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#include <stdexcept>
#include <cstring>
#include <errno.h>
#include <unistd.h>
#include <signal.h>
#include <sys/wait.h>
#include "command.h"
std::pair<int, std::string> readCommand(const std::vector<std::string> &args) {
int pipefd[2];
if (pipe(pipefd) < 0) {
throw std::runtime_error("readCommand: pipe: " + std::string{strerror(errno)});
}
pid_t pid = fork();
if (pid < 0) {
throw std::runtime_error("readCommand: fork: " + std::string{strerror(errno)});
}
if (pid == 0) {
close(STDOUT_FILENO);
dup2(pipefd[1], STDOUT_FILENO);
close(pipefd[0]);
close(pipefd[1]);
std::vector<char*> argv(args.size() + 1);
for (size_t i = 0; i < args.size(); i++) {
argv[i] = new char[args[i].size() + 1];
memcpy(argv[i], args[i].data(), args[i].size() + 1);
}
argv[args.size()] = nullptr;
execvp(argv[0], argv.data());
perror("execvp");
exit(255);
}
close(pipefd[1]);
std::string output;
while (true) {
size_t base = output.size();
output.resize(base + 4096);
ssize_t nr = read(pipefd[0], output.data() + base, 4096);
if (nr < 0) {
if (errno == EINTR) {
output.resize(base);
continue;
}
kill(pid, SIGTERM);
throw std::runtime_error("readCommand: read: " + std::string{strerror(errno)});
}
output.resize(base + nr);
if (nr == 0) break;
}
while (true) {
int status;
pid_t wpid = waitpid(pid, &status, 0);
if (wpid < 0) {
if (errno == EINTR) continue;
kill(pid, SIGTERM);
throw std::runtime_error("readCommand: wait: " + std::string{strerror(errno)});
}
if (WIFEXITED(status)) {
return std::make_pair(WEXITSTATUS(status), output);
}
}
}
std::string runCommand(const std::vector<std::string> &args) {
auto result = readCommand(args);
if (result.first != 0) {
std::string cmdline;
for (const std::string &a : args) cmdline += " " + a;
throw std::runtime_error(
"Command exited with exit code " + std::to_string(result.first) + ":" + cmdline
);
}
return result.second;
}
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