1 files changed, 121 insertions, 0 deletions
diff --git a/src/pathexec.c b/src/pathexec.c
new file mode 100644
index 0000000..564d65d
--- /dev/null
+++ b/src/pathexec.c
@@ -0,0 +1,121 @@
+#include <unistd.h>
+#include "alloc.h"
+#include "error.h"
+#include "stralloc.h"
+#include "str.h"
+#include "byte.h"
+#include "env.h"
+#include "pathexec.h"
+
+/**
+  * @file pathexec.c
+  * @author djb
+  * @ref ucspi-tcp, ucspi-ssl
+  * @brief populate environment after fork
+  */
+
+static stralloc plus;
+static stralloc tmp;
+
+int pathexec_env(const char *s,const char *t)
+{
+  if (!s) return 1;
+  if (!stralloc_copys(&tmp,s)) return 0;
+  if (t) {
+    if (!stralloc_cats(&tmp,"=")) return 0;
+    if (!stralloc_cats(&tmp,t)) return 0;
+  }
+  if (!stralloc_0(&tmp)) return 0;
+  return stralloc_cat(&plus,&tmp);
+}
+
+int pathexec_multienv(stralloc *sa)
+{
+  if (!sa) return 1;
+  return stralloc_cat(&plus,sa);
+}
+
+void pathexec(char * const *argv)
+{
+  char **e;
+  unsigned int elen;
+  unsigned int i;
+  unsigned int j;
+  unsigned int split;
+  unsigned int t;
+
+  if (!stralloc_cats(&plus,"")) return;
+
+  elen = 0;
+  for (i = 0; environ[i]; ++i)
+    ++elen;
+  for (i = 0; i < plus.len; ++i)
+    if (!plus.s[i])
+      ++elen;
+
+  e = (char **) alloc((elen + 1) * sizeof(char *));
+  if (!e) return;
+
+  elen = 0;
+  for (i = 0; environ[i]; ++i)
+    e[elen++] = environ[i];
+
+  j = 0;
+  for (i = 0; i < plus.len; ++i)
+    if (!plus.s[i]) {
+      split = str_chr(plus.s + j,'=');
+      for (t = 0; t < elen; ++t)
+        if (byte_equal(plus.s + j,split,e[t]))
+          if (e[t][split] == '=') {
+            --elen;
+            e[t] = e[elen];
+            break;
+          }
+      if (plus.s[j + split])
+        e[elen++] = plus.s + j;
+      j = i + 1;
+    }
+  e[elen] = 0;
+
+  pathexec_run(*argv,argv,e);
+  alloc_free(e);
+}
+
+void pathexec_run(const char *file,char *const *argv,char *const *envp)
+{
+  char *path;
+  unsigned int split;
+  int savederrno;
+
+  if (file[str_chr(file,'/')]) {
+    execve(file,argv,envp);
+    return;
+  }
+
+  path = env_get("PATH");
+  if (!path) path = "/bin:/usr/bin";
+
+  savederrno = 0;
+  for (;;) {
+    split = str_chr(path,':');
+    if (!stralloc_copyb(&tmp,path,split)) return;
+    if (!split)
+      if (!stralloc_cats(&tmp,".")) return;
+    if (!stralloc_cats(&tmp,"/"))  return;
+    if (!stralloc_cats(&tmp,file)) return;
+    if (!stralloc_0(&tmp)) return;
+
+    execve(tmp.s,argv,envp);
+    if (errno != ENOENT) {
+      savederrno = errno;
+      if ((errno != EACCES) && (errno != EPERM) && (errno != EISDIR)) return;
+    }
+
+    if (!path[split]) {
+      if (savederrno) errno = savederrno;
+      return;
+    }
+    path += split;
+    path += 1;
+  }
+}