run-command: use the async-signal-safe execv instead of execvp

diff --git a/run-command.c b/run-command.c
index 574b81d3e82bbe6de31b141c3951ab408daad5e6..1c7a3b6110a472d2d437a07aa3ea7193d2158551 100644 (file)
--- a/run-command.c
+++ b/run-command.c
@@ -220,18 +220,6 @@ static const char **prepare_shell_cmd(struct argv_array *out, const char **argv)
        return out->argv;
 }
 
-#ifndef GIT_WINDOWS_NATIVE
-static int execv_shell_cmd(const char **argv)
-{
-       struct argv_array nargv = ARGV_ARRAY_INIT;
-       prepare_shell_cmd(&nargv, argv);
-       trace_argv_printf(nargv.argv, "trace: exec:");
-       sane_execvp(nargv.argv[0], (char **)nargv.argv);
-       argv_array_clear(&nargv);
-       return -1;
-}
-#endif
-
 #ifndef GIT_WINDOWS_NATIVE
 static int child_notifier = -1;
 
@@ -244,6 +232,41 @@ static void notify_parent(void)
         */
        xwrite(child_notifier, "", 1);
 }
+
+static void prepare_cmd(struct argv_array *out, const struct child_process *cmd)
+{
+       if (!cmd->argv[0])
+               die("BUG: command is empty");
+
+       /*
+        * Add SHELL_PATH so in the event exec fails with ENOEXEC we can
+        * attempt to interpret the command with 'sh'.
+        */
+       argv_array_push(out, SHELL_PATH);
+
+       if (cmd->git_cmd) {
+               argv_array_push(out, "git");
+               argv_array_pushv(out, cmd->argv);
+       } else if (cmd->use_shell) {
+               prepare_shell_cmd(out, cmd->argv);
+       } else {
+               argv_array_pushv(out, cmd->argv);
+       }
+
+       /*
+        * If there are no '/' characters in the command then perform a path
+        * lookup and use the resolved path as the command to exec.  If there
+        * are no '/' characters or if the command wasn't found in the path,
+        * have exec attempt to invoke the command directly.
+        */
+       if (!strchr(out->argv[1], '/')) {
+               char *program = locate_in_PATH(out->argv[1]);
+               if (program) {
+                       free((char *)out->argv[1]);
+                       out->argv[1] = program;
+               }
+       }
+}
 #endif
 
 static inline void set_cloexec(int fd)
@@ -372,9 +395,13 @@ int start_command(struct child_process *cmd)
 #ifndef GIT_WINDOWS_NATIVE
 {
        int notify_pipe[2];
+       struct argv_array argv = ARGV_ARRAY_INIT;
+
        if (pipe(notify_pipe))
                notify_pipe[0] = notify_pipe[1] = -1;
 
+       prepare_cmd(&argv, cmd);
+
        cmd->pid = fork();
        failed_errno = errno;
        if (!cmd->pid) {
@@ -437,12 +464,17 @@ int start_command(struct child_process *cmd)
                                        unsetenv(*cmd->env);
                        }
                }
-               if (cmd->git_cmd)
-                       execv_git_cmd(cmd->argv);
-               else if (cmd->use_shell)
-                       execv_shell_cmd(cmd->argv);
-               else
-                       sane_execvp(cmd->argv[0], (char *const*) cmd->argv);
+
+               /*
+                * Attempt to exec using the command and arguments starting at
+                * argv.argv[1].  argv.argv[0] contains SHELL_PATH which will
+                * be used in the event exec failed with ENOEXEC at which point
+                * we will try to interpret the command using 'sh'.
+                */
+               execv(argv.argv[1], (char *const *) argv.argv + 1);
+               if (errno == ENOEXEC)
+                       execv(argv.argv[0], (char *const *) argv.argv);
+
                if (errno == ENOENT) {
                        if (!cmd->silent_exec_failure)
                                error("cannot run %s: %s", cmd->argv[0],
@@ -458,7 +490,7 @@ int start_command(struct child_process *cmd)
                mark_child_for_cleanup(cmd->pid, cmd);
 
        /*
-        * Wait for child's execvp. If the execvp succeeds (or if fork()
+        * Wait for child's exec. If the exec succeeds (or if fork()
         * failed), EOF is seen immediately by the parent. Otherwise, the
         * child process sends a single byte.
         * Note that use of this infrastructure is completely advisory,
@@ -467,7 +499,7 @@ int start_command(struct child_process *cmd)
        close(notify_pipe[1]);
        if (read(notify_pipe[0], &notify_pipe[1], 1) == 1) {
                /*
-                * At this point we know that fork() succeeded, but execvp()
+                * At this point we know that fork() succeeded, but exec()
                 * failed. Errors have been reported to our stderr.
                 */
                wait_or_whine(cmd->pid, cmd->argv[0], 0);
@@ -475,6 +507,8 @@ int start_command(struct child_process *cmd)
                cmd->pid = -1;
        }
        close(notify_pipe[0]);
+
+       argv_array_clear(&argv);
 }
 #else
 {