MINOR: debug: replace popen() with pipe+fork() in "debug dev exec"

popen() is annoying because it doesn't catch stderr. The command was
implemented using it just by pure laziness, let's just redo it a bit
cleaner using normal syscalls. Note that this command is only enabled
when built with -DDEBUG_DEV.

diff --git a/src/debug.c b/src/debug.c
index fe2fe310c91639de099c6b09d321170847630d67..41fa7ae4a16f65bbed237bd5767f3db58bb264a6 100644 (file)
--- a/src/debug.c
+++ b/src/debug.c
@@ -10,10 +10,13 @@
  *
  */
 
+#include <fcntl.h>
 #include <signal.h>
 #include <time.h>
 #include <stdio.h>
 #include <stdlib.h>
+#include <sys/types.h>
+#include <sys/wait.h>
 
 #include <common/buf.h>
 #include <common/config.h>
@@ -310,8 +313,9 @@ static int debug_parse_cli_panic(char **args, char *payload, struct appctx *appc
 #if defined(DEBUG_DEV)
 static int debug_parse_cli_exec(char **args, char *payload, struct appctx *appctx, void *private)
 {
-       FILE *f;
+       int pipefd[2];
        int arg;
+       int pid;
 
        if (!cli_has_level(appctx, ACCESS_LVL_ADMIN))
                return 1;
@@ -324,14 +328,41 @@ static int debug_parse_cli_exec(char **args, char *payload, struct appctx *appct
                chunk_strcat(&trash, args[arg]);
        }
 
-       f = popen(trash.area, "re");
-       if (!f)
-               return cli_err(appctx, "Failed to execute command.\n");
+       thread_isolate();
+       if (pipe(pipefd) < 0)
+               goto fail_pipe;
 
+       if (fcntl(pipefd[0], F_SETFD, fcntl(pipefd[0], F_GETFD, FD_CLOEXEC) | FD_CLOEXEC) == -1)
+               goto fail_fcntl;
+
+       if (fcntl(pipefd[1], F_SETFD, fcntl(pipefd[1], F_GETFD, FD_CLOEXEC) | FD_CLOEXEC) == -1)
+               goto fail_fcntl;
+
+       pid = fork();
+
+       if (pid < 0)
+               goto fail_fork;
+       else if (pid == 0) {
+               /* child */
+               char *cmd[4] = { "/bin/sh", "-c", 0, 0 };
+
+               close(0);
+               dup2(pipefd[1], 1);
+               dup2(pipefd[1], 2);
+
+               cmd[2] = trash.area;
+               execvp(cmd[0], cmd);
+               printf("execvp() failed\n");
+               exit(1);
+       }
+
+       /* parent */
+       thread_release();
+       close(pipefd[1]);
        chunk_reset(&trash);
        while (1) {
-               size_t ret = fread(trash.area + trash.data, 1, trash.size - 20 - trash.data, f);
-               if (!ret)
+               size_t ret = read(pipefd[0], trash.area + trash.data, trash.size - 20 - trash.data);
+               if (ret <= 0)
                        break;
                trash.data += ret;
                if (trash.data + 20 == trash.size) {
@@ -339,10 +370,18 @@ static int debug_parse_cli_exec(char **args, char *payload, struct appctx *appct
                        break;
                }
        }
-
-       fclose(f);
+       close(pipefd[0]);
+       waitpid(pid, NULL, WNOHANG);
        trash.area[trash.data] = 0;
        return cli_msg(appctx, LOG_INFO, trash.area);
+
+ fail_fork:
+ fail_fcntl:
+       close(pipefd[0]);
+       close(pipefd[1]);
+ fail_pipe:
+       thread_release();
+       return cli_err(appctx, "Failed to execute command.\n");
 }
 #endif