Built-in server leaks a file descriptor on every HEAD request for a static file
Nobody has claimed this yet.
Assessment
- Difficulty
- 2/5
- Estimated time
- 1-3 hours
- Newbie friendliness
- 88/100
- Issue type
- Bug
- Clarity
- Clearly specified
- Activity status
- Active
- Domain
- cli, networking
Research direction
Start in sapi/cli/php_cli_server.c at php_cli_server_begin_send_static(), then run the provided php -S and repeated curl HEAD reproduction. Done means repeated HEAD requests to a static file no longer increase open file descriptors, while normal static responses continue to work.
Written by the indexing model from the issue text.
Description
Description
Since PHP 8.2 (#8215), php_cli_server_begin_send_static() in sapi/cli/php_cli_server.c opens the static file but only stores the descriptor in client->file_fd for non-HEAD requests:
fd = open(client->request.path_translated, O_RDONLY);
...
if (client->request.request_method != PHP_HTTP_HEAD) {
client->file_fd = fd;
}
For HEAD, fd is never stored and never closed. Each HEAD request to a static file leaks one descriptor; once RLIMIT_NOFILE is reached every request fails with 404 ... Too many open files. A monitoring probe doing HEAD / every 40 s takes down php -S in ~11 hours.
Affected: PHP-8.2, PHP-8.3, PHP-8.4, PHP-8.5, master. PHP 8.1 is not affected (no HEAD special-casing).
Reproduction:
mkdir t && echo hi > t/index.html
php -S 127.0.0.1:8080 -t t &
for i in $(seq 100); do curl -sI http://127.0.0.1:8080/ >/dev/null; done
ls -l /proc/$!/fd | grep -c index.html # 100
Suggested fix — close the descriptor when it is not handed to the content sender (Content-Length uses client->request.sb.st_size from the earlier stat, so the fd is not needed for HEAD at all):
if (client->request.request_method != PHP_HTTP_HEAD) {
client->file_fd = fd;
} else {
close(fd);
}
PHP Version
PHP 8.2 – 8.5, master
Operating System
Linux (any)
- Dominant language
- C
- Stars
- 40.4k
- Forks
- 8.2k
- Avg merge
- 2d 14h
- Merged PRs (30d)
- 112
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
More from php/php-src
-
Bug Status: Needs Triage
Difficulty 2/5 1-3 hours Newbie friendliness 76/100
-
Bug Status: Needs Triage
Difficulty 1/5 Under an hour Newbie friendliness 90/100
-
Bug Status: Needs Triage
Difficulty 2/5 1-3 hours Newbie friendliness 78/100
-
Bug Category: Tests Status: Verified
Difficulty 2/5 1-3 hours Newbie friendliness 68/100
-
Bug SAPI: fpm Status: Needs Triage
Difficulty 2/5 1-3 hours Newbie friendliness 65/100
Similar issues
-
Difficulty 2/5 1-3 hours Newbie friendliness 84/100
-
level/task module/gcp type/bug
Difficulty 2/5 1-3 hours Newbie friendliness 85/100
-
Difficulty 1/5 Under an hour Newbie friendliness 86/100
hapostgres/pg_auto_failover#1190 ·
-
docs
Difficulty 1/5 Under an hour Newbie friendliness 85/100
-
P3 sonic-vpp
Difficulty 2/5 1-3 hours Newbie friendliness 88/100
sonic-net/sonic-buildimage#29662 ·