diff options
Diffstat (limited to 'libblkid/pager.c')
| -rw-r--r-- | libblkid/pager.c | 220 |
1 files changed, 0 insertions, 220 deletions
diff --git a/libblkid/pager.c b/libblkid/pager.c deleted file mode 100644 index 5cf8c03b5..000000000 --- a/libblkid/pager.c +++ /dev/null @@ -1,220 +0,0 @@ -/* - * Based on linux-perf/git scm - * - * Some modifications and simplifications for util-linux - * by Davidlohr Bueso <dave@xxxxxxx> - March 2012. - */ - -#include <unistd.h> -#include <stdlib.h> -#include <string.h> -#include <err.h> -#include <sys/types.h> -#include <sys/stat.h> -#include <sys/wait.h> - -#include "c.h" -#include "xalloc.h" -#include "nls.h" - -#define NULL_DEVICE "/dev/null" - -void setup_pager(void); - -static const char *pager_argv[] = { "sh", "-c", NULL, NULL }; - -struct child_process { - const char **argv; - pid_t pid; - int in; - int out; - int err; - unsigned no_stdin:1; - void (*preexec_cb)(void); -}; -static struct child_process pager_process; - -static inline void close_pair(int fd[2]) -{ - close(fd[0]); - close(fd[1]); -} - -static inline void dup_devnull(int to) -{ - int fd = open(NULL_DEVICE, O_RDWR); - - if (fd < 0) - err(EXIT_FAILURE, _("cannot open %s"), NULL_DEVICE); - dup2(fd, to); - close(fd); -} - -static int start_command(struct child_process *cmd) -{ - int need_in; - int fdin[2]; - - /* - * In case of errors we must keep the promise to close FDs - * that have been passed in via ->in and ->out. - */ - need_in = !cmd->no_stdin && cmd->in < 0; - if (need_in) { - if (pipe(fdin) < 0) { - if (cmd->out > 0) - close(cmd->out); - return -1; - } - cmd->in = fdin[1]; - } - - fflush(NULL); - cmd->pid = fork(); - if (!cmd->pid) { - if (need_in) { - dup2(fdin[0], 0); - close_pair(fdin); - } else if (cmd->in > 0) { - dup2(cmd->in, 0); - close(cmd->in); - } - - cmd->preexec_cb(); - execvp(cmd->argv[0], (char *const*) cmd->argv); - exit(127); /* cmd not found */ - } - - if (cmd->pid < 0) { - if (need_in) - close_pair(fdin); - else if (cmd->in) - close(cmd->in); - return -1; - } - - if (need_in) - close(fdin[0]); - else if (cmd->in) - close(cmd->in); - return 0; -} - -static int wait_or_whine(pid_t pid) -{ - for (;;) { - int status, code; - pid_t waiting = waitpid(pid, &status, 0); - - if (waiting < 0) { - if (errno == EINTR) - continue; - err(EXIT_FAILURE, _("waitpid failed (%s)"), strerror(errno)); - } - if (waiting != pid) - return -1; - if (WIFSIGNALED(status)) - return -1; - - if (!WIFEXITED(status)) - return -1; - code = WEXITSTATUS(status); - switch (code) { - case 127: - return -1; - case 0: - return 0; - default: - return -1; - } - } -} - -static int finish_command(struct child_process *cmd) -{ - return wait_or_whine(cmd->pid); -} - -static void pager_preexec(void) -{ - /* - * Work around bug in "less" by not starting it until we - * have real input - */ - fd_set in; - - FD_ZERO(&in); - FD_SET(0, &in); - select(1, &in, NULL, &in, NULL); - - setenv("LESS", "FRSX", 0); -} - -static void wait_for_pager(void) -{ - fflush(stdout); - fflush(stderr); - /* signal EOF to pager */ - close(1); - close(2); - finish_command(&pager_process); -} - -static void wait_for_pager_signal(int signo) -{ - wait_for_pager(); - raise(signo); -} - -void setup_pager(void) -{ - const char *pager = getenv("PAGER"); - - if (!isatty(1)) - return; - - if (!pager) - pager = "less"; - else if (!*pager || !strcmp(pager, "cat")) - return; - - /* spawn the pager */ - pager_argv[2] = pager; - pager_process.argv = pager_argv; - pager_process.in = -1; - pager_process.preexec_cb = pager_preexec; - - if (start_command(&pager_process)) - return; - - /* original process continues, but writes to the pipe */ - dup2(pager_process.in, 1); - if (isatty(2)) - dup2(pager_process.in, 2); - close(pager_process.in); - - /* this makes sure that the parent terminates after the pager */ - signal(SIGINT, wait_for_pager_signal); - signal(SIGHUP, wait_for_pager_signal); - signal(SIGTERM, wait_for_pager_signal); - signal(SIGQUIT, wait_for_pager_signal); - signal(SIGPIPE, wait_for_pager_signal); - - atexit(wait_for_pager); -} - -#ifdef TEST_PROGRAM - -#define MAX 255 - -int main(int argc __attribute__ ((__unused__)), - char *argv[] __attribute__ ((__unused__))) -{ - int i; - - setup_pager(); - for (i = 0; i < MAX; i++) - printf("%d\n", i); - return EXIT_SUCCESS; -} -#endif /* TEST_PROGRAM */ |