NetBSD-5.0.2/usr.bin/mail/popen.c
/* $NetBSD: popen.c,v 1.24 2007/10/30 02:28:31 christos Exp $ */
/*
* Copyright (c) 1980, 1993
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
#ifndef lint
#if 0
static char sccsid[] = "@(#)popen.c 8.1 (Berkeley) 6/6/93";
#else
__RCSID("$NetBSD: popen.c,v 1.24 2007/10/30 02:28:31 christos Exp $");
#endif
#endif /* not lint */
#include <errno.h>
#include <fcntl.h>
#include <stdarg.h>
#include <util.h>
#include <sys/wait.h>
#include "rcv.h"
#include "extern.h"
#define READ 0
#define WRITE 1
struct fp {
FILE *fp;
int pipe;
pid_t pid;
struct fp *link;
};
static struct fp *fp_head;
struct child {
pid_t pid;
char done;
char free;
int status;
struct child *link;
};
static struct child *child, *child_freelist = NULL;
#if 0 /* XXX - debugging stuff. This should go away eventually! */
static void
show_one_file(FILE *fo, struct fp *fpp)
{
(void)fprintf(fo, ">>> fp: %p, pipe: %d, pid: %d, link: %p\n",
fpp->fp, fpp->pipe, fpp->pid, fpp->link);
}
void show_all_files(FILE *fo);
__unused
PUBLIC void
show_all_files(FILE *fo)
{
struct fp *fpp;
(void)fprintf(fo, ">> FILES\n");
for (fpp = fp_head; fpp; fpp = fpp->link)
show_one_file(fo, fpp);
(void)fprintf(fo, ">> -------\n");
(void)fflush(fo);
}
#endif /* end debugging stuff */
static void
unregister_file(FILE *fp)
{
struct fp **pp, *p;
for (pp = &fp_head; (p = *pp) != NULL; pp = &p->link)
if (p->fp == fp) {
*pp = p->link;
(void)free(p);
return;
}
errx(1, "Invalid file pointer");
}
PUBLIC void
register_file(FILE *fp, int pipefd, pid_t pid)
{
struct fp *fpp;
fpp = emalloc(sizeof(*fpp));
fpp->fp = fp;
fpp->pipe = pipefd;
fpp->pid = pid;
fpp->link = fp_head;
fp_head = fpp;
}
PUBLIC FILE *
Fopen(const char *fn, const char *mode)
{
FILE *fp;
if ((fp = fopen(fn, mode)) != NULL) {
register_file(fp, 0, 0);
(void)fcntl(fileno(fp), F_SETFD, FD_CLOEXEC);
}
return fp;
}
PUBLIC FILE *
Fdopen(int fd, const char *mode)
{
FILE *fp;
if ((fp = fdopen(fd, mode)) != NULL) {
register_file(fp, 0, 0);
(void)fcntl(fileno(fp), F_SETFD, FD_CLOEXEC);
}
return fp;
}
PUBLIC int
Fclose(FILE *fp)
{
unregister_file(fp);
return fclose(fp);
}
PUBLIC void
prepare_child(sigset_t *nset, int infd, int outfd)
{
int i;
sigset_t eset;
/*
* All file descriptors other than 0, 1, and 2 are supposed to be
* close-on-exec.
*/
if (infd > 0) {
(void)dup2(infd, 0);
} else if (infd != 0) {
/* we don't want the child stealing my stdin input */
(void)close(0);
(void)open(_PATH_DEVNULL, O_RDONLY, 0);
}
if (outfd >= 0 && outfd != 1)
(void)dup2(outfd, 1);
if (nset == NULL)
return;
if (nset != NULL) {
for (i = 1; i < NSIG; i++)
if (sigismember(nset, i))
(void)signal(i, SIG_IGN);
}
if (nset == NULL || !sigismember(nset, SIGINT))
(void)signal(SIGINT, SIG_DFL);
(void)sigemptyset(&eset);
(void)sigprocmask(SIG_SETMASK, &eset, NULL);
}
/*
* Run a command without a shell, with optional arguments and splicing
* of stdin (-1 means none) and stdout. The command name can be a sequence
* of words.
* Signals must be handled by the caller.
* "nset" contains the signals to ignore in the new process.
* SIGINT is enabled unless it's in "nset".
*/
static pid_t
start_commandv(const char *cmd, sigset_t *nset, int infd, int outfd,
va_list args)
{
pid_t pid;
if ((pid = fork()) < 0) {
warn("fork");
return -1;
}
if (pid == 0) {
char *argv[100];
int i = getrawlist(cmd, argv, sizeof(argv)/ sizeof(*argv));
while ((argv[i++] = va_arg(args, char *)) != NULL)
continue;
argv[i] = NULL;
prepare_child(nset, infd, outfd);
(void)execvp(argv[0], argv);
warn("%s", argv[0]);
_exit(1);
}
return pid;
}
PUBLIC int
start_command(const char *cmd, sigset_t *nset, int infd, int outfd, ...)
{
va_list args;
int r;
va_start(args, outfd);
r = start_commandv(cmd, nset, infd, outfd, args);
va_end(args);
return r;
}
PUBLIC FILE *
Popen(const char *cmd, const char *mode)
{
int p[2];
int myside, hisside, fd0, fd1;
pid_t pid;
sigset_t nset;
FILE *fp;
char *shellcmd;
if (pipe(p) < 0)
return NULL;
(void)fcntl(p[READ], F_SETFD, FD_CLOEXEC);
(void)fcntl(p[WRITE], F_SETFD, FD_CLOEXEC);
if (*mode == 'r') {
myside = p[READ];
hisside = fd0 = fd1 = p[WRITE];
} else {
myside = p[WRITE];
hisside = fd0 = p[READ];
fd1 = -1;
}
(void)sigemptyset(&nset);
if ((shellcmd = value(ENAME_SHELL)) == NULL)
shellcmd = __UNCONST(_PATH_CSHELL);
pid = start_command(shellcmd, &nset, fd0, fd1, "-c", cmd, NULL);
if (pid < 0) {
(void)close(p[READ]);
(void)close(p[WRITE]);
return NULL;
}
(void)close(hisside);
if ((fp = fdopen(myside, mode)) != NULL)
register_file(fp, 1, pid);
return fp;
}
static struct child *
findchild(pid_t pid, int dont_alloc)
{
struct child **cpp;
for (cpp = &child; *cpp != NULL && (*cpp)->pid != pid;
cpp = &(*cpp)->link)
continue;
if (*cpp == NULL) {
if (dont_alloc)
return NULL;
if (child_freelist) {
*cpp = child_freelist;
child_freelist = (*cpp)->link;
} else
*cpp = emalloc(sizeof(**cpp));
(*cpp)->pid = pid;
(*cpp)->done = (*cpp)->free = 0;
(*cpp)->link = NULL;
}
return *cpp;
}
static void
delchild(struct child *cp)
{
struct child **cpp;
for (cpp = &child; *cpp != cp; cpp = &(*cpp)->link)
continue;
*cpp = cp->link;
cp->link = child_freelist;
child_freelist = cp;
}
/*
* Wait for a specific child to die.
*/
PUBLIC int
wait_child(pid_t pid)
{
struct child *cp;
sigset_t nset, oset;
pid_t rv = 0;
(void)sigemptyset(&nset);
(void)sigaddset(&nset, SIGCHLD);
(void)sigprocmask(SIG_BLOCK, &nset, &oset);
/*
* If we have not already waited on the pid (via sigchild)
* wait on it now. Otherwise, use the wait status stashed
* by sigchild.
*/
cp = findchild(pid, 1);
if (cp == NULL || !cp->done)
rv = waitpid(pid, &wait_status, 0);
else
wait_status = cp->status;
if (cp != NULL)
delchild(cp);
(void)sigprocmask(SIG_SETMASK, &oset, NULL);
if (rv == -1 || (WIFEXITED(wait_status) && WEXITSTATUS(wait_status)))
return -1;
else
return 0;
}
static pid_t
file_pid(FILE *fp)
{
struct fp *p;
for (p = fp_head; p; p = p->link)
if (p->fp == fp)
return p->pid;
errx(1, "Invalid file pointer");
/*NOTREACHED*/
}
PUBLIC int
Pclose(FILE *ptr)
{
int i;
sigset_t nset, oset;
i = file_pid(ptr);
unregister_file(ptr);
(void)fclose(ptr);
(void)sigemptyset(&nset);
(void)sigaddset(&nset, SIGINT);
(void)sigaddset(&nset, SIGHUP);
(void)sigprocmask(SIG_BLOCK, &nset, &oset);
i = wait_child(i);
(void)sigprocmask(SIG_SETMASK, &oset, NULL);
return i;
}
PUBLIC void
close_all_files(void)
{
while (fp_head)
if (fp_head->pipe)
(void)Pclose(fp_head->fp);
else
(void)Fclose(fp_head->fp);
}
PUBLIC FILE *
last_registered_file(int last_pipe)
{
struct fp *fpp;
if (last_pipe == 0)
return fp_head ? fp_head->fp : NULL;
for (fpp = fp_head; fpp; fpp = fpp->link)
if (fpp->pipe)
return fpp->fp;
return NULL;
}
PUBLIC void
close_top_files(FILE *fp_stop)
{
while (fp_head && fp_head->fp != fp_stop)
if (fp_head->pipe)
(void)Pclose(fp_head->fp);
else
(void)Fclose(fp_head->fp);
}
#ifdef MIME_SUPPORT
PUBLIC void
flush_files(FILE *fo, int only_pipes)
{
struct fp *fpp;
if (fo)
(void)fflush(fo);
for (fpp = fp_head; fpp; fpp = fpp->link)
if (!only_pipes || fpp->pipe)
(void)fflush(fpp->fp);
(void)fflush(stdout);
}
#endif /* MIME_SUPPORT */
static int
wait_command(pid_t pid)
{
if (wait_child(pid) < 0) {
(void)puts("Fatal error in process.");
return -1;
}
return 0;
}
PUBLIC int
run_command(const char *cmd, sigset_t *nset, int infd, int outfd, ...)
{
pid_t pid;
va_list args;
va_start(args, outfd);
pid = start_commandv(cmd, nset, infd, outfd, args);
va_end(args);
if (pid < 0)
return -1;
return wait_command(pid);
}
/*ARGSUSED*/
PUBLIC void
sigchild(int signo __unused)
{
pid_t pid;
int status;
struct child *cp;
int save_errno = errno;
while ((pid =
waitpid((pid_t)-1, &status, WNOHANG)) > 0) {
cp = findchild(pid, 1);
if (!cp)
continue;
if (cp->free)
delchild(cp);
else {
cp->done = 1;
cp->status = status;
}
}
errno = save_errno;
}
/*
* Mark a child as don't care.
*/
PUBLIC void
free_child(pid_t pid)
{
struct child *cp;
sigset_t nset, oset;
(void)sigemptyset(&nset);
(void)sigaddset(&nset, SIGCHLD);
(void)sigprocmask(SIG_BLOCK, &nset, &oset);
if ((cp = findchild(pid, 0)) != NULL) {
if (cp->done)
delchild(cp);
else
cp->free = 1;
}
(void)sigprocmask(SIG_SETMASK, &oset, NULL);
}