pipecmd: fix warn-unused-result warnings (-O2)

[ccan] / ccan / pipecmd / pipecmd.c

diff --git a/ccan/pipecmd/pipecmd.c b/ccan/pipecmd/pipecmd.c
index 352677fac1c216240eb38252216f72584793221c..22903bb34627b0df674f7c14b78dfe7a7907bb74 100644 (file)
--- a/ccan/pipecmd/pipecmd.c
+++ b/ccan/pipecmd/pipecmd.c
@@ -16,16 +16,35 @@ static char **gather_args(const char *arg0, va_list ap)
        arr[0] = (char *)arg0;
 
        while ((arr[n++] = va_arg(ap, char *)) != NULL) {
-               arr = realloc(arr, sizeof(char *) * (n + 1));
-               if (!arr)
+               char **narr = realloc(arr, sizeof(char *) * (n + 1));
+               if (!narr) {
+                       free(arr);
                        return NULL;
+               }
+               arr = narr;
        }
        return arr;
 }
 
-pid_t pipecmdv(int *fd_fromchild, int *fd_tochild, const char *cmd, va_list ap)
+pid_t pipecmdv(int *fd_fromchild, int *fd_tochild, int *fd_errfromchild,
+              const char *cmd, va_list ap)
+{
+       char **arr = gather_args(cmd, ap);
+       pid_t ret;
+
+       if (!arr) {
+               errno = ENOMEM;
+               return -1;
+       }
+       ret = pipecmdarr(fd_fromchild, fd_tochild, fd_errfromchild, arr);
+       free_noerr(arr);
+       return ret;
+}
+
+pid_t pipecmdarr(int *fd_fromchild, int *fd_tochild, int *fd_errfromchild,
+                char *const *arr)
 {
-       int tochild[2], fromchild[2], execfail[2];
+       int tochild[2], fromchild[2], errfromchild[2], execfail[2];
        pid_t childpid;
        int err;
 
@@ -45,8 +64,22 @@ pid_t pipecmdv(int *fd_fromchild, int *fd_tochild, const char *cmd, va_list ap)
                if (fromchild[1] < 0)
                        goto close_tochild_fail;
        }
+       if (fd_errfromchild) {
+               if (fd_errfromchild == fd_fromchild) {
+                       errfromchild[0] = fromchild[0];
+                       errfromchild[1] = fromchild[1];
+               } else {
+                       if (pipe(errfromchild) != 0)
+                               goto close_fromchild_fail;
+               }
+       } else {
+               errfromchild[1] = open("/dev/null", O_WRONLY);
+               if (errfromchild[1] < 0)
+                       goto close_fromchild_fail;
+       }
+               
        if (pipe(execfail) != 0)
-               goto close_fromchild_fail;
+               goto close_errfromchild_fail;
 
        if (fcntl(execfail[1], F_SETFD, fcntl(execfail[1], F_GETFD)
                  | FD_CLOEXEC) < 0)
@@ -57,54 +90,71 @@ pid_t pipecmdv(int *fd_fromchild, int *fd_tochild, const char *cmd, va_list ap)
                goto close_execfail_fail;
 
        if (childpid == 0) {
-               char **args = gather_args(cmd, ap);
-
                if (fd_tochild)
                        close(tochild[1]);
                if (fd_fromchild)
                        close(fromchild[0]);
+               if (fd_errfromchild && fd_errfromchild != fd_fromchild)
+                       close(errfromchild[0]);
+
                close(execfail[0]);
 
                // Child runs command.
-               if (!args)
-                       err = ENOMEM;
-               else {
-                       if (tochild[0] != STDIN_FILENO) {
-                               if (dup2(tochild[0], STDIN_FILENO) == -1)
-                                       goto child_errno_fail;
-                               close(tochild[0]);
-                       }
-                       if (fromchild[1] != STDOUT_FILENO) {
-                               if (dup2(fromchild[1], STDOUT_FILENO) == -1)
-                                       goto child_errno_fail;
-                               close(fromchild[1]);
-                       }
-                       execvp(cmd, args);
-               child_errno_fail:
-                       err = errno;
+               if (tochild[0] != STDIN_FILENO) {
+                       if (dup2(tochild[0], STDIN_FILENO) == -1)
+                               goto child_errno_fail;
+                       close(tochild[0]);
                }
-               write(execfail[1], &err, sizeof(err));
+               if (fromchild[1] != STDOUT_FILENO) {
+                       if (dup2(fromchild[1], STDOUT_FILENO) == -1)
+                               goto child_errno_fail;
+                       close(fromchild[1]);
+               }
+               if (fd_errfromchild && fd_errfromchild == fd_fromchild) {
+                       if (dup2(STDOUT_FILENO, STDERR_FILENO) == -1)
+                               goto child_errno_fail;
+               } else if (errfromchild[1] != STDERR_FILENO) {
+                       if (dup2(errfromchild[1], STDERR_FILENO) == -1)
+                               goto child_errno_fail;
+                       close(errfromchild[1]);
+               }
+               execvp(arr[0], arr);
+
+       child_errno_fail:
+               err = errno;
+               /* Gcc's warn-unused-result fail. */
+               if (write(execfail[1], &err, sizeof(err)))
+                       ;
                exit(127);
        }
 
        close(tochild[0]);
        close(fromchild[1]);
+       close(errfromchild[1]);
        close(execfail[1]);
        /* Child will close this without writing on successful exec. */
        if (read(execfail[0], &err, sizeof(err)) == sizeof(err)) {
+               close(execfail[0]);
                waitpid(childpid, NULL, 0);
                errno = err;
                return -1;
        }
+       close(execfail[0]);
        if (fd_tochild)
                *fd_tochild = tochild[1];
        if (fd_fromchild)
                *fd_fromchild = fromchild[0];
+       if (fd_errfromchild)
+               *fd_errfromchild = errfromchild[0];
        return childpid;
 
 close_execfail_fail:
        close_noerr(execfail[0]);
        close_noerr(execfail[1]);
+close_errfromchild_fail:
+       if (fd_errfromchild)
+               close_noerr(errfromchild[0]);
+       close_noerr(errfromchild[1]);
 close_fromchild_fail:
        if (fd_fromchild)
                close_noerr(fromchild[0]);
@@ -117,13 +167,14 @@ fail:
        return -1;
 }
 
-pid_t pipecmd(int *fd_fromchild, int *fd_tochild, const char *cmd, ...)
+pid_t pipecmd(int *fd_fromchild, int *fd_tochild, int *fd_errfromchild,
+             const char *cmd, ...)
 {
        pid_t childpid;
 
        va_list ap;
        va_start(ap, cmd);
-       childpid = pipecmdv(fd_fromchild, fd_tochild, cmd, ap);
+       childpid = pipecmdv(fd_fromchild, fd_tochild, fd_errfromchild, cmd, ap);
        va_end(ap);
 
        return childpid;