dpkg-split: Rewrite mksplit in C

1 files changed, 209 insertions, 16 deletions

diff --git a/dpkg-split/split.c b/dpkg-split/split.c
index b583a46dc..d5d75f65b 100644
--- a/dpkg-split/split.c
+++ b/dpkg-split/split.c
@@ -3,6 +3,7 @@
  * split.c - splitting archives
  *
  * Copyright © 1995 Ian Jackson <ian@chiark.greenend.org.uk>
+ * Copyright © 2010 Guillem Jover <guillem@debian.org>
  *
  * This is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -21,11 +22,17 @@
 #include <config.h>
 #include <compat.h>
 
+#include <sys/types.h>
 #include <sys/stat.h>
+#include <sys/wait.h>
 
 #include <limits.h>
+#include <errno.h>
 #include <fcntl.h>
+#include <libgen.h>
 #include <string.h>
+#include <ctype.h>
+#include <time.h>
 #include <unistd.h>
 #include <stdlib.h>
 #include <stdio.h>
@@ -33,16 +40,210 @@
 #include <dpkg/i18n.h>
 #include <dpkg/dpkg.h>
 #include <dpkg/dpkg-db.h>
+#include <dpkg/subproc.h>
+#include <dpkg/buffer.h>
+#include <dpkg/ar.h>
 #include <dpkg/myopt.h>
 
 #include "dpkg-split.h"
 
+static char *
+deb_field(const char *filename, const char *field)
+{
+	pid_t pid;
+	int p[2];
+	struct varbuf buf = VARBUF_INIT;
+	char *end;
+
+	m_pipe(p);
+
+	pid = subproc_fork();
+	if (pid == 0) {
+		/* Child writes to pipe. */
+		m_dup2(p[1], 1);
+		close(p[0]);
+		close(p[1]);
+
+		execlp(BACKEND, BACKEND, "--field", filename, field, NULL);
+		ohshite(_("failed to exec dpkg-deb to extract field value"));
+	}
+	close(p[1]);
+
+	/* Parant reads from pipe. */
+	varbufreset(&buf);
+	fd_vbuf_copy(p[0], &buf, -1, _("dpkg-deb field extraction"));
+	varbufaddc(&buf, '\0');
+
+	close(p[0]);
+
+	subproc_wait_check(pid, _("dpkg-deb field extraction"), PROCPIPE);
+
+	/* Trim down trailing junk. */
+	for (end = buf.buf + strlen(buf.buf) - 1; end - buf.buf >= 1; end--)
+		if (isspace(*end))
+			*end = '\0';
+		else
+			break;
+
+	return varbuf_detach(&buf);
+}
+
+/* Cleanup filename for use in crippled msdos systems. */
+static char *
+clean_msdos_filename(char *filename)
+{
+	char *d, *s;
+
+	for (s = d = filename; *s; d++, s++) {
+		if (*s == '+')
+			*d = 'x';
+		else if (isupper(*s))
+			*d = tolower(*s);
+		else if (islower(*s) || isdigit(*s))
+			*d = *s;
+		else
+			s++;
+	}
+
+	return filename;
+}
+
+static int
+mksplit(const char *file_src, const char *prefix, size_t partsize,
+        size_t maxpartsize, bool msdos)
+{
+	int fd_src;
+	struct stat st;
+	char hash[MD5HASHLEN + 1];
+	char *package, *version;
+	int nparts, curpart;
+	off_t startat;
+	char *prefixdir = NULL, *msdos_prefix = NULL;
+	struct varbuf file_dst = VARBUF_INIT;
+	struct varbuf partmagic = VARBUF_INIT;
+	struct varbuf partname = VARBUF_INIT;
+	char *partdata;
+
+	fd_src = open(file_src, O_RDONLY);
+	if (fd_src < 0)
+		ohshite(_("unable to open source file `%.250s'"), file_src);
+	if (fstat(fd_src, &st))
+		ohshite(_("unable to fstat source file"));
+	if (!S_ISREG(st.st_mode))
+		ohshit(_("source file `%.250s' not a plain file"), file_src);
+
+	fd_md5(fd_src, hash, -1, "md5hash");
+	lseek(fd_src, 0, SEEK_SET);
+
+	/* FIXME: Use libdpkg-deb. */
+	package = deb_field(file_src, "Package");
+	version = deb_field(file_src, "Version");
+
+	nparts = (st.st_size + partsize - 1) / partsize;
+
+	setvbuf(stdout, NULL, _IONBF, 0);
+
+	printf("Splitting package %s into %d parts: ", package, nparts);
+
+	if (msdos) {
+		char *t;
+
+		t = m_strdup(prefix);
+		prefixdir = m_strdup(dirname(t));
+		free(t);
+
+		t = m_strdup(prefix);
+		msdos_prefix = m_strdup(basename(t));
+		free(t);
+
+		prefix = clean_msdos_filename(msdos_prefix);
+	}
+
+	partdata = m_malloc(partsize);
+	curpart = 1;
+
+	for (startat = 0; startat < st.st_size; startat += partsize) {
+		int fd_dst;
+		ssize_t partrealsize;
+
+		varbufreset(&file_dst);
+		/* Generate output filename. */
+		if (msdos) {
+			struct varbuf refname = VARBUF_INIT;
+			int prefix_max;
+
+			varbufprintf(&refname, "%dof%d", curpart, nparts);
+			prefix_max = max(8 - strlen(refname.buf), 0);
+			varbufprintf(&file_dst, "%s/%.*s%.8s.deb",
+			             prefixdir, prefix_max, prefix,
+			             refname.buf);
+			varbuf_destroy(&refname);
+		} else {
+			varbufprintf(&file_dst, "%s.%dof%d.deb",
+			             prefix, curpart, nparts);
+		}
+
+		/* Read data from the original package. */
+		partrealsize = read(fd_src, partdata, partsize);
+		if (partrealsize < 0)
+			ohshite("mksplit: read");
+
+		if ((size_t)partrealsize > maxpartsize) {
+			ohshit("Header is too long, making part too long. "
+			       "Your package name or version\n"
+			       "numbers must be extraordinarily long, "
+			       "or something. Giving up.\n");
+		}
+
+		/* Split the data. */
+		fd_dst = open(file_dst.buf, O_CREAT | O_WRONLY, 0644);
+		if (fd_dst < 0)
+			ohshite(_("unable to open file '%s'"), file_dst.buf);
+
+		/* Write the ar header. */
+		dpkg_ar_put_magic(file_dst.buf, fd_dst);
+
+		/* Write the debian-split part. */
+		varbufprintf(&partmagic, "%s\n%s\n%s\n%s\n%zu\n%zu\n%d/%d\n",
+		             SPLITVERSION, package, version, hash,
+		             st.st_size, partsize, curpart, nparts);
+		dpkg_ar_member_put_mem(file_dst.buf, fd_dst, PARTMAGIC,
+		                       partmagic.buf, partmagic.used);
+		varbufreset(&partmagic);
+
+		/* Write the data part. */
+		varbufprintf(&partname, "data.%d", curpart);
+		dpkg_ar_member_put_mem(file_dst.buf, fd_dst, partname.buf,
+		                       partdata, (size_t)partrealsize);
+		varbufreset(&partname);
+
+		close(fd_dst);
+
+		printf("%d ", curpart);
+
+		curpart++;
+	}
+
+	varbuf_destroy(&file_dst);
+	varbuf_destroy(&partname);
+	varbuf_destroy(&partmagic);
+	free(partdata);
+
+	free(prefixdir);
+	free(msdos_prefix);
+
+	close(fd_src);
+
+	printf("done\n");
+
+	return 0;
+}
+
 void do_split(const char *const *argv) {
   const char *sourcefile, *prefix;
   char *palloc;
-  int l, fd;
-  char partsizebuf[30], lengthbuf[30], partsizeallowbuf[30];
-  struct stat stab;
+  int l;
+  size_t partsize;
 
   sourcefile= *argv++;
   if (!sourcefile)
@@ -60,17 +261,9 @@ void do_split(const char *const *argv) {
     }
     prefix= palloc;
   }
-  sprintf(partsizebuf,"%ld",maxpartsize-HEADERALLOWANCE);
-  sprintf(partsizeallowbuf,"%ld",maxpartsize);
-  fd= open(sourcefile,O_RDONLY);
-  if (fd < 0)
-    ohshite(_("unable to open source file `%.250s'"), sourcefile);
-  if (fstat(fd,&stab)) ohshite(_("unable to fstat source file"));
-  if (!S_ISREG(stab.st_mode)) ohshit(_("source file `%.250s' not a plain file"),sourcefile);
-  sprintf(lengthbuf,"%lu",(unsigned long)stab.st_size);
-  m_dup2(fd,0);
-  execl(MKSPLITSCRIPT,MKSPLITSCRIPT,
-        sourcefile,partsizebuf,prefix,lengthbuf,partsizeallowbuf,msdos?"yes":"no",
-        NULL);
-  ohshite(_("unable to exec mksplit"));
+  partsize = maxpartsize - HEADERALLOWANCE;
+
+  mksplit(sourcefile, prefix, partsize, maxpartsize, msdos);
+
+  exit(0);
 }