diff options
Diffstat (limited to 'sysdeps/posix/spawni.c')
| -rw-r--r-- | sysdeps/posix/spawni.c | 357 |
1 files changed, 180 insertions, 177 deletions
diff --git a/sysdeps/posix/spawni.c b/sysdeps/posix/spawni.c index 043266dcd3..b138ab4393 100644 --- a/sysdeps/posix/spawni.c +++ b/sysdeps/posix/spawni.c @@ -1,5 +1,5 @@ /* Guts of POSIX spawn interface. Generic POSIX.1 version. - Copyright (C) 2000-2016 Free Software Foundation, Inc. + Copyright (C) 2000-2018 Free Software Foundation, Inc. This file is part of the GNU C Library. The GNU C Library is free software; you can redistribute it and/or @@ -16,20 +16,23 @@ License along with the GNU C Library; if not, see <http://www.gnu.org/licenses/>. */ -#include <errno.h> +#include <spawn.h> +#include <assert.h> #include <fcntl.h> #include <paths.h> -#include <spawn.h> -#include <stdbool.h> -#include <stdlib.h> #include <string.h> -#include <unistd.h> -#include <signal.h> #include <sys/resource.h> -#include "spawn_int.h" +#include <sys/wait.h> +#include <sys/param.h> +#include <sys/mman.h> #include <not-cancel.h> #include <local-setxid.h> #include <shlib-compat.h> +#include <nptl/pthreadP.h> +#include <dl-sysdep.h> +#include <libc-pointer-arith.h> +#include <ldsodefs.h> +#include "spawn_int.h" /* The Unix standard contains a long explanation of the way to signal @@ -39,93 +42,59 @@ normal program exit with the exit code 127. */ #define SPAWN_ERROR 127 - -/* The file is accessible but it is not an executable file. Invoke - the shell to interpret it as a script. */ -static void -internal_function -script_execute (const char *file, char *const argv[], char *const envp[]) +struct posix_spawn_args { - /* Count the arguments. */ - int argc = 0; - while (argv[argc++]) - ; - - /* Construct an argument list for the shell. */ - { - char *new_argv[argc + 1]; - new_argv[0] = (char *) _PATH_BSHELL; - new_argv[1] = (char *) file; - while (argc > 1) - { - new_argv[argc] = argv[argc - 1]; - --argc; - } - - /* Execute the shell. */ - __execve (new_argv[0], new_argv, envp); - } -} - -static inline void -maybe_script_execute (const char *file, char *const argv[], char *const envp[], - int xflags) + sigset_t oldmask; + const char *file; + int (*exec) (const char *, char *const *, char *const *); + const posix_spawn_file_actions_t *fa; + const posix_spawnattr_t *restrict attr; + char *const *argv; + ptrdiff_t argc; + char *const *envp; + int xflags; + int pipe[2]; +}; + +/* Older version requires that shell script without shebang definition + to be called explicitly using /bin/sh (_PATH_BSHELL). */ +static void +maybe_script_execute (struct posix_spawn_args *args) { if (SHLIB_COMPAT (libc, GLIBC_2_2, GLIBC_2_15) - && (xflags & SPAWN_XFLAGS_TRY_SHELL) - && errno == ENOEXEC) - script_execute (file, argv, envp); -} - -/* Spawn a new process executing PATH with the attributes describes in *ATTRP. - Before running the process perform the actions described in FILE-ACTIONS. */ -int -__spawni (pid_t *pid, const char *file, - const posix_spawn_file_actions_t *file_actions, - const posix_spawnattr_t *attrp, char *const argv[], - char *const envp[], int xflags) -{ - pid_t new_pid; - char *path, *p, *name; - size_t len; - size_t pathlen; - - /* Do this once. */ - short int flags = attrp == NULL ? 0 : attrp->__flags; - - /* Generate the new process. */ - if ((flags & POSIX_SPAWN_USEVFORK) != 0 - /* If no major work is done, allow using vfork. Note that we - might perform the path searching. But this would be done by - a call to execvp(), too, and such a call must be OK according - to POSIX. */ - || ((flags & (POSIX_SPAWN_SETSIGMASK | POSIX_SPAWN_SETSIGDEF - | POSIX_SPAWN_SETSCHEDPARAM | POSIX_SPAWN_SETSCHEDULER - | POSIX_SPAWN_SETPGROUP | POSIX_SPAWN_RESETIDS)) == 0 - && file_actions == NULL)) - new_pid = __vfork (); - else - new_pid = __fork (); - - if (new_pid != 0) + && (args->xflags & SPAWN_XFLAGS_TRY_SHELL) && errno == ENOEXEC) { - if (new_pid < 0) - return errno; - - /* The call was successful. Store the PID if necessary. */ - if (pid != NULL) - *pid = new_pid; + char *const *argv = args->argv; + ptrdiff_t argc = args->argc; + + /* Construct an argument list for the shell. */ + char *new_argv[argc + 1]; + new_argv[0] = (char *) _PATH_BSHELL; + new_argv[1] = (char *) args->file; + if (argc > 1) + memcpy (new_argv + 2, argv + 1, argc * sizeof(char *)); + else + new_argv[2] = NULL; - return 0; + /* Execute the shell. */ + args->exec (new_argv[0], new_argv, args->envp); } +} - /* Set signal mask. */ - if ((flags & POSIX_SPAWN_SETSIGMASK) != 0 - && __sigprocmask (SIG_SETMASK, &attrp->__ss, NULL) != 0) - _exit (SPAWN_ERROR); +/* Function used in the clone call to setup the signals mask, posix_spawn + attributes, and file actions. */ +static int +__spawni_child (void *arguments) +{ + struct posix_spawn_args *args = arguments; + const posix_spawnattr_t *restrict attr = args->attr; + const posix_spawn_file_actions_t *file_actions = args->fa; + int ret; + + __close (args->pipe[0]); /* Set signal default action. */ - if ((flags & POSIX_SPAWN_SETSIGDEF) != 0) + if ((attr->__flags & POSIX_SPAWN_SETSIGDEF) != 0) { /* We have to iterate over all signals. This could possibly be done better but it requires system specific solutions since @@ -138,37 +107,41 @@ __spawni (pid_t *pid, const char *file, sa.sa_handler = SIG_DFL; for (sig = 1; sig <= _NSIG; ++sig) - if (__sigismember (&attrp->__sd, sig) != 0 + if (__sigismember (&attr->__sd, sig) != 0 && __sigaction (sig, &sa, NULL) != 0) - _exit (SPAWN_ERROR); - + goto fail; } #ifdef _POSIX_PRIORITY_SCHEDULING /* Set the scheduling algorithm and parameters. */ - if ((flags & (POSIX_SPAWN_SETSCHEDPARAM | POSIX_SPAWN_SETSCHEDULER)) + if ((attr->__flags & (POSIX_SPAWN_SETSCHEDPARAM | POSIX_SPAWN_SETSCHEDULER)) == POSIX_SPAWN_SETSCHEDPARAM) { - if (__sched_setparam (0, &attrp->__sp) == -1) - _exit (SPAWN_ERROR); + if (__sched_setparam (0, &attr->__sp) == -1) + goto fail; } - else if ((flags & POSIX_SPAWN_SETSCHEDULER) != 0) + else if ((attr->__flags & POSIX_SPAWN_SETSCHEDULER) != 0) { - if (__sched_setscheduler (0, attrp->__policy, &attrp->__sp) == -1) - _exit (SPAWN_ERROR); + if (__sched_setscheduler (0, attr->__policy, &attr->__sp) == -1) + goto fail; } #endif + /* Set the process session ID. */ + if ((attr->__flags & POSIX_SPAWN_SETSID) != 0 + && __setsid () < 0) + goto fail; + /* Set the process group ID. */ - if ((flags & POSIX_SPAWN_SETPGROUP) != 0 - && __setpgid (0, attrp->__pgrp) != 0) - _exit (SPAWN_ERROR); + if ((attr->__flags & POSIX_SPAWN_SETPGROUP) != 0 + && __setpgid (0, attr->__pgrp) != 0) + goto fail; /* Set the effective user and group IDs. */ - if ((flags & POSIX_SPAWN_RESETIDS) != 0 + if ((attr->__flags & POSIX_SPAWN_RESETIDS) != 0 && (local_seteuid (__getuid ()) != 0 - || local_setegid (__getgid ()) != 0)) - _exit (SPAWN_ERROR); + || local_setegid (__getgid ())) != 0) + goto fail; /* Execute the file actions. */ if (file_actions != NULL) @@ -184,9 +157,9 @@ __spawni (pid_t *pid, const char *file, switch (action->tag) { case spawn_do_close: - if (close_not_cancel (action->action.close_action.fd) != 0) + if (__close_nocancel (action->action.close_action.fd) != 0) { - if (! have_fdlimit) + if (have_fdlimit == 0) { __getrlimit64 (RLIMIT_NOFILE, &fdlimit); have_fdlimit = true; @@ -195,33 +168,37 @@ __spawni (pid_t *pid, const char *file, /* Only signal errors for file descriptors out of range. */ if (action->action.close_action.fd < 0 || action->action.close_action.fd >= fdlimit.rlim_cur) - /* Signal the error. */ - _exit (SPAWN_ERROR); + goto fail; } break; case spawn_do_open: { - int new_fd = open_not_cancel (action->action.open_action.path, + /* POSIX states that if fildes was already an open file descriptor, + it shall be closed before the new file is opened. This avoid + pontential issues when posix_spawn plus addopen action is called + with the process already at maximum number of file descriptor + opened and also for multiple actions on single-open special + paths (like /dev/watchdog). */ + __close_nocancel (action->action.open_action.fd); + + int new_fd = __open_nocancel (action->action.open_action.path, action->action.open_action.oflag | O_LARGEFILE, action->action.open_action.mode); if (new_fd == -1) - /* The `open' call failed. */ - _exit (SPAWN_ERROR); + goto fail; /* Make sure the desired file descriptor is used. */ if (new_fd != action->action.open_action.fd) { if (__dup2 (new_fd, action->action.open_action.fd) != action->action.open_action.fd) - /* The `dup2' call failed. */ - _exit (SPAWN_ERROR); + goto fail; - if (close_not_cancel (new_fd) != 0) - /* The `close' call failed. */ - _exit (SPAWN_ERROR); + if (__close_nocancel (new_fd) != 0) + goto fail; } } break; @@ -230,85 +207,111 @@ __spawni (pid_t *pid, const char *file, if (__dup2 (action->action.dup2_action.fd, action->action.dup2_action.newfd) != action->action.dup2_action.newfd) - /* The `dup2' call failed. */ - _exit (SPAWN_ERROR); + goto fail; break; } } } - if ((xflags & SPAWN_XFLAGS_USE_PATH) == 0 || strchr (file, '/') != NULL) - { - /* The FILE parameter is actually a path. */ - __execve (file, argv, envp); + /* Set the initial signal mask of the child if POSIX_SPAWN_SETSIGMASK + is set, otherwise restore the previous one. */ + __sigprocmask (SIG_SETMASK, (attr->__flags & POSIX_SPAWN_SETSIGMASK) + ? &attr->__ss : &args->oldmask, 0); + + args->exec (args->file, args->argv, args->envp); + + /* This is compatibility function required to enable posix_spawn run + script without shebang definition for older posix_spawn versions + (2.15). */ + maybe_script_execute (args); + +fail: + /* errno should have an appropriate non-zero value; otherwise, + there's a bug in glibc or the kernel. For lack of an error code + (EINTERNALBUG) describing that, use ECHILD. Another option would + be to set args->err to some negative sentinel and have the parent + abort(), but that seems needlessly harsh. */ + ret = errno ? : ECHILD; + if (ret) + /* Since sizeof errno < PIPE_BUF, the write is atomic. */ + while (__write_nocancel (args->pipe[1], &ret, sizeof (ret)) < 0); - maybe_script_execute (file, argv, envp, xflags); + _exit (SPAWN_ERROR); +} - /* Oh, oh. `execve' returns. This is bad. */ - _exit (SPAWN_ERROR); - } +/* Spawn a new process executing PATH with the attributes describes in *ATTRP. + Before running the process perform the actions described in FILE-ACTIONS. */ +int +__spawnix (pid_t *pid, const char *file, + const posix_spawn_file_actions_t *file_actions, + const posix_spawnattr_t *attrp, char *const argv[], + char *const envp[], int xflags, + int (*exec) (const char *, char *const *, char *const *)) +{ + struct posix_spawn_args args; + int ec; - /* We have to search for FILE on the path. */ - path = getenv ("PATH"); - if (path == NULL) - { - /* There is no `PATH' in the environment. - The default search path is the current directory - followed by the path `confstr' returns for `_CS_PATH'. */ - len = confstr (_CS_PATH, (char *) NULL, 0); - path = (char *) __alloca (1 + len); - path[0] = ':'; - (void) confstr (_CS_PATH, path + 1, len); - } + if (__pipe2 (args.pipe, O_CLOEXEC)) + return errno; - len = strlen (file) + 1; - pathlen = strlen (path); - name = __alloca (pathlen + len + 1); - /* Copy the file name at the top. */ - name = (char *) memcpy (name + pathlen + 1, file, len); - /* And add the slash. */ - *--name = '/'; + /* Disable asynchronous cancellation. */ + int state; + __libc_ptf_call (__pthread_setcancelstate, + (PTHREAD_CANCEL_DISABLE, &state), 0); - p = path; - do - { - char *startp; + ptrdiff_t argc = 0; + ptrdiff_t limit = INT_MAX - 1; + while (argv[argc++] != NULL) + if (argc == limit) + { + errno = E2BIG; + return errno; + } - path = p; - p = __strchrnul (path, ':'); + args.file = file; + args.exec = exec; + args.fa = file_actions; + args.attr = attrp ? attrp : &(const posix_spawnattr_t) { 0 }; + args.argv = argv; + args.argc = argc; + args.envp = envp; + args.xflags = xflags; - if (p == path) - /* Two adjacent colons, or a colon at the beginning or the end - of `PATH' means to search the current directory. */ - startp = name + 1; + /* Generate the new process. */ + pid_t new_pid = __fork (); + + if (new_pid == 0) + __spawni_child (&args); + else if (new_pid > 0) + { + __close (args.pipe[1]); + + if (__read (args.pipe[0], &ec, sizeof ec) != sizeof ec) + ec = 0; else - startp = (char *) memcpy (name - (p - path), path, p - path); + __waitpid (new_pid, &(int) { 0 }, 0); + } + else + ec = errno; - /* Try to execute this name. If it works, execv will not return. */ - __execve (startp, argv, envp); + __close (args.pipe[0]); - maybe_script_execute (startp, argv, envp, xflags); + if ((ec == 0) && (pid != NULL)) + *pid = new_pid; - switch (errno) - { - case EACCES: - case ENOENT: - case ESTALE: - case ENOTDIR: - /* Those errors indicate the file is missing or not executable - by us, in which case we want to just try the next path - directory. */ - break; - - default: - /* Some other error means we found an executable file, but - something went wrong executing it; return the error to our - caller. */ - _exit (SPAWN_ERROR); - } - } - while (*p++ != '\0'); + __libc_ptf_call (__pthread_setcancelstate, (state, NULL), 0); - /* Return with an error. */ - _exit (SPAWN_ERROR); + return ec; +} + +int +__spawni (pid_t * pid, const char *file, + const posix_spawn_file_actions_t * acts, + const posix_spawnattr_t * attrp, char *const argv[], + char *const envp[], int xflags) +{ + /* It uses __execvpex to avoid run ENOEXEC in non compatibility mode (it + will be handled by maybe_script_execute). */ + return __spawnix (pid, file, acts, attrp, argv, envp, xflags, + xflags & SPAWN_XFLAGS_USE_PATH ? __execvpex : __execve); } |