libbb: prevent xmalloc_open_read_close from dying on seek failure

start_stop_daemon: use open_read_close instead of xmalloc_open_read_close
start_stop_daemon: use local structure instead of global one

function                                             old     new   delta
check                                               1620    1661     +41
xmalloc_open_read_close                              171     190     +19
start_stop_daemon_main                               976     954     -22
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 2/1 up/down: 60/-22)             Total: 38 bytes

1 files changed, 16 insertions, 7 deletions

diff --git a/libbb/read.c b/libbb/read.c
index ba366cb97..e5f140f3b 100644
--- a/libbb/read.c
+++ b/libbb/read.c
@@ -208,25 +208,34 @@ ssize_t open_read_close(const char *filename, void *buf, size_t size)
 void *xmalloc_open_read_close(const char *filename, size_t *sizep)
 {
         char *buf;
-        size_t size = sizep ? *sizep : INT_MAX;
+        size_t size;
         int fd;
         off_t len;
 
         fd = open(filename, O_RDONLY);
         if (fd < 0)
                 return NULL;
+
         /* /proc/N/stat files report len 0 here */
         /* In order to make such files readable, we add small const */
-        len = xlseek(fd, 0, SEEK_END) | 0x3ff; /* + up to 1k */
-        xlseek(fd, 0, SEEK_SET);
-        if (len < size)
-                size = len;
+        size = 0x3ff; /* read only 1k on unseekable files */
+        len = lseek(fd, 0, SEEK_END) | 0x3ff; /* + up to 1k */
+        if (len != (off_t)-1) {
+                xlseek(fd, 0, SEEK_SET);
+                size = sizep ? *sizep : INT_MAX;
+                if (len < size)
+                        size = len;
+        }
+
         buf = xmalloc(size + 1);
         size = read_close(fd, buf, size);
-        if ((ssize_t)size < 0)
-                bb_perror_msg_and_die("'%s'", filename);
+        if ((ssize_t)size < 0) {
+                free(buf);
+                return NULL;
+        }
         xrealloc(buf, size + 1);
         buf[size] = '\0';
+
         if (sizep)
                 *sizep = size;
         return buf;