summaryrefslogtreecommitdiff
path: root/user/tlecarrour/porting_guide_for_dummies.mdwn
diff options
context:
space:
mode:
authorTanguy LE CARROUR <tanguy@bioneland.org>2012-02-02 15:02:23 +0100
committerTanguy LE CARROUR <tanguy@bioneland.org>2012-02-02 15:02:23 +0100
commit29d1a9e3e4d53057bc37ad32ddcb734a0b88a8ff (patch)
tree7ddd922f6cd8b89cebfd164567e2b87af5cb1451 /user/tlecarrour/porting_guide_for_dummies.mdwn
parent4df998f4178dec0cf29d2cdfae85d9b96d6e5052 (diff)
Add user page and patch pages for tlecarrour.
Diffstat (limited to 'user/tlecarrour/porting_guide_for_dummies.mdwn')
-rw-r--r--user/tlecarrour/porting_guide_for_dummies.mdwn203
1 files changed, 203 insertions, 0 deletions
diff --git a/user/tlecarrour/porting_guide_for_dummies.mdwn b/user/tlecarrour/porting_guide_for_dummies.mdwn
new file mode 100644
index 0000000..749344f
--- /dev/null
+++ b/user/tlecarrour/porting_guide_for_dummies.mdwn
@@ -0,0 +1,203 @@
+[[!meta copyright="Copyright © 2010 Free Software Foundation, Inc."]]
+
+[[!meta license="""[[!toggle id="license" text="GFDL 1.2+"]][[!toggleable
+id="license" text="Permission is granted to copy, distribute and/or modify this
+document under the terms of the GNU Free Documentation License, Version 1.2 or
+any later version published by the Free Software Foundation; with no Invariant
+Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license
+is included in the section entitled [[GNU Free Documentation
+License|/fdl]]."]]"""]]
+
+
+Porting Guide for Dummies
+=========================
+
+The problems addressed here were encountered while working
+on fixing **PATH_MAX** and **MAXPATHLEN**.
+
+[[!toc startlevel=2 levels=3]]
+
+
+* * *
+
+
+Test on Hurd
+------------
+
+
+### Installing the required files
+
+As `apt-get source` will download and extract many files, you may want to create a dedicated folder for the package and work from there.
+
+ mkdir PACKAGE
+ cd PACKAGE
+ sudo apt-get build-dep PACKAGE
+ apt-get source PACKAGE
+
+
+### Trying to build the package
+
+ cd PACKAGE_SOURCE
+ dpkg-buildpackage -us -uc -rfakeroot -tc
+
+
+### Test a quick fix
+
+In all the files that use **PATH_MAX**, include those lines at the beginning.
+
+ #ifndef PATH_MAX
+ #define PATH_MAX 4196
+ #endif
+
+Try to rebuild the package and see if it's solved the problem.
+If yes, you can start working on the package.
+
+
+* * *
+
+
+Basic things
+------------
+
+### Maintaining a original version
+
+ mkdir old
+ cp -r PACKAGE_SOURCE old/
+
+
+### Coding style
+
+Follow the conventions used in the source code!
+
+ if (condition) {
+ do_smthg();
+ }
+
+is not the same as:
+
+ if (condition)
+ {
+ do_smthg();
+ }
+
+and is not the same as:
+
+ if (condition)
+ do_smthg();
+
+Pay attention to spaces surrounding, or not, arithmetic signs and symbols:
+
+ a = do_smthg( b + c );
+ a = do_smthg(b+c);
+
+
+### Indentation
+
+By default use 8 spaces as the size for 1 tab.
+Then figure out if the code uses tab + 1/2 tab:
+
+ ....if (condition) {
+ ------->do_smthg();
+ ....}
+
+or tab only:
+
+ ------->if (condition) {
+ ------->------->do_smthg();
+ ------->}
+
+
+### Creating a patch
+
+ diff -Naur old/PACKAGE-VERSION PACKAGE-VERSION > fix_FTBFS4Hurd.patch
+
+
+* * *
+
+
+Known problems
+--------------
+
+### Dynamically allocated buffer returned by a function
+
+Use a static buffer
+
+### Buffer used to format an expression containing an INTEGER
+
+The length of an INTEGER in a string can be up to sizeof (int) * 3 + 1.
+
+> The usual trick for "%d" is to use the constant 'sizeof (int) * 3 + 1'.
+I included + 1 for the sign, but it's not really necessary
+if we exepect sizeof(int) >= 2, which we probably should.
+**Jérémie Koenig**
+
+ log(MAX_INT)
+ = log(2 ^ 32)
+ = 32 * log(2)
+ = 4 * 8 * log(2)
+ = sizeof(int) * 2.40823997
+ < sizeof(int) * 3
+
+
+### Proper use of realloc()
+
+use a new_buff to check if everything went fine Free buf if realloc failed (and prog doesn't exit)
+
+
+### Reading lines from file
+
+Function to read line (no size limit, ending with "\n") from a file.
+
+ +static char *get_line(FILE *f)
+ +{
+ + char *buff = NULL;
+ + char *new_buff = NULL;
+ + size_t buff_size = 0;
+ + size_t last = 0;
+ +
+ + while (!feof(f)) {
+ + buff_size = buff_size ? buff_size * 2 : BUFSIZ;
+ + new_buff = realloc(buff, buff_size);
+ + if (new_buff == NULL) {
+ + free(buff);
+ + return NULL;
+ + }
+ + buff = new_buff;
+ + if (fgets(buff + last, buff_size - last, f) == NULL) {
+ + free(buff);
+ + return NULL;
+ + }
+ + last = strlen(buff);
+ + if (buff[last - 1] == '\n')
+ + return buff;
+ + }
+ + return buff;
+ +}
+
+
+### Proper use of readlink()
+
+One has to rely on lstat() to get the size of the link that readlink() returns.
+
+Declare what you need:
+
+ char *linkname = NULL;
+ struct stat sb;
+ ssize_t len = -1;
+
+Call lstat() and check return value:
+
+ if (lstat(filename, &sb) == -1) {
+
+Create a buffer of the appropriate size and check the return value:
+
+ linkname = malloc(sb.st_size + 1);
+ if (linkname == NULL) {
+
+Call readlink(), check return value and set the null char in the linkname:
+
+ len = readlink(filename, linkname, sb.st_size + 1);
+ if (len < 0 || len > sb.st_size) {
+ ...
+ linkname[sb.st_size] = '\0';
+