The read() syscall is not guaranteed to return all data from a file. The
default ROM loader implementation currently does not take this into account,
instead failing if all bytes are not read at once. This change loads the ROM
using load_image_size() instead, which correctly reads all data using
multiple calls to read(). Also, the ROM size is now determined using the
get_image_size() function rather than using manual lseek().

Signed-off-by: Gregor Haas <gregorhaas1997@gmail.com>
---
 hw/core/loader.c | 17 ++---------------
 1 file changed, 2 insertions(+), 15 deletions(-)

diff --git a/hw/core/loader.c b/hw/core/loader.c
index 2f8105d7de..c2c61158f1 100644
--- a/hw/core/loader.c
+++ b/hw/core/loader.c
@@ -1076,7 +1076,6 @@ ssize_t rom_add_file(const char *file, const char *fw_dir,
     MachineClass *mc = MACHINE_GET_CLASS(qdev_get_machine());
     Rom *rom;
     ssize_t rc;
-    int fd = -1;
     char devpath[100];
 
     if (as && mr) {
@@ -1094,19 +1093,12 @@ ssize_t rom_add_file(const char *file, const char *fw_dir,
         rom->path = g_strdup(file);
     }
 
-    fd = open(rom->path, O_RDONLY | O_BINARY);
-    if (fd == -1) {
-        fprintf(stderr, "Could not open option rom '%s': %s\n",
-                rom->path, strerror(errno));
-        goto err;
-    }
-
     if (fw_dir) {
         rom->fw_dir  = g_strdup(fw_dir);
         rom->fw_file = g_strdup(file);
     }
     rom->addr     = addr;
-    rom->romsize  = lseek(fd, 0, SEEK_END);
+    rom->romsize  = get_image_size(rom->path);
     if (rom->romsize == -1) {
         fprintf(stderr, "rom: file %-20s: get size error: %s\n",
                 rom->name, strerror(errno));
@@ -1115,14 +1107,12 @@ ssize_t rom_add_file(const char *file, const char *fw_dir,
 
     rom->datasize = rom->romsize;
     rom->data     = g_malloc0(rom->datasize);
-    lseek(fd, 0, SEEK_SET);
-    rc = read(fd, rom->data, rom->datasize);
+    rc = load_image_size(rom->path, rom->data, rom->datasize);
     if (rc != rom->datasize) {
         fprintf(stderr, "rom: file %-20s: read error: rc=%zd (expected %zd)\n",
                 rom->name, rc, rom->datasize);
         goto err;
     }
-    close(fd);
     rom_insert(rom);
     if (rom->fw_file && fw_cfg) {
         const char *basename;
@@ -1159,9 +1149,6 @@ ssize_t rom_add_file(const char *file, const char *fw_dir,
     return 0;
 
 err:
-    if (fd != -1)
-        close(fd);
-
     rom_free(rom);
     return -1;
 }
-- 
2.45.2

> -----Original Message-----
> From: Gregor Haas <gregorhaas1997@gmail.com>
> Sent: Friday, June 28, 2024 9:51 AM
> To: qemu-devel@nongnu.org
> Cc: Yao, Xingtao/姚 幸涛 <yaoxt.fnst@fujitsu.com>; Gregor Haas
> <gregorhaas1997@gmail.com>
> Subject: [PATCH v3] hw/core/loader: allow loading larger ROMs
> 
> The read() syscall is not guaranteed to return all data from a file. The
> default ROM loader implementation currently does not take this into account,
> instead failing if all bytes are not read at once. This change loads the ROM
> using load_image_size() instead, which correctly reads all data using
> multiple calls to read(). Also, the ROM size is now determined using the
> get_image_size() function rather than using manual lseek().
> 
> Signed-off-by: Gregor Haas <gregorhaas1997@gmail.com>
> ---
>  hw/core/loader.c | 17 ++---------------
>  1 file changed, 2 insertions(+), 15 deletions(-)
> 
> diff --git a/hw/core/loader.c b/hw/core/loader.c
> index 2f8105d7de..c2c61158f1 100644
> --- a/hw/core/loader.c
> +++ b/hw/core/loader.c
> @@ -1076,7 +1076,6 @@ ssize_t rom_add_file(const char *file, const char *fw_dir,
>      MachineClass *mc = MACHINE_GET_CLASS(qdev_get_machine());
>      Rom *rom;
>      ssize_t rc;
> -    int fd = -1;
>      char devpath[100];
> 
>      if (as && mr) {
> @@ -1094,19 +1093,12 @@ ssize_t rom_add_file(const char *file, const char
> *fw_dir,
>          rom->path = g_strdup(file);
>      }
> 
> -    fd = open(rom->path, O_RDONLY | O_BINARY);
> -    if (fd == -1) {
> -        fprintf(stderr, "Could not open option rom '%s': %s\n",
> -                rom->path, strerror(errno));
> -        goto err;
> -    }
> -
>      if (fw_dir) {
>          rom->fw_dir  = g_strdup(fw_dir);
>          rom->fw_file = g_strdup(file);
>      }
>      rom->addr     = addr;
> -    rom->romsize  = lseek(fd, 0, SEEK_END);
> +    rom->romsize  = get_image_size(rom->path);
>      if (rom->romsize == -1) {
>          fprintf(stderr, "rom: file %-20s: get size error: %s\n",
>                  rom->name, strerror(errno));
> @@ -1115,14 +1107,12 @@ ssize_t rom_add_file(const char *file, const char
> *fw_dir,
> 
>      rom->datasize = rom->romsize;
>      rom->data     = g_malloc0(rom->datasize);
> -    lseek(fd, 0, SEEK_SET);
> -    rc = read(fd, rom->data, rom->datasize);
> +    rc = load_image_size(rom->path, rom->data, rom->datasize);
>      if (rc != rom->datasize) {
>          fprintf(stderr, "rom: file %-20s: read error: rc=%zd (expected %zd)\n",
>                  rom->name, rc, rom->datasize);
>          goto err;
>      }
> -    close(fd);
>      rom_insert(rom);
>      if (rom->fw_file && fw_cfg) {
>          const char *basename;
> @@ -1159,9 +1149,6 @@ ssize_t rom_add_file(const char *file, const char *fw_dir,
>      return 0;
> 
>  err:
> -    if (fd != -1)
> -        close(fd);
> -
>      rom_free(rom);
>      return -1;
>  }
> --
> 2.45.2

Reviewed-by: Xingtao Yao <yaoxt.fnst@fujitsu.com >