1 files changed, 151 insertions, 0 deletions
diff --git a/src/util.c b/src/util.c
index 91954dd..ed93e6b 100644
--- a/src/util.c
+++ b/src/util.c
@@ -6,6 +6,9 @@
 #include <errno.h>
 #include <limits.h>
 #include <unistd.h>
+#include <sys/mman.h>
+#include <fcntl.h>
+
 #include "util.h"
 
 void statistics(DB *db) {
@@ -104,3 +107,151 @@ int isdirectory(const char *path) {
 
     return !!S_ISDIR(st.st_mode);
 }
+
+
+#define MMAPSIZE (100*1024*1024)
+#define BUFSIZE (1024*1024)
+
+int copy_fd(int sfd, int dfd, uint32_t l) {
+    off_t src_o, dst_o;
+    void *src_p, *dst_p;
+    void *buf = NULL;
+    int r = -1;
+    struct stat st;
+
+    if ((src_o = lseek(sfd, 0, SEEK_CUR)) == (off_t) -1) {
+        fprintf(stderr, "lseek(): %s\n", strerror(errno));
+        goto finish;
+    }
+
+    if (fstat(sfd, &st) < 0) {
+        fprintf(stderr, "fstat(): %s\n", strerror(errno));
+        goto finish;
+    }
+
+    if (l == (uint32_t) -1 || l >= st.st_size - src_o)
+        l = st.st_size - src_o;
+
+    if ((dst_o = lseek(dfd, 0, SEEK_CUR)) == (off_t) -1) {
+        fprintf(stderr, "lseek(): %s\n", strerror(errno));
+        goto finish;
+    }
+    
+    if (fstat(dfd, &st) < 0) {
+        fprintf(stderr, "fstat(): %s\n", strerror(errno));
+        goto finish;
+    }
+    
+    if (dst_o+l > st.st_size)
+        if (ftruncate(dfd, dst_o+l) < 0) {
+            fprintf(stderr, "ftruncate(): %s\n", strerror(errno));
+            goto finish;
+        }
+
+    if (l > BUFSIZE) {
+        uint32_t m = l < MMAPSIZE ? l : MMAPSIZE;
+
+        while (l > 0) {
+            if ((src_p = mmap(NULL, m, PROT_READ, MAP_SHARED, sfd, src_o)) == MAP_FAILED)
+                break;
+            
+            if ((dst_p = mmap(NULL, m, PROT_READ|PROT_WRITE, MAP_SHARED, dfd, dst_o)) == MAP_FAILED) {
+                munmap(src_p, m);
+                break;
+            }
+            
+            memcpy(dst_p, src_p, m);
+            
+            munmap(src_p, m);
+            munmap(dst_p, m);
+            
+            src_o += m;
+            dst_o += m;
+            l -= m;
+            
+            m = l < MMAPSIZE ? l : MMAPSIZE;
+        }
+        
+    
+        if (lseek(sfd, src_o, SEEK_SET) == (off_t) -1) {
+            fprintf(stderr, "lseek(): %s\n", strerror(errno));
+            goto finish;
+        }
+        
+        if (lseek(dfd, dst_o, SEEK_SET) == (off_t) -1) {
+            fprintf(stderr, "lseek(): %s\n", strerror(errno));
+            goto finish;
+        }
+    }
+    
+    if (l > 0) {
+        if (!(buf = malloc(BUFSIZE)))
+            goto finish;
+
+        for (;;) {
+            ssize_t m;
+
+            if ((m = read(sfd, buf, BUFSIZE)) < 0) {
+                fprintf(stderr, "read(): %s\n", strerror(errno));
+                goto finish;
+            }
+
+            if (!m)
+                break;
+                
+            if (write(dfd, buf, m) < 0) {
+                fprintf(stderr, "write(): %s\n", strerror(errno));
+                goto finish;
+            }
+        }
+    }
+
+    r = 0;
+    
+finish:
+
+    return r;
+}
+
+int copy_file(const char *src, const char *dst) {
+    int sfd = -1, dfd = -1, r = -1;
+
+    if ((sfd = open(src, O_RDONLY)) < 0) {
+        fprintf(stderr, "open(%s, O_RDONLY): %s\n", src, strerror(errno));
+        goto finish;
+    }
+
+    if ((dfd = open(dst, O_RDWR|O_TRUNC|O_CREAT, 0666)) < 0) {
+        fprintf(stderr, "open(%s, O_RDWR|O_TRUNC|O_CREAT): %s\n", dst, strerror(errno));
+        goto finish;
+    }
+
+    if (copy_fd(sfd, dfd, (uint32_t) -1) < 0)
+        goto finish;
+
+    r = 0;
+
+finish:
+    
+    if (sfd >= 0)
+        close(sfd);
+
+    if (dfd >= 0)
+        close(dfd);
+
+    return r;
+}
+
+int copy_or_link_file(const char *src, const char *dst) {
+
+    if (link(src, dst) < 0) {
+
+        if (errno == EXDEV || errno == EPERM)
+            return copy_file(src, dst);
+
+        fprintf(stderr, "link(%s, %s): %s\n", src, dst, strerror(errno));
+        return -1;
+    }
+
+    return 0;
+}