tailf: use size_t and fwrite()

Let's use size_t for number of output lines and use fwrite() rather
than while() { putchar() };

Signed-off-by: Karel Zak <kzak@redhat.com>

diff --git a/text-utils/tailf.c b/text-utils/tailf.c
index e0c86a7ba4ae8e1ede90eed1ec95c22d96ecc2f3..603904924f959d0dc10ca61dc9a088010b579f67 100644 (file)
--- a/text-utils/tailf.c
+++ b/text-utils/tailf.c
@@ -50,8 +50,8 @@
 
 #define DEFAULT_LINES  10
 
-static void
-tailf(const char *filename, unsigned long lines, struct stat *st)
+/* st->st_size has to be greater than zero! */
+static void tailf(const char *filename, size_t lines, struct stat *st)
 {
        int fd;
        size_t i;
@@ -60,7 +60,8 @@ tailf(const char *filename, unsigned long lines, struct stat *st)
        if (!(fd = open(filename, O_RDONLY)))
                err(EXIT_FAILURE, _("cannot open %s"), filename);
        data = mmap(0, st->st_size, PROT_READ, MAP_SHARED, fd, 0);
-       i = (size_t)st->st_size - 1;
+       i = (size_t) st->st_size - 1;
+
        /* humans do not think last new line in a file should be counted,
         * in that case do off by one from counter point of view */
        if (data[i] == '\n')
@@ -74,15 +75,15 @@ tailf(const char *filename, unsigned long lines, struct stat *st)
                }
                i--;
        }
-       while (i < (size_t)st->st_size)
-               putchar(data[i++]);
+
+       fwrite(data + i, st->st_size - i, 1, stdout);
+
        munmap(data, st->st_size);
        close(fd);
        fflush(stdout);
 }
 
-static void
-roll_file(const char *filename, struct stat *old)
+static void roll_file(const char *filename, struct stat *old)
 {
        char buf[BUFSIZ];
        int fd;
@@ -124,8 +125,7 @@ roll_file(const char *filename, struct stat *old)
        close(fd);
 }
 
-static void
-watch_file(const char *filename, struct stat *old)
+static void watch_file(const char *filename, struct stat *old)
 {
        do {
                roll_file(filename, old);
@@ -139,8 +139,7 @@ watch_file(const char *filename, struct stat *old)
 #define EVENTS         (IN_MODIFY|IN_DELETE_SELF|IN_MOVE_SELF|IN_UNMOUNT)
 #define NEVENTS                4
 
-static int
-watch_file_inotify(const char *filename, struct stat *old)
+static int watch_file_inotify(const char *filename, struct stat *old)
 {
        char buf[ NEVENTS * sizeof(struct inotify_event) ];
        int fd, ffd, e;
@@ -208,7 +207,7 @@ static void __attribute__ ((__noreturn__)) usage(FILE *out)
 }
 
 /* parses -N option */
-static long old_style_option(int *argc, char **argv, unsigned long *lines)
+static long old_style_option(int *argc, char **argv, size_t *lines)
 {
        int i = 1, nargs = *argc, ret = 0;
 
@@ -231,7 +230,7 @@ static long old_style_option(int *argc, char **argv, unsigned long *lines)
 int main(int argc, char **argv)
 {
        const char *filename;
-       unsigned long lines;
+       size_t lines;
        int ch;
        struct stat st;
 
@@ -254,11 +253,8 @@ int main(int argc, char **argv)
                switch ((char)ch) {
                case 'n':
                case 'N':
-                       if (optarg[0] == '-')
-                               errx(EXIT_FAILURE, "%s: %s",
-                                    _("failed to parse number of lines"), optarg);
-                       lines =
-                           strtoul_or_err(optarg, _("failed to parse number of lines"));
+                       lines = strtoul_or_err(optarg,
+                                       _("failed to parse number of lines"));
                        break;
                case 'V':
                        printf(UTIL_LINUX_VERSION);