hush: use SA_RESTARTed signal handlers across read.

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 21 insertions, 13 deletions

diff --git a/shell/shell_common.c b/shell/shell_common.c
index a5c455c8e..bbc22ed34 100644
--- a/shell/shell_common.c
+++ b/shell/shell_common.c
@@ -159,32 +159,40 @@ shell_builtin_read(void FAST_FUNC (*setvar)(const char *name, const char *val),
         bufpos = 0;
         do {
                 char c;
+                struct pollfd pfd[1];
+                int timeout;
 
-                errno = 0;
+                if ((bufpos & 0xff) == 0)
+                        buffer = xrealloc(buffer, bufpos + 0x100);
 
+                timeout = -1;
                 if (end_ms) {
-                        int timeout;
-                        struct pollfd pfd[1];
-
-                        pfd[0].fd = fd;
-                        pfd[0].events = POLLIN;
                         timeout = end_ms - (unsigned)monotonic_ms();
-                        if (timeout <= 0 /* already late? */
-                         || poll(pfd, 1, timeout) != 1 /* no? wait... */
-                        ) { /* timed out! */
-                                err = errno;
+                        if (timeout <= 0) { /* already late? */
                                 retval = (const char *)(uintptr_t)1;
                                 goto ret;
                         }
                 }
 
-                if ((bufpos & 0xff) == 0)
-                        buffer = xrealloc(buffer, bufpos + 0x100);
-                if (nonblock_immune_read(fd, &buffer[bufpos], 1, /*loop_on_EINTR:*/ 0) != 1) {
+                /* We must poll even if timeout is -1:
+                 * we want to be interrupted if signal arrives,
+                 * regardless of SA_RESTART-ness of that signal!
+                 */
+                errno = 0;
+                pfd[0].fd = fd;
+                pfd[0].events = POLLIN;
+                if (poll(pfd, 1, timeout) != 1) {
+                        /* timed out, or EINTR */
+                        err = errno;
+                        retval = (const char *)(uintptr_t)1;
+                        goto ret;
+                }
+                if (read(fd, &buffer[bufpos], 1) != 1) {
                         err = errno;
                         retval = (const char *)(uintptr_t)1;
                         break;
                 }
+
                 c = buffer[bufpos];
                 if (c == '\0')
                         continue;