diff options
Diffstat (limited to 'exec.c')
| -rw-r--r-- | exec.c | 95 |
1 files changed, 77 insertions, 18 deletions
@@ -336,11 +336,30 @@ static int bfs_exec_spawn(const struct bfs_exec *execbuf) { bfs_exec_debug(execbuf, "Executing '%s' ... [%zu arguments]\n", execbuf->argv[0], execbuf->argc - 1); } + // Use a pipe to report errors from the child + int pipefd[2] = { -1, -1 }; + if (pipe_cloexec(pipefd) != 0) { + bfs_exec_debug(execbuf, "pipe() failed: %s\n", strerror(errno)); + } + pid_t pid = fork(); if (pid < 0) { + close(pipefd[1]); + close(pipefd[0]); return -1; } else if (pid > 0) { + // Parent + close(pipefd[1]); + + int error; + ssize_t nbytes = read(pipefd[0], &error, sizeof(error)); + close(pipefd[0]); + if (nbytes == sizeof(error)) { + errno = error; + return -1; + } + int status; if (waitpid(pid, &status, 0) < 0) { return -1; @@ -353,19 +372,22 @@ static int bfs_exec_spawn(const struct bfs_exec *execbuf) { return -1; } } else { + // Child + close(pipefd[0]); + if (execbuf->wd_fd >= 0) { if (fchdir(execbuf->wd_fd) != 0) { - perror("fchdir()"); - goto fail; + goto child_err; } } execvp(execbuf->argv[0], execbuf->argv); - perror("execvp()"); + child_err: + write(pipefd[1], &errno, sizeof(errno)); + close(pipefd[1]); + _Exit(EXIT_FAILURE); } -fail: - _Exit(EXIT_FAILURE); } /** exec() a command for a single file. */ @@ -412,33 +434,62 @@ out: return ret; } +/** Check if any arguments remain in the buffer. */ +static bool bfs_exec_args_remain(const struct bfs_exec *execbuf) { + return execbuf->argc >= execbuf->tmpl_argc; +} + /** Execute the pending command from a BFS_EXEC_MULTI execbuf. */ static int bfs_exec_flush(struct bfs_exec *execbuf) { int ret = 0; - if (execbuf->argc > execbuf->tmpl_argc - 1) { + size_t orig_argc = execbuf->argc; + while (bfs_exec_args_remain(execbuf)) { execbuf->argv[execbuf->argc] = NULL; - if (bfs_exec_spawn(execbuf) != 0) { - ret = -1; + ret = bfs_exec_spawn(execbuf); + if (ret == 0 || errno != E2BIG) { + break; } + + // Try to recover from E2BIG by trying fewer and fewer arguments + // until they fit + bfs_exec_debug(execbuf, "Got E2BIG, shrinking argument list...\n"); + execbuf->argv[execbuf->argc] = execbuf->argv[execbuf->argc - 1]; + execbuf->arg_size -= bfs_exec_arg_size(execbuf->argv[execbuf->argc]); + --execbuf->argc; } + size_t new_argc = execbuf->argc; int error = errno; - bfs_exec_closewd(execbuf, NULL); - - for (size_t i = execbuf->tmpl_argc - 1; i < execbuf->argc; ++i) { + for (size_t i = execbuf->tmpl_argc - 1; i < new_argc; ++i) { free(execbuf->argv[i]); } execbuf->argc = execbuf->tmpl_argc - 1; + + if (new_argc < orig_argc) { + // If we recovered from E2BIG, there are unused arguments at the + // end of the list + for (size_t i = new_argc + 1; i <= orig_argc; ++i) { + if (error == 0) { + execbuf->argv[execbuf->argc] = execbuf->argv[i]; + ++execbuf->argc; + } else { + free(execbuf->argv[i]); + } + } + + execbuf->arg_max = execbuf->arg_size; + bfs_exec_debug(execbuf, "ARG_MAX: %zu\n", execbuf->arg_max); + } execbuf->arg_size = 0; errno = error; return ret; } -/** Check if a flush is needed before a new file is processed. */ -static bool bfs_exec_needs_flush(struct bfs_exec *execbuf, const struct BFTW *ftwbuf, const char *arg) { +/** Check if we need to flush the execbuf because we're changing directories. */ +static bool bfs_exec_changed_dirs(const struct bfs_exec *execbuf, const struct BFTW *ftwbuf) { if (execbuf->flags & BFS_EXEC_CHDIR) { if (ftwbuf->nameoff > execbuf->wd_len || (execbuf->wd_path && strncmp(ftwbuf->path, execbuf->wd_path, execbuf->wd_len) != 0)) { @@ -447,6 +498,11 @@ static bool bfs_exec_needs_flush(struct bfs_exec *execbuf, const struct BFTW *ft } } + return false; +} + +/** Check if we need to flush the execbuf because we're too big. */ +static bool bfs_exec_would_overflow(const struct bfs_exec *execbuf, const char *arg) { size_t next_size = execbuf->arg_size + bfs_exec_arg_size(arg); if (next_size > execbuf->arg_max) { bfs_exec_debug(execbuf, "Command size (%zu) would exceed maximum (%zu), executing buffered command\n", @@ -486,10 +542,13 @@ static int bfs_exec_multi(struct bfs_exec *execbuf, const struct BFTW *ftwbuf) { goto out; } - if (bfs_exec_needs_flush(execbuf, ftwbuf, arg)) { - if (bfs_exec_flush(execbuf) != 0) { - ret = -1; + if (bfs_exec_changed_dirs(execbuf, ftwbuf)) { + while (bfs_exec_args_remain(execbuf)) { + ret |= bfs_exec_flush(execbuf); } + bfs_exec_closewd(execbuf, ftwbuf); + } else if (bfs_exec_would_overflow(execbuf, arg)) { + ret |= bfs_exec_flush(execbuf); } if ((execbuf->flags & BFS_EXEC_CHDIR) && execbuf->wd_fd < 0) { @@ -530,8 +589,8 @@ int bfs_exec(struct bfs_exec *execbuf, const struct BFTW *ftwbuf) { int bfs_exec_finish(struct bfs_exec *execbuf) { if (execbuf->flags & BFS_EXEC_MULTI) { bfs_exec_debug(execbuf, "Finishing execution, executing buffered command\n"); - if (bfs_exec_flush(execbuf) != 0) { - execbuf->ret = -1; + while (bfs_exec_args_remain(execbuf)) { + execbuf->ret |= bfs_exec_flush(execbuf); } } return execbuf->ret; |