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[LibOS] Fix poll() crashing on pseudo-files
The code assumed that all handles (other than TYPE_FILE and TYPE_DEV) had an associated PAL handle, which caused a crash when polling files from /proc. This change adds support for polling TYPE_STR, and also adds a check for PAL handle in all cases.
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -1,44 +1,116 @@ | ||
| /* SPDX-License-Identifier: LGPL-3.0-or-later */ | ||
| /* Copyright (C) 2021 Intel Corporation | ||
| * Paweł Marczewski <pawel@invisiblethingslab.com> | ||
| */ | ||
|
|
||
| /* Simple sanity check for poll() on various file types. */ | ||
|
|
||
| #include <err.h> | ||
| #include <errno.h> | ||
| #include <fcntl.h> | ||
| #include <poll.h> | ||
| #include <stdio.h> | ||
| #include <stdlib.h> | ||
| #include <string.h> | ||
| #include <sys/stat.h> | ||
| #include <sys/types.h> | ||
| #include <unistd.h> | ||
|
|
||
| int main(void) { | ||
| static void check_poll(int fd, short events, int revents) { | ||
| struct pollfd fds[] = { | ||
| {.fd = fd, .events = events, .revents = 0}, | ||
| }; | ||
|
|
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| int ret = poll(fds, /*nfds=*/1, /*timeout=*/0); | ||
| fprintf(stderr, "poll {events = 0x%x} = %d", events, ret); | ||
| if (ret == 1) | ||
| fprintf(stderr, "; {revents = 0x%x}", (int)fds[0].revents); | ||
| fprintf(stderr, "\n"); | ||
| fflush(stderr); | ||
| if (ret < 0) | ||
| err(1, "poll"); | ||
|
|
||
| int expected = revents ? 1 : 0; | ||
| if (ret != expected) | ||
| errx(1, "expected poll to return %d\n", expected); | ||
|
|
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| if (ret == 1 && fds[0].revents != revents) | ||
| errx(1, "expected revents to be 0x%x", revents); | ||
| } | ||
|
|
||
| static void write_byte(int fd, char c) { | ||
| ssize_t n; | ||
| do { | ||
| char c = 0; | ||
| n = write(fd, &c, sizeof(c)); | ||
| } while (n == -1 && errno == EINTR); | ||
| if (n == -1) | ||
| err(1, "write"); | ||
| if (n != 1) | ||
| errx(1, "write returned %ld", n); | ||
| } | ||
|
|
||
| static void test_pipe(void) { | ||
| printf("testing poll() on pipe...\n"); | ||
| int ret; | ||
| int fd[2]; | ||
| char string[] = "Hello, world!\n"; | ||
|
|
||
| ret = pipe(fd); | ||
| if (ret < 0) { | ||
| perror("pipe creation failed"); | ||
| return 1; | ||
| } | ||
| int fds[2]; | ||
| ret = pipe(fds); | ||
| if (ret < 0) | ||
| err(1, "pipe"); | ||
|
|
||
| struct pollfd outfds[] = { | ||
| {.fd = fd[1], .events = POLLOUT}, | ||
| }; | ||
| ret = poll(outfds, 1, -1); | ||
| if (ret <= 0) { | ||
| perror("poll with POLLOUT failed"); | ||
| return 1; | ||
| } | ||
| printf("poll(POLLOUT) returned %d file descriptors\n", ret); | ||
| check_poll(fds[1], POLLOUT, POLLOUT); | ||
| check_poll(fds[0], POLLIN, 0); | ||
|
|
||
| struct pollfd infds[] = { | ||
| {.fd = fd[0], .events = POLLIN}, | ||
| }; | ||
| size_t size = strlen(string) + 1; | ||
| if (write(fd[1], string, size) != size) { | ||
| perror("write error"); | ||
| return 1; | ||
| } | ||
| ret = poll(infds, 1, -1); | ||
| if (ret <= 0) { | ||
| perror("poll with POLLIN failed"); | ||
| return 1; | ||
| write_byte(fds[1], 0); | ||
|
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||
| check_poll(fds[0], POLLIN, POLLIN); | ||
|
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| if (close(fds[0]) < 0 || close(fds[1]) < 0) | ||
| err(1, "close"); | ||
| } | ||
|
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||
| static void test_file(const char* path, int flags, int events1, int revents1, int events2, | ||
| int revents2) { | ||
| printf("testing poll() on %s...\n", path); | ||
|
|
||
| int fd = open(path, flags, 0600); | ||
| if (fd < 0) | ||
| err(1, "open"); | ||
|
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||
| if (events1) | ||
| check_poll(fd, events1, revents1); | ||
|
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||
| if (events2) | ||
| check_poll(fd, events2, revents2); | ||
|
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| if (close(fd) < 0) | ||
| err(1, "close"); | ||
|
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||
| if (flags & O_CREAT) { | ||
| if (unlink(path) < 0) | ||
| err(1, "unlink"); | ||
| } | ||
| printf("poll(POLLIN) returned %d file descriptors\n", ret); | ||
| } | ||
|
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||
| int main(int argc, char** argv) { | ||
| setbuf(stdout, NULL); | ||
| setbuf(stderr, NULL); | ||
|
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| test_pipe(); | ||
|
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||
| /* Emulated device */ | ||
| test_file("/dev/null", O_RDWR, POLLIN, POLLIN, POLLOUT, POLLOUT); | ||
|
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| /* File in /proc/ */ | ||
| test_file("/proc/meminfo", O_RDONLY, POLLIN, POLLIN, 0, 0); | ||
|
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| /* Host file */ | ||
| test_file(argv[0], O_RDONLY, POLLIN, POLLIN, 0, 0); | ||
|
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| /* Host file (empty) */ | ||
| test_file("tmp/host_file", O_RDWR | O_CREAT | O_TRUNC, POLLIN, 0, POLLOUT, POLLOUT); | ||
|
|
||
| printf("TEST OK\n"); | ||
| return 0; | ||
| } |
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