Even though it is set by Linux's limits.h and apparently by other OSes
too, it seems this macro is mostly bogus. On many systems, the actual
allowed max size of paths is much higher.
On Hurd, they don't even define the macro as there is no upper limit.
See MR !424.
This commit replaces two usages of PATH_MAX:
- readlink() by g_file_read_link(). I checked the GLib implementation
and could confirm it will do the proper thing, which is progressively
incrementing their buffer allocation in a loop until the buffer is big
enough to contain the symbolic link contents. Hence no need to rely on
a bogus macro which is not the actual max.
- fgets() by g_data_input_stream_read_line() which also dynamically
allocates the returned buffer, and also properly removes the newline
and adds a NUL byte (hence simpler code).
Additionally I loop through the lines of /proc/self/maps until I find
the first "r-xp" pathname. Indeed the current code was assuming that the
first line was always right. Yet on my OS at least, the first line was
GIMP executable with "r--p" permission, hence the test would fail. The
second line had the right permission. So let's assume that we want the
first executable path, looping through each line.
47fbfc2f0e