diff --git a/Makefile b/Makefile
index ad366d9..185e987 100644
--- a/Makefile
+++ b/Makefile
@@ -16,10 +16,10 @@ ALLFLAGS=$(CFLAGS) $(CPPFLAGS) -I$(IDIR)
 
 LIBS=-lpam
 
-_DEPS = version.h log.h util.h ui.h ui_state.h config.h desktop.h auth.h ofield.h efield.h keys.h users.h sessions.h chvt.h macros.h launch_state.h
+_DEPS = version.h log.h util.h ui.h ui_state.h config.h desktop.h desktop_exec.h auth.h ofield.h efield.h keys.h users.h sessions.h chvt.h macros.h launch_state.h
 DEPS = $(patsubst %,$(IDIR)/%,$(_DEPS))
 
-_OBJ = main.o log.o util.o ui.o ui_state.o config.o desktop.o auth.o ofield.o efield.o users.o sessions.o chvt.o launch_state.o
+_OBJ = main.o log.o util.o ui.o ui_state.o config.o desktop.o desktop_exec.o auth.o ofield.o efield.o users.o sessions.o chvt.o launch_state.o
 OBJ = $(patsubst %,$(ODIR)/%,$(_OBJ))
 
 INFO_GIT_REV?=$$(git describe --long --tags --always || echo '?')
diff --git a/include/desktop_exec.h b/include/desktop_exec.h
new file mode 100644
index 0000000..2bc03e6
--- /dev/null
+++ b/include/desktop_exec.h
@@ -0,0 +1,7 @@
+#ifndef DESKTOP_EXEC_H_
+#define DESKTOP_EXEC_H_
+
+int parse_exec_string(const char* exec_s, int* arg_count, char*** args);
+void free_parsed_args(int arg_count, char** args);
+
+#endif
diff --git a/src/auth.c b/src/auth.c
index 83ee96b..1eae1d0 100644
--- a/src/auth.c
+++ b/src/auth.c
@@ -10,190 +10,13 @@
 
 #include "auth.h"
 #include "config.h"
+#include "desktop_exec.h"
+#include "log.h"
 #include "sessions.h"
 #include "ui.h"
 #include "unistd.h"
 #include "util.h"
 
-// constants for exec string parsing
-// ARG_LENGTH is the initial length of a parsed argument
-#define MAX_ARGS 100
-#define ARG_LENGTH 64
-
-// parse Exec=/bin/prog arg1 arg2\ with\ spaces
-void free_parsed_args(char** args, int arg_count) {
-  if (!args) return;
-  for (int i = 0; i < arg_count; i++) {
-    free(args[i]);
-  }
-  free((void*)args);
-}
-
-/* small closure-like struct to pass state to helper functions */
-struct ctx {
-  char** pcur;
-  size_t* pcur_len;
-  size_t* pcur_cap;
-  char*** pargv;
-  int* pargc;
-};
-/* append_char(state, ch) -> 0 on error, 1 on success */
-int append_char(struct ctx* st, char ch) {
-  char** pcur = st->pcur;
-  size_t* plen = st->pcur_len;
-  size_t* pcap = st->pcur_cap;
-  if (*plen + 1 >= *pcap) {
-    size_t newcap = *pcap ? (*pcap) * 2 : ARG_LENGTH;
-    char* cur = (char*)realloc(*pcur, newcap);
-    if (!cur) return 0;
-    *pcur = cur;
-    *pcap = newcap;
-  }
-  (*pcur)[(*plen)++] = ch;
-  return 1;
-}
-
-/* push_arg(state) -> 0 on error, 1 on success */
-int push_arg(struct ctx* st) {
-  char** pcur = st->pcur;
-  size_t* plen = st->pcur_len;
-  size_t* pcap = st->pcur_cap;
-  char*** pargv = st->pargv;
-  int* pargc = st->pargc;
-
-  if (*pargc > MAX_ARGS) {
-    return 1;
-  }
-  if (!*pcur) {
-    char* empty = strdup("");
-    if (!empty) return 0;
-    char** na = (char**)realloc((void*)*pargv, sizeof(char*) * ((*pargc) + 1));
-    if (!na) {
-      free(empty);
-      return 0;
-    }
-    *pargv = na;
-    (*pargv)[(*pargc)++] = empty;
-    return 1;
-  }
-  if (!append_char(st, '\0')) return 0;
-  char* final = (char*)realloc(*pcur, *plen);
-  if (!final) final = *pcur;
-  *pcur = NULL;
-  *plen = 0;
-  *pcap = 0;
-  char** na = (char**)realloc((void*)*pargv, sizeof(char*) * ((*pargc) + 1));
-  if (!na) {
-    free(final);
-    return 0;
-  }
-  *pargv = na;
-  (*pargv)[(*pargc)++] = final;
-  return 1;
-}
-
-/* Return codes:
-   0 = success
-   1 = bad args
-   2 = memory
-   3 = syntax
-
-  Important: call free_parsed_args afterwards to free the passed ***args
-*/
-// NOLINTBEGIN(readability-function-cognitive-complexity)
-int parse_exec_string(const char* exec_s, char*** args, int* arg_count) {
-  if (!exec_s || !args || !arg_count) return 1;
-  *args = NULL;
-  *arg_count = 0;
-
-  size_t len = strlen(exec_s);
-  size_t idx = 0;
-  char* cur = NULL;
-  size_t cur_len = 0;
-  size_t cur_cap = 0;
-  char** argv = NULL;
-  int argc = 0;
-  int in_quote = 0;
-
-  struct ctx ctx;
-  ctx.pcur = &cur;
-  ctx.pcur_len = &cur_len;
-  ctx.pcur_cap = &cur_cap;
-  ctx.pargv = &argv;
-  ctx.pargc = &argc;
-
-  while (idx < len) {
-    char cur_c = exec_s[idx];
-    if (!in_quote && (cur_c == ' ' || cur_c == '\t' || cur_c == '\n')) {
-      if (cur_cap) {
-        if (!push_arg(&ctx)) goto nomem;
-      }
-      idx++;
-      continue;
-    }
-    if (!in_quote && cur_c == '"') {
-      in_quote = 1;
-      idx++;
-      continue;
-    }
-    if (in_quote && cur_c == '"') {
-      in_quote = 0;
-      idx++;
-      continue;
-    }
-
-    if (cur_c == '\\') {
-      if (idx + 1 >= len) goto syntax_err;
-      if (!append_char(&ctx, exec_s[idx + 1])) goto nomem;
-      idx += 2;
-      continue;
-    }
-
-    if (cur_c == '%') {
-      if (idx + 1 >= len) goto syntax_err;
-      if (exec_s[idx + 1] == '%') {
-        if (!append_char(&ctx, '%')) goto nomem;
-        idx += 2;
-        continue;
-      }
-      /* drop any %X */
-      idx += 2;
-      continue;
-    }
-
-    if (!append_char(&ctx, cur_c)) goto nomem;
-    idx++;
-  }
-
-  if (in_quote) goto syntax_err;
-  if (cur_cap) {
-    if (!push_arg(&ctx)) goto nomem;
-  }
-  char** na = (char**)realloc((void*)argv, sizeof(char*) * (argc + 1));
-  if (!na) goto nomem;
-  argv = na;
-  argv[argc] = NULL;
-
-  *args = argv;
-  *arg_count = argc;
-  return 0;
-
-nomem:
-  if (cur) free(cur);
-  free_parsed_args(argv, argc);
-  *args = NULL;
-  *arg_count = 0;
-  return 2;
-
-syntax_err:
-  if (cur) free(cur);
-  free_parsed_args(argv, argc);
-  *args = NULL;
-  *arg_count = 0;
-  return 3;
-}
-// NOLINTEND(readability-function-cognitive-complexity)
-
 int pam_conversation(int num_msg, const struct pam_message** msg,
                      struct pam_response** resp, void* appdata_ptr) {
   struct pam_response* reply =
@@ -345,6 +168,22 @@ void moarEnv(char* user, struct session session, struct passwd* pw,
 // NOLINTBEGIN(readability-function-cognitive-complexity)
 bool launch(char* user, char* passwd, struct session session, void (*cb)(void),
             struct config* config) {
+  char** desktop_exec;
+  int desktop_count;
+
+  if (session.type != SHELL) {
+    desktop_exec = NULL;
+    int parse_status =
+        parse_exec_string(session.exec, &desktop_count, &desktop_exec);
+    if (parse_status != 0 || desktop_count == 0 || !desktop_exec[0]) {
+      print_err("failure parsing exec string");
+      log_printf("failure parsing exec string '%s': %d\n",
+                 session.exec ? session.exec : "NULL", parse_status);
+      free_parsed_args(desktop_count, desktop_exec);
+    }
+    return false;
+  }
+
   struct passwd* pw = getpwnam(user);
   if (pw == NULL) {
     print_err("could not get user info");
@@ -417,29 +256,20 @@ bool launch(char* user, char* passwd, struct session session, void (*cb)(void),
     *reach_session = true;
 
     // TODO: test existence of executable with TryExec
-    char** args = NULL;
-    int arg_count = 0;
-    int parse_status = parse_exec_string(session.exec, &args, &arg_count);
-    if (parse_status != 0 || arg_count == 0 || !args[0]) {
-      (void)fprintf(stderr, "failure parsing exec string '%s': %d\n",
-                    session.exec ? session.exec : "NULL", parse_status);
-      free_parsed_args(args, arg_count);
-      return false;
-    }
-
     printf("\x1b[0m");
     // NOLINTNEXTLINE(bugprone-branch-clone)
     if (session.type == SHELL) {
       clear_screen();
       (void)fflush(stdout);
-      execvp(args[0], args);
+      execlp(session.exec, session.exec, NULL);
     } else if (session.type == XORG || session.type == WAYLAND) {
       clear_screen();
       (void)fflush(stdout);
-      execvp(args[0], args);
+      // NOLINTNEXTLINE
+      free_parsed_args(desktop_count, desktop_exec);
+      execvp(desktop_exec[0], desktop_exec);
     }
-    free_parsed_args(args, arg_count);
-    perror("execl error");
+    perror("exec error");
     (void)fputs("failure calling session\n", stderr);
   } else {
     pid_t child_pid = (pid_t)pid;
diff --git a/src/desktop_exec.c b/src/desktop_exec.c
new file mode 100644
index 0000000..2774add
--- /dev/null
+++ b/src/desktop_exec.c
@@ -0,0 +1,183 @@
+#include <stddef.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "desktop_exec.h"
+
+// constants for exec string parsing
+#define MAX_ARGS 100
+// ARG_LENGTH is the initial length of a parsed argument
+#define ARG_LENGTH 64
+
+// parse Exec=/bin/prog arg1 arg2\ with\ spaces
+void free_parsed_args(int arg_count, char** args) {
+  if (!args) return;
+  for (int i = 0; i < arg_count; i++) {
+    free(args[i]);
+  }
+  free((void*)args);
+}
+
+/* small closure-like struct to pass state to helper functions */
+struct ctx {
+  char** pcur;
+  size_t* pcur_len;
+  size_t* pcur_cap;
+  char*** pargv;
+  int* pargc;
+};
+/* append_char(state, ch) -> 0 on error, 1 on success */
+int append_char(struct ctx* st, char ch) {
+  char** pcur = st->pcur;
+  size_t* plen = st->pcur_len;
+  size_t* pcap = st->pcur_cap;
+  if (*plen + 1 >= *pcap) {
+    size_t newcap = *pcap ? (*pcap) * 2 : ARG_LENGTH;
+    char* cur = (char*)realloc(*pcur, newcap);
+    if (!cur) return 0;
+    *pcur = cur;
+    *pcap = newcap;
+  }
+  (*pcur)[(*plen)++] = ch;
+  return 1;
+}
+
+/* push_arg(state) -> 0 on error, 1 on success */
+int push_arg(struct ctx* st) {
+  char** pcur = st->pcur;
+  size_t* plen = st->pcur_len;
+  size_t* pcap = st->pcur_cap;
+  char*** pargv = st->pargv;
+  int* pargc = st->pargc;
+
+  if (*pargc > MAX_ARGS) {
+    return 1;
+  }
+  if (!*pcur) {
+    char* empty = strdup("");
+    if (!empty) return 0;
+    char** na = (char**)realloc((void*)*pargv, sizeof(char*) * ((*pargc) + 1));
+    if (!na) {
+      free(empty);
+      return 0;
+    }
+    *pargv = na;
+    (*pargv)[(*pargc)++] = empty;
+    return 1;
+  }
+  if (!append_char(st, '\0')) return 0;
+  char* final = (char*)realloc(*pcur, *plen);
+  if (!final) final = *pcur;
+  *pcur = NULL;
+  *plen = 0;
+  *pcap = 0;
+  char** na = (char**)realloc((void*)*pargv, sizeof(char*) * ((*pargc) + 1));
+  if (!na) {
+    free(final);
+    return 0;
+  }
+  *pargv = na;
+  (*pargv)[(*pargc)++] = final;
+  return 1;
+}
+
+/* Return codes:
+   0 = success
+   1 = bad args
+   2 = memory
+   3 = syntax
+  Important: call free_parsed_args afterwards to free the passed ***args
+*/
+// NOLINTBEGIN(readability-function-cognitive-complexity)
+int parse_exec_string(const char* exec_s, int* arg_count, char*** args) {
+  if (!exec_s || !args || !arg_count) return 1;
+  *args = NULL;
+  *arg_count = 0;
+
+  size_t len = strlen(exec_s);
+  size_t idx = 0;
+  char* cur = NULL;
+  size_t cur_len = 0;
+  size_t cur_cap = 0;
+  char** argv = NULL;
+  int argc = 0;
+  int in_quote = 0;
+
+  struct ctx ctx;
+  ctx.pcur = &cur;
+  ctx.pcur_len = &cur_len;
+  ctx.pcur_cap = &cur_cap;
+  ctx.pargv = &argv;
+  ctx.pargc = &argc;
+
+  while (idx < len) {
+    char cur_c = exec_s[idx];
+    if (!in_quote && (cur_c == ' ' || cur_c == '\t' || cur_c == '\n')) {
+      if (cur_cap) {
+        if (!push_arg(&ctx)) goto nomem;
+      }
+      idx++;
+      continue;
+    }
+    if (!in_quote && cur_c == '"') {
+      in_quote = 1;
+      idx++;
+      continue;
+    }
+    if (in_quote && cur_c == '"') {
+      in_quote = 0;
+      idx++;
+      continue;
+    }
+
+    if (cur_c == '\\') {
+      if (idx + 1 >= len) goto syntax_err;
+      if (!append_char(&ctx, exec_s[idx + 1])) goto nomem;
+      idx += 2;
+      continue;
+    }
+
+    if (cur_c == '%') {
+      if (idx + 1 >= len) goto syntax_err;
+      if (exec_s[idx + 1] == '%') {
+        if (!append_char(&ctx, '%')) goto nomem;
+        idx += 2;
+        continue;
+      }
+      /* drop any %X */
+      idx += 2;
+      continue;
+    }
+
+    if (!append_char(&ctx, cur_c)) goto nomem;
+    idx++;
+  }
+
+  if (in_quote) goto syntax_err;
+  if (cur_cap) {
+    if (!push_arg(&ctx)) goto nomem;
+  }
+  char** na = (char**)realloc((void*)argv, sizeof(char*) * (argc + 1));
+  if (!na) goto nomem;
+  argv = na;
+  argv[argc] = NULL;
+
+  *args = argv;
+  *arg_count = argc;
+  return 0;
+
+nomem:
+  if (cur) free(cur);
+  free_parsed_args(argc, argv);
+  *args = NULL;
+  *arg_count = 0;
+  return 2;
+
+syntax_err:
+  if (cur) free(cur);
+  free_parsed_args(argc, argv);
+  *args = NULL;
+  *arg_count = 0;
+  return 3;
+}
+// NOLINTEND(readability-function-cognitive-complexity)