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https://github.com/sheumann/hush.git
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introduce safe_poll (fixes a problem in top)
function old new delta safe_poll - 77 +77 svlogd_main 1470 1466 -4 zcip_main 1530 1524 -6 forkexec 1345 1338 -7 decode_format_string 795 788 -7 collect_blk 474 467 -7 buffer_pread 540 532 -8 tftp 1182 1172 -10 microcom_main 763 749 -14 arpping 441 424 -17 ------------------------------------------------------------------------------ (add/remove: 1/0 grow/shrink: 0/9 up/down: 77/-80) Total: -3 bytes text data bss dec hex filename 770162 1034 10404 781600 bed20 busybox_old 770158 1034 10404 781596 bed1c busybox_unstripped
This commit is contained in:
Denis Vlasenko
parent
c9dc2ac578
commit
5d61e71c3a
@ -2139,7 +2139,7 @@ static int mysleep(int hund) // sleep for 'h' 1/100 seconds
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pfd[0].fd = 0;
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pfd[0].events = POLLIN;
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return poll(pfd, 1, hund*10) > 0;
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return safe_poll(pfd, 1, hund*10) > 0;
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}
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#define readbuffer bb_common_bufsiz1
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@ -2221,7 +2221,7 @@ static char readit(void) // read (maybe cursor) key from stdin
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pfd[0].events = POLLIN;
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// Wait 50 ms
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// keep reading while there are input chars and room in buffer
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while (poll(pfd, 1, 50) > 0 && n <= (MAX_LINELEN - 5)) {
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while (safe_poll(pfd, 1, 50) > 0 && n <= (MAX_LINELEN - 5)) {
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// read the rest of the ESC string
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int r = read(0, readbuffer + n, MAX_LINELEN - n);
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if (r > 0)
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@ -451,8 +451,14 @@ extern FILE *fopen_or_warn(const char *filename, const char *mode);
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/* "Opens" stdin if filename is special, else just opens file: */
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extern FILE *fopen_or_warn_stdin(const char *filename);
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/* Wrapper which restarts poll on EINTR or ENOMEM.
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* On other errors complains [perror("poll")] and returns.
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* Warning! May take (much) longer than timeout_ms to return!
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* If this is a problem, use bare poll and open-code EINTR/ENOMEM handling */
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int safe_poll(struct pollfd *ufds, nfds_t nfds, int timeout_ms);
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/* Convert each alpha char in str to lower-case */
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extern char* str_tolower(char *str);
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char* str_tolower(char *str);
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char *utoa(unsigned n);
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char *itoa(int n);
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@ -71,6 +71,7 @@ lib-y += recursive_action.o
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lib-y += remove_file.o
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lib-y += restricted_shell.o
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lib-y += run_shell.o
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lib-y += safe_poll.o
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lib-y += safe_strncpy.o
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lib-y += safe_write.o
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lib-y += setup_environment.o
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34
libbb/safe_poll.c
Normal file
34
libbb/safe_poll.c
Normal file
@ -0,0 +1,34 @@
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/* vi: set sw=4 ts=4: */
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/*
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* Utility routines.
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*
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* Copyright (C) 2007 by Denys Vlasenko <vda.linux@googlemail.com>
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*
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* Licensed under GPLv2, see file LICENSE in this tarball for details.
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*/
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#include "libbb.h"
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/* Wrapper which restarts poll on EINTR or ENOMEM.
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* On other errors does perror("poll") and returns.
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* Warning! May take longer than timeout_ms to return! */
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int safe_poll(struct pollfd *ufds, nfds_t nfds, int timeout)
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{
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while (1) {
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int n = poll(ufds, nfds, timeout);
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if (n >= 0)
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return n;
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/* Make sure we inch towards completion */
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if (timeout > 0)
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timeout--;
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/* E.g. strace causes poll to return this */
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if (errno == EINTR)
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continue;
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/* Kernel is very low on memory. Retry. */
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/* I doubt many callers would handle this correctly! */
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if (errno == ENOMEM)
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continue;
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bb_perror_msg("poll");
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return n;
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}
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}
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@ -10,7 +10,7 @@
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#include "libbb.h"
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/* Like strncpy but make sure the resulting string is always 0 terminated. */
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char * safe_strncpy(char *dst, const char *src, size_t size)
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char *safe_strncpy(char *dst, const char *src, size_t size)
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{
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if (!size) return dst;
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dst[--size] = '\0';
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@ -105,8 +105,7 @@ int microcom_main(int argc, char **argv)
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pfd[1].events = POLLIN;
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while (1) {
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int i;
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while (-1 == poll(pfd, 2, -1) && EINTR == errno)
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continue;
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safe_poll(pfd, 2, -1);
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for (i = 0; i < 2; ++i) {
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if (pfd[i].revents & POLLIN) {
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len = read(pfd[i].fd, bb_common_bufsiz1, COMMON_BUFSIZE);
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@ -1073,12 +1073,8 @@ static NOINLINE void cgi_io_loop_and_exit(int fromCgi_rd, int toCgi_wr, int post
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}
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/* Now wait on the set of sockets */
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count = poll(pfd, 3, -1);
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count = safe_poll(pfd, 3, -1);
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if (count <= 0) {
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#if 0
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if (errno == EINTR)
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continue;
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#endif
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#if 0
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if (waitpid(pid, &status, WNOHANG) <= 0) {
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/* Weird. CGI didn't exit and no fd's
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@ -225,7 +225,7 @@ static int tftp( USE_GETPUT(const int cmd,)
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/* Receive packet */
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/*pfd[0].fd = socketfd;*/
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pfd[0].events = POLLIN;
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switch (poll(pfd, 1, waittime_ms)) {
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switch (safe_poll(pfd, 1, waittime_ms)) {
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unsigned from_port;
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case 1:
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from->len = peer_lsa->len;
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@ -262,7 +262,7 @@ static int tftp( USE_GETPUT(const int cmd,)
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goto send_again; /* resend last sent pkt */
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default:
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bb_perror_msg("poll");
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/*bb_perror_msg("poll"); - done in safe_poll */
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goto ret;
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}
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process_pkt:
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@ -543,7 +543,7 @@ wait_for_reply(int sock, struct sockaddr_in *fromp)
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pfd[0].fd = sock;
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pfd[0].events = POLLIN;
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if (poll(pfd, 1, waittime * 1000) > 0)
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if (safe_poll(pfd, 1, waittime * 1000) > 0)
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cc = recvfrom(sock, packet, sizeof(packet), 0,
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(struct sockaddr *)fromp, &fromlen);
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return cc;
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@ -81,12 +81,9 @@ int arpping(uint32_t test_ip, uint32_t from_ip, uint8_t *from_mac, const char *i
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unsigned prevTime = monotonic_us();
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pfd[0].events = POLLIN;
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r = poll(pfd, 1, timeout_ms);
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r = safe_poll(pfd, 1, timeout_ms);
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if (r < 0) {
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if (errno != EINTR) {
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bb_perror_msg("poll");
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break;
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}
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break;
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} else if (r) {
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if (read(s, &arp, sizeof(arp)) < 0)
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break;
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@ -300,7 +300,12 @@ int zcip_main(int argc, char **argv)
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VDBG("...wait %d %s nprobes=%u, nclaims=%u\n",
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timeout_ms, intf, nprobes, nclaims);
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switch (poll(fds, 1, timeout_ms)) {
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switch (safe_poll(fds, 1, timeout_ms)) {
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default:
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/*bb_perror_msg("poll"); - done in safe_poll */
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return EXIT_FAILURE;
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// timeout
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case 0:
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@ -388,6 +393,7 @@ int zcip_main(int argc, char **argv)
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break;
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} // switch (state)
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break; // case 0 (timeout)
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// packets arriving
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case 1:
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// We need to adjust the timeout in case we didn't receive
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@ -519,13 +525,9 @@ int zcip_main(int argc, char **argv)
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nclaims = 0;
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break;
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} // switch state
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break; // case 1 (packets arriving)
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default:
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why = "poll";
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goto bad;
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} // switch poll
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}
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} // while (1)
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bad:
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bb_perror_msg("%s, %s", intf, why);
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return EXIT_FAILURE;
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@ -924,7 +924,7 @@ int top_main(int argc, char **argv)
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#if !ENABLE_FEATURE_USE_TERMIOS
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sleep(interval);
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#else
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if (poll(pfd, 1, interval * 1000) != 0) {
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if (safe_poll(pfd, 1, interval * 1000) > 0) {
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if (read(0, &c, 1) != 1) /* signal */
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break;
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if (c == initial_settings.c_cc[VINTR])
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@ -665,7 +665,7 @@ static ssize_t ndelay_read(int fd, void *buf, size_t count)
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}
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/* Used for reading stdin */
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static int buffer_pread(int fd, char *s, unsigned len)
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static int buffer_pread(/*int fd, */char *s, unsigned len)
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{
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unsigned now;
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struct pollfd input;
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@ -709,7 +709,7 @@ static int buffer_pread(int fd, char *s, unsigned len)
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poll(&input, 1, i * 1000);
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sigprocmask(SIG_BLOCK, blocked_sigset, NULL);
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i = ndelay_read(fd, s, len);
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i = ndelay_read(0, s, len);
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if (i >= 0)
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break;
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if (errno == EINTR)
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@ -909,7 +909,7 @@ int svlogd_main(int argc, char **argv)
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if (!np && !exitasap) {
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i = linemax - stdin_cnt; /* avail. bytes at tail */
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if (i >= 128) {
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i = buffer_pread(0, lineptr + stdin_cnt, i);
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i = buffer_pread(/*0, */lineptr + stdin_cnt, i);
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if (i <= 0) /* EOF or error on stdin */
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exitasap = 1;
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else {
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@ -966,7 +966,7 @@ int svlogd_main(int argc, char **argv)
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/* read/write repeatedly until we see it */
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while (ch != '\n') {
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/* lineptr is emptied now, safe to use as buffer */
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stdin_cnt = exitasap ? -1 : buffer_pread(0, lineptr, linemax);
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stdin_cnt = exitasap ? -1 : buffer_pread(/*0, */lineptr, linemax);
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if (stdin_cnt <= 0) { /* EOF or error on stdin */
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exitasap = 1;
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lineptr[0] = ch = '\n';
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