Add path_manip function

2 files changed, 56 insertions, 0 deletions

diff --git a/include/utils.h b/include/utils.h
index 4ade817..2756347 100644
--- a/include/utils.h
+++ b/include/utils.h
@@ -30,6 +30,10 @@
 #define STASIS_XML_PRETTY_PRINT_PROG "xmllint"
 #define STASIS_XML_PRETTY_PRINT_ARGS "--format"
 
+#define PM_APPEND 1 << 0
+#define PM_PREPEND 1 << 1
+#define PM_ONCE  1 << 2
+
 /**
  * Change directory. Push path on directory stack.
  *
@@ -392,4 +396,13 @@ int mkdirs(const char *_path, mode_t mode);
  */
 char *find_version_spec(char *package_name);
 
+/**
+* Manipulate the PATH environment variable
+* @param path to insert (does not need to exist)
+* @param mode PM_APPEND `$path:$PATH`
+* @param mode PM_PREPEND `$PATH:path`
+* @param mode PM_ONCE do not manipulate if `path` is present in PATH variable
+*/
+int path_manip(char *path, int mode);
+
 #endif //STASIS_UTILS_H
diff --git a/src/lib/core/utils.c b/src/lib/core/utils.c
index 5f0807c..793b445 100644
--- a/src/lib/core/utils.c
+++ b/src/lib/core/utils.c
@@ -808,3 +808,46 @@ int mkdirs(const char *_path, mode_t mode) {
 char *find_version_spec(char *str) {
     return strpbrk(str, "@~=<>!");
 }
+
+int path_manip(char *path, int mode) {
+    if (isempty(path)) {
+        SYSERROR("%s", "New PATH element cannot be zero-length or NULL");
+        return -1;
+    }
+
+    const char *system_path_old = getenv("PATH");
+    if (!system_path_old) {
+        SYSERROR("%s", "Unable to read PATH");
+        return -1;
+    }
+
+    char *system_path_new = NULL;
+
+    if (mode & PM_APPEND) {
+        asprintf(&system_path_new, "%s:%s", system_path_old, path);
+    } else if (mode & PM_PREPEND) {
+        asprintf(&system_path_new, "%s:%s", path, system_path_old);
+    }
+
+    if (!system_path_new) {
+        SYSERROR("%s", "Unable to allocate memory to update PATH");
+        return -1;
+    }
+
+    if (mode & PM_ONCE) {
+        if (!strstr(system_path_old, path)) {
+            guard_free(system_path_new);
+            return 0;
+        }
+    }
+
+    if (setenv("PATH", system_path_new, 1) < 0) {
+        SYSERROR("Unable to prepend to PATH: %s", path);
+        guard_free(system_path_new);
+        return -1;
+    }
+
+    guard_free(system_path_new);
+    return 0;
+}
+