1 files changed, 75 insertions, 0 deletions
diff --git a/usr/klibc/execvpe.c b/usr/klibc/execvpe.c
new file mode 100644
index 0000000..0b844f2
--- /dev/null
+++ b/usr/klibc/execvpe.c
@@ -0,0 +1,75 @@
+/*
+ * execvpe.c
+ *
+ * execvpe() function (from which we build execlp, execlpe, execvp).
+ *
+ * This version of execvpe() will *not* spawn /bin/sh if the command
+ * return ENOEXEC.  That's what #! is for, folks!
+ *
+ * Since execlpe() and execvpe() aren't in POSIX, nor in glibc,
+ * I have followed QNX precedent in the implementation of the PATH:
+ * the PATH that is used is the one in the current environment, not
+ * in the new environment.  Otherwise it would be impossible to pass
+ * a different PATH to the new process than the one one would want to
+ * use to search.
+ */
+
+#include <errno.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <string.h>
+#include <limits.h>
+
+#define DEFAULT_PATH 	"/bin:/usr/bin:."
+
+int execvpe(const char *file, char *const *argv, char *const *envp)
+{
+	char path[PATH_MAX];
+	const char *searchpath, *esp;
+	size_t prefixlen, filelen, totallen;
+
+	if (strchr(file, '/'))	/* Specific path */
+		return execve(file, argv, envp);
+
+	filelen = strlen(file);
+
+	searchpath = getenv("PATH");
+	if (!searchpath)
+		searchpath = DEFAULT_PATH;
+
+	errno = ENOENT;		/* Default errno, if execve() doesn't
+				   change it */
+
+	do {
+		esp = strchr(searchpath, ':');
+		if (esp)
+			prefixlen = esp - searchpath;
+		else
+			prefixlen = strlen(searchpath);
+
+		if (prefixlen == 0 || searchpath[prefixlen - 1] == '/') {
+			totallen = prefixlen + filelen;
+			if (totallen >= PATH_MAX)
+				continue;
+			memcpy(path, searchpath, prefixlen);
+			memcpy(path + prefixlen, file, filelen);
+		} else {
+			totallen = prefixlen + filelen + 1;
+			if (totallen >= PATH_MAX)
+				continue;
+			memcpy(path, searchpath, prefixlen);
+			path[prefixlen] = '/';
+			memcpy(path + prefixlen + 1, file, filelen);
+		}
+		path[totallen] = '\0';
+
+		execve(path, argv, envp);
+		if (errno == E2BIG  || errno == ENOEXEC ||
+		    errno == ENOMEM || errno == ETXTBSY)
+			break;	/* Report this as an error, no more search */
+
+		searchpath = esp + 1;
+	} while (esp);
+
+	return -1;
+}