Implemented execvp() for real.

git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@24560 a95241bf-73f2-0310-859d-f6bbb57e9c96

src/system/libroot/posix/unistd/Jamfile

@@ -10,7 +10,7 @@ MergeObject posix_unistd.o :
 	conf.c
 	directory.c
 	dup.c
-	exec.c
+	exec.cpp
 	_exit.c
 	fcntl.c
 	fork.c

src/system/libroot/posix/unistd/exec.cpp

@@ -4,15 +4,16 @@
  */
 
 
-#include <syscalls.h>
 #include <libroot_private.h>
+#include <syscalls.h>
 
-#include <unistd.h>
-#include <errno.h>
 #include <alloca.h>
-#include <stdio.h>
+#include <errno.h>
 #include <stdarg.h>
+#include <stdio.h>
 #include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
 
 
 static int
@@ -47,16 +48,19 @@ copy_arguments(va_list list, const char **args, const char *arg)
 }
 
 
-//	#pragma mark -
-
-
-int
-execve(const char *path, char * const args[], char * const environment[])
+static int
+do_exec(const char *path, char * const args[], char * const environment[],
+	bool useDefaultInterpreter)
 {
 	int32 argCount = 0, envCount = 0;
 	char invoker[B_FILE_NAME_LENGTH];
 	char **newArgs = NULL;
 
+	if (path == NULL) {
+		errno = B_BAD_VALUE;
+		return -1;
+	}
+
 	// count argument/environment list entries here, we don't want
 	// to do this in the kernel
 	while (args[argCount] != NULL)
@@ -71,30 +75,29 @@ execve(const char *path, char * const args[], char * const environment[])
 	}
 
 	// test validity of executable + support for scripts
-	{
-		status_t status = __test_executable(path, invoker);
+	status_t status = __test_executable(path, invoker);
+	if (status < B_OK) {
+		if (status == B_NOT_AN_EXECUTABLE && useDefaultInterpreter) {
+			strcpy(invoker, "/bin/sh");
+			status = B_OK;
+		} else {
+			errno = status;
+			return -1;
+		}
+	}
+
+	if (invoker[0] != '\0') {
+		status = __parse_invoke_line(invoker, &newArgs, &args, &argCount, path);
 		if (status < B_OK) {
 			errno = status;
 			return -1;
 		}
 
-		if (invoker[0]) {
-			status = __parse_invoke_line(invoker, &newArgs, &args, &argCount, path);
-			if (status < B_OK) {
-				errno = status;
-				return -1;
-			}
-
-			path = newArgs[0];
-		}
+		path = newArgs[0];
 	}
 
-	// "argv[0]" and "path" should be identical here, but they don't have
-	// to. Instead of worrying and needing to copy the array, we just
-	// don't care and pass everything to the kernel - it will have to
-	// do the right thing :)
-
-	errno = _kern_exec(path, argCount, newArgs ? newArgs : args, envCount, environment);
+	errno = _kern_exec(path, argCount, newArgs ? newArgs : args, envCount,
+		environment);
 		// if this call returns, something definitely went wrong
 
 	free(newArgs);
@@ -102,18 +105,75 @@ execve(const char *path, char * const args[], char * const environment[])
 }
 
 
+//	#pragma mark -
+
+
 int
-execv(const char *path, char * const *argv)
+execve(const char *path, char* const args[], char* const environment[])
 {
-	return execve(path, argv, environ);
+	return do_exec(path, args, environment, false);
 }
 
 
 int
-execvp(const char *file, char * const *argv)
+execv(const char *path, char * const *argv)
 {
-	// ToDo: do the "p" thing
-	return execve(file, argv, environ);
+	return do_exec(path, argv, environ, false);
+}
+
+
+int
+execvp(const char *file, char* const* argv)
+{
+	// let do_exec() handle cases where file is a path (or invalid)
+	if (file == NULL || strchr(file, '/') != NULL)
+		return do_exec(file, argv, environ, true);
+
+	// file is just a leaf name, so we have to look it up in the path
+
+	// get the PATH
+	const char* paths = getenv("PATH");
+	if (paths == NULL) {
+		errno = B_ENTRY_NOT_FOUND;
+		return -1;
+	}
+
+	int fileNameLen = strlen(file);
+
+	// iterate through the paths
+	while (true) {
+		const char* pathEnd = strchr(paths, ':');
+		int pathLen = (pathEnd ? pathEnd - paths : strlen(paths));
+
+		// We skip empty paths and those that would become too long.
+		// The latter is not really correct, but practically irrelevant.
+		if (pathLen == 0
+			|| pathLen + 1 + fileNameLen >= B_PATH_NAME_LENGTH) {
+			continue;
+		}
+
+		// concatinate the program path
+		char path[B_PATH_NAME_LENGTH];
+		memcpy(path, paths, pathLen);
+		path[pathLen] = '\0';
+
+		if (path[pathLen - 1] != '/')
+			strcat(path, "/");
+		strcat(path, file);
+
+		// if executable, execute it
+		if (access(path, X_OK) == 0)
+			return do_exec(path, argv, environ, true);
+
+		// not found yet -- get the next path, if any
+		if (pathEnd == NULL)
+			break;
+
+        paths = pathEnd + 1;
+	}
+
+	errno = B_ENTRY_NOT_FOUND;
+	return -1;
 }
 
 
@@ -132,12 +192,12 @@ execl(const char *path, const char *arg, ...)
 
 	// copy arguments
 
-	args = alloca((count + 1) * sizeof(char *));
+	args = (const char**)alloca((count + 1) * sizeof(char *));
 	va_start(list, arg);
 	copy_arguments(list, args, arg);
 	va_end(list);
 
-	return execve(path, (char * const *)args, environ);
+	return do_exec(path, (char * const *)args, environ, false);
 }
 
 
@@ -156,7 +216,7 @@ execlp(const char *file, const char *arg, ...)
 
 	// copy arguments
 
-	args = alloca((count + 1) * sizeof(char *));
+	args = (const char**)alloca((count + 1) * sizeof(char *));
 	va_start(list, arg);
 	copy_arguments(list, args, arg);
 	va_end(list);
@@ -181,12 +241,12 @@ execle(const char *path, const char *arg, ... /*, char **env */)
 
 	// copy arguments
 
-	args = alloca((count + 1) * sizeof(char *));
+	args = (const char**)alloca((count + 1) * sizeof(char *));
 	va_start(list, arg);
 	copy_arguments(list, args, arg);
 	va_end(list);
 
-	return execve(path, (char * const *)args, env);
+	return do_exec(path, (char * const *)args, env, false);
 }