fork

Calling exec returns errno 14 (bad address) with absolute path

由 被刻印的时光 ゝ 提交于 2019-12-19 08:05:32
问题 in making a simple cgi server for a course. To do that in some point I have to make a fork/exec to launch the cgi handler, the problem is that the exec keep returning errno 14. I've tried the following code in a standalone version an it works with and without the absolute path. Here's the code: static void _process_cgi(int fd, http_context_t* ctx) { pid_t childProcess; int ret; char returnValue[1024]; log(LOG, "calling cgi", &ctx->uri[1], 0); if((childProcess = fork()) != 0) { /// /// Set the

Calling exec returns errno 14 (bad address) with absolute path

由 萝らか妹 提交于 2019-12-19 08:05:10
问题 in making a simple cgi server for a course. To do that in some point I have to make a fork/exec to launch the cgi handler, the problem is that the exec keep returning errno 14. I've tried the following code in a standalone version an it works with and without the absolute path. Here's the code: static void _process_cgi(int fd, http_context_t* ctx) { pid_t childProcess; int ret; char returnValue[1024]; log(LOG, "calling cgi", &ctx->uri[1], 0); if((childProcess = fork()) != 0) { /// /// Set the

Calling exec returns errno 14 (bad address) with absolute path

由 会有一股神秘感。 提交于 2019-12-19 08:05:06
问题 in making a simple cgi server for a course. To do that in some point I have to make a fork/exec to launch the cgi handler, the problem is that the exec keep returning errno 14. I've tried the following code in a standalone version an it works with and without the absolute path. Here's the code: static void _process_cgi(int fd, http_context_t* ctx) { pid_t childProcess; int ret; char returnValue[1024]; log(LOG, "calling cgi", &ctx->uri[1], 0); if((childProcess = fork()) != 0) { /// /// Set the

021 UNIX再学习 -- 发送信号

由 无人久伴 提交于 2019-12-19 06:05:17
一、发送信号的方式 发送信号的方式有几种： 1、由键盘触发的信号（只能发送一些比较特殊的信号） SIGINT (2)：ctrl+c 中断符 SIGQUIT (3)：ctrl+\ 退出符 SIGTSTP (20)：ctrl+z 停止符 2、由错误和异常引发的信号 SIGILL (4) 进程试图执行非法指令 SIGBUS (7) 硬件或对齐错误 SIGFPE (8) 算术异常 SIGSEGV (11) 无法内存访问 SIGPIPE (13) 向无读取进程的管道写入 SIGSTKFLT (16) 协处理器栈错误 SIGXFSZ (25) 文件资源超限 SIGPWR (30) 断电 SIGSYS (31) 进程试图执行无效系统调用 3、用专门的系统命令发送信号 kill [-信号] PIDs 若不指明具体的信号，缺省发送 SIGTERM (15) 信号。 该信号允许用户优雅地终止进程。进程可以选择捕获该信号，并在临终之前完成必要的清理和善后工作。但如果捕获了该信号，却死赖着不走，则有流氓进程之嫌。 若要指明具体信号，可以使用信号编号，也可以使用信号名称，而且信号名称中的“SIG”前缀可以省略不写。例如： kill -9 1234 kill -SIGKILL 1234 kill -KILL 1234 kill -9 -1 （终止所有进程） 接收信号的进程可以是一个、多个或 所有的（PIDs

perl: executing multiple systems processes and waiting for them to finish

由 本秂侑毒 提交于 2019-12-19 04:14:37
问题 Currently in my Perl script I make a call like the following: system(" ./long_program1 & ./long_program2 & ./long_program3 & wait "); I would like to be able to log when each of the long running commands executes while still executing them asyncronously. I know that the system call causes perl to make a fork, so is something like this possible? Could this be replaced by multiple perl fork() and exec() calls? Please help me find a better solution. 回答1: Yes, definitely. You can fork off a child

what is the proper way to pipe when making a shell in C

由 ＊爱你＆永不变心＊ 提交于 2019-12-19 03:43:16
问题 I’m attempting to create my own shell I believe i have the forking done correctly but i cannot figure out how to pipe correctly. Any help or tips would be appreciated. basically my pipes aren’t working and i have spent ages attempting to figure out how to get them to properly transmit the data between the processes. #include <stdio.h> #include <string.h> #include <stdlib.h> #include <sys/wait.h> #include <unistd.h> #include "ourhdr.h" // from Steven's book Advanced programing in the UNIX

Unix fork() system call what runs when?

由 时间秒杀一切 提交于 2019-12-19 03:14:08
问题 void child(int pid){ printf("Child PID:%d\n",pid); exit(0); } void parent(int pid){ printf("Parent PID:%d\n",pid); exit(0); } void init(){ printf("Init\n");//runs before the fork } int main(){ init();//only runs for parent i.e. runs once printf("pre fork()");// but this runs for both i.e. runs twice //why??? int pid = fork(); if(pid == 0){ child(pid); //run child process }else{ parent(pid);//run parent process } return 0; } output: Init pre fork()Parrent PID:4788 pre fork()Child PID:0 I have

Unix fork() system call what runs when?

由 ぃ、小莉子 提交于 2019-12-19 03:13:59
问题 void child(int pid){ printf("Child PID:%d\n",pid); exit(0); } void parent(int pid){ printf("Parent PID:%d\n",pid); exit(0); } void init(){ printf("Init\n");//runs before the fork } int main(){ init();//only runs for parent i.e. runs once printf("pre fork()");// but this runs for both i.e. runs twice //why??? int pid = fork(); if(pid == 0){ child(pid); //run child process }else{ parent(pid);//run parent process } return 0; } output: Init pre fork()Parrent PID:4788 pre fork()Child PID:0 I have

C static variables and linux fork

由 …衆ロ難τιáo~ 提交于 2019-12-19 00:42:38
问题 Hi I created a server program that forks a new process after its accepts a socket connection. There are several statically allocated global variables defined in the program. My question is are these static buffers allocated twice after the fork? Or does the fork only duplicate address space on the heap and the call stack? 回答1: The entire address space is duplicated, including all global variables and the program text. 回答2: The whole address space is "duplicated" during fork(2) . It's often

difference between exit and return after vfork() call

由 浪尽此生 提交于 2019-12-18 17:31:01
问题 I have a program with undefined behavior ( vfork() is used inappropriately ): #include <stdio.h> #include <unistd.h> #include <errno.h> int main ( int argc, char *argv[] ) { pid_t pid; printf("___________befor fork______________.\n"); if((pid=vfork()) < 0) perror("fork"); else if(pid > 0) printf("parent\n"); else printf("child\n"); printf("pid: %d, ppid: %d\n", getpid(), getppid()); //exit(0); return 0; } If I use exit(0) function instead return - output is: ___________befor fork_____________
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