1 files changed, 71 insertions, 0 deletions

diff --git a/shared.c b/shared.c
index 5f46793..76d26dd 100644
--- a/shared.c
+++ b/shared.c
@@ -402,24 +402,95 @@ int cgit_close_filter(struct cgit_filter *filter)
 int readfile(const char *path, char **buf, size_t *size)
 {
         int fd, e;
         struct stat st;
 
         fd = open(path, O_RDONLY);
         if (fd == -1)
                 return errno;
         if (fstat(fd, &st)) {
                 e = errno;
                 close(fd);
                 return e;
         }
         if (!S_ISREG(st.st_mode)) {
                 close(fd);
                 return EISDIR;
         }
         *buf = xmalloc(st.st_size + 1);
         *size = read_in_full(fd, *buf, st.st_size);
         e = errno;
         (*buf)[*size] = '\0';
         close(fd);
         return (*size == st.st_size ? 0 : e);
 }
+
+int is_token_char(char c)
+{
+        return isalnum(c) || c == '_';
+}
+
+/* Replace name with getenv(name), return pointer to zero-terminating char
+ */
+char *expand_macro(char *name, int maxlength)
+{
+        char *value;
+        int len;
+
+        len = 0;
+        value = getenv(name);
+        if (value) {
+                len = strlen(value);
+                if (len > maxlength)
+                        len = maxlength;
+                strncpy(name, value, len);
+        }
+        return name + len;
+}
+
+#define EXPBUFSIZE (1024 * 8)
+
+/* Replace all tokens prefixed by '$' in the specified text with the
+ * value of the named environment variable.
+ * NB: the return value is a static buffer, i.e. it must be strdup'd
+ * by the caller.
+ */
+char *expand_macros(const char *txt)
+{
+        static char result[EXPBUFSIZE];
+        char *p, *start;
+        int len;
+
+        p = result;
+        start = NULL;
+        while (p < result + EXPBUFSIZE - 1 && txt && *txt) {
+                *p = *txt;
+                if (start) {
+                        if (!is_token_char(*txt)) {
+                                if (p - start > 0) {
+                                        *p = '\0';
+                                        len = result + EXPBUFSIZE - start - 1;
+                                        p = expand_macro(start, len) - 1;
+                                }
+                                start = NULL;
+                                txt--;
+                        }
+                        p++;
+                        txt++;
+                        continue;
+                }
+                if (*txt == '$') {
+                        start = p;
+                        txt++;
+                        continue;
+                }
+                p++;
+                txt++;
+        }
+        *p = '\0';
+        if (start && p - start > 0) {
+                len = result + EXPBUFSIZE - start - 1;
+                p = expand_macro(start, len);
+                *p = '\0';
+        }
+        return result;
+}