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-rw-r--r--spawn.c318
1 files changed, 0 insertions, 318 deletions
diff --git a/spawn.c b/spawn.c
deleted file mode 100644
index 31f9897..0000000
--- a/spawn.c
+++ /dev/null
@@ -1,318 +0,0 @@
-/****************************************************************************
- * bfs *
- * Copyright (C) 2018-2022 Tavian Barnes <tavianator@tavianator.com> *
- * *
- * Permission to use, copy, modify, and/or distribute this software for any *
- * purpose with or without fee is hereby granted. *
- * *
- * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES *
- * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF *
- * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR *
- * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES *
- * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN *
- * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF *
- * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. *
- ****************************************************************************/
-
-#include "spawn.h"
-#include "util.h"
-#include <errno.h>
-#include <fcntl.h>
-#include <stdlib.h>
-#include <string.h>
-#include <sys/types.h>
-#include <sys/wait.h>
-#include <unistd.h>
-
-/**
- * Types of spawn actions.
- */
-enum bfs_spawn_op {
- BFS_SPAWN_CLOSE,
- BFS_SPAWN_DUP2,
- BFS_SPAWN_FCHDIR,
- BFS_SPAWN_SETRLIMIT,
-};
-
-/**
- * A spawn action.
- */
-struct bfs_spawn_action {
- struct bfs_spawn_action *next;
-
- enum bfs_spawn_op op;
- int in_fd;
- int out_fd;
- int resource;
- struct rlimit rlimit;
-};
-
-int bfs_spawn_init(struct bfs_spawn *ctx) {
- ctx->flags = 0;
- ctx->actions = NULL;
- ctx->tail = &ctx->actions;
- return 0;
-}
-
-int bfs_spawn_destroy(struct bfs_spawn *ctx) {
- struct bfs_spawn_action *action = ctx->actions;
- while (action) {
- struct bfs_spawn_action *next = action->next;
- free(action);
- action = next;
- }
- return 0;
-}
-
-int bfs_spawn_setflags(struct bfs_spawn *ctx, enum bfs_spawn_flags flags) {
- ctx->flags = flags;
- return 0;
-}
-
-/** Add a spawn action to the chain. */
-static struct bfs_spawn_action *bfs_spawn_add(struct bfs_spawn *ctx, enum bfs_spawn_op op) {
- struct bfs_spawn_action *action = malloc(sizeof(*action));
- if (action) {
- action->next = NULL;
- action->op = op;
- action->in_fd = -1;
- action->out_fd = -1;
-
- *ctx->tail = action;
- ctx->tail = &action->next;
- }
- return action;
-}
-
-int bfs_spawn_addclose(struct bfs_spawn *ctx, int fd) {
- if (fd < 0) {
- errno = EBADF;
- return -1;
- }
-
- struct bfs_spawn_action *action = bfs_spawn_add(ctx, BFS_SPAWN_CLOSE);
- if (action) {
- action->out_fd = fd;
- return 0;
- } else {
- return -1;
- }
-}
-
-int bfs_spawn_adddup2(struct bfs_spawn *ctx, int oldfd, int newfd) {
- if (oldfd < 0 || newfd < 0) {
- errno = EBADF;
- return -1;
- }
-
- struct bfs_spawn_action *action = bfs_spawn_add(ctx, BFS_SPAWN_DUP2);
- if (action) {
- action->in_fd = oldfd;
- action->out_fd = newfd;
- return 0;
- } else {
- return -1;
- }
-}
-
-int bfs_spawn_addfchdir(struct bfs_spawn *ctx, int fd) {
- if (fd < 0) {
- errno = EBADF;
- return -1;
- }
-
- struct bfs_spawn_action *action = bfs_spawn_add(ctx, BFS_SPAWN_FCHDIR);
- if (action) {
- action->in_fd = fd;
- return 0;
- } else {
- return -1;
- }
-}
-
-int bfs_spawn_addsetrlimit(struct bfs_spawn *ctx, int resource, const struct rlimit *rl) {
- struct bfs_spawn_action *action = bfs_spawn_add(ctx, BFS_SPAWN_SETRLIMIT);
- if (action) {
- action->resource = resource;
- action->rlimit = *rl;
- return 0;
- } else {
- return -1;
- }
-}
-
-/** Actually exec() the new process. */
-static void bfs_spawn_exec(const char *exe, const struct bfs_spawn *ctx, char **argv, char **envp, int pipefd[2]) {
- int error;
- const struct bfs_spawn_action *actions = ctx ? ctx->actions : NULL;
-
- xclose(pipefd[0]);
-
- for (const struct bfs_spawn_action *action = actions; action; action = action->next) {
- // Move the error-reporting pipe out of the way if necessary...
- if (action->out_fd == pipefd[1]) {
- int fd = dup_cloexec(pipefd[1]);
- if (fd < 0) {
- goto fail;
- }
- xclose(pipefd[1]);
- pipefd[1] = fd;
- }
-
- // ... and pretend the pipe doesn't exist
- if (action->in_fd == pipefd[1]) {
- errno = EBADF;
- goto fail;
- }
-
- switch (action->op) {
- case BFS_SPAWN_CLOSE:
- if (close(action->out_fd) != 0) {
- goto fail;
- }
- break;
- case BFS_SPAWN_DUP2:
- if (dup2(action->in_fd, action->out_fd) < 0) {
- goto fail;
- }
- break;
- case BFS_SPAWN_FCHDIR:
- if (fchdir(action->in_fd) != 0) {
- goto fail;
- }
- break;
- case BFS_SPAWN_SETRLIMIT:
- if (setrlimit(action->resource, &action->rlimit) != 0) {
- goto fail;
- }
- break;
- }
- }
-
- execve(exe, argv, envp);
-
-fail:
- error = errno;
-
- // In case of a write error, the parent will still see that we exited
- // unsuccessfully, but won't know why
- (void) xwrite(pipefd[1], &error, sizeof(error));
-
- xclose(pipefd[1]);
- _Exit(127);
-}
-
-pid_t bfs_spawn(const char *exe, const struct bfs_spawn *ctx, char **argv, char **envp) {
- extern char **environ;
- if (!envp) {
- envp = environ;
- }
-
- enum bfs_spawn_flags flags = ctx ? ctx->flags : 0;
- char *resolved = NULL;
- if (flags & BFS_SPAWN_USEPATH) {
- exe = resolved = bfs_spawn_resolve(exe);
- if (!resolved) {
- return -1;
- }
- }
-
- // Use a pipe to report errors from the child
- int pipefd[2];
- if (pipe_cloexec(pipefd) != 0) {
- free(resolved);
- return -1;
- }
-
- pid_t pid = fork();
- if (pid < 0) {
- close_quietly(pipefd[1]);
- close_quietly(pipefd[0]);
- free(resolved);
- return -1;
- } else if (pid == 0) {
- // Child
- bfs_spawn_exec(exe, ctx, argv, envp, pipefd);
- }
-
- // Parent
- xclose(pipefd[1]);
- free(resolved);
-
- int error;
- ssize_t nbytes = xread(pipefd[0], &error, sizeof(error));
- xclose(pipefd[0]);
- if (nbytes == sizeof(error)) {
- int wstatus;
- waitpid(pid, &wstatus, 0);
- errno = error;
- return -1;
- }
-
- return pid;
-}
-
-char *bfs_spawn_resolve(const char *exe) {
- if (strchr(exe, '/')) {
- return strdup(exe);
- }
-
- const char *path = getenv("PATH");
-
- char *confpath = NULL;
- if (!path) {
- path = confpath = xconfstr(_CS_PATH);
- if (!path) {
- return NULL;
- }
- }
-
- size_t cap = 0;
- char *ret = NULL;
- while (true) {
- const char *end = strchr(path, ':');
- size_t len = end ? (size_t)(end - path) : strlen(path);
-
- // POSIX 8.3: "A zero-length prefix is a legacy feature that
- // indicates the current working directory."
- if (len == 0) {
- path = ".";
- len = 1;
- }
-
- size_t total = len + 1 + strlen(exe) + 1;
- if (cap < total) {
- char *grown = realloc(ret, total);
- if (!grown) {
- goto fail;
- }
- ret = grown;
- cap = total;
- }
-
- memcpy(ret, path, len);
- if (ret[len - 1] != '/') {
- ret[len++] = '/';
- }
- strcpy(ret + len, exe);
-
- if (xfaccessat(AT_FDCWD, ret, X_OK) == 0) {
- break;
- }
-
- if (!end) {
- errno = ENOENT;
- goto fail;
- }
-
- path = end + 1;
- }
-
- free(confpath);
- return ret;
-
-fail:
- free(confpath);
- free(ret);
- return NULL;
-}
generated by cgit v1.2.3 (git 2.39.1) at 2024-05-06 23:30:17 +0000