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#include "exec.h"
#if HAVE_STDBOOL_H
#include <stdbool.h>
#endif
#include "fs.h"
#include "../log.h"
#include <errno.h>
#include <limits.h>
#if HAVE_LINUX_LIMITS_H
#include <linux/limits.h>
#endif
#include <unistd.h>
static int max_fd() {
int fd_max = 0;
#ifdef NR_OPEN /* from <linux/limits.h> */
fd_max = NR_OPEN;
if (0 < fd_max) return fd_max;
#endif
#ifdef _SC_OPEN_MAX /* from <unistd.h> */
fd_max = sysconf(_SC_OPEN_MAX);
if (0 < fd_max) return fd_max;
#endif
#ifdef _POSIX_OPEN_MAX /* from <limits.h> */
fd_max = _POSIX_OPEN_MAX;
if (0 < fd_max) return fd_max;
#endif
return 256; /* random guess falllback value */
}
pid_t exec_subcmd(
char *const argv[], int stdin, int stdout, int stderr,
bool close_fds, const char *cwd, envp_t *const envp) {
pid_t pid = fork();
if (0 != pid) {
/* parent */
return pid;
}
/* child */
/* replace "standard" FDs */
if (-1 == dup2(stdin, 0)) {
sk_error("failed to replace stdin for subcmd: %s", strerror(errno));
return -1;
}
if (-1 == dup2(stdout, 1)) {
sk_error("failed to replace stdout for subcmd: %s", strerror(errno));
return -1;
}
if (-1 == dup2(stderr, 2)) {
sk_error("failed to replace stderr for subcmd: %s", strerror(errno));
return -1;
}
if (close_fds) {
/* close all "non-standard" FDs */
for (int i = 3, m = max_fd(); i < m; ++i) {
(void)close(i);
}
}
/* chdir */
if (NULL != cwd) {
if (-1 == chdir(cwd)) {
sk_error(
"error in subcommand execution: chdir(%s) failed: %s",
cwd, strerror(errno));
exit(-1);
}
}
char executable[PATH_MAX+1];
which(argv[0], executable, envp_get(envp, "PATH"));
if (is_empty_string(executable)) {
/* no such command found */
/* TODO: handle error */
exit(-1);
}
if (NULL != envp) {
execve(executable, argv, *envp);
} else {
execv(executable, argv);
}
exit(-1);
}
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