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hurd: Fix readlink() hanging on fifo

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readlink() opens the target with O_READ to be able to read the symlink
content. When the target is actually a fifo, that would hang waiting for a
writer (caught in the coreutils testsuite). We thus have to first lookup the
target without O_READ to perform io_stat and lookout for fifos, and only
after checking the symlink type, we can re-lookup with O_READ.
This commit is contained in:
Samuel Thibault 2022-09-14 18:52:52 +02:00
parent 05967faf0e
commit 9e5c991106
2 changed files with 8 additions and 2 deletions
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5
sysdeps/mach/hurd/readlink.c
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@ -31,7 +31,7 @@ __readlink (const char *file_name, char *buf, size_t len)
file_t file;
struct stat64 st;
file = __file_name_lookup (file_name, O_READ | O_NOLINK, 0);
file = __file_name_lookup (file_name, O_NOLINK, 0);
if (file == MACH_PORT_NULL)
return -1;
@ -41,6 +41,9 @@ __readlink (const char *file_name, char *buf, size_t len)
{
char *rbuf = buf;
__mach_port_deallocate (__mach_task_self (), file);
file = __file_name_lookup (file_name, O_READ | O_NOLINK, 0);
err = __io_read (file, &rbuf, &len, 0, len);
if (!err && rbuf != buf)
{

5
sysdeps/mach/hurd/readlinkat.c
View file

@ -32,7 +32,7 @@ readlinkat (int fd, const char *file_name, char *buf, size_t len)
file_t file;
struct stat64 st;
file = __file_name_lookup_at (fd, 0, file_name, O_READ | O_NOLINK, 0);
file = __file_name_lookup_at (fd, 0, file_name, O_NOLINK, 0);
if (file == MACH_PORT_NULL)
return -1;
@ -42,6 +42,9 @@ readlinkat (int fd, const char *file_name, char *buf, size_t len)
{
char *rbuf = buf;
__mach_port_deallocate (__mach_task_self (), file);
file = __file_name_lookup_at (fd, 0, file_name, O_READ | O_NOLINK, 0);
err = __io_read (file, &rbuf, &len, 0, len);
if (!err && rbuf != buf)
{