/*-
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* Copyright (c) 1991, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/types.h>
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#include <sys/uio.h>
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#include <errno.h>
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#include <limits.h>
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#include <paths.h>
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#include <stdarg.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include "private/__bionic_get_shell_path.h"
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#include "private/FdPath.h"
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extern "C" char** environ;
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enum ExecVariant { kIsExecL, kIsExecLE, kIsExecLP };
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static int __execl(const char* name, const char* argv0, ExecVariant variant, va_list ap) {
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// Count the arguments.
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va_list count_ap;
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va_copy(count_ap, ap);
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size_t n = 1;
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while (va_arg(count_ap, char*) != nullptr) {
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++n;
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}
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va_end(count_ap);
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// Construct the new argv.
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char* argv[n + 1];
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argv[0] = const_cast<char*>(argv0);
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n = 1;
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while ((argv[n] = va_arg(ap, char*)) != nullptr) {
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++n;
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}
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// Collect the argp too.
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char** argp = (variant == kIsExecLE) ? va_arg(ap, char**) : environ;
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va_end(ap);
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return (variant == kIsExecLP) ? execvp(name, argv) : execve(name, argv, argp);
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}
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int execl(const char* name, const char* arg, ...) {
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va_list ap;
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va_start(ap, arg);
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int result = __execl(name, arg, kIsExecL, ap);
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va_end(ap);
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return result;
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}
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int execle(const char* name, const char* arg, ...) {
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va_list ap;
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va_start(ap, arg);
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int result = __execl(name, arg, kIsExecLE, ap);
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va_end(ap);
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return result;
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}
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int execlp(const char* name, const char* arg, ...) {
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va_list ap;
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va_start(ap, arg);
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int result = __execl(name, arg, kIsExecLP, ap);
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va_end(ap);
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return result;
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}
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int execv(const char* name, char* const* argv) {
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return execve(name, argv, environ);
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}
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int execvp(const char* name, char* const* argv) {
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return execvpe(name, argv, environ);
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}
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static int __exec_as_script(const char* buf, char* const* argv, char* const* envp) {
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size_t arg_count = 1;
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while (argv[arg_count] != nullptr) ++arg_count;
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const char* script_argv[arg_count + 2];
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script_argv[0] = "sh";
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script_argv[1] = buf;
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memcpy(script_argv + 2, argv + 1, arg_count * sizeof(char*));
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return execve(__bionic_get_shell_path(), const_cast<char**>(script_argv), envp);
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}
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int execvpe(const char* name, char* const* argv, char* const* envp) {
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// Do not allow null name.
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if (name == nullptr || *name == '\0') {
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errno = ENOENT;
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return -1;
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}
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// If it's an absolute or relative path name, it's easy.
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if (strchr(name, '/') && execve(name, argv, envp) == -1) {
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if (errno == ENOEXEC) return __exec_as_script(name, argv, envp);
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return -1;
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}
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// Get the path we're searching.
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const char* path = getenv("PATH");
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if (path == nullptr) path = _PATH_DEFPATH;
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// Make a writable copy.
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size_t len = strlen(path) + 1;
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char writable_path[len];
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memcpy(writable_path, path, len);
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bool saw_EACCES = false;
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// Try each element of $PATH in turn...
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char* strsep_buf = writable_path;
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const char* dir;
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while ((dir = strsep(&strsep_buf, ":"))) {
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// It's a shell path: double, leading and trailing colons
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// mean the current directory.
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if (*dir == '\0') dir = const_cast<char*>(".");
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size_t dir_len = strlen(dir);
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size_t name_len = strlen(name);
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char buf[dir_len + 1 + name_len + 1];
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mempcpy(mempcpy(mempcpy(buf, dir, dir_len), "/", 1), name, name_len + 1);
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execve(buf, argv, envp);
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switch (errno) {
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case EISDIR:
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case ELOOP:
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case ENAMETOOLONG:
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case ENOENT:
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case ENOTDIR:
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break;
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case ENOEXEC:
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return __exec_as_script(buf, argv, envp);
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case EACCES:
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saw_EACCES = true;
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break;
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default:
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return -1;
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}
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}
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if (saw_EACCES) errno = EACCES;
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return -1;
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}
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int fexecve(int fd, char* const* argv, char* const* envp) {
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// execveat with AT_EMPTY_PATH (>= 3.19) seems to offer no advantages.
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execve(FdPath(fd).c_str(), argv, envp);
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if (errno == ENOENT) errno = EBADF;
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return -1;
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}
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