Extract function to determine executable directory from load_config so it can be used elsewhere

1 files changed, 74 insertions, 0 deletions

diff --git a/util.c b/util.c
index c41547a..0b8d8cb 100644
--- a/util.c
+++ b/util.c
@@ -3,6 +3,10 @@
 #include <stdio.h>
 #include <ctype.h>
 
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
 char * alloc_concat(char * first, char * second)
 {
 	int flen = strlen(first);
@@ -63,3 +67,73 @@ char * split_keyval(char * text)
 	*text = 0;
 	return text+1;
 }
+
+static char * exe_str;
+
+void set_exe_str(char * str)
+{
+	exe_str = str;
+}
+
+char * readlink_alloc(char * path)
+{
+	char * linktext = NULL;
+	ssize_t linksize = 512;
+	ssize_t cursize = 0;
+	do {
+		if (linksize > cursize) {
+			cursize = linksize;
+			if (linktext) {
+				free(linktext);
+			}
+		}
+		linktext = malloc(cursize);
+		linksize = readlink(path, linktext, cursize-1);
+		if (linksize == -1) {
+			perror("readlink");
+			free(linktext);
+			linktext = NULL;
+		}
+	} while (linksize > cursize);
+	return linktext;
+}
+
+char * get_exe_dir()
+{
+	static char * exe_dir;
+	if (!exe_dir) {
+		char * linktext = readlink_alloc("/proc/self/exe");
+		if (!linktext) {
+			goto fallback;
+		}
+		char * cur;
+		int linksize = strlen(linktext);
+		for(cur = linktext + linksize - 1; cur != linktext; cur--)
+		{
+			if (*cur == '/') {
+				*cur = 0;
+				break;
+			}
+		}
+		if (cur == linktext) {
+			free(linktext);
+fallback:
+			if (!exe_str) {
+				fputs("/proc/self/exe is not available and set_exe_str was not called!", stderr);
+			}
+			int pathsize = strlen(exe_str);
+			for(cur = exe_str + pathsize - 1; cur != exe_str; cur--)
+			{
+				if (*cur == '/') {
+					exe_dir = malloc(cur-exe_str+1);
+					memcpy(exe_dir, exe_str, cur-exe_str);
+					exe_dir[cur-exe_str] = 0;
+					break;
+				}
+			}
+		} else {
+			exe_dir = linktext;
+		}
+	}
+	return exe_dir;
+}