initial commitHEADmaster

2 files changed, 140 insertions, 0 deletions

diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..7ea1a7b
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,23 @@
+CFLAGS += -Wall -Wpedantic
+LDFLAGS += -s
+
+PREFIX ?= ${HOME}
+BINDIR ?= ${PREFIX}/bin
+
+EXE != find . -name '*.c' | sed -e 's/\.c$$//' -e 's|^\./||'
+
+.PHONY: all install clean
+
+all: ${EXE}
+
+install: ${EXE}
+	install -d ${BINDIR}
+	@for e in ${EXE}; do echo install $$e ${BINDIR};\
+		install $$e ${BINDIR}; done
+
+uninstall:
+	@for e in ${EXE}; do echo rm -f ${BINDIR}/$$e;\
+		rm -f ${BINDIR}/$$e; done
+
+clean:
+	rm -fv ${EXE}
diff --git a/sudo.c b/sudo.c
new file mode 100644
index 0000000..2165ea8
--- /dev/null
+++ b/sudo.c
@@ -0,0 +1,117 @@
+/* sudo.c
+ * small wrapper to run "su root -c COMMAND" with proper escaping
+ */
+
+#include <err.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <ctype.h>
+
+/* string builders */
+
+typedef struct {
+	char *s;
+	int n, c;
+} StrBuilder;
+
+void
+sb_fit(StrBuilder *b, int n)
+{
+	if (n <= b->c) return;
+	b->c += !b->c;
+	while (b->c < n) b->c <<= 1;
+	b->s = realloc(b->s, b->c);
+	if (!b->s) err(1, "sb_fit");
+}
+
+void
+sb_cat(StrBuilder * restrict b, const char * restrict s)
+{
+	int sn = strlen(s);
+	sb_fit(b, b->n + sn);
+	memcpy(b->s + b->n, s, sn);
+	b->n += sn;
+}
+
+void
+sb_catc(StrBuilder *b, char c)
+{
+	sb_fit(b, b->n + 1);
+	b->s[b->n++] = c;
+}
+
+char
+*sb_str(StrBuilder *b)
+{
+	if (b->n == 0 || b->s[b->n-1] != '\0') {
+		sb_catc(b, '\0');
+		b->n--;
+	}
+	return b->s;
+}
+
+/* shell escape */
+
+#define SPECIAL "\"\\'#$`~{}*?[; "
+#define SPECIAL_DQUOT "\"\\`$"
+
+static inline int
+is(char c, const char *chr)
+{
+	while (*chr) {
+		if (c == *chr) return 1;
+		chr++;
+	}
+	return 0;
+}
+
+static inline int
+has(const char * restrict s, const char * restrict chr)
+{
+	while (*s) {
+		if (is(*s, chr)) return 1;
+		s++;
+	}
+	return 0;
+}
+
+void
+shell_esc(StrBuilder * restrict b, const char * restrict src)
+{
+	if (has(src, SPECIAL)) {
+		if (!isspace(*(unsigned char*)src) && src[1] == '\0') {
+			sb_catc(b, '\\');
+			sb_catc(b, src[0]);
+		} else if (strchr(src, '\'')) {
+			sb_catc(b, '"');
+			while (*src) {
+				if (is(*src, SPECIAL_DQUOT))
+					sb_catc(b, '\\');
+				sb_catc(b, *src++);
+			}
+			sb_catc(b, '"');
+		} else {
+			sb_catc(b, '\'');
+			sb_cat(b, src);
+			sb_catc(b, '\'');
+		}
+	} else {
+		sb_cat(b, src);
+	}
+}
+
+int
+main(int argc, const char **argv)
+{
+	StrBuilder b = { 0 };
+	for (int i = 1; i < argc; i++) {
+		if (i > 1)
+			sb_catc(&b, ' ');
+		shell_esc(&b, argv[i]);
+	}
+	execl("/usr/bin/su", "su", "root", "-c", sb_str(&b), NULL);
+	free(b.s);
+	return 0;
+}