions

diff --git a/lib/functions.c b/lib/functions.c
new file mode 100644
index 00000000..3d9a8aca
--- /dev/null
+++ b/lib/functions.c
@@ -0,0 +1,65 @@
+/* vi: set ts=4 :*/
+/* functions.c - reusable stuff.
+ *
+ * Functions with the x prefix never return failure, they either succeed or
+ * kill the program with an error message.
+ */
+
+#include "toys.h"
+
+// Die with an error message.
+void error_exit(char *msg, ...)
+{
+	va_list args;
+
+	va_start(args, msg);
+	fprintf(stderr, "%s: ", toys.which->name);
+	vfprintf(stderr, msg, args);
+	va_end(args);
+	exit(toys.exitval);
+}
+
+void strlcpy(char *dest, char *src, size_t size)
+{
+	strncpy(dest,src,size);
+	dest[size-1] = 0;
+}
+
+// Die unless we can allocate memory.
+void *xmalloc(size_t size)
+{
+	void *ret = malloc(size);
+	if (!ret) error_exit("xmalloc");
+}
+
+// Die unless we can copy this string.
+void *xstrndup(char *s, size_t n)
+{
+	void *ret = xmalloc(++n);
+	strlcpy(ret, s, n);
+	
+	return ret;
+}
+
+// Die unless we can exec argv[]
+void *xexec(char **argv)
+{
+	execvp(argv[0], argv);
+	error_exit("No %s", argv[0]);
+}
+
+// Die unless we can open/create a file, returning file descriptor.
+int xopen(char *path, int flags, int mode)
+{
+	int fd = open(path, flags, mode);
+	if (fd == -1) error_exit("No file %s\n", path);
+	return fd;
+}
+
+// Die unless we can open/create a file, returning FILE *.
+FILE *xfopen(char *path, char *mode)
+{
+	FILE *f = fopen(path, mode);
+	if (!f) error_exit("No file %s\n", path);
+	return f;
+}