From fe61a7aa53e68e8a17b5eb8d502e6fa314139ced Mon Sep 17 00:00:00 2001 From: Rich Felker Date: Mon, 10 Sep 2018 16:13:29 -0400 Subject: 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. --- src/process/posix_spawn.c | 18 +++++------------- src/process/posix_spawnp.c | 10 ++++------ 2 files changed, 9 insertions(+), 19 deletions(-) (limited to 'src') 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); } -- cgit v1.2.1