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![bert Dvornik](/assets/img/avatar_default.png)
Fix the problem where the cmd->err passed into start_command wasn't being properly closed when certain types of errors occurr. (Compare the affected code with the clean shutdown code later in the function.) On Windows, this problem would be triggered if mingw_spawnvpe() failed, which would happen if the command to be executed was malformed (e.g. a text file that didn't start with a #! line). If cmd->err was a pipe, the failure to close it could result in a hang while the other side was waiting (forever) for either input or pipe close, e.g. while trying to shove the output into the side band. On msysGit, this problem was causing a hang in t5516-fetch-push. [J6t: With a slight adjustment of the test case, the hang is also observed on Linux.] Signed-off-by: bert Dvornik <dvornik+git@gmail.com> Signed-off-by: Johannes Sixt <j6t@kdbg.org> Signed-off-by: Junio C Hamano <gitster@pobox.com>
603 lines
13 KiB
C
603 lines
13 KiB
C
#include "cache.h"
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#include "run-command.h"
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#include "exec_cmd.h"
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static inline void close_pair(int fd[2])
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{
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close(fd[0]);
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close(fd[1]);
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}
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#ifndef WIN32
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static inline void dup_devnull(int to)
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{
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int fd = open("/dev/null", O_RDWR);
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dup2(fd, to);
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close(fd);
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}
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#endif
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static const char **prepare_shell_cmd(const char **argv)
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{
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int argc, nargc = 0;
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const char **nargv;
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for (argc = 0; argv[argc]; argc++)
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; /* just counting */
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/* +1 for NULL, +3 for "sh -c" plus extra $0 */
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nargv = xmalloc(sizeof(*nargv) * (argc + 1 + 3));
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if (argc < 1)
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die("BUG: shell command is empty");
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if (strcspn(argv[0], "|&;<>()$`\\\"' \t\n*?[#~=%") != strlen(argv[0])) {
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nargv[nargc++] = "sh";
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nargv[nargc++] = "-c";
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if (argc < 2)
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nargv[nargc++] = argv[0];
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else {
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struct strbuf arg0 = STRBUF_INIT;
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strbuf_addf(&arg0, "%s \"$@\"", argv[0]);
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nargv[nargc++] = strbuf_detach(&arg0, NULL);
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}
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}
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for (argc = 0; argv[argc]; argc++)
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nargv[nargc++] = argv[argc];
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nargv[nargc] = NULL;
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return nargv;
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}
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#ifndef WIN32
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static int execv_shell_cmd(const char **argv)
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{
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const char **nargv = prepare_shell_cmd(argv);
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trace_argv_printf(nargv, "trace: exec:");
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execvp(nargv[0], (char **)nargv);
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free(nargv);
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return -1;
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}
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#endif
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#ifndef WIN32
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static int child_err = 2;
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static int child_notifier = -1;
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static void notify_parent(void)
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{
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ssize_t unused;
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unused = write(child_notifier, "", 1);
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}
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static NORETURN void die_child(const char *err, va_list params)
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{
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char msg[4096];
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ssize_t unused;
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int len = vsnprintf(msg, sizeof(msg), err, params);
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if (len > sizeof(msg))
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len = sizeof(msg);
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unused = write(child_err, "fatal: ", 7);
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unused = write(child_err, msg, len);
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unused = write(child_err, "\n", 1);
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exit(128);
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}
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static inline void set_cloexec(int fd)
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{
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int flags = fcntl(fd, F_GETFD);
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if (flags >= 0)
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fcntl(fd, F_SETFD, flags | FD_CLOEXEC);
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}
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#endif
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static int wait_or_whine(pid_t pid, const char *argv0, int silent_exec_failure)
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{
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int status, code = -1;
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pid_t waiting;
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int failed_errno = 0;
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while ((waiting = waitpid(pid, &status, 0)) < 0 && errno == EINTR)
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; /* nothing */
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if (waiting < 0) {
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failed_errno = errno;
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error("waitpid for %s failed: %s", argv0, strerror(errno));
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} else if (waiting != pid) {
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error("waitpid is confused (%s)", argv0);
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} else if (WIFSIGNALED(status)) {
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code = WTERMSIG(status);
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error("%s died of signal %d", argv0, code);
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/*
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* This return value is chosen so that code & 0xff
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* mimics the exit code that a POSIX shell would report for
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* a program that died from this signal.
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*/
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code -= 128;
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} else if (WIFEXITED(status)) {
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code = WEXITSTATUS(status);
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/*
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* Convert special exit code when execvp failed.
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*/
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if (code == 127) {
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code = -1;
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failed_errno = ENOENT;
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if (!silent_exec_failure)
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error("cannot run %s: %s", argv0,
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strerror(ENOENT));
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}
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} else {
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error("waitpid is confused (%s)", argv0);
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}
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errno = failed_errno;
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return code;
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}
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int start_command(struct child_process *cmd)
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{
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int need_in, need_out, need_err;
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int fdin[2], fdout[2], fderr[2];
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int failed_errno = failed_errno;
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/*
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* In case of errors we must keep the promise to close FDs
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* that have been passed in via ->in and ->out.
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*/
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need_in = !cmd->no_stdin && cmd->in < 0;
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if (need_in) {
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if (pipe(fdin) < 0) {
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failed_errno = errno;
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if (cmd->out > 0)
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close(cmd->out);
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goto fail_pipe;
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}
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cmd->in = fdin[1];
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}
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need_out = !cmd->no_stdout
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&& !cmd->stdout_to_stderr
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&& cmd->out < 0;
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if (need_out) {
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if (pipe(fdout) < 0) {
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failed_errno = errno;
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if (need_in)
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close_pair(fdin);
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else if (cmd->in)
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close(cmd->in);
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goto fail_pipe;
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}
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cmd->out = fdout[0];
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}
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need_err = !cmd->no_stderr && cmd->err < 0;
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if (need_err) {
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if (pipe(fderr) < 0) {
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failed_errno = errno;
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if (need_in)
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close_pair(fdin);
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else if (cmd->in)
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close(cmd->in);
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if (need_out)
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close_pair(fdout);
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else if (cmd->out)
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close(cmd->out);
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fail_pipe:
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error("cannot create pipe for %s: %s",
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cmd->argv[0], strerror(failed_errno));
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errno = failed_errno;
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return -1;
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}
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cmd->err = fderr[0];
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}
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trace_argv_printf(cmd->argv, "trace: run_command:");
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#ifndef WIN32
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{
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int notify_pipe[2];
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if (pipe(notify_pipe))
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notify_pipe[0] = notify_pipe[1] = -1;
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fflush(NULL);
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cmd->pid = fork();
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if (!cmd->pid) {
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/*
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* Redirect the channel to write syscall error messages to
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* before redirecting the process's stderr so that all die()
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* in subsequent call paths use the parent's stderr.
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*/
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if (cmd->no_stderr || need_err) {
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child_err = dup(2);
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set_cloexec(child_err);
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}
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set_die_routine(die_child);
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close(notify_pipe[0]);
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set_cloexec(notify_pipe[1]);
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child_notifier = notify_pipe[1];
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atexit(notify_parent);
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if (cmd->no_stdin)
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dup_devnull(0);
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else if (need_in) {
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dup2(fdin[0], 0);
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close_pair(fdin);
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} else if (cmd->in) {
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dup2(cmd->in, 0);
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close(cmd->in);
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}
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if (cmd->no_stderr)
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dup_devnull(2);
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else if (need_err) {
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dup2(fderr[1], 2);
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close_pair(fderr);
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} else if (cmd->err > 1) {
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dup2(cmd->err, 2);
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close(cmd->err);
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}
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if (cmd->no_stdout)
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dup_devnull(1);
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else if (cmd->stdout_to_stderr)
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dup2(2, 1);
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else if (need_out) {
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dup2(fdout[1], 1);
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close_pair(fdout);
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} else if (cmd->out > 1) {
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dup2(cmd->out, 1);
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close(cmd->out);
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}
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if (cmd->dir && chdir(cmd->dir))
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die_errno("exec '%s': cd to '%s' failed", cmd->argv[0],
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cmd->dir);
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if (cmd->env) {
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for (; *cmd->env; cmd->env++) {
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if (strchr(*cmd->env, '='))
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putenv((char *)*cmd->env);
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else
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unsetenv(*cmd->env);
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}
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}
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if (cmd->preexec_cb) {
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/*
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* We cannot predict what the pre-exec callback does.
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* Forgo parent notification.
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*/
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close(child_notifier);
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child_notifier = -1;
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cmd->preexec_cb();
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}
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if (cmd->git_cmd) {
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execv_git_cmd(cmd->argv);
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} else if (cmd->use_shell) {
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execv_shell_cmd(cmd->argv);
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} else {
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execvp(cmd->argv[0], (char *const*) cmd->argv);
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}
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/*
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* Do not check for cmd->silent_exec_failure; the parent
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* process will check it when it sees this exit code.
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*/
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if (errno == ENOENT)
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exit(127);
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else
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die_errno("cannot exec '%s'", cmd->argv[0]);
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}
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if (cmd->pid < 0)
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error("cannot fork() for %s: %s", cmd->argv[0],
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strerror(failed_errno = errno));
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/*
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* Wait for child's execvp. If the execvp succeeds (or if fork()
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* failed), EOF is seen immediately by the parent. Otherwise, the
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* child process sends a single byte.
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* Note that use of this infrastructure is completely advisory,
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* therefore, we keep error checks minimal.
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*/
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close(notify_pipe[1]);
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if (read(notify_pipe[0], ¬ify_pipe[1], 1) == 1) {
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/*
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* At this point we know that fork() succeeded, but execvp()
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* failed. Errors have been reported to our stderr.
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*/
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wait_or_whine(cmd->pid, cmd->argv[0],
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cmd->silent_exec_failure);
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failed_errno = errno;
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cmd->pid = -1;
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}
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close(notify_pipe[0]);
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}
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#else
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{
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int fhin = 0, fhout = 1, fherr = 2;
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const char **sargv = cmd->argv;
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char **env = environ;
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if (cmd->no_stdin)
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fhin = open("/dev/null", O_RDWR);
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else if (need_in)
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fhin = dup(fdin[0]);
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else if (cmd->in)
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fhin = dup(cmd->in);
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if (cmd->no_stderr)
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fherr = open("/dev/null", O_RDWR);
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else if (need_err)
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fherr = dup(fderr[1]);
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else if (cmd->err > 2)
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fherr = dup(cmd->err);
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if (cmd->no_stdout)
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fhout = open("/dev/null", O_RDWR);
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else if (cmd->stdout_to_stderr)
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fhout = dup(fherr);
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else if (need_out)
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fhout = dup(fdout[1]);
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else if (cmd->out > 1)
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fhout = dup(cmd->out);
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if (cmd->env)
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env = make_augmented_environ(cmd->env);
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if (cmd->git_cmd) {
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cmd->argv = prepare_git_cmd(cmd->argv);
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} else if (cmd->use_shell) {
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cmd->argv = prepare_shell_cmd(cmd->argv);
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}
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cmd->pid = mingw_spawnvpe(cmd->argv[0], cmd->argv, env, cmd->dir,
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fhin, fhout, fherr);
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failed_errno = errno;
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if (cmd->pid < 0 && (!cmd->silent_exec_failure || errno != ENOENT))
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error("cannot spawn %s: %s", cmd->argv[0], strerror(errno));
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if (cmd->env)
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free_environ(env);
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if (cmd->git_cmd)
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free(cmd->argv);
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cmd->argv = sargv;
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if (fhin != 0)
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close(fhin);
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if (fhout != 1)
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close(fhout);
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if (fherr != 2)
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close(fherr);
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}
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#endif
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if (cmd->pid < 0) {
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if (need_in)
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close_pair(fdin);
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else if (cmd->in)
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close(cmd->in);
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if (need_out)
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close_pair(fdout);
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else if (cmd->out)
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close(cmd->out);
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if (need_err)
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close_pair(fderr);
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else if (cmd->err)
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close(cmd->err);
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errno = failed_errno;
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return -1;
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}
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if (need_in)
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close(fdin[0]);
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else if (cmd->in)
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close(cmd->in);
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if (need_out)
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close(fdout[1]);
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else if (cmd->out)
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close(cmd->out);
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if (need_err)
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close(fderr[1]);
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else if (cmd->err)
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close(cmd->err);
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return 0;
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}
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int finish_command(struct child_process *cmd)
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{
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return wait_or_whine(cmd->pid, cmd->argv[0], cmd->silent_exec_failure);
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}
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int run_command(struct child_process *cmd)
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{
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int code = start_command(cmd);
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if (code)
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return code;
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return finish_command(cmd);
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}
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static void prepare_run_command_v_opt(struct child_process *cmd,
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const char **argv,
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int opt)
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{
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memset(cmd, 0, sizeof(*cmd));
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cmd->argv = argv;
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cmd->no_stdin = opt & RUN_COMMAND_NO_STDIN ? 1 : 0;
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cmd->git_cmd = opt & RUN_GIT_CMD ? 1 : 0;
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cmd->stdout_to_stderr = opt & RUN_COMMAND_STDOUT_TO_STDERR ? 1 : 0;
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cmd->silent_exec_failure = opt & RUN_SILENT_EXEC_FAILURE ? 1 : 0;
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cmd->use_shell = opt & RUN_USING_SHELL ? 1 : 0;
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}
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int run_command_v_opt(const char **argv, int opt)
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{
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struct child_process cmd;
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prepare_run_command_v_opt(&cmd, argv, opt);
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return run_command(&cmd);
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}
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int run_command_v_opt_cd_env(const char **argv, int opt, const char *dir, const char *const *env)
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{
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struct child_process cmd;
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prepare_run_command_v_opt(&cmd, argv, opt);
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cmd.dir = dir;
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cmd.env = env;
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return run_command(&cmd);
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}
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#ifdef WIN32
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static unsigned __stdcall run_thread(void *data)
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{
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struct async *async = data;
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return async->proc(async->proc_in, async->proc_out, async->data);
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}
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#endif
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int start_async(struct async *async)
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{
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int need_in, need_out;
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int fdin[2], fdout[2];
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int proc_in, proc_out;
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need_in = async->in < 0;
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if (need_in) {
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if (pipe(fdin) < 0) {
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if (async->out > 0)
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close(async->out);
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return error("cannot create pipe: %s", strerror(errno));
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}
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async->in = fdin[1];
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}
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need_out = async->out < 0;
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if (need_out) {
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if (pipe(fdout) < 0) {
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if (need_in)
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close_pair(fdin);
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else if (async->in)
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close(async->in);
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return error("cannot create pipe: %s", strerror(errno));
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}
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async->out = fdout[0];
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}
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if (need_in)
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proc_in = fdin[0];
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else if (async->in)
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proc_in = async->in;
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else
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proc_in = -1;
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if (need_out)
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proc_out = fdout[1];
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else if (async->out)
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proc_out = async->out;
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else
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proc_out = -1;
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#ifndef WIN32
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/* Flush stdio before fork() to avoid cloning buffers */
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fflush(NULL);
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async->pid = fork();
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if (async->pid < 0) {
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error("fork (async) failed: %s", strerror(errno));
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goto error;
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}
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if (!async->pid) {
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if (need_in)
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close(fdin[1]);
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if (need_out)
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close(fdout[0]);
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exit(!!async->proc(proc_in, proc_out, async->data));
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}
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if (need_in)
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close(fdin[0]);
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else if (async->in)
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close(async->in);
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if (need_out)
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close(fdout[1]);
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else if (async->out)
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close(async->out);
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#else
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async->proc_in = proc_in;
|
|
async->proc_out = proc_out;
|
|
async->tid = (HANDLE) _beginthreadex(NULL, 0, run_thread, async, 0, NULL);
|
|
if (!async->tid) {
|
|
error("cannot create thread: %s", strerror(errno));
|
|
goto error;
|
|
}
|
|
#endif
|
|
return 0;
|
|
|
|
error:
|
|
if (need_in)
|
|
close_pair(fdin);
|
|
else if (async->in)
|
|
close(async->in);
|
|
|
|
if (need_out)
|
|
close_pair(fdout);
|
|
else if (async->out)
|
|
close(async->out);
|
|
return -1;
|
|
}
|
|
|
|
int finish_async(struct async *async)
|
|
{
|
|
#ifndef WIN32
|
|
int ret = wait_or_whine(async->pid, "child process", 0);
|
|
#else
|
|
DWORD ret = 0;
|
|
if (WaitForSingleObject(async->tid, INFINITE) != WAIT_OBJECT_0)
|
|
ret = error("waiting for thread failed: %lu", GetLastError());
|
|
else if (!GetExitCodeThread(async->tid, &ret))
|
|
ret = error("cannot get thread exit code: %lu", GetLastError());
|
|
CloseHandle(async->tid);
|
|
#endif
|
|
return ret;
|
|
}
|
|
|
|
int run_hook(const char *index_file, const char *name, ...)
|
|
{
|
|
struct child_process hook;
|
|
const char **argv = NULL, *env[2];
|
|
char index[PATH_MAX];
|
|
va_list args;
|
|
int ret;
|
|
size_t i = 0, alloc = 0;
|
|
|
|
if (access(git_path("hooks/%s", name), X_OK) < 0)
|
|
return 0;
|
|
|
|
va_start(args, name);
|
|
ALLOC_GROW(argv, i + 1, alloc);
|
|
argv[i++] = git_path("hooks/%s", name);
|
|
while (argv[i-1]) {
|
|
ALLOC_GROW(argv, i + 1, alloc);
|
|
argv[i++] = va_arg(args, const char *);
|
|
}
|
|
va_end(args);
|
|
|
|
memset(&hook, 0, sizeof(hook));
|
|
hook.argv = argv;
|
|
hook.no_stdin = 1;
|
|
hook.stdout_to_stderr = 1;
|
|
if (index_file) {
|
|
snprintf(index, sizeof(index), "GIT_INDEX_FILE=%s", index_file);
|
|
env[0] = index;
|
|
env[1] = NULL;
|
|
hook.env = env;
|
|
}
|
|
|
|
ret = run_command(&hook);
|
|
free(argv);
|
|
return ret;
|
|
}
|