diff options
Diffstat (limited to 'lib/libc/gen/popen.c')
| -rw-r--r-- | lib/libc/gen/popen.c | 204 |
1 files changed, 204 insertions, 0 deletions
diff --git a/lib/libc/gen/popen.c b/lib/libc/gen/popen.c new file mode 100644 index 0000000..9e597b9 --- /dev/null +++ b/lib/libc/gen/popen.c @@ -0,0 +1,204 @@ +/* + * Copyright (c) 1988, 1993 + * The Regents of the University of California. All rights reserved. + * + * This code is derived from software written by Ken Arnold and + * published in UNIX Review, Vol. 6, No. 8. + * + * 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. + * 4. 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. + */ + +#if defined(LIBC_SCCS) && !defined(lint) +static char sccsid[] = "@(#)popen.c 8.3 (Berkeley) 5/3/95"; +#endif /* LIBC_SCCS and not lint */ +#include <sys/cdefs.h> +__FBSDID("$FreeBSD$"); + +#include "namespace.h" +#include <sys/param.h> +#include <sys/wait.h> + +#include <signal.h> +#include <errno.h> +#include <unistd.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <paths.h> +#include <pthread.h> +#include "un-namespace.h" +#include "libc_private.h" + +extern char **environ; + +static struct pid { + struct pid *next; + FILE *fp; + pid_t pid; +} *pidlist; +static pthread_mutex_t pidlist_mutex = PTHREAD_MUTEX_INITIALIZER; + +#define THREAD_LOCK() if (__isthreaded) _pthread_mutex_lock(&pidlist_mutex) +#define THREAD_UNLOCK() if (__isthreaded) _pthread_mutex_unlock(&pidlist_mutex) + +FILE * +popen(command, type) + const char *command, *type; +{ + struct pid *cur; + FILE *iop; + int pdes[2], pid, twoway; + char *argv[4]; + struct pid *p; + + /* + * Lite2 introduced two-way popen() pipes using _socketpair(). + * FreeBSD's pipe() is bidirectional, so we use that. + */ + if (strchr(type, '+')) { + twoway = 1; + type = "r+"; + } else { + twoway = 0; + if ((*type != 'r' && *type != 'w') || type[1]) + return (NULL); + } + if (pipe(pdes) < 0) + return (NULL); + + if ((cur = malloc(sizeof(struct pid))) == NULL) { + (void)_close(pdes[0]); + (void)_close(pdes[1]); + return (NULL); + } + + argv[0] = "sh"; + argv[1] = "-c"; + argv[2] = (char *)command; + argv[3] = NULL; + + THREAD_LOCK(); + switch (pid = vfork()) { + case -1: /* Error. */ + THREAD_UNLOCK(); + (void)_close(pdes[0]); + (void)_close(pdes[1]); + free(cur); + return (NULL); + /* NOTREACHED */ + case 0: /* Child. */ + if (*type == 'r') { + /* + * The _dup2() to STDIN_FILENO is repeated to avoid + * writing to pdes[1], which might corrupt the + * parent's copy. This isn't good enough in + * general, since the _exit() is no return, so + * the compiler is free to corrupt all the local + * variables. + */ + (void)_close(pdes[0]); + if (pdes[1] != STDOUT_FILENO) { + (void)_dup2(pdes[1], STDOUT_FILENO); + (void)_close(pdes[1]); + if (twoway) + (void)_dup2(STDOUT_FILENO, STDIN_FILENO); + } else if (twoway && (pdes[1] != STDIN_FILENO)) + (void)_dup2(pdes[1], STDIN_FILENO); + } else { + if (pdes[0] != STDIN_FILENO) { + (void)_dup2(pdes[0], STDIN_FILENO); + (void)_close(pdes[0]); + } + (void)_close(pdes[1]); + } + for (p = pidlist; p; p = p->next) { + (void)_close(fileno(p->fp)); + } + _execve(_PATH_BSHELL, argv, environ); + _exit(127); + /* NOTREACHED */ + } + THREAD_UNLOCK(); + + /* Parent; assume fdopen can't fail. */ + if (*type == 'r') { + iop = fdopen(pdes[0], type); + (void)_close(pdes[1]); + } else { + iop = fdopen(pdes[1], type); + (void)_close(pdes[0]); + } + + /* Link into list of file descriptors. */ + cur->fp = iop; + cur->pid = pid; + THREAD_LOCK(); + cur->next = pidlist; + pidlist = cur; + THREAD_UNLOCK(); + + return (iop); +} + +/* + * pclose -- + * Pclose returns -1 if stream is not associated with a `popened' command, + * if already `pclosed', or waitpid returns an error. + */ +int +pclose(iop) + FILE *iop; +{ + struct pid *cur, *last; + int pstat; + pid_t pid; + + /* + * Find the appropriate file pointer and remove it from the list. + */ + THREAD_LOCK(); + for (last = NULL, cur = pidlist; cur; last = cur, cur = cur->next) + if (cur->fp == iop) + break; + if (cur == NULL) { + THREAD_UNLOCK(); + return (-1); + } + if (last == NULL) + pidlist = cur->next; + else + last->next = cur->next; + THREAD_UNLOCK(); + + (void)fclose(iop); + + do { + pid = _wait4(cur->pid, &pstat, 0, (struct rusage *)0); + } while (pid == -1 && errno == EINTR); + + free(cur); + + return (pid == -1 ? -1 : pstat); +} |
