| -rw-r--r-- | shared.c | 71 |
1 files changed, 71 insertions, 0 deletions
@@ -414,12 +414,83 @@ int readfile(const char *path, char **buf, size_t *size) } 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; +} |