libbb: shrink lineedit_read_key()

function                                             old     new   delta
lineedit_read_key                                    237     231      -6

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

7 files changed, 25 insertions, 16 deletions

diff --git a/archival/libarchive/decompress_bunzip2.c b/archival/libarchive/decompress_bunzip2.c
index 42e2b4f88..4a2b668aa 100644
--- a/archival/libarchive/decompress_bunzip2.c
+++ b/archival/libarchive/decompress_bunzip2.c
@@ -654,7 +654,7 @@ static int read_bunzip(bunzip_data *bd, char *outbuf, int len)
                                 /* Subtract the 1 copy we'd output anyway to get extras */
                                 --bd->writeCopies;
                         }
-                } /* for(;;) */
+                } /* for (;;) */
 
                 /* Decompression of this input block completed successfully */
                 bd->writeCRC = CRC = ~CRC;
diff --git a/coreutils/head.c b/coreutils/head.c
index 9586f869f..c7537a20e 100644
--- a/coreutils/head.c
+++ b/coreutils/head.c
@@ -76,7 +76,7 @@ print_except_N_last_bytes(FILE *fp, unsigned count)
 {
         unsigned char *circle = xmalloc(++count);
         unsigned head = 0;
-        for(;;) {
+        for (;;) {
                 int c;
                 c = getc(fp);
                 if (c == EOF)
@@ -105,7 +105,7 @@ print_except_N_last_lines(FILE *fp, unsigned count)
 {
         char **circle = xzalloc((++count) * sizeof(circle[0]));
         unsigned head = 0;
-        for(;;) {
+        for (;;) {
                 char *c;
                 c = xmalloc_fgets(fp);
                 if (!c)
@@ -127,7 +127,7 @@ print_except_N_last_lines(FILE *fp, unsigned count)
         }
  ret:
         head = 0;
-        for(;;) {
+        for (;;) {
                 free(circle[head++]);
                 if (head == count)
                         break;
diff --git a/editors/patch.c b/editors/patch.c
index 110176630..aebb5073e 100644
--- a/editors/patch.c
+++ b/editors/patch.c
@@ -418,7 +418,7 @@ int patch_main(int argc UNUSED_PARAM, char **argv)
         }
 
         // Loop through the lines in the patch
-        for(;;) {
+        for (;;) {
                 char *patchline;
 
                 patchline = xmalloc_fgetline(stdin);
diff --git a/editors/patch_toybox.c b/editors/patch_toybox.c
index aebab8132..69a508b2e 100644
--- a/editors/patch_toybox.c
+++ b/editors/patch_toybox.c
@@ -441,7 +441,7 @@ int patch_main(int argc UNUSED_PARAM, char **argv)
         TT.filein = TT.fileout = -1;
 
         // Loop through the lines in the patch
-        for(;;) {
+        for (;;) {
                 char *patchline;
 
                 patchline = get_line(TT.filepatch);
diff --git a/include/libbb.h b/include/libbb.h
index b45ce91c5..8e3b7ae8e 100644
--- a/include/libbb.h
+++ b/include/libbb.h
@@ -1900,6 +1900,8 @@ enum {
  * (unless fd is in non-blocking mode),
  * subsequent reads will time out after a few milliseconds.
  * Return of -1 means EOF or error (errno == 0 on EOF).
+ * Nonzero errno is not preserved across the call:
+ * if there was no error, errno will be cleared to 0.
  * buffer[0] is used as a counter of buffered chars and must be 0
  * on first call.
  * timeout:
diff --git a/libbb/lineedit.c b/libbb/lineedit.c
index f76afd37d..82624757e 100644
--- a/libbb/lineedit.c
+++ b/libbb/lineedit.c
@@ -2155,7 +2155,7 @@ static int lineedit_read_key(char *read_key_buffer, int timeout)
 #endif
 
         fflush_all();
-        while (1) {
+        for (;;) {
                 /* Wait for input. TIMEOUT = -1 makes read_key wait even
                  * on nonblocking stdin, TIMEOUT = 50 makes sure we won't
                  * insist on full MB_CUR_MAX buffer to declare input like
@@ -2167,24 +2167,30 @@ static int lineedit_read_key(char *read_key_buffer, int timeout)
                  *
                  * Note: read_key sets errno to 0 on success.
                  */
-                do {
+                for (;;) {
                         if ((state->flags & LI_INTERRUPTIBLE) && bb_got_signal) {
                                 errno = EINTR;
                                 return -1;
                         }
 //FIXME: still races here with signals, but small window to poll() inside read_key
                         IF_FEATURE_EDITING_WINCH(S.ok_to_redraw = 1;)
+                        /* errno = 0; - read_key does this itself */
                         ic = read_key(STDIN_FILENO, read_key_buffer, timeout);
                         IF_FEATURE_EDITING_WINCH(S.ok_to_redraw = 0;)
-                } while (!(state->flags & LI_INTERRUPTIBLE) && errno == EINTR);
+                        if (errno != EINTR)
+                                break;
+                        if (state->flags & LI_INTERRUPTIBLE) {
+                                /* LI_INTERRUPTIBLE bails out on EINTR,
+                                 * but nothing really guarantees that bb_got_signal
+                                 * is nonzero. Follow the least surprise principle:
+                                 */
+                                if (bb_got_signal == 0)
+                                        bb_got_signal = 255;
+                                goto ret;
+                        }
+                }
 
                 if (errno) {
-                        /* LI_INTERRUPTIBLE can bail out with EINTR here,
-                         * but nothing really guarantees that bb_got_signal
-                         * is nonzero. Follow the least surprise principle:
-                         */
-                        if (errno == EINTR && bb_got_signal == 0)
-                                bb_got_signal = 255; /* something nonzero */
 #if ENABLE_UNICODE_SUPPORT
                         if (errno == EAGAIN && unicode_idx != 0)
                                 goto pushback;
@@ -2251,7 +2257,7 @@ static int lineedit_read_key(char *read_key_buffer, int timeout)
 #endif
                 break;
         }
-
+ ret:
         return ic;
 }
 
diff --git a/libbb/read_key.c b/libbb/read_key.c
index 829ae215c..cf8ed411e 100644
--- a/libbb/read_key.c
+++ b/libbb/read_key.c
@@ -291,6 +291,7 @@ int64_t FAST_FUNC safe_read_key(int fd, char *buffer, int timeout)
 {
         int64_t r;
         do {
+                /* errno = 0; - read_key does this itself */
                 r = read_key(fd, buffer, timeout);
         } while (errno == EINTR);
         return r;