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introduce safe_poll (fixes a problem in top)

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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
2007-09-27 10:09:59 +00:00
parent c9dc2ac578
commit 5d61e71c3a
13 changed files with 65 additions and 30 deletions
Download Patch File Download Diff File Expand all files Collapse all files

4
editors/vi.c
View File

@@ -2139,7 +2139,7 @@ static int mysleep(int hund) // sleep for 'h' 1/100 seconds
pfd[0].fd = 0;
pfd[0].events = POLLIN;
return poll(pfd, 1, hund*10) > 0;
return safe_poll(pfd, 1, hund*10) > 0;
}
#define readbuffer bb_common_bufsiz1
@@ -2221,7 +2221,7 @@ static char readit(void) // read (maybe cursor) key from stdin
pfd[0].events = POLLIN;
// Wait 50 ms
// keep reading while there are input chars and room in buffer
while (poll(pfd, 1, 50) > 0 && n <= (MAX_LINELEN - 5)) {
while (safe_poll(pfd, 1, 50) > 0 && n <= (MAX_LINELEN - 5)) {
// read the rest of the ESC string
int r = read(0, readbuffer + n, MAX_LINELEN - n);
if (r > 0)

8
include/libbb.h
View File

@@ -451,8 +451,14 @@ extern FILE *fopen_or_warn(const char *filename, const char *mode);
/* "Opens" stdin if filename is special, else just opens file: */
extern FILE *fopen_or_warn_stdin(const char *filename);
/* Wrapper which restarts poll on EINTR or ENOMEM.
* On other errors complains [perror("poll")] and returns.
* Warning! May take (much) longer than timeout_ms to return!
* If this is a problem, use bare poll and open-code EINTR/ENOMEM handling */
int safe_poll(struct pollfd *ufds, nfds_t nfds, int timeout_ms);
/* Convert each alpha char in str to lower-case */
extern char* str_tolower(char *str);
char* str_tolower(char *str);
char *utoa(unsigned n);
char *itoa(int n);

1
libbb/Kbuild
View File

@@ -71,6 +71,7 @@ lib-y += recursive_action.o
lib-y += remove_file.o
lib-y += restricted_shell.o
lib-y += run_shell.o
lib-y += safe_poll.o
lib-y += safe_strncpy.o
lib-y += safe_write.o
lib-y += setup_environment.o

34
libbb/safe_poll.c Normal file
View File

@@ -0,0 +1,34 @@
/* vi: set sw=4 ts=4: */
/*
* Utility routines.
*
* Copyright (C) 2007 by Denys Vlasenko <vda.linux@googlemail.com>
*
* Licensed under GPLv2, see file LICENSE in this tarball for details.
*/
#include "libbb.h"
/* Wrapper which restarts poll on EINTR or ENOMEM.
* On other errors does perror("poll") and returns.
* Warning! May take longer than timeout_ms to return! */
int safe_poll(struct pollfd *ufds, nfds_t nfds, int timeout)
{
while (1) {
int n = poll(ufds, nfds, timeout);
if (n >= 0)
return n;
/* Make sure we inch towards completion */
if (timeout > 0)
timeout--;
/* E.g. strace causes poll to return this */
if (errno == EINTR)
continue;
/* Kernel is very low on memory. Retry. */
/* I doubt many callers would handle this correctly! */
if (errno == ENOMEM)
continue;
bb_perror_msg("poll");
return n;
}
}

2
libbb/safe_strncpy.c
View File

@@ -10,7 +10,7 @@
#include "libbb.h"
/* Like strncpy but make sure the resulting string is always 0 terminated. */
char * safe_strncpy(char *dst, const char *src, size_t size)
char *safe_strncpy(char *dst, const char *src, size_t size)
{
if (!size) return dst;
dst[--size] = '\0';

3
miscutils/microcom.c
View File

@@ -105,8 +105,7 @@ int microcom_main(int argc, char **argv)
pfd[1].events = POLLIN;
while (1) {
int i;
while (-1 == poll(pfd, 2, -1) && EINTR == errno)
continue;
safe_poll(pfd, 2, -1);
for (i = 0; i < 2; ++i) {
if (pfd[i].revents & POLLIN) {
len = read(pfd[i].fd, bb_common_bufsiz1, COMMON_BUFSIZE);

6
networking/httpd.c
View File

@@ -1073,12 +1073,8 @@ static NOINLINE void cgi_io_loop_and_exit(int fromCgi_rd, int toCgi_wr, int post
}
/* Now wait on the set of sockets */
count = poll(pfd, 3, -1);
count = safe_poll(pfd, 3, -1);
if (count <= 0) {
#if 0
if (errno == EINTR)
continue;
#endif
#if 0
if (waitpid(pid, &status, WNOHANG) <= 0) {
/* Weird. CGI didn't exit and no fd's

4
networking/tftp.c
View File

@@ -225,7 +225,7 @@ static int tftp( USE_GETPUT(const int cmd,)
/* Receive packet */
/*pfd[0].fd = socketfd;*/
pfd[0].events = POLLIN;
switch (poll(pfd, 1, waittime_ms)) {
switch (safe_poll(pfd, 1, waittime_ms)) {
unsigned from_port;
case 1:
from->len = peer_lsa->len;
@@ -262,7 +262,7 @@ static int tftp( USE_GETPUT(const int cmd,)
goto send_again; /* resend last sent pkt */
default:
bb_perror_msg("poll");
/*bb_perror_msg("poll"); - done in safe_poll */
goto ret;
}
process_pkt:

2
networking/traceroute.c
View File

@@ -543,7 +543,7 @@ wait_for_reply(int sock, struct sockaddr_in *fromp)
pfd[0].fd = sock;
pfd[0].events = POLLIN;
if (poll(pfd, 1, waittime * 1000) > 0)
if (safe_poll(pfd, 1, waittime * 1000) > 0)
cc = recvfrom(sock, packet, sizeof(packet), 0,
(struct sockaddr *)fromp, &fromlen);
return cc;

7
networking/udhcp/arpping.c
View File

@@ -81,12 +81,9 @@ int arpping(uint32_t test_ip, uint32_t from_ip, uint8_t *from_mac, const char *i
unsigned prevTime = monotonic_us();
pfd[0].events = POLLIN;
r = poll(pfd, 1, timeout_ms);
r = safe_poll(pfd, 1, timeout_ms);
if (r < 0) {
if (errno != EINTR) {
bb_perror_msg("poll");
break;
}
break;
} else if (r) {
if (read(s, &arp, sizeof(arp)) < 0)
break;

14
networking/zcip.c
View File

@@ -300,7 +300,12 @@ int zcip_main(int argc, char **argv)
VDBG("...wait %d %s nprobes=%u, nclaims=%u\n",
timeout_ms, intf, nprobes, nclaims);
switch (poll(fds, 1, timeout_ms)) {
switch (safe_poll(fds, 1, timeout_ms)) {
default:
/*bb_perror_msg("poll"); - done in safe_poll */
return EXIT_FAILURE;
// timeout
case 0:
@@ -388,6 +393,7 @@ int zcip_main(int argc, char **argv)
break;
} // switch (state)
break; // case 0 (timeout)
// packets arriving
case 1:
// We need to adjust the timeout in case we didn't receive
@@ -519,13 +525,9 @@ int zcip_main(int argc, char **argv)
nclaims = 0;
break;
} // switch state
break; // case 1 (packets arriving)
default:
why = "poll";
goto bad;
} // switch poll
}
} // while (1)
bad:
bb_perror_msg("%s, %s", intf, why);
return EXIT_FAILURE;

2
procps/top.c
View File

@@ -924,7 +924,7 @@ int top_main(int argc, char **argv)
#if !ENABLE_FEATURE_USE_TERMIOS
sleep(interval);
#else
if (poll(pfd, 1, interval * 1000) != 0) {
if (safe_poll(pfd, 1, interval * 1000) > 0) {
if (read(0, &c, 1) != 1) /* signal */
break;
if (c == initial_settings.c_cc[VINTR])

8
runit/svlogd.c
View File

@@ -665,7 +665,7 @@ static ssize_t ndelay_read(int fd, void *buf, size_t count)
}
/* Used for reading stdin */
static int buffer_pread(int fd, char *s, unsigned len)
static int buffer_pread(/*int fd, */char *s, unsigned len)
{
unsigned now;
struct pollfd input;
@@ -709,7 +709,7 @@ static int buffer_pread(int fd, char *s, unsigned len)
poll(&input, 1, i * 1000);
sigprocmask(SIG_BLOCK, blocked_sigset, NULL);
i = ndelay_read(fd, s, len);
i = ndelay_read(0, s, len);
if (i >= 0)
break;
if (errno == EINTR)
@@ -909,7 +909,7 @@ int svlogd_main(int argc, char **argv)
if (!np && !exitasap) {
i = linemax - stdin_cnt; /* avail. bytes at tail */
if (i >= 128) {
i = buffer_pread(0, lineptr + stdin_cnt, i);
i = buffer_pread(/*0, */lineptr + stdin_cnt, i);
if (i <= 0) /* EOF or error on stdin */
exitasap = 1;
else {
@@ -966,7 +966,7 @@ int svlogd_main(int argc, char **argv)
/* read/write repeatedly until we see it */
while (ch != '\n') {
/* lineptr is emptied now, safe to use as buffer */
stdin_cnt = exitasap ? -1 : buffer_pread(0, lineptr, linemax);
stdin_cnt = exitasap ? -1 : buffer_pread(/*0, */lineptr, linemax);
if (stdin_cnt <= 0) { /* EOF or error on stdin */
exitasap = 1;
lineptr[0] = ch = '\n';