summaryrefslogtreecommitdiffstats
path: root/src
diff options
context:
space:
mode:
authorTavian Barnes <tavianator@tavianator.com>2023-11-02 11:54:03 -0400
committerTavian Barnes <tavianator@tavianator.com>2023-11-06 10:16:08 -0500
commit95fbde17a66377b6fbe7ff1f014301dbbf09270d (patch)
tree5a98afd0242afc959a0317c52ab842d8e45030ad /src
parentad1b36291fe87ca9d647980e3afdc71344d66519 (diff)
downloadbfs-95fbde17a66377b6fbe7ff1f014301dbbf09270d.tar.xz
xspawn: Wrap the real posix_spawn() if possible
Fixes #47.
Diffstat (limited to 'src')
-rw-r--r--src/exec.c2
-rw-r--r--src/xspawn.c167
-rw-r--r--src/xspawn.h15
3 files changed, 136 insertions, 48 deletions
diff --git a/src/exec.c b/src/exec.c
index a3297e8..e3f7b97 100644
--- a/src/exec.c
+++ b/src/exec.c
@@ -363,7 +363,7 @@ static int bfs_exec_spawn(const struct bfs_exec *execbuf) {
return -1;
}
- if (bfs_spawn_setflags(&spawn, BFS_SPAWN_USEPATH) != 0) {
+ if (bfs_spawn_setflags(&spawn, BFS_SPAWN_USE_PATH) != 0) {
goto fail;
}
diff --git a/src/xspawn.c b/src/xspawn.c
index 64759e0..ac9e401 100644
--- a/src/xspawn.c
+++ b/src/xspawn.c
@@ -8,6 +8,7 @@
#include "list.h"
#include <errno.h>
#include <fcntl.h>
+#include <spawn.h>
#include <stdlib.h>
#include <string.h>
#include <sys/resource.h>
@@ -43,12 +44,27 @@ struct bfs_spawn_action {
};
int bfs_spawn_init(struct bfs_spawn *ctx) {
- ctx->flags = 0;
+ ctx->flags = BFS_SPAWN_USE_POSIX;
SLIST_INIT(ctx);
+
+ errno = posix_spawnattr_init(&ctx->attr);
+ if (errno != 0) {
+ return -1;
+ }
+
+ errno = posix_spawn_file_actions_init(&ctx->actions);
+ if (errno != 0) {
+ posix_spawnattr_destroy(&ctx->attr);
+ return -1;
+ }
+
return 0;
}
int bfs_spawn_destroy(struct bfs_spawn *ctx) {
+ posix_spawn_file_actions_destroy(&ctx->actions);
+ posix_spawnattr_destroy(&ctx->attr);
+
for_slist (struct bfs_spawn_action, action, ctx) {
free(action);
}
@@ -57,12 +73,12 @@ int bfs_spawn_destroy(struct bfs_spawn *ctx) {
}
int bfs_spawn_setflags(struct bfs_spawn *ctx, enum bfs_spawn_flags flags) {
- ctx->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) {
+/** Allocate a spawn action. */
+static struct bfs_spawn_action *bfs_spawn_action(enum bfs_spawn_op op) {
struct bfs_spawn_action *action = ALLOC(struct bfs_spawn_action);
if (!action) {
return NULL;
@@ -72,70 +88,122 @@ static struct bfs_spawn_action *bfs_spawn_add(struct bfs_spawn *ctx, enum bfs_sp
action->op = op;
action->in_fd = -1;
action->out_fd = -1;
-
- SLIST_APPEND(ctx, action);
return action;
}
int bfs_spawn_addclose(struct bfs_spawn *ctx, int fd) {
- if (fd < 0) {
- errno = EBADF;
+ struct bfs_spawn_action *action = bfs_spawn_action(BFS_SPAWN_CLOSE);
+ if (!action) {
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;
+ if (ctx->flags & BFS_SPAWN_USE_POSIX) {
+ errno = posix_spawn_file_actions_addclose(&ctx->actions, fd);
+ if (errno != 0) {
+ free(action);
+ return -1;
+ }
}
+
+ action->out_fd = fd;
+ SLIST_APPEND(ctx, action);
+ return 0;
}
int bfs_spawn_adddup2(struct bfs_spawn *ctx, int oldfd, int newfd) {
- if (oldfd < 0 || newfd < 0) {
- errno = EBADF;
+ struct bfs_spawn_action *action = bfs_spawn_action(BFS_SPAWN_DUP2);
+ if (!action) {
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;
+ if (ctx->flags & BFS_SPAWN_USE_POSIX) {
+ errno = posix_spawn_file_actions_adddup2(&ctx->actions, oldfd, newfd);
+ if (errno != 0) {
+ free(action);
+ return -1;
+ }
}
+
+ action->in_fd = oldfd;
+ action->out_fd = newfd;
+ SLIST_APPEND(ctx, action);
+ return 0;
}
int bfs_spawn_addfchdir(struct bfs_spawn *ctx, int fd) {
- if (fd < 0) {
- errno = EBADF;
+ struct bfs_spawn_action *action = bfs_spawn_action(BFS_SPAWN_FCHDIR);
+ if (!action) {
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;
+#ifndef BFS_HAS_POSIX_SPAWN_FCHDIR
+# define BFS_HAS_POSIX_SPAWN_FCHDIR __NetBSD__
+#endif
+
+#ifndef BFS_HAS_POSIX_SPAWN_FCHDIR_NP
+# if __GLIBC__
+# define BFS_HAS_POSIX_SPAWN_FCHDIR_NP __GLIBC_PREREQ(2, 29)
+# elif __ANDROID__
+# define BFS_HAS_POSIX_SPAWN_FCHDIR_NP (__ANDROID_API__ >= 34)
+# else
+# define BFS_HAS_POSIX_SPAWN_FCHDIR_NP (__linux__ || __FreeBSD__ || __APPLE__)
+# endif
+#endif
+
+#if BFS_HAS_POSIX_SPAWN_FCHDIR || BFS_HAS_POSIX_SPAWN_FCHDIR_NP
+ if (ctx->flags & BFS_SPAWN_USE_POSIX) {
+# if BFS_HAS_POSIX_SPAWN_FCHDIR
+ errno = posix_spawn_file_actions_addfchdir(&ctx->actions, fd);
+# else
+ errno = posix_spawn_file_actions_addfchdir_np(&ctx->actions, fd);
+# endif
+ if (errno != 0) {
+ free(action);
+ return -1;
+ }
}
+#else
+ ctx->flags &= ~BFS_SPAWN_USE_POSIX;
+#endif
+
+ action->in_fd = fd;
+ SLIST_APPEND(ctx, action);
+ return 0;
}
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 {
+ struct bfs_spawn_action *action = bfs_spawn_action(BFS_SPAWN_SETRLIMIT);
+ if (!action) {
return -1;
}
+
+ ctx->flags &= ~BFS_SPAWN_USE_POSIX;
+
+ action->resource = resource;
+ action->rlimit = *rl;
+ SLIST_APPEND(ctx, action);
+ return 0;
+}
+
+/** bfs_spawn() implementation using posix_spawn(). */
+static pid_t bfs_posix_spawn(const char *exe, const struct bfs_spawn *ctx, char **argv, char **envp) {
+ pid_t ret;
+
+ if (ctx->flags & BFS_SPAWN_USE_PATH) {
+ errno = posix_spawnp(&ret, exe, &ctx->actions, &ctx->attr, argv, envp);
+ } else {
+ errno = posix_spawn(&ret, exe, &ctx->actions, &ctx->attr, argv, envp);
+ }
+
+ if (errno != 0) {
+ ret = -1;
+ }
+
+ return ret;
}
/** 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]) {
+static noreturn void bfs_spawn_exec(const char *exe, const struct bfs_spawn *ctx, char **argv, char **envp, int pipefd[2]) {
xclose(pipefd[0]);
for_slist (const struct bfs_spawn_action, action, ctx) {
@@ -193,14 +261,10 @@ fail:
_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;
- }
-
+/** bfs_spawn() implementation using fork()/exec(). */
+static pid_t bfs_fork_spawn(const char *exe, const struct bfs_spawn *ctx, char **argv, char **envp) {
char *resolved = NULL;
- if (ctx->flags & BFS_SPAWN_USEPATH) {
+ if (ctx->flags & BFS_SPAWN_USE_PATH) {
exe = resolved = bfs_spawn_resolve(exe);
if (!resolved) {
return -1;
@@ -242,6 +306,19 @@ pid_t bfs_spawn(const char *exe, const struct bfs_spawn *ctx, char **argv, char
return pid;
}
+pid_t bfs_spawn(const char *exe, const struct bfs_spawn *ctx, char **argv, char **envp) {
+ extern char **environ;
+ if (!envp) {
+ envp = environ;
+ }
+
+ if (ctx->flags & BFS_SPAWN_USE_POSIX) {
+ return bfs_posix_spawn(exe, ctx, argv, envp);
+ } else {
+ return bfs_fork_spawn(exe, ctx, argv, envp);
+ }
+}
+
char *bfs_spawn_resolve(const char *exe) {
if (strchr(exe, '/')) {
return strdup(exe);
diff --git a/src/xspawn.h b/src/xspawn.h
index d9b4a2e..2a3d736 100644
--- a/src/xspawn.h
+++ b/src/xspawn.h
@@ -8,6 +8,8 @@
#ifndef BFS_XSPAWN_H
#define BFS_XSPAWN_H
+#include "config.h"
+#include <spawn.h>
#include <sys/resource.h>
#include <sys/types.h>
@@ -16,16 +18,25 @@
*/
enum bfs_spawn_flags {
/** Use the PATH variable to resolve the executable (like execvp()). */
- BFS_SPAWN_USEPATH = 1 << 0,
+ BFS_SPAWN_USE_PATH = 1 << 0,
+ /** Whether posix_spawn() can be used. */
+ BFS_SPAWN_USE_POSIX = 1 << 1,
};
/**
* bfs_spawn() attributes, controlling the context of the new process.
*/
struct bfs_spawn {
+ /** Spawn flags. */
enum bfs_spawn_flags flags;
+
+ /** Linked list of actions. */
struct bfs_spawn_action *head;
struct bfs_spawn_action **tail;
+
+ /** pthread_spawn() context, for when we can use it. */
+ posix_spawnattr_t attr;
+ posix_spawn_file_actions_t actions;
};
/**
@@ -95,7 +106,7 @@ int bfs_spawn_addsetrlimit(struct bfs_spawn *ctx, int resource, const struct rli
pid_t bfs_spawn(const char *exe, const struct bfs_spawn *ctx, char **argv, char **envp);
/**
- * Look up an executable in the current PATH, as BFS_SPAWN_USEPATH or execvp()
+ * Look up an executable in the current PATH, as BFS_SPAWN_USE_PATH or execvp()
* would do.
*
* @param exe