[WIP] Add instances

still need to do the following:

- check if the folder exists

- try and find some way to canonicalize the path name

1 files changed, 157 insertions, 0 deletions

diff --git a/src/launcherutil.c b/src/launcherutil.c
new file mode 100644
index 0000000..8df4a71
--- /dev/null
+++ b/src/launcherutil.c
@@ -0,0 +1,157 @@
+#include "macros.h"
+#include "l2su.h"
+
+#include <stdlib.h>
+#include <string.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <errno.h>
+#include <sys/stat.h>
+
+/* handcoded string functions
+ *
+ * NOTE: I am aware that this is inefficient but since these are used only a handful of times
+ * during initialization, I don't think performance is really a huge deal here.
+ *
+ * remember that this is a Minecraft launcher, so the PC has to meet the minimum specs of that,
+ * which are well above the minimum specs of this launcher */
+
+char *l2_launcher_strapp(char *buf, const char *src)
+{
+  size_t buflen = strlen(buf);
+  size_t srclen = strlen(src);
+
+  char *ret = realloc(buf, buflen + srclen + 1);
+  if (!ret) return NULL;
+
+  memcpy(ret + buflen, src, srclen);
+  ret[buflen + srclen] = '\0'; /* realloc does not initialize like calloc does */
+
+  return ret;
+}
+
+char *l2_launcher_find_config_path(void)
+{
+  /* check for $L2SU_CONFIG */
+  char *config = getenv(PROJECT_NAME_UPPER "_CONFIG");
+  if (config) {
+    return strdup(config);
+  }
+  
+  /* check for $XDG_CONFIG_HOME */
+  config = getenv("XDG_CONFIG_HOME");
+  if (config) {
+    /* want to append '"/" PROJECT_NAME' to our string */
+    char *ret = strdup(config);
+    if (!ret) return NULL;
+
+    return l2_launcher_strapp(ret, "/" PROJECT_NAME);
+  }
+
+  /* check for $HOME/.config */
+  config = getenv("HOME");
+  if (config) {
+    char *ret = strdup(config);
+    if (!ret) return NULL;
+
+    return l2_launcher_strapp(ret, "/.config/" PROJECT_NAME);
+  }
+
+  /* fail (do NOT attempt to find home directory from passwd */
+  return NULL;
+}
+
+char *l2_launcher_find_data_path(void)
+{
+  /* check for $L2SU_DATA */
+  char *config = getenv(PROJECT_NAME_UPPER "_DATA");
+  if (config) {
+    return strdup(config);
+  }
+
+  /* check for $XDG_DATA_HOME */
+  config = getenv("XDG_DATA_HOME");
+  if (config) {
+    char *ret = strdup(config);
+    if (!ret) return NULL;
+
+    return l2_launcher_strapp(ret, "/" PROJECT_NAME);
+  }
+
+  /* check for $HOME/.local/share */
+  config = getenv("HOME");
+  if (config) {
+    char *ret = strdup(config);
+    if (!ret) return NULL;
+
+    return l2_launcher_strapp(ret, "/.local/share/" PROJECT_NAME);
+  }
+
+  return NULL;
+}
+
+int l2_launcher_open_config(const char *path, int flags, mode_t mode)
+{
+  int conffd = open(l2_state.paths.config, O_RDONLY | O_DIRECTORY);
+  if (conffd < 0) return INSTANCE_ERRNO;
+
+  int instfd = openat(conffd, path, flags, mode);
+  int en = errno; /* back up errno because close can fail */
+
+  close(conffd);
+
+  errno = en;
+  return instfd;
+}
+
+/* NOTE: There's no portable (or otherwise - see open(2) BUGS) way to do this without race conditions. */
+int l2_launcher_mkdir_parents(const char *path)
+{
+  if (*path != '/') return -1;
+
+  int reserrno = 0;
+
+  char *pathbuf = strdup(path);
+  char *pcurelem = pathbuf;
+  if (!pathbuf) return -1;
+
+  struct stat stbuf = { 0 };
+
+  do { /* strtok is off-limits because it smells bad */
+    *pcurelem = '/';
+    pcurelem = strchr(pcurelem + 1, '/');
+
+    if (pcurelem) {
+      *pcurelem = '\0';
+    }
+
+    /* now pathbuf contains our truncated path name which may or may not exist */
+    if (mkdir(pathbuf, 0755) < 0) {
+      if (errno == EEXIST) {
+        /* racy: stat the file and continue if it is a directory */
+        if (stat(pathbuf, &stbuf) < 0) {
+          reserrno = errno;
+          goto mdcleanup;
+        }
+
+        if (!S_ISDIR(stbuf.st_mode)) {
+          reserrno = ENOTDIR;
+          goto mdcleanup;
+        }
+      } else {
+        reserrno = errno;
+        goto mdcleanup;
+      }
+    }
+  } while (pcurelem);
+
+mdcleanup:
+
+  free(pathbuf);
+  if (reserrno != 0) {
+    errno = reserrno;
+    return -1;
+  }
+
+  return 0;
+}