[PATCH] Make sq_expand() available as sq_quote().

A useful shell safety helper sq_expand() was hidden as a static
function in diff.c.  Extract it out and make it available as
sq_quote().

Signed-off-by: Junio C Hamano <junkio@cox.net>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/Makefile b/Makefile
index d613a8c..6e90d8f 100644 (file)
--- a/Makefile
+++ b/Makefile
@@ -65,6 +65,9 @@ LIB_H=cache.h object.h blob.h tree.h commit.h tag.h delta.h epoch.h csum-file.h
 LIB_H += strbuf.h
 LIB_OBJS += strbuf.o
 
+LIB_H += quote.h
+LIB_OBJS += quote.o 
+
 LIB_H += diff.h count-delta.h
 LIB_OBJS += diff.o diffcore-rename.o diffcore-pickaxe.o diffcore-pathspec.o \
        count-delta.o diffcore-break.o diffcore-order.o

diff --git a/diff.c b/diff.c
index a720290..36bbda6 100644 (file)
--- a/diff.c
+++ b/diff.c
@@ -5,6 +5,7 @@
 #include <sys/wait.h>
 #include <signal.h>
 #include "cache.h"
+#include "quote.h"
 #include "diff.h"
 #include "diffcore.h"
 
@@ -40,42 +41,6 @@ static const char *external_diff(void)
        return external_diff_cmd;
 }
 
-/* Help to copy the thing properly quoted for the shell safety.
- * any single quote is replaced with '\'', and the caller is
- * expected to enclose the result within a single quote pair.
- *
- * E.g.
- *  original     sq_expand     result
- *  name     ==> name      ==> 'name'
- *  a b      ==> a b       ==> 'a b'
- *  a'b      ==> a'\''b    ==> 'a'\''b'
- */
-static char *sq_expand(const char *src)
-{
-       static char *buf = NULL;
-       int cnt, c;
-       const char *cp;
-       char *bp;
-
-       /* count bytes needed to store the quoted string. */
-       for (cnt = 1, cp = src; *cp; cnt++, cp++)
-               if (*cp == '\'')
-                       cnt += 3;
-
-       buf = xmalloc(cnt);
-       bp = buf;
-       while ((c = *src++)) {
-               if (c != '\'')
-                       *bp++ = c;
-               else {
-                       bp = strcpy(bp, "'\\''");
-                       bp += 4;
-               }
-       }
-       *bp = 0;
-       return buf;
-}
-
 static struct diff_tempfile {
        const char *name; /* filename external diff should read from */
        char hex[41];
@@ -167,16 +132,16 @@ static void builtin_diff(const char *name_a,
                         int complete_rewrite)
 {
        int i, next_at, cmd_size;
-       const char *diff_cmd = "diff -L'%s%s' -L'%s%s'";
-       const char *diff_arg  = "'%s' '%s'||:"; /* "||:" is to return 0 */
+       const char *diff_cmd = "diff -L%s%s -L%s%s";
+       const char *diff_arg  = "%s %s||:"; /* "||:" is to return 0 */
        const char *input_name_sq[2];
        const char *path0[2];
        const char *path1[2];
        const char *name_sq[2];
        char *cmd;
 
-       name_sq[0] = sq_expand(name_a);
-       name_sq[1] = sq_expand(name_b);
+       name_sq[0] = sq_quote(name_a);
+       name_sq[1] = sq_quote(name_b);
 
        /* diff_cmd and diff_arg have 6 %s in total which makes
         * the sum of these strings 12 bytes larger than required.
@@ -186,7 +151,7 @@ static void builtin_diff(const char *name_a,
        cmd_size = (strlen(diff_cmd) + strlen(diff_opts) +
                        strlen(diff_arg) - 9);
        for (i = 0; i < 2; i++) {
-               input_name_sq[i] = sq_expand(temp[i].name);
+               input_name_sq[i] = sq_quote(temp[i].name);
                if (!strcmp(temp[i].name, "/dev/null")) {
                        path0[i] = "/dev/null";
                        path1[i] = "";

diff --git a/quote.c b/quote.c
new file mode 100644 (file)
index 0000000..5e6fda3
--- /dev/null
+++ b/quote.c
@@ -0,0 +1,41 @@
+#include "cache.h"
+#include "quote.h"
+
+/* Help to copy the thing properly quoted for the shell safety.
+ * any single quote is replaced with '\'', and the caller is
+ * expected to enclose the result within a single quote pair.
+ *
+ * E.g.
+ *  original     sq_quote     result
+ *  name     ==> name      ==> 'name'
+ *  a b      ==> a b       ==> 'a b'
+ *  a'b      ==> a'\''b    ==> 'a'\''b'
+ */
+char *sq_quote(const char *src)
+{
+       static char *buf = NULL;
+       int cnt, c;
+       const char *cp;
+       char *bp;
+
+       /* count bytes needed to store the quoted string. */
+       for (cnt = 3, cp = src; *cp; cnt++, cp++)
+               if (*cp == '\'')
+                       cnt += 3;
+
+       buf = xmalloc(cnt);
+       bp = buf;
+       *bp++ = '\'';
+       while ((c = *src++)) {
+               if (c != '\'')
+                       *bp++ = c;
+               else {
+                       bp = strcpy(bp, "'\\''");
+                       bp += 4;
+               }
+       }
+       *bp++ = '\'';
+       *bp = 0;
+       return buf;
+}
+

diff --git a/quote.h b/quote.h
new file mode 100644 (file)
index 0000000..c8cfb3a
--- /dev/null
+++ b/quote.h
@@ -0,0 +1,26 @@
+#ifndef QUOTE_H
+#define QUOTE_H
+
+
+/* Help to copy the thing properly quoted for the shell safety.
+ * any single quote is replaced with '\'', and the whole thing
+ * is enclosed in a single quote pair.
+ *
+ * For example, if you are passing the result to system() as an
+ * argument:
+ *
+ * sprintf(cmd, "foobar %s %s", sq_quote(arg0), sq_quote(arg1))
+ *
+ * would be appropriate.  If the system() is going to call ssh to
+ * run the command on the other side:
+ *
+ * sprintf(cmd, "git-diff-tree %s %s", sq_quote(arg0), sq_quote(arg1));
+ * sprintf(rcmd, "ssh %s %s", sq_quote(host), sq_quote(cmd));
+ *
+ * Note that the above examples leak memory!  Remember to free result from
+ * sq_quote() in a real application.
+ */
+
+char *sq_quote(const char *src);
+
+#endif