diff options
| -rw-r--r-- | toys/posix/tail.c | 74 |
1 files changed, 70 insertions, 4 deletions
diff --git a/toys/posix/tail.c b/toys/posix/tail.c index 910b88f3..c2f71cbd 100644 --- a/toys/posix/tail.c +++ b/toys/posix/tail.c @@ -17,7 +17,7 @@ config TAIL -n output the last NUMBER lines (default 10), +X counts from start. -c output the last NUMBER bytes, +NUMBER counts from start - #-f follow FILE(s), waiting for more data to be appended [TODO] + -f follow FILE(s), waiting for more data to be appended config TAIL_SEEK bool "tail seek support" @@ -30,11 +30,20 @@ config TAIL_SEEK #define FOR_tail #include "toys.h" +#include <sys/inotify.h> + +struct file_info { + int fd; + int wd; + const char* path; +}; + GLOBALS( long lines; long bytes; int file_no; + struct file_info *files; ) struct line_list { @@ -135,10 +144,15 @@ static void do_tail(int fd, char *name) int linepop = 1; if (toys.optc > 1) { - if (TT.file_no++) xputc('\n'); + if (TT.file_no > 0) xputc('\n'); xprintf("==> %s <==\n", name); } + // -f support: cache name/descriptor + TT.files[TT.file_no].fd = dup(fd); + TT.files[TT.file_no].path = strdup(name); + ++TT.file_no; + // Are we measuring from the end of the file? if (bytes<0 || lines<0) { @@ -207,8 +221,6 @@ static void do_tail(int fd, char *name) } if (offset<len) xwrite(1, toybuf+offset, len-offset); } - - // -f support: cache name/descriptor } void tail_main(void) @@ -228,7 +240,61 @@ void tail_main(void) TT.lines = -10; } + TT.files = xmalloc(toys.optc * sizeof(struct file_info)); loopfiles(args, do_tail); // do -f stuff + if (toys.optflags & FLAG_f) { + int infd, last_wd, i; + + infd = inotify_init(); + if (infd < 0) { + perror_exit("failed to create inotify fd"); + } + + for (i = 0; i < TT.file_no; ++i) { + #define STR(x) #x + char path[sizeof("/proc/self/fd/" STR(INT_MIN))]; + + snprintf(path, sizeof(path), "/proc/self/fd/%d", TT.files[i].fd); + + TT.files[i].wd = inotify_add_watch(infd, path, IN_MODIFY); + if (TT.files[i].wd < 0) { + perror_msg("failed to add inotify watch for %s", TT.files[i].path); + continue; + } + } + + last_wd = TT.files[TT.file_no - 1].wd; + + while (1) { + struct inotify_event ev; + int len; + + len = read(infd, &ev, sizeof(ev)); + if (len < 0) { + perror_exit("inotify read failed"); + } + + for (i = 0; i < TT.file_no; ++i) { + if (ev.wd != TT.files[i].wd) { + continue; + } + + // Read until we hit the end. + while (1) { + len = read(TT.files[i].fd, toybuf, sizeof(toybuf)); + if (len <= 0) break; + + if (last_wd != TT.files[i].wd) { + last_wd = TT.files[i].wd; + xprintf("\n==> %s <==\n", TT.files[i].path); + } + + xwrite(1, toybuf, len); + } + break; + } + } + } } |