Start 1.33.0 development cycle

[oweals/busybox.git] / libbb / read.c

diff --git a/libbb/read.c b/libbb/read.c
index 861828da19e316f297046a9835562ccfa480b220..a342506a8e738699f0f231c854e8b2f2be365162 100644 (file)
--- a/libbb/read.c
+++ b/libbb/read.c
@@ -4,18 +4,25 @@
  *
  * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
  *
- * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
+ * Licensed under GPLv2 or later, see file LICENSE in this source tree.
  */
-
 #include "libbb.h"
 
-ssize_t safe_read(int fd, void *buf, size_t count)
+ssize_t FAST_FUNC safe_read(int fd, void *buf, size_t count)
 {
        ssize_t n;
 
-       do {
+       for (;;) {
                n = read(fd, buf, count);
-       } while (n < 0 && errno == EINTR);
+               if (n >= 0 || errno != EINTR)
+                       break;
+               /* Some callers set errno=0, are upset when they see EINTR.
+                * Returning EINTR is wrong since we retry read(),
+                * the "error" was transient.
+                */
+               errno = 0;
+               /* repeat the read() */
+       }
 
        return n;
 }
@@ -26,7 +33,7 @@ ssize_t safe_read(int fd, void *buf, size_t count)
  * Returns the amount read, or -1 on an error.
  * A short read is returned on an end of file.
  */
-ssize_t full_read(int fd, void *buf, size_t len)
+ssize_t FAST_FUNC full_read(int fd, void *buf, size_t len)
 {
        ssize_t cc;
        ssize_t total;
@@ -36,12 +43,16 @@ ssize_t full_read(int fd, void *buf, size_t len)
        while (len) {
                cc = safe_read(fd, buf, len);
 
-               if (cc < 0)
-                       return cc;      /* read() returns -1 on failure. */
-
+               if (cc < 0) {
+                       if (total) {
+                               /* we already have some! */
+                               /* user can do another read to know the error code */
+                               return total;
+                       }
+                       return cc; /* read() returns -1 on failure. */
+               }
                if (cc == 0)
                        break;
-
                buf = ((char *)buf) + cc;
                total += cc;
                len -= cc;
@@ -50,88 +61,20 @@ ssize_t full_read(int fd, void *buf, size_t len)
        return total;
 }
 
-// Die with an error message if we can't read the entire buffer.
-void xread(int fd, void *buf, size_t count)
-{
-       if (count) {
-               ssize_t size = full_read(fd, buf, count);
-               if (size != count)
-                       bb_error_msg_and_die("short read");
-       }
-}
-
-// Die with an error message if we can't read one character.
-unsigned char xread_char(int fd)
-{
-       char tmp;
-
-       xread(fd, &tmp, 1);
-
-       return tmp;
-}
-
-// Read one line a-la fgets. Works only on seekable streams
-char *reads(int fd, char *buffer, size_t size)
-{
-       char *p;
-
-       if (size < 2)
-               return NULL;
-       size = full_read(fd, buffer, size-1);
-       if ((ssize_t)size <= 0)
-               return NULL;
-
-       buffer[size] = '\0';
-       p = strchr(buffer, '\n');
-       if (p) {
-               off_t offset;
-               *p++ = '\0';
-               // avoid incorrect (unsigned) widening
-               offset = (off_t)(p-buffer) - (off_t)size;
-               // set fd position right after '\n'
-               if (offset && lseek(fd, offset, SEEK_CUR) == (off_t)-1)
-                       return NULL;
-       }
-       return buffer;
-}
-
-ssize_t read_close(int fd, void *buf, size_t size)
+ssize_t FAST_FUNC read_close(int fd, void *buf, size_t size)
 {
-       int e;
+       /*int e;*/
        size = full_read(fd, buf, size);
-       e = errno;
+       /*e = errno;*/
        close(fd);
-       errno = e;
+       /*errno = e;*/
        return size;
 }
 
-ssize_t open_read_close(const char *filename, void *buf, size_t size)
+ssize_t FAST_FUNC open_read_close(const char *filename, void *buf, size_t size)
 {
        int fd = open(filename, O_RDONLY);
        if (fd < 0)
                return fd;
        return read_close(fd, buf, size);
 }
-
-void *xmalloc_open_read_close(const char *filename, size_t *sizep)
-{
-       char *buf;
-       size_t size = sizep ? *sizep : INT_MAX;
-       int fd = xopen(filename, O_RDONLY);
-       /* /proc/N/stat files report len 0 here */
-       /* In order to make such files readable, we add small const */
-       off_t len = xlseek(fd, 0, SEEK_END) + 256;
-       xlseek(fd, 0, SEEK_SET);
-
-       if (len > size)
-               bb_error_msg_and_die("file '%s' is too big", filename);
-       size = len;
-       buf = xmalloc(size + 1);
-       size = read_close(fd, buf, size);
-       if ((ssize_t)size < 0)
-               bb_perror_msg_and_die("'%s'", filename);
-       xrealloc(buf, size + 1);
-       buf[size] = '\0';
-       if (sizep) *sizep = size;
-       return buf;
-}