v4.19.13 snapshot.
diff --git a/tools/lib/subcmd/run-command.c b/tools/lib/subcmd/run-command.c
new file mode 100644
index 0000000..5cdac21
--- /dev/null
+++ b/tools/lib/subcmd/run-command.c
@@ -0,0 +1,229 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <string.h>
+#include <linux/string.h>
+#include <errno.h>
+#include <sys/wait.h>
+#include "subcmd-util.h"
+#include "run-command.h"
+#include "exec-cmd.h"
+
+#define STRERR_BUFSIZE 128
+
+static inline void close_pair(int fd[2])
+{
+ close(fd[0]);
+ close(fd[1]);
+}
+
+static inline void dup_devnull(int to)
+{
+ int fd = open("/dev/null", O_RDWR);
+ dup2(fd, to);
+ close(fd);
+}
+
+int start_command(struct child_process *cmd)
+{
+ int need_in, need_out, need_err;
+ int fdin[2], fdout[2], fderr[2];
+ char sbuf[STRERR_BUFSIZE];
+
+ /*
+ * In case of errors we must keep the promise to close FDs
+ * that have been passed in via ->in and ->out.
+ */
+
+ need_in = !cmd->no_stdin && cmd->in < 0;
+ if (need_in) {
+ if (pipe(fdin) < 0) {
+ if (cmd->out > 0)
+ close(cmd->out);
+ return -ERR_RUN_COMMAND_PIPE;
+ }
+ cmd->in = fdin[1];
+ }
+
+ need_out = !cmd->no_stdout
+ && !cmd->stdout_to_stderr
+ && cmd->out < 0;
+ if (need_out) {
+ if (pipe(fdout) < 0) {
+ if (need_in)
+ close_pair(fdin);
+ else if (cmd->in)
+ close(cmd->in);
+ return -ERR_RUN_COMMAND_PIPE;
+ }
+ cmd->out = fdout[0];
+ }
+
+ need_err = !cmd->no_stderr && cmd->err < 0;
+ if (need_err) {
+ if (pipe(fderr) < 0) {
+ if (need_in)
+ close_pair(fdin);
+ else if (cmd->in)
+ close(cmd->in);
+ if (need_out)
+ close_pair(fdout);
+ else if (cmd->out)
+ close(cmd->out);
+ return -ERR_RUN_COMMAND_PIPE;
+ }
+ cmd->err = fderr[0];
+ }
+
+ fflush(NULL);
+ cmd->pid = fork();
+ if (!cmd->pid) {
+ if (cmd->no_stdin)
+ dup_devnull(0);
+ else if (need_in) {
+ dup2(fdin[0], 0);
+ close_pair(fdin);
+ } else if (cmd->in) {
+ dup2(cmd->in, 0);
+ close(cmd->in);
+ }
+
+ if (cmd->no_stderr)
+ dup_devnull(2);
+ else if (need_err) {
+ dup2(fderr[1], 2);
+ close_pair(fderr);
+ }
+
+ if (cmd->no_stdout)
+ dup_devnull(1);
+ else if (cmd->stdout_to_stderr)
+ dup2(2, 1);
+ else if (need_out) {
+ dup2(fdout[1], 1);
+ close_pair(fdout);
+ } else if (cmd->out > 1) {
+ dup2(cmd->out, 1);
+ close(cmd->out);
+ }
+
+ if (cmd->dir && chdir(cmd->dir))
+ die("exec %s: cd to %s failed (%s)", cmd->argv[0],
+ cmd->dir, str_error_r(errno, sbuf, sizeof(sbuf)));
+ if (cmd->env) {
+ for (; *cmd->env; cmd->env++) {
+ if (strchr(*cmd->env, '='))
+ putenv((char*)*cmd->env);
+ else
+ unsetenv(*cmd->env);
+ }
+ }
+ if (cmd->preexec_cb)
+ cmd->preexec_cb();
+ if (cmd->exec_cmd) {
+ execv_cmd(cmd->argv);
+ } else {
+ execvp(cmd->argv[0], (char *const*) cmd->argv);
+ }
+ exit(127);
+ }
+
+ if (cmd->pid < 0) {
+ int err = errno;
+ if (need_in)
+ close_pair(fdin);
+ else if (cmd->in)
+ close(cmd->in);
+ if (need_out)
+ close_pair(fdout);
+ else if (cmd->out)
+ close(cmd->out);
+ if (need_err)
+ close_pair(fderr);
+ return err == ENOENT ?
+ -ERR_RUN_COMMAND_EXEC :
+ -ERR_RUN_COMMAND_FORK;
+ }
+
+ if (need_in)
+ close(fdin[0]);
+ else if (cmd->in)
+ close(cmd->in);
+
+ if (need_out)
+ close(fdout[1]);
+ else if (cmd->out)
+ close(cmd->out);
+
+ if (need_err)
+ close(fderr[1]);
+
+ return 0;
+}
+
+static int wait_or_whine(pid_t pid)
+{
+ char sbuf[STRERR_BUFSIZE];
+
+ for (;;) {
+ int status, code;
+ pid_t waiting = waitpid(pid, &status, 0);
+
+ if (waiting < 0) {
+ if (errno == EINTR)
+ continue;
+ fprintf(stderr, " Error: waitpid failed (%s)",
+ str_error_r(errno, sbuf, sizeof(sbuf)));
+ return -ERR_RUN_COMMAND_WAITPID;
+ }
+ if (waiting != pid)
+ return -ERR_RUN_COMMAND_WAITPID_WRONG_PID;
+ if (WIFSIGNALED(status))
+ return -ERR_RUN_COMMAND_WAITPID_SIGNAL;
+
+ if (!WIFEXITED(status))
+ return -ERR_RUN_COMMAND_WAITPID_NOEXIT;
+ code = WEXITSTATUS(status);
+ switch (code) {
+ case 127:
+ return -ERR_RUN_COMMAND_EXEC;
+ case 0:
+ return 0;
+ default:
+ return -code;
+ }
+ }
+}
+
+int finish_command(struct child_process *cmd)
+{
+ return wait_or_whine(cmd->pid);
+}
+
+int run_command(struct child_process *cmd)
+{
+ int code = start_command(cmd);
+ if (code)
+ return code;
+ return finish_command(cmd);
+}
+
+static void prepare_run_command_v_opt(struct child_process *cmd,
+ const char **argv,
+ int opt)
+{
+ memset(cmd, 0, sizeof(*cmd));
+ cmd->argv = argv;
+ cmd->no_stdin = opt & RUN_COMMAND_NO_STDIN ? 1 : 0;
+ cmd->exec_cmd = opt & RUN_EXEC_CMD ? 1 : 0;
+ cmd->stdout_to_stderr = opt & RUN_COMMAND_STDOUT_TO_STDERR ? 1 : 0;
+}
+
+int run_command_v_opt(const char **argv, int opt)
+{
+ struct child_process cmd;
+ prepare_run_command_v_opt(&cmd, argv, opt);
+ return run_command(&cmd);
+}