diff options
Diffstat (limited to 'libio/iopopen.c')
-rw-r--r-- | libio/iopopen.c | 179 |
1 files changed, 43 insertions, 136 deletions
diff --git a/libio/iopopen.c b/libio/iopopen.c index 9ddde23494..2eff45b4c8 100644 --- a/libio/iopopen.c +++ b/libio/iopopen.c @@ -1,4 +1,4 @@ -/* Copyright (C) 1993-2016 Free Software Foundation, Inc. +/* Copyright (C) 1993-2018 Free Software Foundation, Inc. This file is part of the GNU C Library. Written by Per Bothner <bothner@cygnus.com>. @@ -25,68 +25,22 @@ This exception applies to code released by its copyright holders in files containing the exception. */ -#ifndef _POSIX_SOURCE -# define _POSIX_SOURCE -#endif #include "libioP.h" #include <fcntl.h> #include <signal.h> #include <unistd.h> #include <stdlib.h> -#ifdef _LIBC -# include <shlib-compat.h> -# include <not-cancel.h> -#endif +#include <shlib-compat.h> +#include <not-cancel.h> #include <sys/types.h> #include <sys/wait.h> #include <kernel-features.h> -#ifndef _IO_fork -#ifdef _LIBC -#define _IO_fork __fork -#else -#define _IO_fork fork /* defined in libiberty, if needed */ -#endif -extern _IO_pid_t _IO_fork (void) __THROW; -#endif - -#ifndef _IO_dup2 -#ifdef _LIBC -#define _IO_dup2 __dup2 -#else -#define _IO_dup2 dup2 -#endif -extern int _IO_dup2 (int fd, int fd2) __THROW; -#endif - -#ifndef _IO_waitpid -#ifdef _LIBC -#define _IO_waitpid waitpid_not_cancel -#else -#define _IO_waitpid waitpid -#endif -#endif - -#ifndef _IO_execl -#define _IO_execl execl -#endif -#ifndef _IO__exit -#define _IO__exit _exit -#endif - -#ifndef _IO_close -#ifdef _LIBC -#define _IO_close close_not_cancel -#else -#define _IO_close close -#endif -#endif - struct _IO_proc_file { struct _IO_FILE_plus file; /* Following fields must match those in class procbuf (procbuf.h) */ - _IO_pid_t pid; + pid_t pid; struct _IO_proc_file *next; }; typedef struct _IO_proc_file _IO_proc_file; @@ -105,13 +59,13 @@ unlock (void *not_used) } #endif -_IO_FILE * -_IO_new_proc_open (_IO_FILE *fp, const char *command, const char *mode) +FILE * +_IO_new_proc_open (FILE *fp, const char *command, const char *mode) { int read_or_write; int parent_end, child_end; int pipe_fds[2]; - _IO_pid_t child_pid; + pid_t child_pid; int do_read = 0; int do_write = 0; @@ -140,29 +94,17 @@ _IO_new_proc_open (_IO_FILE *fp, const char *command, const char *mode) if (_IO_file_is_open (fp)) return NULL; -#ifdef O_CLOEXEC -# ifndef __ASSUME_PIPE2 - if (__have_pipe2 >= 0) -# endif - { - int r = __pipe2 (pipe_fds, O_CLOEXEC); -# ifndef __ASSUME_PIPE2 - if (__have_pipe2 == 0) - __have_pipe2 = r != -1 || errno != ENOSYS ? 1 : -1; - - if (__have_pipe2 > 0) -# endif - if (r < 0) - return NULL; - } -#endif -#ifndef __ASSUME_PIPE2 -# ifdef O_CLOEXEC - if (__have_pipe2 < 0) -# endif - if (__pipe (pipe_fds) < 0) - return NULL; -#endif + /* Atomically set the O_CLOEXEC flag for the pipe end used by the + child process (to avoid leaking the file descriptor in case of a + concurrent fork). This is later reverted in the child process. + When popen returns, the parent pipe end can be O_CLOEXEC or not, + depending on the 'e' open mode, but there is only one flag which + controls both descriptors. The parent end is adjusted below, + after creating the child process. (In the child process, the + parent end should be closed on execve, so O_CLOEXEC remains set + there.) */ + if (__pipe2 (pipe_fds, O_CLOEXEC) < 0) + return NULL; if (do_read) { @@ -177,78 +119,46 @@ _IO_new_proc_open (_IO_FILE *fp, const char *command, const char *mode) read_or_write = _IO_NO_READS; } - ((_IO_proc_file *) fp)->pid = child_pid = _IO_fork (); + ((_IO_proc_file *) fp)->pid = child_pid = __fork (); if (child_pid == 0) { int child_std_end = do_read ? 1 : 0; struct _IO_proc_file *p; -#ifndef __ASSUME_PIPE2 - /* If we have pipe2 the descriptor is marked for close-on-exec. */ - _IO_close (parent_end); -#endif if (child_end != child_std_end) - { - _IO_dup2 (child_end, child_std_end); -#ifndef __ASSUME_PIPE2 - _IO_close (child_end); -#endif - } -#ifdef O_CLOEXEC + __dup2 (child_end, child_std_end); else - { - /* The descriptor is already the one we will use. But it must - not be marked close-on-exec. Undo the effects. */ -# ifndef __ASSUME_PIPE2 - if (__have_pipe2 > 0) -# endif - __fcntl (child_end, F_SETFD, 0); - } -#endif + /* The descriptor is already the one we will use. But it must + not be marked close-on-exec. Undo the effects. */ + __fcntl (child_end, F_SETFD, 0); /* POSIX.2: "popen() shall ensure that any streams from previous popen() calls that remain open in the parent process are closed in the new child process." */ for (p = proc_file_chain; p; p = p->next) { - int fd = _IO_fileno ((_IO_FILE *) p); + int fd = _IO_fileno ((FILE *) p); /* If any stream from previous popen() calls has fileno child_std_end, it has been already closed by the dup2 syscall above. */ if (fd != child_std_end) - _IO_close (fd); + __close_nocancel (fd); } - _IO_execl ("/bin/sh", "sh", "-c", command, (char *) 0); - _IO__exit (127); + execl ("/bin/sh", "sh", "-c", command, (char *) 0); + _exit (127); } - _IO_close (child_end); + __close_nocancel (child_end); if (child_pid < 0) { - _IO_close (parent_end); + __close_nocancel (parent_end); return NULL; } - if (do_cloexec) - { -#ifndef __ASSUME_PIPE2 -# ifdef O_CLOEXEC - if (__have_pipe2 < 0) -# endif - __fcntl (parent_end, F_SETFD, FD_CLOEXEC); -#endif - } - else - { -#ifdef O_CLOEXEC - /* Undo the effects of the pipe2 call which set the - close-on-exec flag. */ -# ifndef __ASSUME_PIPE2 - if (__have_pipe2 > 0) -# endif - __fcntl (parent_end, F_SETFD, 0); -#endif - } + if (!do_cloexec) + /* Undo the effects of the pipe2 call which set the + close-on-exec flag. */ + __fcntl (parent_end, F_SETFD, 0); _IO_fileno (fp) = parent_end; @@ -268,7 +178,7 @@ _IO_new_proc_open (_IO_FILE *fp, const char *command, const char *mode) return fp; } -_IO_FILE * +FILE * _IO_new_popen (const char *command, const char *mode) { struct locked_FILE @@ -278,7 +188,7 @@ _IO_new_popen (const char *command, const char *mode) _IO_lock_t lock; #endif } *new_f; - _IO_FILE *fp; + FILE *fp; new_f = (struct locked_FILE *) malloc (sizeof (struct locked_FILE)); if (new_f == NULL) @@ -287,26 +197,23 @@ _IO_new_popen (const char *command, const char *mode) new_f->fpx.file.file._lock = &new_f->lock; #endif fp = &new_f->fpx.file.file; - _IO_init (fp, 0); + _IO_init_internal (fp, 0); _IO_JUMPS (&new_f->fpx.file) = &_IO_proc_jumps; - _IO_new_file_init (&new_f->fpx.file); -#if !_IO_UNIFIED_JUMPTABLES - new_f->fpx.file.vtable = NULL; -#endif + _IO_new_file_init_internal (&new_f->fpx.file); if (_IO_new_proc_open (fp, command, mode) != NULL) - return (_IO_FILE *) &new_f->fpx.file; + return (FILE *) &new_f->fpx.file; _IO_un_link (&new_f->fpx.file); free (new_f); return NULL; } int -_IO_new_proc_close (_IO_FILE *fp) +_IO_new_proc_close (FILE *fp) { /* This is not name-space clean. FIXME! */ int wstatus; _IO_proc_file **ptr = &proc_file_chain; - _IO_pid_t wait_pid; + pid_t wait_pid; int status = -1; /* Unlink from proc_file_chain. */ @@ -328,7 +235,7 @@ _IO_new_proc_close (_IO_FILE *fp) _IO_cleanup_region_end (0); #endif - if (status < 0 || _IO_close (_IO_fileno(fp)) < 0) + if (status < 0 || __close_nocancel (_IO_fileno(fp)) < 0) return -1; /* POSIX.2 Rationale: "Some historical implementations either block or ignore the signals SIGINT, SIGQUIT, and SIGHUP while waiting @@ -336,7 +243,7 @@ _IO_new_proc_close (_IO_FILE *fp) described in POSIX.2, such implementations are not conforming." */ do { - wait_pid = _IO_waitpid (((_IO_proc_file *) fp)->pid, &wstatus, 0); + wait_pid = __waitpid_nocancel (((_IO_proc_file *) fp)->pid, &wstatus, 0); } while (wait_pid == -1 && errno == EINTR); if (wait_pid == -1) @@ -344,7 +251,7 @@ _IO_new_proc_close (_IO_FILE *fp) return wstatus; } -static const struct _IO_jump_t _IO_proc_jumps = { +static const struct _IO_jump_t _IO_proc_jumps libio_vtable = { JUMP_INIT_DUMMY, JUMP_INIT(finish, _IO_new_file_finish), JUMP_INIT(overflow, _IO_new_file_overflow), |