freebsd-dev/usr.bin/mail/popen.c

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/*-
* SPDX-License-Identifier: BSD-3-Clause
*
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* 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
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* 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.
*/
#ifndef lint
#if 0
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static char sccsid[] = "@(#)popen.c 8.1 (Berkeley) 6/6/93";
#endif
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#endif /* not lint */
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#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
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#include "rcv.h"
#include <sys/wait.h>
#include <fcntl.h>
#include <errno.h>
#include <stdarg.h>
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#include "extern.h"
#define READ 0
#define WRITE 1
struct fp {
FILE *fp;
int pipe;
pid_t pid;
struct fp *link;
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};
static struct fp *fp_head;
struct child {
pid_t pid;
char done;
char free;
int status;
struct child *link;
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};
static struct child *child, *child_freelist = NULL;
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static void delchild(struct child *);
static pid_t file_pid(FILE *);
static pid_t start_commandv(char *, sigset_t *, int, int, va_list);
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FILE *
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Fopen(const char *path, const char *mode)
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{
FILE *fp;
if ((fp = fopen(path, mode)) != NULL) {
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register_file(fp, 0, 0);
(void)fcntl(fileno(fp), F_SETFD, 1);
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}
return (fp);
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}
FILE *
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Fdopen(int fd, const char *mode)
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{
FILE *fp;
if ((fp = fdopen(fd, mode)) != NULL) {
register_file(fp, 0, 0);
(void)fcntl(fileno(fp), F_SETFD, 1);
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}
return (fp);
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}
int
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Fclose(FILE *fp)
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{
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unregister_file(fp);
return (fclose(fp));
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}
FILE *
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Popen(char *cmd, const char *mode)
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{
int p[2];
int myside, hisside, fd0, fd1;
pid_t pid;
sigset_t nset;
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FILE *fp;
if (pipe(p) < 0)
return (NULL);
(void)fcntl(p[READ], F_SETFD, 1);
(void)fcntl(p[WRITE], F_SETFD, 1);
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if (*mode == 'r') {
myside = p[READ];
hisside = fd0 = fd1 = p[WRITE];
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} else {
myside = p[WRITE];
hisside = fd0 = p[READ];
fd1 = -1;
}
(void)sigemptyset(&nset);
pid = start_command(value("SHELL"), &nset, fd0, fd1, "-c", cmd, NULL);
if (pid < 0) {
(void)close(p[READ]);
(void)close(p[WRITE]);
return (NULL);
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}
(void)close(hisside);
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if ((fp = fdopen(myside, mode)) != NULL)
register_file(fp, 1, pid);
return (fp);
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}
int
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Pclose(FILE *ptr)
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{
int i;
sigset_t nset, oset;
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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);
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i = wait_child(i);
(void)sigprocmask(SIG_SETMASK, &oset, NULL);
return (i);
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}
void
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close_all_files(void)
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{
while (fp_head != NULL)
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if (fp_head->pipe)
(void)Pclose(fp_head->fp);
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else
(void)Fclose(fp_head->fp);
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}
void
register_file(FILE *fp, int pipe, pid_t pid)
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{
struct fp *fpp;
if ((fpp = malloc(sizeof(*fpp))) == NULL)
err(1, "Out of memory");
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fpp->fp = fp;
fpp->pipe = pipe;
fpp->pid = pid;
fpp->link = fp_head;
fp_head = fpp;
}
void
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unregister_file(FILE *fp)
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{
struct fp **pp, *p;
for (pp = &fp_head; (p = *pp) != NULL; pp = &p->link)
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if (p->fp == fp) {
*pp = p->link;
(void)free(p);
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return;
}
errx(1, "Invalid file pointer");
/*NOTREACHED*/
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}
pid_t
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file_pid(FILE *fp)
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{
struct fp *p;
for (p = fp_head; p != NULL; p = p->link)
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if (p->fp == fp)
return (p->pid);
errx(1, "Invalid file pointer");
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/*NOTREACHED*/
}
/*
* 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.
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* 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".
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*/
static pid_t
start_commandv(char *cmd, sigset_t *nset, int infd, int outfd, va_list args)
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{
pid_t pid;
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if ((pid = fork()) < 0) {
warn("fork");
return (-1);
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}
if (pid == 0) {
char *argv[100];
int i = getrawlist(cmd, argv, sizeof(argv) / sizeof(*argv));
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while ((argv[i++] = va_arg(args, char *)))
;
argv[i] = NULL;
prepare_child(nset, infd, outfd);
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execvp(argv[0], argv);
warn("%s", argv[0]);
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_exit(1);
}
return (pid);
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}
int
run_command(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);
}
int
start_command(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;
}
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void
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prepare_child(sigset_t *nset, int infd, int outfd)
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{
int i;
sigset_t eset;
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/*
* All file descriptors other than 0, 1, and 2 are supposed to be
* close-on-exec.
*/
if (infd >= 0)
dup2(infd, 0);
if (outfd >= 0)
dup2(outfd, 1);
for (i = 1; i < NSIG; i++)
if (nset != NULL && 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);
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}
int
wait_command(pid_t pid)
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{
if (wait_child(pid) < 0) {
printf("Fatal error in process.\n");
return (-1);
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}
return (0);
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}
static struct child *
findchild(pid_t pid, int dont_alloc)
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{
struct child **cpp;
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for (cpp = &child; *cpp != NULL && (*cpp)->pid != pid;
cpp = &(*cpp)->link)
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;
if (*cpp == NULL) {
if (dont_alloc)
return(NULL);
if (child_freelist) {
*cpp = child_freelist;
child_freelist = (*cpp)->link;
} else {
*cpp = malloc(sizeof(struct child));
if (*cpp == NULL)
err(1, "malloc");
}
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(*cpp)->pid = pid;
(*cpp)->done = (*cpp)->free = 0;
(*cpp)->link = NULL;
}
return (*cpp);
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}
static void
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delchild(struct child *cp)
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{
struct child **cpp;
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for (cpp = &child; *cpp != cp; cpp = &(*cpp)->link)
;
*cpp = cp->link;
cp->link = child_freelist;
child_freelist = cp;
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}
/*ARGSUSED*/
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void
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sigchild(int signo __unused)
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{
pid_t pid;
int status;
struct child *cp;
int save_errno;
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save_errno = errno;
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while ((pid = waitpid(-1, &status, WNOHANG)) > 0) {
cp = findchild(pid, 1);
if (cp == NULL)
continue;
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if (cp->free)
delchild(cp);
else {
cp->done = 1;
cp->status = status;
}
}
errno = save_errno;
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}
int wait_status;
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/*
* Wait for a specific child to die.
*/
int
wait_child(pid_t pid)
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{
struct child *cp;
sigset_t nset, oset;
pid_t rv = 0;
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(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;
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}
/*
* Mark a child as don't care.
*/
void
free_child(pid_t pid)
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{
struct child *cp;
sigset_t nset, oset;
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(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);
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}