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authorRich Felker <dalias@aerifal.cx>2018-09-10 16:13:29 -0400
committerRich Felker <dalias@aerifal.cx>2018-09-12 14:34:32 -0400
commitfe61a7aa53e68e8a17b5eb8d502e6fa314139ced (patch)
tree76624120cdf978e0d5c3a995d27e09eeba1a1151
parent039f1b3c564667ab6fc9955bd892c2e527eb80b0 (diff)
downloadmusl-fe61a7aa53e68e8a17b5eb8d502e6fa314139ced.tar.gz
rework mechanism for posix_spawnp calling posix_spawn
previously, a common __posix_spawnx backend was used that accepted an additional argument for the execve variant to call in the child. this moderately bloated up the posix_spawn function, shuffling arguments between stack and/or registers to call a 7-argument function from a 6-argument one. instead, tuck the exec function pointer in an unused part of the (large) pthread_spawnattr_t structure, and have posix_spawnp duplicate the attributes and fill in a pointer to __execvpe. the net code size change is minimal, but the weight is shifted to the "heavier" function which already pulls in more dependencies. as a bonus, we get rid of an external symbol (__posix_spawnx) that had no really good place for a declaration because it shouldn't have existed to begin with.
-rw-r--r--include/spawn.h4
-rw-r--r--src/process/posix_spawn.c18
-rw-r--r--src/process/posix_spawnp.c10
3 files changed, 12 insertions, 20 deletions
diff --git a/include/spawn.h b/include/spawn.h
index bba57ce4..c9bd1939 100644
--- a/include/spawn.h
+++ b/include/spawn.h
@@ -28,7 +28,9 @@ typedef struct {
int __flags;
pid_t __pgrp;
sigset_t __def, __mask;
- int __prio, __pol, __pad[16];
+ int __prio, __pol;
+ void *__fn;
+ char __pad[64-sizeof(void *)];
} posix_spawnattr_t;
typedef struct {
diff --git a/src/process/posix_spawn.c b/src/process/posix_spawn.c
index 93fb1555..16308fb7 100644
--- a/src/process/posix_spawn.c
+++ b/src/process/posix_spawn.c
@@ -14,7 +14,6 @@ struct args {
int p[2];
sigset_t oldmask;
const char *path;
- int (*exec)(const char *, char *const *, char *const *);
const posix_spawn_file_actions_t *fa;
const posix_spawnattr_t *restrict attr;
char *const *argv, *const *envp;
@@ -138,7 +137,10 @@ static int child(void *args_vp)
pthread_sigmask(SIG_SETMASK, (attr->__flags & POSIX_SPAWN_SETSIGMASK)
? &attr->__mask : &args->oldmask, 0);
- args->exec(args->path, args->argv, args->envp);
+ int (*exec)(const char *, char *const *, char *const *) =
+ attr->__fn ? (int (*)())attr->__fn : execve;
+
+ exec(args->path, args->argv, args->envp);
ret = -errno;
fail:
@@ -149,8 +151,7 @@ fail:
}
-int __posix_spawnx(pid_t *restrict res, const char *restrict path,
- int (*exec)(const char *, char *const *, char *const *),
+int posix_spawn(pid_t *restrict res, const char *restrict path,
const posix_spawn_file_actions_t *fa,
const posix_spawnattr_t *restrict attr,
char *const argv[restrict], char *const envp[restrict])
@@ -166,7 +167,6 @@ int __posix_spawnx(pid_t *restrict res, const char *restrict path,
pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
args.path = path;
- args.exec = exec;
args.fa = fa;
args.attr = attr ? attr : &(const posix_spawnattr_t){0};
args.argv = argv;
@@ -193,11 +193,3 @@ int __posix_spawnx(pid_t *restrict res, const char *restrict path,
return ec;
}
-
-int posix_spawn(pid_t *restrict res, const char *restrict path,
- const posix_spawn_file_actions_t *fa,
- const posix_spawnattr_t *restrict attr,
- char *const argv[restrict], char *const envp[restrict])
-{
- return __posix_spawnx(res, path, execve, fa, attr, argv, envp);
-}
diff --git a/src/process/posix_spawnp.c b/src/process/posix_spawnp.c
index 37360001..165be746 100644
--- a/src/process/posix_spawnp.c
+++ b/src/process/posix_spawnp.c
@@ -3,15 +3,13 @@
int __execvpe(const char *, char *const *, char *const *);
-int __posix_spawnx(pid_t *restrict, const char *restrict,
- int (*)(const char *, char *const *, char *const *),
- const posix_spawn_file_actions_t *,
- const posix_spawnattr_t *restrict, char *const *restrict, char *const *restrict);
-
int posix_spawnp(pid_t *restrict res, const char *restrict file,
const posix_spawn_file_actions_t *fa,
const posix_spawnattr_t *restrict attr,
char *const argv[restrict], char *const envp[restrict])
{
- return __posix_spawnx(res, file, __execvpe, fa, attr, argv, envp);
+ posix_spawnattr_t spawnp_attr = { 0 };
+ if (attr) spawnp_attr = *attr;
+ spawnp_attr.__fn = (void *)__execvpe;
+ return posix_spawn(res, file, fa, &spawnp_attr, argv, envp);
}