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#include "process.h"
#include <fcntl.h>
#include <sys/wait.h>
#include <signal.h>
struct Process {
pid_t pid;
int stdout_pipe;
int stdin_pipe;
char error[64];
};
bool process_run_ex(Process *proc, const char *command, const ProcessSettings *settings) {
memset(proc, 0, sizeof *proc);
int stdin_pipe[2] = {0}, stdout_pipe[2] = {0};
if (pipe(stdin_pipe) != 0) {
strbuf_printf(proc->error, "%s", strerror(errno));
return false;
}
if (pipe(stdout_pipe) != 0) {
strbuf_printf(proc->error, "%s", strerror(errno));
close(stdin_pipe[0]);
close(stdin_pipe[1]);
return false;
}
bool success = false;
pid_t pid = fork();
if (pid == 0) {
// child process
// put child in its own group. it will be in this group with all of its descendents,
// so by killing everything in the group, we kill all the descendents of this process.
// if we didn't do this, we would just be killing the sh process in process_kill.
setpgid(0, 0);
// pipe stuff
dup2(stdout_pipe[1], STDOUT_FILENO);
dup2(stdout_pipe[1], STDERR_FILENO);
dup2(stdin_pipe[0], STDIN_FILENO);
// don't need these file descriptors anymore
close(stdout_pipe[0]);
close(stdout_pipe[1]);
close(stdin_pipe[0]);
close(stdin_pipe[1]);
char *program = "/bin/sh";
char *argv[] = {program, "-c", (char *)command, NULL};
if (execv(program, argv) == -1) {
dprintf(STDERR_FILENO, "%s: %s\n", program, strerror(errno));
exit(127);
}
} else if (pid > 0) {
// parent process
// we're reading from (the child's) stdout and writing to stdin,
// so we don't need the write end of the stdout pipe or the
// read end of the stdin pipe.
close(stdout_pipe[1]);
close(stdin_pipe[0]);
// set pipes to non-blocking
if (!settings->stdout_blocking)
fcntl(stdout_pipe[0], F_SETFL, fcntl(stdout_pipe[0], F_GETFL) | O_NONBLOCK);
if (!settings->stdin_blocking)
fcntl(stdin_pipe[1], F_SETFL, fcntl(stdin_pipe[1], F_GETFL) | O_NONBLOCK);
proc->pid = pid;
proc->stdout_pipe = stdout_pipe[0];
proc->stdin_pipe = stdin_pipe[1];
success = true;
}
return success;
}
bool process_run(Process *proc, char const *command) {
const ProcessSettings settings = {0};
return process_run_ex(proc, command, &settings);
}
char const *process_geterr(Process *p) {
return *p->error ? p->error : NULL;
}
long long process_write(Process *proc, const char *data, size_t size) {
assert(proc->stdin_pipe); // check that process hasn't been killed
ssize_t bytes_written = write(proc->stdin_pipe, data, size);
if (bytes_written >= 0) {
return (long long)bytes_written;
} else if (errno == EAGAIN) {
return 0;
} else {
strbuf_printf(proc->error, "%s", strerror(errno));
return -2;
}
}
long long process_read(Process *proc, char *data, size_t size) {
assert(proc->stdout_pipe);
ssize_t bytes_read = read(proc->stdout_pipe, data, size);
if (bytes_read >= 0) {
return (long long)bytes_read;
} else if (errno == EAGAIN) {
return -1;
} else {
strbuf_printf(proc->error, "%s", strerror(errno));
return -2;
}
}
static void process_close_pipes(Process *proc) {
close(proc->stdout_pipe);
close(proc->stdin_pipe);
proc->stdout_pipe = 0;
proc->stdin_pipe = 0;
}
void process_kill(Process *proc) {
kill(-proc->pid, SIGKILL); // kill everything in process group
// get rid of zombie process
waitpid(proc->pid, NULL, 0);
proc->pid = 0;
process_close_pipes(proc);
}
int process_check_status(Process *proc, char *message, size_t message_size) {
int wait_status = 0;
int ret = waitpid(proc->pid, &wait_status, WNOHANG);
if (ret == 0) {
// process still running
return 0;
} else if (ret > 0) {
if (WIFEXITED(wait_status)) {
process_close_pipes(proc);
int code = WEXITSTATUS(wait_status);
if (code == 0) {
str_printf(message, message_size, "exited successfully");
return +1;
} else {
str_printf(message, message_size, "exited with code %d", code);
return -1;
}
} else if (WIFSIGNALED(wait_status)) {
process_close_pipes(proc);
str_printf(message, message_size, "terminated by signal %d", WTERMSIG(wait_status));
return -1;
}
return 0;
} else {
// this process is gone or something?
process_close_pipes(proc);
str_printf(message, message_size, "process ended unexpectedly");
return -1;
}
}
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