1 files changed, 111 insertions, 22 deletions

diff --git a/linux-user/linuxload.c b/linux-user/linuxload.c
index 745cce70ab..4a794f8cea 100644
--- a/linux-user/linuxload.c
+++ b/linux-user/linuxload.c
@@ -3,7 +3,9 @@
 #include "qemu/osdep.h"
 #include "qemu.h"
 #include "user-internals.h"
+#include "user-mmap.h"
 #include "loader.h"
+#include "qapi/error.h"
 
 #define NGROUPS 32
 
@@ -37,7 +39,7 @@ static int prepare_binprm(struct linux_binprm *bprm)
     int mode;
     int retval;
 
-    if (fstat(bprm->fd, &st) < 0) {
+    if (fstat(bprm->src.fd, &st) < 0) {
         return -errno;
     }
 
@@ -67,7 +69,7 @@ static int prepare_binprm(struct linux_binprm *bprm)
         bprm->e_gid = st.st_gid;
     }
 
-    retval = read(bprm->fd, bprm->buf, BPRM_BUF_SIZE);
+    retval = read(bprm->src.fd, bprm->buf, BPRM_BUF_SIZE);
     if (retval < 0) {
         perror("prepare_binprm");
         exit(-1);
@@ -76,6 +78,10 @@ static int prepare_binprm(struct linux_binprm *bprm)
         /* Make sure the rest of the loader won't read garbage.  */
         memset(bprm->buf + retval, 0, BPRM_BUF_SIZE - retval);
     }
+
+    bprm->src.cache = bprm->buf;
+    bprm->src.cache_size = retval;
+
     return retval;
 }
 
@@ -138,7 +144,7 @@ int loader_exec(int fdexec, const char *filename, char **argv, char **envp,
 {
     int retval;
 
-    bprm->fd = fdexec;
+    bprm->src.fd = fdexec;
     bprm->filename = (char *)filename;
     bprm->argc = count(argv);
     bprm->argv = argv;
@@ -147,29 +153,112 @@ int loader_exec(int fdexec, const char *filename, char **argv, char **envp,
 
     retval = prepare_binprm(bprm);
 
-    if (retval >= 0) {
-        if (bprm->buf[0] == 0x7f
-                && bprm->buf[1] == 'E'
-                && bprm->buf[2] == 'L'
-                && bprm->buf[3] == 'F') {
-            retval = load_elf_binary(bprm, infop);
+    if (retval < 4) {
+        return -ENOEXEC;
+    }
+    if (bprm->buf[0] == 0x7f
+        && bprm->buf[1] == 'E'
+        && bprm->buf[2] == 'L'
+        && bprm->buf[3] == 'F') {
+        retval = load_elf_binary(bprm, infop);
 #if defined(TARGET_HAS_BFLT)
-        } else if (bprm->buf[0] == 'b'
-                && bprm->buf[1] == 'F'
-                && bprm->buf[2] == 'L'
-                && bprm->buf[3] == 'T') {
-            retval = load_flt_binary(bprm, infop);
+    } else if (bprm->buf[0] == 'b'
+               && bprm->buf[1] == 'F'
+               && bprm->buf[2] == 'L'
+               && bprm->buf[3] == 'T') {
+        retval = load_flt_binary(bprm, infop);
 #endif
-        } else {
-            return -ENOEXEC;
-        }
+    } else {
+        return -ENOEXEC;
     }
-
-    if (retval >= 0) {
-        /* success.  Initialize important registers */
-        do_init_thread(regs, infop);
+    if (retval < 0) {
         return retval;
     }
 
-    return retval;
+    /* Success.  Initialize important registers. */
+    do_init_thread(regs, infop);
+    return 0;
+}
+
+bool imgsrc_read(void *dst, off_t offset, size_t len,
+                 const ImageSource *img, Error **errp)
+{
+    ssize_t ret;
+
+    if (offset + len <= img->cache_size) {
+        memcpy(dst, img->cache + offset, len);
+        return true;
+    }
+
+    if (img->fd < 0) {
+        error_setg(errp, "read past end of buffer");
+        return false;
+    }
+
+    ret = pread(img->fd, dst, len, offset);
+    if (ret == len) {
+        return true;
+    }
+    if (ret < 0) {
+        error_setg_errno(errp, errno, "Error reading file header");
+    } else {
+        error_setg(errp, "Incomplete read of file header");
+    }
+    return false;
+}
+
+void *imgsrc_read_alloc(off_t offset, size_t len,
+                        const ImageSource *img, Error **errp)
+{
+    void *alloc = g_malloc(len);
+    bool ok = imgsrc_read(alloc, offset, len, img, errp);
+
+    if (!ok) {
+        g_free(alloc);
+        alloc = NULL;
+    }
+    return alloc;
+}
+
+abi_long imgsrc_mmap(abi_ulong start, abi_ulong len, int prot,
+                     int flags, const ImageSource *src, abi_ulong offset)
+{
+    const int prot_write = PROT_READ | PROT_WRITE;
+    abi_long ret;
+    void *haddr;
+
+    assert(flags == (MAP_PRIVATE | MAP_FIXED));
+
+    if (src->fd >= 0) {
+        return target_mmap(start, len, prot, flags, src->fd, offset);
+    }
+
+    /*
+     * This case is for the vdso; we don't expect bad images.
+     * The mmap may extend beyond the end of the image, especially
+     * to the end of the page.  Zero fill.
+     */
+    assert(offset < src->cache_size);
+
+    ret = target_mmap(start, len, prot_write, flags | MAP_ANON, -1, 0);
+    if (ret == -1) {
+        return ret;
+    }
+
+    haddr = lock_user(VERIFY_WRITE, start, len, 0);
+    assert(haddr != NULL);
+    if (offset + len <= src->cache_size) {
+        memcpy(haddr, src->cache + offset, len);
+    } else {
+        size_t rest = src->cache_size - offset;
+        memcpy(haddr, src->cache + offset, rest);
+        memset(haddr + rest, 0, len - rest);
+    }
+    unlock_user(haddr, start, len);
+
+    if (prot != prot_write) {
+        target_mprotect(start, len, prot);
+    }
+
+    return ret;
 }