c程序,带有管道,以执行“EXECUTE”;ps aux“grep firefox”tee processs.txt“;
这是我的第一个问题。希望不会是达姆。我在编写一个生成“ps aux | grep firefox | tee processs.txt”的程序时遇到了问题。我成功地使用了1个类似于“ps aux | grep firefox”的管道,但当我尝试推广时,我遇到了问题。我的意图是使用管道来理解它们。我知道这是可能的开放。任何暗示都很好c程序,带有管道,以执行“EXECUTE”;ps aux“grep firefox”tee processs.txt“;,c,linux,pipe,C,Linux,Pipe,这是我的第一个问题。希望不会是达姆。我在编写一个生成“ps aux | grep firefox | tee processs.txt”的程序时遇到了问题。我成功地使用了1个类似于“ps aux | grep firefox”的管道,但当我尝试推广时,我遇到了问题。我的意图是使用管道来理解它们。我知道这是可能的开放。任何暗示都很好 #include <stdio.h> #include <stdlib.h> #include <unistd.h> #inclu
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/wait.h>
#include <sys/types.h>
int main(void)
{
char *** args = NULL;
pid_t fork_id = -1;
int ** pipes = NULL;
int status = 0;
int i = 0, k = 0;
int check = 0;
args = calloc(3, sizeof(char **));
args [0] = calloc(3, sizeof(char *));
args [1] = calloc(3, sizeof(char *));
args [2] = calloc(3, sizeof(char *));
args[0][0]= "ps";
args[0][1]="aux";
args[0][2]= NULL;
args[1][0]= "grep";
args[1][1]= "firefox";
args[1][2]= NULL;
args[2][0]= "tee";
args[2][1]= "processes.txt";
args[2][2]= NULL;
pipes=calloc(2,sizeof(int *));
for(i=0;i<2;++i){
pipes[i]=calloc(2,sizeof(int));
}
for(i=0;i<2;++i){
pipes[i]=calloc(2,sizeof(int));
check=pipe(pipes[i]);
if(check<0){
perror("pipe");
exit(EXIT_FAILURE);
}
}
for(i=0;i<3;++i){
if ((fork_id = fork()) < 0) {
perror("fork()");
exit(1);
}
if ((i ==0)&& (fork_id == 0)){
close(pipes[i][0]);
close(1);
dup(pipes[i][1]);
close(pipes[i][1]);
execvp(args[i][0], args[0]);
} else if ((i!= 0)&&(i != 2) && (fork_id == 0)){
close(0);
dup(pipes[i][0]);
close(pipes[i][0]);
close(1);
dup(pipes[i][1]);
close(pipes[i][1]);
execvp(args[i][0], args[i]);
} else if ((i==2)&&(fork_id != 0)){
close(pipes[i-1][1]);
close(0);
dup(pipes[i-1][0]);
close(pipes[i-1][0]);
execvp(args[i][0], args[i]);
}
wait(&status);
}
for(i=0;i<2;++i){
for(k=0;k<2;++k){
check=close(pipes[i][k]);
if(check<0){
perror("close pipe");
exit(EXIT_FAILURE);
}
}
}
return(0);
}
#包括
#包括
#包括
#包括
#包括
#包括
内部主(空)
{
字符***args=NULL;
pid\u t fork\u id=-1;
int**pipes=NULL;
int status=0;
int i=0,k=0;
整数检查=0;
args=calloc(3,sizeof(char**));
args[0]=calloc(3,sizeof(char*);
args[1]=calloc(3,sizeof(char*);
args[2]=calloc(3,sizeof(char*);
args[0][0]=“ps”;
args[0][1]=“辅助”;
args[0][2]=NULL;
args[1][0]=“grep”;
args[1][1]=“firefox”;
args[1][2]=NULL;
args[2][0]=“T”;
args[2][1]=“processs.txt”;
args[2][2]=NULL;
管道=calloc(2,尺寸f(int*);
对于(i=0;iPopen),您可能会感兴趣
FILE *p = popen("ps aux | grep firefox | tee processes.txt", "r");
这可能就是您想要的-不需要所有这些执行官、分叉和管道:
#include <stdio.h>
#include <stdlib.h>
int main() {
FILE *p;
int status;
char line[1024];
p = popen("ps aux | grep firefox | tee processes.txt", "r");
if (!p) {
fprintf(stderr, "Error.");
exit(1);
}
while (fgets(line, sizeof(line) - 1, p)) {
puts(line);
}
pclose(p);
}
#包括
#包括
int main(){
文件*p;
智力状态;
字符行[1024];
p=popen(“ps aux | grep firefox | tee processs.txt”,“r”);
如果(!p){
fprintf(标准“错误”);
出口(1);
}
while(fgets(line,sizeof(line)-1,p)){
放(线);
}
pclose(p);
}
可接受的解决方案仅适用于此管道:
/*
** How to create a pipeline of N processes?
** SO 18582446: ps aux | grep firefox | tee processes.txt
** Adaptation of accepted answer to:
** SO 13636252 C Minishell adding pipelines
*/
/* stderr.h */
#ifndef STDERR_H_INCLUDED
#define STDERR_H_INCLUDED
static void err_setarg0(const char *argv0);
static void err_sysexit(char const *fmt, ...);
static void err_syswarn(char const *fmt, ...);
#endif /* STDERR_H_INCLUDED */
/* pipeline.c */
#include <assert.h>
#include <stdio.h>
#include <string.h>
#include <sys/wait.h>
#include <unistd.h>
/*#include "stderr.h"*/
typedef int Pipe[2];
/* Now: ps aux | grep firefox | tee processes.txt */
/* Was: who | awk '{print $1}' | sort | uniq -c | sort -n */
static char *cmd0[] = { "ps", "aux", 0 };
static char *cmd1[] = { "grep", "firefox", 0 };
static char *cmd2[] = { "tee", "processes.txt", 0 };
static char **cmds[] = { cmd0, cmd1, cmd2, };
static int ncmds = sizeof(cmds) / sizeof(cmds[0]);
/* exec_nth_command() and exec_pipe_command() are mutually recursive */
static void exec_pipe_command(int ncmds, char ***cmds, Pipe output);
/* With the standard output plumbing sorted, execute Nth command */
static void exec_nth_command(int ncmds, char ***cmds)
{
assert(ncmds >= 1);
if (ncmds > 1)
{
pid_t pid;
Pipe input;
if (pipe(input) != 0)
err_sysexit("Failed to create pipe");
if ((pid = fork()) < 0)
err_sysexit("Failed to fork");
if (pid == 0)
{
/* Child */
exec_pipe_command(ncmds-1, cmds, input);
}
/* Fix standard input to read end of pipe */
dup2(input[0], 0);
close(input[0]);
close(input[1]);
}
execvp(cmds[ncmds-1][0], cmds[ncmds-1]);
err_sysexit("Failed to exec %s", cmds[ncmds-1][0]);
/*NOTREACHED*/
}
/* Given pipe, plumb it to standard output, then execute Nth command */
static void exec_pipe_command(int ncmds, char ***cmds, Pipe output)
{
assert(ncmds >= 1);
/* Fix stdout to write end of pipe */
dup2(output[1], 1);
close(output[0]);
close(output[1]);
exec_nth_command(ncmds, cmds);
}
/* Execute the N commands in the pipeline */
static void exec_pipeline(int ncmds, char ***cmds)
{
assert(ncmds >= 1);
pid_t pid;
if ((pid = fork()) < 0)
err_syswarn("Failed to fork");
if (pid != 0)
return;
exec_nth_command(ncmds, cmds);
}
/* Collect dead children until there are none left */
static void corpse_collector(void)
{
pid_t parent = getpid();
pid_t corpse;
int status;
while ((corpse = waitpid(0, &status, 0)) != -1)
{
fprintf(stderr, "%d: child %d status 0x%.4X\n",
(int)parent, (int)corpse, status);
}
}
static void exec_arguments(int argc, char **argv)
{
/* Split the command line into sequences of arguments */
/* Break at pipe symbols as arguments on their own */
char **cmdv[argc/2]; // Way too many
char *args[argc+1];
int cmdn = 0;
int argn = 0;
cmdv[cmdn++] = &args[argn];
for (int i = 1; i < argc; i++)
{
char *arg = argv[i];
if (strcmp(arg, "|") == 0)
{
if (i == 1)
err_sysexit("Syntax error: pipe before any command");
if (args[argn-1] == 0)
err_sysexit("Syntax error: two pipes with no command between");
arg = 0;
}
args[argn++] = arg;
if (arg == 0)
cmdv[cmdn++] = &args[argn];
}
if (args[argn-1] == 0)
err_sysexit("Syntax error: pipe with no command following");
args[argn] = 0;
exec_pipeline(cmdn, cmdv);
}
#include <signal.h>
typedef void (*SigHandler)(int signum);
static void sigchld_status(void)
{
const char *handling = "Handler";
SigHandler sigchld = signal(SIGCHLD, SIG_IGN);
signal(SIGCHLD, sigchld);
if (sigchld == SIG_IGN)
handling = "Ignored";
else if (sigchld == SIG_DFL)
handling = "Default";
printf("SIGCHLD set to %s\n", handling);
}
int main(int argc, char **argv)
{
err_setarg0(argv[0]);
sigchld_status();
if (argc == 1)
{
/* Run the built in pipe-line */
exec_pipeline(ncmds, cmds);
}
else
{
/* Run command line specified by user */
exec_arguments(argc, argv);
}
corpse_collector();
return(0);
}
/* stderr.c */
/*#include "stderr.h"*/
#include <stdio.h>
#include <stdarg.h>
#include <errno.h>
#include <string.h>
#include <stdlib.h>
static const char *arg0 = "<undefined>";
static void err_setarg0(const char *argv0)
{
arg0 = argv0;
}
static void err_vsyswarn(char const *fmt, va_list args)
{
int errnum = errno;
fprintf(stderr, "%s:%d: ", arg0, (int)getpid());
vfprintf(stderr, fmt, args);
if (errnum != 0)
fprintf(stderr, " (%d: %s)", errnum, strerror(errnum));
putc('\n', stderr);
}
static void err_syswarn(char const *fmt, ...)
{
va_list args;
va_start(args, fmt);
err_vsyswarn(fmt, args);
va_end(args);
}
static void err_sysexit(char const *fmt, ...)
{
va_list args;
va_start(args, fmt);
err_vsyswarn(fmt, args);
va_end(args);
exit(1);
}
/*
**如何创建N个进程的管道?
**所以18582446:ps aux | grep firefox | tee processs.txt
**将公认答案改编为:
**因此,13636252 C微型管添加管道
*/
/*标准*/
#如果不包括标准的话
#定义包含的标准
静态无效错误设置arg0(常量字符*argv0);
静态void err_sysexit(字符常量*fmt,…);
静态void err_syswarn(字符常量*fmt,…);
#endif/*包括标准件*/
/*管道c*/
#包括
#包括
#包括
#包括
#包括
/*#包括“stderr.h”*/
类型定义内部管道[2];
/*现在:ps aux | grep firefox | tee processs.txt*/
/*Was:who | awk{print$1}| sort | uniq-c | sort-n*/
静态字符*cmd0[]={“ps”,“aux”,0};
静态字符*cmd1[]={“grep”,“firefox”,0};
静态字符*cmd2[]={“tee”,“processs.txt”,0};
静态字符**cmds[]={cmd0,cmd1,cmd2,};
静态int-ncmds=sizeof(cmds)/sizeof(cmds[0]);
/*exec\u nth\u command()和exec\u pipe\u command()是相互递归的*/
静态void exec_pipe_命令(int-ncmds、char***cmds、pipe-output);
/*对标准输出管道进行排序后,执行第n个命令*/
静态void exec\u nth\u命令(int-ncmds、char***cmds)
{
断言(ncmds>=1);
如果(ncmds>1)
{
pid_t pid;
管道输入;
如果(管道(输入)!=0)
err_sysexit(“未能创建管道”);
如果((pid=fork())<0)
err_sysexit(“未能分叉”);
如果(pid==0)
{
/*孩子*/
exec_pipe_命令(ncmds-1,cmds,输入);
}
/*固定标准输入以读取管道末端*/
dup2(输入[0],0);
关闭(输入[0]);
关闭(输入[1]);
}
execvp(cmds[ncmds-1][0],cmds[ncmds-1]);
err_sysexit(“未能执行%s”,cmds[ncmds-1][0]);
/*未到达*/
}
/*给定管道,使其垂直于标准输出,然后执行第n个命令*/
静态void exec_pipe_命令(int-ncmds、char***cmds、管道输出)
{
断言(ncmds>=1);
/*将标准输出固定到管道末端*/
dup2(输出[1],1);
关闭(输出[0]);
关闭(输出[1]);
执行命令(ncmds、cmds);
}
/*在管道中执行N个命令*/
静态void exec_管道(int-ncmds、char***cmds)
{
断言(ncmds>=1);
pid_t pid;
如果((pid=fork())<0)
err_syswarn(“未能分叉”);
如果(pid!=0)
返回;
执行命令(ncmds、cmds);
}
/*收集死去的孩子,直到一个也没有留下*/
静态无效尸体收集器(无效)
{
pid_t parent=getpid();
尸体;
智力状态;
while((尸体=waitpid(0,&status,0))!=-1)
{
fprintf(stderr,“%d:子%d状态0x%.4X\n”,
(int)父母,(int)尸体,身份);
}
}
静态void exec_参数(int argc,char**argv)
{
/*将命令行拆分为参数序列*/
/*管道符号本身作为参数的打断*/
char**cmdv[argc/2];//太多了
字符*args[argc+1];
int-cmdn=0;
int argn=0;
cmdv[cmdn++]=&args[argn];
对于(int i=1;i