commit 1a40e1af6901ce298fd535e83aab280c006e5b09
parent c16d905214842970bda55ab3fabac6a5a3d59af4
Author: Stephen Gregoratto <dev@sgregoratto.me>
Date: Tue, 29 Oct 2019 15:55:32 +1100
add pledge(2), simplify code
- The READ/WRITE_END preprocessor variables are replaced in favor of
global enums.
- lines is a unsigned 32-bit int because why not.
- Drop the -R flag for less as there's no colour output.
- Open PIPE_WRITE as a FILE * instead of making it STDIN_FILENO.
Saves us from calling dup2(2), close(2) and flushing the buffer.
- Liberal use of pledge(2).
Diffstat:
| M | pager.c | | | 64 | +++++++++++++++++++++++++++++++++++++++------------------------- |
1 file changed, 39 insertions(+), 25 deletions(-)
diff --git a/pager.c b/pager.c
@@ -12,25 +12,30 @@
#include <limits.h>
#include <stdint.h>
-#define READ_END 0
-#define WRITE_END 1
+enum {
+ PIPE_READ,
+ PIPE_WRITE,
+};
int
main(int argc, char **argv)
{
int fildes[2];
- int exec_status;
- uint32_t lines = 1024;
+ FILE *fpipew = NULL;
pid_t child;
+ uint32_t lines = 1024;
const char *errstr;
/*
- * F -> quit-if-one-screen
- * R -> preserve color formatting
- * X -> don't send some special instructions eg. to clear
- * terminal screen before starting
+ * F: quit if one screen
+ * X: don't send some special instructions
+ * (e.g. clearing the terminal before starting).
*/
- char *less_argv[] = { "less", "-FRX", NULL};
+ char *less_argv[] = { "less", "-FX", NULL };
+#if HAVE_PLEDGE
+ if (pledge("stdio proc exec", NULL) == -1)
+ err(1, "pledge");
+#endif
if (argc > 2) {
warnx("too many arguments: %s", argv[2]);
goto usage;
@@ -47,33 +52,42 @@ main(int argc, char **argv)
case -1:
err(1, "fork");
case 0:
+#if HAVE_PLEDGE
+ if (pledge("stdio exec", NULL) == -1)
+ err(1, "pledge");
+#endif
/* Pager process doesn't write to pipe */
- if (close(fildes[WRITE_END]) == -1)
+ if (close(fildes[PIPE_WRITE]) == -1)
err(1, "close");
- /* Make READ_END of pipe pager's STDIN */
- if (dup2(fildes[READ_END], STDIN_FILENO) == -1)
+ /* Make PIPE_READ of pipe pager's STDIN */
+ if (dup2(fildes[PIPE_READ], STDIN_FILENO) == -1)
err(1, "dup2");
-
- exec_status = execvp(less_argv[0], less_argv);
- err(1, "execvp returned %d", exec_status);
+#if HAVE_PLEDGE
+ if (pledge("exec", NULL) == -1)
+ err(1, "pledge");
+#endif
+ execvp(less_argv[0], less_argv);
+ err(1, "execvp");
break;
default:
- /* stdout is now fildes[WRITE_END] */
- if (dup2(fildes[WRITE_END], STDOUT_FILENO) == -1)
- err(1, "dup2");
- /* parent doesn't read from pipe */
- if (close(fildes[READ_END]) == -1)
+#if HAVE_PLEDGE
+ if (pledge("stdio", NULL) == -1)
+ err(1, "pledge");
+#endif
+ if ((fpipew = fdopen(fildes[PIPE_WRITE], "w")) == NULL)
+ err(1, "fdopen");
+ /* Parent doesn't read from pipe */
+ if (close(fildes[PIPE_READ]) == -1)
err(1, "close");
for (uint32_t i = 0; i <= lines; i++)
- printf("%04d\n", i);
+ fprintf(fpipew, "%04d\n", i);
- /* Signal EOF to the pager process. fclose closes STDOUT_FILENO */
- if (fclose(stdout) == EOF)
+ /* Flush the buffer and signal EOF to the pager process. */
+ if (fclose(fpipew) == EOF)
err(1, "fclose");
- if (close(fildes[WRITE_END]) == -1)
- err(1, "close");
+ /* Pass a dummy status since we don't set behavior */
if (waitpid(child, &(pid_t){0}, 0) == -1)
err(1, "waitpid");
break;